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6. Spine MCQs

Practice Set 246 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 4901

Topic: Cervical Spine

An 85-year-old woman with severe chronic obstructive pulmonary disease, congestive heart failure, and osteoporosis sustains a Type II odontoid fracture with 3 mm of posterior displacement after a mechanical fall. She complains of neck pain but has no neurological deficits. What is the most appropriate initial management for this patient?

. Halo vest immobilization
. Rigid cervical orthosis
. Anterior odontoid screw fixation
. C1-C2 posterior instrumented fusion
. Occipitocervical fusion

Correct Answer & Explanation

. Rigid cervical orthosis

Explanation

In octogenarians with multiple medical comorbidities, the treatment of Type II odontoid fractures often favors conservative management with a rigid cervical orthosis (collar). Halo vest immobilization is generally contraindicated in the elderly due to a high risk of respiratory complications, pin tract infections, dysphagia, and mortality. While surgical stabilization (C1-C2 posterior fusion) offers the highest union rate, the perioperative morbidity and mortality in frail, elderly patients with significant medical conditions (COPD, CHF) are very high. Although a collar may lead to a fibrous nonunion, this nonunion is typically stable and clinically well-tolerated.

Question 4902

Topic: 6. Spine

A 30-year-old man sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following a high-speed motor vehicle collision. Lateral radiographs demonstrate significant angulation at the C2-C3 interspace with minimal translation. When longitudinal cervical traction is applied in the emergency department, the C2-C3 angulation paradoxically increases. Based on the Levine and Edwards classification, what is the most appropriate definitive management for this specific injury pattern?

. Continued longitudinal skeletal traction for 6 weeks followed by a rigid collar
. Application of a halo vest with slight compression and extension
. Immediate anterior C2-C3 discectomy and fusion
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation

Correct Answer & Explanation

. Application of a halo vest with slight compression and extension

Explanation

This patient has a Type IIA Hangman's fracture, characterized by severe angulation and minimal translation, typically resulting from a flexion-distraction injury. The posterior longitudinal ligament and C2-C3 disc are disrupted. A defining feature of a Type IIA fracture is that longitudinal traction exacerbates the deformity (increases angulation) because the injury is already distracted. The correct management is closed reduction under fluoroscopy with slight compression and extension, followed by application of a halo vest.

Question 4903

Topic: 6. Spine

A 52-year-old man with a history of intravenous drug use presents with 2 weeks of worsening lower back pain and low-grade fever. Neurological examination reveals full 5/5 strength in all lower extremity muscle groups, normal reflexes, intact sensation, and normal rectal tone. Laboratory studies show a WBC of 14,000/ยตL, ESR of 85 mm/hr, and CRP of 120 mg/L. MRI with contrast reveals an epidural abscess from L3 to L5 causing moderate thecal sac compression. Blood cultures return positive for methicillin-sensitive Staphylococcus aureus (MSSA). What is the most appropriate initial management?

. Immediate surgical decompression via laminectomy and debridement
. Intravenous cefazolin and close neurological observation
. CT-guided needle aspiration of the epidural abscess
. Lumbar puncture to obtain CSF for comprehensive culture
. Placement of an intrathecal antibiotic pump

Correct Answer & Explanation

. Intravenous cefazolin and close neurological observation

Explanation

The patient has a spontaneous spinal epidural abscess (SEA). Although SEA is often a surgical emergency, non-operative management with targeted intravenous antibiotics and extremely close neurological monitoring is indicated if the patient is entirely neurologically intact, the causative organism is known (positive blood cultures for MSSA), and there is no significant spinal instability or deformity. Surgery is indicated if there is neurological deficit, failure of medical therapy, spinal instability, or if the organism is unknown and a tissue diagnosis is required.

Question 4904

Topic: 6. Spine

A 68-year-old man underwent an L3-L5 posterior spinal decompression and instrumented fusion 3 years ago. He now presents with severe low back pain and radiculopathy corresponding to the L2-L3 level. Radiographs reveal progressive stenosis and listhesis at L2-L3. Which of the following factors has been most significantly correlated with an increased risk of developing adjacent segment disease (ASD) following a lumbar fusion?

