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6. Spine MCQs

Practice Set 243 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 4841

Topic: 6. Spine

A 42-year-old male is involved in a motor vehicle collision and sustains a fracture of the L1 vertebra. A CT scan demonstrates a burst morphology with retropulsion into the spinal canal. Neurological examination reveals 3/5 strength in the bilateral tibialis anterior and extensor hallucis longus, with intact sensation. An MRI confirms the posterior ligamentous complex (PLC) is entirely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is this patient's total score and the recommended management category?

. TLICS Score of 3; Non-operative management
. TLICS Score of 4; Surgeon's choice
. TLICS Score of 5; Operative management
. TLICS Score of 6; Operative management
. TLICS Score of 7; Operative management

Correct Answer & Explanation

. TLICS Score of 5; Operative management

Explanation

The TLICS system scores three categories: Morphology, Neurologic Status, and PLC integrity. For this patient: Morphology is Burst = 2 points. Neurologic status is Incomplete spinal cord / cauda equina injury = 3 points. PLC is Intact = 0 points. Total Score = 5 points. A score of less than 4 recommends non-operative treatment, exactly 4 is indeterminate (surgeon's choice), and 5 or more recommends operative management. Therefore, the score is 5, making it an operative indication.

Question 4842

Topic: Thoracolumbar Spine & Deformity

A 68-year-old woman presents with progressive severe mechanical low back pain, early satiety, and an inability to stand upright for more than 10 minutes without supporting herself on a walker (flatback syndrome). Standing full-length radiographs are obtained. Her pelvic incidence (PI) is 60 degrees, and her pelvic tilt (PT) is 35 degrees. To achieve optimal sagittal spinopelvic balance during a planned multi-level adult spinal deformity reconstruction, the postoperative goal for her lumbar lordosis (LL) should be approximately:

. 25 degrees
. 35 degrees
. 40 degrees
. 60 degrees
. 85 degrees

Correct Answer & Explanation

. 60 degrees

Explanation

In adult spinal deformity surgery, achieving appropriate sagittal balance is critical to prevent adjacent segment failure and improve patient outcomes. The key relationship is that Lumbar Lordosis (LL) should be matched to the patient's Pelvic Incidence (PI) to within approximately 9 to 10 degrees (PI - LL < 10°). Since this patient's PI is 60 degrees, the target LL should be approximately 50-60 degrees. Therefore, 60 degrees is the most appropriate target among the choices provided.

Question 4843

Topic: Thoracolumbar Spine & Deformity

A 16-year-old elite male gymnast presents with a 9-month history of mechanical low back pain that has not improved despite rigorous non-operative management, including bracing, physical therapy, and rest. Imaging reveals an L4 bilateral isthmic spondylolysis with no measurable spondylolisthesis. An MRI shows healthy, well-hydrated discs at L3-L4, L4-L5, and L5-S1. What is the most appropriate surgical treatment?

. L4-L5 posterior lumbar interbody fusion (PLIF)
. Direct pars interarticularis repair at L4
. L4-L5 anterior lumbar interbody fusion (ALIF)
. L4-L5 posterolateral instrumented fusion without interbody support
. L3-L5 posterolateral instrumented fusion

Correct Answer & Explanation

. Direct pars interarticularis repair at L4

Explanation

Direct pars repair is indicated in young patients (typically adolescents or young adults) with symptomatic isthmic spondylolysis who have failed conservative treatment, provided there is minimal or no spondylolisthesis (Grade 1 or less) and no significant disc degeneration on MRI. It is particularly successful for defects at L1 to L4. At L5, the biomechanical forces make direct repair more prone to failure, though it is sometimes still attempted; however, at L4 with a healthy adjacent disc, a direct pars repair preserves motion segments and avoids the need for a fusion.

Question 4844

Topic: 6. Spine

A 28-year-old male is brought to the trauma bay obtunded and intubated after falling from a 20-foot scaffold. Cervical spine radiographs and a non-contrast CT demonstrate a right-sided unilateral C5-C6 facet dislocation. His Glasgow Coma Scale is 3T, and he cannot participate in a neurological examination. What is the most appropriate next step in the management of his cervical spine injury?

. Immediate closed reduction using Gardner-Wells tongs with progressively increasing weight
. Emergent anterior cervical discectomy and fusion (ACDF) without further imaging
. Emergent posterior cervical open reduction and fusion without further imaging
. Magnetic resonance imaging (MRI) of the cervical spine
. Application of a halo vest and reassessment when the patient awakens

Correct Answer & Explanation

. Magnetic resonance imaging (MRI) of the cervical spine

Explanation

In a patient with a cervical facet dislocation who is unexaminable (e.g., obtunded, intubated, or intoxicated), it is critical to obtain an MRI prior to attempting either closed or open reduction. This is to rule out a herniated disc behind the vertebral body. Reducing a dislocated facet in the presence of a large extruded disc can result in the disc being dragged into the canal, causing an iatrogenic spinal cord injury. If an awake, alert, and examinable patient were presented, a closed reduction could be attempted prior to MRI with serial neurological exams after every weight addition.

