NeuroSurgery Flashcards

Question

What is the treatment of choice for chronic, intractable brachial plexus avulsion injury? A. Cordotomy B. Dorsal root entry zone (DREZ) lesioning C. Morphine pump placement D. Midline myelotomy E. Ventroposterior lateral (VPL) thalamic deep brain stimulation

Answer 1

A. Cordotomy **B. Dorsal root entry zone (DREZ) lesioning ** C. Morphine pump placement D. Midline myelotomy E. Ventroposterior lateral (VPL) thalamic deep brain stimulation ## Footnote Dorsal root entry zone (DREZ) lesioning involves radiofrequency ablation along the dorsolateral sulcus of the spinal cord. The DREZ procedure is most effective in the treatment of brachial and lumbar plexus avulsion pain. Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region; however, it is associa ted wi th many complica tions and is usually performed only in terminally ill patients. Complications of cordotomy include hemiparesis, respiratory depreSSion ("Ondine's curse" with bilateral procedures), and dysesthesias. Midline mye!otomies can also be performed to interrupt the decussating fibers of the spinothalamic tract, and this can be quite effective in the treatment of chronic pelvic pain secondary to cancer. Intrathecal narcotic administration is typically used for the treatment of chronic pain associated with malignancy or failed low back syndrome. Deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray have been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Chronic low-threshold stimulation of the motor cortex is also utilized in the treatment of thalamic pain syndromes; it is thought to work by retrograde thalamic stimulation pathways (Kaye and Blacl<, pp. 1521- 1537; Greenberg, pp. 365-370; Youmans, pp. 3025- 3030, 3045-3048, 3068- 3070, 3101, 3125, 3128-3129; Will

Answer 2

A. 1,2, and 3 are correct **B. 1 and 3 are correct ** C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote The ambient and crural cisterns contain portions of the basal vein of Rosenthal (Youmans, pp. 36- 39).

Answer 3

A. Left lambdoid synostosis B. Right lambdoid synostosis C. Sagittal suture synostosis **D. Skull molding ** E. Right coronal suture synostosis ## Footnote Lambdoid synostosis is among the rarest forms of suture synostosis, while sagittal synostosis is the most common. After the American Academy of Pediatrics published its recommendations that all children sleep on their back, the incidence of skull molding increased. Most infants sleep on their backs and spend the rest of the day sitting in a car seat or infant seat. Children with this condition are often noted to have a flat occiput, one ear that is anterior to the other in an axial plane, and a prominent forehead and malar eminence. Many infants may also have a mild torticollis due to a shortened sternocleidomastoid muscle on one side, as well as decreased range of motion in the neck. The skull deformity usually responds very well to behavioral modification, which includes having the parents turn the infant or child from side to side during sleep and reducing the amount of time spent in a car seat. If this is unsuccessful, a molding helmet or band is often helpful. For nonresponders, a variety of occipital remolding surgical procedures are available (Committee on Education in Neurological Surgery, pp. 43, 137; Pattisapu, pp.178- 179)

Answer 4

A. Old fractures (> 6 weeks) B. Diagonal fractures through the odontoid process C. Barrel-chested patient D. Odontoid fracture that is displaced anteriorly **E. An intact transverse ligament** ## Footnote An intact transverse ligament must be confirmed preoperatively prior to placement of an odontoid screw. Old fractures in which a nonunion has already formed, diagonal fractures through the odontoid process, and comminuted odontoid fractures do not aUow for proper odontoid screw placement due to suboptimal arthrodesis rates and inadequate screw purchase and compression effects (Kaye and Blacl<, pp. 2048-2050; Youmans, pp. 4943- 4945; Benzel, pp.225- 228).

Answer 5

**A. Injury of a blood vessel originating from the A2 segment of the anterior cerebral artery ** B. Venous infarct from excessive frontal lobe retraction C. Injury to the small perforating blood vessels originating from the anterior communicating artery D. Posterior internal capsule infarction from microemboli originating from the internal carotid artery E. Mesial temporal lobe retraction ## Footnote A. The recurrent artery of Heubner usually originates from the A2 segment of the anterior cerebral artery (ACA). Injury of this vessel during surgery is generally witnessed on the first postoperative day, as evidenced by a hypodensity on CT scan. Although injury to this vessel during surgery often presents with arm wealmess greater than leg wealmess on the nondominant side and cognitive deficits from injury on the dominant Side, a percentage of patients do not have any adverse neurologic sequelae after injury of this vessel. Identifying this vessel early in the dissection may prevent later injury (Greenberg, pp. 103-104).

Answer 6

A. a-Fetoprotein, saliva **B. Transferrin, vitreous fluid of the eye ** C. ~2- Transferrin, tears D. Hypoglycorrhachia, nasal secretions E. Sodium, peritoneal fluid ## Footnote Prtransferrin is present in the CSF but absent in the tears, saliva, peritoneal fluid , nasal exudates, and serum (except for newborns or those with liver disease). The only other source is the vitreous humor of the eye. Other commonly employed tests include measuring the glucose level of the fluid (CSF glucose> 30 mg %, whereas lacrimal and mucous secretions are < 5 mg%) or placing the fluid on a piece of linen (bed sheet, pillowcase) and seeing whether a ring of blood surrounded by a larger concentric ring of clear fluid develops ("ring" or "halo" sign) (Greenberg, pp. 168- 169).

Answer 7

A. May be assoc iated with late neurologic deficits B. A dural laceration is always present C. There may be ongoing damage to underlying brain from continued herniation of brain through the defect **D. CSF diversion is often the only treatment required for this fracture pattern ** E. May be associated with leptomeningeal cyst development ## Footnote Growing skull fractures occur in children, are always associated with underlying dural lacerations, and almost always require surgical treatment. Early surgical correction of growing fractures is often necessary because these types of fractures almost never heal spontaneously and late neuro logic deterioration can occur. The pathophysiology requires a fracture with enough force to cause a tear in the dura (which is always present) and an underlying constant force such as a growing brain, leptomeningeal cyst, hydrocephalus, or porencephaly. The precise etiology of late neurologic deficits remains unclear but is believed to occur by one of two mechanisms. There may be ongoing brain damage from brain herniation and pulsations of the brain against the bone edges. Alternatively, some have proposed that there may be vascular compromise of blood vessels at the bone edges. Although some authors have recommended a CSF diversion procedure for growing skull fractures, direct repair of the fracture is the definitive treatment (Youmans, pp. 3468-3469; Will

Answer 8

A. Radiation-induced plexopathy is frequently accompanied by pain and lack of edema B. Cancerous invasion of the brachial plexus is accompanied by lymphedema, painless wealmess, and sensory loss C. Radiation-induced plexopathy is frequently reversible **D. l'vlyokymia on EMG favors radiation-induced plexopathy ** E. Prolonged I-I latency is typically seen only with brachial plexopathy secondary to radiation damage ## Footnote Myokymia (quivering of muscles) on EMG strongly favors radiation-induced changes of the brachial plexus. Lymphedema, painless paresis, and numbness suggest radiation-induced injury (irreversible), whereas pain and lack of edema suggest recurrent tumor. When ancillary studies are inconclusive, surgical exploration of the plexus may have to be considered (Merritt, p. 459)

Answer 9

A. 1,2, and3 are correct **B. 1 and 3 are correct ** C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote Current head injury research guidelines suggest that mannitol and hyperventilation may exacerbate cerebral ischemia after head injury. However, mannitol and hyperventilation are recommended for those patients with acute head injury as a temporary measure to control elevated intracranial pressure. Hyperventilation may be commenced immediately, but mannitol should be withheld until the primary survey is complete and adequate intravascular volume and urine output are realized. The mechanism of action of mannitol is still debated, but it is believed to have the follOWing beneficial effects. First, it acts to immediately expand the plasma by reducing hematocrit and blood viscosity (improved rheology), which improves CBF and O2 delivery. This reduces ICP very quicldy, which is most marked in patients with CPP < 70 mm r-rg. Second, it draws edema from the adjacent cerebral parenchyma into the intravascular compartment (osmotic effect), an effect that may last up to 6 hours. And last, it is a possible freeradical scavenger. Despite these short-lived but beneficial effects, the administration of mannitol is not without risks. It opens the blood-brain barrier and can potentially draw fluid into the CNS and aggravate vasogenic cerebral edema. It should also be used cautiously with concomitant administration of steroids and phenytoin (Dilantin), as it may cause a nonketotic hyperosmolar state, with high mortality. With overuse, it can also result in hypertension and increased CBF if cerebral autoregulation is defective . . And last, high doses carry a significant risk for the development of acute renal failure , especially with coexisting sepsis, concomitant nephrotoxic drug use, serum osmolarity> 320, or preexisting kidney disease. Some patients with mass lesions on one side may not uniformly develop contralateral hemiparesis

