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6. Spine MCQs

Practice Set 251 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 5001

Topic: 6. Spine

A 55-year-old male with diabetes presents with a 2-week history of worsening severe midthoracic back pain, low-grade fevers, and new-onset bilateral lower extremity weakness (motor strength 3/5). MRI with gadolinium reveals a posterior epidural fluid collection with rim enhancement at T7-T9 causing severe spinal cord compression. What is the most appropriate next step in management?

. CT-guided needle aspiration and IV antibiotics
. Empirical IV antibiotics and strict bed rest
. Urgent posterior decompression and evacuation
. Urgent anterior corpectomy and strut grafting
. Radiation therapy

Correct Answer & Explanation

. Urgent posterior decompression and evacuation

Explanation

The patient presents with a thoracic spinal epidural abscess causing acute neurologic deficit (paraparesis). The presence of a progressing neurologic deficit or profound weakness is an absolute indication for urgent surgical decompression and evacuation of the abscess. Since the abscess is located posteriorly, a posterior decompression (laminectomy) is appropriate. Medical management or percutaneous aspiration alone is reserved for neurologically intact patients, those with prohibitive surgical risks, or those with prolonged (>48-72 hours) complete paralysis.

Question 5002

Topic: 6. Spine

A 62-year-old man of East Asian descent presents with progressive clumsiness in his hands and an unsteady, broad-based gait. Examination shows a positive Hoffmann's sign bilaterally. Cervical spine CT demonstrates continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6, causing severe canal stenosis. The K-line on a neutral lateral radiograph is plotted, and the OPLL mass anteriorly crosses the K-line (K-line negative). Which of the following is true regarding this finding?

. The patient will have a poor neurologic outcome following an anterior cervical corpectomy.
. The ossified mass does not cross a line connecting the midpoints of the C2 and C7 spinal canal.
. A posterior decompression alone (e.g., laminoplasty) may not provide adequate cord decompression.
. The patient has a highly flexible cervical lordosis.
. The pathology is primarily driven by ligamentum flavum hypertrophy.

Correct Answer & Explanation

. A posterior decompression alone (e.g., laminoplasty) may not provide adequate cord decompression.

Explanation

The K-line is defined as a straight line connecting the midpoints of the spinal canal at C2 and C7 on a neutral lateral radiograph. In patients with OPLL, if the ossified mass crosses this line posteriorly (K-line negative), it indicates massive OPLL or cervical kyphosis. In this scenario, posterior decompression alone (such as laminoplasty) will not allow the spinal cord to drift backward sufficiently, leading to inadequate decompression. Such patients require an anterior decompression or a posterior decompression combined with instrumented fusion to correct alignment.

Question 5003

Topic: 6. Spine

A 22-year-old restrained driver is involved in a high-speed motor vehicle collision. He complains of severe back pain. CT scans of the thoracolumbar spine show a transverse fracture through the L1 spinous process, pedicles, and posterior vertebral body, with widening of the posterior elements. There is no translation. What associated intra-abdominal injury is most likely to be present?

. Hepatic laceration
. Splenic rupture
. Hollow viscus injury
. Renal contusion
. Diaphragmatic rupture

Correct Answer & Explanation

. Hollow viscus injury

Explanation

The imaging describes a flexion-distraction injury, classically known as a Chance fracture. This type of injury is commonly sustained in high-energy deceleration accidents where a lap belt acts as a fulcrum. These fractures have a high association (up to 40-50%) with intra-abdominal injuries, most notably hollow viscus injuries (e.g., bowel perforations or mesenteric tears). Therefore, a high index of suspicion and appropriate workup (e.g., abdominal CT) are mandatory.

Question 5004

Topic: 6. Spine

A 50-year-old man with a long-standing history of ankylosing spondylitis presents to the emergency department after a low-speed rear-end motor vehicle collision. He reports new-onset neck pain but no neurologic deficits. Initial plain radiographs of the cervical spine are reported as 'normal'. What is the most appropriate next step in management?

