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6. Spine MCQs

Practice Set 63 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 1241

Topic: Cervical Spine

A 6-year-old child presents with severe genu valgum, short stature, and normal intelligence. Radiographs show platyspondyly and odontoid hypoplasia. A deficiency in which of the following enzymes is the most likely cause?

. Galactosamine-6-sulfatase
. Alpha-L-iduronidase
. Iduronate sulfatase
. Arylsulfatase B
. Glucocerebrosidase

Correct Answer & Explanation

. Galactosamine-6-sulfatase

Explanation

Morquio syndrome (MPS IV) presents with normal intelligence, severe skeletal dysplasia, and odontoid hypoplasia. It is caused by a deficiency in galactosamine-6-sulfatase (Type A) or beta-galactosidase (Type B).

Question 1242

Topic: 6. Spine

A 4-year-old boy with rhizomelic short stature has a known mutation in the FGFR3 gene. As this patient reaches adulthood, which of the following spinal abnormalities is most likely to require surgical intervention?

. Cervical kyphosis
. Thoracic scoliosis
. Lumbar spinal stenosis
. Atlantoaxial instability
. Spondylolysis

Correct Answer & Explanation

. Lumbar spinal stenosis

Explanation

Achondroplasia is caused by a gain-of-function mutation in the FGFR3 gene. In adulthood, symptomatic lumbar spinal stenosis is common due to anatomically short pedicles and a progressively decreasing interpedicular distance.

Question 1243

Topic: 6. Spine

Spinal muscular atrophy is best characterized as which of the following:

. An upper motor neuropathy
. A lower motor neuropathy
. A sensory neuropathy
. A peripheral neuropathy
. A generalized myopathy

Correct Answer & Explanation

. A lower motor neuropathy

Explanation

Spinal muscular atrophy is a degeneration of the anterior horn cells of the spinal cord. It results in a nonprogressive lower motor neuron disease with preservation of sensation and intelligence. There is no spasticity or hyperreflexia.

Question 1244

Topic: 6. Spine

Which of the following is the gene that is abnormal in spinal muscular atrophy:

. Survival motor neuron genes 1 and 2
. Gene for dystrophin
. Gene for frataxin
. Gene for peripheral myelin protein
. Gene for emerin

Correct Answer & Explanation

. Survival motor neuron genes 1 and 2

Explanation

Spinal muscular atrophy is a disorder of survival motor neuron genes 1 and 2; its product is not yet known. Dystrophin is abnormal in Duchenne and Becker muscular dystrophy. Frataxin is abnormal in Friedreich ataxia. Peripheral myelin protein is defective in C harcot-Marie-Tooth disease. Emerin is abnormal in Emery-Dreifuss syndrome.

Question 1245

Topic: 6. Spine

Emery-Dreifuss syndrome is manifest by all of the following except:

. Heel cord contractures
. Elbow contractures
. Limited cervical flexion
. Scoliosis
. C ardiomyopathy

Correct Answer & Explanation

. Scoliosis

Explanation

Emery-Dreifuss syndrome is due to an encoding error in emerin, which may be a stabilizer of the nuclear membrane. Emery- Dreifuss syndrome is characterized by a triad of contractures of the heel cord, elbow, and cervical spine. Cardiomyopathy may cause heart block or other arrhytmias. Scoliosis is not commonly found in this condition.

Question 1246

Topic: 6. Spine

A neonate is diagnosed with achondroplasia. The parents ask about potential severe neurological complications. Which of the following is the most life-threatening neurological complication in infants with this condition?

. Syringomyelia
. Thoracolumbar kyphosis
. Foramen magnum stenosis
. Lumbar spinal stenosis
. Tethered cord syndrome

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Foramen magnum stenosis is a critical complication in infants with achondroplasia. It can cause cervicomedullary compression, leading to central apnea and sudden death if not decompressed surgically.

Question 1247

Topic: 6. Spine

A 15-year-old gymnast presents with chronic mechanical low back pain exacerbated by extension. Radiographs are normal, but an MRI demonstrates bone marrow edema in the L5 pars interarticularis without a fracture line. What is the most appropriate initial management?

. Multilevel spinal fusion
. Laminectomy and pars repair
. Corticosteroid injection
. Rest from aggravating activities and antilordotic bracing
. Lumbar epidural steroid injection

Correct Answer & Explanation

. Rest from aggravating activities and antilordotic bracing

Explanation

Bone marrow edema in the pars represents an early stress reaction (pre-spondylolysis). Initial treatment involves conservative management, specifically cessation of sports, rest, and often an antilordotic brace to allow healing.