Answer 10

**A. Shift of the brainstem away frol11 the mass producing compression of the contralateral cerebral peduncle against the tentorium ** B. The patient lil{ely suffered a Duret hemorrhage C. There was likely a contusion in the underlying motor cortex on the contralateral side that was not detected on the initial CT scan D. The patient likely had a left internal ca rotid artery dissection that subsequently showered emboli to the distal vasculature E. There was an associated fracture of the transverse foramen on the left, which produced a vertebral artery dissection and small infarct in the ventral pons ## Footnote Current head injury research guidelines suggest that mannitol and hyperventilation may exacerbate cerebral ischemia after head injury. However, mannitol and hyperventilation are recommended for those patients with acute head injury as a temporary measure to control elevated intracranial pressure. Hyperventilation may be commenced immediately, but mannitol should be withheld until the primary survey is complete and adequate intravascular volume and urine output are realized. The mechanism of action of mannitol is still debated, but it is believed to have the follOWing beneficial effects. First, it acts to immediately expand the plasma by reducing hematocrit and blood viscosity (improved rheology), which improves CBF and O2 delivery. This reduces ICP very quicldy, which is most marked in patients with CPP < 70 mm r-rg. Second, it draws edema from the adjacent cerebral parenchyma into the intravascular compartment (osmotic effect), an effect that may last up to 6 hours. And last, it is a possible freeradical scavenger. Despite these short-lived but beneficial effects, the administration of mannitol is not without risks. It opens the blood-brain barrier and can potentially draw fluid into the CNS and aggravate vasogenic cerebral edema. It should also be used cautiously with concomitant administration of steroids and phenytoin (Dilantin), as it may cause a nonketotic hyperosmolar state, with high mortality. With overuse, it can also result in hypertension and increased CBF if cerebral autoregulation is defective . . And last, high doses carry a significant risk for the development of acute renal failure , especially with coexisting sepsis, concomitant nephrotoxic drug use, serum osmolarity> 320, or preexisting kidney disease. Some patients with mass lesions on one side may not uniformly develop contralateral hemiparesis

Answer 11

A. 1,2, and 3 are correct B. 1 and 3 are correct C. 2 and 4 are correct D. Only 4 is correct **E. All of the above ** ## Footnote Current head injury research guidelines suggest that mannitol and hyperventilation may exacerbate cerebral ischemia after head injury. However, mannitol and hyperventilation are recommended for those patients with acute head injury as a temporary measure to control elevated intracranial pressure. Hyperventilation may be commenced immediately, but mannitol should be withheld until the primary survey is complete and adequate intravascular volume and urine output are realized. The mechanism of action of mannitol is still debated, but it is believed to have the follOWing beneficial effects. First, it acts to immediately expand the plasma by reducing hematocrit and blood viscosity (improved rheology), which improves CBF and O2 delivery. This reduces ICP very quicldy, which is most marked in patients with CPP < 70 mm r-rg. Second, it draws edema from the adjacent cerebral parenchyma into the intravascular compartment (osmotic effect), an effect that may last up to 6 hours. And last, it is a possible freeradical scavenger. Despite these short-lived but beneficial effects, the administration of mannitol is not without risks. It opens the blood-brain barrier and can potentially draw fluid into the CNS and aggravate vasogenic cerebral edema. It should also be used cautiously with concomitant administration of steroids and phenytoin (Dilantin), as it may cause a nonketotic hyperosmolar state, with high mortality. With overuse, it can also result in hypertension and increased CBF if cerebral autoregulation is defective . . And last, high doses carry a significant risk for the development of acute renal failure , especially with coexisting sepsis, concomitant nephrotoxic drug use, serum osmolarity> 320, or preexisting kidney disease. Some patients with mass lesions on one side may not uniformly develop contralateral hemiparesis

Answer 12

A. 1,2, and 3 are correct B. 1 and 3 are correct **C. 2 and 4 are correct ** D. Only 4 is correct E. All of the above ## Footnote Current head injury research guidelines suggest that mannitol and hyperventilation may exacerbate cerebral ischemia after head injury. However, mannitol and hyperventilation are recommended for those patients with acute head injury as a temporary measure to control elevated intracranial pressure. Hyperventilation may be commenced immediately, but mannitol should be withheld until the primary survey is complete and adequate intravascular volume and urine output are realized. The mechanism of action of mannitol is still debated, but it is believed to have the follOWing beneficial effects. First, it acts to immediately expand the plasma by reducing hematocrit and blood viscosity (improved rheology), which improves CBF and O2 delivery. This reduces ICP very quicldy, which is most marked in patients with CPP < 70 mm r-rg. Second, it draws edema from the adjacent cerebral parenchyma into the intravascular compartment (osmotic effect), an effect that may last up to 6 hours. And last, it is a possible freeradical scavenger. Despite these short-lived but beneficial effects, the administration of mannitol is not without risks. It opens the blood-brain barrier and can potentially draw fluid into the CNS and aggravate vasogenic cerebral edema. It should also be used cautiously with concomitant administration of steroids and phenytoin (Dilantin), as it may cause a nonketotic hyperosmolar state, with high mortality. With overuse, it can also result in hypertension and increased CBF if cerebral autoregulation is defective . . And last, high doses carry a significant risk for the development of acute renal failure , especially with coexisting sepsis, concomitant nephrotoxic drug use, serum osmolarity> 320, or preexisting kidney disease. Some patients with mass lesions on one side may not uniformly develop contralateral hemiparesis

Answer 13

A. Head trauma **B. Infection ** C. Genetic predisposition D. Collagen vascular disease E. Hypertension ## Footnote Mycotic or infective aneurysms account for about 4% of intracranial aneurysms and are most commonly found along the distribution of the distal middle cerebral artery (MCA). Patients with head trauma also are at risk of developing aneurysms, although these are most frequently located along the distal anterior cerebral artery distribution. Mycotic aneurysms occur in about 3 to 15% of patients with subacute bacte rial endoca rditis (SBE), and the most com1110n organism isolated from the blood is Streptococclis viTidans species. Patients that are IV drug abusers or immunodeficient (HIV) are at increased risk of developing

Answer 14

A. Alcoholism B. Ehlers-Danlos disease **C. Subacute bacterial endocarditis** D. Marfan's syndrome E. Polycystic kidney disease ## Footnote Mycotic or infective aneurysms account for about 4% of intracranial aneurysms and are most commonly found along the distribution of the distal middle cerebral artery (MCA). Patients with head trauma also are at risk of developing aneurysms, although these are most frequently located along the distal anterior cerebral artery distribution. Mycotic aneurysms occur in about 3 to 15% of patients with subacute bacte rial endoca rditis (SBE), and the most com1110n organism isolated from the blood is Streptococclis viTidans species. Patients that are IV drug abusers or immunodeficient (HIV) are at increased risk of developing

Answer 15

A. Observation followed by repeat angiography in 6 months **B. Antibiotics followed by repeat angiography ** C. Emergent surgery D. Stentlcoiling followed by blood pressure control E. Steroids ## Footnote Mycotic or infective aneurysms account for about 4% of intracranial aneurysms and are most commonly found along the distribution of the distal middle cerebral artery (MCA). Patients with head trauma also are at risk of developing aneurysms, although these are most frequently located along the distal anterior cerebral artery distribution. Mycotic aneurysms occur in about 3 to 15% of patients with subacute bacte rial endoca rditis (SBE), and the most com1110n organism isolated from the blood is Streptococclis viTidans species. Patients that are IV drug abusers or immunodeficient (HIV) are at increased risk of developing

