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6. Spine MCQs

Practice Set 373 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 7441

Topic: Thoracolumbar Spine & Deformity

A 6-year-old girl with osteopetrosis presents with facial asymmetry and inability to close her right eye. Which of the following is the primary pathophysiological mechanism for this complication?

. Direct viral infection of the facial nerve
. Autoimmune destruction of the myelin sheath
. Narrowing of the cranial nerve foramina by dense bone
. Ischemic infarction due to vascular dysplasia
. Traction injury from progressive cervical kyphosis

Correct Answer & Explanation

. Narrowing of the cranial nerve foramina by dense bone

Explanation

In osteopetrosis, defective osteoclastic bone resorption leads to progressive skeletal sclerosis and failure of the cranial foramina to expand. This causes progressive cranial nerve entrapment, frequently resulting in facial nerve palsy or blindness.

Question 7442

Topic: 6. Spine

A 75-year-old woman with Paget's disease presents with back pain. An AP radiograph of her lumbar spine shows a single, markedly dense vertebral body with enlargement of the vertebral contours.

This finding is classically described as:

. Rugger jersey spine
. Picture frame vertebra
. Ivory vertebra
. Bamboo spine
. Codfish vertebra

Correct Answer & Explanation

. Ivory vertebra

Explanation

Paget's disease is a classic cause of an 'ivory vertebra,' characterized by a homogeneously dense and enlarged vertebral body. While 'picture frame' vertebra is also seen in Paget's, an ivory vertebra is distinguished by complete diffuse sclerosis.

Question 7443

Topic: 6. Spine

A 65-year-old male with long-standing ankylosing spondylitis presents to the ED after a minor fall. He complains of severe neck pain but has no neurological deficits. Radiographs demonstrate a fracture through the C6-C7 intervertebral disc space extending into the posterior elements.

What is the most appropriate management?

. Hard cervical collar for 6 weeks
. Halo vest immobilization
. Anterior cervical plating only
. Posterior or combined anterior-posterior instrumental fusion
. Soft collar and early mobilization

Correct Answer & Explanation

. Posterior or combined anterior-posterior instrumental fusion

Explanation

Cervical spine fractures in AS are highly unstable, acting as long lever arms, and carry a high risk of neurologic deterioration. Rigid internal fixation, typically posterior or combined anteroposterior, is required due to high failure rates with non-operative management.

Question 7444

Topic: 6. Spine

A 50-year-old patient with known ankylosing spondylitis presents with localized, worsening back pain. Radiographs reveal a destructive disco-vertebral lesion with reactive sclerosis.

What is the primary etiology of this specific lesion?

. Staphylococcus aureus infection
. Mycobacterium tuberculosis infection
. Metastatic prostate carcinoma
. Pseudarthrosis following an occult fracture
. Primary bone lymphoma

Correct Answer & Explanation

. Pseudarthrosis following an occult fracture

Explanation

This describes an Andersson lesion, a non-infectious, destructive disco-vertebral lesion seen in AS. It represents a pseudarthrosis resulting from continued motion at a single unfused segment or an occult fracture in a rigid spine.

Question 7445

Topic: 6. Spine

A 60-year-old male with a 20-year history of ankylosing spondylitis presents after a ground-level fall. He has severe neck pain. Radiographs reveal a displaced C6-C7 discovertebral fracture.

What is the most appropriate definitive management?

. Rigid cervical collar for 12 weeks
. Halo vest immobilization
. Anterior cervical discectomy and fusion (ACDF) only
. Posterior long-segment instrumentation and fusion
. Observation with pain control

Correct Answer & Explanation

. Posterior long-segment instrumentation and fusion

Explanation

Fractures in the ankylosed spine act like long bone fractures and are highly unstable, often involving all three columns. They require rigid, long-segment posterior instrumentation and fusion to prevent catastrophic neurologic decline or nonunion.

Question 7446

Topic: 6. Spine

A 24-year-old male with chronic back pain and stiffness is suspected of having Ankylosing Spondylitis. During the physical examination, the physician makes a mark at the level of the posterior superior iliac spines (dimples of Venus) and another mark 10 cm above it, then asks the patient to flex forward. This test is known as the:

. Patrick's (FABER) test
. Thomas test
. Gaenslen's test
. Schober test
. Lasegue's test

Correct Answer & Explanation

. Schober test

Explanation

The Schober test assesses the restriction of lumbar spine flexion, a hallmark clinical sign of Ankylosing Spondylitis. Normal flexion should increase the distance between the two marks by at least 5 cm.

Question 7447

Topic: 6. Spine

A 45-year-old male with long-standing ankylosing spondylitis presents to the emergency department after a minor fall. He complains of severe neck pain. Radiographs show a fracture extending through the C5-C6 disc space and involving the posterior elements.

What is the most appropriate definitive management?

