Orthopedic Board Review: Spine Surgery MCQs Part 27

Question 1

A 17-year-old male presents with slowly progressive, asymmetric weakness and atrophy of the right hand and forearm intrinsic muscles. Sensation is intact, and reflexes in the lower extremities are normal. Dynamic flexion MRI of the cervical spine reveals anterior displacement of the posterior dura with flattening of the lower cervical cord. What is the most appropriate initial management?

Explanation

This patient has Hirayama disease (cervical flexion-induced myelopathy), a rare disorder typically affecting young males. Pathophysiology involves forward displacement of the posterior dural sac during neck flexion, leading to microtrauma and ischemia of the anterior horn cells of the lower cervical cord. First-line treatment is conservative with a hard cervical collar to prevent neck flexion. Surgery is reserved for progressive cases failing conservative management.

Question 2

An adult patient with sagittal imbalance is being planned for a spinal deformity correction. The surgeon aims to restore a harmonious profile. The patient's Pelvic Incidence (PI) is measured at 55 degrees. According to the SRS-Schwab adult spinal deformity classification, which of the following is the target Lumbar Lordosis (LL) to minimize the risk of adjacent segment disease and mechanical failure?

Explanation

The SRS-Schwab classification for adult spinal deformity emphasizes sagittal spinopelvic parameters. A key goal for sagittal realignment is to achieve a PI-LL mismatch of less than 10 degrees. Ideally, PI and LL should be roughly equal. For a PI of 55 degrees, an LL of 55 degrees provides an optimal spinopelvic balance, keeping the mismatch well within the safe threshold of +/- 9 degrees.

Question 3

A 62-year-old male undergoes a C3-C6 posterior cervical laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 2, he develops isolated profound weakness in right shoulder abduction and elbow flexion. Sensation is relatively preserved, and there is no new lower extremity deficit. What is the most likely etiology of this complication?

Explanation

The patient has developed a postoperative C5 palsy, a well-known complication after cervical decompression (especially posterior laminectomy or laminoplasty). The most widely accepted mechanism is the tethering effect on the C5 nerve root due to the posterior drift of the spinal cord after decompression. The C5 root is particularly vulnerable due to its short, transverse course. Most cases recover spontaneously with physical therapy over several months.

Question 4

A 25-year-old male is involved in a high-speed motor vehicle collision. CT scan of the cervical spine reveals a traumatic spondylolisthesis of the axis with a bilateral pars interarticularis fracture. There is minimal anterior translation of C2 on C3, but severe angulation is present, and the C2-C3 disc space is widened posteriorly. According to the Levine and Edwards classification, what type of fracture is this, and what is the typical mechanism of injury?

Explanation

This is a Type IIa Hangman's fracture. According to the Levine and Edwards classification, Type IIa fractures show minimal translation but severe angulation, and the posterior C2-C3 disc space is widened. The mechanism is flexion and distraction. Notably, these fractures must NOT be placed in traction, as traction will exacerbate the distraction and instability. They are managed with gentle reduction in extension and compression, typically followed by a halo vest.

Question 5

During an anterior exposure of the thoracolumbar spine for corpectomy and stabilization of a burst fracture, the surgeon must be mindful of the artery of Adamkiewicz to prevent anterior spinal artery syndrome. In the majority of the population, at which vertebral levels does this artery typically enter the spinal canal?

Explanation

The artery of Adamkiewicz (arteria radicularis magna) is the major anterior radicular artery supplying the lower two-thirds of the spinal cord. It typically arises from a left posterior intercostal or lumbar artery between the T9 and L1 vertebral levels in approximately 75-80% of individuals. Injury to this artery during anterior thoracolumbar surgery can lead to devastating ischemia of the anterior spinal cord.

Question 6

A 60-year-old female with breast cancer presents with severe thoracic back pain exacerbated by movement. An MRI reveals a lytic metastatic lesion at T8. According to the Spinal Instability Neoplastic Score (SINS), which of the following lesion characteristics is considered the MOST unstable (scores the highest number of points) in its respective category?

Explanation

In the Spinal Instability Neoplastic Score (SINS), radiographic alignment is a critical component. Subluxation or translation assigns the highest single score in the entire system (4 points). Comparatively, an osteolytic lesion gives 2 points, unilateral posterolateral involvement gives 1 point, >50% collapse gives 3 points, and a semi-rigid location (T3-T10) gives 1 point. A total score of 13-18 indicates frank instability warranting surgical consultation.

Question 7

A 55-year-old diabetic male presents with 2 weeks of worsening mid-back pain, fevers, and recent onset of bilateral lower extremity weakness (motor strength 3/5). MRI reveals T8-T9 discitis/osteomyelitis with a large ventral epidural abscess severely compressing the spinal cord. What is the most appropriate surgical approach for decompression and stabilization?

Explanation

The patient has a ventral epidural abscess secondary to discitis/osteomyelitis with profound neurologic deficits, necessitating emergent surgical decompression. Because the pathology is ventral and involves destruction of the anterior load-bearing structures (disc/bone), an anterior approach (corpectomy) is required for direct decompression of the cord and debridement, followed by anterior structural support. A posterior laminectomy alone is contraindicated as it fails to address the ventral pathology and further destabilizes the spine.

Question 8

A 32-year-old male is evaluated in the emergency department after a diving accident. He is awake and alert but has bilateral upper and lower extremity weakness. Plain radiographs and CT demonstrate a bilateral C5-C6 facet dislocation. MRI reveals a large, extruded disc herniation behind the C5 vertebral body causing severe cord compression. What is the most appropriate sequence of surgical management?