Answer 16

A. Observation B. Placement of a subgaleal shunt C. Placement of a ventriculoperitoneal shunt followed by endoscopic third ventriculostomy if shunting fails **D. EndoscopiC third ventriculostomy ** E. EndoscopiC third ventriculostomy followed by septostomy ## Footnote ETV is a commonly performed procedure for patients with aqueductal stenosis (AS). Although there is some controversy about the age at which this procedure should first be employed, results indicate high success rates for properly selected patients. Complications of shunting may include slit ventricle syndrome, intracranial hypotension, subdural hematomas, craniosynostosis, microcephaly, and overdrainage, which are typically not noted after endoscopy. The precise location to fenestrate the floor of the third ventricle may vary on a case-by-case baSiS, but perforating the floor anterior to the mamillary bodies and posterior to the infundibulum seems to a popular approach . Performing a septostomy in conjunction to a third ventriculostomy does not improve results in patients with AS, as the obstruction is downstream to the foramen of Monro. A patient with scarring or a cyst obstructing one foramen of Monro would likely benefit from this ancillary procedure. Predicting the success rate of ETV by preoperative imaging studies has proven to be very difficult, although identifying relevant anatomy (thickness of the floor of the third ventricle, location of basilar artery) to help guide the operation has proven to be effective (Kaye and Blacl~, pp. 789- 797; Youmans, pp. 3429- 3430; Will~ins, pp. 541-542).

Answer 17

A. Lower rate of subdural hematoma formation with ETV **B. Higher rate of craniosynostosis with ETV ** C. Lower infection rate with ETV D. Physiologic CSF diversion with ETV E. Higher chance of overdrainage with shunt placement ## Footnote ETV is a commonly performed procedure for patients with aqueductal stenosis (AS). Although there is some controversy about the age at which this procedure should first be employed, results indicate high success rates for properly selected patients. Complications of shunting may include slit ventricle syndrome, intracranial hypotension, subdural hematomas, craniosynostosis, microcephaly, and overdrainage, which are typically not noted after endoscopy. The precise location to fenestrate the floor of the third ventricle may vary on a case-by-case baSiS, but perforating the floor anterior to the mamillary bodies and posterior to the infundibulum seems to a popular approach . Performing a septostomy in conjunction to a third ventriculostomy does not improve results in patients with AS, as the obstruction is downstream to the foramen of Monro. A patient with scarring or a cyst obstructing one foramen of Monro would likely benefit from this ancillary procedure. Predicting the success rate of ETV by preoperative imaging studies has proven to be very difficult, although identifying relevant anatomy (thickness of the floor of the third ventricle, location of basilar artery) to help guide the operation has proven to be effective (Kaye and Blacl~, pp. 789- 797; Youmans, pp. 3429- 3430; Will~ins, pp. 541-542).

Answer 18

**A. It is relatively straightforward to accurately determine the future function of the subarachnoid pathways and patency of the ETV as long as a high resolution MR cisternogram is obtained preoperatively that identifies the level of the block ** B. MRI can accurately delineate the anatomy of the foramen oOdonro, third ventricle, and massa intermedia C. The position of the basilar artery and the thiclmess of the third ventricular floor can be verified on most preoperative MRIs D. A prior history of CSF infection may decrease the success rate of ETV E. A prior history of a shunt is not an absolute contraindication for ETV ## Footnote ETV is a commonly performed procedure for patients with aqueductal stenosis (AS). Although there is some controversy about the age at which this procedure should first be employed, results indicate high success rates for properly selected patients. Complications of shunting may include slit ventricle syndrome, intracranial hypotension, subdural hematomas, craniosynostosis, microcephaly, and overdrainage, which are typically not noted after endoscopy. The precise location to fenestrate the floor of the third ventricle may vary on a case-by-case baSiS, but perforating the floor anterior to the mamillary bodies and posterior to the infundibulum seems to a popular approach . Performing a septostomy in conjunction to a third ventriculostomy does not improve results in patients with AS, as the obstruction is downstream to the foramen of Monro. A patient with scarring or a cyst obstructing one foramen of Monro would likely benefit from this ancillary procedure. Predicting the success rate of ETV by preoperative imaging studies has proven to be very difficult, although identifying relevant anatomy (thickness of the floor of the third ventricle, location of basilar artery) to help guide the operation has proven to be effective (Kaye and Blacl~, pp. 789- 797; Youmans, pp. 3429- 3430; Will~ins, pp. 541-542).

Answer 19

A. Posterior to the mammillary bodies B. Anterior to the infundibular recess, posterior to the prechiasmatic space C. In the most translucent area of the floor of the third ventricle **D. Anterior to the mammillary bodies, posterior to the infundibular recess ** E. Anterior to the pulsations of the basilar artery ## Footnote ETV is a commonly performed procedure for patients with aqueductal stenosis (AS). Although there is some controversy about the age at which this procedure should first be employed, results indicate high success rates for properly selected patients. Complications of shunting may include slit ventricle syndrome, intracranial hypotension, subdural hematomas, craniosynostosis, microcephaly, and overdrainage, which are typically not noted after endoscopy. The precise location to fenestrate the floor of the third ventricle may vary on a case-by-case baSiS, but perforating the floor anterior to the mamillary bodies and posterior to the infundibulum seems to a popular approach . Performing a septostomy in conjunction to a third ventriculostomy does not improve results in patients with AS, as the obstruction is downstream to the foramen of Monro. A patient with scarring or a cyst obstructing one foramen of Monro would likely benefit from this ancillary procedure. Predicting the success rate of ETV by preoperative imaging studies has proven to be very difficult, although identifying relevant anatomy (thickness of the floor of the third ventricle, location of basilar artery) to help guide the operation has proven to be effective (Kaye and Blacl~, pp. 789- 797; Youmans, pp. 3429- 3430; Will~ins, pp. 541-542).

Answer 20

A. Pedicle B. Superior articular facet **C. Inferior articular facet ** D. Vertebral body E. Spinal canal/thecal sac ## Footnote Compression of nerve roots in the lateral recess (lateral recess syndrome) can occur between a hypertrophied superior articular facet (dorsally), the pedicle (laterally), and the inferior vertebral body (ventrally). Medially, the lateral recess opens toward the spinal canal/thecal sac. The characteristic feature of lateral recess syndrome is that of radicular symptoms that occur mainly when the patient is walking or standing and are relieved by Sitting, squatting forward, lying on either side, andlor postures that accentuate lumbar kyphosis. This is opposite to what is seen with patients harboring discogenic disease , who are uncomfortable while sitting. With the lateral recess syndrome, adequate decompression involves laminectomy with resec tion of the medial third of the hypertrophied facet (media l facetectomy), which is usually the superior articular process (Wi ll in s, pp. 3841- 3845).

Answer 21

A. Inferior articular process B. Pedicle **C. Superior articular process ** D. Ligamentum flavum hypertrophy E. Vertebral body ## Footnote Compression of nerve roots in the lateral recess (lateral recess syndrome) can occur between a hypertrophied superior articular facet (dorsally), the pedicle (laterally), and the inferior vertebral body (ventrally). Medially, the lateral recess opens toward the spinal canal/thecal sac. The characteristic feature of lateral recess syndrome is that of radicular symptoms that occur mainly when the patient is walking or standing and are relieved by Sitting, squatting forward, lying on either side, andlor postures that accentuate lumbar kyphosis. This is opposite to what is seen with patients harboring discogenic disease , who are uncomfortable while sitting. With the lateral recess syndrome, adequate decompression involves laminectomy with resec tion of the medial third of the hypertrophied facet (media l facetectomy), which is usually the superior articular process (Wi ll in s, pp. 3841- 3845).

