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6. Spine MCQs

Practice Set 248 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 4941

Topic: 6. Spine

A 62-year-old woman presents with a 1-year history of neurogenic claudication and low back pain. Flexion-extension radiographs demonstrate a dynamic L4-L5 degenerative spondylolisthesis with 4 mm of translation. MRI confirms severe central canal stenosis at L4-L5. She has failed 6 months of nonoperative management. Based on classic randomized controlled trials, which of the following surgical interventions has historically demonstrated the most reliable long-term outcomes for this condition?

. L4-L5 isolated decompression (laminectomy)
. L4-L5 laminectomy with instrumented posterolateral fusion
. L4-L5 anterior lumbar interbody fusion (ALIF) alone
. Interspinous process spacer placement
. Translaminar screw fixation without decompression

Correct Answer & Explanation

. L4-L5 laminectomy with instrumented posterolateral fusion

Explanation

The SPORT trial (Spine Patient Outcomes Research Trial) and other classic studies have traditionally supported laminectomy with instrumented fusion over decompression alone for patients with degenerative spondylolisthesis and spinal stenosis, due to a lower risk of progression of the slip and need for reoperation. For a patient with documented dynamic instability (4 mm of translation on flexion-extension), laminectomy with instrumented posterolateral fusion remains the gold standard to achieve both neural decompression and segmental stability.

Question 4942

Topic: 6. Spine

A 15-year-old male gymnast presents with persistent low back pain that is worsened by spinal extension. Oblique radiographs demonstrate a "Scottie dog with a collar" sign at L5. MRI shows increased signal in the pars interarticularis on STIR sequences but no obvious gap on T1. What is the most appropriate initial management?

. L5-S1 instrumented fusion
. Direct pars repair
. Physical therapy focusing on core strengthening and an anti-lordotic brace
. Epidural steroid injection
. Diagnostic pars block

Correct Answer & Explanation

. Physical therapy focusing on core strengthening and an anti-lordotic brace

Explanation

The patient has an acute or stress-reactive spondylolysis, indicated by the increased STIR signal on MRI without a definite fracture gap (which would be more typical of a chronic nonunion). The most appropriate initial management for an acute symptomatic spondylolysis is activity modification, core strengthening, and often the use of an anti-lordotic (Boston-style) brace to limit extension. Surgery is reserved for patients who fail prolonged nonoperative management (usually at least 6 months) or those with progressive spondylolisthesis and neurological symptoms.

Question 4943

Topic: 6. Spine

A 45-year-old man with a long-standing history of ankylosing spondylitis presents to the emergency department after a low-speed motor vehicle collision. He complains of severe lower neck pain. Neurological examination is normal. Standard anteroposterior and lateral cervical spine radiographs are interpreted as negative. What is the most appropriate next step in management?

. Discharge with a soft cervical collar and NSAIDs
. Perform dynamic flexion-extension radiographs
. Obtain a CT scan of the cervical spine
. Obtain an MRI of the brain
. Reassure the patient and prescribe physical therapy

Correct Answer & Explanation

. Obtain a CT scan of the cervical spine

Explanation

Patients with ankylosing spondylitis have a highly rigid, osteopenic spine that acts as long bone. It is extremely susceptible to fractures even from minor trauma. These fractures are often highly unstable, involve all three columns, and can be easily missed on standard radiographs due to altered anatomy, osteopenia, and superimposition of the shoulders. Therefore, any patient with ankylosing spondylitis presenting with neck or back pain after trauma must undergo a CT scan of the entire involved spinal region to rule out a fracture. Flexion-extension radiographs are strictly contraindicated due to the high risk of catastrophic neurological injury in the presence of an occult unstable fracture.

Question 4944

Topic: 6. Spine

A 54-year-old diabetic man presents with a 1-week history of severe mid-back pain, low-grade fevers, and new-onset urinary retention. Examination reveals bilateral lower extremity weakness (motor strength 3/5) and decreased sensation below the T8 dermatome. MRI with gadolinium demonstrates a dorsal epidural collection spanning T6 to T9 with peripheral rim enhancement, severely compressing the spinal cord. What is the most appropriate definitive management?

