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6. Spine MCQs

Practice Set 91 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 1801

Topic: 6. Spine

A 40-year-old patient with a C6-C7 bilateral facet dislocation and a large traumatic disc herniation on MRI is scheduled for an anterior cervical discectomy and fusion (ACDF). During the approach, the surgeon identifies the internervous plane. Which anatomical structures define this plane for a standard Smith-Robinson approach?

. Between the longus colli muscles and the prevertebral fascia.
. Between the sternocleidomastoid muscle and the carotid sheath laterally, and the strap muscles, trachea, and esophagus medially.
. Between the platysma muscle and the superficial layer of the deep cervical fascia.
. Between the anterior longitudinal ligament and the posterior longitudinal ligament.
. Between the sympathetic chain and the vertebral artery.

Correct Answer & Explanation

. Between the sternocleidomastoid muscle and the carotid sheath laterally, and the strap muscles, trachea, and esophagus medially.

Explanation

Correct Answer: BThe standard Smith-Robinson anterior cervical approach utilizes an internervous plane to access the cervical spine. This plane is developed between the sternocleidomastoid muscle and the carotid sheath (containing the common carotid artery, internal jugular vein, and vagus nerve) laterally, and the strap muscles (sternohyoid, sternothyroid, omohyoid), trachea, and esophagus medially. This approach minimizes muscle transection and allows for safe access to the prevertebral fascia and anterior cervical spine.Option A describes a deeper plane after the prevertebral fascia is exposed. Option C describes the initial incision through superficial layers. Options D and E describe structures within or adjacent to the vertebral column, not the primary internervous plane for the approach.

Question 1802

Topic: 6. Spine

A 60-year-old patient with a C5-C6 bilateral facet dislocation, without evidence of disc herniation on MRI, undergoes a posterior approach for reduction and stabilization. The surgeon plans to perform lateral mass screw fixation.

Based on the provided image and standard techniques, which of the following describes the Magerl technique for lateral mass screw placement at C5?

. Starting point at the exact center of the lateral mass, with a straight anterior trajectory.
. Starting point 1 mm medial and 1 mm cephalad to the center of the lateral mass, with a 25-degree lateral and 20-30 degree cephalad trajectory.
. Starting point 1 mm lateral and 1 mm caudal to the center of the lateral mass, with a 10-degree medial and 10-degree caudal trajectory.
. Starting point at the base of the spinous process, directing the screw laterally into the pedicle.
. Starting point at the junction of the lamina and the superior articular process, aiming towards the vertebral body.

Correct Answer & Explanation

. Starting point 1 mm medial and 1 mm cephalad to the center of the lateral mass, with a 25-degree lateral and 20-30 degree cephalad trajectory.

Explanation

Correct Answer: BThe Magerl technique for lateral mass screw placement is a widely accepted method designed to maximize screw purchase while minimizing the risk of neurovascular injury. The starting point is typically 1 millimeter medial and 1 millimeter cephalad to the center of the lateral mass. The trajectory is 25 degrees lateral (to avoid the vertebral artery, which lies anterior and medial to the lateral mass) and parallel to the superior articular facet in the sagittal plane (typically 20 to 30 degrees cephalad, avoiding the exiting nerve root). This trajectory aims to engage the thickest part of the lateral mass.Option A describes the Roy-Camille technique, which uses a central starting point and a straight anterior trajectory. The other options describe incorrect starting points or trajectories that would increase the risk of vertebral artery or nerve root injury.

Question 1803

Topic: Cervical Spine

A 48-year-old male undergoes an anterior cervical discectomy and fusion (ACDF) for a C5-C6 bilateral facet dislocation. Postoperatively, he develops hoarseness and difficulty swallowing. Which of the following complications is most likely responsible for his symptoms, and what is its typical management?