. The use of titanium instead of cobalt-chrome alloy rods
. Postoperative sagittal imbalance with a substantial pelvic incidence to lumbar lordosis (PI-LL) mismatch
. Performing an interbody fusion compared to a posterolateral fusion alone
. The utilization of recombinant human bone morphogenetic protein-2 (rhBMP-2)
. Patient age younger than 50 years at the time of the index surgery

Correct Answer & Explanation

. Postoperative sagittal imbalance with a substantial pelvic incidence to lumbar lordosis (PI-LL) mismatch

Explanation

Adjacent segment disease (ASD) is a well-recognized complication after lumbar fusion. Postoperative sagittal imbalance, specifically a mismatch between pelvic incidence and lumbar lordosis (PI-LL mismatch typically > 10 degrees), is one of the most critical biomechanical risk factors for developing ASD. Loss of lumbar lordosis shifts the weight-bearing axis anteriorly, increasing mechanical stress on the adjacent unfused segments. Other risk factors include advanced age, damage to the adjacent facet capsule during the index surgery, and fusion length.

Question 4905

Topic: 6. Spine

A 45-year-old woman is evaluated in the emergency department for severe low back pain, bilateral lower extremity radicular pain, saddle anesthesia, and new-onset acute urinary retention. She notes the urinary retention began approximately 12 hours ago. MRI reveals a massive extruded disc herniation at L4-L5 severely compressing the cauda equina. Regarding surgical intervention for Cauda Equina Syndrome with urinary retention (CES-R), which of the following statements most accurately reflects current evidence on timing and outcomes?

. Decompression within 24 to 48 hours of symptom onset provides the highest likelihood of significant bladder and motor function recovery
. Decompression must be performed within 4 hours of onset; after 4 hours, surgical outcomes are uniformly poor
. Surgical decompression should be delayed until a 48-hour trial of high-dose intravenous dexamethasone is completed
. Because the patient has established urinary retention (CES-R), bladder recovery is impossible regardless of surgical timing
. Delaying surgery for 72 hours to allow local perineural edema to subside yields better long-term functional outcomes

Correct Answer & Explanation

. Decompression within 24 to 48 hours of symptom onset provides the highest likelihood of significant bladder and motor function recovery

Explanation

Cauda Equina Syndrome (CES) is a surgical emergency. The literature, including landmark meta-analyses by Ahn et al. and Todd, demonstrates that decompression performed within 24 to 48 hours of symptom onset is associated with a significantly better chance of neurological and functional recovery, including bladder, bowel, and motor function. While outcomes are generally poorer for patients presenting with established urinary retention (CES-R) compared to incomplete CES (CES-I), prompt surgical decompression within the 24-48 hour window is still strictly indicated to maximize the chance of functional return.

Question 4906

Topic: 6. Spine

A 60-year-old male with a history of intravenous drug use presents with 48 hours of progressive bilateral lower extremity weakness, sensory loss below the umbilicus, and severe midthoracic back pain. His temperature is 38.8ยฐC (101.8ยฐF). MRI with contrast reveals a large, peripherally enhancing posterior epidural collection extending from T4 to T8 with severe spinal cord compression. Which of the following is the most appropriate management?

. Intravenous antibiotics alone and close neurologic monitoring
. Multi-level thoracic laminectomy, evacuation of the abscess, and targeted intravenous antibiotics
. Anterior thoracic corpectomy with strut grafting and plating
. CT-guided percutaneous needle aspiration
. Posterior spinal fusion from T2 to T10 without decompression

Correct Answer & Explanation

. Multi-level thoracic laminectomy, evacuation of the abscess, and targeted intravenous antibiotics

Explanation

This patient presents with a spinal epidural abscess causing an acute neurologic deficit (myelopathy/paraparesis). The presence of a neurologic deficit is an absolute indication for emergent surgical decompression. Because the abscess is located posteriorly, a multi-level laminectomy and evacuation is the most appropriate surgical approach, followed by prolonged culture-specific intravenous antibiotics.