Question 4845

Topic: 6. Spine

A 60-year-old man with poorly controlled diabetes mellitus and chronic kidney disease presents with a 2-week history of unrelenting mid-back pain, low-grade fevers, and night sweats. Neurologic examination of his bilateral lower extremities is entirely normal. Blood tests reveal an erythrocyte sedimentation rate (ESR) of 90 mm/hr and a C-reactive protein (CRP) of 15 mg/L. MRI of the thoracic spine demonstrates a well-circumscribed posterior epidural abscess from T7 to T9, with no significant spinal cord compression. What is the most appropriate initial management step?

. Empiric intravenous vancomycin and ceftriaxone, followed by bracing
. Emergent open surgical laminectomy, decompression, and debridement
. CT-guided needle aspiration of the epidural collection for microbiology, followed by targeted antibiotics
. Administration of high-dose intravenous dexamethasone
. Outpatient management with oral linezolid and close clinical follow-up

Correct Answer & Explanation

. CT-guided needle aspiration of the epidural collection for microbiology, followed by targeted antibiotics

Explanation

This patient has a spinal epidural abscess (SEA) without neurologic deficits and without significant cord compression. Current guidelines (e.g., IDSA) support medical management for SEA in neurologically intact and clinically stable patients. However, obtaining a precise microbiological diagnosis is critical before initiating prolonged antibiotics, as blood cultures are negative in up to 40% of cases. Therefore, a CT-guided aspiration of the fluid collection is recommended prior to initiating antibiotics, provided the patient does not deteriorate neurologically. Emergent surgical decompression is reserved for cases with developing neurologic deficits, spinal instability, or failure of medical management.

Question 4846

Topic: 6. Spine

During an anterior cervical discectomy and fusion (ACDF) at the C6-C7 level, the surgeon must decide whether to approach the spine from the left or the right side. While right-handed surgeons often prefer a right-sided approach for ergonomics, many surgeons specifically advocate for a left-sided approach in the lower cervical spine to minimize the risk of injury to the recurrent laryngeal nerve (RLN). Which anatomical feature best explains this preference?

. The left RLN branches off the vagus nerve more superiorly in the neck than the right RLN.
. The right RLN travels within the carotid sheath, making it highly vulnerable to medial retraction.
. The right RLN is more likely to be a non-recurrent nerve due to a retropharyngeal path.
. The left RLN has a more consistent and protected vertical course within the tracheoesophageal groove.
. The left RLN is functionally redundant, so unilateral injury is asymptomatic.

Correct Answer & Explanation

. The left RLN has a more consistent and protected vertical course within the tracheoesophageal groove.

Explanation

The left recurrent laryngeal nerve (RLN) loops under the arch of the aorta and ascends into the neck with a very consistent, protected, and vertical course within the tracheoesophageal groove. In contrast, the right RLN loops under the right subclavian artery and ascends towards the larynx in a more oblique and variable course, crossing from lateral to medial. This oblique orientation on the right makes it more vulnerable to traction injury during retractor placement, especially at lower cervical levels (C6-T1). Furthermore, the rare 'non-recurrent' laryngeal nerve (approx. 1% of the population) almost exclusively occurs on the right side.

Question 4847

Topic: 6. Spine



A 45-year-old man presents with acute onset of severe left-sided radiating leg pain following a twisting injury. Physical examination demonstrates 4/5 weakness in left knee extension, a diminished left patellar reflex, and decreased pinprick sensation over the medial aspect of the left lower leg. An MRI of the lumbar spine confirms a single-level extraforaminal (far lateral) disc herniation. Given the clinical presentation, what is the most likely location of the herniation?

. Far lateral disc herniation at L2-L3
. Far lateral disc herniation at L3-L4
. Far lateral disc herniation at L4-L5
. Paracentral disc herniation at L4-L5
. Paracentral disc herniation at L3-L4

Correct Answer & Explanation

. Far lateral disc herniation at L4-L5

Explanation

The patient's physical examination indicates an L4 radiculopathy (weakness in knee extension/quadriceps, diminished patellar reflex, medial lower leg sensory loss). In the lumbar spine, a paracentral disc herniation typically impinges on the traversing nerve root (e.g., a paracentral L3-L4 herniation compresses the L4 root). Conversely, a far lateral (extraforaminal) disc herniation impinges on the exiting nerve root at the same level. Therefore, a far lateral disc herniation at L4-L5 would compress the exiting L4 nerve root, causing the described L4 radiculopathy.

Question 4848

Topic: 6. Spine

In a patient with cervical myelopathy secondary to ossification of the posterior longitudinal ligament (OPLL), the 'K-line' is frequently utilized on sagittal imaging to guide surgical decision-making. Which of the following statements is true regarding a 'K-line negative' cervical spine?

. The K-line connects the anterior margins of the vertebral bodies from C2 to C7.
. A K-line negative spine indicates a hyperlordotic cervical sagittal alignment.
. The OPLL mass exceeds the K-line posteriorly, and posterior decompression alone will likely yield poor neurological recovery.
. The OPLL mass does not cross the K-line, making cervical laminoplasty the preferred and most effective surgical approach.
. It represents an absolute contraindication to an anterior cervical corpectomy and fusion.

