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6. Spine MCQs

Practice Set 371 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 7401

Topic: 6. Spine

A 68-year-old male with known Paget's disease presents with slowly progressive bilateral lower extremity weakness, numbness, and difficulty walking. Radiographs of the lumbar spine show an enlarged, dense vertebral body (ivory vertebra). What is the most likely cause of his neurological symptoms?

. Malignant transformation to osteosarcoma in the spinal canal
. Vascular steal phenomenon due to hypervascular pagetic bone
. Pathologic fracture of the pars interarticularis
. Epidural hematoma secondary to minor trauma
. Spinal stenosis due to osseous enlargement of the pagetic vertebra

Correct Answer & Explanation

. Spinal stenosis due to osseous enlargement of the pagetic vertebra

Explanation

Paget's disease causes cortical thickening and osseous enlargement of the affected bones. In the spine, this expansion can lead to central canal or foraminal stenosis, compressing the spinal cord or nerve roots and causing progressive neurological deficits.

Question 7402

Topic: 6. Spine

A 42-year-old male with end-stage renal disease presents with chronic back pain. Radiographs of the lumbar spine demonstrate dense sclerotic bands at the superior and inferior endplates of the vertebral bodies. This "Rugger-Jersey" spine appearance is a hallmark of which condition?

. Osteopetrosis
. Paget's disease
. Secondary hyperparathyroidism
. Ankylosing spondylitis
. Multiple myeloma

Correct Answer & Explanation

. Secondary hyperparathyroidism

Explanation

The "Rugger-Jersey" spine is characterized by horizontal sclerotic bands adjacent to the vertebral endplates. It is a classic radiographic manifestation of osteosclerosis associated with secondary hyperparathyroidism (renal osteodystrophy).

Question 7403

Topic: 6. Spine

A 45-year-old male presents with foot drop and numbness over the dorsum of his left foot. To clinically differentiate an L5 radiculopathy from a common peroneal nerve palsy, the examiner should test the strength of which of the following muscles?

. Tibialis anterior
. Extensor hallucis longus
. Peroneus longus
. Tibialis posterior
. Extensor digitorum brevis

Correct Answer & Explanation

. Tibialis posterior

Explanation

Correct Answer: DBoth L5 radiculopathy and common peroneal nerve palsy can cause foot drop (weakness of the tibialis anterior and extensor hallucis longus) and numbness over the dorsum of the foot. However, the tibialis posterior muscle is innervated by the tibial nerve but receives its segmental innervation primarily from the L5 nerve root. Therefore, weakness in foot inversion (tibialis posterior function) indicates an L5 radiculopathy, whereas normal inversion strength points to an isolated common peroneal nerve lesion.

Question 7404

Topic: 6. Spine

A 45-year-old male presents with an L5 radiculopathy due to a paracentral disc herniation at L4-L5. Which of the following physical examination findings is most specific for isolating an L5 motor deficit?

. Weakness in ankle plantarflexion
. Weakness in great toe extension
. Diminished patellar reflex
. Diminished Achilles reflex
. Weakness in hip flexion

Correct Answer & Explanation

. Weakness in great toe extension

Explanation

Correct Answer: Weakness in great toe extensionThe L5 nerve root primarily innervates the extensor hallucis longus (EHL), which is responsible for great toe extension. Testing EHL strength is the most specific motor test for L5 radiculopathy. Ankle dorsiflexion (tibialis anterior) is also L5 but has L4 contribution. The Achilles reflex is S1, and the patellar reflex is L4.

Question 7405

Topic: 6. Spine

A 70-year-old man presents with deteriorating handwriting, difficulty buttoning his shirt, and gait instability. Examination reveals a positive Hoffmann sign and hyperreflexia in the lower extremities. Which of the following is the most sensitive imaging modality to assess the primary etiology of his symptoms?

