Neurosurgery Flashcards

Question

You are seeing a patient in the trauma bay who was involved in a motor vehicle accident leading to a skull base fracture that appears to be a transverse fracture of the clivus. All of the following should be performed except? A. CBC/Electrolyte panel B. NG tube insertion C. CT angiogram head and neck D. Cervical spine CT

Answer 1

A. CBC/Electrolyte panel **B. NG tube insertion** C. CT angiogram head and neck D. Cervical spine CT ## Footnote Clival fractures are severe injuries that are often fatal. They can be associated with cranial nerve deficits, diabetes insipidus, and anterior/posterior circulation vascular injury. NG tube insertion should be avoided as there have been reports of intracranial NG tube insertion through a diastased fracture of the clivus. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 885.

Answer 2

A. Type I B. Type II **C. Type III** D. Type IV ## Footnote There are three types of Lefort facial fractures, and of these, type III involves the zygomatic arches, the nasofrontal suture, and orbital floors. Given the type of fracture and the forces required, there is a high incidence of brain injury with type III Lefort fractures. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 887.

Answer 3

A. Operative elevation **B. Observation** ## Footnote In a neurologically normal infant, this fracture should be managed nonoperatively. This is the classic “ping-pong” fracture, and over time the CSF pulsations will remodel the bone and heal this fracture. Operative intervention is generally not required. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 915.

Answer 4

**A. Growing skull fracture** B. Arachnoid cyst C. Intraparenchymal hemorrhage D. Normal bone healing ## Footnote This CT scan demonstrates widening of the skull fracture with evidence of fluid below the fracture. This is consistent with a growing skull fracture, and is often seen with a dural laceration and CSF leak that goes unrepaired. It is different than an arachnoid cyst and should be managed operatively with dural closure. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 915.

Answer 5

A. Observation B. Percutaneous drainage C. Cranioplasty **D. Circumferential craniotomy and dural repair** ## Footnote This CT scan demonstrates widening of the skull fracture with evidence of fluid below the fracture. This is consistent with a growing skull fracture, and is often seen with a dural laceration and CSF leak that goes unrepaired. It is different than an arachnoid cyst and should be managed operatively with dural closure. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 915.

Answer 6

A. Diffuse axonal injury **B. Bilateral subdural hematomas** C. Intraparenchymal hemorrhage D. Epidural hematoma ## Footnote Suspected non-accidental trauma workup should include some form of intracranial injury. When a child is shaken, bilateral subdural hematomas can develop due to shear forces exerted on the brain leading to tearing of bridging veins. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 916.

Answer 7

**A. Nonaccidental trauma** B. Benign subdural effusion in infants C. Acute high altitude sickness D. Acute ICP increase ## Footnote While all options listed can cause retinal hemorrhages, nonaccidental trauma is the most common cause seen in an infant. 16/26 battered children < 3 years of age had RH on fundoscopy, while 1/32 nonbattered children with head injury had RH. The single false positive was due to traumatic parturition. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 916.

Answer 8

A. PTEN **B. GFAP** C. Amyloid precursor protein D. Tau protein ## Footnote GFAP, a marker of neurons, has been shown to be associated with acute traumatic brain injury and may be used in the future to determine which patients need to undergo CT scan of the brain. Further Reading: Brain injury biomarkers may improve the predictive power of the IMPACT outcome calculator. J Neurotrauma. 2012, 1770–1778.

Answer 9

**A. Continued medical management** B. Withdrawal of care C. Decompressive hemicraniectomy D. Posterior fossa decompression ## Footnote According to the initial results of the DECRA trial, decompressive hemicraniectomy in the setting of elevated ICP in patients < 60 years of age within 72 hours of injury refractory to first line medical management was associated with a higher rate of unfavorable outcome than the control group who did not undergo surgery. In a subgroup analysis, there was no difference when patients who had bilaterally unreactive pupils were controlled for (initial analysis had significantly higher rate of bilaterally unreactive pupils in the surgical arm). While some providers would perform a decompression, strictly according to the results of the DECRA trial, this will lead to unfavorable outcomes. Further surgical trials are underway, and results depend on the definition of favorable outcome. Further Reading: Kolias AG. Traumatic brain injury in adults. Pract Neurol. 2013, 228–235.

Answer 10

A. AP diameter > 12 cm B. Drilling to the edge of the sagittal sinus **C. Drilling to the floor of the middle fossa** D. Intraoperative EVD placement ## Footnote It is important to ensure that a decompressive craniectomy is large enough to not only decompress the cerebral hemisphere, but to also avoid complications that have been shown to occur when the AP diameter of the craniectomy is < 12 cm. Subsequent herniation of the brain can, through the craniectomy defect, lead to vascular injury and further infarction of the brain. When uncal herniation is suspected, making sure the craniectomy reaches the floor of the middle fossa is important to fully decompress the temporal lobe. Further Reading: Wagner S. Suboptimum hemicraniectomy as a cause of additional cerebral lesions in patients with malignant infarction of the MCA. J Neurosurg. 2001, 693–696.

Answer 11

**A. Hypotension** B. Hypertension C. Bradycardia D. Irregular respirations ## Footnote Cushing’s triad is seen often during terminal elevation of ICP immediately before herniation. It consists of bradycardia, hypertension, and breathing irregularities. If these findings are seen together in a patient with elevated ICP, action should be taken immediately to decrease ICP as the patient is likely about to herniate. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 858.

Answer 12

A. ~ 1 minute **B. ~ 30 minutes** C. ~ 12 hours D. ~ 24 hours E. ~ 48 hours ## Footnote CO2 is a potent vasodilator and hyperventilation can be used to decrease intracranial pressure by decreasing CO2 . The brain is able to buffer efficiently, and therefore this technique may only transiently decrease ICP as the brain will adjust to new levels of CO2 within 20 to 30 minutes. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 868.

Answer 13

A. 16 to 20 mm Hg B. 21 to 25 mm Hg C. 26 to 30 mm Hg **D. 31 to 35 mm Hg** E. 36 to 40 mm Hg ## Footnote CO2 is a potent vasodilator and hyperventilation can be used to decrease intracranial pressure by decreasing CO2 . The brain is able to buffer efficiently, and therefore this technique may only transiently decrease ICP as the brain will adjust to new levels of CO2 within 20 to 30 minutes. You are aiming for a PaCO2 of 31 to 35 mm Hg. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 868.

Answer 14

A. 306 B. 312 C. 318 **D. 324** ## Footnote Mannitol is a very effective osmotic diuretic that is often used to decrease intracranial pressure. When utilized in a scheduled fashion, monitoring of serum osmolality should take place. When serum osmolality is greater than 320, other options should be considered for medical treatment of raised ICP. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 868.

Answer 15

A. 8 cm back from the nasion, mid-pupillary line **B. 11 cm back from the nasion, mid-pupillary line** C. 14 cm back from the nasion, mid-pupillary line D. 3 cm up from the pinna, 3 cm posterior ## Footnote Kocher’s point is thought to be located generally between 10.5 and 11.5 cm back from the nasion and roughly 3 to 3.5 cm lateral, or in the mid-pupillary line. Generally speaking this is a good location to place a burr hole for an EVD placement for acute hydrocephalus. In many situations, simply placing the EVD perpendicular to the skull will lead to ventricular puncture, depending on ventricular size. Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 473.

Answer 16

A. 1.5% **B. 3%** C. 7% D. 23.4% ## Footnote Hypertonic saline can be used for ICP management either as a first line agent or in patient’s refractory to mannitol administration. The patient can be given 3% saline as a continuous infusion through a peripheral IV, but 7% and 23.4% given as a bolus should be administered through a central line to avoid deleterious effects to the extremities. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 875.

Answer 17

A. 100 mL **B. 150 mL** C. 200 mL D. 250 mL ## Footnote The approximate volume of CSF in the system is 150 mL at any given time. Roughly 450 to 500 mL of CSF is produced each day, and the CSF turns over 3 times daily. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 856.

Answer 18

A. 8 **B. 10** C. 12 D. 14 E. 15 ## Footnote This patient has a GCS of 10. E = 2, V = 3, M = 5. Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 496.

Answer 19

**A. 4t** B. 6t C. 8t D. 3t E. 14t ## Footnote This patient has a GCS of 4t. E = 1, V = 1t, M = 2. This patient is decerebrate posturing (M = 2), is not opening his eyes (E = 1), and is intubated (V = 1t). Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edi- tion, 2010, page 496.

Answer 20

A. 8.7 cm H2O B. 17.4 cm H2O **C. 13.6 cm H2O** D. 21.4 cm H2O ## Footnote There is a lack of convention among neurosurgeons as to what system should be utilized, mm Hg or cm H2 O. 1 mm Hg = 1.36 cm H2 O, meaning that 10 mm Hg = 13.6 cm H2 O. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 861.

Answer 21

**A. Lundberg A waves** B. Lundberg B waves C. Lundberg C waves D. Lundberg D waves E. Lundberg E waves ## Footnote There are three types of Lundberg waves seen during ICP monitoring: A, B, and C. Lundberg A (plateau waves) are associated with extremely high elevation of ICP that plateaus for 5 to 20 minutes and then decreases to ~ 20 mm Hg for 30 to 45 minutes followed by another elevation. MAP increases can be seen as well. These waves are not often seen in the ICU setting as active ICP management is taking place. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 865.

Answer 22

A. P1 **B. P2** C. P3 D. P4 E. P5 ## Footnote The second ICP wave, P2, represents the pressure when the aortic pulse bounces off the ventricular wall (P1 is the aortic pulse itself). When the ventricular walls are stiffened due to hydrocephalus and lack compliance, the P2 wave will be greatly increased and will lead to the classic ICP waveform that is indicative of elevated ICP. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 864.

Answer 23

A. > 20 **B. > 50** C. > 100 D. > 150 E. > 200 ## Footnote Cerebral perfusion pressure is calculated by subtracting ICP from the mean arterial pressure. The brain can autoregulate CPP to maintain stable cerebral blood flow at 55 to 60 mL/100 mg/min. This autoregulation curve in a normal brain keeps flow stable between CPPs of 50 and 150. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 869.

Answer 24

A. 45 **B. 85** C. 115 D. 145 E. 165 ## Footnote Cerebral perfusion pressure is calculated by subtracting ICP from the mean arterial pressure. The brain can autoregulate CPP to maintain stable cerebral blood flow at 55 to 60 mL/100 mg/min. This autoregulation curve in a normal brain keeps flow stable between CPPs of 50 and 150. It is thought during severe TBI that autoregulation fails and that CBF matches CPP much more closely. In this setting, an MAP of 85 with an ICP of 25 will give you a CPP of 60, exactly matching the standard CBF of the brain in normal conditions. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 869.

Answer 25

A. 0 **B. 3** C. 6 D. 9 E. 12 ## Footnote This patient has a GCS of 3t. E = 1, V = 1t, M = 1. GCS of 0 is not possible. You get 3 points just for showing up. Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 496.

Answer 26

A. Mannitol B. Hypertonic saline C. Propofol **D. Pentobarbital** E. Ketamine ## Footnote Pentobarbital is a last resort medical management strategy for reducing raised ICP. It provides maximal reduction in CMRO2 and CBF when compared to other agents, but should be used as a last resort. It should be titrated to burst suppression on EEG. It can cause severe hypotension and paralytic ileus. It also stores within fat deposits so dosing should be adjusted. It can confound any attempts at brain death examination until it has been completely metabolized from the system, which can take days. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 875.

Answer 27

A. Motor mapping B. Diffusion tensor imaging **C. Awake language mapping** D. Somatosensory evoked potentials E. EMG ## Footnote This imaging demonstrates a left frontal likely low grade astrocytoma of the frontal region. This should concern you for potential involvement of Broca’s area, and may make you consider performing the procedure awake with language mapping. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 160.

Answer 28

A. PET scan B. Diffusion tensor imaging **C. Functional MRI** D. Perfusion MRI E. Perfusion C ## Footnote This MRI demonstrates a left frontal likely low grade astrocytoma frontal region. This should concern you for potential involvement of Broca’s area, and you could consider performing an fMRI to localize language structures prior to surgical decision making. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 160.

Answer 29

**A. Motor mapping** B. Awake language mapping C. Somatosensory evoked potentials D. EMG ## Footnote This MRI demonstrates a likely anaplastic astrocytoma of the posterior frontal lobe on the right. There is concern that this tumor involves the motor strip and thus intraoperative motor mapping could be useful during this resection. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 160.

Answer 30

A. Doubling of signal amplitude B. Signal dampening **C. Phase reversal** D. Phase doubling ## Footnote When motor mapping for tumor resection near the motor strip, you are looking for phase reversal of the signal on monitoring. This shows the change from the sensory cortex to the motor cortex. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 160.

Answer 31

A. 2 B. 3 C. 4 **D. 5** E. 6 ## Footnote These intraoperative recordings demonstrate phase reversal between electrodes 3 and 5. This means that in this scenario the motor strip is likely located under electrode 5. Electrode 4 is very likely located directly over the central sulcus, given the lack of response. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 160.

Answer 32

A. Meningioma **B. Metastases** C. Glioblastoma D. Lymphoma E. Low-grade glioma ## Footnote Metastases are the most common tumor of the central nervous system, and account for just over 50% of intracranial tumors. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 451.

Answer 33

A. Lymphoma **B. Lung** C. Colorectal D. Melanoma E. Renal ## Footnote Overall, lung cancer has the highest incidence of brain metastases based on autopsy data currently available. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 801. Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 451.

Answer 34

A. Melanoma B. Lung C. Colorectal **D. Breast** E. Renal ## Footnote Breast cancer metastases are the most common metastatic tumor to the brain in females. Further Reading: Schouten LJ. Incidence of brain metastases in a cohort of patients with carcinoma of the breast, colon, kidney, lung and melanoma. Cancer. 2002.

Answer 35

A. Total spine MRI B**. CT chest, abdomen, and pelvis** C. Gamma knife D. Whole brain radiation ## Footnote This MRI demonstrates evidence of metastatic disease. In a patient with no prior history of primary cancer, workup should proceed with a CT CAP to look for primary disease. Further Reading: Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 451.

Answer 36

A. Lymphoma **B. Renal cell carcinoma** C. Squamous cell lung carcinoma D. Ductal carcinoma in situ E. Colon adenocarcinoma ## Footnote Renal cell carcinoma has a higher propensity for hemorrhagic conversion of a cerebral metastatic lesion. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 805. Bernstein, Berger. Neuro-Oncology: The Essentials. 3rd edition, 2015, page 451.

Answer 37

**A. Multiple myeloma** B. Thyroid C. Malignant melanoma D. Renal cell carcinoma ## Footnote Of the tumor types listed here, multiple myeloma is radiosensitive. The other lesions are highly resistant. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 809.

Answer 38

A. Multiple myeloma B. Breast cancer C. Small cell lung cancer **D. Renal cell carcinoma** ## Footnote Of the tumor types listed here, renal cell carcinoma is highly resistant to radiation. The other lesions are considered radiosensitive to varying degrees. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 809.

Answer 39

**A. 70** B. 80 C. 90 D. 100 E. 110 ## Footnote KPS is used to determine patient function in ollow-up for many tumor resections. A KPS of 70 or greater means the patient is able to at least care or himself or herself without assistance. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1358.

Answer 40

**A. Surgical resection** B. Gamma knife C. Observation D. Biopsy ## Footnote In patients with a single brain met (of any type) with a KPS > 70 and no evidence of extra cranial disease, surgery plus radiation increased median survival by 25 weeks. Surgical resection should be offered in this case in order to obtain tissue diagnosis if no primary can be found. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 804.

Answer 41

A. Pachymeninges **B. Leptomeninges** C. Virchow-Robin spaces D. Pia mater ## Footnote Melanocytes are found in the leptomeninges and are thought to be the probable origination point for primary CNS melanoma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 701.

Answer 42

A. 10% **B. 33%** C. 66% D. 90% E. 100% ## Footnote Nearly 33% of patients with incidentally discovered meningiomas will exhibit no growth over a 3-year follow-up period. Many of these patients can simply be observed depending on symptomatology. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 690.

