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6. Spine MCQs

Practice Set 130 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 2581

Topic: 6. Spine
Figures 28a and 28b show the sagittal and axial lumbar MRI scans of a 72-year-old man who reports dull aching back pain that spreads to his legs, calves, and buttocks. He has had the pain for several years and it is precipitated by standing and walking and relieved by sitting. His symptoms have been worsening over the past year and he notes that he is leaning forward while walking to help relieve his symptoms. He has had no treatment to date. What is his prognosis if he chooses to pursue nonsurgical management for this condition?
. He can expect complete resolution of his symptoms during the first month.
. All patients experience relief within 3 months and continue to improve over the next 4 years.
. Most patients experience some pain relief within the first 3 months.
. He may experience some improvement but if he requires surgery at a later date he will have a poorer result because of the delay.
. The patient requires immediate surgery to avoid permanent nerve damage.

Correct Answer & Explanation

. Most patients experience some pain relief within the first 3 months.

Explanation

DISCUSSION: The patient has lumbar spinal stenosis and the MRI scans reveal the pathology at L4-5, which is secondary to posterior disk bulging and hypertrophy and infolding of the ligamentum flavum, as well as degenerative facet arthrosis. The degree of spinal stenosis is moderate and his symptoms are positional in nature. Tadokoro and associates reported on a prospective study of 89 patients older than 70 years of age who underwent nonsurgical management for lumbar spinal stenosis. They found the prognosis to be relatively good with patients scoring at “excellent” or “good” for activities of daily living at final follow-up. However, they did note that patients with a complete block on myelography did not respond favorably to nonsurgical management. Amundsen and associates reported on a 10-year prospective study comparing surgical care to nonsurgical management. They concluded that, while the long-term results largely favored surgical treatment, more than half of the nonsurgically managed patients had a satisfactory outcome. They also concluded that a delay of surgery for some months did not worsen the prognosis. Therefore, their recommendation was for an initial primarily nonsurgical approach. REFERENCES: Amundsen T, Weber H, Nordal HJ, et al: Lumbar spinal stenosis: Conservative or surgical management? A prospective 10-year study. Spine 2000;25:1424-1435. Hilibrand AS, Rand N: Degenerative lumbar stenosis: Diagnosis and management. J Am Acad Orthop Surg 1999;7:239-249. Tadokoro K, Miyamoto H, Sumi M, et al: The prognosis of conservative treatments for lumbar spinal stenosis: Analysis of patients over 70 years of age. Spine 2005;30:2458-2463.

Question 2582

Topic: 6. Spine

A 22-year-old man has an acute spinal cord injury after a diving accident. Preliminary radiographs reveal bilateral jumped facets at C6-7. Neurologic examination shows an incomplete spinal cord injury consistent with an ASIA B impairment grade. The patient is otherwise hemodynamically stable with no other injuries. Attempts at closed high weight reduction with tong traction have so far been unsuccessful. What is the most appropriate management at this time? Review Topic

. Continue a high weight closed reduction of the fracture-dislocation
. Urgent surgical intervention for reduction and decompression
. High-dose steroids for 48 hours before surgical stabilization
. Halo fixation
. Closed reduction under general anesthesia

Correct Answer & Explanation

. Continue a high weight closed reduction of the fracture-dislocation

Explanation

Although there are no current standards for the timing of surgical intervention for acute spinal cord injuries there is increasing data, including animal studies, suggesting that early decompression and stabilization of an acute spinal cord injury can be beneficial. Continuing attempts at closed reduction is not advised given the failure of attempted high weight reduction. In light of the neurologic deficit, waiting 48 hours with or without steroid treatment is not recommended. Likewise, halo fixation without reduction of the dislocation should not be considered for definitive treatment. Closed reductions should not be performed under general anesthesia.

Question 2583

Topic: 6. Spine

A 65-year-old man presents with progressive gait unsteadiness and loss of fine motor skills in his hands over the past 8 months. Examination reveals a positive Hoffmann's sign and hyperreflexia in the lower extremities. MRI of the cervical spine demonstrates severe multi-level spondylotic myelopathy. Which of the following MRI findings is the most reliable predictor of poor neurologic recovery following surgical decompression?