Question 1248

Topic: 6. Spine

A 6-year-old patient with Morquio syndrome (Mucopolysaccharidosis Type IVA) requires orthopedic clearance before a general anesthetic for dental surgery. Which of the following radiographic studies is most critical to obtain?

. AP pelvis radiograph
. AP and lateral thoracolumbar spine
. Flexion-extension cervical spine radiographs
. Bilateral lower extremity scanogram
. AP and lateral chest radiographs

Correct Answer & Explanation

. Flexion-extension cervical spine radiographs

Explanation

Patients with Morquio syndrome frequently have odontoid hypoplasia and severe atlantoaxial instability. Flexion-extension cervical spine radiographs are critical to evaluate for instability to avoid catastrophic neurologic injury during intubation.

Question 1249

Topic: Thoracolumbar Spine & Deformity

In a 6-year-old boy diagnosed with Duchenne Muscular Dystrophy (DMD), the administration of systemic corticosteroids is aimed primarily at achieving which of the following?

. Reversing the dystrophin gene mutation
. Curing the associated cardiomyopathy
. Preventing the development of scoliosis indefinitely
. Prolonging independent ambulation
. Enhancing fine motor skills in the upper extremities

Correct Answer & Explanation

. Prolonging independent ambulation

Explanation

Systemic corticosteroids are a mainstay of medical therapy for Duchenne Muscular Dystrophy. They have been shown to prolong independent ambulation, preserve pulmonary function, and delay the onset of severe scoliosis.

Question 1250

Topic: 6. Spine

An infant with achondroplasia presents with hypotonia, central apnea, and hyperreflexia. Which of the following is the most likely cause of these symptoms?

. Hydrocephalus
. Cervical kyphosis
. Foramen magnum stenosis
. Thoracolumbar kyphosis
. Spinal muscular atrophy

Correct Answer & Explanation

. Foramen magnum stenosis

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis, which can cause cervicomedullary compression leading to central apnea, hypotonia, and sudden death. Urgent neurosurgical decompression is indicated if the patient is symptomatic.

Question 1251

Topic: 6. Spine

A 4-year-old girl presents with congenital scoliosis secondary to a fully segmented hemivertebra at T8. The curve has progressed by 15 degrees over the past year. What is the most appropriate definitive management?

. Thoracolumbosacral orthosis (TLSO) bracing
. Mehta casting
. Hemivertebra excision and short-segment spinal fusion
. Growing rod construct
. Observation until age 10

Correct Answer & Explanation

. Hemivertebra excision and short-segment spinal fusion

Explanation

Congenital scoliosis caused by a fully segmented hemivertebra carries a high risk of rapid progression and does not respond to bracing. The definitive treatment of choice for a progressing, isolated fully segmented hemivertebra is excision and short-segment fusion.

Question 1252

Topic: 6. Spine

A 65-year-old man with cervical spondylotic myelopathy presents with worsening hand clumsiness and gait imbalance. During examination, flicking the nail of the middle finger produces reflex flexion of the thumb and index finger. This clinical sign indicates pathology involving which of the following?

. Anterior horn cells
. Peripheral nerve
. Upper motor neuron
. Dorsal root ganglion
. Neuromuscular junction

Correct Answer & Explanation

. Upper motor neuron

Explanation

The clinical finding described is Hoffmann's sign, which indicates upper motor neuron dysfunction. In the context of cervical spondylosis, it is a key exam finding for cervical myelopathy caused by spinal cord compression.

Question 1253

Topic: 6. Spine

According to the Denis three-column theory of the spine, a burst fracture of the L1 vertebra involves failure of which spinal columns?

. Anterior column only
. Anterior and middle columns
. Middle column only
. Middle and posterior columns
. Anterior, middle, and posterior columns

Correct Answer & Explanation

. Anterior and middle columns

Explanation

The Denis classification defines a burst fracture as involving failure of both the anterior and middle columns under axial loading. Failure of the middle column distinguishes it from a simple anterior compression fracture.

Question 1254

Topic: 6. Spine

A 65-year-old female presents with worsening hand dexterity, dropping objects, and a broad-based, unsteady gait. Physical examination reveals a positive Hoffmann sign and hyperreflexia in the lower extremities. Which of the following is the most sensitive imaging modality for evaluating the suspected pathology?

. Anteroposterior and lateral radiographs of the cervical spine
. Magnetic Resonance Imaging (MRI) of the cervical spine
. Computed Tomography (CT) myelogram
. Electromyography and nerve conduction studies (EMG/NCS)
. Somatosensory evoked potentials (SSEP)

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI) of the cervical spine

Explanation

The clinical presentation is classic for cervical spondylotic myelopathy. MRI of the cervical spine is the most sensitive and specific modality to evaluate spinal cord compression and intramedullary signal changes.

