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6. Spine MCQs

Practice Set 296 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 5901

Topic: 6. Spine

A 48-year-old female with a 15-year history of rheumatoid arthritis presents with progressive neck pain and intermittent "electric shock" sensations radiating down her arms when she flexes her neck. Flexion-extension cervical spine radiographs reveal an Anterior Atlanto-Dental Interval (AADI) of 11 mm and a Posterior Atlanto-Dental Interval (PADI) of 12 mm. What is the most appropriate management?

. Application of a rigid cervical orthosis
. Posterior C1-C2 fusion
. Anterior odontoid screw fixation
. Subaxial cervical decompression
. Occipitocervical fusion

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

The patient exhibits Lhermitte's sign and significant atlantoaxial subluxation. Indications for surgery in RA cervical spine include an AADI > 9-10 mm, PADI < 14 mm, or neurological deficit; a posterior C1-C2 fusion is indicated here without superior migration of the odontoid.

Question 5902

Topic: 6. Spine

A 50-year-old male presents with severe, progressive back stiffness and large joint pain. Physical examination reveals dark, bluish-black pigmentation of the sclerae and ear cartilage. Radiographs of the spine exhibit profound, widespread calcification of the intervertebral discs. This specific arthropathy is secondary to a deficiency in which of the following enzymes?

. Homogentisate 1,2-dioxygenase
. Phenylalanine hydroxylase
. Lysyl hydroxylase
. Tyrosinase
. Alpha-L-iduronidase

Correct Answer & Explanation

. Homogentisate 1,2-dioxygenase

Explanation

The patient presents with Ochronosis (Alkaptonuria), a rare autosomal recessive metabolic disorder. It is caused by a deficiency of homogentisate 1,2-dioxygenase, leading to the accumulation of homogentisic acid in connective tissues, causing cartilage pigmentation and rapid degeneration.

Question 5903

Topic: 6. Spine

A 14-year-old boy presents with a painful scoliosis that is worse at night.

Imaging reveals an osteoid osteoma in the posterior elements of the thoracic spine. Which of the following is the most classic presentation of spinal deformity in this setting?

. A scoliotic curve with the lesion located on the concavity of the curve
. A scoliotic curve with the lesion located on the convexity of the curve
. A hyperkyphotic deformity with the lesion at the apex
. A hyperlordotic deformity with bilateral spondylolysis
. A fixed structural curve that does not resolve after lesion resection

Correct Answer & Explanation

. A scoliotic curve with the lesion located on the concavity of the curve

Explanation

Osteoid osteomas in the spine frequently cause a painful scoliosis. The intense inflammatory response and localized muscle spasm characteristically cause the spine to curve away from the lesion, placing the tumor on the concavity of the curve.

Question 5904

Topic: Cervical Spine

A 5-year-old child with normal intelligence presents with short-trunk dwarfism, corneal clouding, and knock-knees. Radiographs demonstrate severe platyspondyly with anterior beaking of the vertebral bodies and odontoid hypoplasia. Which of the following substances is excessively accumulating in this patient's tissues?

. Heparan sulfate
. Dermatan sulfate
. Keratan sulfate
. Homogentisic acid
. Glucocerebroside

Correct Answer & Explanation

. Keratan sulfate

Explanation

Morquio Syndrome (Mucopolysaccharidosis Type IV) is an autosomal recessive lysosomal storage disease resulting from a defect in galactosamine-6-sulfatase (Type A) or beta-galactosidase (Type B). This causes the specific accumulation of keratan sulfate. Odontoid hypoplasia makes them highly susceptible to atlantoaxial instability.

Question 5905

Topic: 6. Spine

An 8-year-old boy with NF-1 is referred to orthopedics. Which of the following spinal deformities is most characteristic of this condition and typically requires early, aggressive surgical intervention?

. Right thoracic adolescent idiopathic scoliosis
. Short-segment, sharply angulated dystrophic kyphoscoliosis
. Congenital failure of segmentation (block vertebrae)
. Spondylolisthesis at L5-S1
. Cervical spine hyperlordosis

Correct Answer & Explanation

. Short-segment, sharply angulated dystrophic kyphoscoliosis

Explanation

Dystrophic kyphoscoliosis in NF-1 is characterized by a short, sharply angulated curve with severe vertebral wedging, spindling of the transverse processes, and dural ectasia. It progresses rapidly and usually requires combined anterior and posterior spinal fusion.

Question 5906

Topic: 6. Spine

A 9-year-old child with an extremely restrictive diet presents with gingival bleeding, petechiae, and joint pain. Radiographs reveal a prominent white line of Frankel at the metaphysis. This condition is caused by a nutritional deficiency that directly impairs which step of collagen synthesis?