. C5 nerve root palsy; typically managed with immediate re-exploration and decompression.
. Vertebral artery injury; requires emergent endovascular embolization.
. Recurrent laryngeal nerve palsy and dysphagia; often transient, managed conservatively with speech therapy.
. Epidural hematoma; requires emergent MRI and surgical evacuation.
. Hardware failure; requires revision surgery with extension of the fusion construct.

Correct Answer & Explanation

. Recurrent laryngeal nerve palsy and dysphagia; often transient, managed conservatively with speech therapy.

Explanation

Correct Answer: CHoarseness is a classic symptom of recurrent laryngeal nerve (RLN) palsy, which can occur during an anterior cervical approach due to retraction or direct injury to the nerve. Dysphagia (difficulty swallowing) is also a common complication, often transient, resulting from esophageal retraction and irritation during the anterior approach. Both complications are relatively common (RLN palsy 1-5%, dysphagia 10-30%) and are usually transient, resolving spontaneously within weeks to months. Management is typically conservative, involving speech therapy evaluation for dysphagia and vocal cord assessment for hoarseness. Severe or persistent cases may require further intervention.Option A (C5 nerve root palsy) presents as deltoid and biceps weakness, not hoarseness or dysphagia. Option B (vertebral artery injury) would present with signs of posterior circulation stroke or significant hemorrhage. Option D (epidural hematoma) would typically cause acute neurological deterioration, not isolated hoarseness and dysphagia. Option E (hardware failure) is a long-term mechanical complication, not an acute postoperative neurological or soft tissue issue.

Question 1804

Topic: 6. Spine

A 22-year-old patient with an ASIA B C6 incomplete spinal cord injury following a bilateral C6-C7 facet dislocation undergoes successful surgical stabilization within 12 hours of injury. In the immediate postoperative period, what is the most critical hemodynamic management goal to optimize spinal cord perfusion and minimize secondary injury?

. Maintain systolic blood pressure (SBP) below 100 mmHg to reduce intracranial pressure.
. Maintain mean arterial pressure (MAP) greater than 85 mmHg for at least 7 days.
. Administer prophylactic vasopressors to keep heart rate above 120 bpm.
. Restrict fluid intake to prevent pulmonary edema.
. Initiate deep vein thrombosis (DVT) prophylaxis only after 7 days to avoid bleeding complications.

Correct Answer & Explanation

. Maintain mean arterial pressure (MAP) greater than 85 mmHg for at least 7 days.

Explanation

Correct Answer: BCurrent guidelines for the management of acute spinal cord injury (SCI) emphasize maintaining adequate spinal cord perfusion to minimize the penumbra of ischemic secondary injury. This is achieved by maintaining the Mean Arterial Pressure (MAP) greater than 85 mmHg for at least 7 days post-injury. This hemodynamic target helps ensure sufficient blood flow to the injured spinal cord, which is particularly vulnerable to ischemia.Option A is incorrect; maintaining a low SBP would compromise spinal cord perfusion. Option C is incorrect; heart rate is not the primary hemodynamic target for SCI. Option D is incorrect; fluid restriction could lead to hypovolemia and compromise MAP. Option E is incorrect; DVT prophylaxis should be initiated within 72 hours of surgery, provided there is no evidence of expanding epidural hematoma, to prevent thromboembolic complications, which are common in SCI patients.

Question 1805

Topic: 6. Spine

A 70-year-old patient presents after a ground-level fall with a bilateral C4-C5 facet dislocation. Imaging confirms complete disruption of the posterior ligamentous complex. Neurological examination reveals an ASIA D incomplete spinal cord injury. Based on the Subaxial Cervical Spine Injury Severity (SLIC) score, what is the minimum score assigned to this injury, and what does it indicate regarding management?

. 4 points, indicating non-operative management with a halo vest.
. 6 points, suggesting a strong consideration for surgical intervention.
. 8 points, mandating surgical stabilization.
. 10 points, requiring a combined anterior and posterior approach.
. 3 points, allowing for observation and physical therapy.

