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6. Spine MCQs

Practice Set 80 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 1581

Topic: 6. Spine

In the context of congenital scoliosis, various vertebral anomalies can occur, leading to different rates of curve progression. Understanding these differences is crucial for prognosis and management.

What is the correct order of congenital vertebral anomaly types, from most likely to result in progressive scoliosis to least likely to progress?

. Hemivertebra, unilateral bar, wedge vertebra, unilateral bar with contralateral hemivertebra, block vertebra
. Unilateral bar, wedge vertebra, unilateral bar with contralateral hemivertebra, block vertebra, hemivertebra
. Wedge vertebra, unilateral bar with contralateral hemivertebra, block vertebra, hemivertebra, unilateral bar
. Block vertebra, wedge vertebra, hemivertebra, unilateral bar, unilateral bar with contralateral hemivertebra
. Unilateral bar with contralateral hemivertebra, unilateral bar, hemivertebra, wedge vertebra, block vertebra

Correct Answer & Explanation

. Unilateral bar with contralateral hemivertebra, unilateral bar, hemivertebra, wedge vertebra, block vertebra

Explanation

Correct Answer: EThe correct answer is Unilateral bar with contralateral hemivertebra, unilateral bar, hemivertebra, wedge vertebra, block vertebra. This order reflects the increasing severity and likelihood of curve progression in congenital scoliosis due to the imbalance in growth potential.Unilateral bar with contralateral hemivertebra:This is the most severe anomaly, as the unilateral bar acts as a tether on one side, preventing growth, while the contralateral hemivertebra provides an extra growth center on the opposite side. This combination creates a significant growth imbalance, leading to rapid and severe progression.Unilateral bar:A unilateral bar tethers growth on one side of the spine, leading to progressive curvature as the contralateral side continues to grow normally.Hemivertebra:A hemivertebra is a wedge-shaped vertebra that provides an extra growth center on one side, causing a curve. While it can lead to significant progression, it is generally less aggressive than a unilateral bar or a unilateral bar with a contralateral hemivertebra. The case mentions an average 2-5 degree progression per year for a hemivertebra.Wedge vertebra:A wedge vertebra is a partially formed vertebra that is narrower on one side, contributing to a curve but typically with less severe progression than a hemivertebra.Block vertebra:Block vertebrae occur when two or more vertebrae are fused together. While they represent a congenital anomaly, they typically do not cause significant scoliosis because there is no differential growth potential to drive a progressive curve.

Question 1582

Topic: 6. Spine
Following the primary survey, a detailed physical examination of the 15-year-old male reveals sensation is not intact distal to the umbilicus, no sensation around the rectum, and no voluntary rectal tone. He has 5/5 strength in bilateral upper extremities and 0/5 strength in all key muscles of the bilateral lower extremities. When his glans penis is squeezed during a simultaneous digital rectal examination, the muscles surrounding his rectum contract around your finger. What is the neurophysiological pathway by which the bulbocavernosus reflex (BCR) works?
. Genitofemoral nerve β†’ afferent pudendal nerve fibers β†’ sacral plexus β†’ efferent pudendal nerve fibers β†’ perineal muscle
. Genitofemoral nerve β†’ afferent obturator nerve fibers β†’ sacral plexus β†’ efferent obturator nerve fibers β†’ perineal muscle
. Dorsal penile nerve β†’ afferent ilioinguinal nerve fibers β†’ sacral plexus β†’ efferent ilioinguinal nerve fibers β†’ perineal muscle
. Dorsal penile nerve β†’ efferent pudendal nerve fibers β†’ sacral plexus β†’ afferent pudendal nerve fibers β†’ perineal muscle
. Dorsal penile nerve β†’ afferent pudendal nerve fibers β†’ sacral plexus β†’ efferent pudendal nerve fibers β†’ perineal muscle

Correct Answer & Explanation

. Dorsal penile nerve β†’ afferent pudendal nerve fibers β†’ sacral plexus β†’ efferent pudendal nerve fibers β†’ perineal muscle

Explanation

The bulbocavernosus reflex (BCR) is a polysynaptic reflex that involves the S2-S4 sacral segments of the spinal cord. The afferent limb of the reflex is carried by the dorsal penile nerve (a branch of the pudendal nerve) to the sacral plexus. The efferent limb, which causes contraction of the bulbocavernosus and external anal sphincter muscles, is carried by the efferent fibers of the pudendal nerve from the sacral plexus to the perineal muscles.