. Cleavage of procollagen C- and N-terminals
. Hydroxylation of proline and lysine residues
. Glycosylation of hydroxylysine residues
. Formation of the triple helix
. Cross-linking by lysyl oxidase

Correct Answer & Explanation

. Hydroxylation of proline and lysine residues

Explanation

The child has scurvy (Vitamin C deficiency). Vitamin C is a critical cofactor for prolyl hydroxylase and lysyl hydroxylase, enzymes responsible for the intracellular hydroxylation of proline and lysine residues on procollagen alpha chains. Without this, hydrogen bonding is impaired, and stable triple helices cannot form, leading to fragile connective tissues.

Question 5907

Topic: 6. Spine

A 4-year-old child presents with refusal to bear weight and swollen, bleeding gums. Radiographs of the lower extremities reveal a transverse line of increased density at the metaphysis and a ring of increased density around the epiphyses. A defect in which of the following cellular processes is most likely responsible for these findings?

. Hydroxylation of proline and lysine residues
. Cleavage of procollagen C- and N-terminals
. Cross-linking of tropocollagen molecules
. Formation of the triple helix
. Transcription of type I collagen mRNA

Correct Answer & Explanation

. Hydroxylation of proline and lysine residues

Explanation

The clinical and radiographic findings (Frankel's line, Wimberger's ring sign) are classic for scurvy (Vitamin C deficiency). Vitamin C is an essential cofactor for prolyl and lysyl hydroxylases, which are required for the hydroxylation of proline and lysine residues during collagen synthesis.

Question 5908

Topic: 6. Spine

A pediatric patient presents with gingival bleeding, petechiae, and metaphyseal radiolucent bands on radiographs (Frankel's line). The underlying nutritional deficiency primarily impairs which of the following steps in collagen synthesis?

. Cleavage of procollagen C- and N-terminals
. Intracellular hydroxylation of proline and lysine residues
. Extracellular cross-linking by lysyl oxidase
. Triple helix formation via disulfide bonds
. Transcription of COL1A1 genes

Correct Answer & Explanation

. Intracellular hydroxylation of proline and lysine residues

Explanation

The patient has scurvy due to Vitamin C deficiency. Vitamin C acts as a necessary cofactor for prolyl hydroxylase and lysyl hydroxylase, which are required for the intracellular hydroxylation of proline and lysine during collagen synthesis.

Question 5909

Topic: 6. Spine

A 45-year-old male presents to the emergency department with acute low back pain and bilateral sciatica following heavy lifting. Which of the following is considered the most consistent and sensitive early clinical indicator of cauda equina syndrome?

. Saddle anesthesia
. Urinary retention with overflow incontinence
. Decreased anal sphincter tone
. Bilateral absence of Achilles reflexes
. Fecal incontinence

Correct Answer & Explanation

. Urinary retention with overflow incontinence

Explanation

Urinary retention is the most sensitive early sign of cauda equina syndrome (CES), often manifesting with a post-void residual > 100-200 mL. While saddle anesthesia, decreased rectal tone, and fecal incontinence are classic signs, urinary retention generally precedes them, and its absence makes CES highly unlikely.

Question 5910

Topic: 6. Spine

A 68-year-old male complains of worsening fine motor clumsiness, difficulty buttoning his shirt, and gait instability. Exam reveals a positive Hoffmann sign and hyperreflexia. MRI of the cervical spine shows severe stenosis at C5-C6. Which of the following MRI findings is most predictive of a poor neurological recovery following surgical decompression?

. Loss of cervical lordosis on sagittal sequences
. T2 hyperintensity within the spinal cord that resolves on T1
. Decreased disc height at the affected level
. T1 hypointensity within the spinal cord
. Ossification of the posterior longitudinal ligament (OPLL)

Correct Answer & Explanation

. T1 hypointensity within the spinal cord

Explanation

In Cervical Spondylotic Myelopathy (CSM), signal changes within the spinal cord dictate prognosis. T2 hyperintensity represents edema or gliosis and can be reversible. However, T1 hypointensity ('black holes') in the spinal cord indicates myelomalacia (cystic necrosis/permanent cord damage) and is a strong independent predictor of poor clinical outcome and lack of recovery post-decompression.

Question 5911

Topic: 6. Spine

A 45-year-old male suffers a burst fracture of T12 with complete spinal cord injury. On arrival at the emergency department, he is warm, flushed, and has a blood pressure of 80/40 mmHg with a heart rate of 52 beats per minute. Which of the following best describes the pathophysiology of his hemodynamic state?

