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6. Spine MCQs

Practice Set 170 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 3381

Topic: Thoracolumbar Spine & Deformity

In the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following variables is assigned the highest individual point value?

. Burst fracture morphology
. Complete neurologic deficit
. Disruption of the posterior ligamentous complex
. Distraction morphology
. Incomplete neurologic deficit

Correct Answer & Explanation

. Distraction morphology

Explanation

The TLICS system assigns points based on morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. Distraction morphology is assigned 4 points, making it the highest single point value in the scoring system. For comparison: translation/rotation morphology is 3 points, burst is 2; complete neurologic deficit is 2, incomplete is 3; and definite PLC disruption is 3 points.

Question 3382

Topic: 6. Spine

In the preoperative planning for a long spinal fusion to correct adult spinal deformity, achieving a harmonious sagittal profile is a primary objective. According to Schwab's criteria, the target postoperative Lumbar Lordosis (LL) should be within what range relative to the patient's Pelvic Incidence (PI)?

. Within +/- 2 degrees of PI
. Within +/- 10 degrees of PI
. Within +/- 20 degrees of PI
. LL should be roughly double the PI
. LL should be roughly half the PI

Correct Answer & Explanation

. Within +/- 10 degrees of PI

Explanation

The SRS-Schwab adult spinal deformity classification emphasizes the importance of spinopelvic parameters. The primary goal for restoring sagittal balance is to achieve a Lumbar Lordosis (LL) that is proportional to the Pelvic Incidence (PI), specifically targeting a mismatch of less than 10 degrees (PI minus LL < 10 degrees).

Question 3383

Topic: 6. Spine

A 24-year-old male is brought to the emergency department after a high-speed motor vehicle collision in which he was wearing a lap-belt only. Radiographs and CT of the lumbar spine reveal a flexion-distraction injury (Chance fracture) at L2. Which of the following associated injuries must be aggressively ruled out in this patient?

. Aortic transection
. Diaphragmatic rupture
. Hollow viscus intestinal injury
. Renal artery thrombosis
. Splenic laceration

Correct Answer & Explanation

. Hollow viscus intestinal injury

Explanation

A Chance fracture is a flexion-distraction injury of the spine, historically associated with lap-belt use in motor vehicle accidents. The fulcrum of flexion is located anterior to the vertebral body, resulting in failure of the posterior and middle columns in tension. Up to 40-50% of these patients have an associated intra-abdominal injury, most commonly involving hollow viscus organs (small bowel lacerations or perforations) due to the severe compression of the abdomen against the lap belt.

Question 3384

Topic: 6. Spine

In patients undergoing surgical decompression for Cervical Spondylotic Myelopathy (CSM), which of the following preoperative factors has been consistently proven in the literature to be the strongest predictor of postoperative neurological recovery and clinical outcome?

. Age of the patient at the time of surgery
. Presence of T2 hyperintensity on preoperative MRI
. Number of surgical levels decompressed
. Baseline severity of myelopathy (mJOA score) and duration of symptoms
. Choice of anterior versus posterior surgical approach

Correct Answer & Explanation

. Baseline severity of myelopathy (mJOA score) and duration of symptoms

Explanation

Multiple large prospective studies, including those by the AOSpine North America and International CSM studies, have shown that the strongest predictors of postoperative outcomes in CSM are the baseline severity of myelopathy (modified Japanese Orthopaedic Association - mJOA score) and the duration of symptoms prior to surgery. While T2 hyperintensity (and especially T1 hypointensity) and age have some prognostic value, baseline clinical severity and chronicity are the most robust predictors. Surgical approach does not significantly alter the ultimate neurological recovery if adequately decompressed.

Question 3385

Topic: 6. Spine

A 65-year-old male presents with bilateral leg pain and heaviness that worsens with walking and improves when he leans forward on a shopping cart. MRI shows severe L4-L5 central spinal stenosis. Which anatomic structure is the primary cause of dorsal compression in this condition?

