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6. Spine MCQs

Practice Set 267 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 5321

Topic: Thoracolumbar Spine & Deformity

A 14-year-old gymnast has persistent back pain and radicular leg pain due to a Grade II L5-S1 isthmic spondylolisthesis. She has failed 6 months of conservative management including bracing and physical therapy. What is the most appropriate surgical intervention?

. Direct pars repair with wiring
. L5-S1 anterior lumbar interbody fusion only
. L5-S1 posterior instrumented fusion
. L5 laminectomy without fusion
. Continuation of non-operative observation

Correct Answer & Explanation

. L5-S1 posterior instrumented fusion

Explanation

In adolescents with a symptomatic Grade II isthmic spondylolisthesis that fails conservative treatment, posterior or transforaminal instrumented fusion is the standard of care. Pars repair is generally reserved for Grade 0 or I slips without disc degeneration.

Question 5322

Topic: 6. Spine

A 65-year-old man undergoes a C3-C6 laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 1, he develops isolated weakness in his right deltoid and biceps (2/5 strength), with normal strength elsewhere and no sensory deficits. What is the most appropriate initial management?

. Immediate return to the operating room for C4-C5 foraminotomy
. High-dose intravenous methylprednisolone
. Observation and physical therapy
. Stat MRI of the cervical spine
. CT myelogram

Correct Answer & Explanation

. Observation and physical therapy

Explanation

C5 palsy is a known complication of cervical decompression, particularly laminectomy and fusion, due to posterior spinal cord shift and nerve root tethering. It is usually motor-dominant and self-limiting, with the vast majority of patients recovering full function through observation and physical therapy.

Question 5323

Topic: 6. Spine

A 68-year-old woman presents with severe low back pain and difficulty standing upright. Standing lateral radiographs reveal a pelvic incidence (PI) of 60 degrees and a lumbar lordosis (LL) of 30 degrees. To achieve optimal sagittal balance, what is the surgical target for her lumbar lordosis?

. 20 degrees
. 30 degrees
. 40 degrees
. 50 degrees
. 70 degrees

Correct Answer & Explanation

. 50 degrees

Explanation

In adult spinal deformity surgery, the primary goal is to correct the PI-LL mismatch to within 10 degrees (LL = PI +/- 10 degrees). For a PI of 60 degrees, a lumbar lordosis of approximately 50 to 60 degrees should be targeted to restore sagittal balance.

Question 5324

Topic: 6. Spine

A 55-year-old man with long-standing ankylosing spondylitis presents to the emergency department with neck pain after a low-speed motor vehicle collision. Neurologic examination is normal. Standard AP and lateral cervical radiographs are read as negative. What is the most appropriate next step in management?

. Discharge with a soft cervical collar and outpatient follow-up
. Flexion-extension cervical radiographs
. CT scan of the entire cervical spine
. Prescribe NSAIDs and discharge
. MRI of the cervical spine without contrast

Correct Answer & Explanation

. CT scan of the entire cervical spine

Explanation

Patients with ankylosing spondylitis are at an extremely high risk for unstable extension-distraction fractures even following minor trauma. Due to altered osseous anatomy and generalized osteopenia, standard radiographs are inadequate, making a CT scan of the entire cervical spine mandatory to rule out occult fractures.

Question 5325

Topic: Thoracolumbar Spine & Deformity

A 30-year-old man falls from a 10-foot ladder. CT reveals an L1 burst fracture with 40% canal compromise. MRI shows an intact posterior ligamentous complex (PLC). Neurologic exam is completely normal. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended treatment?

. TLICS 2; nonoperative management
. TLICS 4; nonoperative management
. TLICS 4; operative management
. TLICS 5; operative management
. TLICS 7; operative management

Correct Answer & Explanation

. TLICS 2; nonoperative management

Explanation

The TLICS score for this patient is 2: 2 points for burst fracture morphology, 0 points for an intact PLC, and 0 points for normal neurologic status. A total score of 3 or less indicates nonoperative management, typically with a rigid orthosis or early mobilization.

