Spine (Updated) Flashcards

Question

What are the radiographic parameters to assess for atlas fractures? [JAAOS 2014;22:718-729]

Answer 1

1. Atlanto-dens interval (ADI) * Distance between anterior dens and posterior aspect of anterior arch of C1 * Normal = \<3mm in adults * \>3mm indicates transverse ligament disruption and C1-C2 instability 2. Lateral atlanto-dens interval * Distance between the lateral surface of the dens and the medial surface of the lateral mass of C1 * Normal = \<2mm of asymmetry 3. Combined lateral mass overhang * Combined horizontal distance from lateral border of C1 to lateral border of C2 on open mouth radiographs or coronal CT * Normal = \<7mm * \>7mm indicates transverse ligament rupture and C1-C2 instability

Answer 2

Landells Classification * Type I - isolated anterior or posterior arch fracture * Type II - Jefferson burst fracture (bilateral anterior and posterior arch fractures) * Type III - unilateral lateral mass fracture

Answer 3

Dickman classification * Type I - intrasubstance tear * Type II - bony avulsion from tubercle at lateral mass of C1

Answer 4

Depends on the integrity of transverse ligament injury * If stable (ligament intact): * Based on ADI \<3, lateral ADI \<2mm of asymmetry, combined lateral mass overhang \<7mm * External immobilization (halo or hard cervical orthosis) * If unstable (ligament disrupted) * Posterior C1-C2 fusion * C1 lateral mass screw, C2 pars or pedicle * Occipitocervical fusion * If C1 lateral mass purchase inadequate due to comminution

Answer 5

1. Atlanto-dens interval * Normal \<3mm in adults (\<5mm in children) 2. Space available for the cord – SAC (posterior atlantodens interval – PADI) * Normal \>13mm

Answer 6

Type A * Rotationally displaced in the transverse plane (transverse ligament intact) * Often nontraumatic * Treatment – reduction and immobilization Type B * Translation between C1-C2 (Unstable) * Transverse ligament disrupted * Treatment: * Type I transverse ligament disruption = C1-C2 fusion * Type II transverse ligament bony avulsion = posterior C1-C2 fusion or halo immobilization following traction Type C * Distraction between C1-C2 (vertically unstable) * Similar to craniocervical dissociation and often associated with it * Treatment: * C1-C2 fusion * C0-C2 fusion if associated with craniocervical dissociation

Answer 7

1. Anderson and D’Alonzo Classification * Type I - odontoid tip fracture * Oblique fracture due to bony avulsion of the alar ligament * Type II - base of the dens fracture * Does not involve the C2 superior articular facet * High non-union rate due to watershed area * Type III – C2 body fracture * Does involve the C2 superior articular facet 2. Grauer modification * Type IIA - transverse fracture, \<1mm displacement * Type IIB- oblique fracture extending from anterosuperior to posteroinferior * Type IIC- oblique fracture extending from anteroinferior to posterosuperior * May be associated with significant anterior comminution

Answer 8

1. Type I * Stable fractures (at least one alar ligament and the transverse ligament is intact) * Cervical collar * Unstable fractures (associated craniocervical dissociation) * Posterior C0-C2 fusion 2. Type II * Young patient * No risk factors for nonunion = halo immobilization * Risk factors for nonunion = surgery * Elderly patient * Surgical candidate = surgical stabilization * Posterior C1-C2 fusion * Not surgical candidate = cervical orthosis * Results in fibrous union in most cases * Halo vest is associated with high rate of morbidity and mortality in elderly 3. Type III * Cervical orthosis

Answer 9

1. Age \>40 2. Posterior displacement \>5mm 3. Angulation \>11° 4. Comminution 5. Fracture gap \>1mm 6. Delay in treatment (4 day delay) 7. Concomitant neurological injury

Answer 10

1. Anterior fixation (odontoid screw) * Anatomic reduction and one or two partially threaded screws under biplanar fluoroscopy * Indications: * Grauer type IIb * Contraindications: * Osteoporosis, comminution, reverse obliquity (type IIc), short neck, barrel chest, nonunion 2. Posterior C1-C2 fusion * C1 lateral mass, C2 pars or pedicle * Indications: * Odontoid screw contraindicated

Answer 11

Levine and Edwards Classification * Type I * Minimally displaced pars interarticularis fracture * Translation \<3mm of C2, no angulation * MOI = axial load and hyperextension * Type Ia * Oblique fracture through one pars interarticularis and anterior to the pars within the body of the contralateral side (unstable) * Type II * Translation \>3mm of C2 * MOI – axial load and hyperextension followed by flexion * Type IIa * Angulation (kyphosis) more than translation * MOI = flexion-distraction * Type III * Similar pars fracture as type I plus C2/C3 facet dislocation * MOI = flexion distraction followed by hyperextension * \*\*\*Note: hyperextension causes the pars fracture and flexion causes PLL and disc rupture

Answer 12

Type I - hard cervical orthosis (12 weeks) Type Ia - halo immobilization Type II - halo immobilization (12 weeks) Type IIa * C2-C3 ACDF or posterior fixation [JAAOS 2014;22:718-729] * Reduction with gentle axial load + hyperextension, then compression halo immobilization for 6-12 weeks [Orthobullets] Type III - posterior reduction and stabilization * C2-C3 or C1-C3 fusion

Answer 13

1. Allen and Ferguson * 6 classes based on mechanism of injury and static radiographs (used in research) * Flexion-compression, vertical compression, flexion-distraction, extension-compression, extension-distraction, lateral flexion 2. Subaxial Injury Classification System (SLIC) * Three components * Morphology * Integrity of the discoligamentous complex * Neurological status * Score dictates treatment * \<4 = conservative treatment * 4 = treatment at discretion of surgeon * \>4 = surgical treatment

Answer 14

1. Compression fracture * Characteristics = anterior vertebral height loss, posterior vertebrae not involved * Nonoperative * Indicated if stable and PLC intact * Facet joints are not subluxed or dislocated * No vertebral translation * Minimal gapping of interspinous spaces * Kyphosis <11° * Rigid cervical collar for 3 months followed by flex-ex views * Operative * Indicated if unstable or neurological deficit * Facet joint subluxation or dislocation * Vertebral translation * Gapping of interspinous spaces * Kyphosis >11° * MRI findings suggestive of PLC disruption * Anterior or posterior stabilization 2. Burst fracture * Characteristics = comminuted vertebral body fracture involves the posterior vertebral body often with retropulsed fragments * Nonoperative: * Indicated if no PLC disruption, no neurological deficit (rare) * Halo vest or rigid cervicothoracic orthosis * Operative: * Indicated if PLC disruption, neurological deficit * Anterior corpectomy * Plus posterior instrumentation and fusion if PLC is disrupted 3. Flexion teardrop fracture * Characteristics = oblique fracture line from anterior vertebral body to the inferior endplate (quadrangular fragment) * May have posterior translation of the posterior vertebral body * PLC disruption suggested by interspinous and facet gapping * Nonoperative * Minimally displaced, little kyphosis, intact PLC * Rigid cervical collar * Operative * Neurological deficit, PLC disruption * Posterior VB translation, kyphosis \>11° * ACDF 4. Extension teardrop fracture * Characteristics = small avulsion from anterior vertebral body * Nonoperative * Considered a stable injury * Rigid cervical collar

Answer 15

1. Facet subluxation 2. Unilateral facet dislocation (25% displacement on XR) 3. Bilateral facet dislocation (50% displacement on XR) 4. Complete dislocation (100% displacement on XR)

Answer 16

Unilateral vs. bilateral = 56% vs. 82.5%

Answer 17

1. Presence of a disc herniation can lead to neurological injury upon reduction/realignment of the cervical spine 2. Herniations with disc material posterior to the displaced vertebral body are most concerning

Answer 18

1. Bilateral facet dislocations = complete disruption of PLC and facet capsules 2. Unilateral facet dislocations = PLC may be intact

Answer 19

1. “Reverse Hamburger Bun Sign” (normal = “Hamburger bun sign”) 2. “Naked facet sign”