Explanation

In the setting of a bilateral facet dislocation with a large ventral disc herniation (a 'disc in the way'), performing closed traction reduction or a posterior open reduction first can pull the herniated disc material into the spinal canal, potentially causing permanent catastrophic neurologic injury. The safest approach is an anterior cervical discectomy to remove the herniated disc first, followed by anterior reduction and fusion.

Question 9

A 15-year-old male presents with cosmetic concerns regarding a rounded upper back and mild, intermittent ache over the thoracic spine after physical activity. Lateral radiographs reveal a thoracic kyphosis of 65 degrees. According to Sorensen's criteria, which of the following radiographic findings confirms the diagnosis of classic Scheuermann's kyphosis?

Explanation

Classic Scheuermann's kyphosis is defined radiographically by the Sorensen criteria, which require anterior wedging of at least 5 degrees in three or more consecutive vertebrae. While other findings like Schmorl's nodes, endplate irregularities, and disc space narrowing are commonly associated, the consecutive anterior wedging is the sine qua non for the diagnosis.

Question 10

A 65-year-old male with a long-standing history of ankylosing spondylitis presents with localized, progressive lower thoracic back pain after a minor fall 3 months ago. He has no neurologic deficits. Plain radiographs demonstrate a radiolucent gap involving the intervertebral disc space and adjacent endplates at T11-T12, with surrounding sclerosis. CT confirms a pseudoarthrosis at this level. What is the most appropriate management?

Explanation

The patient has an Andersson lesion, which in the context of ankylosing spondylitis represents a pseudoarthrosis or nonunion of a fractured ankylosed spinal segment. Due to the long rigid lever arms of the fused spine above and below the fracture, these lesions are highly unstable and rarely heal with non-operative management. The standard of care is surgical stabilization utilizing long-segment posterior instrumented fusion.

Question 11

A 3-year-old female is referred for an asymptomatic progressive spinal deformity. Radiographs demonstrate a fully segmented hemivertebra at L2, resulting in a 35-degree scoliotic curve. Given the natural history of this specific anomaly, what is the most appropriate management?

Explanation

Congenital scoliosis due to a fully segmented hemivertebra has a high risk of progression (often 2-3 degrees per year). Bracing is ineffective for congenital curves. Early surgical intervention is recommended before the deformity becomes severe and secondary structural changes occur. Hemivertebra excision with short segment fusion is the treatment of choice in young children.

Question 12

During a routine L4-L5 microdiscectomy, an incidental 4 mm dural tear occurs ventrolaterally, which is inaccessible for primary suture repair. Cerebrospinal fluid is actively pooling in the surgical field. What is the most appropriate next step in management?

Explanation

When a small dural tear occurs that is inaccessible for primary suture repair (such as a ventral or ventrolateral tear), the standard of care is to use dural patch/sealant techniques (like synthetic dural substitutes, muscle grafts, and fibrin glue) combined with a meticulous, watertight closure of the overlying fascia. Fascial drains on suction can create a continuous CSF fistula and should be avoided.

Question 13

A 68-year-old male presents with bilateral leg pain and heaviness that occurs after walking 2 blocks. During a stationary bicycle test, he experiences significant leg cramping and pain when pedaling in an extended spine posture. However, his symptoms persist even when he leans completely forward over the handlebars while continuing to pedal. What is the most likely diagnosis?

Explanation

The stationary bicycle test (van Gelderen test) differentiates neurogenic from vascular claudication. Patients with neurogenic claudication (from lumbar stenosis) experience relief when leaning forward (flexing the spine increases the cross-sectional area of the spinal canal). If symptoms persist during cycling despite spinal flexion, it suggests vascular claudication, as the metabolic demand of the leg muscles exceeds the arterial blood supply regardless of spine posture.

Question 14

A 78-year-old female presents after a ground-level fall. CT scan reveals a displaced Anderson and D'Alonzo Type II odontoid fracture with 6 mm of posterior translation. She is neurologically intact. Which of the following factors is most strongly associated with a high rate of nonunion for this fracture type if managed conservatively with a rigid collar?

Explanation

Type II odontoid fractures have a notoriously high rate of nonunion due to poor local vascularity at the base of the dens. Major risk factors for nonunion include patient age older than 50 years, initial displacement > 5 mm, posterior displacement (more so than anterior), and a fracture gap > 1 mm. Given her age and displacement, conservative management has a very high failure rate.

Question 15

A 55-year-old male presents with progressive sacral pain and bowel/bladder dysfunction. MRI reveals a large, lobulated, destructive mass in the sacrum (S2-S4) with a hyperintense signal on T2-weighted images. Histopathology from a CT-guided biopsy shows physaliferous cells in a myxoid background. What is the most appropriate surgical treatment aiming for long-term disease-free survival?

Explanation

The presence of physaliferous cells is pathognomonic for a chordoma, a low-grade, locally aggressive malignant primary bone tumor arising from notochordal remnants. Chordomas are largely resistant to conventional chemotherapy and standard radiation. The gold standard treatment aiming for cure or maximal local control is en bloc wide surgical resection with negative margins.

Question 16

A 13-year-old female gymnast presents with persistent lower back pain for 6 months. Lateral radiographs show a grade 1 isthmic spondylolisthesis at L5-S1. MRI demonstrates bilateral pars defects with prominent marrow edema on STIR sequences, but no central canal stenosis. She has failed 6 weeks of rest and NSAIDs. What is the most appropriate next step in management?