. Intravenous antibiotics and close neurological observation
. CT-guided aspiration and intravenous antibiotics
. Emergent posterior decompressive laminectomy and debridement
. Anterior corpectomy and strut grafting
. Placement of a lumbar drain

Correct Answer & Explanation

. Emergent posterior decompressive laminectomy and debridement

Explanation

The patient is presenting with a spinal epidural abscess complicated by an acute, progressive neurological deficit (myelopathy and neurogenic bladder). In the setting of a spinal epidural abscess with progressive or acute neurological compromise, emergent surgical decompression (via posterior laminectomy for a dorsal abscess) and debridement is the standard of care. Nonoperative management with IV antibiotics is generally reserved for patients who are neurologically intact, extremely poor surgical candidates, or have pan-spinal epidural abscesses without focal cord compression.

Question 4945

Topic: 6. Spine

A 42-year-old woman presents with acute onset of severe low back pain, bilateral sciatica, and perineal numbness. She reports one episode of urinary incontinence earlier in the day. Post-void residual (PVR) volume is 400 mL. MRI reveals a massive L4-L5 central disc herniation filling the spinal canal. Which of the following is the most critical prognostic factor for full recovery of her bladder function?

. The size of the disc herniation on MRI
. The time from the onset of urinary dysfunction to surgical decompression
. The degree of leg pain at presentation
. The patient's age and baseline BMI
. The use of high-dose intravenous steroids prior to surgery

Correct Answer & Explanation

. The time from the onset of urinary dysfunction to surgical decompression

Explanation

In cauda equina syndrome (CES), the most important prognostic factor for the recovery of neurological function, particularly bladder and bowel function, is the timing of surgical decompression. Decompression within 24 to 48 hours of the onset of autonomic (bladder/bowel) dysfunction or perineal numbness is generally recommended to maximize the chance of full recovery. The presence of urinary incontinence with a high post-void residual indicates CES with retention (CES-R), which typically has a poorer prognosis than incomplete CES (CES-I), making urgent surgical decompression the absolute priority.

Question 4946

Topic: 6. Spine

A 60-year-old man with a history of prostate cancer presents with progressive mechanical back pain.

Imaging shows a metastatic lesion at L2 involving the vertebral body and the left pedicle. The Spine Instability Neoplastic Score (SINS) is calculated to be 14. He has no neurological deficits. Based on this score, what is the most appropriate recommendation regarding his spinal stability?

. The spine is stable; proceed with radiation therapy alone
. The spine is potentially unstable; bracing is the definitive treatment
. The spine is unstable; surgical consultation for stabilization is indicated prior to radiation
. The spine is stable; bisphosphonate therapy is sufficient
. The spine is unstable; isolated kyphoplasty should be performed

Correct Answer & Explanation

. The spine is unstable; surgical consultation for stabilization is indicated prior to radiation

Explanation

The Spine Instability Neoplastic Score (SINS) evaluates six components: location, pain, bone lesion type, radiographic alignment, vertebral body collapse, and posterolateral involvement. A score of 0-6 indicates stability, 7-12 indicates potential instability, and 13-18 indicates instability. A SINS of 14 falls into the unstable category. Therefore, the patient should be referred for surgical consultation for stabilization before undergoing radiation therapy. Radiation alone on an unstable spine may lead to progressive collapse and secondary neurological compromise.

Question 4947

Topic: 6. Spine

A 55-year-old woman with a 20-year history of severe rheumatoid arthritis presents with neck pain and paresthesias in her hands. Flexion-extension radiographs of the cervical spine demonstrate an anterior atlanto-dens interval (ADI) of 11 mm. What is the most appropriate management?