Answer 20

1. Obtain MRI * Neurologically intact patient * No urgency to perform reduction, if disc is present you can convert a neurologically intact patient to one with deficits if reduction performed * Obtunded, nonexaminable patient * If neurologically intact, reduction in presence of disc may lead to neurological deficit * Planning posterior approach and reduction * Failed closed reduction or neurological deterioration during closed reduction [Orthobullets] 2. Omit MRI * Awake, alert, cooperative patient with incomplete cord injury or worsening neurological deficit * Patient would benefit from immediate reduction rather than delaying for MRI * Complete cord injury

Answer 21

1. Requires an awake, alert and cooperative patient 2. Gardner-Wells tongs are applied * Pins 1cm above the pinna of the ear in line with the external auditory meatus below the equator of the skull * Placement slightly posterior produces flexion moment (often desirable in cervical facet dislocation) * Skin is prepped and lidocaine injected subcutaneously and subperiosteally * Pins are tightened until indicator pin protrudes at least 1mm 3. 10lbs of weight is applied initially then 5-10lbs added incrementally * After each weight – lateral radiograph and neurological examination * Apply additional weight after 10-15mins 4. Once reduction is achieved the weight can be reduced to approximately 10-20lbs to maintain reduction

Answer 22

1. Advantages * Removes disc (whether herniated or not) prior to reduction * Muscle-sparing approach * May eliminate need for posterior approach and stabilization * Fuses single motion segment (posterior approach may require more levels) 2. Disadvantages * Reduction more difficult * Failure to reduce requires a posterior approach (and possible returning to anterior for fixation)

Answer 23

1. Caspar pins 2. Laminar spreader 3. Cobb

Answer 24

1. Towel clip grasping the spinous process 2. Penfield 4 elevator over superior articular process of lower vertebra to lever up the inferior articular process of the upper vertebra 3. Resect tip of superior articular process of lower vertebra

Answer 25

1. Presence of disc herniation 2. Absence of disc herniation (if surgeon prefers over posterior)

Answer 26

Absence of disc herniation

Answer 27

1. Highly unstable bilateral facet dislocations 2. Presence of facet gap or kyphosis following anterior surgery 3. Delayed presentation with fixed deformity

Answer 28

1. synchondroses between ossification centers 1. neurocentral synchondroses - between posterior elements and body 2. dentocentral synchondroses - between dens and body of C2 3. normal = smooth with subchondral sclerotic lines 2. increased elasticity of ligaments, capsule and enplates 3. wedge-shaped vertebral bodies 1. normal = ≤ 3mm of anterior wedging 4. horizontally oriented facet joints 5. virtually absent uncinate processes 6. pseudosubluxation of C2 and C3 1. normal = spinolaminar line (swichuk’s line) between C1-3 should pass within 1mm of C2 spinolaminar junction 2. abnormal = >1.5mm of displacement 7. loss of cervical lordosis in neutral position 8. increased ADI 1. normal = 3-5mm Note - pediatric spine adops a more adult configuration by age 8

Answer 29

- goal is to immobilize the cervical spine in a neutral position - problems - rigid collars often do not fit children properly - improper cervical collar pay potentiate atlanto-occipital distraction and worsen neurological injury - children’s heads are proportionally larger conpared to body size - immobilization on a standard spinal board will induce the head and neck into flexion - recommendations for pediatric spinal immobilization - initially, allow the child to find a comfortable position while maintaing manual in-line stabilization - if properly sized collar can be safely fitted then apply it - if collar is not properly sized then maintain a neutral or comfortable position with blocks/rolled up towels placed on either side of the head and tape to secure them in place - utilize an occipital recess or thoracic elevation to accomodate the child’s proportionally larger head

Answer 30

- sciwora = spinal cord injury without radiographic abnormality - refers to ‘objective signs of myelopathy resulting from trauma with no evidence of ligamentous injury or fractures on plain radiographs or CT - occurs as a result of greater elasticity of spinal structures in pediatric population - more common in younger children but may occur at the age of 16 - traditionally treated by external immobilization for up to 3 months to allow tissues to heal - at 3 months a flexion-extension radiograph is performed to ensure no instability

Answer 31

1. Anterior column = anterior half/part of vertebral body/disc and ALL 2. Middle column = posterior half/part of vertebral body/disc and PLL 3. Posterior column = posterior elements including pedicles, facets, lamina, spinous process and ligaments \*\*\*NOTE – based on this system fractures extending into the middle column are largely considered unstable

Answer 32

* Supraspinous lig * Interspinous lig * Ligamentum flavum * Facet joint capsules

Answer 33

1. AP view = widened interpedicular distance 2. Lateral view = loss of height of posterior cortex

Answer 34

1. Thoracolumbar Injury Classification and Severity Score (TLICS) * 3 injury characteristics * Injury morphology * Neurological status * Integrity of PLC * Score dictates treatment * \<4 = nonsurgical * 4 = nonsurgical or surgical * \>4 = surgical 2. AO Thoracolumbar Classification (Morphology) * TYPE A = Compression Injuries * A0 = Minor, nonstructural fractures * Fractures which do not compromise the structural integrity of the spinal column (eg. transverse process and spinous processes) * A1 = Wedge-compression * Fracture of a single endplate without involvement of the posterior wall of the vertebral body * A2 = Split * Fracture of both endplates without involvement of the posterior wall of the vertebral body * A3 = Incomplete burst * Fracture with any involvement of the posterior wall; only a single endplate fractured * Vertical fracture of the lamina is usually present and does not constitute a tension band failure * A4 = Complete burst * Fracture with any involvement of the posterior wall and both endplates * Vertical fracture of the lamina is usually present and does not constitute a tension band failure * TYPE B = Distraction Injuries * B1 = Transosseous tension band disruption (Chance fracture) * Monosegmental pure osseous failure of the posterior tension band * B2 = Posterior tension band disruption * Bony and/or ligamentary failure of the posterior tension band together with a Type A fracture * Type A fracture should be classified separately * B3 = Hyperextension * Injury through the disc or vertebral body leading to hyperextended position of the spinal column * Commonly seen in ankylotic disorders * Anterior structures, especially ALL are ruptured but there is a posterior hinge preventing further displacement * TYPE C = Translation Injuries * C = Displacement/dislocation * There are no subtypes because various configurations are possible due to dissociation/dislocation * Can be combined with subtypes of A or B

Answer 35

1. Neurologically intact 2. <25° kyphosis 3. <50% vertebral height loss 4. <50% canal compromise 5. Intact PLC

Answer 36

Hyperextension thoracolumbar orthosis (eg. Jewett) or casting for 3 months

Answer 37

1. Posterior instrumentation and fusion * 2 levels above and 2 levels below affected level * Don’t end at junction 2. Decompression if neurological compromise

Answer 38

Short segment posterior instrumentation and fusion if anterior column intact

Answer 39

1. Indirect decompression through ligamentotaxis 2. Direct decompression * Laminectomy, retraction of thecal sac and direct decompression of bone fragments (tamps to push fragments back into vertebral body) * Only below level of conus * Transpedicular decompression * Can be performed at T1-L5 without risk from retraction to thecal sac * Superior and inferior laminotomy followed by burring and thinning of the medial pedicle to allow access to tamp fragments back into vertebral body

Answer 40

1. “Soft Disc” herniations * Nuclear material from acute disc 2. “Hard Disc” herniations * Secondary to degenerative disc disease with annular bulging without frank herniation or uncovertebral osteophytes 3. Disc height loss leading to foraminal height loss 4. Facet joint hypertrophy 5. Inflammatory cytokines from disc herniation

Answer 41

1. Cervical nerve roots exit above their numbered pedicles * Except C8 which exits above T1 2. Exiting nerve roots affected * Eg. C5-C6 disc herniation affects the C6 nerve root

Answer 42

1. Unilateral neck pain 2. Upper trapezial and interscapular pain 3. Radiculopathy patterns/Symptoms * C2 * Posterior occipital headaches, temporal pain * C3 * Occipital headache, retro-orbital or retroauricular pain * C4 * Base of neck, trapezial pain * C5 * Lateral arm pain * Motor loss - Deltoid * Reflex - Biceps * C6 * Radial forearm pain, pain in the thumb and index fingers * Motor loss - Biceps, wrist extension * Reflex - Brachioradialis * C7 * Middle finger pain * Motor loss - Triceps, wrist flexion * Reflex - Triceps * C8 * Pain in the ring and little fingers * Motor loss - Finger flexors * T1 * Ulnar forearm pain * Motor loss - Hand intrinsics

