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6. Spine MCQs

Practice Set 196 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 3901

Topic: 6. Spine

A 45-year-old man presents with right leg pain, numbness over the dorsum of his foot, and weakness in great toe extension. MRI shows a paracentral disc herniation. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

Weakness in the extensor hallucis longus (EHL) and numbness over the dorsum of the foot are classic signs of an L5 radiculopathy. In the lumbar spine, a paracentral disc herniation at L4-L5 typically compresses the traversing L5 nerve root.

Question 3902

Topic: 6. Spine

A 22-year-old man arrives in the trauma bay after a diving accident. He is awake, alert, and cooperative. He has no movement or sensation below the C6 level. Plain films show a unilateral facet dislocation at C5-C6. What is the most appropriate next step in management?

. Immediate MRI of the cervical spine
. Closed reduction with cranial traction
. Anterior cervical discectomy and fusion
. Posterior cervical fusion
. High-dose methylprednisolone protocol

Correct Answer & Explanation

. Closed reduction with cranial traction

Explanation

In an awake, alert, and testable patient with a cervical spine dislocation and a neurologic deficit, immediate closed reduction with cranial traction is indicated to decompress the spinal cord. An MRI is not required prior to reduction in an awake, reliable patient.

Question 3903

Topic: 6. Spine

A 68-year-old man with ankylosing spondylitis presents to the ED with neck pain after a minor low-speed motor vehicle collision.

Neurologic examination is normal. Initial AP and lateral cervical spine radiographs show no obvious fracture. What is the next most appropriate step?

. Discharge with a soft cervical collar and NSAIDs
. Reassure the patient and discharge to physical therapy
. Obtain flexion-extension cervical radiographs
. Obtain a CT scan of the entire cervical spine
. Schedule an outpatient MRI within 2 weeks

Correct Answer & Explanation

. Obtain a CT scan of the entire cervical spine

Explanation

Patients with ankylosing spondylitis are at a high risk for highly unstable extension fractures, which are often occult on plain radiographs, even after minor trauma. A CT scan of the spine is mandatory to rule out fractures and epidural hematomas.

Question 3904

Topic: 6. Spine

A 60-year-old woman underwent a primary L4-L5 microdiscectomy 6 months ago. She was symptom-free for 5 months but now presents with recurrent, severe right-sided L5 radiculopathy failing 6 weeks of conservative treatment. MRI shows a recurrent focal disc extrusion at L4-L5. What is the recommended surgical intervention?

. L4-L5 transforaminal lumbar interbody fusion (TLIF)
. L4-L5 anterior lumbar interbody fusion (ALIF)
. Revision L4-L5 microdiscectomy
. Laminectomy without discectomy
. Spinal cord stimulator trial

Correct Answer & Explanation

. Revision L4-L5 microdiscectomy

Explanation

For a first-time recurrent disc herniation presenting primarily with radicular pain and no mechanical back pain or gross instability, revision microdiscectomy is the procedure of choice. Fusion is reserved for instability, mechanical back pain, or multiple recurrences.

Question 3905

Topic: 6. Spine

Which of the following congenital spinal anomalies has the highest risk of rapid deformity progression, nearly always requiring early surgical intervention?

. Fully segmented hemivertebra
. Incarcerated hemivertebra
. Unilateral unsegmented bar
. Unilateral unsegmented bar with a contralateral hemivertebra
. Block vertebra

Correct Answer & Explanation

. Unilateral unsegmented bar with a contralateral hemivertebra

Explanation

A unilateral unsegmented bar combined with a contralateral hemivertebra creates a massive growth mismatch, leading to rapid and severe deformity progression. Early surgical intervention (e.g., fusion or hemivertebra excision) is typically required to prevent severe curvature.