. Upright plain radiographs with flexion/extension views
. Computed tomography (CT) scan without contrast
. Magnetic resonance imaging (MRI) of the cervical spine
. CT myelography
. Somatosensory evoked potentials (SSEP)

Correct Answer & Explanation

. Magnetic resonance imaging (MRI) of the cervical spine

Explanation

Cervical spondylotic myelopathy classically presents with upper extremity dexterity issues and upper motor neuron signs in the lower extremities. MRI is the most sensitive non-invasive imaging modality to visualize spinal cord compression and myelomalacia.

Question 7406

Topic: 6. Spine

A 24-year-old male falls on an outstretched hand and complains of anatomic snuffbox tenderness. Initial radiographs are negative for a fracture. Which of the following is the most appropriate next step in management?

. Reassurance and unrestricted return to activities
. Application of a thumb spica splint and repeat radiographs in 10-14 days
. Immediate open reduction and internal fixation
. Corticosteroid injection into the first dorsal compartment
. MRI of the cervical spine to rule out radiculopathy

Correct Answer & Explanation

. Application of a thumb spica splint and repeat radiographs in 10-14 days

Explanation

Clinical suspicion of a scaphoid fracture with negative initial radiographs warrants immobilization in a thumb spica splint and clinical/radiographic re-evaluation in 10-14 days. Alternatively, advanced imaging such as MRI can be used acutely to rule out a fracture.

Question 7407

Topic: Thoracolumbar Spine & Deformity

A 15-year-old female gymnast presents with progressive lower back pain that worsens with extension. Lateral lumbar radiographs demonstrate a grade II isthmic spondylolisthesis at L5-S1. What is the precise anatomic location of the structural defect causing this condition?

. Pedicle
. Pars interarticularis
. Spinous process
. Lamina
. Superior articular facet

Correct Answer & Explanation

. Pars interarticularis

Explanation

Isthmic spondylolisthesis is characterized by a defect or stress fracture in the pars interarticularis. It is particularly common in adolescent athletes who perform repetitive spinal extension and loading, such as gymnasts and football linemen.

Question 7408

Topic: Cervical Spine

A 25-year-old male sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following an MVC. Imaging shows a bilateral pars fracture with 4 mm of translation and 15 degrees of angulation. According to the Levine and Edwards classification, what is the most appropriate initial management?

. Rigid cervical collar alone
. Halo vest immobilization following gentle traction
. Anterior cervical discectomy and fusion (ACDF)
. Posterior C1-C3 instrumented fusion
. Open reduction and internal fixation of the C2 pars

Correct Answer & Explanation

. Halo vest immobilization following gentle traction

Explanation

This describes a Type II Hangman's fracture (>3 mm translation, >11 degrees angulation) caused by hyperextension and axial loading followed by severe flexion. The initial management is gentle traction to reduce the deformity, followed by halo vest immobilization.

Question 7409

Topic: 6. Spine

A 45-year-old man falls from a roof, sustaining a burst fracture of L1. He has no motor or sensory deficits in his legs, but his post-void residual bladder volume is 800 mL and he has lost voluntary anal sphincter control. This clinical picture is most consistent with injury to which of the following?

. Cervical spinal cord
. Thoracic spinal cord
. Conus medullaris
. Cauda equina
. Lumbar plexus

Correct Answer & Explanation

. Conus medullaris

Explanation

Conus medullaris syndrome typically presents with early, prominent bowel/bladder dysfunction (areflexic bladder) and saddle anesthesia, often with preserved lower extremity motor function. It occurs with injuries near the T12-L1 level where the spinal cord terminates.

Question 7410

Topic: 6. Spine

A 55-year-old male with long-standing ankylosing spondylitis presents with new-onset neck pain after a minor low-energy fall. His neurological exam is currently intact, and initial cervical radiographs are unrevealing.

What is the most appropriate next step in management?

. Discharge with a soft cervical collar and NSAIDs
. CT scan of the cervical spine
. Flexion and extension cervical radiographs
. Cervical epidural steroid injection
. Immediate awake fiberoptic intubation

Correct Answer & Explanation

. CT scan of the cervical spine

Explanation

Patients with ankylosing spondylitis have a highly rigid spine, making them susceptible to unstable fractures even from minor trauma. A CT scan is the standard of care for initial evaluation as plain radiographs frequently miss these fractures due to altered anatomy and osteopenia.