Answer 43

1. Spurling’s test 2. Shoulder abduction test (Bakody’s test) * For C4-6 impingement * Patient puts hand on head, relief of symptoms is positive test

Answer 44

1. Nonoperative – First Line * 75% of patients improve without surgery * Nonoperative modalities may not alter natural history * Options include brief immobilization, home traction, medications, PT, manipulations, steroid injections 2. Operative * Indications: * Severe or progressive neurological deficit * Significant pain that fails to respond to nonoperative treatment

Answer 45

1. Anterior cervical discectomy and fusion\* * Advantages * Direct removal of anterior pathology without neural retraction * Anterior bone graft restores height and provides indirect decompression of neural foramens * Fusion may improve associated neck pain * Fusion prevents recurrent neural compression * Low rates of infection and wound complications * Muscle-sparing approach * Disadvantages * Pseudoarthrosis * Plate complications * Adjacent joint disease * Speech and swallowing difficulties * Autograft harvest morbidity if used 2. Posterior laminoforaminotomy * Advantages * Avoids fusion and related complications * Can be done with minimally invasive techniques * Minimal morbidity * Disadvantages * Possible incomplete decompression * Inability to restore disc and foramen height * Progressive degeneration in absence of fusion (recurrence of symptoms) * Removal of anterior pathology would require neural retraction

Answer 46

Often stepwise deterioration with periods of stability, can be progressive neurological decline

Answer 47

1. Inherited predisposition 2. Congenital stenosis

Answer 48

1. Degenerative disc (anterior) 2. Uncovertebral joint osteophyte (anterior) 3. Hypertrophied/infolded ligamentum flavum (posterior) 4. Facet joint degeneration (posterior)

Answer 49

1. Axial neck pain and decreased ROM 2. Gait instability/balance impairment * Diminished proprioception due to dysfunction of posterior column 3. Diminished hand dexterity/difficulty with fine motor tasks 4. Bowel/bladder dysfunction (advanced CSM) 5. Inability to ambulate (advanced CSM)

Answer 50

1. Gait 2. Heel-toe walking 3. Romberg test 4. Finger escape sign * Ulnar two digits drift into abduction with fingers in extension for \>1 minute 5. Grip-and-release test * Normal = 25-30 in 15 sec 6. Long tract signs * Babinski * Hoffmann * Inverted radial reflex * BR reflex elicits flexion of the long finger flexors * Hyperreflexia * Sustained clonus \>3 beats 7. Lower motor neuron signs * Hyporeflexia 8. Sensory deficits may be present in UE and LE

Answer 51

1. Radiographs * Torg-Pavlov ratio = AP width of spinal canal/AP width of vertebral body * Stenosis = <0.80 * Categorize the alignment * Lordotic, neutral, kyphotic, sigmoid 2. MRI * Myelography effect * T2 images should demonstrate fluid both anterior and posterior to the cord * Effacement of CSF * Cross sectional cord deformation * Oval or kidney bean in severe stenosis * Signal change within the cord * Poor prognosis = high signal on T2 (myelomalacia) and low signal on T1 * Compression ratio [Orthobullets] * Smallest AP diameter of cord/largest diameter of cord (at a single level) * Poor prognosis = \<0.4 * Modified K-line * Line connecting the midpoints of the spinal cord between C2 and C7 * Helps predict if adequate posterior drift back will be achieved from anterior sites of compression * Measure the minimum interval distance between the line and anterior compressive factors. * >4mm of space related with an optimal neurological recovery in non-lordotic patients after laminoplasty 3. CT * Assess for spondylotic bars, OPLL, disc osteophyte complex 4. CT myeolography * Blockage of flow of contrast indicates regions of compression

Answer 52

20-60% of patients with mild CSM progress over time in absence of surgery

Answer 53

Prevent progression of neurological dysfunction

Answer 54

1. Intraoperative pause 2. Communicate with anaesthesiologist, surgeon, neuromonitoring team 3. Check equipment 4. Ensure blood pressure is adequate (MAP \>80mmHg recommended) 5. Ensure oxygen saturation is adequate 6. XR to check hardware placement 7. Reverse surgical interventions until baseline achieved 8. If alert persists perform wake-up test

Answer 55

1. Anterior * Traditionally, preferred for 1 or 2 segment pathology * Regional kyphosis >13° is an indication for anterior * Anterior procedures include: * ACDF * Anterior subtotal vertebrectomy * Anterior cervical corpectomy 2. Posterior * Traditionally, preferred for >2 segment pathology * Posterior procedures include: * Laminectomy alone * Laminectomy and fusion * Laminoplasty (open door or French door) 3. Combined

Answer 56

1. >10° rigid kyphosis * 1 or 2 levels of compression = anterior approach * ACDF/Corpectomy * 3+ levels of compression = combined anterior and posterior * Anterior corrects kyphosis and decompresses * Posterior decompresses 2. <10° rigid kyphosis * 1 or 2 levels of compression = anterior approach * ACDF/Corpectomy * 3+ levels of compression = posterior approach * Laminectomy + fusion OR laminoplasty

Answer 57

C5 palsy (4.6% of patients) * Thought to be due to posterior migration of the spinal cord with tethering of the nerve root

Answer 58

Replacement of the PLL with lamellar bone

Answer 59

1. East Asians 2. Male 3. DISH 4. Hyperparathyroidism 5. Hypophosphatemic rickets 6. Hyperinsulinemia 7. Obesity

Answer 60

Cervical myelopathy

Answer 61

1. >60% spinal canal stenosis (occupancy ratio) 2. ≤6mm SAC 3. Increased cervical ROM 4. OPLL that is laterally deviated in the spinal canal

Answer 62

1. Radiographs 2. CT 3. MRI

Answer 63

1. Solitary – one vertebral level or space 2. Segmental – multiple separate lesions 3. Continuous – single lesion involving multiple interspaces 4. Mixed – combines features of the other 3

Answer 64

1. Line from center of the spinal canal at C2 to center of canal at C7 2. Assesses the affect of the size of OPLL and the cervical lordosis 3. Negative K-line = OPLL protrudes posterior to the K-line 4. Positive K-line = OPLL protrudes anterior to the K-line 5. Significance = negative K-line is a negative predictor of outcome for posterior surgery alone

Answer 65

1. Better detects OPLL 2. Allows assessment of the occupancy ratio and location of the OPLL (central vs. lateral) 3. Detects dural ossification * Appears as “double layer sign” * If present \>50% dural tear rates with anterior decompression

Answer 66

Assesses the cord compression and condition of the cord \*\*\*Note – OPLL appears as hypointense on T1 and T2

Answer 67

No symptoms of myelopathy

Answer 68

Myelopathy

Answer 69

1. Anterior decompression and fusion * Advantages * Direct decompression, most effective for severe disease (\>60% canal occupancy) * Disadvantages * Technically demanding * Higher complication rate * Cannot decompress above C2 2. Laminectomy and fusion * Advantages * Allows decompression of entire cervical spine * Low complication rate * Low risk of kyphotic progression * Disadvantages * Indirect decompression * Risk of OPLL progression * Poor results for severe compression * Risk of C5 palsy higher than anterior approach 3. Laminoplasty * Advantages * Allows decompression of entire cervical spine * Lowest immediate complication rate * Motion preserving * Disadvantages * Similar to laminectomy and fusion but with higher rates of disease progression * Contraindicated with loss of lordosis

Answer 70

1. OPLL occupies >60% of the canal 2. Loss of cervical lordosis

Answer 71

Lumbar spinal stenosis

Answer 72

1. Acquired * Secondary to degeneration (spondylosis) – most common * Degenerative disc disease * Loss of disc height * Bulging of the anulus fibrosis * Facet arthropathy * Loss of disc height transfers load posteriorly resulting in facet joint hypertrophy, osteophyte formation * Ligamentum flavum hypertrophy and buckling * Others: * Post surgery * Trauma * Inflammatory * Neoplastic 2. Congenital

Answer 73

Achondroplasia * Congenitally short pedicles * Thick lamina * Interpedicular distance that decreases caudally

Answer 74

1. Central * Disc-osteophyte complex and ligamentum flavum hypetrophy 2. Lateral recess * Facet hypertrophy and osteophytes 3. Foraminal * Loss of disc height * Foraminal disc protrusion * Osteophyte * Scoliosis 4. Extraforaminal * Far lateral disc herniation