. Herniated nucleus pulposus
. Hypertrophied ligamentum flavum
. Osteophytes from the vertebral body
. Ossification of the posterior longitudinal ligament
. Spondylolytic defect

Correct Answer & Explanation

. Hypertrophied ligamentum flavum

Explanation

Degenerative central spinal stenosis is classically caused by a combination of bulging intervertebral disc anteriorly, facet joint hypertrophy laterally, and a hypertrophied (and often buckled) ligamentum flavum posteriorly/dorsally. Thus, the ligamentum flavum causes the dorsal compression.

Question 3386

Topic: 6. Spine

A 72-year-old male with progressive clumsiness in his hands and a wide-based gait is diagnosed with cervical spondylotic myelopathy (Nurick grade 4). MRI demonstrates multi-level continuous compression from C3 to C6, predominantly due to ossification of the posterior longitudinal ligament (OPLL). Cervical lordosis is preserved. Which surgical approach is generally most appropriate?

. Anterior cervical discectomy and fusion (ACDF) C3-C6
. Anterior cervical corpectomy C4 and C5 with strut grafting
. Posterior cervical laminectomy and fusion (or laminoplasty)
. Multi-level cervical disc arthroplasty
. Stand-alone multi-level posterior foraminotomies

Correct Answer & Explanation

. Posterior cervical laminectomy and fusion (or laminoplasty)

Explanation

In patients with multi-level (3 or more) spinal cord compression primarily due to OPLL, especially when cervical lordosis is preserved, a posterior approach (laminectomy and fusion or laminoplasty) is preferred. Multi-level anterior corpectomies for continuous OPLL carry unacceptably high risks of dural tears, cerebrospinal fluid leaks, and construct failure.

Question 3387

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast complains of mechanical lower back pain and bilateral L5 radicular symptoms. Lateral lumbar radiographs demonstrate a Grade II forward slip of L5 on S1. What is the most likely pathological mechanism underlying this specific type of spondylolisthesis?

. Degeneration of the L5-S1 facet joints and intervertebral disc
. Congenital dysplasia of the superior sacral articular facets
. Fatigue stress fracture of the pars interarticularis
. Acute traumatic bilateral pedicle fractures
. Pathologic destruction of the pars by an underlying tumor

Correct Answer & Explanation

. Fatigue stress fracture of the pars interarticularis

Explanation

Isthmic spondylolisthesis is the most common type of spondylolisthesis in children and adolescents, particularly in athletes subjected to repetitive hyperextension forces (e.g., gymnastics, football linemen). It is caused by a fatigue stress fracture or elongation (spondylolysis) of the pars interarticularis, almost exclusively at the L5 level.

Question 3388

Topic: Cervical Spine

During the physical examination of a patient with suspected cervical spondylotic myelopathy, the examiner supports the patient's hand and firmly flicks the distal phalanx of the middle finger downward. A positive response is noted as reflex flexion of the interphalangeal joint of the thumb. What is the name of this clinical sign?

. Lhermitte's sign
. Wartenberg's sign
. Hoffmann's sign
. Spurling's sign
. Babinski reflex

Correct Answer & Explanation

. Hoffmann's sign

Explanation

Hoffmann's sign is an upper motor neuron sign elicited by flicking the distal phalanx of the middle finger, leading to reflex flexion of the thumb and/or index finger. It indicates cervical cord compression or other upper motor neuron pathology.

Question 3389

Topic: 6. Spine

A 55-year-old man undergoes a C3-C7 posterior cervical laminectomy and instrumented fusion for cervical myelopathy. On postoperative day 2, he develops profound new weakness in his right deltoid and biceps (muscle grade 2/5) but denies any new sensory changes, and his myelopathic symptoms in the lower extremities are improving. What is the most widely accepted primary pathophysiologic mechanism for this specific complication?

