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6. Spine MCQs

Practice Set 217 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 4321

Topic: 6. Spine

A 30-year-old man requires surgical stabilization of a hypermobile spondylolisthesis of L5 on S1. History reveals that he has smoked one pack of cigarettes a day for 15 years. During preoperative counseling, the patient should be advised to

. stop smoking immediately preoperatively and for at least 6 months postoperatively.
. stop smoking at least 3 months preoperatively and for 6 months postoperatively with the assistance of nicotine patches or gum.
. stop smoking postoperatively with the assistance of nicotine patches or gum.
. delay surgery to allow the patient to stop smoking for at least 6 months prior to surgery and for 6 months postoperatively.
. consider a different treatment because the rate of pseudarthrosis and clinical failure following fusion is unacceptable in smokers.

Correct Answer & Explanation

. stop smoking immediately preoperatively and for at least 6 months postoperatively.

Explanation

Many studies have shown the negative effects of cigarette smoking on the success of lumbar arthrodesis. Some have suggested preoperative cessation is a significant factor for good results. However, Deguchi and associates, in a review of spondylolisthesis fusions, and Glassman and associates, in a review of scoliosis fusions, showed no significant benefit from preoperative cessation of smoking. In every report, however, postoperative smoking correlated with a significantly increased rate of pseudarthrosis. Cessation of smoking with the use of nicotine substitutes would not be beneficial because animal studies and human clinical trials have shown that nicotine is a major factor in failure of fusion in patients who continue to smoke. Silcox DH III, Daftari T, Boden SD, Schimandle JH, Hutton WC, Whitesides TE Jr: The effect of nicotine on spinal fusion. Spine 1995;20:1549-1553. Deguchi M, Rapoff AJ, Zdeblick TA: Posterolateral fusion for isthmic spondylolisthesis in adults: Analysis of fusion rate and clinical results. J Spinal Disord 1998;11:459-464.

Question 4322

Topic: 6. Spine

A 68-year-old man presents with bilateral leg pain that worsens with walking and is relieved by leaning on a shopping cart. Examination reveals normal distal pulses and absent ankle reflexes. Which of the following findings best differentiates neurogenic claudication from vascular claudication?

. Relief of symptoms with standing still
. Proximal to distal radiation of pain
. Diminished pedal pulses
. Worsening symptoms with uphill walking
. Pallor and trophic changes in the feet

Correct Answer & Explanation

. Relief of symptoms with standing still

Explanation

Neurogenic claudication typically radiates proximal to distal and is relieved by lumbar flexion, such as sitting or leaning forward. Vascular claudication radiates distal to proximal, is relieved by standing still, and is exacerbated by uphill walking due to increased metabolic demand.

Question 4323

Topic: Thoracolumbar Spine & Deformity

A 35-year-old man falls from a roof. CT scan shows a T12 burst fracture with 40% loss of vertebral body height and splaying of the pedicles. MRI shows an intact posterior ligamentous complex (PLC). Neurological exam is completely normal. What is his Thoracolumbar Injury Classification and Severity (TLICS) score and recommended treatment?

. Score 2, Non-operative management
. Score 4, Operative management
. Score 5, Operative management
. Score 2, Operative management
. Score 4, Non-operative management

Correct Answer & Explanation

. Score 2, Non-operative management

Explanation

The TLICS score is calculated as: Burst fracture morphology (2 points), intact PLC (0 points), and intact neurologic status (0 points), totaling 2 points. A score of 3 or less is typically treated non-operatively with bracing and early mobilization.

Question 4324

Topic: 6. Spine

A 70-year-old female presents with severe neurogenic claudication and L4-L5 degenerative spondylolisthesis (Grade 1). She has failed non-operative management. According to the SPORT trial, what is the most appropriate surgical intervention?

. L4-L5 standalone anterior lumbar interbody fusion
. L4-L5 laminectomy alone
. L4-L5 laminectomy with posterolateral instrumented fusion
. L4-L5 microdiscectomy
. Interspinous process spacer placement

Correct Answer & Explanation

. L4-L5 standalone anterior lumbar interbody fusion

Explanation

The SPORT trial demonstrated that for degenerative spondylolisthesis with spinal stenosis, decompressive laminectomy with instrumented fusion provides better long-term outcomes than laminectomy alone. Laminectomy alone in the setting of instability risks further slip progression.