Explanation

This patient has an acute/subacute isthmic spondylolisthesis (pars stress fracture), indicated by the marrow edema on STIR MRI. In young athletes with early/active pars defects and low-grade slips, the standard initial treatment is a prolonged period of rigid bracing (TLSO or antilordotic brace) and cessation of the offending sports activity for 3 to 6 months to allow for bony healing. Surgery is reserved for patients failing prolonged conservative care.

Question 17

A 45-year-old male presents with right-sided neck pain radiating down his arm to his middle finger. He notes weakness in triceps extension and an absent triceps reflex. A Spurling test reproduces his symptoms. Which cervical nerve root is most likely compressed, and between which two vertebrae does this nerve exit?

Explanation

The patient exhibits classic signs of a C7 radiculopathy: pain radiating to the middle finger, triceps weakness, and a diminished/absent triceps reflex. In the cervical spine, the nerve roots exit above their corresponding numbered pedicle (e.g., the C7 nerve root exits through the C6-C7 neural foramen). Therefore, a C6-C7 disc herniation typically compresses the C7 nerve root.

Question 18

A 65-year-old male with known cervical spondylosis sustains a hyperextension injury. He presents with bilateral upper extremity weakness (motor strength 2/5 in the hands) and mild lower extremity weakness (motor strength 4/5). MRI reveals severe multi-level cervical stenosis, worse at C4-C5, with intramedullary T2 hyperintensity. According to recent AOSpine guidelines, what is the recommended timing for surgical decompression?

Explanation

The patient has Acute Traumatic Central Cord Syndrome (ATCCS). Historically, management was delayed or conservative. However, recent literature and AOSpine guidelines recommend early surgical decompression (typically within 24 hours) for patients with ATCCS and ongoing cord compression. Early surgery yields superior neurologic recovery and shorter hospital stays compared to delayed surgery.

Question 19

A 72-year-old female with profound osteoporosis presents with severe back pain 3 weeks after lifting a box. Imaging confirms an acute, isolated T12 osteoporotic vertebral compression fracture (VCF) with 30% anterior height loss and no retropulsion. Pain is not adequately controlled with oral analgesics and a brace. Which of the following is true regarding balloon kyphoplasty compared to non-operative management for this condition based on randomized controlled trials?

Explanation

According to major randomized controlled trials (such as the FREE trial), balloon kyphoplasty provides faster and superior early pain relief and improvement in functional status compared to non-operative management during the first few months. However, by 1 to 2 years, the pain and functional outcomes between the operative and non-operative groups generally equalize. Cement augmentation carries a well-documented risk of adjacent segment fractures.

Question 20

A 4-month-old infant is noted to have a hairy patch and a sacral dimple above the gluteal crease. MRI confirms a thickened filum terminale and a conus medullaris terminating at the L4 level. What is the specific embryological defect primarily responsible for this tethered cord syndrome?

Explanation

The development of the lower sacral and coccygeal segments of the spinal cord occurs via secondary neurulation. During the subsequent phase of retrogressive differentiation, the terminal portion of the neural tube undergoes atrophy to form the filum terminale, allowing the conus medullaris to ascend. Failure of this process leads to a thickened filum terminale and a low-lying, tethered conus medullaris. Primary neurulation defects result in open defects like myelomeningocele.

Question 21

A 6-year-old child with Down syndrome is evaluated for neck pain. Radiographs show an anterior atlantodental interval (ADI) of 6 mm. What is the most reliable radiographic predictor for the development of neurologic deficit in this patient?

Explanation

The Space Available for the Cord (SAC), also known as the posterior atlantodental interval (PADI), is the most reliable predictor of neurologic injury. A SAC of less than 14 mm is highly correlated with the development of myelopathic symptoms in atlantoaxial instability.

Question 22

A 45-year-old man presents with acute onset of severe anterior thigh pain, weakness in knee extension, and a diminished patellar reflex. MRI of the lumbar spine reveals a far-lateral extraforaminal disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

Explanation

A far-lateral (extraforaminal) disc herniation compresses the exiting nerve root at the same level. Therefore, an L4-L5 far-lateral herniation directly compresses the exiting L4 nerve root.

Question 23

A 32-year-old female is involved in a motor vehicle accident and sustains a Levine-Edwards Type IIA traumatic spondylolisthesis of the axis (Hangman's fracture). The fracture shows severe angulation with minimal translation. What is the most appropriate initial management?

Explanation

Type IIA Hangman's fractures are caused by flexion-distraction injuries resulting in severe angulation but minimal translation. Axial traction is strictly contraindicated as it can over-distract the fracture and cause spinal cord injury; management involves slight compression and extension in a Halo vest.

Question 24

A 72-year-old man with a history of cervical spondylosis presents with severe bilateral upper extremity weakness and numbness after a hyperextension injury. His lower extremity strength is only mildly diminished, and he retains bowel and bladder control. Which of the following tracts is most centrally located and responsible for the disproportionate upper extremity weakness?

Explanation

Central cord syndrome typically occurs after a hyperextension injury in a stenotic cervical spine. The disproportionate upper extremity weakness is due to the somatotopic organization of the lateral corticospinal tract, where cervical motor fibers are located more centrally and medially than lumbar and sacral fibers.

Question 25

A surgeon considers using recombinant human bone morphogenetic protein-2 (rhBMP-2) to augment a spinal fusion. In which of the following scenarios is the use of rhBMP-2 associated with the highest risk of life-threatening complications, prompting an FDA warning?