. Epidural hematoma causing cord compression
. Direct intraoperative nerve root transaction
. Anterior shift of the spinal cord causing vascular compromise
. Posterior drift of the spinal cord causing tethering of the nerve root
. Ischemic injury isolated to the anterior spinal artery

Correct Answer & Explanation

. Posterior drift of the spinal cord causing tethering of the nerve root

Explanation

The patient is experiencing a C5 nerve root palsy, a known complication occurring in roughly 5-10% of patients following cervical decompression (especially laminectomy). The most widely accepted mechanism is the posterior drift or 'shift' of the spinal cord following decompression, which tethers the C5 nerve root. The C5 root is particularly vulnerable due to its short, transverse course and the lack of redundant length compared to lower cervical roots. Most cases recover spontaneously over several months with observation and physical therapy.

Question 3390

Topic: 6. Spine

A 45-year-old male presents with chronic back pain and new-onset radicular symptoms in his right leg. Radiographs reveal an isthmic spondylolisthesis with a 25% slip of L5 on S1. If this patient has a single radiculopathy corresponding to the most commonly affected nerve root in this specific condition, which nerve root is involved?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. S3 nerve root

Correct Answer & Explanation

. L5 nerve root

Explanation

In isthmic spondylolisthesis at L5-S1, the defect is in the pars interarticularis (the isthmus). The slippage of L5 forward on S1 causes narrowing of the L5-S1 neural foramen. Additionally, hypertrophic fibrocartilaginous tissue at the pars defect further compromises the foramen, leading to compression of the exiting L5 nerve root. This contrasts with a central disc herniation at L5-S1, which would typically compress the traversing S1 nerve root.

Question 3391

Topic: 6. Spine

A 24-year-old male is brought to the emergency department after a high-speed motor vehicle collision where he was wearing a lap belt only. Radiographs of the spine reveal a Chance fracture of L2. Due to the mechanism of this specific spinal injury, the trauma team must maintain a high index of suspicion for which of the following associated injuries?

. Aortic tear
. Diaphragmatic rupture
. Hollow viscus intra-abdominal injury
. Renal laceration
. Tracheobronchial tear

Correct Answer & Explanation

. Hollow viscus intra-abdominal injury

Explanation

A Chance fracture is a flexion-distraction injury of the spine, classically associated with lap seatbelt use in motor vehicle collisions. The fulcrum of flexion is anterior to the spine (at the abdominal wall), causing severe distraction forces through the posterior and middle columns. This mechanism highly correlates with severe intra-abdominal injuries, particularly hollow viscus injuries (e.g., bowel perforations or mesenteric tears), which are found in up to 40-50% of patients with a Chance fracture.

Question 3392

Topic: 6. Spine

A 68-year-old male complains of bilateral leg pain and cramping that worsens after walking two blocks. Which of the following clinical findings most reliably differentiates neurogenic claudication (due to spinal stenosis) from vascular claudication?

. Pain relief occurs immediately upon standing still
. Pain is relieved by walking up an incline or leaning forward on a shopping cart
. Absent distal pedal pulses
. Loss of hair on the distal lower extremities
. Pain consistently starts in the calves and radiates proximally

Correct Answer & Explanation

. Pain is relieved by walking up an incline or leaning forward on a shopping cart

Explanation

Neurogenic claudication is exacerbated by lumbar extension (which decreases the cross-sectional area of the spinal canal) and relieved by lumbar flexion. Therefore, activities that promote lumbar flexion, such as walking uphill or leaning forward on a shopping cart (the 'shopping cart sign'), alleviate symptoms. Vascular claudication is workload-dependent and is relieved by simply standing still, regardless of posture.

Question 3393

Topic: 6. Spine

A 68-year-old man presents with bilateral leg heaviness, cramping, and pain that severely limits his walking distance. Which of the following historical features or clinical tests most reliably differentiates neurogenic claudication (due to lumbar spinal stenosis) from vascular claudication?