Question 4907

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male falls 10 feet from a ladder and sustains an L1 burst fracture. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). Based on the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the generally recommended treatment?

. Score 2; nonoperative management
. Score 4; nonoperative management
. Score 4; operative management
. Score 5; operative management
. Score 7; operative management

Correct Answer & Explanation

. Score 2; nonoperative management

Explanation

The TLICS system scores injuries based on morphology, neurologic status, and the integrity of the posterior ligamentous complex (PLC). A burst fracture morphology scores 2 points. Intact neurologic status scores 0 points. An intact PLC scores 0 points. The total score is 2. A TLICS score < 4 is an indication for nonoperative management (e.g., bracing or early mobilization depending on pain and stability).

Question 4908

Topic: 6. Spine

A 58-year-old male presents with progressively worsening manual dexterity, broad-based gait, and hyperreflexia in the lower extremities. MRI of the cervical spine demonstrates severe central canal stenosis at C4-C5 and C5-C6 with spinal cord signal changes. Which of the following MRI signal characteristics is associated with the poorest prognosis for neurologic recovery following surgical decompression?

. T1-weighted hypointensity within the spinal cord
. Focal T2-weighted hyperintensity within the spinal cord
. Multilevel T2-weighted hyperintensity confined to the grey matter
. T1-weighted hyperintensity in the adjacent vertebral bodies
. T2-weighted hypointensity of the intervertebral discs

Correct Answer & Explanation

. T1-weighted hypointensity within the spinal cord

Explanation

In patients with cervical spondylotic myelopathy (CSM), intrinsic spinal cord signal changes on MRI are prognostic. T2-weighted hyperintensity is common and represents edema, inflammation, or gliosis, and is associated with a variable prognosis. However, T1-weighted hypointensity indicates irreversible cystic necrosis and myelomalacia, which is strongly associated with a poor prognosis for neurologic recovery after decompressive surgery.

Question 4909

Topic: Thoracolumbar Spine & Deformity

A 16-year-old female gymnast complains of 6 months of persistent lower back pain that is worsened with spinal extension. She has failed physical therapy and bracing. Upright lateral radiographs demonstrate a Grade I isthmic spondylolisthesis at L5-S1. What is the most appropriate surgical intervention?

. Direct repair of the pars interarticularis defects (e.g., Buck's technique)
. In situ posterolateral fusion of L5-S1 with instrumentation
. Anterior lumbar interbody fusion (ALIF) of L4-L5
. L5 laminectomy without fusion
. L4-L5-S1 posterior spinal fusion

Correct Answer & Explanation

. In situ posterolateral fusion of L5-S1 with instrumentation

Explanation

In symptomatic pediatric or adolescent patients with a Grade I isthmic spondylolisthesis at L5-S1 that has failed extensive nonoperative treatment, in situ instrumented posterolateral fusion of L5-S1 is the standard surgical treatment. Direct pars repair (e.g., Buck, Scott, or Morscher techniques) is reserved for patients with symptomatic spondylolysis (pars defect) without significant slippage (spondylolisthesis), and is most commonly performed at L4 or above. Direct repair at L5-S1 in the presence of a slip has a high failure rate.

Question 4910

Topic: 6. Spine

A 68-year-old male with a 30-year history of ankylosing spondylitis sustains a low-energy fall and presents with severe lower cervical pain. He is initially neurologically intact. CT imaging confirms a displaced, transdiscal extension-type fracture at C6-C7. Within hours of admission, he develops progressive quadriplegia. What is the most likely cause of his delayed neurologic deterioration?