Explanation

The FDA issued a public health warning regarding the off-label use of rhBMP-2 in anterior cervical spine surgery. Its use in ACDF is associated with massive prevertebral soft tissue swelling, which can lead to life-threatening dysphagia and airway compromise.

Question 26

According to the Lenke classification for adolescent idiopathic scoliosis, a curve is considered structurally significant and should be included in the fusion construct if the Cobb angle fails to reduce below what threshold on side-bending radiographs?

Explanation

In the Lenke classification system, a minor curve is considered structural if it does not bend down to less than 25 degrees on lateral side-bending radiographs. Structural curves must be included in the final fusion construct to maintain overall coronal balance.

Question 27

A 15-year-old male presents with postural thoracic back pain and a prominent thoracic kyphosis. Radiographs are obtained to evaluate for Scheuermann's disease. According to the Sorensen criteria, what radiographic finding is required to confirm the diagnosis?

Explanation

The classic Sorensen criteria for Scheuermann's kyphosis require the presence of greater than 5 degrees of anterior wedging in at least three consecutive thoracic vertebrae. Associated findings often include Schmorl's nodes and endplate irregularities, but are not strictly required for the criteria.

Question 28

A 14-year-old female with an L5-S1 Meyerding Grade IV isthmic spondylolisthesis undergoes posterior spinal fusion with instrumental reduction. Postoperatively, she is noted to have a new foot drop and weakness in great toe extension. Injury to which of the following structures is the most likely cause?

Explanation

The L5 nerve root is at the greatest risk of iatrogenic injury during the reduction of high-grade L5-S1 spondylolisthesis. The mechanism is a stretch neuropraxia as the L5 root is pulled taut over the sacral ala during the posterior and cranial translation of the L5 vertebra.

Question 29

A 55-year-old woman with a 20-year history of severe rheumatoid arthritis complains of neck pain, occipital headache, and subjective bilateral hand clumsiness. Which of the following radiographic measurements is most indicative of basilar invagination (cranial settling) in this patient?

Explanation

A Ranawat value (the perpendicular distance from the center of the C2 pedicles to the transverse axis of C1) of less than 13 mm indicates basilar invagination, also known as cranial settling. ADI and PADI are used to assess atlantoaxial instability, not basilar invagination.

Question 30

A 16-year-old gymnast presents with 3 weeks of focal lower back pain exacerbated by extension. Plain radiographs of the lumbar spine are normal. What is the most appropriate next imaging modality to diagnose an acute pars interarticularis stress reaction while minimizing radiation exposure?

Explanation

MRI of the lumbar spine with short tau inversion recovery (STIR) or T2 fat-suppressed sequences is the modality of choice for detecting acute pars stress reactions (edema) in adolescents. It provides high sensitivity for acute lesions without the ionizing radiation associated with CT or SPECT scans.

Question 31

A neurologically intact 40-year-old male sustains an L1 burst fracture after a fall. MRI confirms that the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score and the recommended management?

Explanation

The TLICS assigns 2 points for a burst fracture morphology, 0 points for an intact PLC, and 0 points for intact neurologic status. A total score of 3 or less indicates non-operative management is recommended.

Question 32

An 84-year-old female presents with a Type II odontoid fracture with 3 mm of posterior displacement following a low-energy ground-level fall. She is neurologically intact. Which of the following management strategies is generally contraindicated in this specific demographic due to high associated morbidity and mortality?

Explanation

Halo vest immobilization in the elderly (over 80 years old) is associated with an unacceptably high risk of severe complications, including pneumonia, cardiac arrest, and death. Management typically involves either a rigid cervical collar or posterior surgical fusion if operative intervention is indicated.

Question 33

A 14-year-old female with Adolescent Idiopathic Scoliosis (AIS) has a main thoracic curve of 55 degrees, a proximal thoracic curve of 30 degrees that bends out to 15 degrees, and a thoracolumbar curve of 40 degrees that bends out to 20 degrees. The apical lumbar vertebra is bisected by the center sacral vertical line (CSVL). The T5-T12 sagittal kyphosis is 25 degrees. What is her Lenke classification?

Explanation

The main thoracic curve is the major curve, and both minor curves bend out to < 25 degrees, making it a Type 1 (Main Thoracic). The CSVL bisecting the apical lumbar vertebra makes it a lumbar modifier B. Normal sagittal kyphosis (10 to 40 degrees) gives a sagittal modifier N, resulting in 1BN.

Question 34

A 55-year-old Asian male presents with severe cervical myelopathy. Imaging reveals continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. The K-line, drawn from the midpoints of the spinal canal at C2 and C7 on a neutral lateral radiograph, does not cross the peak of the OPLL (K-line negative). What is the significance of this finding regarding surgical planning?

Explanation

A negative K-line indicates that the kyphotic alignment or massive OPLL will prevent the spinal cord from adequately drifting posteriorly following a posterior decompression. Therefore, laminoplasty alone is associated with poor outcomes, and anterior decompression or posterior decompression with instrumented fusion is preferred.

Question 35

A 60-year-old diabetic male presents with a 3-day history of escalating lower back pain, fever, bilateral lower extremity weakness (grade 3/5), and new-onset urinary retention. MRI reveals a ventral epidural abscess spanning L2 to L4 with severe cauda equina compression. What is the most appropriate next step in management?

Explanation

The patient presents with progressive neurologic deficits and signs of cauda equina syndrome secondary to an epidural abscess. Emergent surgical decompression and debridement are required to prevent permanent neurological damage, alongside targeted intravenous antibiotics.