Correct Answer & Explanation

. 8 points, mandating surgical stabilization.

Explanation

Correct Answer: CThe Subaxial Cervical Spine Injury Severity (SLIC) score is a validated algorithm for surgical decision-making. For a bilateral facet dislocation, the score components are:Injury Morphology:Bilateral facet dislocation is considered a translational/rotational injury, scoring 3 points.Discoligamentous Complex Integrity:Complete disruption of the posterior ligamentous complex scores 2 points.Neurological Status:An ASIA D incomplete spinal cord injury scores 3 points.Therefore, the total SLIC score for this patient is 3 (morphology) + 2 (PLC) + 3 (neurological status) = 8 points. A SLIC score of 5 or greater mandates surgical intervention. Thus, a score of 8 points strongly mandates surgical stabilization.

Question 1806

Topic: 6. Spine

A patient presents with a bilateral C5-C6 facet dislocation. On lateral cervical spine radiography, which of the following findings is most characteristic of this injury type, indicating profound instability?

. Less than 25% anterior translation of the superior vertebral body.
. Widening of the interspinous distance at the injured level, but intact facet joints.
. Significant anterior translation of the superior vertebral body, often exceeding 50% of the vertebral body width.
. A "teardrop" fracture of the anterior inferior aspect of the vertebral body with minimal displacement.
. Isolated fracture of the spinous process with no associated ligamentous injury.

Correct Answer & Explanation

. Significant anterior translation of the superior vertebral body, often exceeding 50% of the vertebral body width.

Explanation

Correct Answer: CBilateral cervical facet dislocation is characterized by profound instability due to complete disruption of the posterior ligamentous complex. Radiographically, this manifests as significant anterior translation of the superior vertebral body on the inferior one, often exceeding 50% of the vertebral body width on lateral radiography. The inferior articular processes of the superior vertebra translate anteriorly and superiorly over the superior articular processes of the inferior vertebra, ultimately dropping into the intervertebral foramina, creating a locked configuration.Option A describes less severe instability. Option B describes a purely ligamentous injury without facet dislocation. Option D describes a flexion teardrop fracture, which is a different injury pattern. Option E describes a stable injury, which is not characteristic of a bilateral facet dislocation.

Question 1807

Topic: 6. Spine
The management of acute spinal cord injury (SCI) associated with bilateral cervical facet dislocation has evolved significantly. Which landmark study provided compelling evidence supporting early surgical decompression (within 24 hours of injury) for improved neurological outcomes in patients with SCI?
. The Panjabi and White biomechanical studies on cervical spine instability.
. The Allen and Ferguson classification system for cervical spine injuries.
. The Subaxial Cervical Spine Injury Severity (SLIC) score development.
. The Surgical Timing in Acute Spinal Cord Injury Study (STASCIS).
. The randomized controlled trials comparing halo vest immobilization to surgical fixation.

Correct Answer & Explanation

. The Surgical Timing in Acute Spinal Cord Injury Study (STASCIS).

Explanation

The Surgical Timing in Acute Spinal Cord Injury Study (STASCIS) was a pivotal prospective, multicenter cohort study that demonstrated the significant benefit of early surgical decompression (within 24 hours of injury) in patients with acute spinal cord injury. The study found that early intervention resulted in significantly improved neurological outcomes at 6-month follow-up compared to delayed decompression, without an increase in complication rates. This study fundamentally shifted the paradigm towards emergent surgical intervention for spinal cord injuries, including those associated with bilateral facet dislocations.

Question 1808

Topic: 6. Spine

A 70-year-old female undergoes open reduction and internal fixation of a displaced two-part surgical neck fracture. She is placed in the beach chair position for the procedure, as depicted in the general surgical setup shown in the image. Which of the following is a critical precaution to take when positioning a patient in the beach chair position for shoulder surgery?