. Epidural hematoma
. Vertebral artery dissection
. Syringomyelia
. Acute post-traumatic meningomyelocele
. Autonomic dysreflexia

Correct Answer & Explanation

. Epidural hematoma

Explanation

Patients with ankylosing spondylitis have rigidly fused, brittle spines that are highly susceptible to fracture even from minor trauma. These fractures are notoriously unstable and shear forces can tear the epidural venous plexus. An acute spinal epidural hematoma is a well-documented and devastating complication in this population, which can rapidly lead to delayed, progressive neurologic deficits (quadriplegia or paraplegia) requiring emergent decompression.

Question 4911

Topic: Thoracolumbar Spine & Deformity

A 65-year-old female presents with severe mechanical lower back pain, early satiety, and a flexed posture. Radiographs reveal a severe degenerative flatback deformity. Her measured pelvic incidence (PI) is 58 degrees. To achieve optimal spinopelvic alignment and clinical outcomes postoperatively, what should her target lumbar lordosis (LL) ideally be?

. 20 degrees
. 38 degrees
. 58 degrees
. 78 degrees
. 90 degrees

Correct Answer & Explanation

. 58 degrees

Explanation

In the surgical correction of adult spinal deformity, achieving appropriate spinopelvic alignment is critical for good functional outcomes. A key principle (Schwab criteria) is that the postoperative lumbar lordosis (LL) should match the patient's fixed pelvic incidence (PI) within 9 degrees (LL = PI ยฑ 9ยฐ). Therefore, for a PI of 58 degrees, a target LL of approximately 58 degrees is ideal to minimize the pelvic tilt and restore upright sagittal balance.

Question 4912

Topic: 6. Spine

A 45-year-old male presents with acute onset of severe right anterior thigh pain and weakness in knee extension. Examination reveals an absent right patellar reflex and sensory diminished over the medial aspect of the right lower leg. MRI of the lumbar spine reveals a far lateral (extraforaminal) disc herniation at the L4-L5 level on the right. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

In the lumbar spine, a paracentral disc herniation typically compresses the traversing nerve root (e.g., L5 at the L4-L5 level). However, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at that level. Therefore, a far lateral herniation at L4-L5 compresses the L4 nerve root, which manifests as weakness in knee extension (quadriceps), an absent patellar reflex, and sensory loss over the medial aspect of the lower leg.

Question 4913

Topic: Cervical Spine

A 55-year-old female with long-standing, poorly controlled rheumatoid arthritis complains of occipital headache and "electric shock" sensations radiating down her arms when she flexes her neck. Flexion-extension radiographs demonstrate atlantoaxial subluxation. Which of the following radiographic measurements indicates the highest risk for impending neurologic deficit and serves as a strong indication for surgical stabilization?

. Anterior atlantodental interval (ADI) > 3 mm
. Posterior atlantodental interval (PADI) < 14 mm
. Basilar invagination > 2 mm above Chamberlain's line
. C2-C7 sagittal vertical axis > 4 cm
. T1 slope > 20 degrees

Correct Answer & Explanation

. Posterior atlantodental interval (PADI) < 14 mm

Explanation

In rheumatoid arthritis, atlantoaxial subluxation is common. While the anterior atlantodental interval (ADI) measures the amount of subluxation, the posterior atlantodental interval (PADI), also known as the space available for the cord (SAC), is the most reliable predictor of neurologic deficit. A PADI of less than 14 mm indicates critical stenosis and a high risk of permanent neurologic injury, warranting surgical intervention (typically C1-C2 fusion).

Question 4914

Topic: 6. Spine

A 42-year-old male presents to the emergency department with severe lower back pain and bilateral radicular leg pain. He reports the onset of urinary incontinence starting 8 hours ago. Examination reveals complete perineal anesthesia (saddle anesthesia) and absent anal sphincter tone. MRI confirms a massive L4-L5 central disc extrusion. Following emergent decompression, which of the following is the most reliable predictor of poor postoperative bladder function recovery?

