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6. Spine MCQs

Practice Set 201 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 4001

Topic: 6. Spine

A 65-year-old woman with L4-L5 degenerative spondylolisthesis and severe spinal stenosis has failed six months of conservative management. She complains of severe neurogenic claudication and mechanical back pain. What is the most appropriate surgical treatment?

. Laminectomy alone
. Anterior lumbar interbody fusion (ALIF) alone
. Laminectomy and instrumented posterolateral fusion
. Lumbar microdiscectomy
. Insertion of an interspinous process spacer

Correct Answer & Explanation

. Laminectomy and instrumented posterolateral fusion

Explanation

For symptomatic degenerative spondylolisthesis with spinal stenosis, laminectomy with instrumented posterolateral fusion provides superior long-term clinical outcomes compared to laminectomy alone. Decompression alone without stabilization often leads to progressive instability and recurrent symptoms.

Question 4002

Topic: 6. Spine

A 22-year-old man presents with severe neck pain after a rugby tackle. Radiographs reveal a unilateral facet dislocation at C5-C6. What is the classic mechanism of injury responsible for this specific pathology?

. Flexion-distraction
. Flexion-rotation
. Extension-compression
. Pure axial loading
. Hyperextension

Correct Answer & Explanation

. Flexion-rotation

Explanation

Unilateral facet dislocations of the cervical spine typically result from a flexion-rotation mechanism, causing asymmetric disruption of the posterior ligamentous complex and facet joint capsule. In contrast, bilateral facet dislocations are typically caused by pure, severe flexion-distraction forces.

Question 4003

Topic: 6. Spine

A 60-year-old man with a known history of advanced ankylosing spondylitis presents to the emergency department complaining of new, severe neck pain after tripping and falling onto a carpeted floor. Initial plain radiographs of the cervical spine are interpreted as negative. What is the most appropriate next step in management?

. Discharge the patient with NSAIDs and physical therapy
. Prescribe a soft cervical collar and follow up in 2 weeks
. Obtain an urgent CT or MRI of the cervical spine
. Perform dynamic flexion-extension radiographs immediately
. Administer an epidural steroid injection

Correct Answer & Explanation

. Obtain an urgent CT or MRI of the cervical spine

Explanation

Patients with ankylosing spondylitis possess a rigid, osteopenic spine that acts like a long bone, making them highly susceptible to unstable fractures even from trivial trauma. Occult fractures are common and can lead to devastating epidural hematomas or cord injury, making advanced imaging (CT or MRI) mandatory when plain films are negative.

Question 4004

Topic: 6. Spine

A 45-year-old man presents with acute onset right leg pain that radiates down the lateral aspect of his calf to the dorsum of his foot. MRI reveals a large paracentral disc herniation at the L4-L5 level. Which nerve root is most likely compressed, and what is the expected motor deficit?

. L4; weakness in ankle dorsiflexion
. L4; weakness in knee extension
. L5; weakness in extensor hallucis longus
. S1; weakness in ankle plantarflexion
. L5; weakness in hip flexion

Correct Answer & Explanation

. L5; weakness in extensor hallucis longus

Explanation

In the lumbar spine, a paracentral disc herniation typically compresses the traversing nerve root at that level. An L4-L5 herniation compresses the L5 nerve root, which classically causes weakness in the extensor hallucis longus (great toe extension) and altered sensation over the dorsum of the foot.

Question 4005

Topic: 6. Spine
An 8-year-old boy is brought to the ED after a motor vehicle collision. He had transient numbness and weakness in both legs that has since resolved. Plain radiographs and a non-contrast CT of the spine are completely normal. What is the diagnostic modality of choice to fully evaluate this clinical picture?
. Repeat CT scan in 48 hours
. Dynamic flexion-extension fluoroscopy
. MRI of the spinal cord
. Somatosensory evoked potentials (SSEPs)
. CT myelography

Correct Answer & Explanation

. MRI of the spinal cord

Explanation

The patient is exhibiting signs of Spinal Cord Injury Without Radiographic Abnormality (SCIWORA), which is most common in pediatric patients due to inherent ligamentous laxity. MRI is the gold standard for detecting spinal cord edema, hemorrhage, or subtle ligamentous injury not visible on CT or plain films.