Answer 75

Sagittal T1 * Often defined as foraminal diameter <3mm or foraminal height <15mm

Answer 76

1. Central stenosis * Neurogenic claudication * Pain in low back, buttocks and/or posterior thighs * Worse with standing and better with sitting or leaning forward * Worse with walking, not relieved when standing still * Better with activities in flexed position (bicycling, pushing shopping cart) 2. Lateral stenosis * Radicular symptoms

Answer 77

Usually normal

Answer 78

1. Nonsurgical – first line * Tylenol, NSAIDs, PT, steroid injections 2. Surgical – failure of nonoperative * Pedicle to pedicle decompression * Pedicle to pedicle decompression and instrumented fusion * Indicated in presence of instability * Spondylolisthesis * Scoliosis * Iatrogenic * Created by complete laminectomy and/or removal of \> 50% of facets

Answer 79

Up to 95% at L4-L5 and L5-S1

Answer 80

1. Central * Causes back pain * Can cause cauda equina 2. Paracentral (posterolateral) * Affects the descending nerve root (L4/5 affects L5) 3. Foraminal (far lateral) * Affects the exiting nerve root (L4/5 affects L4)

Answer 81

1. Protrusion * Eccentric bulging through an intact anulus fibrosus 2. Extrusion * Disc material crosses the disrupted anulus fibrosus but is continuous with the disc space 3. Sequestered * Free fragment * Disc material is not continuous with the disc space

Answer 82

1. Sclerotomal pain (mesodermal) * Low back, buttock, posterior thigh pain 2. Radicular pain * Leg pain in dermatomal distribution * Worse with Valsalva 3. Cauda equina

Answer 83

1. Weakness 2. Hyporeflexia 3. Positive SLR (sensitive not specific) 4. Contralateral SLR (more specific, less sensitive) 5. Femoral nerve stretch (L1-L4 nerve root involvement)

Answer 84

1. Loss of lordosis (spasm) 2. Loss of disc height 3. Vacuum phenomenon * Collection of gas in the disc space

Answer 85

In the general population, \>90% improve within 6 weeks with nonsurgical treatment \*\*\*Note: nonsurgical management does not change the natural history but provides symptomatic relief

Answer 86

Failure of a 6 week course of nonoperative treatment

Answer 87

Laminotomy with discectomy (microdiscectomy)

Answer 88

Wiltse approach * Interval – multifidus and longissimus

Answer 89

* Leg pain is chief complaint * Positive SLR * Weakness correlates with MRI findings * Married status

Answer 90

1. Recurrent disc 2. Instability 3. Degenerative disc disease

Answer 91

1. Dysplastic (congenital) * Dysplasia of the upper sacrum or neural arch (the pars is normal) 2. Isthmic * A. Lytic – fatigue fracture of the pars * B. Elongated but intact pars (due to repeated micro fractures and healing) * C. Acute fracture of the pars 3. Degenerative 4. Traumatic (fracture other than the pars) 5. Pathologic 6. Iatrogenic

Answer 92

Facet arthrosis

Answer 93

1. Sagittally oriented facets (congenital) 2. Transitional lumbosacral L5 /sacralization of L5

Answer 94

1. Females 2. \>40 3. African americans 4. Diabetics

Answer 95

1.Central and lateral recess stenosis * A. Caused by slippage, hypertrophied ligamentum flavum, facet arthrosis * B. Affects descending L5 nerve root 2.Foraminal stenosis * A. Caused by * i. Vertical stenosis – due to loss of disc height and posterolateral osteophytes from vertebral body compressing nerve root against inferior pedicle * ii. Anterosuperior stenosis – due to facet arthrosis and posterior vertebral body osteophytes * B. Affects exiting L4 nerve root

Answer 96

1. Mechanical back pain (most common) * Relieved with rest 2. Neurogenic claudication and leg pain (second most common) * Same as lumbar spinal stenosis

Answer 97

1. Often normal 2. Hamstring tightness 3. Painful lumbar ROM

Answer 98

1. Nonoperative – first line 2. Surgery * Posterior decompression and posterolateral fusion (+/- instrumentation)

Answer 99

1. Strong * Recommend against vertebroplasty 2. Moderate * Recommend calcitonin for 4 weeks in patients who present with acute compression fractures (0-5 days of onset of symptoms) and are neurologically intact 3. Limited * Kyphoplasty is an option for symptomatic compression fractures * L2 nerve block for symptomatic L3 or L4 compression fractures * Ibandronate and strontium ranelate are options to prevent additional symptomatic fractures

Answer 100

1. Prevention of osteoporosis is the most important principle in the management of the condition. 2. Prompt referral to an endocrinologist for preoperative optimization is recommended. 3. Longer fusion constructs and avoiding constructs that start or end at the cervicothoracic or thoracolumbar junction may protect against junctional or segmental failure 4. At least three fixation points above and below the apex of the deformity should be used 5. Hybrid constructs (pedicle screws, hooks, wires) may improve fixation strength 6. Iliac and/or sacral fixation in long fusion constructs is recommended, when feasible, to maximize stability 7. Anterior column support increases load-sharing, decreases strain on constructs, and should be used whenever possible 8. The direction of pedicle screw insertion affects pullout strength, and purchase in subchondral bone (eg, sacral promontory) is recommended to maximize fixation 9. Undertapping increases the insertional torque and pullout strength of pedicle screws 10. Hubbing of pedicle screws adversely affects pullout strength and should be avoided.

Answer 101

Indications * Painful osteoporotic compression fracture that does not improve with 2 to 3 weeks of nonsurgical care * Patient hospitalized as a result of painful osteoporotic fracture * Painful pathologic fracture * Aggressive hemangioma of the spine * Kümmell disease * Post traumatic AVN of vertebral body Absolute Contraindications * Asymptomatic fractures * History of vertebral body osteomyelitis * Allergy to bone fillers or opacification agents * Irreversible coagulopathy Relative Contraindications * Presence of radiculopathy * Bone retropulsion against neural structures * Greater than 70% collapse of vertebral body height * Multiple pathologic fractures * Lack of surgical backup to manage potential complications

Answer 102

1. Cement extravasation 2. Embolization 3. New fracture * Due to increased stiffness leading to higher loads on adjacent segments

Answer 103

1. Failed medical management 2. Need for open culture/biopsy 3. Spinal instability 4. Neurological deficit or deterioration

Answer 104

1. Advanced age 2. Malnutrition 3. Immunocompromised 4. Diabetes 5. IVDU 6. HIV/AIDS 7. Malignancy 8. Chronic steroid use 9. Renal failure 10. Septicemia 11. Spinal surgery 12. Intravascular devices 13. Presence of foreign bodies

Answer 105

Staph aureus

Answer 106

Lumbar spine

Answer 107

1. Epidural, paravertebral or psoas abscess 2. Mediastinum, supraclavicular fossa and retropharyngeal space in cervical osteomyelitis

Answer 108

1. Insidious neck or back pain 2. Neurological deficits (30%) 3. Fever, weightloss, nausea/vomiting, anorexia, lethargy, confusion 4. Dysphagia

Answer 109

1. CBC 2. ESR/CRP 3. Blood culture 4. CT guided or open biopsy (if blood culture negative) * Send samples for aerobic, anaerobic, fungal and acid fast bacilli cultures 5. Transesophageal echo (assess for bacterial endocarditis) 6. TB skin test if risk factors present 7. Radiographs * Assess for osteolysis, endplate destruction, vertebral collapse 8. MRI * **Imaging modality of choice** * Hyperintense signal on T2 and hypointense signal on T1 (disc and adjacent VB)

Answer 110

1. Pyogenic vertebral osteomyelitis * Medical management * 6-8 weeks of antibiotics and bracing * Duration of antibiotics should be increased in presence of abscess * Biopsy or blood culture should be sent prior to administration of antibiotics * If patient is septic empiric antibiotics can be started * Surgery * If fusion required autograft is preferred (over titanium cages or allograft) unless large defect 2. Discitis * Medical management * Mainstay of treatment * Surgery (rare) 3. Epidural abscess * Medical management * Antibiotics * Surgery * Absolute indication = progressive neurological deficit

Answer 111

1. Mycobacterium tuberculosis 2. Others * Brucellosis (second most common) * Actinomyces * Nocardia * Fungal (candidiasis, asperigillosis, coccidioidomycosis, blastomycosis, and cryptococcosis) * Parasitic (Echinococcus and Taenia solium)