Question 3906

Topic: 6. Spine
A 75-year-old man with known cervical spinal stenosis falls forward, striking his forehead. He presents with severe weakness in his bilateral hands and arms, but is able to move his legs against gravity. Proprioception and pain sensation are diminished distally. What is the most likely diagnosis?
. Anterior cord syndrome
. Central cord syndrome
. Brown-Sรฉquard syndrome
. Posterior cord syndrome
. Cruciate paralysis

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs after a hyperextension injury in a patient with pre-existing cervical stenosis. It is characterized by disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 3907

Topic: 6. Spine

A 65-year-old man presents with progressive clumsiness in his hands and a wide-based gait. Physical exam shows a positive Hoffman's sign and hyperreflexia. MRI of the cervical spine is ordered. Which of the following MRI findings is the strongest independent predictor of a poor surgical outcome after decompression for degenerative cervical myelopathy?

. T2 hyperintensity within the spinal cord
. T1 hypointensity within the spinal cord
. Severe decrease in the anteroposterior canal diameter
. Presence of an ossified posterior longitudinal ligament
. Multilevel facet joint hypertrophy

Correct Answer & Explanation

. T1 hypointensity within the spinal cord

Explanation

T1 hypointensity in the spinal cord indicates myelomalacia and cystic necrosis, representing irreversible cord damage. While T2 hyperintensity represents edema or gliosis, T1 changes correlate strongly with poor postoperative neurological recovery.

Question 3908

Topic: 6. Spine



A 55-year-old man with long-standing ankylosing spondylitis falls and sustains an undisplaced C6-C7 fracture seen on initial CT. He is neurologically intact on presentation. Twelve hours later, he develops progressive bilateral lower extremity weakness. What is the most likely cause of his delayed neurological deterioration?

. Vertebral artery dissection
. Post-traumatic epidural hematoma
. Unrecognized pre-existing epidural abscess
. Ischemic spinal cord edema
. Progressive kyphotic angulation

Correct Answer & Explanation

. Post-traumatic epidural hematoma

Explanation

Patients with an ankylosed spine are at extremely high risk for epidural hematomas following even minor trauma due to altered biomechanics and tearing of the epidural venous plexus. Prompt MRI is indicated for any delayed neurological deficit to rule out this reversible cause.

Question 3909

Topic: 6. Spine

Degenerative spondylolisthesis in the lumbar spine most commonly occurs at the L4-L5 level. Which of the following anatomic variations is most strongly associated with the development of this specific condition?

. Coronal orientation of the facet joints
. Sagittal orientation of the facet joints
. Congenitally short pedicles
. Spina bifida occulta
. Lumbarization of the S1 vertebra

Correct Answer & Explanation

. Sagittal orientation of the facet joints

Explanation

A more sagittal orientation of the L4-L5 facet joints provides less bony resistance to anterior shear forces compared to coronally oriented facets. This predisposes the segment to excessive anterior translation as the disc degenerates.

Question 3910

Topic: Cervical Spine

A 72-year-old man presents with an isolated Type II odontoid fracture after a ground-level fall. Anterior odontoid screw fixation is being considered. Which of the following is an absolute contraindication to this specific procedure?

. Patient age greater than 65 years
. Concomitant posterior C1 ring fracture
. Transverse ligament rupture
. Fracture displacement greater than 2 mm
. Anteroinferior to posterosuperior fracture line (reverse obliquity)

Correct Answer & Explanation

. Transverse ligament rupture

Explanation

Anterior screw fixation depends on an intact transverse ligament to provide stability to the C1-C2 articulation; its rupture is an absolute contraindication. A reverse obliquity fracture pattern is also a classic contraindication as the screw trajectory causes fracture distraction.

Question 3911

Topic: 6. Spine

In adult spinal deformity surgery, achieving optimal sagittal balance is critical to prevent hardware failure and adjacent segment disease. If a patient has a measured Pelvic Incidence (PI) of 58 degrees, what is the ideal postoperative target for Lumbar Lordosis (LL)?

