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6. Spine MCQs

Practice Set 234 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 4661

Topic: Thoracolumbar Spine & Deformity

A 25-year-old man falls from a roof and sustains an L1 burst fracture. He is neurologically intact. CT scan shows 30% canal compromise and kyphosis of 15 degrees. MRI confirms an intact posterior ligamentous complex (PLC). What is the most appropriate management?

. Thoracolumbosacral orthosis (TLSO) bracing
. Short-segment posterior spinal fusion
. Long-segment posterior spinal fusion
. Anterior corpectomy and fusion
. Percutaneous pedicle screw fixation without fusion

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing

Explanation

Thoracolumbar burst fractures in neurologically intact patients with an intact posterior ligamentous complex (TLICS score < 4) can be treated successfully with a rigid brace (TLSO). Surgery is not indicated for stable burst fractures without neurologic deficit.

Question 4662

Topic: 6. Spine

A 55-year-old man with long-standing ankylosing spondylitis presents to the emergency department after a minor ground-level fall, complaining of severe, new-onset neck pain. Initial plain radiographs of the cervical spine are interpreted as normal. His neurologic exam is intact. What is the most appropriate next step?

. Discharge with NSAIDs and a soft collar
. Obtain dynamic flexion-extension radiographs
. Perform a CT scan of the entire cervical spine
. Reassure the patient and initiate early physical therapy
. Administer high-dose intravenous corticosteroids

Correct Answer & Explanation

. Discharge with NSAIDs and a soft collar

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable, occult spinal fractures even after minor trauma. If plain films are negative or inadequately visualize the cervicothoracic junction, a CT scan is mandatory to rule out a fracture.

Question 4663

Topic: 6. Spine

A 65-year-old woman presents with severe neurogenic claudication and lower back pain. Imaging reveals a Grade I degenerative spondylolisthesis at L4-L5. She has failed 6 months of conservative management including physical therapy and epidural steroid injections. What is the most appropriate surgical treatment?

. L4-L5 laminectomy alone
. L4-L5 laminectomy and instrumented posterolateral fusion
. Anterior lumbar interbody fusion (ALIF) alone
. Interspinous process spacer placement
. L4-L5 disc arthroplasty

Correct Answer & Explanation

. L4-L5 laminectomy alone

Explanation

For symptomatic degenerative spondylolisthesis failing conservative treatment, surgical decompression combined with instrumented posterolateral fusion provides better long-term clinical outcomes than decompression alone, as it prevents progressive instability.

Question 4664

Topic: 6. Spine

A 70-year-old man presents with progressive hand clumsiness, frequent falls, and a positive Hoffman's sign. MRI shows severe cervical stenosis at C3-C6 with cord signal changes. Radiographs demonstrate a fixed cervical kyphosis of 15 degrees. Which surgical approach is most appropriate?

. Cervical laminectomy without fusion
. Cervical laminoplasty
. Anterior cervical decompression and fusion
. Stand-alone cervical disc replacement
. Posterior cervical foraminotomy

Correct Answer & Explanation

. Cervical laminectomy without fusion

Explanation

In a patient with cervical spondylotic myelopathy and a fixed kyphotic deformity, posterior-only decompression (like laminectomy or laminoplasty) is contraindicated as the spinal cord will not drift back. An anterior approach allows for direct decompression and correction of kyphosis.

Question 4665

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast complains of localized low back pain exacerbated by extension activities. Oblique lumbar radiographs demonstrate a "Scotty dog with a collar" sign. What is the precise anatomical location of the defect indicated by the "collar"?

. Pars interarticularis
. Pedicle
. Lamina
. Transverse process
. Spinous process

Correct Answer & Explanation

. Pars interarticularis

Explanation

The "collar" on the Scotty dog sign seen on oblique lumbar radiographs represents a defect or fracture in the pars interarticularis, which is the pathognomonic hallmark of spondylolysis.

Question 4666

Topic: 6. Spine

A 45-year-old male presents with severe low back pain, bilateral sciatica, saddle anesthesia, and acute urinary retention. A post-void bladder ultrasound reveals a residual volume of 400 mL. What is the most critical next step in management?

. Routine MRI of the lumbar spine within 48 hours
. Immediate administration of high-dose methylprednisolone
. Urgent MRI of the lumbar spine followed by surgical decompression
. Diagnostic lumbar puncture
. Urodynamic studies to confirm detrusor failure

Correct Answer & Explanation

. Routine MRI of the lumbar spine within 48 hours

Explanation

Cauda equina syndrome is an orthopedic emergency. The patient requires an urgent MRI to confirm the diagnosis (typically a massive central disc herniation) followed by prompt surgical decompression to prevent permanent neurological deficits.

Question 4667

Topic: 6. Spine

A 30-year-old man survives a high-speed motor vehicle accident and is diagnosed with a traumatic spondylolisthesis of the axis (Hangman's fracture). What is the most common classic mechanism of injury for this fracture in modern trauma settings?