. Immediate pain relief simply by stopping walking and standing stationary
. Pain relief when leaning forward or riding a stationary bicycle
. Presence of severe pain at rest in the distal lower extremities
. Exacerbation of leg pain with lumbar flexion maneuvers
. Loss of protective sensation using a 10-g monofilament

Correct Answer & Explanation

. Pain relief when leaning forward or riding a stationary bicycle

Explanation

The bicycle test of van Gelderen is a classic method to differentiate neurogenic from vascular claudication. In neurogenic claudication, spinal flexion (such as leaning forward on a bike) opens the central canal and neural foramina, relieving ischemia to the nerve roots and preventing pain. In vascular claudication, the increased metabolic demand of the leg muscles during cycling will provoke pain regardless of the flexed posture.

Question 3394

Topic: 6. Spine

A 68-year-old male presents with progressive clumsiness in his hands and difficulty buttoning his shirts. Physical examination raises suspicion for cervical spondylotic myelopathy. The examiner tests for a Hoffmann sign. A positive response is indicated by which of the following movements when the nail of the patient\'s middle finger is briskly flicked downward?

. Extension of the thumb and index finger
. Flexion of the interphalangeal joint of the thumb and index finger
. Abduction of the little finger
. Rapid pronation of the forearm
. Isolated flexion of the middle finger

Correct Answer & Explanation

. Flexion of the interphalangeal joint of the thumb and index finger

Explanation

Hoffmann's sign is an indicator of upper motor neuron damage, often seen in cervical myelopathy. It is elicited by stabilizing the patient's middle finger and briskly flicking the distal phalanx downward. A positive test is the reflexive flexion of the interphalangeal joint of the thumb and/or index finger.

Question 3395

Topic: Thoracolumbar Spine & Deformity

A 34-year-old construction worker falls 10 feet, sustaining a T12 burst fracture. He is neurologically intact. CT and MRI scans reveal a burst morphology with 25% canal compromise and an intact posterior ligamentous complex (PLC). Using the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the most appropriate treatment recommendation?

. Score 2; Non-operative management
. Score 4; Operative management
. Score 5; Operative management
. Score 7; Operative management
. Score 2; Operative management

Correct Answer & Explanation

. Score 2; Non-operative management

Explanation

The TLICS system scores injuries based on three categories: Morphology, Neurologic Status, and PLC integrity. For this patient: Morphology is a burst fracture (2 points). Neurologic status is intact (0 points). PLC is intact (0 points). Total score = 2. A score of 3 or less dictates non-operative management. A score of 4 is equivocal, and 5 or more indicates surgery.

Question 3396

Topic: 6. Spine

A 45-year-old man presents with severe right anterior thigh pain and weakness. MRI reveals a far lateral (extraforaminal) disc herniation at the L3-L4 level on the right side. Which nerve root is most likely compressed, and what is the typical motor deficit?

. L3 nerve root; weakness in hip flexion and knee extension
. L4 nerve root; weakness in ankle dorsiflexion
. L3 nerve root; weakness in great toe extension
. L4 nerve root; weakness in knee extension and loss of patellar reflex
. L5 nerve root; weakness in hip abduction

Correct Answer & Explanation

. L3 nerve root; weakness in hip flexion and knee extension

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at that same level. Therefore, an L3-L4 far lateral disc compresses the L3 nerve root. The L3 nerve root innervates the iliopsoas and quadriceps, presenting with anterior thigh pain and weakness in hip flexion and knee extension. A paracentral herniation at L3-L4 would compress the traversing L4 nerve root.

Question 3397

Topic: Cervical Spine

A 70-year-old male sustains a Type II odontoid fracture after a ground-level fall. Which of the following radiographic findings is most strongly associated with a high risk of non-union if treated conservatively with a rigid cervical collar?