. Continued observation with annual radiographs
. Application of a hard cervical collar
. Posterior C1-C2 fusion
. Transoral odontoidectomy without fusion
. Administration of a biologic DMARD and physical therapy

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

In rheumatoid arthritis, atlantoaxial subluxation is a serious complication. An anterior atlanto-dens interval (ADI) greater than 3 mm is abnormal in adults. An ADI > 9-10 mm indicates disruption of all supporting ligamentous structures (transverse, alar, and apical ligaments) and places the patient at a high risk for neurologic injury, as the space available for the cord is significantly compromised. In the presence of an ADI of 11 mm and neurologic symptoms (paresthesias), surgical stabilization—typically a posterior C1-C2 fusion—is firmly indicated to prevent progressive myelopathy or sudden death.

Question 4948

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with severe mechanical back pain and difficulty standing upright. Radiographs reveal a pelvic incidence (PI) of 65°, lumbar lordosis (LL) of 30°, pelvic tilt (PT) of 35°, and a sagittal vertical axis (SVA) of +12 cm. She has failed extensive nonoperative management. If surgical correction is planned, what is the primary sagittal alignment goal to optimize her clinical outcome?

. Decrease pelvic tilt to 0°
. Restore lumbar lordosis to within 10° of her pelvic incidence
. Reduce the SVA to less than 10 cm
. Increase thoracic kyphosis to match the pelvic incidence
. Match the lumbar lordosis to the pelvic tilt

Correct Answer & Explanation

. Restore lumbar lordosis to within 10° of her pelvic incidence

Explanation

In adult spinal deformity, restoring sagittal balance is highly correlated with improved clinical outcomes (e.g., ODI scores). The key parameters include a sagittal vertical axis (SVA) < 5 cm, a pelvic tilt (PT) < 20°, and a mismatch between pelvic incidence (PI) and lumbar lordosis (LL) of < 10° (PI - LL < 10°). Because PI is a fixed anatomic parameter, the surgical goal is to increase LL to closely match the PI.

Question 4949

Topic: 6. Spine

A 72-year-old man with long-standing ankylosing spondylitis presents to the emergency department after a low-energy ground-level fall. He complains of severe neck pain but has no neurologic deficits. Initial plain radiographs of the cervical spine are obscured by his severe cervicothoracic kyphosis. What is the most appropriate next step in management?

. Discharge with a hard cervical collar and outpatient follow-up
. Flexion-extension cervical spine radiographs
. Computed tomography (CT) of the entire cervical and thoracic spine
. Intravenous methylprednisolone
. Immediate halo vest immobilization

Correct Answer & Explanation

. Computed tomography (CT) of the entire cervical and thoracic spine

Explanation

Patients with ankylosing spondylitis are at a high risk for highly unstable, often unrecognized, spinal fractures even after low-energy trauma. The fused spine acts as a long, brittle bone. Because plain radiographs are frequently difficult to interpret due to deformity and osteopenia, a CT scan of the spine is the diagnostic modality of choice to evaluate for fracture. These fractures are often 3-column injuries and carry a high risk of neurologic injury or epidural hematoma.

Question 4950

Topic: 6. Spine

A 55-year-old woman presents with progressive leg weakness, numbness in her perineal region, and recent onset of urinary incontinence. She reports an acute exacerbation of lower back pain after lifting a heavy box. Post-void residual (PVR) bladder volume is 400 mL. MRI reveals a massive L4-L5 central disc herniation. Which of the following is the most significant prognostic factor for recovery of normal bladder function following emergency surgical decompression?

. The specific surgical approach used (e.g., minimally invasive vs. open)
. Preoperative administration of intravenous steroids
. The patient's age and body mass index
. The presence of bilateral versus unilateral leg pain
. The duration of autonomic (sphincter) dysfunction prior to decompression

Correct Answer & Explanation

. The duration of autonomic (sphincter) dysfunction prior to decompression

Explanation

The clinical presentation is consistent with Cauda Equina Syndrome (CES), a surgical emergency. The most significant prognostic factor for the recovery of neurologic and bladder/bowel function is the duration of symptoms (specifically autonomic/sphincter dysfunction) prior to surgical decompression. Decompression within 24 to 48 hours of symptom onset is generally associated with the most favorable outcomes.