Answer 22

**A. Pain in the lateral recess syndrome is exacerbated by walking or standing** B. Failure of coughing or sneezing to aggravate pain in discogenic disease C. Positive straight leg raising in lateral recess syndrome D. Pain in lateral recess syndrome is relieved by postures accentuating lumbar lordosis E. There is a slightly higher incidence of bladder incontinence with lateral recess stenosis ## Footnote Compression of nerve roots in the lateral recess (lateral recess syndrome) can occur between a hypertrophied superior articular facet (dorsally), the pedicle (laterally), and the inferior vertebral body (ventrally). Medially, the lateral recess opens toward the spinal canal/thecal sac. The characteristic feature of lateral recess syndrome is that of radicular symptoms that occur mainly when the patient is walking or standing and are relieved by Sitting, squatting forward, lying on either side, andlor postures that accentuate lumbar kyphosis. This is opposite to what is seen with patients harboring discogenic disease , who are uncomfortable while sitting. With the lateral recess syndrome, adequate decompression involves laminectomy with resec tion of the medial third of the hypertrophied facet (media l facetectomy), which is usually the superior articular process (Wi ll in s, pp. 3841- 3845).

Answer 23

A. Laminectomy **B. Laminectomy with resection of the medial third of the hypertrophied facet (medial facetectomy) ** C. Microdiscectomy D. Laminectomy and fusion E. None of the above ## Footnote Compression of nerve roots in the lateral recess (lateral recess syndrome) can occur between a hypertrophied superior articular facet (dorsally), the pedicle (laterally), and the inferior vertebral body (ventrally). Medially, the lateral recess opens toward the spinal canal/thecal sac. The characteristic feature of lateral recess syndrome is that of radicular symptoms that occur mainly when the patient is walking or standing and are relieved by Sitting, squatting forward, lying on either side, andlor postures that accentuate lumbar kyphosis. This is opposite to what is seen with patients harboring discogenic disease , who are uncomfortable while sitting. With the lateral recess syndrome, adequate decompression involves laminectomy with resec tion of the medial third of the hypertrophied facet (media l facetectomy), which is usually the superior articular process (Wi ll in s, pp. 3841- 3845).

Answer 24

A. Cordotomy B. Periaqueductal gray stimulation C. Percutaneous trigeminal electrocautery D. Sympathectomy **E. Bilateral thalamotomy ** F. Pallidotomy G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 25

A. Cordotomy B. Periaqueductal gray stimulation C. Percutaneous trigeminal electrocautery D. Sympathectomy E. Bilateral thalamotomy **F. Pallidotomy ** G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 26

**A. Cordotomy ** B. Periaqueductal gray stimulation C. Percutaneous trigeminal electrocautery D. Sympathectomy E. Bilateral thalamotomy F. Pallidotomy G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 27

A. Cordotomy **B. Periaqueductal gray stimulation ** C. Percutaneous trigeminal electrocautery D. Sympathectomy E. Bilateral thalamotomy F. Pallidotomy G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 28

A. Cordotomy B. Periaqueductal gray stimulation C. Percutaneous trigeminal electrocautery **D. Sympathectomy ** E. Bilateral thalamotomy F. Pallidotomy G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 29

A. Cordotomy B. Periaqueductal gray stimulation **C. Percutaneous trigeminal electrocautery ** D. Sympathectomy E. Bilateral thalamotomy F. Pallidotomy G. ComIllisuralmyelotomy ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 30

A. Cordotomy B. Periaqueductal gray stimulation C. Percutaneous trigeminal electrocautery D. Sympathectomy E. Bilateral thalamotomy F. Pallidotomy **G. ComIllisuralmyelotomy ** ## Footnote Direct sectioning of the spinothalamiC tract (cordotomy) is very effective for unilateral pain below the upper chest region, however, it is associated with many complications and is usually performed only in terminal patients. Complications of cordotomy include hemiparesis, respiratory depression (Ondine's curse with bilateral procedures), and dysesthesias. Midline myelotomies can also be performed to interrupt the decussating fibers of the spinothalamic tract. This can be quite effective in the treatment of chronic pelvic pain secondary to cancer but is associated with leg wealmess, dysesthesias, and bladder dysfunction. Chronic deep brain stimulation of the VPL and VPM nuclei of the thalamus as well as the periaqueductal gray (PAG) has been performed in the treatment of thalamic pain states, postherpetic neuralgia, and causalgia. Stimulation of the PAG has been associated with eye movement disorders, pupillary dilation, and the feeling of fear. Complications of pallidotomy include injury to the adjacent internal capsule (hemiparesis) and optic tract (homonymous hemianopsia), while complications of bilateral thalamotomy include speech problems and congnitive decline. Horner's syndrome, pneumothorax, intercostal neuralgias, and spinal cord injury can occur after sympathectomy, while anesthesia dolorosa has been reported to occur after percutaneous trigeminal electrocautery (Kaye and Blacl~, pp. 1431-1445, 1481; Greenberg, pp. 352- 354, 361, 365-370, 373-380; Youmans, pp.3025-3030,3045- 3048,3067- 3070,3101- 3102; Will~ins, pp. 4055-4059).

Answer 31

A. Glycerol rhizolysis **B. Balloon decompression ** C. Radiofrequency thermocoagulation D. i'l'licrovascular decompression E. Peripheral alcohol injection ## Footnote Peripheral alcohol injection, glycerol rhizolysis, radiofrequency thermocoagulation, and microvascular decompression are all established procedures for the treatment of trigeminal neuralgia. Peripheral balloon compression instead of decompression is a modification of the observation that open surgical decompression of the ganglion could lead to significant pain relief in trigeminal neuralgia (Kaye and Blacl~, pp. 1616-1633; Greenberg, pp. 373-380).

Answer 32

A. The evaluation of craniocervical stability **B. EMG and nerve conduction studies (NCS) to identify the extent of peripheral nerve damage ** C. Whether there is an associated syrinx D. The extent of ventral compression E. Presence of abnormal ossification centers and epipbyseal growth plates in children, as this may alter trea tment strategies ## Footnote Craniocervical junction (CCJ) abnormalities can often be very difficult to manage, with the primary goal being to relieve the compression at the cervicomedullary junction. They are commonly seen in patients with Chiari malformation or rheumatoid arthritis. With reducible lesions, stabilization is essential to maintain neural decompression, while for irreducible lesions, decompression at the site of encroachment (ventral or posterior) as well as stabilization are often required. Patients with rheumatoid arthritis are at risk for developing atlantoaxial instability (AAI); superior migration of the odontoid process (SMO), also lmown as cranial settling; and subaxial subluxations (SAS). For rheumatoid patients with reducible leSions, immobilization alone with posterior spinal or craniospinal fusion without decompressive procedures is the mainstay of treatment. Late-onset deterioration in patients with rheumatoid arthritis or Chiari malformations in the pattern seen in this patient is concerning for syritL\: or syringomyelia formation (Kaye and Blacl~, pp. 1755-1770; Will~ins, pp. 3789- 3790; Youmans, pp. 4569- 4580).

Answer 33

A. Posterior cervical laminectomy B. Posterior cervical laminectomy, suboccipital craniectomy, and fusion C. Cervical traction for another week to attempt to further reduce the abnormality before embarking on any surgical procedure **D. Immobilization alone with posterior cervical fusion without a decompression ** E. Transoral odontectomy followed by posterior cervical decompression, suboccipital craniectomy, and fusion ## Footnote Craniocervical junction (CCJ) abnormalities can often be very difficult to manage, with the primary goal being to relieve the compression at the cervicomedullary junction. They are commonly seen in patients with Chiari malformation or rheumatoid arthritis. With reducible lesions, stabilization is essential to maintain neural decompression, while for irreducible lesions, decompression at the site of encroachment (ventral or posterior) as well as stabilization are often required. Patients with rheumatoid arthritis are at risk for developing atlantoaxial instability (AAI); superior migration of the odontoid process (SMO), also lmown as cranial settling; and subaxial subluxations (SAS). For rheumatoid patients with reducible leSions, immobilization alone with posterior spinal or craniospinal fusion without decompressive procedures is the mainstay of treatment. Late-onset deterioration in patients with rheumatoid arthritis or Chiari malformations in the pattern seen in this patient is concerning for syritL\: or syringomyelia formation (Kaye and Blacl~, pp. 1755-1770; Will~ins, pp. 3789- 3790; Youmans, pp. 4569- 4580).