Question 4006

Topic: 6. Spine

A 62-year-old woman underwent an L4-S1 posterior spinal instrumented fusion 5 years ago. She now presents with new-onset radicular leg pain and progressive low back pain. Radiographs show significant degenerative changes and stenosis at the L3-L4 level. Which biomechanical factor is the primary contributor to this new pathology?

. Use of titanium instead of PEEK rods during the index surgery
. Increased motion and biomechanical stress at the unfused segments
. Progression of underlying systemic osteoporosis
. Placement of interbody cages at the fused levels
. Subclinical, indolent postoperative infection

Correct Answer & Explanation

. Increased motion and biomechanical stress at the unfused segments

Explanation

Adjacent segment disease occurs as a result of the loss of motion at the surgically fused levels. This leads to compensatory hypermobility and increased biomechanical shear stresses at the adjacent unfused segments, thereby accelerating their degeneration.

Question 4007

Topic: 6. Spine

A 45-year-old man with a history of chronic low back pain suddenly develops severe bilateral sciatica, saddle anesthesia, and urinary retention. Physical examination reveals decreased rectal tone. What is the most critical and definitive step in his management?

. Administration of high-dose intravenous dexamethasone
. Immediate diagnostic lumbar puncture
. Urgent MRI of the lumbar spine followed by emergent surgical decompression
. Formal urodynamic testing to confirm neurogenic bladder
. Urgent translaminar epidural steroid injection

Correct Answer & Explanation

. Urgent MRI of the lumbar spine followed by emergent surgical decompression

Explanation

This patient presents with classic signs of Cauda Equina Syndrome, an absolute orthopedic emergency. The definitive management is an urgent MRI to confirm the diagnosis followed by emergent surgical decompression (typically within 24-48 hours) to prevent permanent neurological deficits.

Question 4008

Topic: 6. Spine

A 28-year-old unrestrained driver is involved in a head-on collision. Radiographs demonstrate bilateral fractures through the pars interarticularis of the C2 vertebra with mild anterior subluxation of C2 on C3. What is the classic mechanism of injury for this specific fracture pattern?

. Hyperextension and axial loading
. Pure hyperflexion
. Flexion-distraction
. Lateral bending and rotation
. Hyperflexion and axial loading

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

Traumatic spondylolisthesis of the axis (Hangman's fracture) classically results from sudden hyperextension and axial loading, commonly seen in unrestrained motor vehicle accidents when the chin strikes the dashboard. This leads to bilateral fractures through the pars interarticularis.

Question 4009

Topic: 6. Spine

A 35-year-old pedestrian is struck by a vehicle and sustains a severe traumatic brain injury. Lateral cervical spine radiographs demonstrate a basion-dental interval (BDI) of 14 mm. Which of the following initial stabilization techniques is strictly contraindicated in this patient?

. Application of a hard cervical collar
. Placement of cervical traction
. Immobilization with sandbags and tape
. Placement on a rigid spine board
. Manual in-line stabilization

Correct Answer & Explanation

. Placement of cervical traction

Explanation

A basion-dental interval (BDI) > 12 mm indicates an atlanto-occipital dissociation, a highly unstable, life-threatening ligamentous disruption. Cervical traction is absolutely contraindicated because it can cause severe over-distraction, leading to catastrophic stretching of the brainstem and spinal cord.

Question 4010

Topic: 6. Spine

A 68-year-old man presents with a 2-year history of bilateral buttock and leg pain that worsens with walking and standing. He reports that leaning forward on a shopping cart relieves his symptoms. Which of the following physical examination findings is most likely to be present in this patient?