Question 36

When evaluating a patient with a spinal metastatic lesion, the Spinal Instability Neoplastic Score (SINS) is utilized to assess the need for surgical stabilization. Which of the following radiographic or clinical findings contributes the highest point value (4 points) to the SINS calculation?

Explanation

In the SINS criteria, the presence of subluxation or translation on spinal alignment yields the maximum possible points (4 points) for that category, heavily indicating instability. Mechanical pain contributes 3 points, while lytic lesions contribute 2 points.

Question 37

A 16-year-old gymnast is diagnosed with a Grade III L5-S1 isthmic spondylolisthesis. If the patient develops radicular symptoms secondary to the pars defect and hypertrophic fibrocartilaginous tissue in the neural foramen, which nerve root is most commonly affected?

Explanation

In isthmic spondylolisthesis at L5-S1, the exiting L5 nerve root is most commonly compressed within the neural foramen by the pars defect fibrocartilaginous mass or by traction over the sacral ala. The traversing S1 root is typically affected in disc herniations at this level, not the isthmic defect itself.

Question 38

A 45-year-old male presents to the emergency department with acute lower back pain and bilateral leg numbness. The resident suspects Cauda Equina Syndrome (CES). Which of the following clinical findings has the highest positive predictive value for confirming CES requiring urgent surgical decompression?

Explanation

Urinary retention leading to overflow incontinence (often documented by a post-void residual > 500 mL) has the highest sensitivity and positive predictive value for diagnosing true Cauda Equina Syndrome. Early recognition and decompression are critical for functional recovery.

Question 39

According to the Spine Patient Outcomes Research Trial (SPORT) evaluating the treatment of degenerative spondylolisthesis with spinal stenosis, what was the primary conclusion comparing surgical to non-operative management at the 4-year follow-up?

Explanation

The SPORT study on degenerative spondylolisthesis demonstrated that patients treated surgically (decompression and fusion) had significantly greater improvements in pain and function at 4 years compared to those treated non-operatively, despite the high rate of crossover.

Question 40

A 15-year-old male presents with postural deformity. Radiographs reveal a thoracic kyphosis of 75 degrees. To officially diagnose Scheuermann's kyphosis using Sorensen's criteria, the lateral radiograph must demonstrate which of the following?

Explanation

Sorensen's criteria define classic Scheuermann's kyphosis as thoracic kyphosis > 40 degrees with anterior wedging of 5 degrees or more in at least three consecutive vertebrae. Associated findings often include Schmorl's nodes and endplate irregularities.

Question 41

A 50-year-old male with a known history of advanced ankylosing spondylitis presents to the emergency department with severe neck pain after a minor low-speed motor vehicle collision. Standard anteroposterior and lateral cervical radiographs show no obvious fracture. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at extremely high risk for highly unstable, occult fractures even after minor trauma. Standard radiographs are notoriously inadequate due to altered bony anatomy; therefore, a high-resolution CT scan of the entire cervical spine is mandatory.

Question 42

When placing a standard anatomic lumbar pedicle screw at the L4 level, what is the most widely accepted surface landmark for the starting point?

Explanation

The anatomic starting point for a lumbar pedicle screw is located at the intersection of a horizontal line bisecting the transverse process and a vertical line plumb with the lateral border of the superior articular process (facet joint).

Question 43

An adult patient with sagittal imbalance is scheduled for spinal deformity correction. The measured Pelvic Incidence (PI) is 60 degrees. According to the SRS-Schwab adult spinal deformity classification, which of the following is the target Lumbar Lordosis (LL) to minimize the risk of mechanical failure and adjacent segment disease?

Explanation

The SRS-Schwab classification emphasizes matching Lumbar Lordosis (LL) to Pelvic Incidence (PI) to achieve sagittal harmony. The target for PI-LL mismatch is strictly within +/- 9 degrees, meaning the ideal LL for a PI of 60 degrees is approximately 60 degrees.

Question 44

A 45-year-old male presents with severe radicular leg pain. MRI demonstrates a large, exclusively extraforaminal (far lateral) disc herniation at the L4-L5 level. Which nerve root is most likely compressed by this specific pathology?

Explanation

In a far lateral (extraforaminal) disc herniation, the exiting nerve root at that level is compressed. At L4-L5, the L4 nerve root exits the foramen and travels laterally, making it the root affected by a far lateral herniation.

Question 45

A patient presents with neck pain radiating down the arm. Neurologic examination reveals a diminished triceps reflex, weakness in elbow extension and wrist flexion, and altered sensation over the dorsal middle finger. Which cervical nerve root is most likely compressed?

Explanation

Compression of the C7 nerve root classically presents with a diminished triceps reflex, weakness in the triceps (elbow extension) and wrist flexors, and numbness/tingling radiating to the middle finger.

Question 46

A 35-year-old male presents after falling from a 10-foot roof. He is neurologically intact. CT of the lumbar spine demonstrates an L1 burst fracture with 30% canal compromise. MRI confirms an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

Explanation

This patient has a TLICS score of 2 (Burst morphology = 2, Neurologically intact = 0, PLC intact = 0). A TLICS score of 3 or less is an indication for non-operative management, typically with a rigid TLSO.

Question 47

A 68-year-old male with long-standing ankylosing spondylitis presents with severe neck pain after a minor fall. Initial plain radiographs are difficult to interpret due to extensive ossification. Neurological examination reveals rapidly progressive quadriparesis. What is the most likely etiology of his acute neurological decline?