Answer 34

A. CT of the brain to look for hydrocephalus B. EMG and NCS to identify the extent of peripheral nerve damage **C. Screening MRI of the spine ** D. Bladder urodynamic testing E. Dynamic films of the cervical spine to evaluate for pseudoarthrosis and instability ## Footnote Craniocervical junction (CCJ) abnormalities can often be very difficult to manage, with the primary goal being to relieve the compression at the cervicomedullary junction. They are commonly seen in patients with Chiari malformation or rheumatoid arthritis. With reducible lesions, stabilization is essential to maintain neural decompression, while for irreducible lesions, decompression at the site of encroachment (ventral or posterior) as well as stabilization are often required. Patients with rheumatoid arthritis are at risk for developing atlantoaxial instability (AAI); superior migration of the odontoid process (SMO), also lmown as cranial settling; and subaxial subluxations (SAS). For rheumatoid patients with reducible leSions, immobilization alone with posterior spinal or craniospinal fusion without decompressive procedures is the mainstay of treatment. Late-onset deterioration in patients with rheumatoid arthritis or Chiari malformations in the pattern seen in this patient is concerning for syritL\: or syringomyelia formation (Kaye and Blacl~, pp. 1755-1770; Will~ins, pp. 3789- 3790; Youmans, pp. 4569- 4580).

Answer 35

A. 2 **B. 3 ** C. 4 D. 5 E. 6 ## Footnote The stylOid process gives rise to the stylohyoid (VII), styloglossus (XII), and stylopharyngeal muscles (IX) of the visceral neck as well as the stylomandibular and stylohyoid ligaments. It is a remnant of the second brachial arch (Youmans, p. 36).

Answer 36

A. VII, IX **B. VII, IX, XII ** C. IX, X, XII D. V, VII, IX E. X, XII ## Footnote The stylOid process gives rise to the stylohyoid (VII), styloglossus (XII), and stylopharyngeal muscles (IX) of the visceral neck as well as the stylomandibular and stylohyoid ligaments. It is a remnant of the second brachial arch (Youmans, p. 36).

Answer 37

A. 1 B. 2 **C. 3 ** D. 4 E. 5 ## Footnote The stylOid process gives rise to the stylohyoid (VII), styloglossus (XII), and stylopharyngeal muscles (IX) of the visceral neck as well as the stylomandibular and stylohyoid ligaments. It is a remnant of the second brachial arch (Youmans, p. 36).

Answer 38

B ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 39

A ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 40

C ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 41

A ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 42

C ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 43

F ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 44

A ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 45

D ## Footnote Fracture of the proximal humerus (A) can result in injury to the axillary nerve (C5-6), which innervates the teres minor and deltoid muscles. This can result in sensory loss at the shoulder as well as shoulder abduction wealmess. There is also a chance of concomitant brachial plexus injury with such a fracture due to the proximity of the proximal humerus to the brachial plexus. The radial nerve runs down the posterior aspect of the arm and is at risk for injury during fractures of the midhumeral shaft as it winds around the spiral groove (8). This could cause paralysis of the wrist and hand extensor muscles. Since the fibers that innervate the triceps muscle often arise proximal to the spiral groove, extension of the forearm may not be affected by midhumeral fractures, and some supination is possible due to an intact biceps brachii muscle. Fracture in the vicinity of the medial epicondyle may result in ulnar nerve damage only (C), which can produce wealmess of flexion and adduction of wrist, pa ralysis of hypothenar muscles and most deep muscles of the hand, as well as some weakness in select thenar muscles. Injury of the ulnar nerve by fracture of the distal ulna can result in wealmess or paralysis of hypothenar, some thenar, and intrinsic hand muscles but often spares innervation of the wrist (flexion, adduction), since these nerves often arise more proximally. If there is also a concomitant distal radial fracture, injury to the median nerve may accompany the ulnar nerve injury (F) and produce loss of sensation of the lateral side of the palm without sensory loss on the palmar sides of the first, second, and third digits (superficial branch of the median nerve) as well as marked weakness of thumb

Answer 46

A. There is a 30% chance that she will develop diabetes insipidus **B. The most serious and disabling probl em is the development of obesity, which occurs in about 50% of these patients after surgery ** C. Approximately 90% of patients will not require maintenance corticosteroid and thyroid replacement therapy D. Approximately 10% of patients will require growth hormone replacement therapy E. The endocrine outcome after surgery is very unpredictable ## Footnote A significant number of children with craniopharyngiomas will have a significant endocrine abnormality after surgery, which is quite predictable, The most serious complication appears to be obesity, which develops in about 50% of patients, These patients are unable to control their appetite secondary to damage to the hypothalamic satiety center. Growth hormone may benefit these patients, as it appears to reduce body fat and increase lean body mass, Nearly 50% of patients will require GIl-replacement therapy, Diabetes insipidus occurs in about 90% of patients and is often permanent. Moreover, about 90% of patients will require hydrocortisone and thyroid replacement therapy after surgery (Kaye and Blacl{, pp. 741- 748; Committee on Education in Neurological Surgery, pp, 26, 116; Curtis et aI., pp.24- 27),

Answer 47

A. The headaches often resemble a post-lumbar puncture headache B. MRI scans with contrast may reveal enhancement of the dura over the cerebral and cerebellar convexities **C. Spontaneous improvement is rarely seen, since CSF leal{s are often identified adjacent to nerve roots ** D. Spinal fluid may reveal elevated protein and pleocytosis E. Analgesics containing caffeine may be helpful ## Footnote The headaches of spontaneous intracranial hypotension often resemble post-lumbar puncture headaches, Ileadaches are usually worse in the upright position and are generally relieved when the patient is lying down, The diagnosis is established by lumbar puncture, which reveals low opening pressure or dry tap, It is not uncommon to have elevated protein and pleocytosis, It is postulated that this syndrome results from leakage of CSF to the outside neuraxis, often around nerve roots, MR cisternography is often capable of demonstrating the leak. Jugular compression will elevate intracranial pressure but usually makes the headache worse , suggesting that low pressure may not be the only factor responsible for the headaches, MRl scans often reveal dural enhancement over the cerebral and cerebellar convexities, tentorium, and fa lx, which usually resolves with resolution of the symptoms, Treatment should be conservative, since there is often spontaneous improvement. Analgesics containing caffeine and adequate hydration seem to help, In some cases an epidural patch may be required; surgical closure of the fistula is rarely required (Committee on Education in Neurological Surgery, pp. 17, 105; Kosmoslw, pp, 79- 83)

Answer 48

A. A 3-CI11'1 arteriovenous malformation in the brainstem B. A l-cm right frontal and 2-cl11 left parietal metastatic carcinoma from the lung C. Recurrent glioblastoma of the left temporal lobe (2 C111J ) **D. A l-cm cavernoma of the right caudate nucleus that previously hemorrhaged ** E. Bilateral thalamic arteriovenous malformations (3 cmJ ) ## Footnote A long history of radiosurgical treatment for arteriovenous malformations exists, The best responses are often obtained for lesions with volumes less than 4 cnl", Multiple metastatic lesions are also amenable to this treatment modality, as are recurrent gliomas located in a variety of locations including the brainstem, thalamus, or other eloquent areas, There is, however, controversy about the radiosurgical treatment of cavernomas, While disease control has been documented, some authors are concerned with the potential of treatment-related complications such as recurrent hemorrhage after radiosurgery (Committee on Education in Neurological Surgery, pp, 108-109; Friedman, pp, 832- 841; Lunsford, pp, 404-444; Blacl{, pp. 367S-369S)