. Discharge with NSAIDs and a soft collar
. Discharge with physical therapy
. CT scan of the entire cervical spine
. Flexion-extension radiographs of the cervical spine
. MRI of the brain

Correct Answer & Explanation

. CT scan of the entire cervical spine

Explanation

Patients with ankylosing spondylitis have highly brittle, osteopenic spines that are highly susceptible to unstable fractures even from minor trauma, most commonly extension-distraction injuries. Plain radiographs are notoriously difficult to interpret in these patients due to altered anatomy, osteopenia, and deformity, frequently missing fractures. Therefore, any patient with ankylosing spondylitis who experiences trauma and presents with new spinal pain must undergo a CT scan of the spine to rule out a fracture. Flexion-extension views are contraindicated due to the risk of displacing an occult fracture.

Question 5005

Topic: 6. Spine

A 16-year-old female gymnast presents with a 6-month history of low back pain and left leg pain that worsens with activity. Examination reveals hamstring tightness and an L5 step-off. Radiographs show a grade II L5-S1 isthmic spondylolisthesis. She is scheduled for L5-S1 decompression and instrumented fusion. During reduction of the L5 vertebra, which nerve root is at highest risk for iatrogenic injury?

. L4
. L5
. S1
. S2
. S3

Correct Answer & Explanation

. L5

Explanation

In L5-S1 isthmic spondylolisthesis, the L5 nerve root exits through the L5-S1 foramen. As the L5 vertebral body slips anteriorly, the L5 root can be stretched or compressed by the pars defect fibrocartilaginous tissue or the pedicle of L5. During surgical reduction of the slip, pulling the L5 vertebra posteriorly places significant traction on the L5 nerve root, making it the most vulnerable to iatrogenic stretch injury.

Question 5006

Topic: 6. Spine

A 45-year-old man presents with acute onset severe low back pain, bilateral lower extremity radicular pain, and numbness in his perineal region. He reports difficulty urinating for the past 12 hours. Bladder scan reveals a post-void residual (PVR) of 450 mL. An MRI of the lumbar spine shows a massive L4-L5 central disc herniation. What is the most significant prognostic factor for recovery of bladder function following surgical decompression?

. Duration of symptoms prior to decompression
. The size of the disc herniation
. The patient's age
. The presence of preoperative saddle anesthesia
. The level of the disc herniation

Correct Answer & Explanation

. Duration of symptoms prior to decompression

Explanation

The patient is presenting with acute Cauda Equina Syndrome (CES). The most significant prognostic factor for the return of normal bladder, bowel, and sexual function is the time to surgical decompression. Decompression within 24 to 48 hours of symptom onset maximizes the chances of full neurologic recovery. Delays beyond this window are associated with a significantly higher risk of permanent sphincter dysfunction.

Question 5007

Topic: 6. Spine

A 35-year-old male undergoes an anterior lumbar interbody fusion (ALIF) at L5-S1 for degenerative disc disease. Postoperatively, he notes normal erectile function but reports a lack of seminal emission during orgasm. This complication is most likely due to injury of which of the following structures?

. Superior hypogastric plexus
. Parasympathetic pelvic splanchnic nerves
. Pudendal nerve
. Genitofemoral nerve
. Lumbar sympathetic trunk at L2

Correct Answer & Explanation

. Superior hypogastric plexus

Explanation

The patient is experiencing retrograde ejaculation, a known complication of the anterior approach to the lower lumbar spine, particularly at L5-S1. This condition occurs due to injury to the superior hypogastric plexus, which lies over the bifurcation of the aorta and the anterior aspect of the L5 vertebral body. It carries sympathetic nerve fibers that control the closure of the internal urethral sphincter during ejaculation. Erectile function, mediated by parasympathetic fibers (pelvic splanchnic nerves), is typically preserved.

Question 5008

Topic: 6. Spine

A 65-year-old man presents with a 6-month history of progressive difficulty buttoning his shirts and an unsteady gait. On examination, he demonstrates bilateral positive Hoffmann signs, an inverted brachioradialis reflex, and lower extremity hyperreflexia.