Answer 43

A. Oligodendrocytes **B. Arachnoid cap cells** C. Pachymeninges D. Pia mater ## Footnote Meningiomas arise from arachnoid cap cells of the CNS. They can arise from wherever these arachnoid cap cells are found, including between the brain and skull, ventricles, and surrounding the spinal cord. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 690.

Answer 44

**A. ~ 1 to 3%** B. ~ 8 to 10% C. ~ 13 to 15% D. ~ 18 to 20% E. ~ 21 to 23% ## Footnote Meningiomas are thought to have roughly 1 to 3% incidence in the general population > 60 years of age based on autopsy studies. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 690.

Answer 45

A. Sphenoid wing **B. Parasagittal** C. Convexity D. Planum sphenoidale E. Petrous apex ## Footnote Parasagittal meningiomas are thought to be the most common location, followed by convexity meningiomas, based on a series of 336 cases. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 691.

Answer 46

A. Medulloblastoma B. Frontal glioblastoma **C. Olfactory groove meningioma** D. Clival chordoma ## Footnote Foster-Kennedy syndrome (anosmia, ipsilateral optic atrophy, and contralateral papilledema) was classically described in the setting of an olfactory groove meningioma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 691.

Answer 47

A. Anaplastic B. Gemistocytic C. Protoplasmic **D. Fibrillary** ## Footnote Fibrillary astrocytoma is the most common subtype of WHO grade II astrocytoma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 615.

Answer 48

A. Observation B. XRT alone C. Chemotherapy + XRT **D. Surgical resection** ## Footnote Surgical resection is considered the principal treatment for low-grade gliomas to both establish the diagnosis and for cytoreduction. More aggressive surgical excision has been shown to be associated with better outcome and further time to malignant transformation. XRT and chemotherapy may follow later in the disease course. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 620.

Answer 49

A. No difference in progression-free survival B. 2-year increase in progression-free survival **C. 5-year increase in progression-free survival** D. 8-year increase in progression-free survival ## Footnote In subtotally resected low-grade gliomas, 54 Gy XRT has been associated with an increased PFS from 3.4 to 5.3 years and is recommended as an early adjuvant treatment. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 620.

Answer 50

**A. No difference in progression-free survival** B. 2-year increase in progression-free survival C. 5-year increase in progression-free survival D. 8-year increase in progression-free survival ## Footnote In gross totally resected low-grade gliomas, 54 Gy XRT has been associated with no increase in PFS and should be deferred until progression occurs. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 620.

Answer 51

A. > 50% B. > 70% C. > 85% D. > 95% **E. > 97%** ## Footnote Extent of resection matters when undergoing attempted gross total resection of a GBM. Extent of resection > 97% has been shown to be associated with prolonged overall survival. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 621.

Answer 52

A. 60 Gy XRT + PCV chemotherapy B. 25 Gy XRT + temozolomide chemotherapy C. 25 Gy XRT + PCV chemotherapy **D. 60 Gy XRT + temozolomide chemotherapy** ## Footnote The Stupp regimen of chemoradiation for GBM consists of 60 Gy XRT in fractions along with concurrent TMZ and adjuvant chemotherapy. PCV chemotherapy was attempted, but showed no benefit in an RCT prior to publication of the Stupp regimen. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 622.

Answer 53

A. 11.5 months **B. 14.6 months** C. 12.1 months D. 18.3 months E. 20.7 months ## Footnote The Stupp regimen of chemoradiation for GBM consists of 60 Gy XRT in fractions along with concurrent TMZ and adjuvant chemotherapy. In the classic article, median survival increased from 12.1 months to 14.6 months. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 622.

Answer 54

A. 6.3 months **B. 10.8 months** C. 23.4 months D. 35.5 months E. 40.2 months ## Footnote The Stupp regimen of chemoradiation for GBM consists of 60 Gy XRT in fractions along with concurrent TMZ and adjuvant chemotherapy. In the classic article, median survival increased from 12.1 months to 14.6 months. When a subgroup of patients with MGMT promoter methylation was studied, it was found that these patients had a median survival of 23.4 months compared to 12.6 in non–MGMT methylated patients, leading to a median overall survival benefit of 10.8 months. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 622.

Answer 55

A. Peripheral neuropathy **B. Myelosuppression** C. Cardiomyopathy D. Leukocytosis E. Seizures ## Footnote The main side effect of TMZ chemotherapy is myelosuppression, and it is an otherwise well tolerated chemotherapeutic. Patients undergo routine neutrophil testing and should have a neutrophil count of > 1.5 × 10^9/L and a platelet count > 100. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 622.

Answer 56

A. Postoperative blood products B. Tumor recurrence **C. Pseudoprogression** D. Ischemic stroke ## Footnote In MGMT promoter methylated GBM patients, contrast enhancement can be seen at roughly 3 months post gross total resection and Stupp regimen. It is consistent with pseudoprogression and often decreases on subsequent imaging and symptoms can resolve with steroids. It is associated with radiation kill of the tumor. At this time there are no definitive imaging studies that can prove pseudoprogression vs tumor recurrence, but this is an active area of research. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 623.

Answer 57

A. Hypertension B. Arterial thromboembolism C. Hemorrhage **D. Myelosuppression** ## Footnote Bevacizumab is a monoclonal antibody against VEGF and is FDA approved for the treatment of recurrent GBM. Its side effect profile consists of hypertension, arterial thromboembolism, hemorrhage, GI perforations, wound healing complications, and fistula formation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 624.

Answer 58

**A. 1 to 20 years** B. 21 to 40 years C. 41 to 60 years D. 61 to 80 years E. 81 to 100 years ## Footnote Pilocytic astrocytoma is a WHO grade I tumor with a predilection for younger patients. Approximately 75% of these tumors present in patients less than 20 years of age. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 630.

Answer 59

**A. Observation** B. Early XRT C. Temozolomide chemotherapy D. Gamma knife ## Footnote Pilocytic astroyctomas in the pediatric population that are incompletely resected should be initially observed as the rate of growth over 5, 10, or even 20 years can be minimal. Radiation and chemother- apy should be saved for obvious recurrence with growth demonstrated on serial imaging studies. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 631.

Answer 60

A. 5 years B. 10 years C. Patient’s age at diagnosis + 5 years **D. Patient’s age at diagnosis + 9 months** ## Footnote Collins’ law suggests that pediatric patients with pilocytic astrocytomas can be considered cured if there is no recurrence after enough time has passed adding the patient’s age at time of diagnosis + 9 months. It is controversial, but often quoted. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 631.

Answer 61

A. Sphenoid wing meningioma **B. Optic glioma** C. Thyrotoxicosis D. Orbital neurofibroma ## Footnote Optic gliomas are found in patients with neurofibromatosis and often present with unilateral painless proptosis. Visual loss occurs when the glioma has reached the chiasm or is causing significant mass effect on the optic nerve. These lesions can be cured if complete excision of the optic nerve and eye occur before the tumor has invaded the optic chiasm. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 632.

Answer 62

A. Surgical resection B. Biopsy C. Chemotherapy **D. Observation** E. Radiation ## Footnote This MRI demonstrates diffuse enlargement of the brainstem consistent with a diffuse intrinsic pontine glioma. Diagnosis can often be made based on MRI scans and surgical resection/biopsy should be avoided unless an obvious exophytic component is present. Children with this diagnosis die within 6 to 12 months, and XRT may not prolong survival. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 634.

Answer 63

A. Frontal lobe **B. Temporal lobe** C. Brainstem D. Cerebellum E. Occipital lobe ## Footnote PXAs tend to occur in the temporal lobe, are cystic with an enhancing nodule, and present with seizures. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 636.

Answer 64

A. 60 Gy XRT + temozolomide chemotherapy B. 60 Gy XRT + PCV chemotherapy **C. PCV chemotherapy alone** D. Temozolomide chemotherapy alone ## Footnote For pathology proven oligodendrogliomas, postoperative PCV chemotherapy has shown to be beneficial. XRT is controversial, and often saved for malignant transformation or recurrent growth. At this time immediate XRT post-resection is not often recommended. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 640.

Answer 65

A. Visual loss B. Medial rectus palsy **C. Facial weakness** D. Tongue weakness ## Footnote Ependymomas often present in the fourth ventricle, originating from the floor of the fourth ventricle. Given their invasiveness, they may involve the facial colliculus which is located in the floor of the fourth ventricle, making facial weakness a likely cranial nerve deficit. Lateral rectus palsy (CN VI involvement) can be seen as well. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 643.

Answer 66

A. Whole body PET CT B. CT chest/abdomen/pelvis **C. MRI spinal axis** D. Technetium bone scan ## Footnote Ependymomas often present in the fourth ventricle, originating from the floor of the fourth ventricle. They can cause drop metastases within the spinal canal, and thus MRI imaging of the entire neuraxis should be performed prior to intervention. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 644.

Answer 67

A. XRT + temozolomide chemotherapy B. XRT + PCV chemotherapy **C. XRT alone** D. Temozolomide alone ## Footnote Ependymomas often present in the fourth ventricle, originating from the floor of the fourth ventricle. They tend to be radiosensitive and have not been shown to benefit from added chemotherapy. Traditional XRT therapy included 45 to 48 Gy to the tumor bed with 15 to 20 Gy reserved for recurrence. With the development of 3D conformal XRT, doses of 59.4 Gy to the tumor bed have been given. Prophylactic spinal XRT is usually given only if there is evidence of drop metastases on imaging. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 644.

Answer 68

A. Glioblastoma **B. Central neurocytoma** C. Intraventricular meningioma D. Intraventricular lymphoma E. Pleomorphic xanthoastrocytoma ## Footnote Central neurocytomas are WHO grade II neuronal tumors often found attached to the septum pellucidum in the frontal horn of the lateral ventricles. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 645.

Answer 69

A. Frontal lobe B. Mesial temporal lobe **C. Third ventricle** D. Anterior temporal pole E. Fourth ventricle ## Footnote Gelastic seizures are characterized by inappropriate laughter and are often seen with hypothalamic hamartomas or hypothalamic gliomas with a mass in the third ventricle. Further Reading: Baltuch, Villemure. Operative Techniques in Epilepsy Surgery, 2009, page 83.

Answer 70

A. XRT + temozolomide chemotherapy B. XRT alone C. Temozolomide chemotherapy alone **D. Observation** ## Footnote DNETs are often seen in the temporal lobe and appear to have nodular enhancement on MRI. They are WHO grade I tumors and are associated with medically intractable epilepsy. After gross total resection, observation is recommended as XRT and chemotherapy have not shown any benefit in these benign tumors. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 647.

Answer 71

**A. Cardiac arrhythmia** B. Life-threatening hemorrhage C. Seizure D. Stroke ## Footnote Paraganglioma (glomus tumors) can secrete epinephrine and norepinephrine based on histologic subtype, and therefore aggressive manipulation can lead to release of these catecholamines and hypertension/cardiac arrhythmias may occur. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 653.

Answer 72

A. Glomus tympanicum B. Glomus jugulare C. Glomus intravagale **D. Carotid body tumor** ## Footnote Carotid body tumor is the most common paraganglioma of the ones listed here. Overall, pheochromocytoma is the most common paraganglioma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 653.

Answer 73

**A. Sympathetic ganglion** B. Peripheral nerve C. Dorsal root ganglion D. Free nerve endings ## Footnote Neuroblastomas are aggressive tumors that arise from the sympathetic ganglion. They often present in the adrenal gland (40%), but can present anywhere along the sympathetic chain and in certain presentations can cause a Horner’s syndrome. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 657.

Answer 74

A. Germinoma **B. Choriocarcinoma** C. Embryonal carcinoma D. Mature teratoma ## Footnote CSF markers are important for pineal region tumors. In this case there is an isolated elevation of B-HCG which leads to the diagnosis of choriocarcinoma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 660.

Answer 75

**A. Germinoma** B. Choriocarcinoma C. Embryonal carcinoma D. Mature teratoma ## Footnote CSF markers are important for pineal region tumors. In this case there is elevation of both B-HCG and placental alkaline phosphatase (PLAP), which is suggestive of germinoma. While PLAP is often positive in germinomas, B-HCG has been shown to be positive in 10 to 50% of cases based on the microarchitecture of the tumor and whether or not syncytiotrophoblasts are present. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 660.

Answer 76

A. Germinoma B. Choriocarcinoma C. Embryonal carcinoma **D. Mature teratoma** ## Footnote CSF markers are important for pineal region tumors. In this case, the markers are all negative, and this can be the case with a mixed germ cell tumor or a mature teratoma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 660.

Answer 77

A. Germinoma B. Choriocarcinoma **C. Embryonal carcinoma** D. Mature teratoma ## Footnote CSF markers are important for pineal region tumors. In this case, AFP is elevated while the other markers are negative. This is suggestive of embryonal carcinoma, yolk sac carcinoma, or immature teratoma. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 660.

Answer 78

A. Facial weakness **B. Facial numbness** C. Taste changes D. Otalgia ## Footnote Patients with vestibular schwannomas are actually more likely to present with facial numbness than weakness. Often times the facial nerve is distorted by the tumor but no weakness is present. However, with fairly minor compression of the trigeminal nerve, facial numbness can occur. This is likely due to resiliency of motor nerves compared to sensory nerves. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 671.

Answer 79

A. Facial weakness B. Facial numbness C. Taste changes **D. Hearing loss** ## Footnote Unilateral hearing loss is overall the most common presentation of vestibular schwannomas. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 672.

Answer 80

A. Surgical resection B. Stereotactic radiosurgery **C. Observation** D. Chemotherapy ## Footnote In patients with a vestibular schwannoma < 15 mm in size with intact hearing, observation with serial scans every 6 months should be the initial next step. If/when tumor growth is documented > 2 mm, treatment is recommended. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 676.

Answer 81

**A. Anterior** B. Posterior C. Superior D. Inferior E. Lateral ## Footnote The facial nerve is displaced anteriorly in up to 75% of cases, but can also be seen superiorly displaced. It can be completely thinned out over the surface of the tumor, so monitoring is recommended. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 679.

Answer 82

**A. 20%** B. 40% C. 60% D. 80% E. 100% ## Footnote Hemangioblastomas can be associated with VHL, but can also occur sporadically. They seem to be associated with VHL approximately 20% of the time. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 701.

Answer 83

A. Hemangioblastoma B. Pheochromocytoma **C. Paraganglioma** D. Renal cell carcinoma ## Footnote VHL is a disease associated with abnormalities on chromosome 3. It is associated with multiple tumor types including hemangioblastomas, retinal hemangioblastomas, pheochromocytomas, renal cell carcinoma, cystadenomas, pancreactic neuroendocrine tumors, and endolymphatic sac tumors. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 705.

Answer 84

A. Surgical resection followed by XRT and methotrexate chemotherapy **B. XRT + methotrexate chemotherapy** C. XRT + temozolomide chemotherapy D. Surgical resection followed by XRT and temozolomide chemotherapy ## Footnote Primary CNS lymphoma that is non-AIDS related and biopsy proven is best treated with XRT and methotrexate chemotherapy. There is no role for surgical debulking as this has demonstrated no improvement in survival in this patient population. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 713.

Answer 85

**A. 3 to 4%** B. 15 to 16% C. 30 to 31% D. 48 to 49% E. 55 to 56% ## Footnote Primary CNS lymphoma that is non-AIDS related and biopsy proven is best treated with XRT and methotrexate chemotherapy. There is no role for surgical debulking as this has demonstrated no improvement in survival in this patient population. Approximate 5-year survival is 3 to 4%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 713.

Answer 86

A. > 5 mm **B. > 1 cm** C. > 2 cm D. > 3 cm E. > 3.5 cm ## Footnote Pituitary adenomas are considered macroadenomas after they have grown to >1 cm in size. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 718.

Answer 87

A. 15% B. 35% C. 50% **D. 65%** E. 80% ## Footnote Approximately 65% of pituitary tumors secrete an active hormone, with prolactin being the most commonly secreted hormone (48%), followed by growth hormone (10%), ACTH (6%), and TSH (1%). Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 719.

