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6. Spine MCQs

Practice Set 330 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 6581

Topic: 6. Spine

A 30-year-old male is involved in a motor vehicle collision. CT reveals bilateral pars interarticularis fractures of C2 with 4mm of anterior translation and severe angulation. According to the Levine-Edwards classification, this is a Type II fracture. What is the primary mechanism of injury?

. Axial loading
. Hyperextension and axial loading
. Hyperextension followed by rebound flexion
. Hyperflexion and rotation
. Lateral bending and shear

Correct Answer & Explanation

. Hyperextension followed by rebound flexion

Explanation

A Levine-Edwards Type II Hangman's fracture is typically caused by a hyperextension injury followed by rebound flexion. This combined mechanism disrupts the C2-C3 intervertebral disc and the posterior longitudinal ligament, leading to significant angulation.

Question 6582

Topic: 6. Spine

A 72-year-old male presents with significant neck stiffness. Radiographs demonstrate flowing ossification along the anterolateral aspect of 5 contiguous lower cervical and upper thoracic vertebrae, with preserved disc heights and no sacroiliac joint involvement. What is the most likely diagnosis?

. Ankylosing Spondylitis
. Ossification of the Posterior Longitudinal Ligament
. Diffuse Idiopathic Skeletal Hyperostosis (DISH)
. Scheuermann's Disease
. Degenerative Spondylosis

Correct Answer & Explanation

. Diffuse Idiopathic Skeletal Hyperostosis (DISH)

Explanation

Diffuse Idiopathic Skeletal Hyperostosis (DISH) is characterized by flowing anterolateral ossification of at least 4 contiguous vertebral bodies. Unlike Ankylosing Spondylitis, DISH features preserved disc heights and classically spares the sacroiliac joints.

Question 6583

Topic: 6. Spine

A 45-year-old male presents with severe acute low back pain, bilateral lower extremity radicular pain, and new-onset urinary retention. Examination reveals perineal anesthesia and decreased anal sphincter tone. To maximize the likelihood of functional sphincter recovery, surgical decompression should ideally be performed within what timeframe?

. 6 hours
. 12 hours
. 24 hours
. 48 hours
. 72 hours

Correct Answer & Explanation

. 48 hours

Explanation

Cauda equina syndrome is a surgical emergency. Literature suggests that decompression within 48 hours of symptom onset maximizes the likelihood of significant bowel and bladder functional recovery.

Question 6584

Topic: Cervical Spine

A 78-year-old female sustains a fall and is diagnosed with a displaced Type II odontoid fracture. She has a history of mild COPD and hypertension. Which of the following management strategies offers the highest rate of bony union for this specific patient?

. Halo vest immobilization
. Rigid cervical collar for 12 weeks
. Anterior odontoid screw fixation
. Posterior C1-C2 instrumentation and fusion
. C1-C2 transarticular screw fixation without bone grafting

Correct Answer & Explanation

. Posterior C1-C2 instrumentation and fusion

Explanation

In elderly patients (age > 70) with displaced Type II odontoid fractures, conservative management (halo or collar) has a high nonunion rate and significant morbidity. Posterior C1-C2 instrumentation and fusion offers the highest union rates and functional outcomes.

Question 6585

Topic: Thoracolumbar Spine & Deformity

In the surgical management of Adult Spinal Deformity, restoring sagittal balance is a primary goal. Which of the following pelvic parameters is a fixed, position-independent morphological measurement of the pelvis?

. Pelvic Tilt (PT)
. Sacral Slope (SS)
. Pelvic Incidence (PI)
. Lumbar Lordosis (LL)
. Sagittal Vertical Axis (SVA)

Correct Answer & Explanation

. Pelvic Incidence (PI)

Explanation

Pelvic incidence is a fixed morphological parameter that dictates the necessary amount of lumbar lordosis (LL = PI ยฑ 9 degrees). Pelvic tilt and sacral slope are dynamic parameters that change with patient positioning.

Question 6586

Topic: 6. Spine

A 28-year-old female presents with severe right leg radicular pain. MRI reveals a far-lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed, and what is the expected motor deficit?

. L4 root; weakness in ankle dorsiflexion
. L4 root; weakness in knee extension
. L5 root; weakness in great toe extension
. L5 root; weakness in ankle plantarflexion
. S1 root; weakness in ankle plantarflexion

Correct Answer & Explanation

. L4 root; weakness in knee extension

Explanation

A far-lateral (extraforaminal) disc herniation at L4-L5 compresses the exiting L4 nerve root. L4 compression classically presents with weakness in knee extension (quadriceps) and a diminished patellar reflex.