The lateral cervical radiograph demonstrates a fixed 15-degree cervical kyphosis centered at C4-C6. MRI reveals severe central canal stenosis with anterior cord compression and T2 hyperintensity at C4-C5 and C5-C6. Which of the following is the most appropriate surgical intervention?

. Cervical laminectomy and posterior spinal fusion from C3-C7
. Cervical laminoplasty from C3-C7
. Anterior cervical diskectomy and fusion at C4-C5 and C5-C6
. Posterior cervical foraminotomies at C4-C5 and C5-C6
. Prolonged immobilization in a hard cervical collar

Correct Answer & Explanation

. Anterior cervical diskectomy and fusion at C4-C5 and C5-C6

Explanation

In patients with cervical spondylotic myelopathy and fixed cervical kyphosis, anterior decompression and fusion (ACDF or corpectomy) is preferred. Posterior procedures like laminectomy or laminoplasty rely on the spinal cord drifting posteriorly away from anterior compressive lesions, which does not effectively occur in rigid kyphotic deformities. Furthermore, laminectomy alone in a kyphotic spine can exacerbate the deformity.

Question 5009

Topic: 6. Spine

A 55-year-old diabetic man presents to the emergency department with severe midthoracic back pain, a fever of 39.0°C (102.2°F), and rapidly progressive paraparesis over the last 24 hours. A STAT thoracic spine MRI with contrast demonstrates a large dorsal epidural abscess spanning from T8 to T10, causing severe spinal cord compression. There is no evidence of anterior column instability, discitis, or osteomyelitis. What is the most appropriate immediate management?

. CT-guided aspiration of the epidural collection
. Administration of broad-spectrum intravenous antibiotics and close observation
. Anterior corpectomy and fusion via a thoracotomy approach
. Posterior decompressive laminectomy and abscess evacuation
. Translaminar epidural steroid injection for cord edema

Correct Answer & Explanation

. Posterior decompressive laminectomy and abscess evacuation

Explanation

This patient has a rapidly progressive neurologic deficit in the setting of a dorsal spinal epidural abscess. Emergent surgical decompression is indicated. Given the dorsal (posterior) location of the abscess without associated anterior vertebral osteomyelitis or instability, a posterior decompressive laminectomy with evacuation and irrigation of the abscess is the most direct and appropriate surgical approach.

Question 5010

Topic: Thoracolumbar Spine & Deformity

A 30-year-old man presents to the trauma bay after falling 10 feet from a ladder. He complains of moderate low back pain. He is neurologically intact with 5/5 strength in all myotomes and normal bowel/bladder function.

A CT scan shows an L2 burst fracture with 20% loss of anterior vertebral body height, 10 degrees of regional kyphosis, 30% canal compromise, and an intact posterior osseous-ligamentous complex. What is the recommended treatment?

. Posterior short-segment pedicle screw fixation one level above and below
. Anterior corpectomy, structural cage placement, and anterolateral plating
. Conservative management with a thoracolumbosacral orthosis (TLSO) and early mobilization
. Laminectomy and posterior non-instrumented fusion
. Percutaneous balloon kyphoplasty of L2

Correct Answer & Explanation

. Conservative management with a thoracolumbosacral orthosis (TLSO) and early mobilization

Explanation

Thoracolumbar burst fractures with a Thoracolumbar Injury Classification and Severity (TLICS) score of less than 4 (neurologically intact, intact posterior ligamentous complex, stable height loss/kyphosis) are generally considered stable. Multiple randomized controlled trials have demonstrated that stable thoracolumbar burst fractures in neurologically intact patients have equivalent long-term functional outcomes when treated non-operatively with bracing (TLSO) or early mobilization compared to surgical fixation.

Question 5011

Topic: Cervical Spine

An 82-year-old woman with a history of severe osteoporosis and multiple medical comorbidities presents after a low-speed motor vehicle collision. She reports severe upper neck pain. She is neurologically intact.

A cervical CT scan reveals a Type II odontoid fracture with 3 mm of posterior displacement. What is the most appropriate initial management for this patient?