Question 4951

Topic: Thoracolumbar Spine & Deformity

A 32-year-old construction worker falls from a height of 10 feet and sustains an isolated L1 burst fracture. He is neurologically intact. Upright radiographs demonstrate 15° of regional kyphosis and 30% loss of anterior vertebral body height. CT scan shows retropulsion of the posterosuperior vertebral body fragment occluding 25% of the spinal canal. The posterior ligamentous complex (PLC) is intact on MRI. According to the Thoracolumbar Injury Classification and Severity (TLICS) system, what is his total score and the recommended treatment pathway?

. TLICS score 2; nonoperative management
. TLICS score 4; operative management
. TLICS score 4; surgeon's choice of operative or nonoperative management
. TLICS score 5; operative management
. TLICS score 6; operative management

Correct Answer & Explanation

. TLICS score 2; nonoperative management

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) score evaluates injury morphology, integrity of the posterior ligamentous complex (PLC), and neurologic status. For this patient: Morphology is a burst fracture (2 points); PLC is intact (0 points); Neurologic status is intact (0 points). The total TLICS score is 2. A score of 3 or less indicates nonoperative management. A score of 4 can be treated operatively or nonoperatively (surgeon's choice), and a score of 5 or more dictates operative stabilization.

Question 4952

Topic: 6. Spine



A 60-year-old man presents with neurogenic claudication. Figure 32 shows an imaging study demonstrating degenerative spondylolisthesis at L4-L5. Based on the Spine Patient Outcomes Research Trial (SPORT) for degenerative spondylolisthesis, patients treated surgically with decompression and fusion compared to those treated nonoperatively demonstrated:

. No significant difference in long-term outcomes
. Significantly improved pain and function at 4 years, analyzed by intention-to-treat
. Significantly improved pain and function at 4 years, analyzed by as-treated analysis
. Higher rates of neurologic complications and worse clinical outcomes
. Similar initial outcomes, but nonoperative patients had better 10-year survival

Correct Answer & Explanation

. Significantly improved pain and function at 4 years, analyzed by as-treated analysis

Explanation

The SPORT trial for degenerative spondylolisthesis found that patients treated surgically had significantly improved pain and function. However, due to very high rates of crossover between the two randomized groups, the pure intention-to-treat analysis failed to show a statistically significant difference. When evaluated by the 'as-treated' method (analyzing patients based on the treatment they actually received), surgical intervention showed a highly significant and sustained advantage in pain relief, functional recovery, and patient satisfaction over nonoperative treatment.

Question 4953

Topic: 6. Spine

A 40-year-old woman undergoes a posterior cervical foraminotomy for a C5-C6 soft disc herniation causing C6 radiculopathy. Postoperatively, she develops new-onset weakness in her ipsilateral deltoid and biceps (MRC grade 2/5) without any sensory changes. MRI confirms adequate decompression of the C5 and C6 nerve roots with no evidence of an epidural hematoma. What is the most likely diagnosis?

. Recurrent disc herniation
. Iatrogenic spinal cord injury
. Postoperative C5 palsy
. Parsonage-Turner syndrome
. Wrong-level surgery

Correct Answer & Explanation

. Postoperative C5 palsy

Explanation

Postoperative C5 palsy is a well-recognized complication following cervical spine surgery, occurring after both anterior and posterior approaches. It typically presents as a new-onset, isolated motor deficit of the deltoid and/or biceps muscles, usually without sensory changes or long tract signs. Its exact etiology is debated but is thought to be related to nerve root tethering, shifting of the spinal cord after decompression, or local reperfusion injury. The majority of cases resolve spontaneously with conservative management and physical therapy.