. T2 hyperintensity without T1 changes
. Combined T1 hypointensity and T2 hyperintensity in the spinal cord
. Modic Type 1 changes in the adjacent endplates
. Severe ligamentum flavum hypertrophy
. T1 hyperintensity in the spinal cord

Correct Answer & Explanation

. T2 hyperintensity without T1 changes

Explanation

In cervical spondylotic myelopathy, signal changes in the spinal cord can predict postoperative outcomes. T2 hyperintensity alone indicates cord edema, gliosis, or early myelomalacia, and its prognostic value is debated. However, the combination of T1 hypointensity (indicating cystic necrosis/myelomalacia) and T2 hyperintensity is a strong predictor of a poor prognosis for neurologic recovery after decompression.

Question 2584

Topic: 6. Spine

A 52-year-old man with a history of intravenous drug use presents with severe back pain, fevers, and new-onset profound right foot drop. His ESR is 95 mm/hr and CRP is 120 mg/L. MRI confirms a large dorsal epidural abscess at L4-L5 with severe thecal sac compression. What is the most appropriate next step in management?

. Intravenous vancomycin and ceftriaxone with close observation
. CT-guided aspiration of the epidural space
. Emergent posterior decompressive laminectomy and debridement
. Posterior spinal fusion with instrumentation
. Intravenous steroids followed by directed antibiotic therapy

Correct Answer & Explanation

. Intravenous vancomycin and ceftriaxone with close observation

Explanation

Spinal epidural abscesses presenting with acute, profound neurologic deficits (such as a foot drop) mandate emergent surgical decompression and debridement. Medical management (antibiotics alone) is reserved for patients who are neurologically intact with high surgical risk, or those with complete paralysis for >48 hours where recovery is highly unlikely. Early decompression (<24-36 hours of deficit onset) yields the best neurologic outcomes.

Question 2585

Topic: 6. Spine

A newborn is evaluated for a spinal deformity noted at birth. Radiographs reveal a congenital spinal anomaly. Which of the following specific congenital vertebral anomalies carries the highest risk of rapid curve progression and often requires early in situ fusion?

. Single fully segmented hemivertebra
. Block vertebra
. Unilateral unsegmented bar with contralateral hemivertebra
. Incarcerated hemivertebra
. Wedge vertebra

Correct Answer & Explanation

. Single fully segmented hemivertebra

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra represents a combined defect of both formation and segmentation. This creates a severe tether on one side with active growth on the contralateral side, resulting in the highest risk of rapid curve progression among congenital anomalies. Early in situ fusion is highly recommended to prevent severe deformity.

Question 2586

Topic: 6. Spine

A 68-year-old woman presents with severe mechanical low back pain, forward stooping posture, and early satiety. Radiographs demonstrate degenerative adult spinal deformity. Her measured pelvic incidence (PI) is 60°. To restore optimal spinopelvic sagittal balance postoperatively, what is the surgical target for her lumbar lordosis (LL)?

. 30°
. 40°
. 50°
. 60°
. 80°

Correct Answer & Explanation

. 30°

Explanation

According to the Schwab criteria for adult spinal deformity, optimal sagittal balance is achieved when the lumbar lordosis (LL) matches the pelvic incidence (PI) within 9 degrees (PI - LL < 10°). Since her PI is 60°, the target LL should be approximately 60°.

Question 2587

Topic: Thoracolumbar Spine & Deformity
A 16-year-old male gymnast presents with chronic low back pain and radicular symptoms radiating down his left leg. Lateral radiographs demonstrate a L5-S1 isthmic spondylolisthesis with a 65% slip (Meyerding Grade III). Which nerve root is most commonly compressed in this specific condition?
. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

In L5-S1 isthmic spondylolisthesis, the pars interarticularis defect leads to anterior translation of L5 on S1. The fibrocartilaginous tissue at the pars defect (Gill nodule) and the slipping of the L5 vertebra cause compression of the exiting L5 nerve root within the neural foramen. This is in contrast to degenerative spondylolisthesis, where the traversing root is typically compressed in the lateral recess.

Question 2588

Topic: Thoracolumbar Spine & Deformity

A 35-year-old man falls from a 10-foot ladder and sustains a thoracolumbar injury. He is neurologically intact. CT demonstrates an L1 burst fracture with 40% loss of anterior body height and 20% canal compromise. MRI confirms that the posterior ligamentous complex (PLC) is fully intact. Based on the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score and the recommended management?