Answer 112

1. Hematogenous from a pulmonary source * Most commonly 2. Contiguous spread from visceral sources

Answer 113

Thoracic spine

Answer 114

Caseating granuloma

Answer 115

1. Peridiscal (most common) * Begins adjacent to a single vertebral end plate (metaphysis) * Spreads peripherally to the adjacent intervertebral disc * Less severely affected and relatively preserved * Tracks deep to the ALL to spread to an adjacent vertebra 2. Central * Abscess formation in the central vertebral body * Leads to vertebral collapse and spinal deformity 3. Anterior * Begins anterior to the vertebral body and posterior to the ALL * Spreads under ALL, scallops vertebral body and may extend multiple levels

Answer 116

1. Immunocompromised (AIDS, organ transplant) 2. Travel to Asia, Africa, South America 3. Homeless 4. Known exposure (hospital, nursing, homeless shelter employee)

Answer 117

1. Back pain * Less severe and more insidious than pyogenic infection 2. Malaise, night sweats, weight loss, fevers 3. Kyphotic or gibbus deformity 4. Cutaneous sinuses 5. Neurologic deficits

Answer 118

1. Nonspecific – WBC, ESR, CRP 2. Tuberculin skin test * Positive = induration >5-15mm after 48-72 hours 3. Interferon gamma release assay * Blood test equally sensitive but more specific 4. PCR 5. CXR * Segmental or lobar infiltrates with ipsilateral hilar or mediastinal lymphadenopathy 6. Thoracolumbar xray * Osteolysis of affected vertebra * Kyphotic deformity (late) 7. MRI * T1 - Homogenous low signal with subligamentous spread * T2 – Heterogenous high signal with subligamentous spread 8. CT guided biopsy * Diagnostic yield = 42-76% * If nondiagnostic consider open biopsy * Send biopsy for: * Aerobic, anaerobic and tuberculous-specific culture (broth cultures) * Acid-fast bacilli smear microscopy * PCR * Pathology (detects caseating granuloma)

Answer 119

1. Separation of facet joints 2. Retropulsion 3. Lateral translation 4. Toppling * Identified when a line drawn along the anterior surface of the normal caudal vertebra intersects above the middle of the anterior wall of the cranial vertebral body

Answer 120

1. No neurology 2. No spinal instability

Answer 121

Pharmacological * RIPE – rifampin, isoniazid, ethambutol, pyrazinamide * Duration – 6-18 months * Serial clinical and radiographic evaluations

Answer 122

1. Failure of medical management 2. Neurological deficits 3. Spinal instability or deformity

Answer 123

1. Decompression * When anterior column is involved a direct resection is required 2. Excision of the pathological lesion * Debridement of all purulent material, granulation tissue, caseous tissue, sequestered bone and bone that is compressing neural elements 3. Reconstruction and stabilization of the spine * Following decompression and debridement structural graft is recommended for stability and correction of kyphotic deformity * Options include: * Structural autograft (iliac crest, rib) * Structural allograft (fibula) * Titanium cages with autogenous or allograft cancellous bone * Posterior instrumentation and fusion often added * Options [Orthobullets] * Single-stage transpedicular * Two-stage anterior decompression with bone grafting and posterior kyphosis correction and instrumentation 4. Continue pharmacological

Answer 124

1. Anterior approach 2. Radical debridement and decompression 3. Correction of the kyphotic deformity with uninstrumented structural allograft

Answer 125

1. Atlantoaxial impaction (65% of RA patients) * AKA Basilar invagination, cranial settling, superior migration of the odontoid 2. Atlantoaxial instability (4-35%) 3. Subaxial instability (7-29%)

Answer 126

Atlantoaxial instability → atlantoaxial impaction → subaxial instability

Answer 127

1. Atlantoaxial impaction * Collapse of the lateral masses due to involvement of the atlanto-occipital and atlantoaxial joints * Erosion of O-C1 and C1-2 joints such that odontoid appears to enter foramen magnum * Weakening and collapse of the lateral masses 2. Atlantoaxial instability * Due to weakening or rupture of the transverse, alar and apical ligaments * Synovitis and pannus weaken the transverse, alar and apical ligaments * Repetitive strain leads to stretching or rupture * Bony erosion of dens or atraumatic dens fractures possible 3. Subaxial instability * Due to destabilization of the facet joints with weakening of the facet capsule and interspinous ligaments * Destruction of facet joints and uncovertebral joints * Weakening of interspinous ligaments * Lack of osteophyte formation results in relative instability * Versus stability in OA due to osteophytes * Disc and annulus also degenerative but synovitis does not develop * Thus, anterior disease does not directly contribute to instability

Answer 128

1. Neck pain (most common - 40-80%) 2. Atlantoaxial impaction * Cervical myelopathy * C1+C2 nerve compression (occipitocervical pain) * Compression of the medulla oblongata * Sleep apnea * Sudden death * Compression of vertebral or anterior spinal arteries * TIAs, vertebrobasilar insufficiency or neurological deficits 3. Atlantoaxial instability * Clunking sensation with extension or sensation of head sliding forward with flexion * Cervical myelopathy * L’hermittes sign 4. Subaxial instability * Cervical myelopathy

Answer 129

Ranawat Classification * Grade I - normal * Grade II - Weakness, hyperreflexia, altered sensation * Grade IIIA - Paresis and long-tract signs, ambulatory * Grade IIIB - quadriparesis, nonambulatory

Answer 130

Prior to IIIB * I.e. While still ambulatory

Answer 131

* Male * RF positive * Higher initial CRP * Subcutaneous nodules * Advanced peripheral joint disease (rapid loss of carpal height)

Answer 132

1. Prolonged cervical spine symptoms \>6 months 2. Neurological signs or symptoms 3. Scheduled procedures requiring endotracheal intubation in patients who have not had cervical radiographs in 2-3 years 4. Rapidly progressive carpal or tarsal bone destruction 5. Rapid overall functional deterioration

Answer 133

1. Atlantoaxial impaction * McCrae’s line * Line between basion and opisthion * Normal = tip of dens should be below line * McGregor’s line * Line between hard palate and base of the occiput * Abnormal = tip of dens 4.5mm above line * Ranawat Index * Distance from midpoint of C2 pedicle along centre of odontoid to horizontal line through C1 * Abnormal = \<15mm in males, \<13mm in females * Cervicomedullary angle (MRI) * Angle between anterior aspect of cervical cord and anterior medulla * \<135° indicates impending neurological impairment * Clark’s station * C2 divided into thirds (1 is superior, 3 is inferior) * Abnormal = anterior ring of C1 is in the 2nd or 3rd station * Simplest method to use as the relationship does not change in flexion, extension or neutral * \*\*\*McRae and McGregors inaccurate with odontoid erosion 2. Atlantoaxial instability * ADI (atlantodental interval) * Distance between the anterior dens and the posterior anterior arch of C1 * Abnormal = \>3.5mm * \>5mm suggests instability * \>10mm suggests complete loss of ligamentous integrity * PADI/SAC * Posterior atlantodental interval/space available for the cord * Distance between the posterior dens and the posterior arch of C1 * Abnormal = ≤14mm is an indication for surgery * Need 14mm for canal (10 cord, 1 dura, 1 CSF) * \<10mm assoc with poor neuro outcomes * ≥14mm assoc with excellent neuro outcomes * Better predictor of neuro outcomes than ADI * \*\*\*ADI and PADI can not evaluate cord compression by soft tissues (i.e. pannus) 3. Subaxial instability * C2/3 and C4/5 most commonly involved * Kyphosis * “staircase” when multiple levels involved * Facet joint erosions and widening * Spindling of the spinous processes * Subluxation * Abnormal = \>4mm or 20% listhesis of vertebral body diameter

Answer 134

1. Intractable pain 2. Neurologic deficits 3. ADI \>10 [Orthobullets] 4. PADI ≤14mm 5. Dens migration ≥5mm rostral to McGregor’s line 6. Subaxial subluxation with canal diameter ≤14mm 7. Cervicomedullary angle \<135° \*\*\*Increased function and lifespan compared to non-op