. Hyperflexion and compression
. Hyperextension and axial loading
. Lateral bending and rotation
. Hyperextension and distraction
. Axial distraction and extreme flexion

Correct Answer & Explanation

. Hyperflexion and compression

Explanation

Traumatic spondylolisthesis of the axis (Hangman's fracture) in modern trauma is most commonly caused by hyperextension combined with axial loading (e.g., forehead striking the dashboard), unlike judicial hangings which involve hyperextension and distraction.

Question 4668

Topic: Cervical Spine

A 22-year-old diver hits his head on the bottom of a pool. Radiographs reveal a burst fracture of the C1 ring (Jefferson fracture). An open-mouth odontoid view shows an asymmetric overhang of the C1 lateral masses on C2 totaling 8 mm. This finding indicates disruption of which critical stabilizing structure?

. Apical ligament
. Alar ligament
. Transverse ligament
. Tectorial membrane
. Posterior longitudinal ligament

Correct Answer & Explanation

. Apical ligament

Explanation

The Rule of Spence dictates that a combined overhang of the C1 lateral masses on C2 of greater than 6.9 mm on an AP open-mouth radiograph implies disruption of the transverse ligament, rendering the C1 ring fracture highly unstable.

Question 4669

Topic: 6. Spine

A 40-year-old man presents with right-sided radiating leg pain, weakness in ankle dorsiflexion, and decreased sensation over the medial aspect of the foot. His patellar reflex is noticeably diminished. Which spinal nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

The L4 nerve root provides motor innervation for ankle dorsiflexion (tibialis anterior), sensory innervation to the medial foot, and mediates the patellar tendon reflex. This is commonly compressed by an L3-L4 posterolateral disc herniation or an L4-L5 far lateral herniation.

Question 4670

Topic: 6. Spine

A 72-year-old man with lumbar spinal stenosis experiences significant neurogenic claudication while walking. Which of the following postures typically provides symptomatic relief, and what is the biomechanical reason?

. Extension, because it increases the cross-sectional area of the spinal canal
. Extension, because it decreases tension on the lumbosacral nerve roots
. Flexion, because it decreases tension on the lumbosacral nerve roots
. Flexion, because it increases the cross-sectional area of the spinal canal
. Lateral bending, because it opens the contralateral intervertebral foramen

Correct Answer & Explanation

. Extension, because it increases the cross-sectional area of the spinal canal

Explanation

Patients with lumbar spinal stenosis often lean forward (shopping cart sign) because spinal flexion increases the anteroposterior diameter of the spinal canal and neural foramina, relieving compression on the cauda equina.

Question 4671

Topic: Thoracolumbar Spine & Deformity

A 16-year-old female presents after a high-speed motor vehicle collision where she was wearing only a lap belt. Imaging shows a horizontal fracture through the spinous process, pedicles, and vertebral body of L2 (Chance fracture). Which associated injury must be actively ruled out in this patient?

. Aortic transection
. Gastrointestinal hollow viscus injury
. Diaphragmatic rupture
. Renal laceration
. Splenic rupture

Correct Answer & Explanation

. Aortic transection

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of patients with a Chance fracture have an associated intra-abdominal hollow viscus injury (e.g., bowel perforation), which requires immediate general surgery evaluation.

Question 4672

Topic: 6. Spine

A 38-year-old woman presents with chronic axial low back pain. An MRI of her lumbar spine demonstrates Modic Type I changes at the L4-L5 endplates. What specific histological changes do Modic Type I signals represent?

. Endplate sclerosis and dense woven bone formation
. Fibrovascular replacement and edema of subchondral bone marrow
. Fatty replacement of subchondral bone marrow
. Avascular necrosis of the vertebral body endplate
. Benign intraosseous hemangioma formation

Correct Answer & Explanation

. Endplate sclerosis and dense woven bone formation

Explanation

Modic Type I changes on MRI (hypointense on T1, hyperintense on T2) represent fibrovascular replacement and edema of the subchondral bone marrow. Modic Type II represents fatty replacement, and Type III represents sclerotic bone.

Question 4673

Topic: 6. Spine

A 50-year-old woman presents with progressive leg weakness and hyperreflexia. MRI reveals a large, calcified central T8-T9 disc herniation causing severe cord compression. Which of the following surgical approaches is generally considered an absolute contraindication?

. Costotransversectomy
. Transthoracic anterior decompression
. Posterior laminectomy
. Lateral extracavitary approach
. Video-assisted thoracoscopic surgery (VATS)

Correct Answer & Explanation

. Costotransversectomy

Explanation

Standard posterior laminectomy is strictly contraindicated for central thoracic disc herniations. Retracting the thoracic spinal cord to access a central disc is highly likely to cause permanent neurological injury due to the cord's limited vascularity and mobility.