Explanation

Patients with ankylosing spondylitis who sustain cervical fractures are at high risk for spinal epidural hematomas due to bleeding from fractured ossified epidural vessels and the altered biomechanics of the ankylosed spine. Emergent MRI is indicated to evaluate for hematoma requiring decompression.

Question 48

An 82-year-old female presents with neck pain following a ground-level fall. Imaging reveals a Type II odontoid fracture with 6 mm of posterior displacement. She is neurologically intact but has significant medical comorbidities. Which of the following factors is the strongest predictor of nonunion if this patient is managed conservatively with a hard collar?

Explanation

In Type II odontoid fractures, an initial displacement of greater than 5 mm and age greater than 50 years are the most significant risk factors for nonunion. Consequently, surgical stabilization is often favored in these patients despite advanced age, provided they can tolerate surgery.

Question 49

A 55-year-old male with poorly controlled diabetes presents with severe back pain, fevers, and acute bilateral lower extremity weakness. MRI reveals a ventral spinal epidural abscess spanning L2-L4 with severe thecal sac compression. Blood cultures are pending. What is the most appropriate next step in management?

Explanation

Neurologic deficit in the setting of a spinal epidural abscess is an absolute indication for emergent surgical decompression and debridement. Conservative management with antibiotics alone is reserved for neurologically intact patients or those medically unfit for surgery.

Question 50

In a patient with rheumatoid arthritis presenting with cervical myelopathy due to atlantoaxial subluxation, which of the following radiographic parameters is the most reliable predictor of postoperative neurologic recovery?

Explanation

The Posterior Atlantodental Interval (PADI) represents the actual space available for the spinal cord. A PADI of less than 14 mm is associated with a higher risk of neurologic deficit, and a PADI of less than 10 mm indicates a poor prognosis for neurologic recovery after surgery.

Question 51

A 25-year-old male is brought to the emergency department after a motor vehicle collision. He is awake, alert, and fully cooperative. Neurological examination is completely normal (ASIA E). Cervical spine radiographs reveal a bilateral facet dislocation at C5-C6. What is the most appropriate next step in management?

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation, rapid closed reduction via cranial traction is the recommended initial step to restore alignment and decompress the canal. An MRI before reduction is indicated if the patient has an altered mental status or is unexaminable.

Question 52

During a posterior spinal fusion for adolescent idiopathic scoliosis, the neuromonitoring technician reports a sudden bilateral loss of motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs). The surgeon halts the correction maneuver. What is the most appropriate initial action by the anesthesia team?

Explanation

A sudden loss of bilateral evoked potentials suggests global spinal cord ischemia or severe compression. The immediate management includes halting the surgical maneuver, increasing MAP to >85 mmHg to optimize spinal cord perfusion, and verifying hemoglobin and oxygenation.

Question 53

A 16-year-old male presents with thoracic back pain and a rigid kyphotic deformity. Lateral radiographs demonstrate anterior wedging of the T7, T8, and T9 vertebral bodies. What is the minimum degree of wedging required in each of these adjacent vertebrae to confirm the diagnosis of classic Scheuermann's disease?

Explanation

The Sorensen criteria for classic Scheuermann's kyphosis require anterior wedging of greater than 5 degrees in at least three consecutive vertebrae. It is also associated with irregular endplates and Schmorl's nodes.

Question 54

A 12-year-old female presents with a high-grade (Meyerding Grade IV) L5-S1 isthmic spondylolisthesis. She has severe hamstring tightness and an abnormal gait, but is neurologically intact. During surgical intervention, an attempt is made to fully reduce the spondylolisthesis prior to fusion. Which nerve root is at the greatest risk of injury during this reduction maneuver?

Explanation

Reduction of high-grade L5-S1 spondylolisthesis places the L5 nerve root at significant risk of traction injury as it stretches over the sacral ala. Partial reduction or in situ fusion is often utilized to minimize this risk.

Question 55

A 60-year-old male with a history of renal cell carcinoma presents with progressive paraparesis and a sensory level at T10. MRI reveals a metastatic lesion at T9 with severe spinal cord compression. His estimated life expectancy is 12 months. Which of the following is the most appropriate management strategy?

Explanation

Renal cell carcinoma is a radioresistant tumor. In a patient with mechanical instability or epidural spinal cord compression from a radioresistant metastasis and a life expectancy >6 months, surgical decompression (separation surgery) followed by stereotactic radiosurgery (SRS) is the gold standard.

Question 56

An adult patient with severe sagittal imbalance secondary to flatback syndrome is evaluated for corrective surgery. On standing lateral radiographs, the patient's lumbar lordosis is significantly reduced. What is the primary pelvic compensatory mechanism the patient will use to maintain an upright posture and keep their gaze horizontal?

Explanation

In the setting of a loss of lumbar lordosis (sagittal positive imbalance), the body compensates by rotating the pelvis posteriorly (pelvic retroversion), which radiographically presents as an increased Pelvic Tilt (PT) and a decreased Sacral Slope (SS). Pelvic Incidence (PI) remains constant.

Question 57

A 30-year-old male sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following a motor vehicle accident. Radiographs reveal marked angulation of C2 on C3 with minimal translation. This is classified as a Levine-Edwards Type IIA fracture. Which of the following treatments is absolutely contraindicated?

Explanation

A Type IIA Hangman's fracture features severe angulation with minimal translation due to complete disruption of the C2-C3 intervertebral disc and the anterior longitudinal ligament. Application of cervical traction is contraindicated as it will further distract the fracture and increase the deformity.