Answer 49

A. Stimulation of the periaqueductal gray B. Prefrontal lobotomy C. Cingulotomy **D. Hippocampectomy** E. Ventrolateral cordotomy ## Footnote Prefrontal lobectomy, cingulotomy, ventrolateral cordotomy, and periaqueductal gray stimulation may interrupt pain pathways or the response to painful stimuli, Hippocampectomy does not interrupt these pathways but may decrease the severity of complex partial seizures (Youmans, pp. 3025- 3030; Greenberg, pp. 364-370),

Answer 50

**A. Thalamic stimulation ** B. Subthalamic nucleus stimulation C . . Motor cortex stimulation D. Capsulotomy E. Multiple subpial transections ## Footnote Traumatic injury to the brainstem including the superior cerebellar peduncles and their connections can result in severe tremor that may be delayed by weeks to months following the brain injury, In some cases, improvement or resolution occurs spontaneously, so some authors have reconuuended a period of observation before considering surgery, The largest published series for secondary tremors is among patients with multiple sclerosiS, although a growing body of information is now available for patients with posttraumatic tremors, "'ith posttraumatic tremors, thalamic stimulation (Vim) may be considered for those who are refractory to medical management, although results have been mL'(ed, Thalamotomy is another treatment option for this group of patients, although postoperative dysarthria or worsening pre-existing dysarthria is an especially troubling complication in some of these studies (Tarsy, pp, 244- 254; Youmans, pp. 2748-2750),

Answer 51

A. Increased blood viscosity B. Hyperglycemia C. Decreased corticosteroid release D. Complement-mediated pneumonitis **E. Hypercoagulable state** ## Footnote Profound hypothermia during Circulatory arrest can result in various physiologic effects including increasing blood viscosity, metabolic acidosis (underperfused tissue), hyperglycemia (secondary to hypoinsulinemia), deCl'eased corticosteroid secretion, complement-mediated pneumonitis, renal failure (due to transient decrease in glomerular filtration rate, hemolysis, and blood product reactions), hepatic failure , and hypothermia-induced coagulopathy (due to platelet dysfunction and slowing of the enzymatic clotting cascade) (Youmans, p. 1532),

Answer 52

A. Neckpain **B. Cervical bruit ** C. Contralateral arm weakness or numbness D. Dysesthesia E. Transient vision losS ## Footnote The most cOl11mon ph);sical manifestation of extracranial carotid artery disease is a cervical bruit. The degree of stenosis necessary to produce a bruit has been reported to be as low as 25%, but in various studies its presence has been found to indicate a significant level (> 50%) of stenosis on angiography in at least 70% of patients, False-positive rates of 10 to 40% and false-negative rates of 30 to 70% have been reported for cervical bruits. The Framingham Study found that the risk of stroke and TlAs in patients with bruits was two to three times the risk for patients without bruits, Such patients were also about 2,5 times more likely to have a heart attack and l. 9 times more likely to die during the study period (Youmans, p. 1622).

Answer 53

A. Echinococcus infection **B. Neurocysticercosis ** C. Oryptococcus infection D. Cytomegalovirus infection E. Trichinosis ## Footnote Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system (CNS) worldwide. Humans are the definitive host for the adult tapeworm Taenia so/iwn, which thrives in the small intestine without consequence. Fecal shedding of eggs usually leads to ingestion of eggs in contaminated water or food by an intermediate host, typically humans or pig. Once inside the intestine, the eggs are released and produce primary larvae that enter the Circulatory system. Hematogenous spread to muscular, ocular, and neural tissue then occurs. Once inside the brain, the primary larvae develop into secondary larvae, the cysticerci. Clinical manifestations of the neural form of the disease are varied and nonspecific. This pleomorphism is related to the number, size, and topography of the lesions. Parenchymal disease (as in this case) is most common and presents with seizures in 50 to 80% of patients. Treatment typically includes antiepileptics, albendazole, or praziquantel , as well as a short course of steroids to reduce the inflammatory reaction during antihelminthic treatment. Niclosamide may be given orally to treat adult tapeworms in the GI tract. Fluconazole is an antifungal and not used to treat this disease process. The colonization of the ventricular system often presents with rapid clinical deterioration due to increased intracranial pressure from obstructive hydrocephalus. There is still controversy about the best treatment for this form of the disease, but most authors advocate either a trial of antihelminthic medication, endoscopic cyst resection, or microsurgery. Subarachnoid disease is usually more difficult to manage because the cysts are usually multiple, attain larger sizes, and produce severe basal meningitis, but antihelminthic medications are typically first-line therapy for this form of the disease. From the many tests performed, current data indicate that enzyme-linked immunosorbent assay (ELISA) and electroimmunotransfer blot (EITB) tests are the most effective laboratory tests for diagnosis. Peripheral white blood cells, ova and parasites in stool, and eosinophilia are inconsistent and unreliable markers of disease. This patient also harbored a fourth ventricular cyst and obstructive hychocephalus, which accounts for the rounded third ventricle (Greenberg, pp. 236- 239)

Answer 54

A. Headaches B. Obtundation C. Cranial nerve palsies D. Fevers **E. Seizure ** ## Footnote Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system (CNS) worldwide. Humans are the definitive host for the adult tapeworm Taenia so/iwn, which thrives in the small intestine without consequence. Fecal shedding of eggs usually leads to ingestion of eggs in contaminated water or food by an intermediate host, typically humans or pig. Once inside the intestine, the eggs are released and produce primary larvae that enter the Circulatory system. Hematogenous spread to muscular, ocular, and neural tissue then occurs. Once inside the brain, the primary larvae develop into secondary larvae, the cysticerci. Clinical manifestations of the neural form of the disease are varied and nonspecific. This pleomorphism is related to the number, size, and topography of the lesions. Parenchymal disease (as in this case) is most common and presents with seizures in 50 to 80% of patients. Treatment typically includes antiepileptics, albendazole, or praziquantel , as well as a short course of steroids to reduce the inflammatory reaction during antihelminthic treatment. Niclosamide may be given orally to treat adult tapeworms in the GI tract. Fluconazole is an antifungal and not used to treat this disease process. The colonization of the ventricular system often presents with rapid clinical deterioration due to increased intracranial pressure from obstructive hydrocephalus. There is still controversy about the best treatment for this form of the disease, but most authors advocate either a trial of antihelminthic medication, endoscopic cyst resection, or microsurgery. Subarachnoid disease is usually more difficult to manage because the cysts are usually multiple, attain larger sizes, and produce severe basal meningitis, but antihelminthic medications are typically first-line therapy for this form of the disease. From the many tests performed, current data indicate that enzyme-linked immunosorbent assay (ELISA) and electroimmunotransfer blot (EITB) tests are the most effective laboratory tests for diagnosis. Peripheral white blood cells, ova and parasites in stool, and eosinophilia are inconsistent and unreliable markers of disease. This patient also harbored a fourth ventricular cyst and obstructive hychocephalus, which accounts for the rounded third ventricle (Greenberg, pp. 236- 239)

Answer 55

A. Borrelia bU"I-gd01:!'eri B. Echi:llOCOCCUS gnm:ulosa C. Toxoplasma gondi:i D. Trepollema pa/lidum **E. Taenia soi'ium ** ## Footnote Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system (CNS) worldwide. Humans are the definitive host for the adult tapeworm Taenia so/iwn, which thrives in the small intestine without consequence. Fecal shedding of eggs usually leads to ingestion of eggs in contaminated water or food by an intermediate host, typically humans or pig. Once inside the intestine, the eggs are released and produce primary larvae that enter the Circulatory system. Hematogenous spread to muscular, ocular, and neural tissue then occurs. Once inside the brain, the primary larvae develop into secondary larvae, the cysticerci. Clinical manifestations of the neural form of the disease are varied and nonspecific. This pleomorphism is related to the number, size, and topography of the lesions. Parenchymal disease (as in this case) is most common and presents with seizures in 50 to 80% of patients. Treatment typically includes antiepileptics, albendazole, or praziquantel , as well as a short course of steroids to reduce the inflammatory reaction during antihelminthic treatment. Niclosamide may be given orally to treat adult tapeworms in the GI tract. Fluconazole is an antifungal and not used to treat this disease process. The colonization of the ventricular system often presents with rapid clinical deterioration due to increased intracranial pressure from obstructive hydrocephalus. There is still controversy about the best treatment for this form of the disease, but most authors advocate either a trial of antihelminthic medication, endoscopic cyst resection, or microsurgery. Subarachnoid disease is usually more difficult to manage because the cysts are usually multiple, attain larger sizes, and produce severe basal meningitis, but antihelminthic medications are typically first-line therapy for this form of the disease. From the many tests performed, current data indicate that enzyme-linked immunosorbent assay (ELISA) and electroimmunotransfer blot (EITB) tests are the most effective laboratory tests for diagnosis. Peripheral white blood cells, ova and parasites in stool, and eosinophilia are inconsistent and unreliable markers of disease. This patient also harbored a fourth ventricular cyst and obstructive hychocephalus, which accounts for the rounded third ventricle (Greenberg, pp. 236- 239)