Question 5326

Topic: 6. Spine

A 50-year-old diabetic man presents with 3 days of worsening neck pain, fever, and new-onset clumsiness in his hands. Exam reveals weakness in bilateral hand intrinsics and hyperreflexia in the lower extremities. MRI reveals a ventral cervical epidural abscess extending from C3 to C6. What is the most appropriate definitive management?

. CT-guided needle aspiration and IV antibiotics
. IV antibiotics and rigid cervical collar
. Posterior cervical laminectomy and debridement
. Anterior cervical corpectomy, debridement, and fusion
. Posterior cervical laminoplasty

Correct Answer & Explanation

. Anterior cervical corpectomy, debridement, and fusion

Explanation

A ventral cervical epidural abscess causing acute myelopathy requires urgent surgical decompression. An anterior approach (corpectomy, debridement, and fusion) allows direct visualization and complete evacuation of the ventral pathology without manipulating the already compromised spinal cord.

Question 5327

Topic: 6. Spine
A 72-year-old man with known severe cervical stenosis falls forward and strikes his chin. He presents with profound weakness in his upper extremities (1/5) but preserved strength in his lower extremities (4/5). MRI shows cord signal change at C4-C5 without fracture or instability. If surgery is planned, what is the currently recommended timing for decompression?
. Emergent decompression within 4 hours
. Early decompression within 24 hours
. Delayed decompression after 1 week to allow edema to subside
. Delayed decompression after 6 weeks of rehabilitation
. No surgery is indicated for central cord syndrome

Correct Answer & Explanation

. Early decompression within 24 hours

Explanation

Acute traumatic central cord syndrome is increasingly treated with early surgical decompression. Recent evidence, such as the STASCIS trial, supports early intervention (within 24 hours) as it correlates with significantly better long-term neurologic recovery compared to delayed surgery.

Question 5328

Topic: 6. Spine

A 14-year-old girl is undergoing posterior spinal fusion for a Lenke 1A adolescent idiopathic scoliosis. Her stable vertebra (SV) is L1, and the end vertebra (EV) is T12. How should the Lowest Instrumented Vertebra (LIV) be selected to minimize the risk of distal adding-on?

. Stop at the end vertebra (T12) regardless of rotation
. Stop at the neutral vertebra even if it is above the end vertebra
. Stop at the stable vertebra (L1) or one level above (T12) if it is neutral
. Always fuse to L3 to prevent lumbar curve progression
. Fuse to the sacrum to ensure perfect coronal balance

Correct Answer & Explanation

. Stop at the stable vertebra (L1) or one level above (T12) if it is neutral

Explanation

To prevent distal "adding-on" in Lenke 1A curves, the lowest instrumented vertebra (LIV) is typically chosen as the stable vertebra, or the end vertebra if it also happens to be the neutral vertebra. Stopping short of the neutral or stable vertebra significantly increases the risk of adding-on.

Question 5329

Topic: 6. Spine

A 42-year-old man presents with acute bilateral sciatica, saddle anesthesia, and urinary retention (post-void residual of 600 mL) starting 12 hours ago. MRI shows a massive L4-L5 disc herniation compressing the thecal sac. What is the most critical prognostic factor for the return of his bowel and bladder function following emergent decompression?

. The degree of canal stenosis measured on MRI
. The patient's age
. The presence of bilateral versus unilateral sciatica
. The duration of symptoms prior to surgical decompression
. The type of surgical approach used (laminectomy vs microdiscectomy)

Correct Answer & Explanation

. The duration of symptoms prior to surgical decompression

Explanation

The single most important prognostic factor for neurologic recovery, particularly regarding bowel and bladder function, in cauda equina syndrome is the time elapsed from symptom onset to surgical decompression. Surgery should ideally be performed within 24 to 48 hours.

Question 5330

Topic: 6. Spine

A 65-year-old woman presents with neurogenic claudication and low back pain. Radiographs reveal a grade I degenerative spondylolisthesis at L4-L5 that is mobile on flexion-extension views. MRI shows severe central canal stenosis. According to the SLIP trial, which treatment provides the best long-term clinical outcome?