Answer 135

1. In general, identify which of the 3 instability patterns are present then address each one 2. Atlantoaxial instability * Gallie or Brooks wiring * Contraindicated if subluxation cannot be reduced * Magerl transarticular C1-C2 screws (95% fusion rate) * Harms C1/2 lateral mass screws 3. Atlantoaxial instability with nonreducible subluxation * C1/2 stabilization (transarticular screws) with C1 decompression with posterior arch removal 4. Atlantoaxial impaction * Preop halo traction to reduce impaction * Occipitocervical fusion (occiput to at least C2) 5. Atlantoaxial impaction with failure of preoperative traction * Occipitocervical fusion with transoral resection of the odontoid or C1 posterior arch removal 6. Subaxial instability * If reducible, may be fused anteriorly or posteriorly * Posterior instrumentation and fusion * Extend fusion to the lowest involved level (do not stop at C7) * If nonreducible: * Anterior decompression/fusion is preferred * Posterior fusion if doing laminectomy

Answer 136

1. Flowing ossification along the anterolateral aspect of at least 4 contiguous vertebra 2. Preservation of disc height and relative absence of degenerative changes 3. Absence of facet joint or SI joint ankylosis

Answer 137

Thoracic spine (right sided due to aorta)

Answer 138

1. Cervical involvement * Dysphagia, hoarseness, sleep apnea, difficult intubation * OPLL and myelopathy 2. Lumbar involvement * Lumbar stenosis due to ligamentum flavum ossification and posterior element hyperostosis 3. Spine fracture and instability * Similar to AS, prone to spine fractures due to stiffness and long lever arms * Often follow low energy trauma, result in unstable fractures 4. Enthesophytes 5. Increased risk of HO following THA

Answer 139

1. bilatearl symmetric sacroiliitis 1. initial widening, progressive sclerosis to eventual fusion 2. marginal syndesmophytes development 1. shiny corner sign (sclerosis of the annulus fibrosus insertion into the endplate) 2. romanus lesion (erosion of the annulus fibrosus insertion into the endplate) 3. squaring of the vertebral body 4. marginal syndesmophyte (ossification of the outer annulus fibrosus fibers) 3. bamboo spine 1. continuous marginal syndesmophytes giving a bamboo stalk appearance indicating ankylosis 4. ankylosis of the facet joints 5. trolley track sign on AP view 6. central line of ossification (supraspinous and interspinous ligaments ) with 2 lateral lines of ossificaiton (facet joints) 7. osteopenia 8. dural ectasia

Answer 140

Lower cervical spine followed by thoracolumbar junction

Answer 141

1. Unstable 2. Higher prevalence of neurologic injury 3. Higher risk of epidural hematoma and aortic dissection 4. Higher risk of multiple fractures 5. Typically occur through the ossified disc and vertebral body 6. Frequently due to extension-distraction mechanism (opening of the anterior column)

Answer 142

1. Osteoporosis * Leads to higher rate of vertebral fractures and higher risk from low-energy trauma 2. Loss of flexibility * Long lever arms (behave like long bones) 3. Kyphotic deformity

Answer 143

1. Radiographs * Often nondiagnostic 2. CT scan (full spine) * Routine use in patient with suspected cervical fracture 3. MRI (full spine) * Detects epidural hematoma in patients with neurological deficit * Detects spinal cord and soft tissue injury * May detect fractures missed on CT

Answer 144

1. Protect against iatrogenic neurological deterioration * Immobilize patient in their typical position * Do not force head to spine board (extension) as they often have an increased occiput to wall distance * Take care during transfers 2. Anaesthesia considerations * Difficult intubation (chin to chest deformity) 3. Positioning * Restore their normal alignment 4. Construct length * Longer construct preferred due to osteoporosis and long lever arm (treat like long bone) * Usually 3 vertebral levels above and below

Answer 145

Posterior instrumentation and fusion * Anterior alone is possible but more difficult due to chin-to-chest deformity and has higher failure rate * Anterior and posterior can be considered if correcting the deformity (not generally recommended)

Answer 146

Posterior instrumentation and fusion

Answer 147

L1 vertebral body (T12-L2 vertebra)

Answer 148

1. Collection of peripheral nerves (L1-S5) in a common dural sac within the lumbar spinal canal 2. Therefore, lesions involving the cauda equina are lower motor neuron lesions

Answer 149

* Herniated lumbar disc * Spinal stenosis * Tumour * Trauma * Epidural hematoma * Epidural abscess * Iatrogenic

Answer 150

1. Bladder dysfunction (required element) * Difficulty initiating stream → urinary retention → overflow incontinence 2. Bowel dysfunction 3. Saddle anaesthesia * Dense sensory loss involving the perineum, buttocks, and posteromedial thighs * Late sign 4. Low back, groin, perineal pain 5. Unilateral or bilateral sciatica * Bilateral is strongly associated with CES 6. Lower extremity weakness and sensory deficits

Answer 151

1. Reduced sensation to pinprick in the perianal, perineum and posterior thigh 2. Decreased rectal tone 3. Lack of anal contraction with anal wink and bulbocavernosus test 4. Full bladder on palpation 5. Lower extremity hyporeflexia, sensory deficits and weakness

Answer 152

Urgent manner within 48 hours of symptom onset * Current literature does not demonstrate improved outcomes with surgery performed within 24 hours as opposed to 48 hours

Answer 153

Spinal decompression in a timely manner to avoid permanent disability * Disability including bowel/bladder dysfunction, motor deficit, sensory deficit, sexual dysfunction

Answer 154

Sacral sparing * Evaluation consists of perianal sensation, rectal tone and activity of the great toe flexor

Answer 155

Central cord syndrome

Answer 156

1.Older patient (\>60) * Underlying cervical spondylosis * Hyperextension injury * No evidence of bony spine injury 2. Younger patient * No underlying cervical spondylosis * High-energy mechanism * Associated fractures and/or dislocations 3. Younger patient with congenital stenosis * Hyperextension injury 4. Younger patient with traumatic disc herniation * No spinal fracture or dislocation

Answer 157

Classically: * Motor more affected than sensory function * Upper extremity more affected than lower extremity * Distal more than proximal * Hands and forearms most affected * Bladder (urinary retention), bowel and sexual dysfunction in severe cases * Sacral sparing

Answer 158

Lower extremities → bowel/bladder control → upper extremity → hand * Motor recovery occurs caudal to cephalad (toe flexors are first to return) * Recovery is usually less complete in upper extremities compared to lower extremities * Hand recovery is variable (most common long term disability)

Answer 159

1. Medical management * ICU monitoring * Adequate BP (MAP \>85mmHg) * Hard cervical collar * Use for at least 6 weeks or until neck pain has resolved and associated neurological improvement is noted * Early mobilization 2. Surgery * Absolute indication = spinal instability * Defined as angular displacement \>11° or vertebral body translation \>3.5mm * Early surgery is recommended 2 situations: * Overt spinal instability with acute dislocation * Progressive neurological deficit

Answer 160

1. OPLL (greatest risk factor for cervical spine surgery) 2. Revision surgery 3. Surgeon inexperience 4. Age * Due to: * Narrowing of the spinal canal * Thicker ligamentum flavum * Osteophyte formation * Redundant dura due to shortening of the spine

Answer 161

1. Spinocutaneous fistula 2. Pseudocyst 3. Meningitis 4. Nerve root entrapment 5. Cranial nerve palsy 6. Mass effect 7. Wound healing complications and infections

Answer 162

1. Direct visualization of the tear 2. Pulsatile clear fluid from a dry field 3. Pulsatile light swirl of fluid in a bloody field 4. Repeat bleeding in areas previously controlled

Answer 163

1. Ensure proper visualization * Dry field * Adequate hemostasis * Loupes or microscope 2. Primary repair when possible * Augment as necessary * Fat grafts, fibrin glue, collagen matrix, hydrogels * Dural grafts when primary closure not possible * Fascia lata, lumbodorsal fascia 3. Test the repair for watertight closure * Deflated dura should inflate in pulsatile fashion * Test repair with Valsalva * Duration of 15-20 sec, supine posture, and 40 mmHg intrathoracic pressure [Can J Anesth (2018) 65: 578.] 4. Tight fascial and wound closure in layers 5. Bedrest until symptoms of CSF leak resolve * Cervical durotomy – position patient upright * Lumbar durotomy – position patient supine * Symptoms managed with opiods, NSAIDs, antiemetics, caffeine