. Diminished pedal pulses
. Pain reproduced with lumbar flexion
. Pain reproduced with lumbar extension
. Positive straight leg raise test
. Hyperreflexia at the knees and ankles

Correct Answer & Explanation

. Pain reproduced with lumbar extension

Explanation

Neurogenic claudication from lumbar spinal stenosis is typically exacerbated by lumbar extension, which further narrows the spinal canal and neural foramina. Flexion increases the canal diameter, thereby providing symptom relief.

Question 4011

Topic: 6. Spine

A 65-year-old man presents with progressive hand clumsiness and difficulty walking. Examination shows hyperreflexia in the lower extremities, a positive Hoffman's sign, and a wide-based gait. MRI reveals severe cervical stenosis from C3 to C6 with T2 signal change in the spinal cord, and a fixed cervical kyphosis of 15 degrees. What is the most appropriate surgical management?

. Cervical laminectomy
. Cervical laminoplasty
. Anterior cervical discectomy and fusion (ACDF) or corpectomy
. Posterior lateral mass screw fixation without decompression
. Cervical disc arthroplasty

Correct Answer & Explanation

. Anterior cervical discectomy and fusion (ACDF) or corpectomy

Explanation

Posterior decompression alone (laminectomy or laminoplasty) is contraindicated in the setting of fixed cervical kyphosis as the cord will not drift backward away from anterior compression. An anterior approach (ACDF or corpectomy) allows for direct decompression of the anterior pathology and correction of the kyphotic deformity.

Question 4012

Topic: 6. Spine

A 45-year-old man falls from a height and sustains an L1 burst fracture. He is neurologically intact. CT and MRI show 15 degrees of kyphosis, 30% canal compromise, and an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the most appropriate management?

. Short segment posterior spinal fusion
. Anterior corpectomy and fusion
. Thoracolumbosacral orthosis (TLSO) brace
. Laminectomy alone
. Long segment posterior spinal fusion

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) brace

Explanation

The patient has a TLICS score of 2 (1 point for compression/burst morphology, 0 points for intact neurology, 0 points for intact PLC). A score of 3 or less indicates non-operative management, typically with a TLSO brace and early mobilization.

Question 4013

Topic: Thoracolumbar Spine & Deformity

A 72-year-old woman is planning to undergo reconstructive surgery for adult spinal deformity. To achieve optimal sagittal balance and minimize the risk of adjacent segment disease, her postoperative lumbar lordosis (LL) should be matched to which of the following pelvic parameters?

. Pelvic tilt
. Sacral slope
. Pelvic incidence
. Sagittal vertical axis
. T1 pelvic angle

Correct Answer & Explanation

. Pelvic incidence

Explanation

Pelvic incidence (PI) is a fixed morphologic parameter that dictates a patient's optimal spino-pelvic alignment. To achieve optimal sagittal balance, the postoperative lumbar lordosis (LL) should typically be within 10 degrees of the patient's pelvic incidence (PI - LL < 10 degrees).

Question 4014

Topic: 6. Spine

A 55-year-old man presents with right leg pain and weakness. Examination reveals 3/5 strength in right knee extension and a diminished right patellar reflex. Sensation is decreased over the medial aspect of the lower leg. An MRI shows a far-lateral disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

A far-lateral (extraforaminal) disc herniation at L4-L5 compresses the exiting L4 nerve root, unlike a paracentral herniation which affects the traversing L5 root. An L4 radiculopathy presents with weakness in knee extension (quadriceps) and a diminished patellar reflex.

Question 4015

Topic: 6. Spine

In the treatment of acute traumatic cervical bilateral facet dislocations in an awake, alert, and cooperative patient without distracting injuries, what is the most appropriate initial management step?

. Immediate MRI of the cervical spine
. Closed reduction via awake cranial traction
. Emergent posterior cervical fusion
. Emergent anterior cervical discectomy and fusion
. Application of a halo vest

Correct Answer & Explanation

. Closed reduction via awake cranial traction

Explanation

For awake, alert, and neurologically evaluable patients with cervical facet dislocations, the current standard of care is immediate closed reduction using cranial traction. An MRI prior to reduction delays treatment and is not necessary unless the patient is unexaminable or fails closed reduction.