. Loss of sympathetic tone leading to unopposed parasympathetic response
. Acute blood loss from the burst fracture leading to hypovolemia
. Systemic inflammatory response to spinal trauma
. Transient loss of all spinal reflexes below the level of injury
. Cardiac contusion from the traumatic impact

Correct Answer & Explanation

. Loss of sympathetic tone leading to unopposed parasympathetic response

Explanation

The patient is experiencing neurogenic shock, characterized by hypotension and bradycardia due to the loss of sympathetic vasomotor tone and unopposed vagal (parasympathetic) activity. This must be distinguished from spinal shock, which refers to the transient loss of spinal reflexes.

Question 5912

Topic: 6. Spine

A 25-year-old male is brought to the ED after a diving accident. He is awake, alert, and cooperative. Examination reveals bilateral upper and lower extremity weakness consistent with an incomplete spinal cord injury. Imaging

demonstrates a bilateral C5-C6 facet dislocation. According to major guidelines, what is the most appropriate next step in management?

. Immediate open posterior reduction and fusion
. Immediate open anterior reduction and fusion
. Closed reduction with cranial traction in the ED with serial neurologic exams
. Immediate MRI prior to any reduction attempts
. Application of a halo vest and definitive surgery at 1 week

Correct Answer & Explanation

. Closed reduction with cranial traction in the ED with serial neurologic exams

Explanation

In an awake, cooperative, and testable patient with a cervical facet dislocation, urgent closed reduction using cranial traction (e.g., Gardner-Wells tongs) with serial neurological examinations is indicated. An MRI prior to reduction is generally reserved for patients who are obtunded, uncooperative, or who fail closed reduction, as delaying reduction to obtain an MRI can prolong spinal cord ischemia.

Question 5913

Topic: 6. Spine

A 65-year-old man presents with deteriorating handwriting, dropping objects, and frequent tripping over the past year. Examination reveals a positive Hoffman's sign and hyperreflexia. A cervical MRI

confirms severe stenosis at C4-C6. He is still able to ambulate, but requires the daily use of a cane. What is his Nurick classification grade?

. Grade 1
. Grade 2
. Grade 3
. Grade 4
. Grade 5

Correct Answer & Explanation

. Grade 4

Explanation

The Nurick scale assesses cervical myelopathy based on gait impairment. Grade 0: Root signs only. Grade 1: Signs of cord involvement, normal gait. Grade 2: Mild gait abnormality, but employed. Grade 3: Gait abnormality prevents employment, can walk unassisted. Grade 4: Ambulates only with assistance (cane, walker). Grade 5: Chairbound or bedridden. Because he requires a cane, he is Grade 4.

Question 5914

Topic: 6. Spine

A 72-year-old male is evaluated for progressive clumsiness. Examination reveals hyperreflexia in the lower extremities and a positive Hoffmann's sign. Radiographs show significant cervical spondylosis.

What is typically the earliest presenting clinical symptom in cervical spondylotic myelopathy?

. Bowel and bladder incontinence
. Intrinsic hand muscle wasting
. Gait changes and balance dysfunction
. Severe neck pain
. Unilateral radicular arm pain

Correct Answer & Explanation

. Gait changes and balance dysfunction

Explanation

Subtle gait disturbance and loss of balance are typically the earliest presenting symptoms of cervical spondylotic myelopathy (CSM). Hand clumsiness and fine motor difficulty usually follow closely.

Question 5915

Topic: 6. Spine

A 45-year-old male presents with acute onset saddle anesthesia, bilateral radicular leg pain, and urinary retention. Which of the following MRI findings is the most absolute indication for emergent surgical decompression?

. L4-L5 disc herniation with severe bilateral foraminal stenosis
. L5-S1 central disc herniation with mass effect on the cauda equina
. L3-L4 central disc herniation without thecal sac compression
. Grade I L4-L5 degenerative spondylolisthesis
. L5 pars interarticularis defect

Correct Answer & Explanation

. L5-S1 central disc herniation with mass effect on the cauda equina

Explanation

Urinary retention with saddle anesthesia indicates Cauda Equina Syndrome. A central disc herniation compressing the cauda equina requires emergent surgical decompression to optimize functional urologic and neurologic recovery.

Question 5916

Topic: 6. Spine

A patient sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). A Levine-Edwards Type II fracture is characterized by disruption of the C2-C3 disc and posterior longitudinal ligament, causing significant angulation and translation. What is the primary mechanism of injury?

. Hyperextension and axial loading
. Hyperflexion and compression
. Hyperextension and rebound flexion
. Axial distraction
. Lateral bending

Correct Answer & Explanation

. Hyperextension and rebound flexion

Explanation

A Levine-Edwards Type II Hangman's fracture is classically caused by a hyperextension force followed by rebound flexion. It results in significant anterior translation and angulation of C2 on C3.