Question 4325

Topic: Thoracolumbar Spine & Deformity

A 22-year-old female sustains a seatbelt injury in a high-speed motor vehicle collision. Radiographs and CT show a fracture line extending horizontally through the spinous process, pedicles, and vertebral body of L2. What associated injury must be actively ruled out?

. Aortic transection
. Renal artery thrombosis
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture
. Pelvic ring disruption

Correct Answer & Explanation

. Aortic transection

Explanation

Chance fractures (flexion-distraction injuries) sustained via seatbelts are highly associated with intra-abdominal hollow viscus injuries, occurring in up to 40-50% of cases. Prompt general surgery consultation and abdominal imaging are essential.

Question 4326

Topic: 6. Spine

A patient with severe central canal stenosis at L3-L4 and L4-L5 presents with new-onset urinary incontinence and perianal numbness. Cauda equina syndrome is suspected. Which urodynamic finding is most characteristic of this condition?

. Detrusor hyperreflexia
. Decreased post-void residual
. Detrusor areflexia with overflow incontinence
. Normal cystometrogram with sphincter dyssynergia
. Increased detrusor tone

Correct Answer & Explanation

. Detrusor hyperreflexia

Explanation

Cauda equina syndrome causes lower motor neuron dysfunction, leading to a flaccid, areflexic bladder. This manifests clinically as detrusor areflexia with a large post-void residual and overflow incontinence.

Question 4327

Topic: 6. Spine

A 45-year-old male falls from a ladder, sustaining an L1 burst fracture. He has weakness in bilateral knee extension (3/5) and ankle dorsiflexion (2/5). MRI confirms severe canal compromise by a retropulsed bone fragment. What is the most appropriate surgical approach?

. Posterior short-segment pedicle screw fixation without decompression
. Anterior corpectomy and fusion with strut graft and plating
. Stand-alone kyphoplasty
. Posterior laminectomy alone
. Percutaneous pedicle screws with postural reduction

Correct Answer & Explanation

. Posterior short-segment pedicle screw fixation without decompression

Explanation

In the setting of an incomplete neurological deficit with anterior canal compromise from a burst fracture fragment, anterior decompression (corpectomy) and stabilization is highly effective. Posterior laminectomy alone is contraindicated as it destabilizes the spine without adequately addressing the anterior compressive pathology.

Question 4328

Topic: Thoracolumbar Spine & Deformity

A 40-year-old construction worker with Grade II isthmic spondylolisthesis at L5-S1 complains of severe radicular pain. If surgical decompression is planned, which nerve root is most commonly compressed in this specific pathology?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. S3 nerve root

Correct Answer & Explanation

. L4 nerve root

Explanation

In isthmic spondylolisthesis at L5-S1, the L5 nerve root is most commonly compressed as it exits the neural foramen. It is typically impinged by the hypertrophic fibrocartilaginous tissue at the pars defect.

Question 4329

Topic: 6. Spine

According to the Denis three-column theory of the spine, which of the following anatomical structures is a primary component of the middle column?

. Anterior longitudinal ligament
. Anterior half of the vertebral body
. Posterior longitudinal ligament
. Facet joint capsules
. Ligamentum flavum

Correct Answer & Explanation

. Anterior longitudinal ligament

Explanation

The Denis middle column consists of the posterior half of the vertebral body, the posterior half of the annulus fibrosus, and the posterior longitudinal ligament. Disruption of this middle column is the defining feature of a burst fracture.

Question 4330

Topic: 6. Spine

A 65-year-old female underwent an L4-S1 posterior instrumented fusion 5 years ago. She now presents with new-onset L3 radiculopathy and neurogenic claudication. Imaging confirms adjacent segment degeneration. Which intra-operative factor most significantly increases the risk of developing adjacent segment disease?