. The degree of thecal sac compression seen on MRI
. Complete perineal anesthesia at the time of presentation
. The duration of isolated back pain prior to the onset of sciatica
. The specific lumbar level of the herniation
. The presence of diminished Achilles reflexes

Correct Answer & Explanation

. Complete perineal anesthesia at the time of presentation

Explanation

The most significant prognostic factor for functional recovery in Cauda Equina Syndrome (CES) is the severity of neurologic impairment at presentation. Patients with incomplete CES (retention with intact or partial perineal sensation) have a significantly better prognosis for bladder recovery postoperatively. Patients presenting with complete CES, characterized by painless urinary retention/overflow incontinence and complete perineal anesthesia, have a much poorer prognosis for full recovery of urologic and sexual function.

Question 4915

Topic: Cervical Spine

Figure 24 shows the lateral radiograph of an 84-year-old man who sustained a ground-level fall. He complains of high neck pain but is neurologically intact. CT scan confirms a Type II odontoid fracture with 1 mm of posterior displacement. If non-operative management is selected for this patient, which of the following orthoses is associated with the highest mortality rate in this specific demographic?

. Rigid cervical collar
. Soft cervical collar
. Halo vest immobilization
. Sterno-occipital mandibular immobilizer (SOMI)
. Minerva cast

Correct Answer & Explanation

. Rigid cervical collar

Explanation

Halo vest immobilization in the elderly (especially >80 years of age) is associated with significant morbidity and a high mortality rate (reported up to 40% in some studies). Complications include respiratory compromise, pneumonia, pin tract infections, and falls due to altered center of gravity. For elderly patients with Type II odontoid fractures where surgery is contraindicated or not preferred, current guidelines heavily favor the use of a rigid cervical collar, accepting a higher rate of fibrous nonunion, as it provides adequate pain control with significantly lower mortality.

Question 4916

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman presents with progressive low back pain and difficulty standing upright. Standing full-length lateral spine radiographs reveal a Pelvic Incidence (PI) of 60 degrees and a Pelvic Tilt (PT) of 35 degrees. What is her Sacral Slope (SS), and what does this PT value indicate about her compensatory mechanism?

. SS is 25 degrees; indicates pelvic retroversion to compensate for sagittal malalignment.
. SS is 95 degrees; indicates pelvic anteversion to compensate for sagittal malalignment.
. SS is 25 degrees; indicates pelvic anteversion to compensate for coronal malalignment.
. SS is 95 degrees; indicates pelvic retroversion to compensate for coronal malalignment.
. SS is 35 degrees; indicates normal sagittal alignment.

Correct Answer & Explanation

. SS is 25 degrees; indicates pelvic retroversion to compensate for sagittal malalignment.

Explanation

The morphological parameter Pelvic Incidence (PI) is a fixed anatomical parameter and is the sum of Pelvic Tilt (PT) and Sacral Slope (SS) (PI = PT + SS). Therefore, SS = PI - PT = 60 - 35 = 25 degrees. A high Pelvic Tilt (normal is usually < 20 degrees) indicates pelvic retroversion. Pelvic retroversion is a primary compensatory mechanism for positive sagittal imbalance (often due to loss of lumbar lordosis) in an attempt to keep the center of gravity over the feet and maintain an upright posture.

Question 4917

Topic: 6. Spine

Figure 17 shows imaging of a 55-year-old man of East Asian descent presenting with progressive clumsiness in his hands and a wide-based gait. Imaging demonstrates Ossification of the Posterior Longitudinal Ligament (OPLL) from C3 to C6 with a K-line that is negative. Which of the following is the most appropriate surgical strategy?

. Anterior cervical discectomy and fusion (ACDF)
. Cervical laminoplasty alone
. Cervical laminectomy alone
. Anterior cervical corpectomy and fusion (ACCF) or posterior decompression with instrumentation
. Posterior cervical foraminotomy

Correct Answer & Explanation

. Anterior cervical corpectomy and fusion (ACCF) or posterior decompression with instrumentation

Explanation

A "K-line negative" cervical spine indicates that the OPLL mass crosses the K-line (a line connecting the midpoints of the spinal canal at C2 and C7 on a neutral lateral radiograph or mid-sagittal MRI). In K-line negative patients, posterior decompression alone (such as laminoplasty or laminectomy) is contraindicated because the spinal cord will not adequately drift posteriorly away from the anterior compressive mass, leading to poor neurologic recovery or deterioration. These patients require either an anterior approach (e.g., ACCF) to directly remove the mass or a posterior decompression coupled with instrumented fusion to correct the kyphosis.