. Rigid cervical collar immobilization for 12 weeks
. Halo vest application
. Long-segment posterior cervical instrumentation and fusion
. Short-segment anterior cervical discectomy and fusion
. Observation with soft collar

Correct Answer & Explanation

. Long-segment posterior cervical instrumentation and fusion

Explanation

Spinal fractures in ankylosing spondylitis are highly unstable, often involving all three columns, and carry a high risk of neurologic compromise. Due to altered biomechanics, standard treatment requires long-segment posterior instrumentation and fusion to ensure adequate stabilization.

Question 7448

Topic: 6. Spine

A 35-year-old male with ankylosing spondylitis has a severe chin-on-chest deformity, rendering him unable to look straight ahead.

If surgical correction is planned, at which spinal level is an extension osteotomy most safely and commonly performed to correct the cervicothoracic kyphosis?

. C1-C2
. C7-T1
. T4-T5
. L1-L2
. L4-L5

Correct Answer & Explanation

. C7-T1

Explanation

The C7-T1 junction is the preferred site for a cervicothoracic extension osteotomy in ankylosing spondylitis. This level is chosen because the spinal canal is relatively wide here, and the vertebral artery typically enters the transverse foramen at C6, leaving C7-T1 safer for bony resection.

Question 7449

Topic: 6. Spine

A 50-year-old male with long-standing ankylosing spondylitis presents with localized, non-radiating thoracolumbar back pain. Radiographs reveal a destructive, irregular discovertebral lesion at T12-L1 with reactive sclerosis, mimicking discitis. His CRP is only mildly elevated. What is this lesion called?

. Tuberculous spondylodiscitis
. Pyogenic discitis
. Andersson lesion
. Metastatic carcinoma
. Romanus lesion

Correct Answer & Explanation

. Andersson lesion

Explanation

An Andersson lesion is a non-infectious inflammatory discovertebral lesion or pseudoarthrosis seen in ankylosing spondylitis. It occurs due to localized stress fractures through an ankylosed spine segment and can closely mimic infection on imaging.

Question 7450

Topic: 6. Spine

A 28-year-old male with HLA-B27 positive ankylosing spondylitis presents for a routine follow-up. He complains of chronic, inflammatory lower back pain. Which of the following is the most common extra-articular manifestation associated with his underlying condition?

. Plaque psoriasis
. Inflammatory bowel disease
. Acute anterior uveitis
. Aortic regurgitation
. Apical pulmonary fibrosis

Correct Answer & Explanation

. Acute anterior uveitis

Explanation

Acute anterior uveitis (iritis) is the most common extra-articular manifestation of ankylosing spondylitis, occurring in approximately 25-30% of patients. It typically presents as an acutely painful, red eye with photophobia.

Question 7451

Topic: 6. Spine

A 32-year-old male with active ankylosing spondylitis has persistent axial disease (sacroiliitis and spondylitis) despite maximally tolerated doses of two different NSAIDs. He has no peripheral joint involvement. What is the most appropriate next step in his medical management?

. Initiate oral methotrexate
. Initiate oral sulfasalazine
. Initiate a Tumor Necrosis Factor (TNF) inhibitor
. Initiate high-dose oral corticosteroids
. Perform serial intra-articular steroid injections

Correct Answer & Explanation

. Initiate a Tumor Necrosis Factor (TNF) inhibitor

Explanation

For patients with active axial ankylosing spondylitis who fail NSAID therapy, TNF inhibitors (e.g., infliximab, adalimumab) or IL-17 inhibitors are the recommended next step. Conventional synthetic DMARDs like methotrexate and sulfasalazine are ineffective for pure axial disease.

Question 7452

Topic: 6. Spine

A 65-year-old man with advanced Ankylosing Spondylitis presents after a minor fall with severe neck pain. Radiographs are inconclusive. What is the most appropriate next step in management?

. Discharge with NSAIDs and a soft collar
. Flexion-extension cervical radiographs
. CT or MRI of the entire cervical and thoracic spine
. Bone scintigraphy
. Reassurance and physical therapy

Correct Answer & Explanation

. CT or MRI of the entire cervical and thoracic spine

Explanation

Patients with Ankylosing Spondylitis have a rigid, brittle spine highly susceptible to unstable fractures even from minor trauma. If standard radiographs are negative but the patient has pain, cross-sectional imaging (CT or MRI) is mandatory to rule out occult fractures.

Question 7453

Topic: 6. Spine

A 68-year-old man with long-standing Ankylosing Spondylitis presents with a severe chin-on-chest deformity. Which cervical level is most commonly chosen for a closing wedge extension osteotomy to correct this deformity?

. C1-C2
. C3-C4
. C5-C6
. C7-T1
. T4-T5

Correct Answer & Explanation

. C7-T1

Explanation

The cervicothoracic junction (C7-T1) is the preferred level for extension osteotomies in ankylosing spondylitis. This level has a wider spinal canal minimizing spinal cord injury risk, and the mobility of the spinal cord is relatively greater here than in the mid-cervical spine.