Question 7411

Topic: 6. Spine

A 45-year-old man with a history of ankylosing spondylitis presents to the emergency department after a low-energy fall. He reports new-onset neck pain but no neurologic deficits. Radiographs demonstrate an undisplaced fracture through the C5-C6 disc space. What is the most appropriate management?

. Soft collar for 6 weeks
. Non-operative management with rigid collar
. Posterior cervical instrumentation and fusion extending multiple levels
. Stand-alone anterior plate fixation
. Anterior odontoid screw

Correct Answer & Explanation

. Posterior cervical instrumentation and fusion extending multiple levels

Explanation

Fractures in ankylosing spondylitis are often highly unstable 'chalk-stick' fractures that can displace catastrophically. They require rigid stabilization, typically with long-segment posterior instrumentation, even if initially undisplaced.

Question 7412

Topic: 6. Spine

A 35-year-old male with advanced ankylosing spondylitis presents with progressive chin-on-chest deformity impairing his horizontal gaze. Preoperative evaluation determines that an extension osteotomy of the cervical spine is necessary. At which anatomical level is this osteotomy most safely and commonly performed?

. C1-C2
. C3-C4
. C5-C6
. C7-T1
. T3-T4

Correct Answer & Explanation

. C7-T1

Explanation

Cervicothoracic extension osteotomies for correcting chin-on-chest deformity in AS are most safely performed at the C7-T1 level. This location has a wider spinal canal, which lowers the risk of spinal cord injury, and avoids the vertebral artery, which typically enters the transverse foramen at C6.

Question 7413

Topic: 6. Spine

A 62-year-old male with a 30-year history of ankylosing spondylitis presents to the emergency department with severe neck pain following a ground-level fall.

Given the rigid nature of his spine, what is the most common and characteristic cervical fracture pattern seen in this patient population?

. Flexion-compression fracture
. Burst fracture of the lower cervical spine
. Transvertebral or transdiscal extension fracture
. Unilateral facet dislocation
. Odontoid type II fracture

Correct Answer & Explanation

. Transvertebral or transdiscal extension fracture

Explanation

Due to extensive ossification and altered biomechanics, the spine in ankylosing spondylitis acts as a long, rigid lever arm. Ground-level falls typically cause highly unstable hyperextension injuries that shear across the disc space or vertebral body.

Question 7414

Topic: 6. Spine

A 34-year-old male with confirmed ankylosing spondylitis has persistent axial pain and morning stiffness despite maximum continuous therapy with two different nonsteroidal anti-inflammatory drugs (NSAIDs) for three months. What is the most appropriate next step in medical management?

. Oral corticosteroids
. Methotrexate
. Tumor necrosis factor (TNF) alpha inhibitors
. Intravenous bisphosphonates
. Rituximab

Correct Answer & Explanation

. Tumor necrosis factor (TNF) alpha inhibitors

Explanation

TNF-alpha inhibitors (e.g., etanercept, infliximab) are the established first-line biologic therapy for axial ankylosing spondylitis in patients who have failed or are intolerant to NSAIDs. Traditional disease-modifying antirheumatic drugs (DMARDs) like methotrexate lack efficacy for isolated axial disease.

Question 7415

Topic: 6. Spine

A 45-year-old male with long-standing ankylosing spondylitis presents with localized, progressive mechanical back pain. Radiographs demonstrate a destructive discovertebral lesion with surrounding reactive sclerosis. Inflammatory markers are mildly elevated.

What is the most likely diagnosis?

. Pyogenic spondylodiscitis
. Tuberculous spondylitis (Pott's disease)
. Andersson lesion
. Romanus lesion
. Multiple myeloma

Correct Answer & Explanation

. Andersson lesion

Explanation

An Andersson lesion represents a localized discovertebral pseudarthrosis in the rigid ankylosed spine, usually secondary to an unrecognized fracture. It presents with mechanical pain and destructive radiographic changes that can mimic infection.