Answer 88

A. Right homonymous hemianopia B. Left superior quadrant hemianopia C. Central scotoma **D. Bitemporal hemianopia** ## Footnote Pituitary macroadenomas cause compression of the optic chiasm and given their midline location lead to bitemporal hemianopia. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 720.

Answer 89

A. B-HCG B. AFP **C. Sodium** D. Hematocrit ## Footnote Suprasellar germinomas can lead to compression of the pituitary stalk and lead to diabetes insipidus. With elevated serum sodium in a suprasellar mass, germinoma should be considered. Further Reading: Schwartz, Anand. Endoscopic Pituitary Surgery, 2012, page 53.

Answer 90

A. Hypotension **B. Visual field cut** C. Hypernatremia D. Elevated urine output ## Footnote Pituitary apoplexy occurs when a pituitary tumor hemorrhages into the sella. These patients often need emergent corticosteroid administration, but progressive visual field deficit is a reason to emergently decompress the sella. This should ideally be performed within 7 days of onset to promote full recovery. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 721.

Answer 91

**A. Cushing’s disease** B. Cushing’s syndrome C. Nelson’s syndrome D. Pituitary apoplexy ## Footnote Cushing’s syndrome describes the general features of hypercortisolism, whereas Cushing’s disease is Cushing’s syndrome caused by an ACTH secreting pituitary adenoma. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 723.

Answer 92

A. Cushing’s disease B. Cushing’s syndrome **C. Nelson’s syndrome** D. Pituitary apoplexy ## Footnote Nelson’s syndrome occurs when ACTH producing pituitary adenoma cells remain after bilateral adrenalectomy for Cushing’s disease. Given the cross-reactivity between ACTH and melanocyte stimulating hormone, patients notice hyperpigmentation and signs/symptoms of an enlarging pituitary mass. She should undergo surgical resection of the mass. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 725.

Answer 93

A. Lung cancer **B. Colon cancer** C. Pancreatic cancer D. Hepatocellular carcinoma ## Footnote Patients with growth hormone–secreting tumors and acromegaly have a two times increased risk of colon cancer compared to the normal population. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 726.

Answer 94

A. D1 dopamine receptor **B. D2 dopamine receptor** C. GABA receptor D. Glutamate receptor ## Footnote The main medication used for prolactinomas currently is cabergoline, a D2 receptor agonist, compared to bromocriptine which is a nonselective (D1 and D2) dopamine agonist. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 740.

Answer 95

A. Seizures B. Diarrhea **C. Mitral regurgitation** D. Diabetes insipidus ## Footnote The main medication used for prolactinomas currently is cabergoline, a D2 receptor agonist, and it can lead to cardiac valve regurgitation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 740.

Answer 96

A. GH receptor antagonist B. Dopamine agonist **C. Somatostatin analogue** D. Adrenal steroid synthesis inhibitor ## Footnote While many growth hormone–secreting pituitary adenomas can be treated with surgery, occasionally medical management is attempted using octreotide, which is a somatostatin analogue. Tumor volume decreases in approximately 30% of patients. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 742.

Answer 97

**A. GH receptor antagonist** B. Dopamine agonist C. Somatostatin analogue D. Adrenal steroid synthesis inhibitor ## Footnote While many growth hormone–secreting pituitary adenomas can be treated with surgery, occasionally medical management is attempted using pegvisomant, which is a growth hormone receptor antagonist. In patients treated for 12 months, normal IGF levels are seen in 97% of patients, but tumor size remains the same. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 742.

Answer 98

A. Turcot’s syndrome **B. Garnder’s syndrome** C. McCune-Albright syndrome D. Paget’s disease ## Footnote Gardner’s syndrome is comprised of colonic polyposis, multiple cranial osteomas, and soft tis- sue tumors. Osteomas of the skull consist of oste- oid tissue within osteoblastic tissue with reactive bone formation around that region. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 775.

Answer 99

A. Osteoid osteoma **B. Hemangioma** C. Metastasis D. Multiple myeloma ## Footnote Hemangiomas of the skull can cause areas of skull protrusion with evidence of trabeculated bone on X-ray. During surgery they appear bluish in color underneath the pericranium. They should be excised completely to avoid recurrence. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 776.

Answer 100

**A. Diabetes insipidus** B. Seizures C. Papilledema D. Facial weakness ## Footnote The Hand-Schüller-Christian triad is a series ofclinical symptoms caused by an underlying diagnosis of Langerhans cell histiocytosis. When thisoccurs in the suprasellar region, a mass emanatingfrom the pituitary stalk can cause diabetes insipidus. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 777.

Answer 101

A. Turcot’s syndrome B. Garnder’s syndrome **C. McCune-Albright syndrome** D. Paget’s disease ## Footnote Fibrous dysplasia is a benign condition where bone is replaced by fibrous connective tissue, and it is seen commonly in McCune-Albright syndrome along with endocrine dysfunction, café au lait spots on one side of the midline, and precocious puberty. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 781.

Answer 102

A. Hyperventilation B. Mannitol C. Dexamethasone **D. Needle aspiration of cystic contents** ## Footnote While all of the above options are reasonable to decrease intracranial pressure, when a mass has a large cystic component, simple drainage of the cyst can lead to rapid decompression of the posterior fossa.

Answer 103

B. No ## Footnote Generally, the wall of the associated cyst cavity within a hemangioblastoma does not need to be resected, unless there is a portion that enhances. Removal of the enhancing mural nodule should lead to sufficient resection.

Answer 104

A. Yes ## Footnote Generally, the wall of the associated cyst cavity should be resected if it can be done safely. Certain pilocytic astrocytomas can have pseudocysts that are really more tumor tissue and attempts should be made to resect the wall if possible. Certainly any areas that are enhancing should be resected if it can be done safely.

Answer 105

A. Mamillary bodies B. Caudate head **C. Fornix** D. Thalamus ## Footnote When the endoscope is advanced through the foramen of Monro, care should be taken to avoid significant manipulation if possible given that the fornix can be easily compressed on the superior aspect of the foramen by a rigid endoscope. Further Reading: Torres-Corzo, Rangel-Castilla, Nakaji. Neuroendoscopic Surgery, 2016, page 232.

Answer 106

A. 1 to 2.5 cm **B. 3 to 4.5 cm** C. 5 to 5.5 cm D. 6 to 6.5 cm ## Footnote Approximately 3 to 4.5 cm of dominant temporal lobe can be resected safely. Further posterior and risk to language function increases. Further Reading: Baltuch, Villemure. Operative Techniques in Epilepsy Surgery, 2009, page 40.

Answer 107

A. 1 **B. 2** C. 3 D. 4 E. 5 ## Footnote The WFNS grade is a way to evaluate clinical symptoms after SAH. A patient with a GCS of 13 to 14 without major motor deficit would be considered a WFNS grade 2. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1163.

Answer 108

A. 0% B. 24% **C. 33%** D. 40% E. 50% ## Footnote The modified Fisher scale rates the amount and location of SAH to predict risk of vasospasm. Grade 1 is thin (< 3 mm) clot only with no IVH–24% risk. Grade 2 is thin (< 3 mm) clot with IVH–33% RISK. Grade 3 is thick (> 3 mm) clot with no IVH–33% risk, and grade 4 is thick clot with IVH–40% risk. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, page 471.

Answer 109

**A. 1.5%** B. 5% C. 25% D. 33% ## Footnote After aneurysmal rupture there is an approximately 1.5% per day risk of rebleeding up to 13 days postbleed. At 6 months there is a risk of 50%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1168.

Answer 110

A. Subclinical seizures B. Hyponatremia **C. Vasospasm** D. Intracerebral hemorrhage ## Footnote This patient is likely experiencing a vasospasm, which occurs usually between postbleed days 3 and 14. It is rare for vasospasm to occur < 3 days. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1178.

Answer 111

**A. Anterior communicating artery** ## Footnote Anterior communicating artery aneurysms are the most common location for intracranial aneurysms (30%). Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1191.

Answer 112

A. Anterior communicating artery **B. Posterior communicating artery** C. Carotid bifurcation D. Posterior inferior cerebellar artery ## Footnote Posterior communicating artery aneurysms classically present with a non-pupil sparing third nerve palsy (due to compression and not microvascular disease, which would be pupil sparing). While only 9% of posterior communicating artery aneurysms will present this way, given the location of the posterior communicating artery to the third nerve, it is a commonly tested subject. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1192.

Answer 113

A. Dissecting the dome free B. Releasing CSF **C. Proximal control** D. ICG administration ## Footnote Obtaining proximal control prior to dissecting the aneurysm or placing a clip. When proximal control is obtained, further dissection can take place. If the aneurysm ruptures, temporary clips can be applied to the areas of proximal control in order to decrease bleeding. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, page 1106.

Answer 114

A. Right inferior nasal quadrantanopsia **B. Right superior nasal quadrantanopsia** C. Right superior temporal quadrantanopsia D. Right inferior temporal quadrantanopsia ## Footnote Ophthalmic segment aneurysms can grow and cause compression of the optic nerve. Given that they will compress the nerve from the inferior temporal side, you would expect him to have an ipsilateral superior nasal quadrantanopsia. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1214.

Answer 115

**A. Falciform ligament** B. Tuburculum sellae C. Anterior clinoid process D. Middle clinoid process ## Footnote The falciform ligament is a dural fold overlying the superior aspect of the optic nerve. When an aneurysm pushes the optic nerve superiorly, compression can occur from above as the nerve is pressed against the falciform ligament. After an anterior clinoidectomy, opening of the falciform ligament can decompress the optic nerve. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1214.

Answer 116

A. Conventional cerebral angiogram B. MRI brain **C. CT head** D. Carotid ultrasound ## Footnote Occasionally patients can have bridging bone between the anterior and posterior clinoid processes, so called the “middle clinoid process.” If the surgeon is unaware of the presence of this middle clinoid process bridging bone, aggressive removal of the anterior clinoid process can lead to transection of the carotid artery as the bridging bone often encases the carotid artery to some degree. A CT scan of the head can rule out the presence of the middle clinoid bridging bone. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, page 17.

Answer 117

A. 2 **B. 3** C. 4 D. 5 E. 6 ## Footnote The Spetzler-Martin grading system applies to AVMs and takes into account size of the nidus (< 3 cm, 3–6 cm, > 6 cm), venous drainage (deep/ superficial), and location (eloquent/noneloquent cortex). The scale is 1 to 5. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1243.

Answer 118

A. 95% **B. 84%** C. 73% D. 69% E. 53% ## Footnote Based on the Spetzler-Martin grading system, grade 3 AVMs have an 84% chance of good outcome after surgical resection (grade 1 = 100%, grade 2 = 95%, grade 3 = 84%, grade 4 = 73%, grade 5 = 69%). Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1243.

Answer 119

A. 0% **B. 3.5%** C. 10% D. 17.5% E. 25% ## Footnote The approximate annual risk of hemorrhage for grade 1 to 3 AVMs is 3.5%. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1240.

Answer 120

B. False ## Footnote Many cavernous malformations of the brain are associated with developmental venous anomalies. It is important to remember that these venous channels can drain normal brain tissue and should not be resected to avoid risk of postoperative venous stroke. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1245.

Answer 121

A. True ## Footnote When cavernous malformations hemorrhage they can cause hemosiderin staining of the surrounding brain parenchyma which gives it a yellowish color. Many surgeons believe that this hemosiderin stained brain can be a seizure focus and should be resected if it can be done safely. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1250.

Answer 122

A. Hemorrhagic stroke B. Seizure C. Ischemic stroke **D. Pulsatile tinnitus** ## Footnote The vast majority of dural arteriovenous fistulae present with pulsatile tinnitus. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1251.

Answer 123

A. Direct cortical venous drainage without ectasia B. Direct cortical venous drainage with ectasia **C. Retrograde sinus and retrograde cortical venous drainage** D. Anterograde sinus and retrograde cortical venous drainage ## Footnote There are two major classification systems for dural arteriovenous fistulae, the Borden classification and the Cognard classification. The Cognard classification consists of type I (anterograde drainage through a sinus), type IIa (retrograde sinus drainage only), type IIb (anterograde sinus drainage with retrograde cortical venous reflux), type II a + b (retrograde sinus and retrograde cortical venous reflux), type III (direct cortical venous drainage without ectasia), type IV (direct cortical venous drainage with ectasia), and type V (direct drainage into spinal perimedullary veins). Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1254.

Answer 124

**A. Type II a + b** B. Type III C. Type II b D. Type II a ## Footnote Type II a + b (retrograde sinus and cortical venous reflux) carries the highest risk of hemorrhage, approximately 66%. Next is type IV with direct cortical venous drainage with ectasia, at 65%. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1254.

Answer 125

A. Hemorrhage B. Seizure **C. Heart failure** D. Ischemic stroke ## Footnote Vein of Galen malformations present in neonates with evidence of high output heart failure. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1256.

Answer 126

A. Intraparenchymal contusion B. Orbital blowout fracture C. Ophthalmic artery dissection **D. Carotid-cavernous fistula** ## Footnote Traumatic carotid-cavernous fistulae can occur after motor vehicle accidents or other intracranial trauma. They present with orbital pain, chemosis, proptosis, ophthalmoplegia, and visual loss. Patients should undergo vascular imaging and may require interventional or surgical treatment of the fistula. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1257.

Answer 127

B. False ## Footnote Radiation therapy damages cells by firing particles into an atom and releasing free electrons causing damage downstream. In fully oxygenated cells, oxygen combines with unpaired free electrons to form peroxides, which are more stable and lethal than free radicals, and therefore an oxygenated cell is more sensitive to damage by radiation therapy. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1566.

Answer 128

A. > 1 year **B. > 3 years** C. > 5 years D. > 7 years E. > 10 years ## Footnote Children less than 3 years of age are particularly sensitive to cranial radiation and can have severe developmental side effects. Children should be greater than 3 years of age to be eligible for cranial radiation. There may be demonstrable changes in IQ (decrease by 25 points) in children who receive radiation up to 7 years of age. Further Reading: Keating, Goodrich, Packer. Tumors of the Pediatric Central Nervous System, 2nd edition, 2013, page 138.

Answer 129

A. 1 cm or less **B. 3 cm or less** C. 5 cm or less D. 7 cm or less E. 10 cm or less ## Footnote Gamma knife radiosurgery can be useful for cranial masses, but should be reserved for patients with brain tumors that are 3 cm or less in maximum diameter. This size cutoff decreases the risk of harmful radiation side effects to surrounding brain structures. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1564.

Answer 130

A. 6 Gy **B. 10 Gy** C. 14 Gy D. 18 Gy E. 20 Gy ## Footnote Safe doses of radiation to the optic apparatus are generally thought to be 8 to 10 Gy. Doses beyond this can lead to visual loss. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1567. Lunsford, Sheehan. Intracranial Stereotactic Radiosurgery, 2016, page 52.

Answer 131

A. 10 Gy or less **B. 13 Gy or less** C. 16 Gy or less D. 19 Gy or less E. 22 Gy or less ## Footnote SRS doses for vestibular schwannomas have changed based on recent literature, and currently 12 to 13 Gy to the facial nerve seems to be a dose of radiation that causes good tumor control but greatly decreases the side effects to the seventh and eighth nerve. Further Reading: Lunsford, Sheehan. Intracranial Stereotactic Radiosurgery, 2016, page 150.

Answer 132

A. 6 Gy or less B. 8 Gy or less **C. 10 Gy or less** D. 12 Gy or less E. 15 Gy or less ## Footnote The lens of the eye can tolerate 10 Gy or less radiation with minimal side effects. Cataract formation will occur with doses up to 50 Gy. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1567 Lunsford, Sheehan. Intracranial Stereotactic Radiosurgery, 2016, page 52.

Answer 133

A. 10 to 20% B. 20 to 30% C. 30 to 40% **D. 40 to 50%** E. 50 to 60% ## Footnote At 10 years posttreatment, approximately 40 to 50% of patients who receive sellar radiation will experience hypopituitarism as a side effect from radiation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 744. Lunsford, Sheehan. Intracranial Stereotactic Radiosurgery, 2016, page 107.