Question 1255

Topic: 6. Spine

A 60-year-old male reports bilateral posterior leg pain and heaviness that worsens after 10 minutes of walking but is rapidly relieved when he leans forward on a shopping cart. MRI demonstrates severe L4-L5 central canal stenosis. Hypertrophy of which ligament significantly contributes to this central canal narrowing?

. Anterior longitudinal ligament
. Posterior longitudinal ligament
. Ligamentum flavum
. Interspinous ligament
. Supraspinous ligament

Correct Answer & Explanation

. Ligamentum flavum

Explanation

Lumbar spinal stenosis is primarily caused by a combination of disc bulging, facet joint arthropathy, and hypertrophy or buckling of the ligamentum flavum, which directly compresses the dorsal aspect of the thecal sac.

Question 1256

Topic: 6. Spine
A 65-year-old man presents with bilateral hand clumsiness, difficulty buttoning his shirt, and a broad-based, unsteady gait. Examination reveals a positive Hoffman's sign. What is the most likely diagnosis?
. Amyotrophic lateral sclerosis
. Cervical spondylotic myelopathy
. Carpal tunnel syndrome
. Guillain-Barré syndrome
. Lumbar spinal stenosis

Correct Answer & Explanation

. Cervical spondylotic myelopathy

Explanation

Cervical spondylotic myelopathy classically presents with upper motor neuron signs (like Hoffman's sign), hand clumsiness, loss of fine motor skills, and gait instability due to spinal cord compression in the cervical spine.

Question 1257

Topic: 6. Spine

A 45-year-old man presents to the emergency department with acute onset of severe lower back pain, bilateral sciatica, perineal numbness, and urinary retention with overflow incontinence. MRI reveals a massive L4-L5 central disc herniation. What is the most critical next step in management?

. High-dose intravenous dexamethasone
. Epidural steroid injection
. Emergent surgical decompression within 24 to 48 hours
. Strict bed rest for 72 hours
. Lumbar traction

Correct Answer & Explanation

. Emergent surgical decompression within 24 to 48 hours

Explanation

This patient has cauda equina syndrome, an absolute orthopedic and neurosurgical emergency. Emergent surgical decompression (laminectomy and discectomy) should be performed ideally within 24-48 hours to maximize the chance of neurologic and sphincter recovery.

Question 1258

Topic: 6. Spine

A 45-year-old man presents with acute onset of bilateral sciatica, saddle anesthesia, and urinary retention. MRI reveals a massive L4-L5 central disc herniation. Within what time frame is surgical decompression generally recommended to optimize bladder function recovery?

. Within 12 hours
. Within 48 hours
. Within 72 hours
. Within 1 week
. Conservative management is the first line

Correct Answer & Explanation

. Within 48 hours

Explanation

Cauda equina syndrome is an absolute surgical emergency. Decompression within 48 hours has been shown to significantly improve the chances of recovering bladder, bowel, and sexual function compared to later decompression.

Question 1259

Topic: 6. Spine

A 55-year-old woman with longstanding rheumatoid arthritis presents with neck pain and paresthesias in her hands. Flexion-extension radiographs of the cervical spine demonstrate an atlanto-dens interval (ADI) of 8 mm. What does this finding indicate?

. Normal age-related changes
. Atlantoaxial subluxation
. Basilar invagination
. Subaxial cervical stenosis
. Ossification of the posterior longitudinal ligament

Correct Answer & Explanation

. Atlantoaxial subluxation

Explanation

In adults, an atlanto-dens interval (ADI) greater than 3 mm on flexion-extension lateral radiographs is indicative of atlantoaxial instability (subluxation). This is a frequent and potentially devastating complication in patients with advanced rheumatoid arthritis.

Question 1260

Topic: 6. Spine

A 65-year-old man with a 20-year history of severe Rheumatoid Arthritis presents for an elective total hip arthroplasty. Which of the following is the most critical preoperative assessment required before proceeding with general anesthesia and intubation?

. Transthoracic echocardiogram (TTE)
. Flexion-extension cervical spine radiographs
. Pulmonary function tests (PFTs)
. DEXA scan
. Erythrocyte sedimentation rate (ESR) and CRP

Correct Answer & Explanation

. Flexion-extension cervical spine radiographs

Explanation

Patients with long-standing rheumatoid arthritis are at high risk for cervical instability, specifically atlantoaxial subluxation. Flexion-extension cervical spine radiographs are essential preoperatively to evaluate for instability that could cause fatal neurologic injury during intubation.

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