Question 7454

Topic: 6. Spine

A 55-year-old male with long-standing Ankylosing Spondylitis (AS) presents to the emergency department with severe neck pain following a minor fall from standing height. A CT scan of the cervical spine demonstrates a through-and-through chalk-stick fracture at the C5-C6 level. What is the most appropriate surgical management for this patient?

. Hard cervical collar immobilization
. Anterior cervical plating only
. Long-segment posterior instrumentation
. Halo vest immobilization
. Corticosteroid injection

Correct Answer & Explanation

. Long-segment posterior instrumentation

Explanation

Spinal fractures in ankylosing spondylitis are highly unstable (often three-column injuries) and are managed similarly to long-bone fractures. Long-segment posterior instrumentation (often 3 levels above and below) is required to provide adequate biomechanical stability and prevent catastrophic neurologic injury.

Question 7455

Topic: 6. Spine

A 45-year-old male with advanced Ankylosing Spondylitis presents with fixed global positive sagittal imbalance. Surgical correction using a pedicle subtraction osteotomy (PSO) is planned. To maximize lordosis restoration and minimize the risk of spinal cord injury, what is the ideal spinal level for the PSO?

. T10
. T12
. L3
. L5
. S1

Correct Answer & Explanation

. L3

Explanation

The L3 level is considered the ideal site for a pedicle subtraction osteotomy (PSO) in patients with AS. It allows for significant restoration of lumbar lordosis while remaining well below the level of the conus medullaris, reducing the risk of permanent neurologic injury.

Question 7456

Topic: 6. Spine

A 72-year-old male with a known history of ankylosing spondylitis presents with severe back pain after minor trauma. Imaging reveals a transvertebral fracture.

Which of the following is the most appropriate definitive management for this patient?

. Cervicothoracic orthosis (CTO) for 12 weeks
. Short-segment posterior spinal fusion
. Long-segment posterior spinal fusion
. Anterior cervical corpectomy and fusion alone
. Physical therapy and observation

Correct Answer & Explanation

. Long-segment posterior spinal fusion

Explanation

Fractures in ankylosing spondylitis are highly unstable due to the altered biomechanics of the fused "bamboo" spine. They typically require long-segment posterior spinal instrumentation spanning at least three levels above and below the fracture to prevent secondary neurological injury.

Question 7457

Topic: 6. Spine

A 50-year-old male with long-standing ankylosing spondylitis presents with localized, worsening back pain without a history of trauma. Radiographs show a destructive discovertebral lesion with reactive sclerosis.

What is the most likely diagnosis?

. Pyogenic spondylodiscitis
. Tuberculous spondylitis
. Andersson lesion
. Metastatic prostate cancer
. Multiple myeloma

Correct Answer & Explanation

. Andersson lesion

Explanation

Andersson lesions represent non-infectious, destructive discovertebral lesions seen in advanced ankylosing spondylitis. They often result from pseudoarthrosis at the site of unhealed stress fractures in the rigid, fused spine.

Question 7458

Topic: 6. Spine

A 32-year-old male with human leukocyte antigen (HLA)-B27 positive ankylosing spondylitis presents with acute unilateral eye pain, photophobia, and blurred vision. What is the most likely extra-articular manifestation he is experiencing?

. Scleritis
. Keratoconjunctivitis sicca
. Acute anterior uveitis
. Optic neuritis
. Glaucoma

Correct Answer & Explanation

. Acute anterior uveitis

Explanation

Acute anterior uveitis (iritis) is the most common extra-articular manifestation of ankylosing spondylitis, occurring in 25-30% of patients. It requires prompt ophthalmological evaluation to prevent synechiae and vision loss.

Question 7459

Topic: 6. Spine

A 45-year-old male with severe ankylosing spondylitis presents with a fixed chin-on-chest deformity causing difficulty swallowing and impaired horizontal gaze. He is scheduled for an extension osteotomy. Which level is most appropriate for the osteotomy to correct the cervical deformity?

. C1-C2
. C3-C4
. C5-C6
. C7-T1
. T4-T5

Correct Answer & Explanation

. C7-T1

Explanation

Cervicothoracic kyphosis in AS is typically corrected with an extension osteotomy at the C7-T1 level. This level has a wide spinal canal and is below the vertebral artery's usual entry point at C6, minimizing neurological and vascular risks.

Question 7460

Topic: 6. Spine

A 60-year-old male with long-standing ankylosing spondylitis presents with increasing difficulty looking forward due to a severe rigid cervicothoracic kyphosis. A cervical extension osteotomy is planned to correct his chin-on-chest deformity. At which anatomic level is this osteotomy most safely and classically performed?

. C1-C2
. C4-C5
. C7-T1
. T3-T4
. T10-T11

Correct Answer & Explanation

. C7-T1

Explanation

Cervical extension osteotomies in ankylosing spondylitis are classically performed at the C7-T1 junction. The spinal canal is relatively wide at this level, and the flexibility of the adjacent shoulders and rib cage allows for safer correction with lower risk to the vertebral arteries.

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