Question 4674

Topic: 6. Spine

A 60-year-old Asian male presents with progressive spastic gait and hand clumsiness. Radiographs and CT scans display a dense, flowing calcification along the posterior aspect of the cervical vertebral bodies extending from C3 to C6, severely narrowing the canal. What is the most likely diagnosis?

. Diffuse idiopathic skeletal hyperostosis (DISH)
. Ankylosing spondylitis
. Ossification of the posterior longitudinal ligament (OPLL)
. Osteitis deformans (Paget's disease)
. Calcium pyrophosphate deposition disease (CPPD)

Correct Answer & Explanation

. Diffuse idiopathic skeletal hyperostosis (DISH)

Explanation

OPLL is characterized by abnormal calcification of the posterior longitudinal ligament, most commonly in the cervical spine. It frequently presents in East Asian populations and causes progressive cervical myelopathy due to canal stenosis.

Question 4675

Topic: Thoracolumbar Spine & Deformity

In the evaluation of adult spinal deformity, which of the following spinopelvic parameters is considered a fixed, position-independent anatomical constant for an individual after they reach skeletal maturity?

. Pelvic tilt (PT)
. Sacral slope (SS)
. Pelvic incidence (PI)
. Lumbar lordosis (LL)
. Thoracic kyphosis (TK)

Correct Answer & Explanation

. Pelvic tilt (PT)

Explanation

Pelvic incidence (PI) is a morphological parameter that becomes fixed after skeletal maturity. It is critical in pre-operative planning as it dictates the required amount of lumbar lordosis for a balanced spine (LL = PI ± 9 degrees).

Question 4676

Topic: 6. Spine

A 45-year-old man presents after a motor vehicle collision with bilateral jumped facets at C5-C6. He has 0/5 strength in his deltoids and biceps bilaterally, and no sensation below the shoulders. He is fully awake and cooperative. What is the most appropriate next step in management after initial ATLS resuscitation?

. Emergent MRI of the cervical spine
. Awake closed reduction with Gardner-Wells tongs
. Immediate posterior cervical fusion
. High-dose methylprednisolone administration
. Anterior cervical discectomy and fusion

Correct Answer & Explanation

. Emergent MRI of the cervical spine

Explanation

For a patient with a neurologic deficit and bilateral facet dislocation who is awake and alert, emergent closed reduction is recommended before MRI to rapidly decompress the spinal cord. Awake closed reduction allows continuous neurologic monitoring during the procedure.

Question 4677

Topic: 6. Spine

According to the Rule of Spence, an injury to the transverse atlantal ligament should be highly suspected in a Jefferson (C1) burst fracture if the combined overhang of the C1 lateral masses on C2 exceeds which of the following measurements on an open-mouth odontoid view?

. 3 mm
. 5 mm
. 6.9 mm
. 9 mm
. 11 mm

Correct Answer & Explanation

. 3 mm

Explanation

A combined lateral mass overhang of C1 on C2 of 6.9 mm or greater on an AP open-mouth radiograph indicates a rupture of the transverse atlantal ligament. This suggests instability requiring halo immobilization or surgical stabilization.

Question 4678

Topic: 6. Spine
A 65-year-old man with a history of severe cervical spondylosis sustains a hyperextension injury. He presents with 2/5 strength in his upper extremities and 4/5 strength in his lower extremities. Which of the following spinal cord syndromes is he most likely experiencing?
. Anterior cord syndrome
. Central cord syndrome
. Brown-Séquard syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs after hyperextension injuries in older patients with pre-existing cervical stenosis. It is characterized by disproportionate motor impairment, with greater weakness in the upper extremities compared to the lower extremities.

Question 4679

Topic: Cervical Spine

Which of the following surgical factors is considered the strongest independent risk factor for the development of adjacent segment disease requiring surgery after an anterior cervical discectomy and fusion (ACDF)?

. Smoking
. Diabetes mellitus
. Plating within 5 mm of the adjacent unfused disc space
. Use of allograft instead of autograft
. Multilevel fusion

Correct Answer & Explanation

. Smoking

Explanation

Placement of an anterior cervical plate less than 5 mm from the adjacent unfused disc space significantly increases the risk of adjacent segment ossification and subsequent adjacent segment disease.

Question 4680

Topic: 6. Spine

A 55-year-old woman presents with persistent, severe right leg pain radiating down the lateral aspect of her leg to the dorsum of her foot. Examination reveals weakness in extensor hallucis longus and decreased sensation over the first dorsal web space. An MRI shows a far-lateral (extraforaminal) disc herniation at the L5-S1 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

Far-lateral (extraforaminal) disc herniations compress the exiting nerve root at the same level. Therefore, a far-lateral disc herniation at L5-S1 compresses the L5 nerve root, leading to EHL weakness and dorsal web space numbness.

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