Question 1583

Topic: 6. Spine
Plain radiographs of the 15-year-old male's spine are obtained following his ATV accident. Despite his complete motor and sensory loss below the umbilicus, these radiographs show no evidence of any fractures or displacements. Given the clinical presentation and the radiographic findings, what is the next step in management to definitively diagnose the patient's condition?
. Obtain a CT scan of the thoracic and lumbar spine
. Obtain an MRI without contrast of the thoracic and lumbar spine
. Obtain bending radiographs to observe for instability of the thoracolumbar spine
. Obtain electromyogram and nerve conduction studies of the patient’s bilateral lower extremities
. Administer high-dose corticosteroids immediately

Correct Answer & Explanation

. Obtain an MRI without contrast of the thoracic and lumbar spine

Explanation

The correct answer is to obtain an MRI without contrast of the thoracic and lumbar spine. The patient's clinical picture strongly points toward a spinal cord injury (complete motor and sensory loss), yet the plain radiographs show no evidence of fractures or displacements. This scenario is characteristic of Spinal Cord Injury Without Radiographic Abnormality (SCIWORA). To definitively diagnose SCIWORA and evaluate the spinal cord itself, as well as its surrounding ligaments, an MRI is the gold standard. MRI provides detailed information about soft tissues, including the spinal cord, intervertebral discs, and ligaments, which cannot be adequately visualized on plain radiographs or standard CT scans.

Question 1584

Topic: 6. Spine
An MRI is obtained for the 15-year-old male with suspected SCIWORA. The MRI confirms a spinal cord injury without radiographic abnormality. Given the findings on MRI and the diagnosis of SCIWORA, what is the best predictor of long-term neurologic outcome in this condition?
. Age at the time of injury
. Sex
. Mechanism of injury
. Neurologic status at time of presentation
. Socioeconomic status

Correct Answer & Explanation

. Neurologic status at time of presentation

Explanation

The correct answer is neurologic status at time of presentation. For patients with SCIWORA, the most significant predictor of long-term neurologic outcome is their neurologic status at the time of initial presentation. Patients with complete lesions (like this patient, classified as ASIA A) very rarely improve, while those with incomplete but severe spinal cord lesions may improve but often not to pre-injury levels. The extent of the initial neurological deficit is paramount in determining the prognosis.

Question 1585

Topic: 6. Spine

A 12-year-old is involved in a high-speed motor vehicle collision while wearing a lap-belt only. Radiographs reveal a bony Chance fracture of L2. Which of the following associated injuries has the highest incidence in this patient?

. Aortic transection
. Hollow viscus intra-abdominal injury
. Cervical spine facet dislocation
. Pelvic ring disruption
. Diaphragmatic rupture

Correct Answer & Explanation

. Hollow viscus intra-abdominal injury

Explanation

Chance fractures (flexion-distraction injuries) caused by lap belts are highly associated with intra-abdominal injuries, particularly to hollow organs such as the small bowel. Prompt general surgery evaluation is mandatory.

Question 1586

Topic: 6. Spine

A 35-year-old male presents with severe neck pain and right upper extremity weakness following a diving accident. Imaging reveals a right-sided unilateral facet dislocation at C5-C6. Which of the following neurological deficits is most likely present?

. Weakness in wrist extension and altered sensation over the thumb
. Weakness in elbow extension and altered sensation over the middle finger
. Weakness in shoulder abduction and altered sensation over the lateral deltoid
. Weakness in finger abduction and altered sensation over the little finger
. Complete loss of motor and sensory function below C5

Correct Answer & Explanation

. Weakness in wrist extension and altered sensation over the thumb

Explanation

A unilateral facet dislocation at C5-C6 typically impinges the exiting C6 nerve root on the ipsilateral side. C6 radiculopathy presents with weakness in wrist extension and altered sensation in the thumb and index finger.

Question 1587

Topic: 6. Spine

An 84-year-old male with severe baseline COPD sustains a Type II odontoid fracture after a ground-level fall. He is neurologically intact. Which of the following treatments provides the lowest morbidity and mortality for this specific patient?

. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 spinal fusion
. Hard cervical collar immobilization
. Prolonged bed rest with skeletal traction

Correct Answer & Explanation

. Posterior C1-C2 spinal fusion

Explanation

Elderly patients with Type II odontoid fractures have exceptionally high mortality and nonunion rates with halo vest immobilization. Posterior C1-C2 fusion provides the most reliable stabilization with lower morbidity compared to a halo in the elderly.

Question 1588

Topic: 6. Spine
A 70-year-old male with pre-existing cervical spondylosis presents after a hyperextension injury. He exhibits marked motor weakness in his upper extremities, particularly his hands, with relative sparing of his lower extremities. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-SΓ©quard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Cruciate paralysis

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome most commonly occurs in elderly patients with pre-existing cervical stenosis who sustain a hyperextension injury. It disproportionately affects the medially located cervical motor tracts, leading to upper extremity weakness greater than lower extremity weakness.

