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6. Spine MCQs

Practice Set 263 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 5241

Topic: 6. Spine

A 45-year-old man presents with severe lower back pain, bilateral sciatica, and perineal numbness. Which of the following objective findings is most sensitive for diagnosing early urinary dysfunction associated with cauda equina syndrome?

. Inability to initiate a urine stream
. Decreased anal sphincter tone on digital exam
. Post-void residual volume greater than 200 mL
. Absence of the bulbocavernosus reflex
. Positive crossed straight leg raise test

Correct Answer & Explanation

. Post-void residual volume greater than 200 mL

Explanation

A post-void residual volume greater than 100-200 mL measured via bladder ultrasound or catheterization is highly sensitive for the urinary retention that classically characterizes early cauda equina syndrome.

Question 5242

Topic: 6. Spine

A 50-year-old woman presents with progressive myelopathy due to a large, calcified, central disc herniation at T8-T9. What is the most appropriate surgical approach for decompression?

. Standard posterior laminectomy
. Anterior transthoracic discectomy and fusion
. Posterior laminoplasty
. Minimally invasive posterior microdiscectomy
. Bilateral foraminotomies

Correct Answer & Explanation

. Anterior transthoracic discectomy and fusion

Explanation

Central, calcified thoracic disc herniations should be approached anteriorly or anterolaterally. A standard posterior laminectomy is contraindicated due to the high risk of catastrophic spinal cord injury from manipulating the cord.

Question 5243

Topic: 6. Spine

A 35-year-old man is involved in a motor vehicle accident and sustains a traumatic spondylolisthesis of C2 (Hangman's fracture). Imaging shows a fracture through the pars interarticularis with 4 mm of translation. This injury is best described by which of the following mechanisms?

. Hyperflexion and axial loading
. Hyperextension and axial loading
. Lateral bending and rotation
. Hyperextension and distraction
. Hyperflexion and distraction

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A Hangman's fracture classically results from a hyperextension and axial loading mechanism. This is commonly seen in motor vehicle collisions when the unrestrained head strikes the dashboard.

Question 5244

Topic: 6. Spine

A 25-year-old man wearing a lap seatbelt without a shoulder harness is involved in a high-speed collision. He sustains a flexion-distraction injury of the L1 vertebra (Chance fracture). What concomitant injury must be aggressively evaluated?

. Diaphragmatic rupture
. Ascending aortic dissection
. Intra-abdominal hollow viscus injury
. Pelvic ring disruption
. Renal artery thrombosis

Correct Answer & Explanation

. Intra-abdominal hollow viscus injury

Explanation

Chance fractures (flexion-distraction injuries) resulting from a lap belt mechanism have a high association (up to 50%) with intra-abdominal injuries, particularly to hollow viscous organs and the mesentery.

Question 5245

Topic: 6. Spine
A 65-year-old Asian male presents with progressive hand clumsiness and gait imbalance. Imaging shows multilevel Ossification of the Posterior Longitudinal Ligament (OPLL) with a K-line negative cervical spine. Which of the following procedures is generally considered CONTRAINDICATED as a standalone procedure for this patient?
. Anterior cervical corpectomy and fusion
. Cervical laminoplasty
. Posterior cervical laminectomy and instrumented fusion
. Combined anterior-posterior decompression and fusion
. Anterior cervical discectomy and fusion

Correct Answer & Explanation

. Cervical laminoplasty

Explanation

A K-line negative OPLL indicates significant kyphosis or massive anterior ossification preventing the spinal cord from shifting posteriorly post-decompression. Therefore, a standalone cervical laminoplasty will fail to decompress the cord and is contraindicated.

Question 5246

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman undergoes corrective surgery for flatback syndrome. To achieve optimal sagittal balance and minimize compensatory mechanisms, her postoperative lumbar lordosis (LL) should be matched to within 10 degrees of which of the following spinopelvic parameters?

. Pelvic tilt (PT)
. Sacral slope (SS)
. Pelvic incidence (PI)
. Thoracic kyphosis (TK)
. Sagittal vertical axis (SVA)

Correct Answer & Explanation

. Pelvic incidence (PI)

Explanation

To maintain proper sagittal balance, postoperative lumbar lordosis (LL) should match the patient's fixed pelvic incidence (PI) within 10 degrees (PI = LL +/- 10 degrees). This minimizes compensatory mechanisms and improves clinical outcomes.

Question 5247

Topic: 6. Spine

Following a C3-C7 posterior cervical laminectomy and fusion for severe cervical spondylotic myelopathy, a patient develops isolated, unilateral deltoid and biceps weakness on postoperative day 3. Sensation remains intact. What is the most likely etiology of this new deficit?