Answer 134

A. < 2 Gy **B. 4 to 6 Gy** C. 7 to 9 Gy D. 10 to 12 Gy E. 13 to 15 Gy ## Footnote Based on current literature, the mean safe radiation dose to the cochlea is considered to be approximately 4.2 Gy, but has also been shown to range from 4 to 6 Gy. There is some controversy on this topic currently, but based on data available, doses from 4 to 6 Gy should be considered optimal. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1570.

Answer 135

A. 10 Gy B. 18 Gy **C. 24 Gy** D. 30 Gy E. 40 Gy ## Footnote For tumors that are 10 to 20 mm, SRS doses up to 24 Gy can be used with acceptable risk of side effects. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1570.

Answer 136

A. 10 Gy **B. 18 Gy** C. 24 Gy D. 30 Gy E. 40 Gy ## Footnote For tumors that are 21 to 30 mm, SRS doses up to 18 Gy can be used with acceptable risk of side effects. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1570.

Answer 137

A. Proton-beam radiation B. Stereotactic radiosurgery **C. Whole brain radiation** D. Observation ## Footnote Current literature supports the use of whole brain radiation in patients who have undergone resection of a cerebral metastasis. Doses up to 50 Gy have been shown to control > 90% of micrometasases, but at this dose there is a very high chance of early radiation side effects. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 808.

Answer 138

A. 5 or less **B. 10 or less** C. 15 or less D. 20 or less ## Footnote Based on current studies, up to 10 concurrent cerebral metastases can be treated with stereotactic radiosurgery with good outcome and low risk of side effects. There are surgeons who feel that even this number can be safely extended, research is pending. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1568.

Answer 139

A. < 1 week B. < 1 month C. < 1 year **D. < 3 years** E. > 5 years ## Footnote Stereotactic radiosurgery can be a good option for low grade AVMs with a well formed nidus that border eloquent cortex. Radiation works by causing damage to the endothelium and ultimately causing fibrosis. This process can take 2 to 3 years to develop, so risk of hemorrhage needs to be discussed with the patient over that treatment timeframe. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1568.

Answer 140

A. 14 to 16 Gy B. 18 to 20 Gy **C. 23 to 25 Gy** D. 29 to 31 Gy ## Footnote Current literature suggests that 23 to 25 Gy radiation doses to AVMs lead to high rates of obliteration with low risk of complications. Higher radiation doses have been associated with an increased risk of complications and no significant improvement in obliteration rates. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1568.

Answer 141

A. 10 to 20% B. 30 to 40% C. 50 to 60% **D. 70 to 80%** E. 90 to 100% ## Footnote Current literature suggests that 70 to 80% of all AVMs treated with stereotactic radiosurgery may achieve complete obliteration by 2 to 3 years after treatment. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 1568.

Answer 142

A. 25% B. 45% **C. 65%** D. 85% ## Footnote While up to 86% of patients will experience a decrease in their pain after SRS for TGN, the long term pain free rate is approximately 65%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 485.

Answer 143

A. Intracerebral hemorrhage B. Seizures C. Headaches **D. Dementia** ## Footnote Dementia is the main complication from whole brain radiation after use for intracranial metastases. Symptoms can develop as quickly as 1 year after WBRT is performed. Incidence has been shown to be higher when patients receiving doses of 25 to 39 Gy receive those doses in fractionations that are > 300c Gy Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1561.

Answer 144

**A. 8 Gy** B. 15 Gy C. 22 Gy D. 30 Gy ## Footnote Emergency radiation can be delivered to radiosensitive spine tumors when there is evidence of compression. In many circumstances, an initial dose of 8 Gy will be given to shrink the tumor, followed by further fractionated radiation after the acute situation has resolved. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1562.

Answer 145

A. 10 Gy in 10 fractions B. 20 Gy in 10 fractions **C. 30 Gy in 10 fractions** D. 40 Gy in 10 fractions ## Footnote Radiation to the spine for metastatic disease in the setting of radiosensitive tumors is often administered at a dose of 30 Gy delivered over 10 fractions. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1562.

Answer 146

A. 5% B. 50% **C. 75%** D. 100% ## Footnote While TGN can be treated medically, approximately 75% of patients will require a procedure directed at treating the TGN. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 479.

Answer 147

**A. Anesthesia dolorosa** B. Worsened facial pain C. Brainstem ischemic stroke D. Seizure ## Footnote Anesthesia dolorosa is a feared complication of intentional damage to the trigeminal nerve. It occurs after damage to the V1 segment of the nerve, and can lead to anesthesia of the cornea, causing patients to get recurrent corneal abrasions. Significant care should be taken to avoid injuring the V1 segment. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 479.

Answer 148

A. Start carbamazepine **B. MRI brain with FIESTA sequences** C. Right sided microvascular decompression D. Observation ## Footnote This patient appears to have symptoms consistent with trigeminal neuralgia. Initially, imaging of the brain should be performed to rule out mass lesions or evidence of multiple sclerosis. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 479.

Answer 149

**A. Start carbamazepine** B. Start oxycodone C. Right sided microvascular decompression D. Right sided percutaneous trigeminal rhizotomy ## Footnote This patient appears to have symptoms consistent with trigeminal neuralgia. Initially, imaging of the brain should be performed to rule out mass lesions or evidence of multiple sclerosis. Following this, a trial of medical management utilizing carbamazepine 100 mg BID is a reasonable option. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 479.

Answer 150

A. 30% B. 50% **C. 70%** D. 90% ## Footnote At 10 years, microvascular decompression has a pain free rate of 70%. It is an excellent option for patients who can tolerate a small craniotomy and have a life expectancy of longer than 5 years. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 479.

Answer 151

A. Urine osmolality B. Serum sodium **C. Fluid status** D. Urine output ## Footnote SIADH and CSW are both conditions that cause hyponatremia and can be seen after aneurysmal rupture. It is important to determine the difference between the two as treatment is different. CSW causes patients to be hypovolemic whereas in SIADH patients are euvolemic. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 110.

Answer 152

A. Hypertonic saline **B. Fluid restriction** C. DDAVP D. Demeclocycline ## Footnote In SIADH, patients are euvolemic or hypervolemic and hyponatremic. In a patient who can tolerate PO intake and is conscious, fluid restriction is a good initial step in management assuming the hyponatremia is not severe. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 118.

Answer 153

A. Furosemide B. Hydrocortisone C. DDAVP **D. Demeclocycline** ## Footnote Demeclocycline is a tetracycline antibiotic that has side effects including antagonism of ADH. It can be used for medical management of SIADH if fluid restriction is not normalizing the sodium. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 118.

Answer 154

A. Furosemide **B. Fludrocortisone** C. DDAVP D. Demeclocycline ## Footnote Fludrocortisone acts directly on renal tubules to increase sodium absorption and can be a useful medication adjunct when treating cerebral salt wasting. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 119.

Answer 155

**A. Normal saline infusion** B. Fluid restriction C. DDAVP D. Demeclocycline ## Footnote In cerebral salt wasting, patients are hypovolemic and hyponatremic. Fluid resuscitation with normal saline at 100 to 125 mL/hr should be instituted in an attempt to normalize fluid status. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 119.

Answer 156

A. Hyponatremia **B. Severe dehydration** C. Coma D. Status epilepticus ## Footnote The main complication of untreated diabetes insipidus is severe dehydration Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 120.

Answer 157

A. 25% B. 55% **C. 85%** D. 100% ## Footnote Approximately 85% capacity to secrete ADH must be lost before symptoms of DI will be evident. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 120.

Answer 158

**A. Drink to thirst** B. DDAVP administration C. Salt tablets D. Hypertonic saline infusion ## Footnote In an awake, conscious and ambulatory patient with mild diabetes insipidus, sodium levels should be monitored, but patients should be allowed to drink to thirst. They are often able to effectively manage their sodium via thirst mechanisms. Utilization of DDAVP occurs in unconscious patients or those who cannot adequately compensate using standard thirst mechanisms. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 123.

Answer 159

A. > 2 µg/kg/min B. > 5 µg/kg/min **C. > 10 µg/kg/min** D. > 15 µg/kg/min ## Footnote At doses from 2-10 µg/kg/min, dopamine is a positive inotrope, but remember that at least 25% of IV dopamine is converted to norepinephrine, so at doses > 10 µg/kg/min you are essentially giving norepinephrine and the alpha/beta/dopaminergic receptors are all activated. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 128.

Answer 160

A. 12 hours B. 24 hours C. 48 hours **D. 72 hours** ## Footnote Dobutamine increases cardiac output by positive inotropy, but patients will exhibit tachyphylaxis after approximately 72 hours of administration. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 128.

Answer 161

A. < 2 days B. < 1 week **C. < 3 weeks** D. < 6 months E. 1 year ## Footnote Generally speaking, patients who are on daily steroid medications should receive GI prophylaxis to prevent steroid induced ulcers after they have been on the medication for 3 weeks or longer. Acutely hospitalized patients or postoperative patients on steroids should be on GI prophylaxis as the stress of the hospitalization can lead to stress ulcer formation Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 129.

Answer 162

A. 1 to 5K **B. 5 to 10K** C. 10 to 15K D. 15 to 20K ## Footnote One unit of platelets (out of the standard six pack) will raise the platelet count approximately 5 to 10K. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 155.

Answer 163

**A. 10K** B. 30K C. 50K D. 75K ## Footnote In the absence of evidence of bleeding, platelets should be transfused prophylactically when the count drops to 10K. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 154.

Answer 164

A. 1 mg protamine/10 u heparin **B. 1 mg protamine/100 u heparin** C. 1 mg protamine/1,000 u heparin D. 1 mg protamine/10,000 u heparin ## Footnote Protamine sulfate can be used to reverse the effects of unfractionated heparin, and should be administered in doses of 1 mg protamine/100 u heparin. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 158.

Answer 165

A. Immediately **B. 4 hours** C. 12 hours D. 24 hours ## Footnote Idarucizumab (Praxbind) is an effective reversal agent for the direct thrombin inhibitor Dabigatran (Pradaxa). It reverses the effects within 4 hours and lasts for 24 hours. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 165.

Answer 166

A. Hyperkalemia B. Seizure **C. Malignant hyperthermia** D. Respiratory failure ## Footnote Malignant hyperthermia can occur after anesthetic use of volatile anesthetics, specifically halothane, or muscle relaxants such as succinylcholine. It is characterized by rigidity, tachycardia, tachypnea and severe fever. Further Reading: Keating, Goodrich, Packer. Tumors of the Pediatric Central Nervous System, 2nd edition, 2013, page 131.

Answer 167

A. Benzodiazepines B. Propofol **C. Dantrolene** D. Desmopressin ## Footnote Malignant hyperthermia can occur after anesthetic use of volatile anesthetics, specifically halothane, or muscle relaxants such as succinylcholine. It is characterized by rigidity, tachycardia, tachypnea and severe fever. It should be treated with administration of dantrolene. Further Reading: Keating, Goodrich, Packer. Tumors of the Pediatric Central Nervous System, 2nd edition, 2013, page 131.

Answer 168

A. Nicotinic **B. Ryanodine** C. NMDA D. GABA ## Footnote Malignant hyperthermia can occur after anesthetic use of volatile anesthetics, specifically halothane, or muscle relaxants such as succinylcholine. It is characterized by rigidity, tachycardia, tachypnea and severe fever. It should be treated with administration of dantrolene. It is thought to occur in some cases due to genetic defects in the ryanodine receptor on the sarcoplasmic reticulum. Further Reading: Keating, Goodrich, Packer. Tumors of the Pediatric Central Nervous System, 2nd edition, 2013, page 131.

Answer 169

A. 6% B. 11% **C. 17%** D. 23% E. 28% ## Footnote Based on NASCET, in patients with symptomatic high grade stenosis who undergo CEA with an acceptable perioperative risk, the reduction in stroke rate is 17% at 18 months. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1290. Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 96.

Answer 170

A. 1% or less **B. 3% or less** C. 5% or less D. 7% or less E. 10% or less ## Footnote Current literature suggests that you should have a 3% or less overall complication rate to justify performing a carotid endarterectomy. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1292. Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 96.

Answer 171

A. EEG **B. CT angiogram** C. MRI D. Bedside decompression ## Footnote This patient is experiencing return of her preoperative symptoms after CEA. It is possible that the CEA site is undergoing thrombosis and should be emergently evaluated with a CT angiogram to determine patency of the vessel. If occluded, she should return to the OR for re-opening and treatment of the occlusion. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1293. Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 96.

Answer 172

A. Pain medication administration B. CT angiogram **C. Blood pressure control** D. Operative exploration ## Footnote This patient is likely experiencing cerebral hyperperfusion syndrome given that blood flow to the ipsilateral hemisphere has now greatly increased. This is a controversial area, but close blood pressure control can help decrease the symptoms of cerebral hyperperfusion syndrome. Imaging should be obtained as well to ensure that no hemorrhage has occurred. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1293.

Answer 173

**A. Hypoglossal palsy** B. Spinal accessory palsy C. Vagus palsy D. Glossopharyngeal palsy ## Footnote The distal hypoglossal nerve is often seen during the dissection for a carotid endarterectomy and a postoperative palsy has been reported to be as high as 8% in some series. Care should be taken to avoid damaging the hypoglossal nerve during the dissection. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1293.

Answer 174

A. CT Angiogram **B. Bedside decompression** C. Intubation D. Oxygen administration ## Footnote This patient has an obvious arteriotomy closure disruption and it is causing tracheal deviation and respiratory compromise. While you may think intubation would be the initial management option, it can be difficult or impossible in patients with severe tracheal deviation, so bedside decompression of the clot should occur immediately, followed by intubation and return to the OR. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1294.

Answer 175

A. 1 week **B. 2 weeks** C. 3 weeks D. 1 month ## Footnote Pooled analysis of the symptomatic carotid stenosis trials have demonstrated that there is a benefit for patients who receive a CEA within 2 weeks of stroke compared to those patients who had a CEA at greater than 2 weeks. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1291.

Answer 176

A. Superiority B. Nonsuperiority C. Inferiority **D. Noninferiority** E. Worsened outcomes ## Footnote The CREST trial demonstrated non-inferiority of carotid angioplasty and stenting to open carotid endarterectomy. In many practices, surgeons utilize carotid angioplasty and stenting in patients with high-riding carotid bifurcations or very difficult appearing stenosis that might have a higher rate of operative complications. Further Reading: Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 96.

Answer 177

A. Anterior cortex only **B. Anterior and posterior cortex** C. Anterior/posterior cortices and pedicles D. Anterior/posterior cortices, pedicles and posterior ligamentous complex ## Footnote A spinal fracture is considered a burst fracture when both the anterior and posterior cortices of the vertebral body are violated. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 178

A. Compression fracture **B. Burst fracture** C. Chance fracture D. Fracture dislocation ## Footnote A spinal fracture is considered a burst fracture when both the anterior and posterior cortices of the vertebral body are violated. This CT scan demonstrates a burst fracture of the lumbar spine. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 179

A. Observation and pain control only **B. TLSO bracing** C. Decompressive laminectomy D. Fusion ## Footnote In most patients with asymptomatic burst fractures and preserved alignment, bracing is a viable option. Patients should be fitted with a TLSO brace andbaseline X-rays should be obtained. Follow-up X-raysin 6 weeks can be obtained to ensure no change inalignment. This treatment technique is based onthe Kirkham Wood study evaluating asymptomaticburst fractures managed with bracing alone. Somesurgeons are avoiding bracing completely in thesepatients, and this is a somewhat controversial issuethat is still undergoing further research. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 180

**A. Anterior cortex only** B. Anterior and posterior cortex C. Anterior/posterior cortices and pedicles D. Anterior/posterior cortices, pedicles and posterior ligamentous complex ## Footnote A compression fracture of the spine occurs when imaging demonstrates violation of the anterior cortex only. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 181

**A. Compression fracture** B. Burst fracture C. Chance fracture D. Fracture dislocation ## Footnote A spinal fracture is considered a compression fracture when the anterior cortex is violated but other aspects of the spine remain intact. This X-ray demonstrates a compression fracture. urther Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 182

**A. Flexion compression** B. Pure axial load C. Flexion distraction D. Shear ## Footnote This image demonstrates a compression fracture, evidenced by violation of only the anterior cortex. This injury occurs via a flexion compression loading mechanism with the axis of rotation located within the anterior vertebral body. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 183

A. Flexion compression **B. Pure axial load** C. Flexion distraction D. Shear ## Footnote This image demonstrates a burst fracture (violation of both the anterior and posterior cortices). This injury is caused by a pure axial load mechanism. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 184

A. Flexion compression B. Pure axial load **C. Flexion distraction** D. Shear E. Extension distraction ## Footnote This image demonstrates a three column pure bony injury, often referred to as a Chance fracture after the physician G.Q. Chance in 1948. It is caused by a flexion distraction force mechanism where the axis of rotation is anterior to the vertebral body. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1004.