Question 6587

Topic: 6. Spine

A 45-year-old male presents with severe right leg pain. Examination shows 4/5 weakness in right knee extension and a diminished patellar reflex. MRI reveals a far lateral disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

Far lateral (extraforaminal) disc herniations compress the exiting nerve root at the same level. Therefore, an L4-L5 far lateral disc herniation will compress the L4 nerve root, leading to knee extension weakness and a decreased patellar reflex.

Question 6588

Topic: 6. Spine
A 70-year-old male with known cervical spondylosis presents after a hyperextension injury. He has 2/5 motor strength in his upper extremities and 4/5 in his lower extremities, with spotty sensory loss. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Sรฉquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Spinal shock

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs after a hyperextension injury in a patient with pre-existing cervical stenosis. It is characterized by disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 6589

Topic: Cervical Spine

A 78-year-old female sustains a Type II odontoid fracture after a ground-level fall. Displacement is 2 mm, and she is neurologically intact. Given her age and comorbidities, what is the most appropriate initial management?

. Halo vest immobilization
. Hard cervical collar
. Anterior odontoid screw fixation
. Posterior C1-C2 fusion
. Minerva cast

Correct Answer & Explanation

. Hard cervical collar

Explanation

In elderly patients (>65 years) with Type II odontoid fractures, rigid collar immobilization is preferred over a halo vest due to the high morbidity and mortality associated with halo placement. Surgery is reserved for nonunions or highly displaced fractures.

Question 6590

Topic: 6. Spine

A 22-year-old female wearing a lap-belt during a high-speed motor vehicle collision presents with a seatbelt sign across her abdomen. Spine radiographs reveal a flexion-distraction (Chance) fracture at L1. What associated injury must be urgently ruled out?

. Aortic transection
. Diaphragmatic rupture
. Hollow viscus injury
. Renal artery thrombosis
. Pelvic ring disruption

Correct Answer & Explanation

. Hollow viscus injury

Explanation

Chance fractures are flexion-distraction injuries commonly caused by seatbelts acting as a fulcrum. They carry a high risk (up to 50%) of associated intra-abdominal injuries, particularly hollow viscus (bowel) injuries.

Question 6591

Topic: 6. Spine

A 55-year-old male with long-standing ankylosing spondylitis presents with neck pain after a minor fall. He is neurologically intact. Initial lateral cervical spine X-rays are reported as normal. What is the most appropriate next step in management?

. Discharge with NSAIDs
. Soft cervical collar
. Flexion-extension radiographs
. CT or MRI of the entire cervical spine
. Cervical traction

Correct Answer & Explanation

. CT or MRI of the entire cervical spine

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable "chalk stick" fractures even from minor trauma. A normal X-ray does not rule out a fracture; advanced imaging (CT or MRI) is mandatory to evaluate for occult fractures or epidural hematomas.

Question 6592

Topic: Thoracolumbar Spine & Deformity

In evaluating a patient with adult spinal deformity, achieving appropriate sagittal balance is a primary surgical goal. Which of the following spinopelvic parameters is morphological and remains fixed regardless of patient positioning?

. Pelvic tilt (PT)
. Sacral slope (SS)
. Lumbar lordosis (LL)
. Pelvic incidence (PI)
. Sagittal vertical axis (SVA)

Correct Answer & Explanation

. Pelvic incidence (PI)

Explanation

Pelvic incidence (PI) is a fixed morphological parameter unique to each individual's pelvic anatomy. As the pelvis retroverts or anteverts to compensate for deformity, pelvic tilt and sacral slope change, but PI remains constant.

Question 6593

Topic: 6. Spine

A 50-year-old diabetic male presents with severe back pain, fevers, and progressive lower extremity weakness. MRI reveals an L3-L4 ventral epidural abscess. Laboratory tests show elevated ESR and CRP. What is the definitive management?

. Intravenous antibiotics alone
. CT-guided aspiration
. Lumbar laminectomy and debridement
. Anterior corpectomy and strut grafting
. Posterior spinal fusion alone

Correct Answer & Explanation

. Lumbar laminectomy and debridement

Explanation

The presence of a progressive neurologic deficit in the setting of a spinal epidural abscess is an absolute indication for urgent surgical decompression, typically via laminectomy and debridement. IV antibiotics alone are reserved for patients without neurologic deficits.

Question 6594

Topic: 6. Spine
A 14-year-old gymnast presents with chronic mechanical low back pain. Radiographs demonstrate an isthmic L5-S1 spondylolisthesis with 60% anterior translation. What is the Meyerding grade and recommended treatment?
. Grade II, non-operative management
. Grade II, posterior spinal fusion
. Grade III, posterior spinal fusion
. Grade III, pars repair
. Grade IV, anterior lumbar interbody fusion

Correct Answer & Explanation

. Grade III, posterior spinal fusion

Explanation

Meyerding Grade III corresponds to 50-75% translation. In pediatric patients, high-grade slips (>50%) have a high risk of progression and neurologic compromise, warranting surgical stabilization with posterior spinal fusion.