. Halo vest immobilization for 12 weeks
. Rigid cervical collar immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation
. Occipitocervical fusion

Correct Answer & Explanation

. Rigid cervical collar immobilization

Explanation

In elderly patients (typically >80 years) with Type II odontoid fractures, morbidity and mortality are significantly higher than in younger cohorts. Halo vest immobilization in the elderly is poorly tolerated and associated with alarmingly high mortality and complication rates (e.g., respiratory distress, aspiration, falls). A rigid cervical collar is generally preferred as the safest initial non-operative management for symptomatic relief in elderly, infirm patients, despite accepting a higher rate of fibrous nonunion, which often proves clinically stable. Surgical stabilization (posterior C1-2 fusion) may be considered if patients fail conservative care or have progressive instability/neurologic deficits, but odontoid screws are heavily contraindicated in severe osteoporosis.

Question 5012

Topic: 6. Spine

A 45-year-old man with known ankylosing spondylitis presents to the emergency department after a seemingly minor mechanical fall from standing height. He complains of severe, localized, and new-onset mid-back pain. Anteroposterior and lateral thoracic spine radiographs demonstrate extensive syndesmophyte formation but are otherwise read as 'unremarkable' by the radiologist. His neurologic examination is perfectly normal. What is the most appropriate next step in management?

. Reassurance, NSAIDs, and physical therapy
. Advanced imaging with a CT scan or MRI of the entire spine
. Dynamic flexion-extension radiographs of the thoracic spine
. Discharge with a custom-fitted TLSO brace
. Technetium-99m bone scan

Correct Answer & Explanation

. Advanced imaging with a CT scan or MRI of the entire spine

Explanation

Patients with ankylosing spondylitis possess rigid, osteopenic spines that act as long lever arms, making them highly susceptible to unstable fractures (often transdiscal or transvertebral extension/shear injuries) even from very low-energy trauma. These fractures are notoriously difficult to visualize on plain radiographs due to the altered anatomy and extensive ossification. Any patient with ankylosing spondylitis who presents with new-onset back pain after trauma mandates advanced imaging—preferably a CT scan or MRI of the entire spine—to rule out a potentially disastrous occult fracture.

Question 5013

Topic: 6. Spine

A 60-year-old woman presents with a 4-month history of right-sided neck and arm pain radiating into her middle finger, consistent with a C7 radiculopathy. Five years ago, she underwent a C5-C6 anterior cervical diskectomy and fusion (ACDF). Radiographs show a solid fusion at C5-C6 and new, severe disc space narrowing and foraminal osteophytosis at C6-C7.

She has failed 6 months of comprehensive non-operative management. What is the most appropriate surgical option?

. C6-C7 Anterior cervical diskectomy and fusion (ACDF)
. C6-C7 Cervical disc arthroplasty (CDA)
. Posterior C5-C7 decompressive laminectomy and instrumented fusion
. C6-C7 Anterior cervical corpectomy
. Removal of anterior C5-C6 hardware and C6-C7 disc arthroplasty

Correct Answer & Explanation

. C6-C7 Anterior cervical diskectomy and fusion (ACDF)

Explanation

Symptomatic adjacent segment disease (ASD) requiring surgery after a previous ACDF is most reliably treated with an adjacent level ACDF. Cervical disc arthroplasty (CDA) is generally not indicated (and often explicitly contraindicated in FDA labeling) adjacent to a prior fusion due to altered biomechanics, although some off-label use is being studied. A corpectomy or an extensive posterior laminectomy/fusion is excessively morbid for isolated single-level adjacent segment radiculopathy.

Question 5014

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with persistent lower back pain that has prevented her from participating in sports for the past 8 months. She has undergone extensive physical therapy, bracing, and activity modification without relief. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1 with 35% translation. Her neurologic examination is intact. What is the recommended surgical procedure for this patient?