. Ensuring the operative arm is tightly adducted to prevent nerve stretch.
. Monitoring blood pressure closely for potential cerebral hypoperfusion ('beach chair hypotension').
. Placing an axillary roll under the dependent axilla to prevent brachial plexus compression.
. Maintaining the patient in a steep Trendelenburg position to improve venous return.
. Securing the head in maximal extension to facilitate airway management.

Correct Answer & Explanation

. Monitoring blood pressure closely for potential cerebral hypoperfusion ('beach chair hypotension').

Explanation

Correct Answer: BThe case content, under 'Patient Positioning - Beach Chair Position,' explicitly states: 'Precautions: Ensure adequate padding to all pressure points, especially the contralateral elbow, sacrum, and heels. Monitor blood pressure closely for potential cerebral hypoperfusion ('beach chair hypotension').'Option A (Ensuring the operative arm is tightly adducted to prevent nerve stretch):The operative arm is typically draped free to allow full manipulation, and tight adduction is not a standard precaution; rather, care is taken to avoid excessive traction or positioning that could stretch nerves.Option C (Placing an axillary roll under the dependent axilla to prevent brachial plexus compression):An axillary roll is a critical precaution for the lateral decubitus position, not typically for the beach chair position where the patient is semi-recumbent.Option D (Maintaining the patient in a steep Trendelenburg position to improve venous return):The beach chair position often involves a reverse Trendelenburg (head up) to reduce blood loss, not a steep Trendelenburg.Option E (Securing the head in maximal extension to facilitate airway management):The head is typically secured in a neutral or slightly flexed position, often in a horseshoe headrest, to protect the cervical spine and prevent nerve injury, not maximal extension.

Question 1809

Topic: 6. Spine

A 35-year-old male is evaluated in the emergency department following a motorcycle collision. Imaging demonstrates a unilateral facet dislocation at C5-C6. Which of the following best describes the primary biomechanical mechanism responsible for this specific injury pattern?

. Axial loading with hyper-extension
. Flexion-distraction with rotation
. Pure axial loading
. Lateral bending with severe extension
. Hyper-flexion with compression

Correct Answer & Explanation

. Flexion-distraction with rotation

Explanation

Unilateral facet dislocations of the cervical spine typically result from a combined mechanism of flexion, distraction, and rotation. This causes one inferior articular process to ride forward and over the superior articular process of the vertebra below.

Question 1810

Topic: 6. Spine

A 24-year-old male sustains a traumatic spondylolisthesis of C2 (Hangman's fracture). Imaging shows a Levine-Edwards Type IIA fracture characterized by severe angulation with minimal translation. What is the most appropriate initial management step regarding skeletal traction?

. Immediate application of 15 lbs of cervical traction
. Gradual traction starting at 5 lbs, increasing serially
. Application of traction in severe flexion
. Strict avoidance of skeletal traction
. Application of traction in severe extension

Correct Answer & Explanation

. Strict avoidance of skeletal traction

Explanation

Levine-Edwards Type IIA Hangman's fractures result from flexion-distraction and have a disrupted C2-C3 intervertebral disc. Skeletal traction is strictly contraindicated as it will further distract the injury and can cause severe neurologic compromise.

Question 1811

Topic: 6. Spine

A trauma patient presents with an inability to move his lower extremities and severe weakness in his upper extremities following a C5 burst fracture. Upon examination, he has intact perianal sensation and voluntary anal sphincter contraction, but motor function below the level of injury is absent. How is this spinal cord injury classified according to the ASIA Impairment Scale?

. ASIA A
. ASIA B
. ASIA C
. ASIA D
. ASIA E

Correct Answer & Explanation

. ASIA B

Explanation

The presence of sensory or motor function in the lowest sacral segments (S4-S5) defines the injury as incomplete. Since sensory function is preserved (sacral sparing) but no motor function is preserved below the neurologic level, it is classified as ASIA B.