Answer 164

* Positional headache * Nausea * Photophobia * CSF leak from wound or subfascial drain

Answer 165

B-2 transferrin assay

Answer 166

1. Narrow range of posture positioning in which the body can remain balanced without external support 2. Most persons with symptomatic sagittal plane deformity present with alignment at the periphery of this cone

Answer 167

1. Thoracic kyphosis = 10-40° * Measured via Cobb method from superior end plate of T2 to inferior endplate of T12 2. Lumbar lordosis = 40-60° * Measured via Cobb method from superior endplate of T12 to superior endplate of S1 * Should be 30° more than the thoracic kyphosis 3. C7 plumb line = pass within a few millimeters of the posterior-superior corner of S1 * Vertical line dropped from center of C7 vertebral body * If line falls posterior = negative sagittal balance * If line falls anterior = positive sagittal balance * Abnormal = \>2.5cm anterior or posterior to posterior-superior corner of S1 4. Pelvic incidence (PI) * Angle formed between the line perpendicular to the sacral endplate at its midpoint and a line from this midpoint to the center of the femoral head * PI = SS+PT 5. Sacral slope (SS) * Angle formed between line parallel to the superior endplate of S1 and a horizontal line extending from the anterior-inferior corner of that endplate 6. Pelvic tilt (PT) * Angle formed between line from the midpoint of the superior sacral endplate and the center of the femoral head and a vertical line extending from the center of the femoral head

Answer 168

1. Hip hyperextension 2. Knee flexion

Answer 169

1. Full length 36 inch AP and lateral radiographs 2. Full length lateral flexion and extension radiographs as well as hyperextension films with a bolster placed at apex of deformity to assess flexibility of deformity

Answer 170

1. Multilevel degenerative disc disease 2. Iatrogenic * Flat back syndrome * Due to distraction instrumentation posteriorly or compressive anterior instrumentation 3. Osteoporosis 4. Ankylosing spondylitis

Answer 171

1. Failure of nonoperative treatment 2. Documented curve progression 3. Significant cosmetic deformity that is unacceptable for the patient 4. Back pain 5. Radicular symptoms 6. Functional deficit resulting from the deformity

Answer 172

1. Smith-Peterson Osteotomy * Posterior column is shortened and anterior column is lengthened * Requires a mobile disc or osteotomized anterior fusion mass * The osteotomy hinges on the posterior aspect of the disc * Posterior pedicle screw instrumentation is required to maintain closure of the osteotomy 2. Pedicle Subtraction Osteotomy * Posterior column is shortened without lengthening the anterior column * The osteotomy hinges through the anterior cortex * Posterior pedicle screw instrumentation is required * At least 3 levels above and below 3. Vertebral Column Resection * One or more vertebral segments is removed * Includes posterior elements, pedicles and entire vertebral body as well as disc above and below * Anterior and posterior reconstruction required * Anterior cage with posterior pedicle screw instrumentation

Answer 173

1. SPO * 10° of lordosis (per level) * If patient requires 10-20° of lordosis or 4-7cm of correction of the plumb line – perform limited number of SPO rather than one PSO 2. PSO * One PSO = Two SPO * Above and below a pair of pedicles * ~35° (30-40^o) of lumbar lordosis and 25° of thoracic kyphosis can be achieved with PSO

Answer 174

1. Sagittal imbalance >10cm 2. Sharp, angular kyphosis 3. Circumferential fusion along multiple segments

Answer 175

* Congenital kyphosis * Severe sagittal plane deformity plus coronal plane deformity * Spondyloptosis * Resectable spinal tumor

Answer 176

* Greater patient age (\>55 years) * Longer fusions (\>12 vertebrae) * Thoracolumbar kyphosis (\>20°) * Osteoarthritis of the hip joint * Positive sagittal balance ≥5 cm at 8 weeks postoperatively * Incomplete sacropelvic fixation

Answer 177

1. Fusion 2. Reduction of sagittal deformity 3. Restoring lumbar lordosis

Answer 178

Spine * Thoracic \> lumbar \> cervical

Answer 179

Hematogenous * Via the arterial supply and the valveless venous complex (Batson plexus)

Answer 180

Modified Tokuhashi scoring system * high score is good, low score is bad * 6 components * Karnofsky performance status * Number of extraspinal metastases foci * Number of metastases in the vertebral body * Metastases to the major internal organs * Primary site of cancer * Palsy (neurological status) * Score: * 0-8 = life expectancy ≤ 6 months * Conservative treatment versus palliative * 9-11 = life expectancy ≥ 6 months * Palliative surgery * 12-15 = life expectancy ≥1 year * Excisional surgery

Answer 181

SINS (Spinal Instability Neoplastic Score) * 6 components * Location * Pain * Bone lesion * Radiographic spinal alignment * Vertebral body collapse * Posterolateral involvement of spinal elements * Score: * 0-6 = stable * 7-12 = impending instability * 13-18 = unstable

Answer 182

1. Nonoperative * Radiosensitive and chemosensitive tumors in neurologically intact patients 2. Operative * Spinal instability * Neurological deficit requiring surgical decompression * Rapid deterioration in function * Intractable mechanical pain * Need for histological diagnosis

Answer 183

1. Preoperative embolization of RCC, thyroid and hepatocellular cancers 2. Intralesional resection followed by stabilization * C1/2 * Posterior instrumentation with occipital plating * +/- transpedicular corpectomy and anterior stabilization * Subaxial cervical spine * Anterior corpectomy with anterior and posterior instrumentation and fusion * Cervicothoracic * Corpectomy (low anterior or transpedicular) with anterior and posterior instrumentation and fusion * Thoracolumbar * Anterior decompression and stabilization with transpedicular approach + posterior instrumentation 3. Conventional radiotherapy * 3-4 weeks following surgery

Answer 184

1. A decision making framework for making treatment decisions in patients with spinal metastasis 2. Considers 4 factors: * Neurologic * Degree of spinal cord compromise * Radiographic assessment (degree of epidural spinal cord compression) * Oncologic * Radiosensitive vs. radioresistant tumors * Mechanical (instability) * Mechanical pain (movement related) * SINS score * Systemic * Ability of patient to tolerate intervention 3. Determines treatment options based on above factors including: * Conventional external beam radiation * Stereotactic radiosurgery * Decompression/separation surgery * Stabilization surgery

Answer 185

Radiosensitive = “NOMS LBP” * Neuroendocrine (carcinoid/pancreatic) * Ovarian * Myeloma * Seminoma * Lymphoma * Breast * Prostate Radioresistant = “SMRT Cancers” * Sarcoma * Melanoma * Renal * Thyroid * Colorectal * adenocarcinoma lung

Answer 186

1. Location = primarily posterior elements 2. Presentation * Back pain, often night pain, relieved with NSAIDs * Avg age is 19 * Most common cause of painful scoliosis in adolescents * Lesion typically on concavity of curve 3. Imaging * Radiographs – area of sclerosis * CT – better defines lesion * MRI – better for preop planning to assess proximity to neural structures 4. Treatment * Nonoperative – first line (NSAIDs) * Radiofrequency thermal ablation – failed nonop * En bloc resection – indicated for: * Fixed spinal deformity * Neurological compression * RFA unsafe

Answer 187

1. Location = posterior elements 2. Presentation * Dull back pain, possible neural compression * Differs from osteoid osteoma in that not worse at night, does not respond to NSAIDs, less frequently associated with scoliosis 3. Imaging * Radiographs * Compared to osteoid osteoma: * Multiple calcifications * Aggressive bony destruction * Infiltration into surrounding tissues * CT – better defines lesion and location * MRI – better assess neural and soft tissue involvement 4. Treatment * En bloc resection +/- fusion if instability created

Answer 188

1. Location = posterior elements 2. Presentation * Slow, gradual onset of pain * Possible palpable mass and spinal deformity 3. Imaging * Radiographs – lytic, expansile * CT – characteristic septate pattern with cortical expansion and erosion * MRI – better for neural and soft tissue involvement * Fluid-fluid levels on T2 4. Treatment * Marginal resection

Answer 189

1. Location = posterior elements of the spine 2. Presentation = pain and/or swelling 3. Imaging * Radiographs – difficult to interpret, spinal deformity * CT – determines connection of medullary cavity of lesion with vertebra * MRI – determines thickness of cartilage cap 4. Treatment * Complete resection +/- fusion for instability if lesion symptomatic