Answer 56

A. Blue rubber bleb nevus syndrome **B. Vein of Galen aneurysm ** C. Carotid-cavernous fistula D. Intracranial hemangioblastoma of infancy E. Sinus pericranii ## Footnote A neonate suffering high-output cardiac failure, hyperdynamic precordium, dilated cervical and cranial veins, and arteries with a "machine-like" bruit heard over the head and neck is most likely harboring a vein of Galen aneurysm. Vascular tumors, CC fistula, blue rubber bleb nevus syndrome, and sinus pericranii do not typically present with this constellation of problems. Although transcranial ultrasonography is an excellent way to diagnose these lesions, the "gold standard" is cerebral angiography. In infants, a transarterial and transvenous route to eliminate the high-flow shunt is often employed . This technique may not lead to complete obliteration but often converts highoutput cardiac failure to a persistent fistula. In an older child or adult, the treatment is frequently gradual and entails graded elimination of the shunt with endovascular surgery, usually via a transarterial route (Kaye and Blacl<, pp. 174- 176; Youmans, pp. 3433-3445).

Answer 57

A. Supinator B. Extensor carpi ulnaris C. Abductor pollicis longus D. Extensor cligitorum **E. Pronator quadratus ** ## Footnote The deep branch of the radial nerve passes through a slit in the supinator muscle (arcade of Frohse) to the posterior forearm. rVter passing this slit, the nerve is called the posterior interosseous nerve and supplies the supinator, extensor carpi radialis breviS, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensors pollicis longus and breviS, and extensor indicis muscles. The anterior interosseous nerve, a branch of the median nerve, supplies the pronator quadratus (Greenberg, pp. 523, 542- 543).

Answer 58

A. Combine multiple isocenters of irradiation in different planes B. Individual isocenters can be weighted variably to change their relative shape C. Individual radiation beams can be blocked to restrict dose away from critical structures, such as the optic chiasm D. A and B only **E. All of the above** ## Footnote The ability to create irregularly shaped radiosurgical volumes is important to achieve conformal irradiation of target tissue, as all tumors or lesions are rarely perfect spheres. The follOWing techniques can be used to create an irregularly shaped plan during radiosurgery. First, combine multiple isocenters of irradiation in different planes. For example, a series of 4-mm isocentors of irradiation is often used to tailor radiation to the porus acusticus for schwannomas. Second, individual isocenters can be weighted variably to change their relative shape. Finally, individual radiation beams can be blocked to restrict dose away from critical structures, such as the optic chiasm (Youmans, pp. 4118- 4119).

Answer 59

A. Sympathetic nerves ruuning along the carotid artery during neck dissection B. Injury of the T1 nerve root during the discectomy **C. Interruption of the sympathetic chain located on the ** anterior surface of the longus colli muscles D. Spinal cord injury during surgery E. A small hypothalamic infarct during surgery ## Footnote A rare complication after anterior cervical procedures is the development of a Horner's syndrome (anhidrosis, miosis, ptosis) from interruption of the sympathetic chain located on the anterior surface of the longus colli muscle. The thoracic duct enters the subclavian vein on the left and is particularly vulnerable to injury during left-sided anterior cervical procedures (Youmans, pp. 4442- 4443, 4451).

Answer 60

A. Inferior laryngeal nerve B. Thyrocervical artery **C. Thoracic duct ** D. C5 nerve root E. Dominant cardiac accelerator nerves ## Footnote A rare complication after anterior cervical procedures is the development of a Horner's syndrome (anhidrosis, miosis, ptosis) from interruption of the sympathetic chain located on the anterior surface of the longus colli muscle. The thoracic duct enters the subclavian vein on the left and is particularly vulnerable to injury during left-sided anterior cervical procedures (Youmans, pp. 4442- 4443, 4451).

Answer 61

A. Ll-2 B. L2-3 C. L3-4 **D. L4-5 ** E. L5-S1 ## Footnote Degenerative spondylolisthesis is most common in women at the L4-5 level, but may also be seen at the L3-4 level. Because this often occurs with sacralization of L5 in many patients, the facet degeneration may be explained as a hypermobility syndrome (Youmans, pp. 4545-4546)

Answer 62

**A. Transarticular screw fL'wtion and fusion if the lateral atlantalmasses are intact with good-quality bone ** B. Transoral odontectomy followed by posterior occipitalcervical decompression and fusion C. Laminectomy D. Transoral odontectomy followed by observation E. Halo placement ## Footnote Irreducible pathologic conditions affecting the cervicomedullary junction in patients with rheumatoid arthritis frequently require an anterior cervical procedure to remove the offending pathology (frequently pannus formation), followed by dorsal fL"ation and fusion. Reducible atlantoaxial dislocation is best managed by a posterior fusion and fL,,- ation procedure. Usually transarticular screw fL"ation is desirable if the bone quality is good and the lateral masses of the atlas are intact; but if this is not the case, placement of a rectangle of bone between the posterior arch of C2 and Cl followed by wiring may be an option. This, however, has been associated with higher failure rates in some studies These patients often required further reinforcement with cervical immobilization techniques such as halo placement. Dorsal occipitocervical fusion is almost always required for patients with rheumatoid cranial settling and in those following rheumatoid pannus resection. Transoral odontectomy with or without posterior fusion is not required for this patient since there was a reducible lesion. Laminectomy alone would likely further destabilize this patient, while halo placement without fusion would run a very high risk of failure (Youmans, pp. 4578- 4550; Wili(ins, pp. 3789- 3790).

Answer 63

A. Osteoconductive matrb:: B. Osteoinductive factors C. To support viable osteogenic cells D. Structural support **E. Osteoblasts for bone healing** ## Footnote The ideal bone graft provides the following elements for successful healing: osteoconductive matrix, osteoinductive factors, viable osteogenic cells, and structural support. Only fresh autografts contribute viable osteogenic cells to the developing fusion. Processed allografts frequently have no living cellular elements and are mainly derived from the tissues of the recipient bed (Youmans, pp. 4615-4616).

Answer 64

A. Ca 2+ B. Na+ C. CID. Ie **E. None of the above** ## Footnote Although traumatic brain injury (TBI) has been shown to result in increases of calcium flux into cells with subsequent cell injury, no clinical benefit has been observed in clinical trials attempting to attenuate this response in patients with TBI. A subset of patients with subarachnoid hemorrhage, however, did show a benefit. Calcium may enter cells via ion channels influenced by excitatory amino acids (glutamate, aspartate). Unfortunately clinical trials to antagonize these receptors have been discouraging in TBI (Youmans, pp. 5025- 5027).

Answer 65

A. Peripheral denervation B. Pallidotomy C. Thalamotomy D. Dorsal column stimulation **E. Motor cortex stimulation** ## Footnote Surgical therapies including cerebellar stimulation, dorsal column stimulation, peripheral denervation, thalamotomy, and pallidotomy have been used in the past to treat various forms of dystonia. Although the tha lamus has been the primary target for years, more recen tly many surgeons are targeting the globus pallidus with good results. Medications such as anticholinergics, muscle relaxants, and benzodiazepines are of limited use to patients. Botulism toxin is a safe and effective therapy for many focal dystonias but has not proven effective for patients with segmental dystonia, hemidystonia, or generalized dystonia (Youmans, pp. 2795-2801).