Question 1812

Topic: 6. Spine

A 28-year-old alert and cooperative male presents with severe neck pain and a unilateral C6-C7 facet dislocation following a sports injury. His neurological examination is completely normal. What is the current recommended standard of care regarding the timing of MRI and attempted closed reduction?

. MRI must be obtained prior to any reduction attempt to rule out disc herniation
. Immediate open reduction and internal fixation without MRI or closed reduction
. Awake closed reduction via skeletal traction should be performed without delaying for an MRI
. Closed reduction under general anesthesia followed by MRI
. Application of a hard collar and discharge with outpatient MRI

Correct Answer & Explanation

. Awake closed reduction via skeletal traction should be performed without delaying for an MRI

Explanation

In an awake, cooperative, and neurologically intact patient with a cervical facet dislocation, rapid closed reduction via skeletal traction is safe and recommended without the need for a pre-reduction MRI. MRI is indicated prior to reduction only in obtunded or uncooperative patients.

Question 1813

Topic: 6. Spine

A 22-year-old female is brought to the trauma bay after a high-speed MVC. Lateral cervical spine radiographs raise suspicion for atlanto-occipital dissociation (AOD). Which of the following radiographic measurements is most diagnostic of this condition?

. Atlantodens interval (ADI) greater than 3 mm
. Basion-dental interval (BDI) greater than 12 mm
. Power's ratio less than 1.0
. Prevertebral soft tissue swelling of 5 mm at C2
. Lateral mass overhang greater than 6.9 mm

Correct Answer & Explanation

. Basion-dental interval (BDI) greater than 12 mm

Explanation

The Rule of 12 (Harris lines) is used to diagnose atlanto-occipital dissociation. A basion-dental interval (BDI) or basion-axial interval (BAI) > 12 mm on a plain lateral radiograph or sagittal CT reconstruction is highly indicative of AOD.

Question 1814

Topic: Cervical Spine



A 30-year-old male sustains a burst fracture of the atlas (Jefferson fracture) after a diving accident. On the open-mouth odontoid radiograph, the combined overhang of the C1 lateral masses on C2 is measured at 8 mm. What does this measurement indicate regarding the integrity of the stabilizing ligaments?

. The alar ligament is ruptured
. The apical ligament is ruptured
. The transverse ligament is intact
. The transverse ligament is likely ruptured
. The tectorial membrane is ruptured

Correct Answer & Explanation

. The transverse ligament is likely ruptured

Explanation

According to the Rule of Spence, a combined lateral mass overhang of C1 on C2 greater than 6.9 mm on an AP open-mouth radiograph implies a rupture of the transverse ligament. This indicates a highly unstable C1 ring injury.

Question 1815

Topic: 6. Spine

A 40-year-old male presents with a cervical spine injury. CT and MRI reveal a non-displaced unilateral facet fracture, a disrupted posterior ligamentous complex, and he is neurologically intact. Using the Subaxial Cervical Spine Injury Classification (SLIC) system, what is his total score and the generally recommended treatment?

. Score 2; Non-operative management
. Score 3; Indeterminate management
. Score 4; Surgical management
. Score 5; Surgical management
. Score 6; Surgical management

Correct Answer & Explanation

. Score 3; Indeterminate management

Explanation

In the SLIC system, a facet fracture (morphology) is 1 point, disrupted discoligamentous complex (DLC) is 2 points, and intact neurologic status is 0 points. A total score of 3 generally indicates indeterminate management, often treated non-operatively in a collar depending on surgeon preference.

Question 1816

Topic: 6. Spine

A 65-year-old male with long-standing ankylosing spondylitis presents to the emergency department after a minor trip and fall. He complains of severe neck pain but is neurologically intact. CT reveals a through-and-through fracture at the C5-C6 level. What is the most appropriate definitive management for this patient?