Question 7416

Topic: 6. Spine

A 55-year-old patient with long-standing ankylosing spondylitis is scheduled for orthopedic surgery under general anesthesia. Which of the following represents the most critical anesthetic challenge in this patient?

. High susceptibility to malignant hyperthermia
. Difficult airway management and intubation
. Profound intraoperative bradycardia
. Increased risk of adrenal crisis
. Rapid metabolism of nondepolarizing muscle relaxants

Correct Answer & Explanation

. Difficult airway management and intubation

Explanation

Ankylosing spondylitis results in a rigid, often kyphotic cervical spine and restricted temporomandibular joint mobility. This makes direct laryngoscopy and endotracheal intubation exceptionally difficult, often requiring awake fiberoptic intubation.

Question 7417

Topic: 6. Spine

A 50-year-old male with ankylosing spondylitis presents with a severe chin-on-chest deformity, rendering him unable to look straight ahead. The primary kyphosis is located at the cervicothoracic junction. What is the surgical procedure of choice to correct this deformity?

. Occipitocervical fusion
. Cervicothoracic extension osteotomy (e.g., C7-T1)
. Anterior cervical discectomy and fusion (ACDF)
. Lumbar pedicle subtraction osteotomy (PSO)
. Thoracoscopic anterior release

Correct Answer & Explanation

. Cervicothoracic extension osteotomy (e.g., C7-T1)

Explanation

Fixed cervicothoracic kyphosis (chin-on-chest deformity) in ankylosing spondylitis is best addressed with a posterior opening wedge extension osteotomy, most commonly performed at the C7-T1 level due to the wider spinal canal and avoidance of the vertebral artery.

Question 7418

Topic: 6. Spine

A 45-year-old male with long-standing ankylosing spondylitis presents after a minor fall with severe neck pain. Radiographs reveal a fracture through the C6-C7 disc space extending through the posterior elements. What is the most appropriate management?

. Rigid cervical collar for 6 weeks
. Anterior cervical plating alone
. Cervical laminectomy without fusion
. Long-segment posterior instrumentation and fusion
. Interlaminar clamp placement

Correct Answer & Explanation

. Long-segment posterior instrumentation and fusion

Explanation

Patients with ankylosing spondylitis are at high risk for unstable "chalk-stick" fractures even from minor trauma. These injuries are highly unstable and typically require long-segment posterior instrumentation and fusion, sometimes combined with anterior fixation.

Question 7419

Topic: 6. Spine

A 28-year-old male presents with alternating buttock pain and morning stiffness improving with activity. Radiographs reveal bilateral sacroiliitis.

Which of the following extra-articular manifestations is most commonly associated with this condition?

. Acute anterior uveitis
. Aortic regurgitation
. Apical pulmonary fibrosis
. IgA nephropathy
. Inflammatory bowel disease

Correct Answer & Explanation

. Acute anterior uveitis

Explanation

Acute anterior uveitis is the most common extra-articular manifestation of ankylosing spondylitis, occurring in up to 25-30% of patients. Cardiac and pulmonary complications are less common.

Question 7420

Topic: 6. Spine

A patient with advanced ankylosing spondylitis sustains a minimal trauma fracture of the thoracic spine.

The fracture is noted to be a completely unstable, transdiscal shear injury. Which pathological process makes the spine biomechanically susceptible to this fracture pattern?

. Ossification of the posterior longitudinal ligament (OPLL)
. Loss of bone mineral density combined with complete ankylosis forming a rigid lever arm
. Syringomyelia formation
. Degenerative disc space narrowing
. Primary facet joint hypertrophy

Correct Answer & Explanation

. Loss of bone mineral density combined with complete ankylosis forming a rigid lever arm

Explanation

In ankylosing spondylitis, the spine becomes a continuous, rigid bone due to syndesmophyte formation and facet ankylosis, acting as a long lever arm. This, combined with secondary osteoporosis, makes it highly susceptible to unstable "chalk-stick" shear fractures from minimal trauma.

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