Answer 185

A. Flexion compression B. Pure axial load C. Flexion distraction **D. Shear** ## Footnote This image demonstrates a severe spinal cord fracture caused by shear injury to the spinal column. It appears to be both a bony and soft tissue injury causing a fracture dislocation of the spine and certain ASIA A spinal cord injury. The forces applied to the spine in order to achieve this level of dislocation are significant. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1004.

Answer 186

A. Flexion compression B. Pure axial load **C. Extension distraction** D. Shear ## Footnote This image demonstrates a three column spine fracture in a patient with evidence of ankylosis of the spine. While these patients form bone easily, the bone within the vertebral body is brittle and fractures easily. This fracture was caused by an extension distraction mechanism with the axis of rotation within the posterior spinal elements. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1004.

Answer 187

A. T6-7 B. T9-10 **C. T12-L1** D. L3-4 ## Footnote Burst fractures are caused by pure axial load mechanisms and most often occur in the T12-L1 region since the T12-L1 vertebral bodies are the most centered in the midline between the lordotic lumbar spine and kyphotic thoracic spine. It is in this region where the force vector in a pure axial load mechanism is applied directly through the center of the vertebral body causing a dispersion fracture mechanism leading to disruption of the anterior and posterior vertebral cortices causing a burst fracture to occur. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 188

**A. Operative** B. Nonoperative C. “Gray zone” ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. In this setting, the patient gets 2 points for burst fracture, 2 points for indeterminate ligamentous status and 2 points for nerve root injury, leading to a score in the operative treatment range. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 189

**A. Operative** B. Nonoperative C. “Gray zone” ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. In this setting, the patient gets 2 points for burst fracture, 0 points for PLC integrity and 3 points for cauda equina syndrome, leading to an operative management. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 190

A. Operative **B. Nonoperative** C. “Grey zone” ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. In this setting, the patient gets 2 points for burst fracture, 0 points for PLC integrity and 0 points for full strength exam leading to nonoperative management. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 191

A. 1 **B. 2** C. 3 D. 4 E. 5 ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. 2 points are assigned for complete spinal cord injury, in comparison to 3 points assigned for cauda equina syndrome and incomplete spinal cord injury. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 192

A. 1 B. 2 **C. 3** D. 4 E. 5 ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. 3 points are assigned for translational/rotational injury morphology. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 193

A. 1 B. 2 **C. 3** D. 4 E. 5 ## Footnote The TLICS score is becoming more common for evaluation and initial management of thoracolumbar traumatic injuries. Points are assigned based on fracture morphology, PLC integrity and presenting symptoms. 3 points are assigned for definite injury to the posterior ligamentous complex. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1007.

Answer 194

A. Anterior column **B. Middle column** C. Posterior column D. Ligamentous complex ## Footnote In the 3-column model of Denis, the posterior vertebral body is located within the middle column. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1002.

Answer 195

A. Anterior column B. Middle column **C. Posterior column** D. Ligamentous complex ## Footnote In the 3-column model of Denis, the facet joints are located within the posterior column. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1002.

Answer 196

A. Stable ## Footnote Isolated transverse process fractures of the thoracolumbar spine are generally considered stable when not associated with other major injuries and can be managed expectantly. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 1003.

Answer 197

A. Type I B. Type II **C. Type III** D. Type IV ## Footnote There are three types of odontoid fractures, and type III odontoid fractures extend at the base of the odontoid process slightly into the body of C2. If there is not significant distraction across the fracture, these fractures are usually considered stable compared to type I and type II injuries. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 978.

Answer 198

A. Type I **B. Type II** C. Type III D. Type IV ## Footnote This plain X-ray demonstrates a type II odontoid fracture. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 979.

Answer 199

A. 5% B. 20% **C. 30%** D. 50% E. 70% ## Footnote Approximately 30% of type II odontoid fractures will exhibit non-union at long-term follow-up. Specific rates depend on fracture characteristics including displacement and angulation, but 30% is a good rule to consider when deciding management. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 980.

Answer 200

**A. 3 mm** B. 6 mm C. 9 mm D. 12 mm ## Footnote The generally accepted normal value for ADI is 3 mm or less. More than 3 mm and the integrity of the transverse ligament should be evaluated to determine stability. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 970.

Answer 201

A. Type II dens fracture B. Traumatic spondylolisthesis of the axis C. Jefferson fracture **D. Atlanto-occipital disassociation** ## Footnote These images demonstrate AOD as evidenced by the increased interval between the occiput and atlas. It is clearly very unstable, and often times this is a fatal injury. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 964.

Answer 202

A. 1 B. < 1 **C. > 1** D. 0 ## Footnote The powers ratio is used to diagnose AOD. It is measured by the length of a line drawn from the basion to the posterior arch of C1 divided by a line drawn from the opisthion to the anterior arch of C1. A ratio of > 1 is suggestive of AOD. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 964.

Answer 203

A. Type I B. Type II **C. Type IIa** D. Type III E. Type IV ## Footnote The type IIa Hangman’s fracture exhibits distraction and angulation and should not be put in traction as there is risk of causing spinal cord injury in traction. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, page 975.

Answer 204

A. Type I B. Type II C. Type IIa **D. Atypical** ## Footnote This axis fracture is one of the atypical variety given that the fracture occurs through the base of the C2 vertebral body and the posterior cortex of the body is left in place rather than fracturing through the pedicles of C2. This fracture type should be evaluated closely as the spike of remaining vertebral body can cause the spinal cord to be draped over the shard anteriorly and cause spinal cord injury. Further Reading: Jallo, Vaccaro. Neurotrauma and Critical Care of the Spine, 2009, page 133.

Answer 205

A. 5 degrees **B. 11 degrees** C. 16 degrees D. 21 degrees ## Footnote Type IIa fractures of the axis are dangerous due to distraction and angulation. They should be recognized as they are a subset of fractures that should not be put in traction as this can worsen the injury type. Generally, 11 degrees of angulation should alert the neurosurgeon to the possible presence of a type IIa injury. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 975.

Answer 206

B. Unstable ## Footnote This imaging demonstrates an elevated ADI both in the baseline X-ray and an increase in the ADI with flexion. This indicates likely transverse ligament injury. The TL is a stabilizing ligament and in the presence of injury, fusion should be considered as the atlantoaxial joint is likely unstable. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 971.

Answer 207

A. 10 mm B. 13 mm **C. 17 mm** D. 21 mm E. 25 mm ## Footnote The normal cervical spinal canal is roughly 17 mm. When the AP diameter is 13 or less, congenital stenosis is likely present. Further Reading: Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 457.

Answer 208

**A. 10 mm** B. 13 mm C. 17 mm D. 21 mm ## Footnote The normal cervical spinal cord is roughly 10 mm. Further Reading: Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, page 457.

Answer 209

A. Collar immobilization and observation B. Posterior C3-7 laminectomy C. Halo placement **D. MRI** ## Footnote This patient may have suffered spinal cord injury without radiographic abnormality, but that cannot be fully determined until an MRI has been performed. The MRI will look for signal change within the spinal cord as well as the presence of any ligamentous injury. The patient should remain in a cervical collar until the results from the MRI are obtained. Further Reading: Greenberg. Handbook of neurosurgery. 8th edition. 2016, page 999.

Answer 210

**A. Jumped facets** B. Traumatic spondylolisthesis of the axis C. Jefferson fracture D. Tear drop fracture E. Atlanto-occipital dislocation ## Footnote This axial CT scan demonstrates jumped facets. This patient has a fracture dislocation with jumped facets. There could be an underlying spinal cord injury and reduction with closed traction should be performed. If the patient is awake and responsive, an MRI may not be necessary before traction is implemented as the patient has a reliable exam to follow. However, if the patient is unconscious, an MRI may be beneficial to rule out a large disc herniation that could be worsened with closed reduction. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 993.

Answer 211

**A. Traction** B. Collar immobilization/observation C. MRI scan D. Posterior decompression/fusion ## Footnote This axial CT scan demonstrates a unilateral jumped facet. The superior articulating process on the left is dorsal to the inferior articulating process and there is evidence of rotation. This patient should likely be placed in traction. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 993.

Answer 212

**A. Traction** B. Collar immobilization/observation C. MRI scan D. Posterior decompression/fusion ## Footnote This patient is awake and has a neurologic exam that can be followed. Traction is safe to perform in this patient without an MRI scan first as you are able to follow her exam after addition of weight. If any change in the neuro exam occurs, the weight can be removed and the exam re-confirmed. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, page 237.

Answer 213

A. Traction B. Collar immobilization/observation **C. MRI scan** D. Posterior decompression/fusion ## Footnote This patient is intubated and sedated and therefore is not able to provide an exam during traction. An MRI should be performed first to rule out the presence of a large disc fragment anteriorly that could compress the cord. Traction is safe to perform in a patient without an MRI scan if you are able to reliably follow a neurologic exam in an awake patient. If any change in the neuro exam occurs, the weight can be removed and the exam re-confirmed. With obtunded/intubated patients, an MRI should be performed first. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, page 237.

Answer 214

A. 1 lb B. 5 lbs **C. 10 lbs** D. 20 lbs E. 25 lbs ## Footnote Generally, when applying cervical traction, 10LBS of weight can be applied per level, but fluoroscopy should be utilized after the addition of any weight to determine if any change has occurred. If the patient is awake, an exam should be performed as well after the addition of any weight. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, page 237.

Answer 215

A. Apical ligament B. Alar ligaments **C. Transverse ligament** D. Atlanto-occipital membrane ## Footnote The rule of Spence is calculated be measuring the displacement of the C1 lateral masses on the C2 joints. If the total overhang of the C1 lateral masses on the C2 joints is > 7 mm, disruption of the transverse ligament should be suspected. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 970.

Answer 216

A. 4 mm **B. 7 mm** C. 11 mm D. 15 mm E. 20 mm ## Footnote The rule of Spence is calculated be measuring the displacement of the C1 lateral masses on the C2 joints. If the total overhang of the C1 lateral masses on the C2 joints is > 7 mm, disruption of the transverse ligament should be suspected. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 970.

Answer 217

A. Non-contrast lumbar CT B. Contrast enhanced lumbar CT C. Lumbar spine MRI without gadolinium **D. Lumbar spine MRI with gadolinium** ## Footnote This patient likely has a recurrent herniated lumbar disk and should be evaluated with a gadolinium enhanced lumbar spine MRI. Scar tissue will enhance homogeneously while a recurrent disk may peripherally enhance but will not demonstrate homogeneous enhancement. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1042.

Answer 218

A. 50% B. 70% **C. 85%** D. 100% ## Footnote Approximately 85% of patients with a herniated lumbar disc will improve with 6 weeks of nonoperative management, thus an initial period of non-surgical management should be attempted before surgical decompression is considered. This does not include patients with progressive weakness or cauda equina syndrome. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1050.

Answer 219

A. Sensory loss **B. Progressive weakness** C. Acute severe pain D. Positive straight leg raise ## Footnote While many patients with a HLD will improve with non-operative management, patients with progressive weakness of the lower extremity should be considered for more rapid intervention given the possibility of preserving or improving motor strength in the acute phase. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1050.

Answer 220

A. Saddle anesthesia B. Motor weakness **C. Urinary retention** D. Bowel incontinence ## Footnote Urinary retention is the most consistent finding in CES, and has a sensitivity of approximately 90%. Patients can be evaluated with post void residual measurement. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1050.

Answer 221

A. 25% **B. 50%** C. 75% D. 100% ## Footnote Urinary retention is the most consistent finding in CES, and has a sensitivity of approximately 90%. Patients can be evaluated with post void residual measurement. In patients with urinary retention and confirmed CES, only 50% will return to full bladder function. When full saddle anesthesia develops, few patients will return to normal bladder function Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1051.

Answer 222

A. ~ 25% B. ~ 50% **C. ~ 75%** D. ~ 100% ## Footnote Approximately 73% of patients will be free of leg pain 1 year after surgery for a herniated lumbar disc. At 5 to 10 years the number drops to 62%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1057.

Answer 223

A. 1% at 10 years **B. 4% at 10 years** C. 7% at 10 years D. 10% at 10 years ## Footnote According to current literature, the rate of re- current disc herniation at the same level on either side is approximately 4% at 10 years, with 1/3rd of those patients experiencing the recurrence within the 1st year postoperation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1061.

Answer 224

A. 0 mm **B. 2 mm or less** C. 5 mm or less D. 10 mm or less ## Footnote ACDFs should be evaluated in follow-up with flexion/extension films. To evaluate for a pseudoarthrosis, measurements should be taken between the spinous processes at that level. Movement greater than 2 mm between flex/ex films should make you consider that a pseudoarthrosis is present at that level. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1077.

Answer 225

A. Spinous process B. Pedicle **C. Superior articulating process** D. Inferior articulating process ## Footnote The superior articulating process of the lumbar spine makes up the roof of the gutter, or lateral recess and often causes nerve root impingement. When there is abnormal motion, the facets hypertrophy and this, in the setting of redundant ligamentum flavum and bulging discs, stenosis and nerve root impingement occurs. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1097.

Answer 226

**A. 3 mm or greater** B. 5 mm or greater C. 7 mm or greater D. 9 mm or greater ## Footnote When measured on CT scans of the lumbar spine, the normal lateral recess height is 3 mm or greater. A patient could be symptomatic at a height of 3 mm if other pathology is present, i.e., ligamentum flavum hypertrophy or disc bulging. In the absence of these findings, 3 to 4 mm should be adequate height that does not lead to symptoms when in extension. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1102.

Answer 227

A. L3 **B. L4** C. L5 D. S1 E. S2 ## Footnote In spondylolisthesis, the nerve root of the upper involved vertebral body is usually compressed. This is due to the superior articulating process of the vertebral body below as well as retropulsion of disc material. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1098.

Answer 228

A. I, II, III, IV **B. II, III, IV** C. I, IV D. IV only ## Footnote A fusion should be strongly considered in any cases of spondylolisthesis beyond grade I based on the Meyerding classification. Flexion extension plain films should also be obtained to determine whether or not there is worsening of the spondylolisthesis in flexion. This finding would lead you to more strongly consider a fusion operation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1104.

Answer 229

A. L4-5 spondylolisthesis **B. Atlantoaxial subluxation** C. Thoracic disc herniation D. Ankylosing spondylitis ## Footnote 25% of patients with rheumatoid arthritis will exhibit exaggerated movement of the atlantoaxial joint, occasionally manifesting as frank instability and subluxation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1134.

Answer 230

**A. Chiari I malformation** B. Chiari II malformation C. Chiari III malformation D. Chiari IV malformation ## Footnote 70% of spinal cord syrinxes are associated with chiari I malformations. They can also be seen after trauma to the spinal cord. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1144.

Answer 231

**A. Observation/serial imaging** B. Percutaneous drainage C. Syringosubarachnoid shunt D. Posterior fossa decompression ## Footnote Asymptomatic incidentally discovered spinal cord syrinxes should be initially observed with serial imaging over several years. If there is growth or symptoms arise, treatment can be considered. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1147.

Answer 232

**A. Dorsal root entry zone** B. Midline C. Anterior to the dentate ligament D. Dorsal column ## Footnote The shunt catheter should be placed in the dorsal root entry zone. This is different from spinal cord tumors which should be approached through a midline myelotomy. In the case of a syrinx, the DREZ may be the thinnest portion of the spinal cord and sensory deficits from the syrinx may already be present, not placing any further neurologic function at risk. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1147.