. 30 degrees
. 40 degrees
. 50 degrees
. 60 degrees
. 70 degrees

Correct Answer & Explanation

. 60 degrees

Explanation

The generally accepted goal for sagittal balance in adult spinal deformity is achieving a Pelvic Incidence minus Lumbar Lordosis (PI-LL) mismatch of less than 10 degrees. Therefore, a target LL of approximately 58-60 degrees is ideal for a PI of 58.

Question 3912

Topic: 6. Spine

A 68-year-old man with underlying cervical spondylosis presents after a hyperextension injury. Examination reveals 2/5 motor strength in his upper extremities and 4/5 strength in his lower extremities. The disproportionate upper extremity weakness is primarily due to the anatomic arrangement of which spinal tract?

. Dorsal columns
. Spinothalamic tract
. Lateral corticospinal tract
. Rubrospinal tract
. Vestibulospinal tract

Correct Answer & Explanation

. Lateral corticospinal tract

Explanation

Central cord syndrome preferentially affects the upper extremities because the cervical motor fibers within the lateral corticospinal tract are located medially, closer to the central canal. Lumbar and sacral fibers are situated more laterally and are thus spared.

Question 3913

Topic: Thoracolumbar Spine & Deformity

A 65-year-old woman presents with severe back pain, forward-leaning posture, and difficulty standing upright. Radiographs reveal adult spinal deformity. Her pelvic incidence (PI) is 60 degrees. To achieve a harmonious sagittal alignment postoperatively, what is the ideal target for her lumbar lordosis (LL)?

. LL should be exactly equal to her Pelvic Tilt (PT)
. LL should be within 10 degrees of her Pelvic Incidence (PI)
. LL should be 20 degrees greater than her PI
. LL should be matched to her Sacral Slope (SS) minus 10 degrees
. LL should be independent of PI, targeting 40 degrees for all adults

Correct Answer & Explanation

. LL should be within 10 degrees of her Pelvic Incidence (PI)

Explanation

For optimal sagittal balance in adult spinal deformity, the lumbar lordosis (LL) should be within 10 degrees of the pelvic incidence (PI). A PI-LL mismatch > 10 degrees is associated with poor health-related quality of life outcomes and adjacent segment disease.

Question 3914

Topic: Cervical Spine

An 82-year-old man presents with neck pain after a low-speed motor vehicle collision. CT scan of the cervical spine demonstrates a displaced Type II odontoid fracture. He is neurologically intact but has significant medical comorbidities. Which of the following is the most appropriate initial management?

. Rigid cervical collar
. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 fusion
. Cervical traction followed by Minerva cast

Correct Answer & Explanation

. Rigid cervical collar

Explanation

In elderly patients (typically >80 years) with significant comorbidities, a rigid cervical collar is often preferred as initial treatment for Type II odontoid fractures. Surgery carries high morbidity, and halo vest immobilization has an unacceptably high complication and mortality rate in this age group.

Question 3915

Topic: 6. Spine

A 60-year-old man undergoes a posterior C3-C6 laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 2, he develops isolated right deltoid and biceps weakness (grade 2/5) without sensory deficits or lower extremity changes. What is the most likely etiology?

. Epidural hematoma
. C5 nerve root tethering/palsy
. Inadequate spinal cord decompression
. Spinal cord contusion during intubation
. Hardware failure with screw back-out

Correct Answer & Explanation

. C5 nerve root tethering/palsy

Explanation

C5 palsy is a well-known complication after cervical decompression (especially posterior laminectomy and fusion), occurring in up to 5-10% of cases. It is thought to result from spinal cord drift and subsequent tethering of the short C5 nerve roots.

Question 3916

Topic: 6. Spine
A 45-year-old man presents with progressive lower extremity weakness and myelopathy. MRI reveals a large, calcified central disc herniation at T8-T9 causing severe cord compression. Which of the following surgical approaches is contraindicated?
. Costotransversectomy
. Anterior thoracotomy and diskectomy
. Posterior laminectomy and diskectomy
. Lateral extracavitary approach
. Video-assisted thoracoscopic surgery (VATS)

Correct Answer & Explanation

. Posterior laminectomy and diskectomy

Explanation

Posterior laminectomy for a central thoracic disc herniation is strictly contraindicated due to the high risk of catastrophic spinal cord injury. Accessing a central thoracic disc requires an anterior, lateral, or posterolateral approach to avoid manipulating the thoracic cord.