. TLICS 2, non-operative management
. TLICS 4, operative management
. TLICS 5, operative management
. TLICS 2, operative management
. TLICS 4, non-operative management

Correct Answer & Explanation

. TLICS 2, non-operative management

Explanation

The TLICS scoring system dictates treatment based on morphology, neurologic status, and PLC integrity. Morphology: Burst fracture = 2 points. Neurologic status: Intact = 0 points. PLC: Intact = 0 points. Total score = 2. A score of 3 or less indicates non-operative management. A score of 4 is the watershed (operative vs. non-operative), and 5 or more indicates operative intervention.

Question 2589

Topic: 6. Spine

A 55-year-old woman with a 20-year history of rheumatoid arthritis complains of severe occipital headaches and upper extremity paresthesias. Lateral cervical spine radiographs show anterior atlantoaxial subluxation. Which of the following measurements is the most critical and direct predictor of impending neurologic deficit, indicating the need for surgical stabilization?

. Anterior atlanto-dens interval (AADI) > 3 mm
. Anterior atlanto-dens interval (AADI) > 6 mm
. Posterior atlanto-dens interval (PADI) < 14 mm
. Basion-dental interval > 12 mm
. Ranawat value < 13 mm

Correct Answer & Explanation

. Anterior atlanto-dens interval (AADI) > 3 mm

Explanation

In rheumatoid arthritis of the cervical spine, the Posterior Atlanto-Dens Interval (PADI) directly measures the space available for the spinal cord (SAC). A PADI of < 14 mm is highly correlated with the development of myelopathy and is a strict indication for surgical stabilization, whereas AADI is less reliable due to potential concurrent dens erosion.

Question 2590

Topic: 6. Spine
A 15-year-old boy presents with progressive mid-back pain and a rounded posture. Standing lateral radiographs reveal a thoracic kyphosis of 65°. Which of the following defines the strict Sorensen radiographic criteria for the diagnosis of Scheuermann's kyphosis?
. Anterior wedging of ≥ 5° in three consecutive vertebrae
. Anterior wedging of ≥ 10° in two consecutive vertebrae
. Schmorl's nodes in at least two adjacent vertebrae with normal endplates
. Thoracic kyphosis > 45° with isolated endplate irregularities
. Vertebral body collapse of > 50% in a single vertebra

Correct Answer & Explanation

. Anterior wedging of ≥ 5° in three consecutive vertebrae

Explanation

The classic Sorensen criteria for diagnosing Scheuermann's disease include anterior wedging of at least 5 degrees in three or more consecutive vertebrae. Associated findings often include Schmorl's nodes, endplate irregularities, and narrowed disc spaces, but the consecutive wedging is the defining criteria.

Question 2591

Topic: 6. Spine

A 14-year-old female soccer player presents with acute right-sided low back pain that is exacerbated by spinal extension. Anteroposterior, lateral, and oblique radiographs of the lumbar spine are completely normal. What is the most appropriate next imaging modality to definitively evaluate for an acute pars interarticularis stress reaction or fracture?

. CT scan of the lumbar spine with reverse gantry angle
. Flexion-extension radiographs of the lumbar spine
. Bone scintigraphy (SPECT)
. MRI of the lumbar spine without contrast
. Diagnostic pars injection under fluoroscopy

Correct Answer & Explanation

. CT scan of the lumbar spine with reverse gantry angle

Explanation

MRI of the lumbar spine, specifically utilizing T2-weighted fat-suppressed or STIR sequences, is now the gold standard and initial imaging of choice for detecting early pars stress reactions (marrow edema) in young athletes with normal plain radiographs. It avoids ionizing radiation compared to CT or SPECT, while providing excellent sensitivity for acute edema.

Question 2592

Topic: 6. Spine

A 13-year-old boy with Duchenne muscular dystrophy is non-ambulatory and has developed a progressive scoliotic curve of 35°. His forced vital capacity (FVC) is 45% of predicted. What is the most appropriate management for his spinal deformity?

. Observation with serial radiographs every 6 months
. Continuous wear of a custom Thoracolumbosacral orthosis (TLSO)
. Posterior spinal fusion from the upper thoracic spine to the pelvis
. Insertion of magnetically controlled growing rods (MCGR)
. Anterior spinal fusion and instrumentation

Correct Answer & Explanation

. Observation with serial radiographs every 6 months

Explanation

In Duchenne muscular dystrophy, scoliosis rapidly progresses once the patient becomes wheelchair-bound. Bracing is contraindicated as it is ineffective and restricts already compromised pulmonary function. Surgery (posterior spinal fusion from the upper thoracic spine to the pelvis) is recommended for curves >20-30 degrees while pulmonary function is still adequate (FVC >35-40%) to minimize perioperative pulmonary complications.