. Hard cervical collar for 12 weeks
. Halo vest immobilization
. Anterior cervical discectomy and fusion (ACDF) strictly at C5-C6
. Long segment posterior cervical instrumentation and fusion
. Short segment posterior fusion restricted to C5-C6

Correct Answer & Explanation

. Long segment posterior cervical instrumentation and fusion

Explanation

Fractures in the ankylosed spine are highly unstable "chalk stick" type injuries and behave like long-bone fractures. Non-operative management or short-segment fusions have unacceptable failure rates; long-segment posterior instrumentation and fusion is the standard of care.

Question 1817

Topic: 6. Spine

A 38-year-old male sustains a severe cervical spine trauma resulting in a C4-C5 bilateral facet dislocation. In addition to spinal cord compromise, which of the following vascular injuries is most commonly associated with this specific type of high-energy cervical trauma?

. Internal carotid artery dissection
. External carotid artery pseudoaneurysm
. Vertebral artery occlusion or intimal tear
. Thyrocervical trunk avulsion
. Jugular vein thrombosis

Correct Answer & Explanation

. Vertebral artery occlusion or intimal tear

Explanation

Vertebral artery injury is highly associated with cervical spine trauma involving subluxation, facet dislocations, and fractures extending into the transverse foramen. CT angiography is commonly recommended to screen for occlusion, dissection, or intimal tears in these patients.

Question 1818

Topic: Cervical Spine

An 82-year-old male presents with severe neck pain following a ground-level fall. Imaging reveals a Type II odontoid fracture with 2 mm of posterior displacement. He has multiple severe medical comorbidities, including advanced COPD and congestive heart failure. Based on current literature for this specific demographic, what is the most appropriate initial management?

. Application of a halo vest
. Posterior C1-C2 instrumented fusion
. Rigid cervical collar immobilization
. Anterior odontoid screw fixation
. Occipitocervical fusion

Correct Answer & Explanation

. Rigid cervical collar immobilization

Explanation

In elderly patients with severe medical comorbidities, Type II odontoid fractures are increasingly managed non-operatively with a rigid cervical collar due to high morbidity and mortality associated with surgery and halo vests. Despite higher nonunion rates, clinical outcomes and survival are often equivalent to or better than aggressive surgical intervention in this high-risk group.

Question 1819

Topic: 6. Spine

A 24-year-old female presents after a rollover motor vehicle collision. Lateral cervical spine radiographs demonstrate an anterolisthesis of C5 on C6 of approximately 25%. What is the most likely mechanism of injury leading to this specific radiologic finding?

. Hyperextension and axial loading
. Hyperflexion and distraction
. Flexion and rotation
. Extension and rotation
. Axial loading and lateral bending

Correct Answer & Explanation

. Flexion and rotation

Explanation

Unilateral facet dislocations typically result from a mechanism involving flexion combined with rotation. Radiographically, they classically present with less than 50% anterior translation of the vertebral body, whereas bilateral facet dislocations (hyperflexion-distraction injuries) present with 50% or more anterior translation.

Question 1820

Topic: 6. Spine

A 68-year-old male with pre-existing cervical spondylosis presents after sustaining a hyperextension injury to his neck in a low-speed collision. He demonstrates profound motor weakness in his hands and upper extremities, but retains functional strength in his lower extremities. Perianal sensation is intact. Which of the following best describes the underlying pathophysiology of his neurological deficit?

. Disruption of the anterior spinal artery leading to ischemia
. Ischemic injury isolated to the lateral corticospinal tracts
. Central gray matter hemorrhage and edema due to cord pinching
. Avulsion of the cervical nerve roots
. Compression of the posterior columns by the ligamentum flavum

Correct Answer & Explanation

. Central gray matter hemorrhage and edema due to cord pinching

Explanation

This patient has Central Cord Syndrome, which classically occurs in older patients with cervical spondylosis who sustain a hyperextension injury. The mechanism involves pinching of the spinal cord between a bulging disc/osteophytes anteriorly and buckling ligamentum flavum posteriorly, leading to central gray matter hemorrhage and edema that disproportionately affects the medially located cervical motor tracts.

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