Question 4954

Topic: 6. Spine



Figure 12 displays the MRI of a 50-year-old man who presents with right leg pain radiating down the anterior aspect of his thigh to the medial malleolus, along with weakness in knee extension and a diminished patellar reflex. MRI reveals a far-lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is primarily compressed by this specific herniation?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, standard paracentral disc herniations compress the traversing nerve root (e.g., an L4-L5 paracentral disc affects the L5 root). In contrast, a far-lateral (extraforaminal) disc herniation compresses the exiting nerve root at the same level in the neural foramen or further laterally. Thus, a far-lateral herniation at L4-L5 compresses the L4 nerve root. This results in L4 radiculopathy, characterized by anterior thigh pain, weakness in knee extension (quadriceps), and a diminished or absent patellar reflex.

Question 4955

Topic: 6. Spine

A 60-year-old male presents with a 6-month history of progressive clumsiness in bilateral hands and frequent tripping. Physical examination reveals a positive Hoffmann's sign and an inverted brachioradialis reflex bilaterally. MRI demonstrates severe central canal stenosis from C3 to C6. A standing lateral cervical radiograph shows a fixed cervical kyphosis of 18 degrees. Which of the following surgical approaches is most appropriate?

. C3-C6 laminectomy
. C3-C6 laminoplasty
. Anterior cervical discectomy and fusion (ACDF) C3-C6
. C1-C2 posterior instrumented fusion
. Bilateral C3-C6 posterior foraminotomies

Correct Answer & Explanation

. Anterior cervical discectomy and fusion (ACDF) C3-C6

Explanation

Cervical kyphosis greater than 13 to 15 degrees is a well-established contraindication for posterior indirect decompression techniques (such as laminectomy alone or laminoplasty). In a kyphotic spine, the spinal cord is tethered over the anterior compressive lesions and will not drift posteriorly (the 'bowstring effect') following a posterior-only decompression, leading to persistent anterior cord compression. An anterior approach (like ACDF or corpectomy) or a combined anterior-posterior approach is necessary to restore lordosis and directly decompress the cord.

Question 4956

Topic: Thoracolumbar Spine & Deformity

A 40-year-old male is brought to the trauma bay after falling from a 15-foot ladder. He is neurologically intact with full motor strength and normal sensation in the lower extremities.

CT imaging shows an L1 burst fracture with a 30% loss of anterior vertebral body height and 15% canal compromise. An MRI reveals an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his score and the recommended management?

. TLICS score 1; conservative management
. TLICS score 2; conservative management
. TLICS score 4; operative management
. TLICS score 5; operative management
. TLICS score 7; operative management

Correct Answer & Explanation

. TLICS score 2; conservative management

Explanation

The TLICS system scores based on injury morphology, neurologic status, and the integrity of the posterior ligamentous complex (PLC). Burst fracture morphology = 2 points. Neurologically intact = 0 points. Intact PLC = 0 points. The total score is 2. A TLICS score of 3 or less suggests nonoperative management (e.g., TLSO bracing). A score of 4 is considered a gray area (surgeon's choice), and a score of 5 or more indicates operative intervention.

Question 4957

Topic: Thoracolumbar Spine & Deformity

A 14-year-old competitive gymnast presents with a 9-month history of severe, unrelenting low back pain. She denies any leg pain, numbness, or weakness. Radiographs demonstrate a Grade II L5-S1 isthmic spondylolisthesis. She has failed to improve despite 6 months of rest, NSAIDs, and a targeted physical therapy program. What is the most appropriate surgical intervention?

. Direct repair of the pars interarticularis (e.g., Buck's or Scott's wiring)
. L5-S1 instrumented posterolateral fusion
. L4-S1 instrumented posterolateral fusion
. L5 laminectomy without fusion
. Anterior lumbar interbody fusion (ALIF) at L4-L5

Correct Answer & Explanation

. L5-S1 instrumented posterolateral fusion

Explanation

In an adolescent with a symptomatic Grade II isthmic spondylolisthesis who has failed exhaustive conservative management, the gold standard surgical treatment is an L5-S1 posterolateral fusion (with or without interbody fusion). Direct pars repair is generally reserved for patients with Grade I or less slips, typically at L4 or above, without significant disc degeneration. Laminectomy alone is contraindicated in this age group due to the risk of progressive instability and slip progression.