Question 4016

Topic: Thoracolumbar Spine & Deformity

A 25-year-old man sustains a seatbelt-type injury in a high-speed motor vehicle collision. Radiographs demonstrate a flexion-distraction (Chance) fracture of L2. Which of the following associated injuries must be carefully evaluated for?

. Traumatic aortic rupture
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture
. Renal artery thrombosis
. Splenic rupture

Correct Answer & Explanation

. Intra-abdominal hollow viscus injury

Explanation

Chance fractures (flexion-distraction injuries) are classically associated with lap seatbelt use in motor vehicle collisions. There is a high incidence (up to 40%) of concomitant intra-abdominal injuries, most commonly hollow viscus perforations.

Question 4017

Topic: 6. Spine

A 68-year-old man with a long-standing history of ankylosing spondylitis presents to the emergency department with severe neck pain after a minor fall from a standing height. Neurologic examination is normal. Initial standard AP and lateral cervical spine radiographs appear unremarkable. What is the next best step in management?

. Discharge with a soft cervical collar
. Flexion and extension cervical radiographs
. CT scan of the entire cervical spine
. Electromyography (EMG)
. Immediate halo vest application

Correct Answer & Explanation

. CT scan of the entire cervical spine

Explanation

Patients with ankylosing spondylitis have highly rigid spines that are susceptible to unstable "chalk-stick" fractures even from trivial trauma. Occult fractures are common on plain radiographs, making a CT or MRI of the entire spine mandatory if there is any clinical suspicion.

Question 4018

Topic: 6. Spine

A 60-year-old woman presents with classic symptoms of neurogenic claudication. MRI shows severe lumbar spinal stenosis at L4-L5. Which of the following anatomic structures is the primary contributor to dorsal compression of the dural sac in this condition?

. Herniated nucleus pulposus
. Hypertrophic ligamentum flavum
. Ossified posterior longitudinal ligament
. Spondylolisthesis of the vertebral body
. Facet joint osteophytes

Correct Answer & Explanation

. Hypertrophic ligamentum flavum

Explanation

Degenerative lumbar spinal stenosis is caused by disc space narrowing, facet hypertrophy, and ligamentum flavum hypertrophy. The hypertrophic ligamentum flavum buckles inward, causing the primary dorsal compression of the thecal sac.

Question 4019

Topic: 6. Spine

A 45-year-old diabetic patient presents with 2 weeks of worsening back pain, fever, and new-onset weakness in the lower extremities. Laboratory markers show elevated ESR and CRP. MRI reveals L3-L4 discitis/osteomyelitis with a ventral epidural abscess compressing the cauda equina. What is the most appropriate next step?

. CT-guided needle biopsy and broad-spectrum antibiotics
. Empiric IV antibiotics and bracing
. Emergent surgical decompression and debridement
. Administration of high-dose dexamethasone
. Outpatient physical therapy and oral antibiotics

Correct Answer & Explanation

. Emergent surgical decompression and debridement

Explanation

The patient has a spinal epidural abscess with new-onset neurologic deficits (lower extremity weakness). This is a surgical emergency requiring immediate decompression and debridement to prevent permanent neurologic injury.

Question 4020

Topic: 6. Spine

A 65-year-old man undergoes a multi-level posterior cervical laminectomy and fusion (C3-C7) for cervical spondylotic myelopathy. On postoperative day 2, he develops isolated weakness in right shoulder abduction and external rotation (strength 2/5). His preoperative strength was normal, and long-tract signs are absent. What is the most likely diagnosis?

. C4 radiculopathy
. C5 palsy
. Postoperative epidural hematoma
. Iatrogenic spinal cord injury
. Brachial plexopathy

Correct Answer & Explanation

. C5 palsy

Explanation

Postoperative C5 palsy is a well-known complication after cervical decompression, presenting as isolated deltoid and/or biceps weakness. It is thought to be caused by posterior drift of the spinal cord resulting in traction on the short, horizontally oriented C5 nerve roots.

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