Question 4918

Topic: 6. Spine

A 35-year-old construction worker falls from a height of 15 feet. Neurological examination reveals 3/5 strength in ankle dorsiflexion and EHL bilaterally, with intact bowel and bladder function. CT scan of the thoracolumbar spine demonstrates an L1 burst fracture. MRI reveals complete disruption of the posterior interspinous ligaments and ligamentum flavum. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the recommended treatment?

. Score 4; conservative management with a TLSO brace
. Score 5; surgical stabilization
. Score 7; surgical stabilization
. Score 8; surgical stabilization
. Score 9; conservative management

Correct Answer & Explanation

. Score 8; surgical stabilization

Explanation

The TLICS score is based on three categories: injury morphology, neurological status, and posterior ligamentous complex (PLC) integrity. In this scenario: Morphology is a Burst fracture = 2 points. Neurological status is incomplete (cauda equina or incomplete cord) = 3 points. PLC integrity shows complete disruption = 3 points. Total score = 2 + 3 + 3 = 8 points. A TLICS score of 4 can be treated non-operatively or operatively, while a score of 5 or greater is an absolute indication for surgical stabilization.

Question 4919

Topic: 6. Spine

Figure 6 shows the sagittal T2-weighted MRI of a 60-year-old diabetic patient presenting with severe back pain, fever, and progressive bilateral leg weakness over the past 24 hours. Laboratory studies show an ESR of 85 mm/hr and CRP of 120 mg/L. MRI confirms a ventral epidural abscess at L2-L4. Blood cultures are drawn in the emergency department. What is the most appropriate next step in management?

. Start broad-spectrum intravenous antibiotics and observe
. CT-guided aspiration of the epidural space
. Urgent surgical decompression and debridement
. Lumbar puncture for cerebrospinal fluid analysis
. High-dose intravenous corticosteroids

Correct Answer & Explanation

. Urgent surgical decompression and debridement

Explanation

A spinal epidural abscess presenting with progressive or profound neurological deficits is a surgical emergency. While medical management alone (intravenous antibiotics after cultures) may be appropriate for selected patients who are neurologically intact, poor surgical candidates, or have extensive pan-spinal abscesses without focal cord/cauda equina compression, the presence of progressive neurological deficits (bilateral leg weakness) dictates the need for urgent surgical decompression (e.g., laminectomy) and debridement to prevent irreversible paralysis.

Question 4920

Topic: 6. Spine

A 65-year-old female presents with severe neurogenic claudication and L4-L5 Grade 1 degenerative spondylolisthesis. After failing 6 months of conservative management, she is considering surgery. Based on long-term data from the Spine Patient Outcomes Research Trial (SPORT), what is the expected outcome of surgical decompression and fusion compared to non-operative treatment for this condition?

. Surgery provides a significant advantage in pain and function at 4 years, but outcomes equalize between groups at 8 years.
. Surgery is significantly superior to non-operative treatment at both 4 and 8 years for pain and function.
. Non-operative treatment shows equivalent results to surgery at 2 years.
. Decompression alone has lower reoperation rates compared to decompression with instrumented fusion.
. There is no difference in the rate of adjacent segment disease between operative and non-operative groups.

Correct Answer & Explanation

. Surgery is significantly superior to non-operative treatment at both 4 and 8 years for pain and function.

Explanation

The SPORT trial for degenerative spondylolisthesis demonstrated that surgically treated patients maintained significantly greater improvements in pain and function at 4 and 8 years compared to those treated non-operatively. The operative cohort showed durable advantages in patient-reported outcome measures (SF-36 and ODI) despite some crossover between the groups.

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