. L5 bilateral pars interarticularis defect repair
. L5-S1 posterior instrumented fusion with autogenous bone graft
. L5 laminectomy and bilateral discectomy without fusion
. L4-S1 anterior and posterior combined spinal fusion
. Sacroiliac joint fusion

Correct Answer & Explanation

. L5-S1 posterior instrumented fusion with autogenous bone graft

Explanation

In pediatric patients with a symptomatic, high-grade isthmic spondylolisthesis (or a symptomatic low-grade slip that has completely failed comprehensive non-operative management), an L5-S1 posterior instrumented fusion with bone grafting is the standard of care. Direct pars repairs are generally reserved for young patients with early-stage spondylolysis (defect only) or very minimal Grade I slips, typically at the L1-L4 levels rather than L5-S1 due to biomechanical stresses. A laminectomy alone is strictly contraindicated as it will aggressively destabilize the segment and dramatically worsen the slip.

Question 5015

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with progressively worsening lower back pain and an inability to stand completely upright. She notes that she must consciously bend her knees to maintain a forward gaze. Standing full-length scoliosis radiographs reveal a Pelvic Incidence (PI) of 60 degrees, a Lumbar Lordosis (LL) of 20 degrees, and a Sagittal Vertical Axis (SVA) of +12 cm. What is the primary radiographic goal in the surgical correction of her adult spinal deformity?

. Restore her Lumbar Lordosis to equal her Pelvic Incidence minus 40 degrees
. Achieve a postoperative Sagittal Vertical Axis of greater than 10 cm
. Restore her Lumbar Lordosis to within 10 degrees of her Pelvic Incidence
. Surgically correct her Pelvic Incidence to match her 20 degrees of Lumbar Lordosis
. Perform a single-level L5-S1 ALIF to increase anterior column height

Correct Answer & Explanation

. Restore her Lumbar Lordosis to within 10 degrees of her Pelvic Incidence

Explanation

In the surgical management of adult spinal deformity, restoring regional and global sagittal balance is paramount for favorable clinical outcomes. The widely accepted goal is to restore the patient's Lumbar Lordosis (LL) to within 10 degrees of their fixed Pelvic Incidence (PI) (i.e., PI - LL < 10 degrees). The Sagittal Vertical Axis (SVA) should ideally be corrected to less than 5 cm. Pelvic Incidence is a fixed, innate morphologic parameter of the pelvis and cannot be surgically altered or 'corrected.'

Question 5016

Topic: 6. Spine

A 72-year-old man presents with a 2-year history of worsening bilateral buttock and posterior thigh pain when walking. His symptoms are consistently relieved by sitting down or leaning forward over a shopping cart. Bilateral lower extremity pulses are palpable and bounding, and his neurologic exam is unremarkable. An MRI reveals severe central canal stenosis at L3-L4 and L4-L5 secondary to significant ligamentum flavum hypertrophy and facet arthropathy. Flexion-extension radiographs show no evidence of spondylolisthesis or dynamic instability. After failing 6 months of physical therapy and epidural steroid injections, what is the most appropriate surgical management?

. L3-L5 posterior laminectomy combined with pedicle screw fixation
. L3-L5 decompressive laminectomy alone
. L3-L5 interlaminar spinous process spacer placement
. Anterior lumbar interbody fusion (ALIF) at L3-L4 and L4-L5
. Bilateral L3-L5 microdiscectomies

Correct Answer & Explanation

. L3-L5 decompressive laminectomy alone

Explanation

In older patients with symptomatic lumbar spinal stenosis (neurogenic claudication) who have failed conservative management and have absolutely no evidence of preoperative instability (such as a degenerative spondylolisthesis) or deformity, a decompressive laminectomy alone is the gold standard surgical intervention. Major prospective trials, including the SPORT trial, have shown that adding a fusion to a decompression in patients without instability provides no additional clinical benefit but significantly increases surgical time, blood loss, complication rates, and healthcare costs.

Question 5017

Topic: 6. Spine

A 32-year-old man is evaluated in the emergency department after a shallow water diving accident. He is awake, alert, and fully cooperative. Neurologic examination demonstrates 0/5 strength in the bilateral triceps, finger flexors, and hand intrinsics, but 5/5 strength in the deltoids and biceps. Sensation is decreased in the C7, C8, and T1 dermatomes bilaterally. Lateral radiographs reveal a bilateral C6-C7 facet dislocation. Which of the following is the most appropriate initial management?