. Laminectomy alone
. Physical therapy and epidural steroid injections
. Laminectomy with posterior instrumented fusion
. Interspinous process spacer
. Anterior lumbar interbody fusion without posterior fixation

Correct Answer & Explanation

. Laminectomy with posterior instrumented fusion

Explanation

The SLIP trial demonstrated that for patients with lumbar spinal stenosis and degenerative spondylolisthesis, decompression with instrumented fusion provides superior clinical outcomes compared to laminectomy alone. Fusion prevents progressive postoperative instability and recurrent symptoms.

Question 5331

Topic: Cervical Spine

A healthy, active 75-year-old man falls and sustains a Type II odontoid fracture with 3 mm of displacement. He is neurologically intact. What is the most appropriate management that provides the highest union rate and lowest morbidity?

. Halo vest immobilization
. Rigid cervical collar for 12 weeks
. Anterior odontoid screw fixation
. Posterior C1-C2 fusion
. Anterior transoral excision of the odontoid

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

In active elderly patients, Type II odontoid fractures have a high nonunion rate with conservative care, and halo vest immobilization is associated with high morbidity and mortality. Posterior C1-C2 fusion provides the highest union rate and functional outcome in this demographic.

Question 5332

Topic: 6. Spine

A 55-year-old Asian man presents with progressive cervical myelopathy. Lateral radiographs and MRI reveal continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. The cervical spine maintains normal lordosis, and the K-line is positive. Which of the following surgical interventions is most appropriate?

. Anterior cervical corpectomy and fusion
. Posterior cervical laminoplasty
. Laminectomy without fusion
. Anterior cervical discectomy and fusion
. Posterior C1-C7 instrumented fusion

Correct Answer & Explanation

. Posterior cervical laminoplasty

Explanation

Posterior cervical laminoplasty is ideal for multilevel OPLL when cervical lordosis is preserved and the K-line is positive (the OPLL does not cross the line connecting the midpoints of the spinal canal at C2 and C7). Anterior approaches carry a higher risk of dural tears and complications in OPLL, though they are indicated if the spine is kyphotic.

Question 5333

Topic: 6. Spine

A 62-year-old woman with L4-L5 degenerative spondylolisthesis and neurogenic claudication elects to undergo surgical intervention after failing conservative management. Which of the following pre-operative MRI findings is most predictive of microinstability and would strongly necessitate an arthrodesis in addition to decompression?

. Modic Type 1 changes at L4-L5
. Ligamentum flavum hypertrophy > 4 mm
. Bilateral facet joint effusions > 1.5 mm
. Disc desiccation at L3-L4
. Multilevel lumbar central stenosis

Correct Answer & Explanation

. Bilateral facet joint effusions > 1.5 mm

Explanation

A facet joint effusion greater than 1.5 mm on T2-weighted axial MRI is highly predictive of microinstability in degenerative spondylolisthesis. Decompression alone in the presence of this finding has a high failure rate, making concomitant arthrodesis the recommended treatment.

Question 5334

Topic: 6. Spine

A 22-year-old man sustains a C4 complete spinal cord injury in a diving accident. In the trauma bay, his blood pressure is 80/50 mm Hg, heart rate is 48 bpm, and his extremities are warm and well-perfused. Which of the following best explains his hemodynamic instability?

. Occult retroperitoneal hemorrhage
. Loss of sympathetic vascular tone
. Cardiac tamponade
. Tension pneumothorax
. Adrenal insufficiency

Correct Answer & Explanation

. Loss of sympathetic vascular tone

Explanation

The patient is experiencing neurogenic shock, characterized by hypotension, bradycardia, and warm extremities. This results from the disruption of descending sympathetic pathways in the cervical cord, leaving vagal parasympathetic tone unopposed.

Question 5335

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman is being evaluated for progressive sagittal imbalance and severe flatback syndrome following a previous L3-S1 fusion. Radiographs reveal a pelvic incidence (PI) of 65 degrees and a current lumbar lordosis (LL) of 20 degrees. To optimize her postoperative clinical outcomes, her revision surgery should aim to restore her lumbar lordosis to approximately what value?