Question 58

A 45-year-old male with a history of intravenous drug use presents with severe back pain. Laboratory tests show elevated ESR and CRP. MRI with contrast reveals signal changes and enhancement of the L3-L4 disc space consistent with discitis/osteomyelitis. Blood cultures are negative. What is the most appropriate next step prior to initiating antibiotic therapy?

Explanation

In cases of spontaneous pyogenic discitis/osteomyelitis with negative blood cultures and no neurologic deficit or instability, a CT-guided percutaneous biopsy should be performed to isolate the causative organism before initiating empiric antibiotics.

Question 59

A 55-year-old male of Asian descent presents with progressive clumsiness in his hands and broad-based gait. Cervical spine MRI shows severe multi-level ventral cord compression secondary to Ossification of the Posterior Longitudinal Ligament (OPLL). A lateral cervical radiograph demonstrates that the OPLL mass crosses the K-line (a "K-line negative" cervical spine). What is the surgical implication of this finding?

Explanation

A K-line connects the mid-canal of C2 to C7. If the OPLL mass exceeds the K-line (K-line negative), the cervical alignment is typically kyphotic or the mass is massive, meaning the cord will not drift posteriorly after a laminectomy/laminoplasty. An anterior or combined approach is necessary.

Question 60

A 22-year-old male restrained rear-seat passenger is involved in a head-on collision. He presents with severe thoracolumbar back pain. CT of the spine reveals a T12 flexion-distraction injury (Chance fracture) extending through the pedicles and posterior elements. Which of the following injuries is most highly associated with this specific fracture pattern?

Explanation

Chance fractures (flexion-distraction injuries) are frequently caused by lap seatbelts acting as a fulcrum during rapid deceleration. They have a high association (up to 40-50%) with intra-abdominal hollow viscus injuries, such as bowel perforations.

Question 61

A 55-year-old male undergoes an uncomplicated 8-hour posterior instrumented lumbar fusion for adult degenerative scoliosis in the prone position. He experiences a 1.5 L estimated blood loss. On postoperative day 1, he complains of painless, bilateral visual loss. Pupillary reflexes are sluggish. What is the most likely etiology?

Explanation

Ischemic optic neuropathy (ION) is the most common cause of postoperative visual loss following long-duration spine surgeries in the prone position. Risk factors include prolonged operative time, significant blood loss, hypotension, and the use of a Wilson frame (head lower than the heart).

Question 62

A 45-year-old female presents with persistent, severe axial neck pain one year after an anterior cervical discectomy and fusion (ACDF) at C5-C7. Flexion-extension radiographs and a thin-cut CT scan demonstrate a clear pseudarthrosis at the C6-C7 level with loosening of the anterior hardware. She is neurologically intact. What is the most reliable surgical option to achieve solid fusion in this patient?

Explanation

For a symptomatic pseudarthrosis following an initial anterior cervical fusion, a posterior cervical instrumented fusion offers the highest union rate (near 100%) and is considered the rescue procedure of choice, avoiding the scarred anterior approach.

Question 63

A 70-year-old male presents with bilateral lower extremity pain and cramping that worsens with walking and prolonged standing, but improves when he leans forward over a shopping cart. Examination reveals normal peripheral pulses. In differentiating this condition from vascular claudication, which of the following activities is classically better tolerated by this patient?

Explanation

This patient has neurogenic claudication secondary to lumbar spinal stenosis. Lumbar flexion increases the cross-sectional area of the spinal canal, relieving symptoms. Thus, walking uphill (which induces slight lumbar flexion) is classically better tolerated than walking downhill (which induces extension).

Question 64

An 8-year-old female presents with a 2-week history of torticollis and neck pain following a severe upper respiratory tract infection. Radiographs are consistent with atlantoaxial rotatory subluxation (Grisel's syndrome). Neurologic examination is normal. What is the most appropriate initial management?

Explanation

Grisel's syndrome is a non-traumatic atlantoaxial rotatory subluxation often secondary to local inflammation from a head/neck infection. For subluxation present for less than one month, initial management typically involves cervical halter traction, muscle relaxants, and anti-inflammatories, followed by bracing.

Question 65

A 40-year-old male presents with low back pain and unilateral radicular pain in the right S1 distribution. He undergoes a right L5-S1 microdiscectomy. Postoperatively, his radicular pain is completely resolved, but three weeks later, he develops excruciating, recurrent right leg pain. MRI with gadolinium shows a rim-enhancing fluid collection in the epidural space at the operative site. What is the most likely diagnosis?

Explanation

A rim-enhancing fluid collection in the epidural space on a contrast-enhanced MRI in the early postoperative period, accompanied by severe recurrent symptoms, is highly suggestive of a postoperative epidural abscess. A recurrent disc herniation would typically show central, not rim, enhancement, while epidural fibrosis enhances uniformly.

Question 66

A 72-year-old male presents with a Type II odontoid fracture following a ground-level fall. He is being considered for nonoperative management in a hard cervical collar. Which of the following fracture characteristics is most strongly associated with an increased risk of nonunion in this scenario?

Explanation

Risk factors for nonunion of Type II odontoid fractures include initial displacement > 5 mm, angulation > 10 degrees, age > 65 years, and delayed treatment. Displacement > 5 mm significantly decreases the vascularity and cortical contact needed for healing.

Question 67

A 45-year-old male presents after a motor vehicle accident with an L1 burst fracture. Neurological examination is completely normal. CT and MRI show a burst fracture with retropulsion, intact posterior ligamentous complex, and no epidural hematoma. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended management?