Question 1589

Topic: Thoracolumbar Spine & Deformity

A 25-year-old female presents after a fall from 10 feet. CT reveals an L1 burst fracture with 15 degrees of focal kyphosis and 30% canal compromise. She has normal neurological function, and MRI confirms the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Immediate operative decompression and fusion
. Treatment with a Thoracolumbosacral orthosis (TLSO)
. Percutaneous short-segment pedicle screw fixation
. Anterior corpectomy and cage placement
. Bed rest for 6 weeks without orthosis

Correct Answer & Explanation

. Treatment with a Thoracolumbosacral orthosis (TLSO)

Explanation

This patient has a TLICS score of 2 (Burst morphology = 2; Neuro intact = 0; PLC intact = 0). A score of 3 or less is an indication for non-operative management, typically with a TLSO brace and early mobilization.

Question 1590

Topic: 6. Spine

A 22-year-old male presents with tetraplegia following a C5 burst fracture. He is flaccid, areflexic, and lacks perianal sensation. Which of the following clinical signs marks the end of the spinal shock phase?

. Return of deep tendon reflexes in the biceps
. Return of voluntary anal sphincter contraction
. Return of the bulbocavernosus reflex
. Improvement in blood pressure and heart rate
. Return of the cremasteric reflex

Correct Answer & Explanation

. Return of the bulbocavernosus reflex

Explanation

Spinal shock is characterized by transient flaccidity and areflexia below the level of injury. The return of the bulbocavernosus reflex (an S2-S4 reflex arc) reliably indicates the end of spinal shock, allowing for accurate ASIA grading.

Question 1591

Topic: Thoracolumbar Spine & Deformity

A 30-year-old male falls from a ladder, sustaining an L1 burst fracture. CT shows 40% canal compromise. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

. Posterior spinal fusion from T11 to L3
. Anterior corpectomy and fusion
. Thoracolumbosacral orthosis (TLSO) brace
. Laminectomy and short-segment fixation
. Bed rest for 6 weeks followed by physical therapy

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) brace

Explanation

The TLICS score is 2 (1 point for compression mechanism, +1 point for burst component, 0 for intact PLC, 0 for intact neurologic status). A TLICS score of 3 or less is an indication for non-operative management, such as a TLSO brace.

Question 1592

Topic: Cervical Spine

An 80-year-old female sustains a low-energy fall from a standing height. CT of the cervical spine reveals a Type II odontoid fracture with 2 mm of posterior displacement. She is neurologically intact. Which of the following is the most appropriate initial management?

. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 fusion
. Rigid cervical collar
. Occipitocervical fusion

Correct Answer & Explanation

. Rigid cervical collar

Explanation

In elderly patients with a Type II odontoid fracture, conservative management with a rigid cervical collar is generally favored due to the high morbidity and mortality associated with surgery and halo vests. Nonunion may occur, but most patients achieve a stable, asymptomatic fibrous nonunion.

Question 1593

Topic: 6. Spine

A 30-year-old male is brought in obtunded following a severe motor vehicle collision. CT of the cervical spine demonstrates a right-sided unilateral C5-C6 facet dislocation. What is the most appropriate next step in management of the cervical spine injury?

. Immediate closed reduction with cranial traction
. MRI of the cervical spine
. Immediate posterior spinal fusion
. Application of a halo vest
. High-dose intravenous steroids

Correct Answer & Explanation

. MRI of the cervical spine

Explanation

In a patient with a cervical facet dislocation who is obtunded or neurologically unexaminable, an MRI must be obtained prior to reduction to rule out a compressive disc herniation. Attempting reduction in this setting could lead to irreversible spinal cord injury if a herniated disc is retropulsed.

Question 1594

Topic: Thoracolumbar Spine & Deformity

A 22-year-old male falls from a height and sustains an L1 burst fracture. He is neurologically intact. MRI demonstrates definitive rupture of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and recommended management?

. Score 2; nonoperative management in a TLSO
. Score 4; operative or nonoperative management
. Score 5; operative management
. Score 7; operative management
. Score 3; nonoperative management

Correct Answer & Explanation

. Score 5; operative management

Explanation

The TLICS score is calculated as follows: Burst fracture morphology (2 points), intact neurologic status (0 points), and ruptured PLC (3 points) for a total of 5 points. A score of 5 or greater indicates surgical stabilization is recommended.