. 20 degrees
. 35 degrees
. 45 degrees
. 65 degrees
. 85 degrees

Correct Answer & Explanation

. 65 degrees

Explanation

For optimal sagittal balance, the lumbar lordosis (LL) should be matched to within 10 degrees of the pelvic incidence (PI). Therefore, a patient with a PI of 65 degrees should have a surgical target LL of approximately 55 to 65 degrees.

Question 5336

Topic: 6. Spine

A 60-year-old man undergoes a C3-C6 posterior laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day one, he develops new, isolated right-sided deltoid and biceps weakness (strength 2/5). His sensory exam and lower extremity motor exams are normal. An urgent MRI shows adequate cord decompression without hematoma. What is the most appropriate next step in management?

. Urgent return to the operating room for C4-C5 foraminotomies
. Intravenous administration of hypertonic saline
. Exploration of the brachial plexus
. Observation and physical therapy
. Placement of a lumbar drain

Correct Answer & Explanation

. Observation and physical therapy

Explanation

Isolated C5 palsy is a known complication following cervical decompression, likely due to posterior cord shift and tethering of the C5 nerve root. In the absence of a compressive hematoma or hardware misplacement, most cases recover spontaneously with conservative management and physical therapy.

Question 5337

Topic: 6. Spine

A 45-year-old intravenous drug user presents with 2 weeks of worsening back pain, low-grade fevers, and acute onset of bilateral lower extremity weakness over the last 12 hours (ASIA C). MRI reveals a large ventral epidural abscess spanning L2 to L5. What is the most appropriate management?

. Intravenous antibiotics alone for 6 weeks
. CT-guided aspiration followed by intravenous antibiotics
. Emergent open surgical decompression and debridement
. Placement of a percutaneous epidural drain
. Administration of high-dose methylprednisolone followed by serial MRI

Correct Answer & Explanation

. Emergent open surgical decompression and debridement

Explanation

Spinal epidural abscess presenting with an acute, progressive neurologic deficit is an absolute surgical emergency. Emergent open surgical decompression and debridement, followed by culture-directed IV antibiotics, is required to prevent irreversible neurologic injury.

Question 5338

Topic: Cervical Spine

A 75-year-old male sustains a Type II odontoid fracture with 3 mm of posterior displacement following a low-energy fall. He is neurologically intact. Which of the following is the most appropriate initial management?

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

Correct Answer & Explanation

. Rigid cervical collar

Explanation

In elderly patients with Type II odontoid fractures, halo vest immobilization has an unacceptably high morbidity and mortality rate. A rigid cervical collar is generally the preferred initial management for minimally displaced fractures in this population.

Question 5339

Topic: Cervical Spine

During an anterior cervical discectomy and fusion (ACDF) at C6-C7, the surgeon uses electrocautery near the lateral border of the longus colli muscle. Postoperatively, the patient develops ipsilateral ptosis and miosis. Injury to which of the following structures is most likely responsible?

. Recurrent laryngeal nerve
. Superior laryngeal nerve
. Sympathetic trunk
. Phrenic nerve
. Vagus nerve

Correct Answer & Explanation

. Sympathetic trunk

Explanation

The sympathetic trunk runs along the lateral border of the longus colli muscle. Injury to this structure during lateral dissection or retraction results in Horner's syndrome, characterized by ipsilateral ptosis, miosis, and anhidrosis.

Question 5340

Topic: 6. Spine

A 68-year-old male with a long-standing history of ankylosing spondylitis presents to the emergency department with severe neck pain after a minor fall. Plain radiographs of the cervical spine are unremarkable, and he is neurologically intact. What is the most appropriate next step in management?

. Discharge with NSAIDs and a soft collar
. Flexion-extension radiographs of the cervical spine
. CT or MRI of the cervical spine
. Immediate rigid halo vest placement
. Reassurance and outpatient physical therapy

Correct Answer & Explanation

. CT or MRI of the cervical spine

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable, occult spinal fractures even after minor trauma. If plain radiographs are negative, advanced imaging like CT or MRI is mandatory to rule out a fracture or epidural hematoma.

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