Question 4958

Topic: 6. Spine

Which of the following best summarizes the 4-year outcome data from the Spine Patient Outcomes Research Trial (SPORT) comparing surgical discectomy versus nonoperative treatment for lumbar disc herniation?

. The intention-to-treat analysis showed a statistically significant superiority of surgery over nonoperative care.
. The as-treated analysis demonstrated that patients who underwent surgery had significantly greater improvements in pain and function compared to those who did not.
. Patients treated nonoperatively had a remarkably low crossover rate (less than 10%) to the surgical group.
. Surgery resulted in a substantially higher rate of catastrophic neurological complications.
. There was no statistically significant difference between the groups in either the intention-to-treat or as-treated analyses.

Correct Answer & Explanation

. The as-treated analysis demonstrated that patients who underwent surgery had significantly greater improvements in pain and function compared to those who did not.

Explanation

The SPORT trial for lumbar disc herniation experienced high crossover rates between the operative and nonoperative cohorts (many nonoperative patients eventually chose surgery, and some surgical patients declined surgery). Due to this high crossover, the primary intention-to-treat analysis failed to show a statistically significant difference. However, the 'as-treated' analysis, which evaluated patients based on the actual treatment they received, demonstrated that surgical discectomy provided significantly greater improvements in pain, function, and satisfaction at 4 years.

Question 4959

Topic: 6. Spine

A 58-year-old male with poorly controlled type 2 diabetes presents to the emergency department with a 3-day history of worsening back pain, fevers, and new-onset inability to void. Examination reveals 3/5 strength in bilateral ankle dorsiflexion and decreased perianal sensation.

MRI of the lumbar spine reveals a substantial ventral epidural abscess spanning L2 to L4. What is the most appropriate immediate step in management?

. CT-guided aspiration and targeted intravenous antibiotics
. Emergent surgical decompression and debridement
. Broad-spectrum intravenous antibiotics and close neurologic observation
. High-dose intravenous dexamethasone followed by bracing
. Placement of a lumbar subarachnoid drain

Correct Answer & Explanation

. Emergent surgical decompression and debridement

Explanation

Spinal epidural abscesses can be managed medically (IV antibiotics) in select patients who are neurologically intact and clinically stable. However, the presence of a progressive neurologic deficit or cauda equina syndrome (indicated by bilateral weakness, perianal numbness, and urinary retention) is an absolute indication for emergent surgical decompression and debridement to prevent permanent neurologic injury.

Question 4960

Topic: Thoracolumbar Spine & Deformity
A 68-year-old female presents with progressive difficulty standing upright and severe mechanical low back pain. Full-length standing radiographs demonstrate significant adult spinal deformity. Her measured spino-pelvic parameters are: Pelvic Incidence (PI) = 58 degrees, Pelvic Tilt (PT) = 32 degrees, and Lumbar Lordosis (LL) = 20 degrees. To restore optimal sagittal alignment and minimize the risk of mechanical failure or adjacent segment disease postoperatively, what should the target Lumbar Lordosis be?
. 10 to 20 degrees
. 25 to 35 degrees
. 48 to 58 degrees
. 65 to 75 degrees
. 80 to 90 degrees

Correct Answer & Explanation

. 48 to 58 degrees

Explanation

According to the Schwab criteria for adult spinal deformity correction, optimal sagittal balance is achieved when the mismatch between Pelvic Incidence (PI) and Lumbar Lordosis (LL) is within 10 degrees (PI - LL ≤ 10°). Given a PI of 58 degrees, the ideal postoperative LL should be at least 48 degrees, making 48 to 58 degrees the correct target range.

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