Question 2593

Topic: 6. Spine

A 45-year-old man with a known history of ankylosing spondylitis presents to the emergency department after a minor trip and fall. He complains of moderate neck pain. He is neurologically intact. Cross-table lateral radiographs of the cervical spine are difficult to interpret due to extensive syndesmophytes and overlapping shoulder anatomy, but the resident interprets them as 'negative for acute fracture'. What is the most appropriate next step in management?

. Discharge with a soft collar and NSAIDs
. Flexion-extension radiographs of the cervical spine
. CT scan of the cervical spine
. MRI of the cervical spine with and without contrast
. Discharge with physical therapy for range of motion

Correct Answer & Explanation

. Discharge with a soft collar and NSAIDs

Explanation

Patients with ankylosing spondylitis have highly rigid, osteoporotic spines that are extremely susceptible to unstable fractures (e.g., through the disc space or vertebral body) even after trivial trauma. Plain radiographs are notoriously unreliable and often miss these fractures due to the altered anatomy and osteopenia. A CT scan of the entire cervical spine is mandatory in any AS patient with neck pain following trauma.

Question 2594

Topic: 6. Spine

A 28-year-old woman is involved in a motor vehicle collision and sustains a traumatic spondylolisthesis of C2 (Hangman's fracture). Imaging demonstrates severe angulation of C2 on C3 and 2 mm of anterior translation. The mechanism is determined to be flexion-distraction, classifying this as a Levine-Edwards Type IIA fracture. What is a critical principle regarding the initial non-operative management of this specific injury pattern?

. Application of cervical skeletal traction is indicated to achieve reduction
. Application of cervical skeletal traction is absolutely contraindicated
. Immediate anterior C2-C3 discectomy and fusion is the only treatment
. The patient must be immobilized in hyper-extension in a halo vest immediately
. A rigid cervical collar is sufficient for definitive treatment without reduction

Correct Answer & Explanation

. Application of cervical skeletal traction is indicated to achieve reduction

Explanation

A Levine-Edwards Type IIA Hangman's fracture is characterized by severe angulation with minimal translation, caused by flexion-distraction. Because the C2-C3 disc space is disrupted and highly unstable in distraction, the application of cervical skeletal traction is absolutely contraindicated, as it can cause catastrophic over-distraction and neurologic injury. Reduction is achieved with gentle compression and extension under fluoroscopy, typically followed by halo immobilization.

Question 2595

Topic: 6. Spine

A 15-year-old boy presents with an acute onset of severe lower back pain radiating down his posterior right leg, accompanied by a noticeable left-sided trunk shift. He reports the pain worsens with sitting and coughing. Standing radiographs reveal a right-sided lumbar scoliosis of 20° without pedicle rotation. What is the most likely underlying etiology of this deformity?

. Adolescent idiopathic scoliosis
. Osteoid osteoma of the L4 vertebra
. Lumbar disc herniation
. Spondylolysis
. Tethered cord syndrome

Correct Answer & Explanation

. Adolescent idiopathic scoliosis

Explanation

The patient is presenting with 'sciatic scoliosis', a non-structural functional scoliosis caused by muscle spasm secondary to nerve root irritation from a lumbar disc herniation. Characteristics include an acute onset, severe radicular pain, and a lack of vertebral rotation on radiographs (differentiating it from structural AIS). An osteoid osteoma typically causes a concave curve towards the lesion side and nocturnal pain relieved by NSAIDs.

Question 2596

Topic: 6. Spine

When evaluating a patient with a metastatic spinal lesion, the Spinal Instability Neoplastic Score (SINS) is utilized to assess the need for surgical stabilization. Which of the following individual findings contributes the highest number of points (greatest instability) to the SINS score?

. Blastic appearance of the bone lesion
. Occasional pain not related to movement or posture
. Location in the rigid thoracic spine (T3-T10)
. > 50% collapse of the vertebral body
. Intact posterolateral elements bilaterally

Correct Answer & Explanation

. Blastic appearance of the bone lesion

Explanation

The SINS score assesses 6 components: location, pain, bone lesion, radiographic spinal alignment, vertebral body collapse, and posterolateral involvement. A vertebral body collapse of >50% assigns 3 points (the maximum for that category). Location in a junctional region gives 3 points (rigid spine gets 0 points). Mechanical pain gives 3 points. Lytic lesions give 2 points (blastic gives 0). Bilateral posterolateral involvement gives 3 points.