Question 6595

Topic: Cervical Spine

A 21-year-old collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction. Biomechanically, which bundle of the native UCL is the primary restraint to valgus stress at 30 degrees of elbow flexion, and therefore the primary target of this reconstruction?

. Anterior band of the anterior bundle
. Posterior band of the anterior bundle
. Posterior bundle
. Transverse ligament (Cooper's ligament)
. Radial collateral ligament

Correct Answer & Explanation

. Anterior band of the anterior bundle

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress of the elbow. It is subdivided into the anterior and posterior bands. The anterior band is the primary restraint to valgus stress from 0 to 90 degrees of flexion, while the posterior band becomes more taut and clinically significant in deeper flexion (typically >90-120 degrees).

Question 6596

Topic: Cervical Spine

A 21-year-old baseball pitcher presents with medial elbow pain during the late cocking phase of throwing. He is diagnosed with a severe ulnar collateral ligament (UCL) tear. Which bundle of the UCL acts as the primary restraint to valgus stress at 90 degrees of elbow flexion?

. Anterior bundle
. Posterior bundle
. Transverse ligament
. Radial collateral ligament
. Lateral ulnar collateral ligament

Correct Answer & Explanation

. Anterior bundle

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress of the elbow between 30 and 120 degrees of flexion. It is the bundle most frequently injured in overhead throwing athletes.

Question 6597

Topic: 6. Spine

A 70-year-old woman is evaluated for a primary THA. Standing and sitting lateral spinopelvic radiographs reveal a change in pelvic tilt of 5 degrees. How does this stiff spinopelvic relationship influence acetabular component positioning?

. The cup should be placed in more anteversion to compensate for the lack of dynamic clearance during sitting
. The cup should be placed in standard safe zone targets as the pelvis adapts dynamically
. The cup should be placed in less anteversion to prevent posterior dislocation
. The femur should be prepared with increased anteversion to compensate
. A dual mobility component is strictly contraindicated in this scenario

Correct Answer & Explanation

. The cup should be placed in more anteversion to compensate for the lack of dynamic clearance during sitting

Explanation

A stiff spine (change in pelvic tilt < 10 degrees) fails to dynamically retrovert the pelvis during sitting, leading to anterior impingement. The acetabular cup must be placed in slightly more anteversion to accommodate flexion and prevent posterior dislocation.

Question 6598

Topic: 6. Spine

A 70-year-old woman with a multi-level lumbar spinal fusion from L2 to the sacrum is scheduled for a primary total hip arthroplasty (THA). Preoperative lateral pelvic radiographs reveal a stiff spinopelvic junction with an inability to increase pelvic tilt during sitting. To minimize the risk of dislocation in this patient, how should the acetabular component positioning be modified?

. Decrease the cup anteversion to 0 degrees
. Increase the cup anteversion and inclination
. Target the standard Lewinnek safe zone strictly
. Decrease the cup inclination to 30 degrees
. Use a constrained liner regardless of cup position

Correct Answer & Explanation

. Increase the cup anteversion and inclination

Explanation

Patients with a fused or stiff lumbar spine fail to increase posterior pelvic tilt when sitting, predisposing them to anterior impingement and posterior dislocation. Increasing cup anteversion and inclination compensates for the lack of dynamic spinopelvic mobility and reduces this risk.

Question 6599

Topic: 6. Spine

A 35-year-old male is involved in a high-speed MVC resulting in a traumatic spondylolisthesis of the axis (Hangman's fracture). What is the primary mechanism of injury for the classic Levine-Edwards Type II fracture?

. Hyperflexion and compression
. Hyperextension and axial loading
. Lateral bending
. Rotational shear
. Distraction and extension

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A Hangman's fracture (traumatic spondylolisthesis of C2) is classically caused by hyperextension and axial loading. This forces the pars interarticularis to fracture against the pedicle of C3.

Question 6600

Topic: Cervical Spine

A 21-year-old collegiate pitcher undergoes ulnar collateral ligament (UCL) reconstruction using a palmaris longus autograft. Which bundle of the native UCL is the primary restraint to valgus stress between 30 and 120 degrees of elbow flexion, and thus the target for reconstruction?

. Posterior bundle
. Anterior band of the anterior bundle
. Posterior band of the anterior bundle
. Transverse ligament
. Lateral ulnar collateral ligament

Correct Answer & Explanation

. Anterior band of the anterior bundle

Explanation

The anterior bundle of the UCL is the primary stabilizer against valgus stress. Specifically, its anterior band is tight in extension and the primary restraint up to 120 degrees of flexion, making it the critical structure to reconstruct.

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