Question 3917

Topic: Thoracolumbar Spine & Deformity
A 16-year-old boy presents with back pain and a prominent thoracic kyphosis. Radiographs reveal a thoracic kyphosis of 65 degrees. Which of the following radiographic criteria is required to confirm the diagnosis of Scheuermann's disease?
. At least 3 adjacent vertebrae with 5 degrees of anterior wedging
. At least 2 adjacent vertebrae with 10 degrees of anterior wedging
. Apical vertebral rotation of Grade III
. Interpedicular widening at the apex
. Spondylolysis at L5

Correct Answer & Explanation

. At least 3 adjacent vertebrae with 5 degrees of anterior wedging

Explanation

Sorensen's criteria for classic Scheuermann's kyphosis require the presence of at least 3 adjacent vertebrae, each with a minimum of 5 degrees of anterior wedging. Additional findings often include Schmorl's nodes and irregular endplates.

Question 3918

Topic: 6. Spine

A 68-year-old woman presents with neurogenic claudication and L4 radiculopathy. Imaging demonstrates a L4-L5 degenerative spondylolisthesis with severe central canal and lateral recess stenosis. She has failed 6 months of conservative management. According to the SPORT trial, which of the following statements regarding surgical intervention is true?

. Decompression alone yields superior outcomes to decompression and fusion
. Surgical treatment provides significantly greater improvement in pain and function compared to nonoperative treatment
. Nonoperative treatment is superior to surgery at 4-year follow-up
. The addition of instrumentation to fusion decreases clinical outcomes
. There is no difference in reoperation rates between decompression alone and fusion

Correct Answer & Explanation

. Surgical treatment provides significantly greater improvement in pain and function compared to nonoperative treatment

Explanation

The Spine Patient Outcomes Research Trial (SPORT) demonstrated that patients with degenerative spondylolisthesis and spinal stenosis treated surgically had significantly greater improvement in pain and function compared to those treated nonoperatively.

Question 3919

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast presents with chronic lower back pain. Radiographs reveal a Grade II isthmic spondylolisthesis at L5-S1. She has failed 6 months of bracing and physical therapy. If surgery is performed, what is the most appropriate procedure?

. L5-S1 laminectomy without fusion
. L5 pars defect direct repair
. L5-S1 posterolateral fusion with or without interbody
. L4-S1 posterior instrumented fusion
. Anterior-only L5-S1 interbody fusion without posterior fixation

Correct Answer & Explanation

. L5-S1 posterolateral fusion with or without interbody

Explanation

For a symptomatic Grade II isthmic spondylolisthesis in an adolescent failing conservative care, an in-situ L5-S1 fusion is the standard surgical treatment. Direct pars repair is generally reserved for higher level defects (L1-L4) or L5 defects without significant slip (Grade 0-I).

Question 3920

Topic: 6. Spine

A 65-year-old woman presents with severe low back pain and an inability to stand up straight. Preoperative standing radiographs demonstrate a pelvic incidence (PI) of 60 degrees. To achieve optimal sagittal balance postoperatively and minimize the risk of adjacent segment disease, her lumbar lordosis (LL) should be restored to within what range?

. 10 to 20 degrees
. 30 to 40 degrees
. 50 to 70 degrees
. 70 to 90 degrees
. LL does not correlate with PI in adult spinal deformity

Correct Answer & Explanation

. 10 to 20 degrees

Explanation

In adult spinal deformity, restoring sagittal balance is critical for favorable clinical outcomes. The lumbar lordosis (LL) should match the pelvic incidence (PI) within +/- 10 degrees (PI-LL < 10 degrees).

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