. Epidural hematoma
. Iatrogenic spinal cord injury
. C5 nerve root tethering
. Graft dislodgement
. Vertebral artery injury

Correct Answer & Explanation

. C5 nerve root tethering

Explanation

C5 palsy is a known complication of extensive cervical decompression, resulting from the posterior shift of the spinal cord and subsequent tethering of the short C5 nerve root. It typically presents 2-5 days postoperatively with isolated deltoid and biceps weakness.

Question 5248

Topic: Cervical Spine

An 82-year-old man sustains a Type II odontoid fracture after a ground-level fall. He has severe medical comorbidities, including heart failure and severe chronic obstructive pulmonary disease. What is the most appropriate initial management strategy?

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

Correct Answer & Explanation

. Rigid cervical collar

Explanation

Recent literature demonstrates that rigid cervical collars are an acceptable, non-inferior treatment for Type II odontoid fractures in the elderly, avoiding high surgical morbidity. Halo vest immobilization is contraindicated in this demographic due to unacceptably high mortality rates.

Question 5249

Topic: 6. Spine

A 45-year-old man presents with severe right anterior thigh pain and new-onset weakness in knee extension. MRI reveals a far lateral (extraforaminal) disc herniation at the L3-L4 level. Which nerve root is most likely compressed by this lesion?

. L2
. L3
. L4
. L5
. S1

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at that respective level. Therefore, an L3-L4 far lateral disc herniation will directly compress the exiting L3 nerve root.

Question 5250

Topic: 6. Spine

A 65-year-old male presents with neurogenic claudication. Radiographs demonstrate a degenerative Grade 1 spondylolisthesis at L4-L5 with 4 mm of dynamic translation on flexion-extension views. He has failed 6 months of non-operative management. What is the most appropriate surgical treatment?

. L4-L5 Laminectomy alone
. L4-L5 Laminectomy with instrumented fusion
. X-ray guided epidural steroid injection
. Interspinous process spacer
. Anterior lumbar interbody fusion alone

Correct Answer & Explanation

. L4-L5 Laminectomy with instrumented fusion

Explanation

For patients with degenerative spondylolisthesis and objective dynamic instability, decompression and instrumented fusion is the gold standard. Laminectomy alone in the presence of dynamic instability risks progressive slip and recurrent symptoms.

Question 5251

Topic: Cervical Spine

A 24-year-old male is involved in a motor vehicle collision.

CT of the cervical spine shows a Type II odontoid fracture with 7 mm of posterior displacement. The patient is neurologically intact. What is the most appropriate definitive management?

. Rigid cervical collar for 12 weeks
. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 instrumentation and fusion
. Transoral odontoidectomy

Correct Answer & Explanation

. Posterior C1-C2 instrumentation and fusion

Explanation

Type II odontoid fractures with significant displacement (>5 mm) have a high nonunion rate with conservative management. Posterior C1-C2 fusion is indicated because posterior displacement is a relative contraindication to anterior screw placement.

Question 5252

Topic: 6. Spine

A 45-year-old female presents with progressive clumsiness in her hands and wide-based gait. Exam reveals positive Hoffmann's signs bilaterally. MRI reveals severe cervical cord compression at C4-C6 with T2 signal changes in the spinal cord. Upright radiographs demonstrate a 15-degree fixed cervical kyphosis. What is the most appropriate surgical approach?

. Anterior cervical decompression and fusion (ACDF)
. Cervical laminectomy without fusion
. Posterior cervical laminoplasty
. Posterior cervical laminectomy and fusion
. Cervical disc arthroplasty

Correct Answer & Explanation

. Anterior cervical decompression and fusion (ACDF)

Explanation

In the setting of cervical myelopathy with a fixed kyphotic deformity, an anterior approach (ACDF or corpectomy) is required to decompress the cord draped over anterior pathology and restore lordosis. Posterior decompression alone fails to adequately decompress the spinal cord in fixed kyphosis.

Question 5253

Topic: 6. Spine

A 68-year-old man presents with bilateral leg pain and fatigue that worsens with walking. Which of the following historical findings is most specific for differentiating neurogenic claudication from vascular claudication?

. Pain relief upon standing stationary
. Pain relief while riding a stationary bicycle
. Absence of pedal pulses
. Worsening pain with lumbar flexion
. Pain radiating proximal to distal

Correct Answer & Explanation

. Pain relief while riding a stationary bicycle

Explanation

Neurogenic claudication is relieved by lumbar flexion, such as when riding a stationary bicycle or leaning on a shopping cart. Vascular claudication is worsened by any lower extremity exertion regardless of lumbar posture and is relieved by standing stationary.

Question 5254

Topic: Cervical Spine

A 55-year-old woman with a 20-year history of rheumatoid arthritis presents with progressive hand clumsiness and hyperreflexia. Radiographs reveal atlantoaxial instability. Which of the following radiographic measurements is the strongest predictor of postoperative neurologic recovery?