. Anterior displacement of 3 mm
. Fracture line extending into the vertebral body
. Posterior displacement of 6 mm
. An impacted fracture with 2 degrees of angulation
. Presence of an isolated, non-displaced C1 arch fracture

Correct Answer & Explanation

. Posterior displacement of 6 mm

Explanation

Type II odontoid fractures (fractures at the base of the dens) have a high rate of non-union due to tenuous blood supply. Risk factors for non-union include: age > 50 years, initial displacement > 5 mm (anterior or posterior), angulation > 10 degrees, and posterior displacement direction. Therefore, posterior displacement of 6 mm is a major risk factor for non-union, often warranting surgical stabilization.

Question 3398

Topic: 6. Spine

When planning corrective surgery for adult degenerative spinal deformity to optimize patient-reported outcomes and minimize the risk of adjacent segment breakdown, achieving appropriate sagittal balance is paramount. According to current biomechanical targets, the mismatch between Pelvic Incidence (PI) and Lumbar Lordosis (LL) should ideally be corrected to within:

. 0 degrees
. 10 degrees
. 20 degrees
. 30 degrees
. 40 degrees

Correct Answer & Explanation

. 10 degrees

Explanation

The widely accepted threshold for an optimal spinopelvic relationship in adult spinal deformity surgery is a Pelvic Incidence minus Lumbar Lordosis (PI - LL) mismatch of less than 10 degrees. This helps restore physiologic sagittal alignment and correlates with better clinical outcomes.

Question 3399

Topic: 6. Spine

A 68-year-old male presents with bilateral lower extremity pain and cramping associated with walking. To differentiate between neurogenic claudication (due to lumbar spinal stenosis) and vascular claudication (due to peripheral arterial disease), which of the following historical features is most specific for neurogenic claudication?

. Relief of symptoms when stopping and standing completely upright
. Pain exacerbation that occurs promptly when riding a stationary bicycle
. Relief of symptoms when continuing to walk while leaning forward over a shopping cart
. Diminished posterior tibial and dorsalis pedis pulses
. Symptoms consistently begin distally in the calves and radiate proximally

Correct Answer & Explanation

. Relief of symptoms when continuing to walk while leaning forward over a shopping cart

Explanation

The "shopping cart sign"—relief of claudication symptoms while walking in a flexed posture—is highly specific for neurogenic claudication. Flexion increases the cross-sectional area of the spinal canal, relieving nerve root compression. Vascular claudication is worsened by any leg exercise (including stationary bicycling) due to metabolic demand and is relieved simply by standing rest, unaffected by posture.

Question 3400

Topic: 6. Spine

A 35-year-old man presents after a motor vehicle collision with severe neck pain. Radiographs reveal a traumatic spondylolisthesis of the axis (Hangman's fracture) with 15 degrees of angulation and 2 mm of anterior translation. The fracture line is oblique from anterior-inferior to posterior-superior. Which of the following is true regarding the management of this specific fracture pattern (Effendi/Levine Type IIA)?

. Immediate longitudinal cervical traction is the first line of treatment
. It is caused primarily by a hyperextension-axial loading mechanism
. Cervical traction is strictly contraindicated due to the risk of over-distraction
. Treatment primarily consists of a soft cervical collar for 6 weeks
. Posterior C1-C2 fusion is universally required due to high rates of nonunion

Correct Answer & Explanation

. Cervical traction is strictly contraindicated due to the risk of over-distraction

Explanation

This is a Type IIA Hangman's fracture, characterized by severe angulation with minimal translation. The mechanism is flexion-distraction, which disrupts the C2-C3 intervertebral disc and posterior longitudinal ligament, while the anterior longitudinal ligament remains intact. Because the posterior restraints are completely torn, applying cervical traction is strictly contraindicated as it can cause massive over-distraction and subsequent severe neurologic injury. Reduction is achieved with gentle extension and axial compression, followed by halo immobilization.

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