Answer 233

A. 13% B. 37% **C. 54%** D. 86% ## Footnote According to current literature, clinical stabilization is seen in 54% of patients who receive a syringosubarachnoid shunt for spinal cord syrinx at 10-year follow-up. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1147.

Answer 234

A. Methotrexate **B. Hydrocortisone** C. Octreotide D. Oxycodone ## Footnote Spinal epidural lipomatosis is associated with prolonged use of exogenous steroids. It leads to overgrowth of epidural fat which can be compres- sive to the spinal cord. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1150.

Answer 235

**A. Weight loss** B. Epidural steroid injection C. Lumbar laminectomy D. Lumbar laminectomy and fusion ## Footnote In obese patients not on steroid therapy, an initial trial of weight loss may reverse the symptoms and imaging findings of spinal epidural lipomatosis. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition, 2016, page 1150.

Answer 236

A. > 3 mm B. > 5 mm **C. > 7 mm** D. > 9 mm ## Footnote It has been suggested that a width of 7 mm or greater epidural fat should be present to make the diagnosis of spinal epidural lipomatosis. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 1150.

Answer 237

**A. 2.9%** B. 6.7% C. 12.3% D. 16.5% ## Footnote According to the literature, symptomatic adjacent segment disease occurs at roughly 2.9%/year after ACDF. The 10-year overall rate has been found to be 25.6%. Further Reading: Hilibrand et al. Radiculopathy and myelopathy at segments adjacent to ACDF. JBJS 1999.

Answer 238

A. Osteogenesis **B. Osteoconduction** C. Osteoinduction D. Osteointegration ## Footnote There are three main principles of bone formation, osteogenesis, osteoinduction, and osteoconduction. Osteoconduction describes the placement of a solid matrix/scaffold for bone to form within. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 626.

Answer 239

A. 50-50 B. 20-80 **C. 80-20** D. 60-40 ## Footnote The rule of Harms suggests that 80% of the axial load bearing capacity is borne by the anterior column, while 20% is borne by the posterior column. This becomes important when considering spinal fusion surgery and need for anterior or posterior fusion procedures. Further Reading: Harbaugh et al. Neurosurgery knowledge update. 2015, page 627.

Answer 240

A. 80% B. 85% C. 90% **D. 95%** ## Footnote According to a series of 140 patients followed to 5 years, the rate of fusion for single level ACDF was 97%. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 526.

Answer 241

A. No midline tenderness B. No distracting injury **C. Presence of a cervical collar** D. Awake/interactive patient ## Footnote The nexus criteria were developed to decrease unnecessary C-spine imaging. It includes no midline tenderness, no focal neurologic deficit, normal alertness, no intoxication and no painful distracting injury. When all of these are present, imaging can be avoided with a negative predictive value of 99.8% Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 503.

Answer 242

A. Degree of comminution **B. Posterior ligamentous complex injury** C. Fracture apposition D. Degree of kyphosis ## Footnote The McCormack load sharing classification was developed to help surgeons decide whether or not a short segment fusion would be sufficient to fix certain types of thoracolumbar fractures. The classification takes into account degree of fracture comminution, fracture fragment apposition and degree of kyphosis in determining the length of the construct. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 503.

Answer 243

B. False ## Footnote While this remains an area of some controversy, multiple studies have failed to demonstrate benefit from the administration of high dose methylprednisolone in the setting of cervical SCI. Current guidelines do not recommend the use of steroids in this setting. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 505.

Answer 244

A. 70 mm Hg **B. 85 mm Hg** C. 100 mm Hg D. 115 mm Hg ## Footnote Most surgeons and intensivists support MAP augmentation after spinal cord injury. Often the MAP goals are 85-90 mm Hg. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 505.

Answer 245

A. A **B. B** C. C D. D ## Footnote The AO classification system is designed to describe fracture morphology. Type A injuries are often compression injuries, Type B are distraction injuries and Type C are rotational. An easy way to remember this is Type A = Axial (loading), Type B = Bending (forward or backward with distraction) and Type C = Circular (translational injuries). There is no type D. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 508.

Answer 246

A**. No difference between groups** B. Significant benefit of surgery out to 4 years C. Significant benefit of conservative management out to 4 years D. No improvement with either management strategy ## Footnote The SPORT trial was used to look at outcomes after various spine management strategies. For lumbar disc herniations, there was no difference between conservative and surgical management out to 4 years of follow-up on intention-to-treat analysis, however there was a 22% cross-over between groups, a common criticism of this study Further Reading: Weinstein et al. Surgical versus nonoperative treatment for lumbar disc herniation. Spine, 2008.

Answer 247

A. No difference between groups **B. Significant benefit of surgery out to 4 years** C. Significant benefit of conservative management out to 4 years D. No improvement with either management strategy ## Footnote The SPORT trial was used to look at outcomes after various spine management strategies. For lumbar disc herniations, there was no difference between conservative and surgical management out to 4 years of follow-up on intention-to-treat analysis, however there was a 22% cross-over between groups, a common criticism of this study. When the subset as-treated analysis was performed, there was a significant improvement in all outcomes measured in the surgical group compared to conservative management with the exception of return to work. Further Reading: Weinstein et al. Surgical versus non-operative treatment for lumbar disc hernia- tion. Spine, 2008.

Answer 248

A. 25% **B. 50%** C. 75% D. 100% ## Footnote Many surgeons feel that 50% of the facet joint should remain intact during a simple decompression to preserve stability at that level. Further resection may cause iatrogenic instability. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 521.

Answer 249

A. 10% B. 35% C. 67% **D. 90%** ## Footnote Patients with achondroplasia are at risk for several conditions affecting the spine including foramen magnum stenosis, spinal stenosis and thoracolumbar kyphosis. Spinal stenosis can be observed in up to 90% of patients with achondroplasia. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 542.

Answer 250

**A. Multiple non-contiguous stenotic regions** B. < 6 months life expectancy C. Total paraplegia for 24 hours D. Age > 65 ## Footnote The Patchell study demonstrated that in patients with metastatic epidural spinal cord compression, wide decompression and reconstruction if appropriate can keep patients ambulating and extend life expectancy with several caveats. The patient’s paraplegia must be < 48 hours, there cannot be multiple non-contiguous stenotic regions and the life expectancy should be 3 months or greater. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 600.

Answer 251

A. Yes ## Footnote The Patchell study demonstrated that in patients with metastatic epidural spinal cord compression, wide decompression and reconstruction if appropriate can keep patients ambulating and extend life expectancy with several caveats. The patient’s paraplegia must be < 48 hours, there cannot be multiple non-contiguous stenotic regions and the life expectancy should be 3 months or greater. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 600.

Answer 252

A. -5-0 cm **B. 0-5 cm** C. 6-10 cm D. 11-15 cm ## Footnote The sagittal vertical axis is a measurement taken from a plum line dropped midway through the C7 vertebral body. A measurement is taken from the posterior superior corner of the sacrum to the plumb line to determine the distance. Normal is 0-5 cm. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 546.

Answer 253

A. Sagittal vertical axis B. Pelvic tilt **C. Pelvic incidence** D. Sacral slope ## Footnote The pelvic parameters are made up of the pelvic tilt, the pelvic incidence and the sacral slope. Of these, the pelvic incidence (measured as the angle from a line perpendicular to the sacral surface and a line drawn from the midpoint of the sacral surface to the midpoint of the femoral head) cannot be changed. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 546.

Answer 254

A. 1 degree or less **B. 10 degrees or less** C. 20 degrees or less D. 30 degrees or less E. 40 degrees or less ## Footnote It is becoming clear that pelvic incidence and lumbar lordosis are related measurements, and patient outcomes are improved when the difference between these two measurements are 10 degrees or less. If there is a large mismatch between the PI and LL, further evaluation should occur because a larger deformity may be present. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 548.

Answer 255

A. Pelvic retroversion B. Knee flexion **C. Pelvic incidence reduction** D. Cervical extension ## Footnote When patients have an abnormally positive sagittal vertical axis there are several mechanisms that they use to compensate in order to keep vision at the horizontal level. They utilize pelvic retroversion, knee flexion and cervical extension to maintain a view to the horizon. Pelvic incidence cannot be changed. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 548.

Answer 256

A. ~ 20 degrees B. ~ 40 degrees **C. ~ 60 degrees** D. ~ 80 degrees ## Footnote Lumbar lordosis is measured by the Cobb angle between the superior endplate of L1 and the sacral surface. The mean value for adults is 62 degrees +/− 11 degrees. It is important to restore lumbar lordosis if possible, as well as match the PI–LL to within 10 degrees or less. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 548.

Answer 257

A. 50%-50% **B. 35%-65%** C. 65%-35% D. 80%-20% ## Footnote In the cervical spine, the anterior vertebral body does not bear the axial weight in the same distribution as the lumbar spine. In the cervical spine, approximately 35% of the axial load is borne by the anterior column and 65% is borne by the posterior column.

Answer 258

A. Right ## Footnote For coronal plane deformities, the term dextroscoliosis refers to right sided diversion, where levoscoliosis depicts a leftward deviation. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015. Page 558.

Answer 259

A. Sacral slope **B. Pelvic tilt** C. Pelvic incidence D. Sagittal vertical axis ## Footnote This measurement describes the pelvic tilt. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 558.

Answer 260

**A. PI = PT + SS** B. PI = PT - SS C. PT = SS + PI D. SS = PI + PT E. Sagittal vertical axis ## Footnote Pelvic incidence can be determined using the sacral slope and pelvic tilt. They are related in the fashion PI = PT + SS. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 558.

Answer 261

A. Lumbar kyphosis B. Coronal scoliosis **C. Flat-back syndrome** D. Ankylosing spondylitis ## Footnote In this patient, there is a large mismatch in the PI/LL. Further, lumbar lordosis of only 21 degrees is concerning for flat-back syndrome. This patient very likely has a positive SVA and is at risk for poor outcome without some correction of the abnormal parameters. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 559.

Answer 262

A. < 50 degrees B. < 40 degrees C. < 30 degrees **D. < 20 degrees** ## Footnote Ideally patients should be corrected such that their PI/LL mismatch is within 10 degrees, their pelvic tilt is < 22 degrees and their SVA is < 5 cm. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 560.

Answer 263

A. 6% B. 15% **C. 29%** D. 44% E. 56% ## Footnote Patients aged 65 to 85 years who undergo scoli- osis correction procedures have a ~ 30% rate of major medical morbidity in the perioperative setting. Further Reading: Smith et al. Neurological symptoms and deficits in adults with scoliosis. JNS:Spine 2008.

Answer 264

A. 18 to 24 years B. 25 to 44 years C. 45 to 64 years **D. 65 to 85 years** ## Footnote Patients aged 65 to 85 years who undergo scoliosis correction procedures have the highest rate of improvement in disability and leg pain postoperatively. Further Reading: Smith et al. Neurological symptoms and deficits in adults with scoliosis. JNS:Spine, 2008.

Answer 265

A. < 2 years B. < 1 year C. < 6 months **D. < 3 months** ## Footnote There are a wide range of studies that report incidence of proximal junctional kyphosis after spine fusion surgery. There seems to be a consensus that a large number of these cases (~ 60%) develop within the first 3 months after surgery. Further Reading: Harbaugh et al. Neurosurgery Knowledge Update. 2015, page 565.

Answer 266

A. Instrumentation failure **B. Proximal junctional kyphosis** C. Inadequate correction D. Infection ## Footnote This image demonstrates a proximal junctional kyphosis, which can occur after large scoliosis fusion procedures. Care should be taken when exposing the top level of the construct to avoid excessive muscle damage or damage to the posterior ligamentous complex/facet joints above the upper instrumented vertebrae to decrease the chances for development of PJK. Further Reading: Vialle, Lenke, Cheung. AOSpine Masters Series, Volume 4: Adult Spinal Deformities. 2015, page 107.

Answer 267

A. > 10 degrees B. > 20 degrees **C. > 30 degrees** D. > 40 degrees ## Footnote A Cobb angle of > 30 degrees has been demonstrated to be an independent predictor of deformity progression in patients with scoliosis. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1111.

Answer 268

B. Nonflexible ## Footnote There are two types of curves, structural and nonstructural. Structural cures are not flexible, and this is demonstrated by the fact that they do not correct during side bending. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1112.

Answer 269

A. 10 cm or less **B. 4 cm or less** C. 2 cm or less D. 7 cm or less ## Footnote Coronal balance is measured using a C7 plumb line compared to the central sacral vertical line on AP radiograph. Normal is an offset of 4 cm or less. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1115.

Answer 270

**A. 5 to 10 degrees** B. 11 to 15 degrees C. 16 to 20 degrees D. 21 to 25 degrees ## Footnote A Smith Peterson osteotomy involves removing the facets, some lamina and the ligamentum flavum at a particular level and compressing this space to achieve lordosis. On average, 5 to 10 degrees of lordosis can be achieved with this technique per level. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1117.

Answer 271

A. 5 to 10 degrees B. 11 to 20 degrees **C. 21 to 30 degrees** D. 31 to 40 degrees ## Footnote A pedicle subtraction osteotomy involves removing a triangle of bone including the facet joint, some lamina and a portion of the pedicle bilaterally with the hinge point at the ALL and then compressing this space posteriorly. Doing this procedure can lead to ~ 30 degrees of correction for each level. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1117.

Answer 272

A. L2-3 B. L3-4 C. L4-5 **D. L5-S1** ## Footnote An ALIF is a direct anterior approach to the lumbar spine for interbody fusion. It is best uti- lized for fusion of the L5-S1 space given that the great vessels have split and do not need to be mobilized. Further, significant correction of lordosis can be achieved and this correction is magnified by performing this procedure at the lowest level in the spine. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1118.

Answer 273

A. Hip flexion **B. Knee extension** C. Knee flexion D. Ankle dorsiflexion ## Footnote The DLIF procedure involves either splitting the psoas muscle or going just anterior to the psoas for exposure. This puts the femoral nerve at risk for traction or direct injury during surgery, thus knee extension weakness can be seen postoperatively. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1116.

Answer 274

A. Durotomy B**. Massive blood loss** C. Infection D. Iatrogenic spine fracture ## Footnote Performing a PSO can be difficult and may lead to very significant blood loss, up to 3 L reported in one series. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1118.

Answer 275

A. Facets B. Posterior longitudinal ligament C. Mid-vertebral body **D. Anterior longitudinal ligament** ## Footnote The fulcrum at the operative level after per- forming a PSO is the anterior longitudinal ligament. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1118.

Answer 276

A. 1 cm B. 2 cm **C. 3 cm** D. 4 cm ## Footnote After cutting the ALL, approximately 3 cm of SVA correction can be achieved at each level. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1117.

Answer 277

**A. Epidural hematoma** B. Deep venous thrombosis C. Spinal cord injury D. Proximal junctional kyphosis ## Footnote This patient is likely experiencing a postoperative spinal epidural hematoma and should be evaluated immediately. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1131.

Answer 278

A. Bedside reopening **B. Spinal imaging** C. Observation D. Administration of PCCs E. EMG ## Footnote This patient is likely experiencing a postoperative spinal epidural hematoma and should be evaluated immediately. It would be wise to proceed with spinal imaging to determine the extent of the hematoma prior to returning to the OR to avoid the need to perform exploratory laminectomies to find the clot. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1131.

Answer 279

A. 3% **B. 9%** C. 15% D. 21% E. 25% ## Footnote In SCI patients who develop DVTs, mortality has been shown to be 9% in one series. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 952.

Answer 280

**A. < 1%** B. 5% C. 10% D. 15% ## Footnote A DVT that is limited to the calf only has a minute risk of embolism that is less than 1%. DVTs that extend into the more proximal venous system are higher risk. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 167.

Answer 281

**A. Pneumatic compression boots/none** B. SQ heparin 5,000 BID C. 1,000 u heparin/hour infusion D. Initiate warfarin ## Footnote This patient falls under the low risk category (< 40, procedure < 30 minutes, mobile), and therefore no pharmacologic prophylaxis is required. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 169.

Answer 282

A. Pneumatic compression boots/none **B. SQ heparin 5,000 BID** C. 1,000 u heparin/hour infusion D. Initiate warfarin ## Footnote This patient falls under the medium risk category (> 40, procedure > 30 minutes, decreased mobility), and therefore pharmacologic prophylaxis either with SQ heparin BID/TID or LMWH is indicated when deemed safe from a postoperative perspective Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 169.