Question 1595

Topic: Cervical Spine

An 82-year-old female presents with severe neck pain following a ground-level fall. Imaging reveals a Type II odontoid fracture with 3 mm of posterior displacement. She is neurologically intact but has severe medical comorbidities (ASA class IV). What is the most appropriate management?

. Rigid cervical collar
. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 fusion
. Transoral odontoidectomy

Correct Answer & Explanation

. Rigid cervical collar

Explanation

In elderly patients with significant comorbidities, surgical intervention carries high morbidity and mortality. Rigid cervical collar immobilization is often the preferred treatment for Type II odontoid fractures in this population, prioritizing functional recovery and patient survival.

Question 1596

Topic: 6. Spine

A 65-year-old male with underlying cervical spondylosis sustains a hyperextension injury to his neck in a rear-end collision. He presents with profound bilateral upper extremity motor weakness but retains ability to move his legs. What is the most likely pathological mechanism of this specific spinal cord injury syndrome?

. Hemisection of the spinal cord
. Infarction of the anterior spinal artery
. Pinching of the cord between a buckling ligamentum flavum and anterior osteophytes
. Traumatic avulsion of the cervical nerve roots
. Fracture through the pars interarticularis

Correct Answer & Explanation

. Pinching of the cord between a buckling ligamentum flavum and anterior osteophytes

Explanation

This patient has Central Cord Syndrome, classic for elderly patients with cervical spondylosis sustaining a hyperextension injury. The cord is acutely compressed between a buckling posterior ligamentum flavum and preexisting anterior cervical osteophytes, affecting central motor tracts.

Question 1597

Topic: Cervical Spine

An 82-year-old male with a history of COPD and osteoporosis sustains a Type II odontoid fracture after a ground-level fall. He complains of severe neck pain but remains neurologically intact. When considering treatment, which of the following management options is associated with the highest risk of mortality and severe complications in this specific patient demographic?

. Hard cervical collar immobilization
. Posterior C1-C2 instrumental fusion
. Halo vest immobilization
. Anterior odontoid screw fixation
. Soft cervical collar for comfort

Correct Answer & Explanation

. Halo vest immobilization

Explanation

Halo vest immobilization is relatively contraindicated in the elderly (often defined as >80 years) due to an unacceptably high risk of morbidity and mortality, primarily from severe respiratory complications and pin site infections. A hard cervical collar or posterior surgical stabilization are preferred alternatives.

Question 1598

Topic: Thoracolumbar Spine & Deformity

A 16-year-old male is brought to the emergency department after a high-speed motor vehicle collision where he was a restrained rear-seat passenger wearing a lap belt. Radiographs and CT imaging reveal a flexion-distraction injury of the lumbar spine (Chance fracture).

Which of the following associated injuries must be most aggressively ruled out in this patient?

. Aortic transection
. Intra-abdominal hollow viscus injury
. Diaphragmatic rupture
. Renal artery thrombosis
. Pelvic ring disruption

Correct Answer & Explanation

. Intra-abdominal hollow viscus injury

Explanation

Chance fractures (flexion-distraction injuries) sustained via a lap belt mechanism are highly associated with intra-abdominal pathology, particularly hollow viscus injuries (e.g., bowel perforation). These occur in up to 50% of cases and demand careful general surgery evaluation.

Question 1599

Topic: Thoracolumbar Spine & Deformity
Which type of spondylolisthesis is most commonly associated with a sacral spina bifida occulta and a trapezoidal L5 vertebral body?
. Type I Dysplastic
. Type II Isthmic
. Type III Degenerative
. Type IV Traumatic
. Type V Pathologic

Correct Answer & Explanation

. Type I Dysplastic

Explanation

Type I, or Dysplastic Spondylolisthesis, is a congenital anomaly characterized by malformed sacral facets, an elongated pars, and a trapezoidal L5 vertebral body, often associated with sacral spina bifida occulta. This morphology leads to an inherent instability that predisposes to anterior slippage. The other types have different underlying etiologies.

Question 1600

Topic: Thoracolumbar Spine & Deformity

What is the primary role of an oblique radiograph in the workup of spondylolisthesis?

. To assess overall spinal alignment and balance
. To visualize the pars interarticularis for a defect
. To measure the percentage of vertebral slip
. To evaluate disc height and endplate sclerosis
. To identify facet joint arthrosis

Correct Answer & Explanation

. To visualize the pars interarticularis for a defect

Explanation

Correct Answer: BOblique radiographs are specifically used to visualize the pars interarticularis, which appears as the 'neck' of the 'Scottie dog.' A defect or fracture in the pars ('collar on the Scottie dog') is indicative of an isthmic spondylolysis or spondylolisthesis. Other views (AP/Lateral) are better for alignment, slip percentage, and disc space evaluation.

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