. Use of interbody cages during index surgery
. Post-operative bracing for 3 months
. Sagittal malalignment with loss of lumbar lordosis
. Using titanium rather than cobalt-chrome rods
. Age less than 50 years at index surgery

Correct Answer & Explanation

. Use of interbody cages during index surgery

Explanation

Failure to restore or maintain physiological lumbar lordosis (sagittal malalignment) significantly increases biomechanical stress on adjacent un-fused levels. This iatrogenic flatback deformity is a primary driver for adjacent segment disease.

Question 4331

Topic: 6. Spine

A patient sustains an unstable T12-L1 fracture-dislocation. He exhibits symmetric, flaccid paralysis of the lower extremities, absent bulbocavernosus reflex, and early fecal incontinence. Examination reveals a mixture of upper and lower motor neuron signs. This presentation is most consistent with:

. Spinal shock
. Cauda equina syndrome
. Conus medullaris syndrome
. Central cord syndrome
. Brown-Séquard syndrome

Correct Answer & Explanation

. Spinal shock

Explanation

Conus medullaris syndrome results from injury at the T12-L1 level and classically presents with a mix of upper and lower motor neuron signs, early sphincter dysfunction, and symmetric deficits. Cauda equina syndrome is purely lower motor neuron and usually asymmetric.

Question 4332

Topic: 6. Spine

On a T2-weighted axial MRI of the lumbar spine, a patient with severe central stenosis exhibits "redundant nerve roots." What does this finding indicate?

. Normal anatomical variant in older adults
. Acute disc herniation
. Chronic, severe mechanical compression of the cauda equina
. Congenital tethered cord syndrome
. Intradural spinal tumor

Correct Answer & Explanation

. Normal anatomical variant in older adults

Explanation

The "redundant nerve root" sign on MRI represents elongated, tortuous nerve roots proximal to a high-grade stenotic block. It is a marker of chronic, severe lumbar stenosis and correlates with poorer post-operative neurological recovery.

Question 4333

Topic: 6. Spine

A 62-year-old male with a history of long-standing ankylosing spondylitis presents with back pain after a minor ground-level fall. Initial plain radiographs of the thoracic and lumbar spine are interpreted as negative. What is the most appropriate next step in management?

. Discharge with NSAIDs and muscle relaxants
. Obtain a whole-spine CT or MRI
. Prescribe a rigid thoracolumbar orthosis (TLSO)
. Perform dynamic flexion-extension radiographs
. Schedule a dual-energy X-ray absorptiometry (DEXA) scan

Correct Answer & Explanation

. Discharge with NSAIDs and muscle relaxants

Explanation

Patients with ankylosing spondylitis have rigid, brittle spines and can sustain highly unstable transdiscal or transvertebral fractures from low-energy trauma. If radiographs are negative, advanced imaging (CT or MRI) of the entire spine is mandatory to rule out occult fractures.

Question 4334

Topic: 6. Spine

During an L3-L5 decompressive laminectomy for severe lumbar stenosis, an incidental durotomy occurs. The tear is repaired primarily with 4-0 non-absorbable suture. Which of the following is the most appropriate post-operative drain management?

. Place a subfascial drain on high wall suction
. Place an epidural drain on gravity drainage
. Avoid placing any drain to prevent a cerebrospinal fluid fistula
. Place a subfascial drain on low continuous suction
. Place a subcutaneous drain on high wall suction

Correct Answer & Explanation

. Place a subfascial drain on high wall suction

Explanation

In the setting of an incidental durotomy, drains (especially under suction) should generally be avoided to prevent pulling cerebrospinal fluid through the repair. A vacuum drain risks creating a persistent CSF fistula and hindering dural healing.

Question 4335

Topic: Thoracolumbar Spine & Deformity

A 45-year-old male treated conservatively for a T12 burst fracture one year ago presents with worsening back pain and progressive kyphosis (now 35 degrees). What is the primary biomechanical rationale for performing an anterior and posterior fusion rather than a posterior-only fusion in this setting?