Answer 283

A. < 10% **B. 10 to 40%** C. 41 to 80% D. 81 to 100% ## Footnote This patient falls under the medium risk category (> 40, procedure > 30 minutes, decreased mobility), and therefore pharmacologic prophylaxis either with SQ heparin BID/TID or LMWH is indicated when deemed safe from a postoperative perspective. Overall risk in this group is approxi- mately 10 to 40%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 169.

Answer 284

A. < 10% B. 10 to 40% **C. 41 to 80%** D. 81 to 100% ## Footnote This patient falls under the high risk category (> 40, procedure > 30 minutes, metastatic disease or high grade glial neoplasm), and therefore pharmacologic prophylaxis either with SQ heparin BID/ TID or LMWH is indicated when deemed safe from a postoperative perspective. Overall risk in this group is approximately 41 to 80%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 169.

Answer 285

A. D-dimer B. DVT ultrasound of the lower extremity **C. Contrast enhanced CT scan** D. Coagulation parameters ## Footnote The contrast enhanced CT scan of the lungs under the PE protocol is the study of choice if your clinical suspicion is high enough for PE. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 170.

Answer 286

A. SQ heparin 5,000 u TID **B. IV heparin 5,000 u followed by 1,000 u/hr infusion** C. Fresh frozen plasma D. Warfarin 5 mg daily ## Footnote If the patient can be anticoagulated, IV heparin 5,000 u should be administered followed by hourly infusions of 1,000 u of heparin with monitoring and further titration based on APTT. In postoperative neurosurgical patients administration of heparin should be monitored closely and with any neurologic change a STAT head CT should be obtained. Intracranial hemorrhage can occur during heparin administration. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 170.

Answer 287

A. < 100 mL/day **B. < 400 mL/day** C. < 800 mL/day D. < 1,200 mL/day ## Footnote It is important to monitor postoperative I/Os especially for elderly patients or patients who have had a large procedure. Oliguria is characterized by < 400 mL of urine production/day Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 288

**A. Prerenal** B. Intrinsic renal C. Postrenal D. Ureteral ## Footnote NSAIDS, along with ACE inhibitors and se- vere hypovolemia cause prerenal oliguric renal failure. NSAIDS cause this by promoting renal vasoconstriction. Further Reading: Marino. The ICU Book, page 620. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 289

A. Prerenal **B. Intrinsic renal** C. Postrenal D. Uretera ## Footnote ATN is an intrinsic renal failure as the epithelial cells slough off and form an obstruction within the renal tubules. This is often caused by ischemia. Further Reading: Marino. The ICU Book, page 621. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 290

A. Prerenal ## Footnote This patient likely has pre-renal oliguric renal failure given the low urinary sodium. When perfusion is limited, urinary sodium excretion decreases, leading to a low urinary sodium. Urinary sodium < 20 mEq/L helps to establish the diagnosis. Further Reading: Marino. The ICU Book, page 623. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 291

B. Intrinsic renal ## Footnote With intrinsic renal disease, urinary sodium excretion increases (compared to pre-renal where it decreases) and a urine sodium of > 40 mEq/L can help lead to the diagnosis. Urinary sodium cannot distinguish the patient that has intrinsic renal failure with a superimposed pre-renal syndrome however, so it is not absolute. Further Reading: Marino, The ICU Book, page 623. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 292

A. Prerenal ## Footnote In patients with renal failure, FEna can be useful to determine etiology. A FEna of < 1% suggests pre-renal oliguria. Further Reading: Marino. The ICU Book, page 623. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, page 510.

Answer 293

**A. Polymorphous ventricular tachycardia (torsades)** B. Ventricular fibrillation C. Bradycardia D. Wolf-Parkinson-White syndrome ## Footnote Patients with severe magnesium deficiency can develop severe cardiac arrhythmias, including torsade de pointes (polymorphous ventricular tachycardia). Further Reading: Marino. The ICU Book, page 665. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, critical care section.

Answer 294

A. Total calcium **B. Ionized calcium** ## Footnote Calcium exists in the plasma in several forms, including protein bound (~ 50%) and ionized forms. The protein bound calcium is mostly bound to levels of albumin, which can fluctuate. The total calcium lab value fluctuates with this change, but the ionized calcium level remains the same, and it is the most important physiologic calcium level. Further Reading: Marino. The ICU Book, page 674.

Answer 295

A. Hypercalcemia **B. Hypocalcemia** ## Footnote Hypocalcemia can manifest neurologically with muscular and cardiac excitability as well as hyperreflexia. Tetany is seen in severe cases of hypocalcemia. Further Reading: Marino. The ICU Book, page 677.

Answer 296

A. Sodium B. Potassium C. Calcium **D. Phosphorous** ## Footnote Refeeding syndrome occurs in patients with chronic malnutrition and alcoholics. In these patients, the body already has severely low levels of phosphorous, and when a glucose load is given, phosphorous follows glucose into the cell and serum levels of phosphorous can drop to dangerous levels. Further Reading: Marino. The ICU Book, page 682.

Answer 297

A. 1 in 20,000 B. 1 in 200,000 **C. 1 in 2,000,000** D. 1 in 20,000,000 ## Footnote The current reported risk of HIV seroconversion after receiving blood contaminated with HIV is roughly 1 in 2,000,000. Further Reading: http://www.redcrossblood.org/ learn-about-blood/blood-transfusions/risks- complications

Answer 298

A. 1 in 30,000 **B. 1 in 300,000** C. 1 in 3,000,000 D. 1 in 30,000,000 ## Footnote The current reported risk of Hepatitis B infection after receiving blood contaminated with the virus is roughly 1 in 300,000. Further Reading: http://www.redcrossblood.org/ learn-about-blood/blood-transfusions/risks- complications

Answer 299

A. Hemorrhage **B. Thrombosis** C. Hypotension D. Hypertension ## Footnote The major risk of heparin-induced thrombocytopenia is thrombosis, not hemorrhage. HIT occurs when heparin combines with platelet factor 4 and forms an antigenic complex leading to production of IgG. The IgG then binds to platelets and promotes clumping of platelets which can ultimately lead to thrombosis of vessels. Further Reading: Marino. The ICU Book, page 711.

Answer 300

A. Platelet transfusion B. Warfarin administration **C. Stop all heparin** D. Fluid resuscitation ## Footnote The initial management of HIT is to of course stop all forms of heparin administration, including heparinized catheters and heparin flushes. Further Reading: Marino. The ICU Book, page 711.

Answer 301

**A. Beta agonists** B. Hyperglycemia C. Respiratory acidosis D. Hyperthermia ## Footnote Beta agonists (albuterol for example) can lead to transcellular shift of potassium and cause a serum hypokalemia. Other factors that can cause this include insulin administration, alkalosis and hypothermia. Further Reading: Marino. The ICU Book, page 649.

Answer 302

A. Beta agonists B. Insulin administration **C. Respiratory acidosis** D. Hypothermia ## Footnote Potassium acts as a buffering agent for hydro- gen ions at the cellular level. When a patient is acidotic, hydrogen ions are shuttle into the cell in exchange for potassium which is shifted extracellularly. This can help decrease the acidosis, but a resultant hyperkalemia can occur. Further Reading: Marino. The ICU Book, page 653.

Answer 303

A. 5.5 mEq/L **B. 6.0 mEq/L** C. 6.5 mEq/L D. 7.0 mEq/L E. 8.0 mEq/L ## Footnote Hyperkalemia can lead to cardiac arrhythmias, and changes on a patient’s ECG can be seen with levels of 6.0 mEq/L. Further Reading: Marino. The ICU Book, page 655.

Answer 304

A. Increased PR interval **B. Peaked T waves** C. Widening of the QRS complex D. Asystole ## Footnote Hyperkalemia can lead to cardiac arrhythmias, and changes on a patient’s ECG can be seen with levels of 6.0 mEq/L. Often the first sign is a tall, peaked T wave. Further Reading: Marino. The ICU Book, page 655.

Answer 305

A. Call a code **B. Administer calcium gluconate** C. Obtain echocardiogram D. Recheck the electrolyte panel ## Footnote Hyperkalemia can lead to cardiac arrhythmias, and changes on a patient’s ECG can be seen with levels of 6.0 mEq/L. Often the first sign is a tall, peaked T wave. Advanced ECG changes include loss of the P wave and widening of the QRS complex. In patients with advanced ECG changes and hyperkalemia, initial management should include administration of calcium gluconate, as calcium antagonizes the membrane effects of potassium. Further Reading: Marino. The ICU Book, page 655.

Answer 306

A. Call a code B. Administer calcium gluconate C. Obtain echocardiogram **D. Recheck the electrolyte panel** ## Footnote Hyperkalemia can lead to cardiac arrhythmias, and changes on a patient’s ECG can be seen with levels of 6.0 mEq/L. Often the first sign is a tall, peaked T wave. Advanced ECG changes include loss of the P wave and widening of the QRS complex. In patients with advanced ECG changes and hyperkalemia, initial management should include administration of calcium gluconate, as calcium antagonizes the membrane effects of potassium. In clinically normal patients with no ECG changes, the potassium level should be repeated due to the high rate of pseudohyperkalemia (20%) caused by traumatic hemolysis. Further Reading: Marino. The ICU Book, page 652.

Answer 307

A. T **B. L** C. D D. N ## Footnote A coronal curve > 30 degrees is considered a major curve and a patient with a lumbar curve of > 30 degrees and a thoracic curve < 30 degrees would be considered an L according to the SRSSchwab classification. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1112.

Answer 308

A. T B. L **C. D** D. N ## Footnote A coronal curve > 30 degrees is considered a major curve and a patient with a lumbar curve of > 30 degrees and a thoracic curve > 30 degrees would be considered a D according to the SRSSchwab classification. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1112.

Answer 309

A. 0 to 20% B. 21 to 40% **C. 41 to 60%** D. 61 to 80% ## Footnote The ODI has been used to characterize patient’s pain, and a score of 41 to 60% would indicate that the patient’s pain is interfering with multiple activities, including activities of daily living. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1026.

Answer 310

**A. 0 to 20%** B. 21 to 40% C. 41 to 60% D. 61 to 80% ## Footnote The ODI has been used to characterize patient’s pain, and a score of 0-20% would indicate that the patient’s pain is managed with repositioning and mild activity modification. Further Reading: Greenberg. Handbook of Neuro- surgery. 8th edition. 2016, page 1026.

Answer 311

A. 1 **B. 2** C. 3 D. 4 ## Footnote The Meyerding classification is used to quantify the grade of spondylolisthesis. Grade 1 is 0 to 25%, grade 2 is 25 to 50%, etc. This case is a grade 2 spondylolisthesis. Further Reading: Abdulhak, Marzouk. Challenging Cases in Spine Surgery, 2006, page 100.

Answer 312

**A. A** B. B C. C D. D ## Footnote Given that this patient does not have motor or sensory function below the level of injury, they would classify as an ASIA A injury. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1607.

Answer 313

A. A **B. B** C. C D. D ## Footnote Given that this patient has no motor function below the injury but has preserved sensation they would be classified as an ASIA B injury. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1607.

Answer 314

A. 1 B. 2 **C. 3** D. 4 ## Footnote According to the SLIC system, this patient’s fracture morphology would classify as distraction (perched facets) and receive a score of 3. This score is added to PLC integrity and neurology to determine the final score. A score of 5 suggests operative intervention is likely required. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1607.

Answer 315

**A. 1** B. 2 C. 3 D. 4 ## Footnote According to the SLIC system, this patient’s fracture morphology would classify as distraction (perched facets) and receive a score of 3. The interspinous widening suggests possible PLC injury and 1 point would be scored given the indeterminate PLC status. A score of 5 suggests operative intervention is likely required. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1607.

Answer 316

A. 1 B. 2 **C. 3** D. 4 ## Footnote According to the SLIC system, this patient’s fracture morphology would classify as distraction (perched facets) and receive a score of 3. The interspinous widening suggests possible PLC injury and 1 point would be scored given the indeterminate PLC status. Given the incomplete status of the neurologic injury, a score of 3 points is given for neurology. A score of 5 suggests operative intervention is likely required. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 1607.

Answer 317

A. 2 **B. 3** C. 4 D. 5 ## Footnote The MRC grading system is widely used to grade muscle strength. A strength grade of 3 is full range of motion strength against gravity. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 505.

Answer 318

A. Myoclonus **B. Fibrillations** C. Fasciculations D. Tetany ## Footnote Fibrillation potentials occur with muscle denervation and can only be observed on EMG. Fasciculations occur with the death of anterior horn cells and are observable at rest. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 506.

Answer 319

A. 6 months B. 12 months **C. 24 months** D. 36 months ## Footnote Generally, after a muscle has atrophied after a period of denervation lasting 24 months there is little to no hope of recovery of function even with nerve grafting. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 510.

Answer 320

A. 6 to 8 days **B. 6 to 8 weeks** C. 6 to 8 months D. 6 to 8 years ## Footnote While some neurapraxic peripheral nerve injuries will recover in hours, in many cases it can take 6 to 8 weeks for full recovery. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 321

A. Fasciculations B. Preserved SNAP **C. Wallerian degeneration** D. Presence of voluntary potentials ## Footnote Based on the Seddon classification, there are three types of peripheral nerve injuries, neurapraxia (conduction block but preservation of the axon, spontaneous recovery occurs), axonotmesis (disruption of the axon but preservation of surrounding structures) and neurotmesis (complete disruption of the nerve structure). In axonotmesis and neurotmesis, Wallerian degeneration occurs distal to the injury, but it does not in neurapraxia. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 322

A. Grade I B. Grade II **C. Grade III** D. Grade IV ## Footnote The Sunderland classification further subdivides the neurotmesis group of the Seddon classification. Sunderland grade I is the same as neurapraxia, Sunderland grade II is the same as axonotmesis (disruption of axon), grade III involves disruption of the endoneurium with preservation of the perineurium and epinerium, grade IV involves disruption of the perineurium and grade V involves disruption of all supporting fibers. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 323

A. Grade I B. Grade II C. Grade III **D. Grade IV** ## Footnote The Sunderland classification further subdivides the neurotmesis group of the Seddon classification. Sunderland grade I is the same as neurapraxia, Sunderland grade II is the same as axonotmesis (disruption of axon), grade III involves disruption of the endoneurium with preservation of the perineurium and epinerium, grade IV involves disruption of the perineurium and grade V involves disruption of all supporting fibers. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 324

A. Grade II B. Grade III C. Grade IV **D. Grade V** ## Footnote The Sunderland classification further subdivides the neurotmesis group of the Seddon classification. Sunderland grade I is the same as neurapraxia, Sunderland grade II is the same as axonotmesis (disruption of axon), grade III involves disruption of the endoneurium with preservation of the perineurium and epinerium, grade IV involves disruption of the perineurium and grade V involves disruption of all supporting fibers. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 325

A. Fibrillation potentials B. Muscle atrophy **C. Immobile Tinel’s sign** D. MRC grade IV strength ## Footnote In patients with grade III injuries, there will likely be a Tinel’s sign over the area of injury that slowly progresses distally with nerve regeneration. This generally does not occur in grade IV injuries as a neuroma in continuity develops. At one month follow-up, a grade IV lesion will likely have a Tinel’s sign at the same location, whereas a grade III lesion likely will have demonstrated some distal transition Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 326

**A. 1 mm/day** B. 1 cm/day C. 1 mm/week D. 1 cm/month ## Footnote Nerves regenerate at roughly 1 mm/day. In grade II lesions, the Tinel’s sign should progress distally at a rate of approximately 1 mm/day. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 551.