Answer 190

1. Location = cervical and thoracic most commonly 2. Presentation = pain, scoliosis, nerve root compression 3. Imaging * Radiographs = sharp angular scoliosis * Erosion or scalloping * Rib thinning * CT = vertebral destruction * MRI = surgical planning 4. Treatment * En bloc resection of symptomatic lesions * Treat scoliosis with anterior and posterior fusions

Answer 191

1. Location = vertebral body 2. Presentation = back pain, spinal cord compression 3. Imaging * Radiographs = expansile, lytic lesion * Compression fractures * CT and MRI = define bone, soft tissue and neural involvement * CT chest = pulmonary mets 4. Treatment * En bloc resection * Resection with adjuvants if incomplete resection * Sacrum and cervical spine * Denosumab

Answer 192

1. Location = vertebral body 2. Presentation = back pain, restricted ROM * Deformity * Age usually \<10 3. Imaging * Radiographs = lytic lesion of vertebral body * 40% present as vertebra plana - severe compression fracture appearance * Skeletal survey or bone scan * MRI = confirms diagnosis and associated soft tissue mass 4. Treatment * Nonoperative * Usually spontaneously resolves * Consider analgesia, orthoses, intralesional CT guided steroid * Chemo if systemic disease

Answer 193

1. Location = vertebral body 2. Presentation = asymptomatic, incidental 3. Imaging * Radiographs – corduroy pattern with vertical striations * CT – punctuate sclerotic foci * MRI – hyperintense on T1 and T2 4. Treatment * If symptomatic consider: * Radiation * Intralesional ethanol * Embolization * Vertebroplasty/kyphoplasty

Answer 194

1. Hard palate – arch of the atlas 2. Lower border of the mandible – C2-C3 3. Hyoid – C3 4. Thyroid cartilage – C4-C5 5. Cricoid cartilage – C6 6. Carotid tubercle – C6 (anterior tubercle on C6 TP)

Answer 195

1. Transverse skin incision at appropriate level 2. Incise fascia in line with skin incision over platysma 3. Split platysma longitudinally bluntly 4. Incise investing layer of deep cervical fascia medial to anterior border of SCM 5. Retract SCM lateral and strap muscle medial 6. Palpate the carotid artery 7. Incise the pretracheal fascia medial to the carotid sheath 8. Retract the carotid sheath lateral and the trachea and esophagus medial * Proximally, the superior and inferior thyroid arteries pass from the carotid sheath to the midline, may require ligation 9. Incise the prevertebral fascia, longus colli and ALL longitudinally in the midline * Avoid the sympathetic chain laterally over the TPs 10. Elevate subperiosteally and retract muscle laterally to expose vertebral bodies and disc 11. Identify the level with a needle in the disc space with a lateral fluoro view

Answer 196

2 level discectomy or 1 level corpectomy

Answer 197

1. Superior thyroid artery 2. Inferior thyroid artery 3. Ansa cervicalis (loop of nerves in cervical plexus) 4. Hypoglossal nerve 5. Omohyoid muscle

Answer 198

1. Recurrent laryngeal nerve (right \> left) 2. Sympathetic chain and stellate ganglion (C6) 3. Carotid sheath contents 4. Esophagus 5. Trachea 6. Postoperative retropharyngeal hematoma * Presents with respiratory difficulties * Requires emergent decompression

Answer 199

1 .ENT consult to assess for occult recurrent laryngeal nerve injury via laryngoscopy * If no injury = opposite side * If injury = same side 2. Bilateral recurrent laryngeal nerve injury results in abductor vocal cord paralysis and potential airway obstruction

Answer 200

1.Positioning * Prone with Mayfield head holder * Goal of neutral head position (flexion/extension) 2. Approach * Posterior from EOP to lower planned instrumented vertebra 3. Fixation * Occipital plate * Placed just below the level of the EOP * Bone is thickest in the midline and purchase is greatest * Bicortical or unicortical screws can be used (bicortical biomechanically stronger) * If poor midline purchase achieved, additional fixation can be achieved laterally * Cervical fixation * C1 lateral mass * Often omitted depending on pathology * C2 pars/pedicle * Lower cervical lateral mass (depending on pathology) * Rod contoured and connected to plate and screws 4. Fusion preparation * Decortication to bleeding bone of the arch of C1, posterior occiput, C2, and other fusion levels is completed using a high-speed burr * Bone grafting is performed using local bone and autologous iliac crest

Answer 201

1. Dissection is inferior to the posterior arch of C1 2. C2 nerve root is retracted caudally 3. Start point is at the inferior aspect of the posterior lateral mass in the midline 4. Starting hole is created with a 2.5mm burr then 2.5mm drill by handpower angled ~10° medial

Answer 202

1. C2 Pars Screw [Operative Techniques in Spine Surgery; Wiesel 2016] * The starting point of the C2 pars screw is 2 mm superior and lateral to the inferior C2-C3 articulation * It is placed in a craniocaudal trajectory similar to the transarticular screw but does not need to be aimed as much cephalad * It is aimed 20 to 25 degrees medial 2. C2 pedicle screw [Operative Techniques in Spine Surgery; Wiesel 2016] * The starting point of the C2 pedicle is in the midline of the C2-C3 facet joint, 3 to 5 mm cranial to the C2-C3 articulation * The trajectory is 25 degrees of medial convergence and is aimed 25 degrees cephalad

Answer 203

1. The quadrilateral posterior surface of the lateral mass is clearly exposed 2. Roy Camille * Start point center of the lateral mass * Directed perpendicular to the posterior lateral mass and 10° lateral 3. Magerl * Start point inferior and medial * Directed 30° lateral and 15° cephalad * This trajectory aims to exit lateral to the vertebral artery and superior to the exiting nerve root

Answer 204

1. Anaesthesia * Awake fiberoptic intubation 2. Positioning/setup * Supine, bump under shoulders, bite block, halter traction * Biplanar fluoroscopy 3. Approach * Anterior approach starting at level of C5/C6 4. Fixation * An entry site on the anterior inferior edge of C2 is chosen and confirmed on AP and lateral fluoroscopy * One midline site for one screw * Two paramedian sites about 2 to 3 mm from the midline for two screws * K-wire is placed into start point followed by inner and outer drill guide tubes over the K-wire * Under biplanar fluoro the drill is passed through the C2 body, into the odontoid and penetrates the apical cortex * Depth is measured off calibrated drill * Inner guide is removed and tap is inserted * A 4mm partially threaded lag screw is inserted and should engage the apical cortex * Traction should be removed as screw is tightened * A second screw can be inserted by the same technique if anatomy allows * Confirm stability under fluoro with flexion and extension of the head

Answer 205

1. Supine 2. Approach * Standard Smith-Robinson at planned level 3. Confirm levels with fluoro 4. Perform discectomy from uncus to uncus as far posterior as the PLL * Generally remove PLL to visualize cord * The uncinates define the safe zone for the vertebral artery 5. Prepare endplates * Thoroughly denuded of cartilage and decorticated * Alternating use of the high-speed burr, curettes, and the pituitary rongeur (or rasp) 6. Perform anterior foraminotomy * Alternating between microcurettes or a Kerrison and the burr, the foramen can be gently and progressively carved out laterally * Foraminotomy is complete when a micro nerve hook or curette can easily be passed into the foramen anterior to the exiting root without resistance 7. Graft sizing and placement * The final height of the graft can be determined after endplate preparation with sizers that accompany commercial grafts * Prefer to use commercially prepared cortical allografts for ACDF 8. Select and fix anterior plate * Once the graft has been placed, the size of the plate is then determined * Optimal plate length is one that allows for the screws to be immediately adjacent to the endplates

Answer 206

1. Supine 2. Approach * Standard Smith-Robinson at planned level 3. Confirm levels with fluoro 4. Perform discectomy from uncus to uncus as far posterior as the PLL (generally remove PLL to visualize cord) * The uncinates define the safe zone for the vertebral artery * Perform above and below level of planned corpectomy, corpectomy is completed inline 5. Endplate preparation * The endplates above and below the corpectomy should be thoroughly decorticated and denuded of all cartilaginous material 6. Graft selection * Allograft fibula or cages filled with local autograft remain popular choices * Autograft available from corpectomy * Autograft options include structural iliac crest or autologous fibula 7. Graft inserted and anterior plating