Question 5917

Topic: 6. Spine

A 65-year-old male presents with chronic low back pain radiating into both calves, exacerbated by standing and walking, and relieved by sitting or leaning forward. Physical examination reveals intact motor strength and sensation, with diminished ankle reflexes bilaterally. What is the most likely diagnosis?

. Lumbar disc herniation
. Spondylolisthesis
. Lumbar spinal stenosis
. Piriformis syndrome
. Facet arthropathy

Correct Answer & Explanation

. Lumbar spinal stenosis

Explanation

This classic presentation of neurogenic claudication (exacerbated by standing/walking, relieved by sitting or leaning forward, often termed the 'shopping cart sign') is highly suggestive of lumbar spinal stenosis. Lumbar disc herniation typically presents with more acute, often unilateral radiculopathy. Spondylolisthesis can contribute to stenosis but the specific activity-dependent pain pattern points directly to stenosis. Piriformis syndrome usually causes buttock pain with radiation, often worsened by hip internal rotation. Facet arthropathy primarily causes axial back pain, potentially with referred pain, but less commonly classic neurogenic claudication.

Question 5918

Topic: 6. Spine

A 5-year-old child presents with a progressive idiopathic scoliosis measuring 45 degrees, with a high risk of progression. What is the most appropriate management?

. Observation every 6-12 months
. Initiation of bracing
. Surgical spinal fusion
. Physical therapy and exercises
. Chiropractic manipulation

Correct Answer & Explanation

. Surgical spinal fusion

Explanation

For progressive idiopathic scoliosis in a 5-year-old with a curve measuring 45 degrees, surgical spinal fusion is generally indicated. Bracing is typically used for curves between 25-45 degrees in skeletally immature patients to prevent progression, but it is less effective for very young children with large curves, or those with significant growth remaining where fusion may be necessary to control severe deformity. Observation is for small, non-progressive curves. Physical therapy and chiropractic manipulation have not been shown to halt curve progression in idiopathic scoliosis. Early fusion in very young children typically involves growth-friendly techniques to allow for continued spinal and thoracic development.

Question 5919

Topic: 6. Spine

A 60-year-old male with a history of lumbar stenosis presents with acute onset bilateral leg weakness, saddle anesthesia, and urinary retention. Physical examination reveals diminished perianal sensation and loss of anal tone. What is the MOST critical immediate diagnostic and management step?

. Prescribe oral corticosteroids and observe
. Order an EMG/NCS
. STAT MRI of the lumbar spine and surgical decompression
. Physical therapy and pain management
. Referral to a urologist for catheterization

Correct Answer & Explanation

. STAT MRI of the lumbar spine and surgical decompression

Explanation

This patient presents with classic signs of Cauda Equina Syndrome (CES), which is a surgical emergency. The critical immediate steps are a STAT MRI of the lumbar spine to confirm the diagnosis and identify the compressive lesion, followed by urgent surgical decompression to prevent permanent neurological deficits. Delay in decompression can lead to irreversible bladder, bowel, and sexual dysfunction. Oral corticosteroids, EMG/NCS, PT, and urology referral are not the primary emergent management.

Question 5920

Topic: 6. Spine

A 40-year-old immigrant presents with chronic back pain, low-grade fever, and significant weight loss over several months. Radiographs show vertebral body destruction and paraspinal soft tissue swelling, most prominent at T10-T11. What is the MOST likely diagnosis, and what is the primary diagnostic test?

. Metastatic spine tumor; whole-body PET scan
. Pyogenic spondylodiscitis; urgent MRI and culture of aspirate
. Ankylosing spondylitis; HLA-B27 testing
. Spinal tuberculosis (Pott's disease); MRI and biopsy for histopathology and acid-fast bacilli culture
. Osteoporotic vertebral fracture; DEXA scan

Correct Answer & Explanation

. Spinal tuberculosis (Pott's disease); MRI and biopsy for histopathology and acid-fast bacilli culture

Explanation

The constellation of chronic back pain, systemic symptoms (fever, weight loss), and radiographic findings of vertebral destruction (especially in a population at risk for TB) strongly points towards Spinal Tuberculosis (Pott's disease). The primary diagnostic test is an MRI to delineate the extent of disease and a biopsy of the affected area (usually percutaneous or open) for histopathological examination and culture for acid-fast bacilli to confirm the diagnosis and guide antitubercular treatment. While pyogenic spondylodiscitis has similar imaging, the chronicity and systemic symptoms favor TB. Other options are less likely given the clinical scenario.

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