Answer 327

A. < 6 hours B. < 24 hours **C. < 72 hours** D. < 1 week ## Footnote In clean transection injuries, direct nerve repair should be undertaken within 72 hours for the best outcome. Further Reading: http://digitalcommons.unl.edu/ cgi/viewcontent.cgi?article=1002&context=usuhs

Answer 328

A. Immediate debridement and direct repair **B. Debridement and tagging of the nerve endings** C. Debridement and closure of the wound D. Debridement and nerve graft ## Footnote In cases of contaminated nerve injury, wound debridement should occur and transected edges of nerve should be tagged and sutured to local structures to prevent nerve ending retraction. Antibiotics should be administered and nerve repair can occur when any infection has been fully treated. A contaminated nerve injury should not be immediately repaired as any subsequent infection may inhibit nerve regeneration. Further Reading: http://digitalcommons.unl.edu/ cgi/viewcontent.cgi?article=1002&context=usuhs

Answer 329

**A. Direct nerve repair** B. Nerve graft repair C. Nerve transfer D. Tendon transfer ## Footnote In clean transection injuries, direct nerve repair should be undertaken within 72 hours for the best outcome. Direct neurorrhaphy will likely provide the best functional outcome rather than nerve grafting or other techniques. This is assuming a tension free repair is possible. Further Reading: http://digitalcommons.unl.edu/ cgi/viewcontent.cgi?article=1002&context=usuhs

Answer 330

A. 24 hours B. 1 week **C. 3 weeks** D. 3 months ## Footnote In suspected cases of Sunderland grade II+ lesions, initial EMG should be performed approximately 3 weeks after the injury to allow Wallerian degeneration to occur. Even in an axonotmesis or neurotmesis level injury, the distal stump can continue to conduct for 1 week after the injury. This topic is somewhat controversial however, as some believe that immediate EMG can be beneficial for injury localization. Further Reading: http://digitalcommons.unl.edu/ cgi/viewcontent.cgi?article=1002&context=usuhs

Answer 331

A. Preoperative MRC grade **B. Distance from injury to end muscle** C. Age D. Sunderland grade ## Footnote In most cases, surgical repair utilizing end to end direct repair or grafting occurs sometime between 3 and 6 months after injury. Timing is based on several factors, but most importantly, the distance of nerve regeneration between the area of injury and the target muscle should be considered. Longer distances for regeneration should be operated earlier in an attempt to beat the “24-month rule” where irrecoverable atrophy of the muscle has occurred. Some surgeons consider 18 months the point at which irrecoverable atrophy has occurred. Further Reading: http://digitalcommons.unl.edu/ cgi/viewcontent.cgi?article=1002&context=usuhs

Answer 332

A. Deltoid B. Biceps C. Triceps **D. Abductor pollicis brevis** ## Footnote At this time, recovery of hand function lost after brachial plexus injury is very unlikely to occur even with prompt surgical repair of the affected nerves. The distance required for nerve regeneration to the target muscle is too long and irreversible atrophy often occurs before regeneration can reach the hand. Further Reading: Campbell. Evaluation and Management of Peripheral Nerve Injuries, 2008.

Answer 333

A. Horner’s syndrome B. Winged scapula C. Pseudomeningocele on MRI **D. Disrupted SNAP** ## Footnote It is important to determine whether a brachial plexus injury is pre-ganglionic or post-ganglionic. Preganglionic injuries are often caused by nerve root avulsion and no neurolysis or nerve repair of the brachial plexus will fix this type of injury. Patients with preganglionic injuries will often demonstrate a winged scapula (long thoracic loss), pseudomeningocele on MRI, a Horner’s syndrome (lower trunk injuries) and intact SNAP even in anesthetic regions. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 552.

Answer 334

**A. Continue to observe** B. Perform plexus exploration ## Footnote Pure upper trunk obstetrical brachial plexus palsies should be observed in children as they have a 90% recovery rate. Surgery should be reserved for children who do not exhibit adequate recovery. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 553.

Answer 335

A. Thoracodorsal nerve **B. Long thoracic nerve** C. Medial antebrachial cutaneous nerve D. Suprascapular nerve ## Footnote The long thoracic nerve innervates the serratus anterior and can cause winging of the scapula. It branches at the root level of the brachial plexus and can be helpful in differentiating preganglionic from postganglionic injuries. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition. 2016, page 552.

Answer 336

A. 3 cm B. 5 cm C. 7 cm **D. 9 cm** ## Footnote The upper trunk has a larger diameter than the sural nerve, and therefore you should plan to harvest at least 3x the required distance of sural nerve in order to create a cable graft that will better approximate the diameter of the upper trunk. Further Reading: Campbell. Evaluation and Management of Peripheral Nerve Injuries, 2008.

Answer 337

A. Positioning palsy **B. Idiopathic brachial plexitis** C. Nerve root stretch D. Epidural hematoma ## Footnote The onset of intense shoulder pain without weakness initially should concern you for the development of idiopathic brachial plexitis, or “Parsonage-Turner syndrome.” Often this presents with severe shoulder pain followed by development of weakness in one or more muscle groups. There are several potential etiologies including postoperative inflammatory reactions as well as viral disease, but nothing proven. Recovery is thought to be roughly 89% at 3 years. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 544.

Answer 338

B. No ## Footnote “Parsonage-Turner syThe onset of intense shoulder pain without weakness initially should concern you for the development of idiopathic brachial plexitis, or “Parsonage-Turner syndrome.” Often this presents with severe shoulder pain followed by development of weakness in one or more muscle groups. There are several potential etiologies including postoperative inflammatory reactions as well as viral disease, but nothing proven. Recovery is thought to be roughly 89% at 3 years. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, page 544.ndrome.” Often this presents with severe shoulder pain followed by development of weakness in one or more muscle groups. There are several potential etiologies including postoperative inflammatory reactions as well as viral disease, but nothing proven. Recovery is thought to be roughly 89% at 3 years. While many physicians give steroids, there are no studies demonstrating any benefit of steroids in this circumstance. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, non-entrapment peripheral neuropathies section.

Answer 339

**A. Median** B. Ulnar C. Radial D. Musculocutaneous ## Footnote The ligament of struthers is present in ~ 3% of patients and connects a supracondylar process (5 cm proximal to the medial epicondyle) to the medial epicondyle. The median nerve and brachial artery pass under the ligament which can cause median nerve compression. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 340

A. Benedictine hand B. Froment’s sign **C. Abnormal pinch sign** D. Positive Phalen test ## Footnote The anterior interosseus nerve is a pure motor branch of the median nerve that can be compressed by a vascular or soft tissue band as it branches. On exam there is an abnormal pinch sign (flat pinch) due to weakness of the flexor digitorum profundus and flexor pollicis longus Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropa- thies section.

Answer 341

A. Give oral cortisone B. Right carpal tunnel decompression **C. EMG** D. Steroid injection ## Footnote This patient has symptoms consistent with carpal tunnel syndrome. Physical exam findings can be somewhat unreliable, and EMG examination is the most sensitive test to localize the compression to the carpal tunnel. If possible, EMG should be performed to confirm prior to surgical decompression. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 342

A. 35% B. 55% **C. 75%** D. 95% ## Footnote Carpal tunnel release has a reported satisfactory success rate of 75 to 90%. Clinical improvement generally peaks at 6 months, but sensory paresthesias may take even longer to respond. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 343

A. Hypothenar atrophy B. Sensory loss on the palmar aspect of the hand **C. Sensory loss on the dorsal aspect of the hand** D. Interossei weakness ## Footnote The dorsal cutaneous branch of the ulnar nerve branches from the ulnar nerve 5-8 cm proximal to Guyon’s canal, so if there is sensory numbness on the dorsum of the hand, the compression must be proximal to Guyon’s canal. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 344

A. Herniated lumbar disk B. Discogenic back pain **C. Meralgia paresthetica** D. Muscle spasm ## Footnote This condition is most consistent with meralgia paresthetica, or compression of the lateral femoral cutaneous nerve. It often occurs in obese patients or people who wear tight fitting clothing, including belts. It has recently been described in runners. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 345

A. Surgical decompression B. Steroid injection **C. Weight loss** D. Observation ## Footnote This condition is most consistent with meralgia paresthetica, or compression of the lateral femoral cutaneous nerve. It often occurs in obese patients or people who wear tight fitting clothing, including belts. It has recently been described in runners. In overweight patients, weight loss should first be attempted as this can reverse the condition. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 346

A. 30% B. 50% C. 70% **D. 90%** ## Footnote Meralgia paresthetica is caused by compression of the lateral femoral cutaneous nerve. It often occurs in obese patients or people who wear tight fitting clothing, including belts. It has recently been described in runners. In overweight patients, weight loss should first be attempted as this can reverse the condition. Approximately 90% of these cases will resolve with conservative management and do not require surgery. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 347

A. Finger extensor weakness **B. Wrist drop** C. Flexor pollicis longus weakness D. Coracobrachialis weakness ## Footnote The radial nerve branches into the posterior inerosseous nerve and the superficial radial sensory nerve. The PIN can be compressed leading to finger extensor weakness, but since the branches to the wrist extensors have already branched prior to the PIN, wrist drop is not present in PIN palsy. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 348

A. Foot eversion **B. Foot inversion** C. Ankle dorsiflexion D. Ankle plantarflexion ## Footnote Differentiating an L5 radiculopathy from a CPN palsy can be difficult, and hints are given based on the presentation. EMG can be helpful. Foot inversion will be weak in cases of L5 radiculopathy but preserved in CPN palsy. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 349

**A. Deep** B. Superficial C. Articular D. None of the above ## Footnote The deep branch of the CPN innervates the anerior tibilais while the superficial branch innervates the peroneus longus and brevis. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 350

A. True ## Footnote In tarsal tunnel syndrome there is often pain on the bottom of the foot as well as weakness of toe flexion/intrinsic musculature. There is often sparing of sensation of the heel given that the sensory branches to the heel have already left the tibial nerve before it passes through the retinaculum. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 351

**A. Suprascapular nerve** B. Dorsal scapular nerve C. Axillary nerve D. Long thoracic nerve ## Footnote The suprascapular nerve innervates the supraspinatous (shoulder abduction) and infraspinatous (external rotation). Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 352

B. False ## Footnote Type II compression of the ulnar nerve in Guyon’s canal is purely compression of the deep branch which is a pure motor branch with no sensory innervation. Types I and III both have involvement of varying degrees of ulnar sensation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 353

**A. Wrist ganglion** B. Aneurysm C. Transverse carpal ligament D. Bone spur ## Footnote A wrist ganglion is the most common cause of compression within Guyon’s canal. Further Reading: Greenberg. Handbook of neurosurgery. 8th edition, entrapment neuropathies section.

Answer 354

A. Martin-Gruber hand B. Riches-Cannieu hand **C. Gilliatt-Sumner hand** D. Froment’s sign ## Footnote A cervical rib causing neurologic compression can lead to thoracic outlet syndrome which has a characteristic physical exam finding, the Gilliatt-Sumner hand, with weakness and atrophy of both the thenar and hypothenar areas as well as interossei weakness. Atrophy of both of these re- gions should make you think of a plexus etiology or aberrant hand innervation. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, non-entrapment neuropathies section.

Answer 355

A. Dorsal scapular nerve B. Long thoracic nerve **C. Phrenic nerve** D. Suprascapular nerve ## Footnote The phrenic nerve runs on the anterior scalene muscle and can be damaged during brachial plexus exploration. Care should be taken to protect the phrenic nerve during dissection. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, non-entrapment neuropathies section.

Answer 356

A. > 1.4 msec B. > 2.3 msec C. > 3.0 msec **D. > 3.7 msec** ## Footnote EMG is a very sensitive test for CTS, and a gold standard EMG evaluation includes sensory latency across the median nerve at the wrist. Sensory latency > 3.7 msec is diagnostic of CTS. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, entrapment neuropathies section.

Answer 357

**A. Stimulated activity** B. Insertional activity C. Spontaneous activity D. Volitional activity ## Footnote There are three phases to the EMG examination, insertional activity, spontaneous activity and volitional activity. There is no stimulated activity as a part of the routine EMG examination. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, Electrodiagnostics Section.

Answer 358

A. True ## Footnote A lumbar radiculopathy caused by a HLD involves the nerve roots, and given that the DRG will not be affected (at least initially) the SNAP will be normal on EMG. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 359

B. False ## Footnote In a suspected brachial plexopathy the injury is most likely distal to the DRG and therefore the SNAP will be abnormal on EMG. Further Reading: Greenberg. Handbook of Neu- rosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 360

A. True ## Footnote In a suspected nerve root avulsion the DRG will remain intact and therefore the SNAP will be normal on EMG. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 361

A. 35% B. 55% **C. 85%** D. 100% ## Footnote EMG examinations can be highly dependent on the EMG technician, but the approximate accuracy of diagnosing the level of a lumbar radiculopathy based on EMG alone is ~ 85%. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 362

A. Insertional activity B. Spontaneous activity **C. Volitional activity** D. Stimulated activity ## Footnote MUAPs are recorded during the volitional activity portion of the EMG examination to determine if the patient is able to recruit any function with volitional activity. Stimulated activity is not a phase of the routine EMG examination. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 363

A. Insertional activity **B. Spontaneous activity** C. Volitional activity D. Stimulated activity ## Footnote Muscle fibrillations occur spontaneously and therefore are best evaluated during the spontaneous activity phase of the EMG examination. Stimulated activity is not a phase of the routine EMG examination. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 364

A. Herniated lumbar disk **B. Multilevel radiculopathy** C. Nerve root avulsion D. Neuroma formation ## Footnote The F wave on EMG is helpful in that it suggests multilevel involvement rather than an individual level. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 365

A. 24 hours **B. 7 to 10 days** C. 3 months D. 12 months

Answer 366

**A. Denervation** B. Ischemic muscle C. Guillain-Barre syndrome D. Malignant peripheral nerve sheath tumor ## Footnote Positive sharp waves are observed on the spontaneous phase of EMG and are indicative of denervated muscle. They are seen along with fibrillation potentials Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 367

A. L4 B. L5 **C. S1** D. S2 ## Footnote The H-reflex is similar to the ankle-jerk reflex, but it is the EMG version. It is only useful to evaluate the S1 nerve root. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 368

A. H-reflex B. F-wave **C. Polyphasic MUAPs** D. Sharp waves ## Footnote Polyphasic MUAPs are seen on EMG after reinnervation begins following nerve injury. They represent abnormal MUAPs and are seen for several months before they begin to fade away. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 369

A. 12 hours B. 1 week **C. 3 weeks** D. 3 months ## Footnote Often times it takes approximately 3 weeks for acute changes on EMG examination to be present in the case of radiculopathy. Further Reading: Greenberg. Handbook of Neu- rosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 370

A. 1 month B. 3 months **C. 6 months** D. 12 month ## Footnote Often times it takes approximately 6 months for chronic changes on EMG examination to be present in the case of radiculopathy. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 371

B. False ## Footnote There are no reliable muscle groups that can be utilized to determine the presence of a C4 radiculopathy on EMG. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 372

A. Patient with lumbosacral plexopathy **B. Post-laminectomy patient** C. Patient with meralgia paresthetica D. Patient with common peroneal nerve injury ## Footnote Postlaminectomy patients often do not have paraspinal muscle activity on EMG given that those muscles are often affected by the surgical exposure. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 373

A. Insertional activity B. Spontaneous activity **C. Volitional activity** D. Stimulated activity ## Footnote Interference pattern is evaluated during volitional activity. During volitional muscle contraction, the interference should block out all other activity on the EMG examination. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 374

**A. Motor unit loss** B. Nerve root avulsion C. Multiple affected nerve roots D. Abnormal S1 nerve root ## Footnote Interference pattern is evaluated during volitional activity. During volitional muscle contraction, the interference should block out all other activity on the EMG examination. When reduced interference is seen, it is likely due to loss of motor units. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 375

**A. Myotonic discharges** B. Motor unit loss C. Multiple affected nerve roots D. Abnormal S1 nerve root ## Footnote The dive bomber sound on EMG is consistent with myotonic discharges from muscle. This is seen in any condition causing myotonia. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 376

B. False ## Footnote EMG can be useful to help differentiate location or even etiology of a neuropathy, but in cases where there is a normal motor examination the EMG findings are highly likely to be normal as well. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

Answer 377

B. Specific ## Footnote For lumbar radiculopathy, EMG may have some difficulty with sensitivity in picking up the radiculopathy, however when an abnormality is present, EMG is highly specific. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, electrodiagnostics section.

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