. To avoid injury to the conus medullaris
. To provide a vascularized bone graft
. To address the rigid anterior column deficiency and provide load-sharing
. To allow for dynamic stabilization
. To minimize blood loss

Correct Answer & Explanation

. To avoid injury to the conus medullaris

Explanation

In delayed post-traumatic kyphosis, the anterior column is often deficient and rigidly deformed. An anterior release and strut grafting provides necessary load-sharing and addresses the anterior column defect, which a posterior-only construct would likely fail to maintain.

Question 4336

Topic: 6. Spine

A 72-year-old man with mild neurogenic claudication and L4-L5 stenosis desires minimally invasive surgery. An interspinous process spacer is being considered. Which of the following is a strict contraindication to this device?

. Age greater than 70 years
. Bilateral radicular symptoms
. Mild facet arthropathy
. Grade II or higher spondylolisthesis at the index level
. Previous microdiscectomy at a different level

Correct Answer & Explanation

. Age greater than 70 years

Explanation

Interspinous process spacers rely on an intact posterior bony arch and stable segments to maintain distraction. Gross instability, such as a Grade II or greater spondylolisthesis, is a strict contraindication as it can lead to device migration or fracture.

Question 4337

Topic: 6. Spine

A trauma patient with a known T11 burst fracture develops sudden, severe bradycardia and hypotension during transport. His extremities are warm and well-perfused. Which of the following is the most likely cause?

. Hypovolemic shock due to internal bleeding
. Neurogenic shock due to loss of sympathetic tone
. Spinal shock due to axonal transection
. Autonomic dysreflexia
. Pulmonary embolism

Correct Answer & Explanation

. Hypovolemic shock due to internal bleeding

Explanation

Sudden hypotension and bradycardia with warm, flushed extremities is the hallmark of neurogenic shock. It is caused by the loss of sympathetic tone following a spinal cord injury above T6, leading to unopposed vagal tone.

Question 4338

Topic: 6. Spine

Achondroplasia is frequently associated with early-onset symptomatic lumbar stenosis. Which anatomical feature of the lumbar spine is classically observed in these patients?

. Increased interpedicular distance from L1 to L5
. Decreased interpedicular distance from L1 to L5
. Absence of the ligamentum flavum
. Hypertrophy of the uncinate processes
. Congenital absence of the pars interarticularis

Correct Answer & Explanation

. Increased interpedicular distance from L1 to L5

Explanation

In achondroplasia, patients classically exhibit a progressive decrease in the interpedicular distance from L1 to L5, contrary to the normal spine where it widens. This leads to severe congenital central canal stenosis.

Question 4339

Topic: 6. Spine

A 68-year-old male presents with bilateral lower extremity pain and fatigue when walking. Which of the following historical findings is most specific for differentiating neurogenic claudication from vascular claudication?

. Pain relief strictly with standing still
. Diminished pedal pulses
. Pain relief when pushing a shopping cart
. Cramping in the calves that begins immediately upon walking
. Pallor of the distal extremities with elevation

Correct Answer & Explanation

. Pain relief strictly with standing still

Explanation

Neurogenic claudication is classically relieved by lumbar flexion, such as when pushing a shopping cart, because it increases the cross-sectional area of the spinal canal. Vascular claudication is typically relieved simply by resting or standing still.

Question 4340

Topic: 6. Spine

A 65-year-old female presents with severe neurogenic claudication and an L4-L5 grade I degenerative spondylolisthesis. According to the Spine Patient Outcomes Research Trial (SPORT), which of the following best describes the outcome of surgical versus nonoperative treatment at 4-year follow-up?

. Surgical treatment provides no significant difference in pain or function compared to nonoperative treatment.
. Surgical treatment shows a significant advantage over nonoperative treatment in pain and function.
. Nonoperative treatment results in higher patient satisfaction.
. Patients who crossed over to surgery had worse outcomes than those randomized to surgery.
. Decompression alone was overwhelmingly superior to decompression and fusion.

Correct Answer & Explanation

. Surgical treatment provides no significant difference in pain or function compared to nonoperative treatment.

Explanation

The SPORT trial demonstrated that patients treated surgically for degenerative spondylolisthesis maintained significantly greater improvements in pain and function at 4 years compared to those treated nonoperatively.

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