. Immediate MRI of the cervical spine
. Closed awake cranial traction reduction
. Immediate anterior cervical discectomy and fusion
. Immediate posterior cervical fusion
. Administration of high-dose methylprednisolone prior to further imaging

Correct Answer & Explanation

. Closed awake cranial traction reduction

Explanation

In an awake, alert, and cooperative patient with a cervical spine facet dislocation and a neurologic deficit, urgent closed reduction using cranial traction is indicated prior to an MRI. The awake patient can provide real-time neurologic feedback during the reduction process. If the patient were obtunded or uncooperative, an MRI would be required prior to any closed or open reduction maneuver to rule out a herniated disc that could cause secondary neurologic injury during the reduction.

Question 5018

Topic: Thoracolumbar Spine & Deformity
A 68-year-old woman with a prior L3-S1 fusion presents with severe back pain, a stooped posture, and an inability to stand up straight. Standing full-length radiographs show a pelvic incidence (PI) of 60 degrees, lumbar lordosis (LL) of 20 degrees, pelvic tilt (PT) of 35 degrees, and a sagittal vertical axis (SVA) of +12 cm. Revision corrective spinal osteotomy is planned. To optimize sagittal balance, what is the minimum lumbar lordosis (LL) that should be targeted during the reconstruction?
. 20 degrees
. 30 degrees
. 50 degrees
. 70 degrees
. 80 degrees

Correct Answer & Explanation

. 50 degrees

Explanation

For optimal sagittal alignment in adult spinal deformity, the lumbar lordosis (LL) should be matched to the patient's fixed pelvic incidence (PI). The recognized formula is PI - LL ≤ 10 degrees. With a PI of 60 degrees, the targeted LL should be at least 50 degrees (preferably closer to 60) to restore sagittal balance, reduce the compensatory high pelvic tilt, and bring the SVA under 5 cm.

Question 5019

Topic: Thoracolumbar Spine & Deformity

A 14-year-old girl presents with severe low back pain and significant hamstring tightness. She stands with a characteristic 'pelvic waddle' gait. Lateral radiographs demonstrate a Grade 4 dysplastic isthmic spondylolisthesis at L5-S1 with a high slip angle. Nonoperative management has failed. Surgical planning includes an L4-to-pelvis posterior instrumented fusion with partial reduction of the L5 vertebral body. Which nerve root is at the highest risk of injury during the reduction maneuver?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

Reduction of a high-grade dysplastic or isthmic spondylolisthesis at L5-S1 carries a well-documented risk of neurologic injury. The L5 exiting nerve root is at the highest risk. As the displaced L5 vertebral body is reduced (pulled posteriorly and translated cranially), the L5 nerve root is stretched tightly across the anterior sacral ala.

Question 5020

Topic: 6. Spine

A 55-year-old Asian man presents with an 8-month history of progressive clumsy hands, gait instability, and hyperreflexia. A positive Hoffman's sign is present bilaterally. CT of the cervical spine shows continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. The sagittal MRI shows cervical kyphosis, and the ossified mass crosses the K-line (K-line negative). Which surgical approach is most appropriate to halt the progression of his myelopathy?

. Posterior cervical laminectomy and instrumented fusion
. Posterior cervical laminoplasty
. Anterior cervical corpectomy and fusion
. Cervical disc arthroplasty
. Stand-alone anterior cervical discectomy

Correct Answer & Explanation

. Anterior cervical corpectomy and fusion

Explanation

The K-line is a line drawn from the midpoints of the spinal canal at C2 and C7 on a sagittal radiograph. When the OPLL mass crosses or exceeds the K-line (K-line negative), or in the presence of cervical kyphosis, posterior decompression alone (laminectomy or laminoplasty) will fail because the spinal cord cannot shift backward and remains tethered over the anterior compressive mass. Therefore, an anterior approach (such as corpectomy) or a combined approach is required.

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