. Anterior atlantodental interval (ADI) greater than 9 mm
. Posterior atlantodental interval (PADI) less than 14 mm
. Cervical lordosis angle
. Subaxial subluxation of 3 mm
. Ranawat line measurement of 15 mm

Correct Answer & Explanation

. Posterior atlantodental interval (PADI) less than 14 mm

Explanation

The posterior atlantodental interval (PADI) represents the true space available for the spinal cord. A PADI of less than 14 mm is an absolute indication for surgery and strongly correlates with an inability to achieve neurologic recovery.

Question 5255

Topic: 6. Spine



A 45-year-old man presents with severe left anterior thigh pain and trace quadriceps weakness. An MRI demonstrates a far lateral (extraforaminal) disc herniation at the L3-L4 level. Which nerve root is most likely compressed?

. L2
. L3
. L4
. L5
. S1

Correct Answer & Explanation

. L3

Explanation

A far lateral (extraforaminal) disc herniation impinges the exiting nerve root at the same level. Therefore, an L3-L4 far lateral disc herniation will compress the exiting L3 nerve root, causing anterior thigh symptoms.

Question 5256

Topic: 6. Spine



A 62-year-old man with ankylosing spondylitis presents to the ER after a ground-level fall. He has severe neck pain but intact neurology. A CT scan reveals a transverse fracture through the C5-C6 disc space. He is admitted and placed in a hard collar. Several hours later, he develops progressive bilateral upper and lower extremity weakness. What is the most likely cause?

. Epidural abscess
. Spinal epidural hematoma
. Vertebral artery dissection
. Syringomyelia
. Central cord syndrome from hyperextension

Correct Answer & Explanation

. Spinal epidural hematoma

Explanation

Patients with ankylosing spondylitis are at extremely high risk for highly unstable, highly displaced fractures and subsequent spinal epidural hematomas. Sudden neurologic deterioration after an AS spine fracture is most commonly due to epidural hematoma, requiring urgent MRI and decompression.

Question 5257

Topic: 6. Spine

During a posterior spinal fusion for scoliosis, neuromonitoring demonstrates a sudden, sustained loss of motor evoked potentials (MEPs) in both lower extremities, while somatosensory evoked potentials (SSEPs) remain intact. What is the most likely pathophysiologic cause?

. Ischemia to the dorsal columns
. Ischemia to the anterior spinal artery
. Direct mechanical injury to the entire cord
. Inadequate anesthetic depth
. Hypothermia

Correct Answer & Explanation

. Ischemia to the anterior spinal artery

Explanation

MEPs monitor the anterior and lateral corticospinal tracts, supplied by the anterior spinal artery. Loss of MEPs with preserved SSEPs indicates an anterior cord syndrome, likely due to anterior spinal artery ischemia or injury.

Question 5258

Topic: 6. Spine

A 52-year-old man presents with right arm pain and numbness radiating to his thumb and index finger. Examination reveals weakness in wrist extension and a diminished brachioradialis reflex. Which cervical disc level is most likely affected?

. C3-C4
. C4-C5
. C5-C6
. C6-C7
. C7-T1

Correct Answer & Explanation

. C5-C6

Explanation

The patient exhibits classic signs of a C6 radiculopathy (weak wrist extension, numbness in the thumb/index finger, and diminished brachioradialis reflex). This is most commonly caused by a herniated disc at the C5-C6 level.

Question 5259

Topic: 6. Spine

A 16-year-old boy presents with progressive mid-back pain. Lateral radiographs show anterior wedging of 7 degrees in four consecutive thoracic vertebrae and irregular vertebral endplates with Schmorl's nodes. Which of the following is the most likely diagnosis?

. Adolescent idiopathic scoliosis
. Scheuermann's kyphosis
. Postural kyphosis
. Ankylosing spondylitis
. Eosinophilic granuloma

Correct Answer & Explanation

. Scheuermann's kyphosis

Explanation

Scheuermann's kyphosis is defined radiographically by anterior wedging of greater than 5 degrees in at least three consecutive vertebrae. Associated findings include Schmorl's nodes, endplate irregularities, and a rigid kyphotic deformity.

Question 5260

Topic: 6. Spine

A 68-year-old man with a history of diffuse idiopathic skeletal hyperostosis (DISH) presents with progressive solid food dysphagia. What is the most likely pathophysiologic mechanism for his symptom?

. Esophageal dysmotility from autonomic neuropathy
. Direct mechanical compression by anterior cervical osteophytes
. Cricopharyngeal muscle spasm
. Ossification of the posterior longitudinal ligament
. Zenker's diverticulum formation

Correct Answer & Explanation

. Direct mechanical compression by anterior cervical osteophytes

Explanation

DISH often involves prominent ossification of the anterior longitudinal ligament (ALL) in the cervical spine. These large anterior osteophytes can cause direct mechanical compression of the esophagus, leading to dysphagia.

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