Explanation

The TLICS score for this patient is 2: morphology is burst (2 points), neurological status is intact (0 points), and the posterior ligamentous complex is intact (0 points). A score of 3 or less is a strong indication for nonoperative management.

Question 68

A 70-year-old male with a known history of Diffuse Idiopathic Skeletal Hyperostosis (DISH) presents with severe back pain after a minor fall. Initial plain radiographs of the spine appear largely unchanged from prior exams, showing flowing anterior osteophytes. What is the most appropriate next step in management?

Explanation

Patients with DISH have rigid spines and are highly susceptible to highly unstable, shear-type fractures even from minor trauma, which may be occult on plain radiographs. A whole-spine CT or MRI is mandatory to rule out fractures and prevent catastrophic delayed neurologic deterioration.

Question 69

A 45-year-old male presents with right leg pain, numbness over the dorsum of the foot, and weakness in great toe extension. MRI reveals a right-sided far-lateral (extraforaminal) disc herniation at L4-L5. Which nerve root is most likely compressed?

Explanation

In the lumbar spine, a far-lateral (extraforaminal) disc herniation compresses the exiting nerve root at that specific level. Therefore, an L4-L5 far-lateral herniation affects the exiting L4 nerve root, whereas a standard paracentral herniation would affect the traversing L5 root.

Question 70

A 55-year-old male with progressive gait clumsiness is diagnosed with cervical myelopathy secondary to Ossification of the Posterior Longitudinal Ligament (OPLL). The 'K-line' on his cervical lateral radiograph is plotted, and the OPLL mass crosses anterior to the K-line (K-line negative). Which surgical approach is most biomechanically appropriate?

Explanation

A 'K-line negative' cervical spine indicates that the OPLL mass exceeds the kyphotic alignment or is too large, meaning the spinal cord will not sufficiently drift backward after a posterior-only decompression. An anterior approach (e.g., corpectomy) or combined anterior-posterior approach is indicated to adequately decompress the cord.

Question 71

A 60-year-old diabetic patient presents with back pain, fever, and new-onset bowel and bladder incontinence. MRI reveals a large lumbar spinal epidural abscess with severe thecal sac compression. He is hemodynamically stable. What is the most appropriate next step in management?

Explanation

The presence of a spinal epidural abscess combined with acute neurological deficits, such as cauda equina syndrome, is an absolute indication for emergent surgical decompression and debridement to maximize the chance of neurological recovery.

Question 72

A 45-year-old male with long-standing Ankylosing Spondylitis sustains an extension-distraction injury of the cervical spine through the C5-C6 disc space. Upon arrival, he is neurologically intact, but 4 hours later he develops progressive quadriplegia. What is the most likely cause of his neurological deterioration?

Explanation

Patients with ankylosing spondylitis who sustain spinal fractures are at a exceptionally high risk for epidural hematomas due to bleeding from fractured epidural veins and rigid, vascularized bone. Progressive neurological deterioration after a lucid interval is classic for an expanding epidural hematoma.

Question 73

In the evaluation of Adolescent Idiopathic Scoliosis (AIS), dynamic side-bending radiographs are routinely obtained. According to the Lenke classification, a curve is defined as 'structural' if it has a residual Cobb angle of at least what magnitude on maximal side-bending?

Explanation

The Lenke classification of AIS dictates that a minor curve is considered structurally significant if it does not bend out to less than 25 degrees (i.e., residual Cobb angle is >/= 25 degrees) on dynamic side-bending radiographs or has a kyphosis >/= +20 degrees.

Question 74

A 15-year-old male presents with cosmetic concerns regarding a rounded upper back. Lateral thoracic spine radiographs demonstrate a thoracic kyphosis of 55 degrees. To meet the strict radiographic criteria for Sorensen's definition of Scheuermann's disease, there must be anterior wedging of at least 5 degrees in how many consecutive vertebrae?

Explanation

Sorensen's criteria for the diagnosis of classic Scheuermann's kyphosis require the presence of a regional thoracic kyphosis > 40 degrees and anterior wedging of >/= 5 degrees in at least three consecutive vertebrae.

Question 75

A 60-year-old female with metastatic renal cell carcinoma presents with mechanical back pain and an isolated L2 vertebral body metastasis. Neurological exam is intact, and MRI shows no epidural spinal cord compression. However, CT reveals bilateral pedicle destruction and 60% loss of vertebral body height. According to the NOMS framework, what is the most appropriate primary treatment strategy?

Explanation

The NOMS framework assesses Neurologic, Oncologic, Mechanical, and Systemic factors. Bilateral pedicle destruction and significant height loss indicate severe mechanical instability, which requires surgical stabilization prior to radiation therapy (SBRT is preferred here for radioresistant renal cell tumors).

Question 76

A 24-year-old male presents after a high-speed motor vehicle collision. CT of the cervical spine shows a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation, 5 mm of translation, and bilateral C2-C3 facet dislocations. Based on the Levine-Edwards classification, what is the injury type and optimal treatment?

Explanation

A Levine-Edwards Type III Hangman's fracture is characterized by pars interarticularis fractures accompanied by unilateral or bilateral C2-C3 facet dislocations. This is a highly unstable injury that cannot be managed non-operatively or with traction, necessitating urgent open reduction and internal fixation.

Orthopedic Spine Review | Dr Hutaif Spine Surgery Revie -...

Orthopedic Board Review MCQs: Spine Surgery Questions | Part 27

Key Takeaway

Orthopedic Board Review MCQs: Spine Surgery Questions | Part 27

Chapter Index