Answer 66

**A. Arcuate fasciculotomy ** B. Subcaudate tractotomy C. Limbic leukotomy D. Anterior capsulotomy E. Anterior cil1gulotomy ## Footnote The surgical management of psychiatric disease can be helpful for select patients with treatment-refractory major affective disorders, obsessive-compulsive disorder, and chronic anxiety states. Surgical interventions have included anterior capsulotomy, limbic leukotomy, subcaudate tractotomy, and anterior cingulotomy but not arcuate fasciculotomy (Youmans, pp. 2853-2862).

Answer 67

**A. Arcuate eminence ** B. Tegmen tympani C. Vestibule D. Vertical crest E. Vestibular prominence ## Footnote The superior semicircular canal projects into the floor of the middle cranial fossa as the arcuate eminence (Tew, pp. 48- 49; Wili(ins, pp. 1071-1073).

Answer 68

A. ~I'!icldle meningeal artery B. Trigeminal nerve (V3) C. Lesser superficial petrosal nerve **D. Hypoglossal nerve ** E. Greater superficial petrosal nerve ## Footnote Structures often visible on the middle fossa floor during subtemporal approach include the middle meningeal artery (often sacrificed by cautery and packing of the foramen spinosllm), trigeminal nerve (V3), lesser superficial petrosal nerve, greater superficial petrosal nerve, ICA (if there is a small dehiscence in the bone), as well as the arcuate eminence, which overlies the superior semicircular canal. Decreased tearing after surgery most likely resulted from injury of the greater superficial petrosal nerve, which provides parasympathetic supply to the lacrimal and nasal gland. Additional exposure to the posterior fossa during a sub temporal approach may be gained by removing the bone of I

Answer 69

A. Lesser petrosal nerve injury **B. Greater petrosal nerve injury ** C. Geniculate ganglion injury D. Chorda tympani injury E. Injury of Jacobson's nerve ## Footnote Structures often visible on the middle fossa floor during subtemporal approach include the middle meningeal artery (often sacrificed by cautery and packing of the foramen spinosllm), trigeminal nerve (V3), lesser superficial petrosal nerve, greater superficial petrosal nerve, ICA (if there is a small dehiscence in the bone), as well as the arcuate eminence, which overlies the superior semicircular canal. Decreased tearing after surgery most likely resulted from injury of the greater superficial petrosal nerve, which provides parasympathetic supply to the lacrimal and nasal gland. Additional exposure to the posterior fossa during a sub temporal approach may be gained by removing the bone of I

Answer 70

A. Further drilling of Glasscock's triangle **B. Additional exposure through Kawase's quadrilateral ** C. Further drilling of the arcuate eminence D. Identifying Trautmann's triangle and exposing medially to this landmark E. Modifying the approach by utilizing a presigmoid corridor ## Footnote Structures often visible on the middle fossa floor during subtemporal approach include the middle meningeal artery (often sacrificed by cautery and packing of the foramen spinosllm), trigeminal nerve (V3), lesser superficial petrosal nerve, greater superficial petrosal nerve, ICA (if there is a small dehiscence in the bone), as well as the arcuate eminence, which overlies the superior semicircular canal. Decreased tearing after surgery most likely resulted from injury of the greater superficial petrosal nerve, which provides parasympathetic supply to the lacrimal and nasal gland. Additional exposure to the posterior fossa during a sub temporal approach may be gained by removing the bone of I

Answer 71

**A. Herniation of the cerebellar tonsils through the foramen m agn um** B. Brainstem distortion C. Large hemispheric insult D. Hypoxia of the brainstem E. Posterior fossa mass ## Footnote The Cushing response consists of the triad of hypertension, bradycardia, and an irregular breathing pattern. According to many authors, the most likely mechanism accounting for this response is reduction in oxygenation in an area just rostral to the medulla. For this reason it is also called the ischemic response (Greenberg, p. 642; Committee on Education in Neurological Surgery, pp. 58, 155).

Answer 72

A. Hoarseness B. Dysphagia C. Unilateral tongue atrophy **D. Palpable neck mass ** E. Hypertension ## Footnote The most common clinical presentation of carotid body tUlUors is a palpable neck mass in the high cervical region. Less commonly patients present with hoarseness, dysphagia, and unilateral tongue atrophy and wealmess due to the tumors' proximity to the vagus and hypoglossal nerves. These tumors are generally benign, although they do tend to locally invade adjacent tissue, which can make their resection difficult. An evaluation of the endocrine system may be warranted, especially in patients with hypertension and tachycardia. Some patients may harbor a pheochromocytomalike lesion that secretes excess catecholamines. In such patients, a.-adrenergic blockade must be started about 2 weeks preoperatively to control hypertension, tachycardia, and the potential for arrhythmia. Preoperative planning is critical in these patients to reduce comorbidity. Some may require preoperative embolization to reduce the amount of bleeding during surgery (Youmans, pp. 1677-1681).

Answer 73

A. Diabetes insipidus **B. Pheochromocytoma ** C. I-Iyperprolactinemia D. Phenylketonuria E. None of the above ## Footnote The most common clinical presentation of carotid body tUlUors is a palpable neck mass in the high cervical region. Less commonly patients present with hoarseness, dysphagia, and unilateral tongue atrophy and wealmess due to the tumors' proximity to the vagus and hypoglossal nerves. These tumors are generally benign, although they do tend to locally invade adjacent tissue, which can make their resection difficult. An evaluation of the endocrine system may be warranted, especially in patients with hypertension and tachycardia. Some patients may harbor a pheochromocytomalike lesion that secretes excess catecholamines. In such patients, a.-adrenergic blockade must be started about 2 weeks preoperatively to control hypertension, tachycardia, and the potential for arrhythmia. Preoperative planning is critical in these patients to reduce comorbidity. Some may require preoperative embolization to reduce the amount of bleeding during surgery (Youmans, pp. 1677-1681).

Answer 74

A. Topectomy B. Limitedlesionectomy C. Motor cortex stimulation **D. Multiple subpial transections ** E. Vagal nerve stimulation ## Footnote Multiple subpial transection (MST) was developed as a procedure to address seizure activity that extends beyond the area of resection and into eloquent cortex. The cerebral cortex has functional vertical columns, with its vertical orientation of incoming and outgoing fibers. Seizures, however, are believed to spread horizontally through the cortex. MST involves disconnecting the vertical columns of the cerebral cortex, which inhibits synchronization and spread of the seizure focus with minimal injury to the cortex. The most common problem faced by patients after this procedure includes subtle, transient deficits corresponding to the area of resection that typically improve. Permanen t complication rates after this procedure are in the order of 5% (Youmans, pp. 2635-2642).

Answer 75

A. Facialnumbness B. Bradycardia **C. Dysphonia ** D. IIypotension E. Short-lived arrhythmia ## Footnote The most C0I111110n surgical complication after vagal nerve stimulator (VNS) placement is infection. Transient vocal cord paralysis with hoarseness and swallowing problems is the second 1110st C0111mon surgical complication of VNS. Temporary lower face numbness and wealmess occur in about 0.7% of patients, likely related to high cervical incisions and superficial nerve injury (Youmans, pp. 2649-2650).

Answer 76

**A. The lateral stability is significantly enhanced if the pedicle screw angle is 30 degrees or greater ** B. The use of transiL,ation increases the rotational but not the lateral load stability of the construct C. Without a transfixator, the vertebral column is stable in lateral load D. None of the above E. All of the above ## Footnote The internal stabilization of two adjacent segments of the lumbar spine with a pedicle screw construct having a pedicle-to-pedicle screw angle of zero and no transfi...xitor is not stable in lateral or rotational load, as each of the screws are free to turn in their screw holes in the body. Stability can be enhanced by the application of a transfi...xitor or angling the screws inward to form a pedicle-to-pedicle screw angle of 30 degrees (Carson, pp. 893- 901; Committee on Education in Neurological Surgery, pp. 36, 128).

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