Question 2597

Topic: 6. Spine

A 42-year-old man presents to the emergency department complaining of severe 10/10 low back pain and bilateral sciatica for the past 24 hours. He is anxious and reports 'saddle' numbness. Which of the following clinical findings is widely considered the most sensitive and earliest indicator of cauda equina syndrome?

. Absent bilateral Achilles reflexes
. Fecal incontinence
. Unilateral foot drop
. Urinary retention with elevated post-void residual
. Decreased anal sphincter tone

Correct Answer & Explanation

. Absent bilateral Achilles reflexes

Explanation

Urinary retention (often resulting in overflow incontinence and a markedly elevated post-void residual volume) is the most consistent, sensitive, and earliest sign of cauda equina syndrome. While decreased anal sphincter tone and perineal numbness are classic, the absence of urinary retention makes the diagnosis of CES highly unlikely.

Question 2598

Topic: 6. Spine

A 75-year-old woman with a T-score of -3.2 undergoes balloon kyphoplasty for a painful osteoporotic compression fracture of L1. Postoperatively, she experiences immediate pain relief. Over the next year, she remains at the highest risk for developing which of the following specific complications related to the treated level?

. Symptomatic pulmonary cement embolism
. Deep surgical site infection
. Compression fracture of the adjacent T12 or L2 vertebrae
. Delayed spinal cord injury from cement migration
. Malignant transformation of the vertebral body

Correct Answer & Explanation

. Symptomatic pulmonary cement embolism

Explanation

Following vertebroplasty or kyphoplasty for osteoporotic compression fractures, patients are at a significantly increased risk of developing new compression fractures in the adjacent untreated vertebrae (e.g., T12 or L2). The rigid cement-augmented vertebra creates a stress riser against the adjacent severely osteoporotic bone.

Question 2599

Topic: 6. Spine

A 35-year-old man is brought to the trauma bay after a high-speed rollover motor vehicle collision. He complains of severe neck pain and numbness in his right thumb. Lateral cervical spine radiographs show C5 is translated anteriorly over C6 by approximately 25% of the vertebral body width. The facet joints at C5-C6 demonstrate a 'bowtie' or 'batwing' sign. What is the most likely diagnosis?

. Bilateral facet dislocation
. Unilateral facet dislocation
. Extension teardrop fracture
. Clay shoveler's fracture
. Burst fracture

Correct Answer & Explanation

. Bilateral facet dislocation

Explanation

A unilateral facet dislocation is caused by a flexion-rotation injury. Radiographically, it is characterized by anterior translation of < 50% of the vertebral body width (whereas bilateral facet dislocation is > 50%). The rotational component causes the facet pillars of the dislocated vertebra to appear out of phase on the lateral view, creating the classic 'bowtie' or 'batwing' sign.

Question 2600

Topic: 6. Spine

A 14-year-old girl is undergoing posterior spinal fusion for adolescent idiopathic scoliosis. During the curve correction maneuver, the anesthesiologist reports a 60% decrease in motor evoked potentials (MEP) amplitude in the bilateral lower extremities. Somatosensory evoked potentials (SSEP) are unchanged. Blood pressure is 110/70 mmHg, and temperature is 36.8°C. The surgeon pauses the procedure and asks the anesthesiologist to review the medication regimen. Which of the following anesthetic agents is most likely contributing to the loss of MEP signals while sparing SSEPs?

. Propofol
. Ketamine
. Dexmedetomidine
. Sevoflurane
. Fentanyl

Correct Answer & Explanation

. Propofol

Explanation

Inhalational halogenated anesthetics (like sevoflurane, isoflurane, desflurane) cause a dose-dependent decrease in amplitude and increase in latency of both SSEPs and MEPs, but MEPs are exquisitely sensitive to these agents. Nitrous oxide also significantly depresses MEPs. Intravenous anesthetics (TIVA), such as propofol, opioids (fentanyl), and ketamine, have much less effect on MEPs and are preferred during spine surgery requiring neuromonitoring. Dexmedetomidine does not significantly depress MEPs at clinical doses.

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