Correct Answer & Explanation

. The OPLL mass exceeds the K-line posteriorly, and posterior decompression alone will likely yield poor neurological recovery.

Explanation

The K-line is a straight line connecting the midpoints of the spinal canal at C2 and C7 on a neutral lateral radiograph or sagittal CT/MRI. In a 'K-line negative' spine, the OPLL mass exceeds the K-line (crosses it posteriorly), which is typically seen in kyphotic alignment or cases with a very large OPLL mass. Under these conditions, the spinal cord will not shift posteriorly enough following a posterior decompression (like laminoplasty), resulting in inadequate cord decompression and poor neurological recovery. Therefore, an anterior decompression or a combined/posterior approach with deformity correction is favored.

Question 4849

Topic: Cervical Spine

An 82-year-old man falls from a standing height and sustains a Type II odontoid fracture with 3 mm of posterior displacement. He is neurologically intact. He has a past medical history of severe chronic obstructive pulmonary disease (COPD) and ischemic heart disease. What is the most appropriate initial management?

. Halo vest immobilization
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation
. Rigid cervical collar immobilization
. Posterior C1-C2 polyaxial screw and rod fixation

Correct Answer & Explanation

. Rigid cervical collar immobilization

Explanation

In the elderly population (especially those >80 years old) with significant medical comorbidities, the morbidity and mortality associated with operative intervention or halo vest immobilization are exceedingly high. Halo vests, in particular, severely restrict respiration and are poorly tolerated by patients with COPD, often leading to pneumonia or respiratory failure. For Type II odontoid fractures in frail, elderly patients, nonoperative management with a rigid cervical collar is recommended. Although the nonunion rate is higher with a collar than with surgery, the nonunions are typically stable fibrous unions that are well-tolerated, thus safely avoiding perioperative complications.

Question 4850

Topic: 6. Spine

A 45-year-old man underwent an L4-L5 microdiscectomy 6 weeks ago with complete resolution of his preoperative radicular symptoms. He now presents with recurrent right leg pain in the L5 distribution following a violent sneezing episode. MRI with contrast demonstrates a recurrent focal disc extrusion at L4-L5 on the right. Physical examination reveals 4/5 weakness in the extensor hallucis longus and severe pain refractory to oral medications. Flexion-extension radiographs show no evidence of spondylolisthesis or instability. What is the most appropriate surgical management?

. Epidural steroid injection
. L4-L5 anterior lumbar interbody fusion (ALIF)
. L4-L5 posterior instrumented fusion
. Revision microdiscectomy
. Translaminar epiduroscopic discectomy

Correct Answer & Explanation

. Revision microdiscectomy

Explanation

For a patient experiencing a recurrent symptomatic lumbar disc herniation in the early postoperative period accompanied by progressive motor weakness or intractable pain, a revision microdiscectomy is the procedure of choice. Lumbar fusion is generally reserved for patients presenting with predominant mechanical back pain, documented spinal instability, or multiple herniation recurrences with significant disc height collapse and foraminal stenosis. A single early recurrence presenting with pure radiculopathy and an extruded disc fragment can be safely and effectively treated with a repeat discectomy.

Question 4851

Topic: 6. Spine
A 65-year-old man with pre-existing cervical spondylosis sustains a hyperextension injury to his neck in a low-speed motor vehicle collision. He presents with severe bilateral upper extremity weakness (motor score 1/5 in hands, 3/5 in shoulders) and mild lower extremity weakness (motor score 4/5). He has patchy sensory loss below the shoulders but maintains intact perianal sensation. Which of the following best describes the expected prognosis and rationale for early (<24 hours) versus delayed surgery?
. Early surgery is mandatory to prevent progression to a complete spinal cord injury.
. Delayed surgery has been definitively shown to result in significantly better long-term neurological recovery than early surgery.
. Early surgery may improve neurological outcomes and reduce hospital length of stay, but the absolute timing remains controversial.
. Surgical decompression is strictly contraindicated in central cord syndrome without associated fracture or dislocation.
. The patient has a poor prognosis for regaining ambulatory capacity regardless of surgical timing.

Correct Answer & Explanation

. Early surgery may improve neurological outcomes and reduce hospital length of stay, but the absolute timing remains controversial.

Explanation

This patient's presentation is classic for acute traumatic central cord syndrome (CCS), typically occurring after a hyperextension injury in a stenotic cervical spine. Recent literature, including the STASCIS trial and subsequent subgroup analyses, suggests that early surgical decompression (<24 hours) is safe, may provide improved neurological recovery, and often reduces hospital length of stay compared to delayed surgery. However, unlike acute complete cord injuries with ongoing compression, the absolute timing of surgery for CCS remains debated and lacks a universally mandated timeline. The prognosis for regaining ambulation in CCS is generally favorable, although fine motor function in the hands often remains permanently impaired.

Question 4852

Topic: Thoracolumbar Spine & Deformity

A 16-year-old elite gymnast presents with a 3-month history of insidious-onset, activity-related lower back pain that worsens with lumbar extension. Neurological examination is unremarkable. Plain standing anterior-posterior, lateral, and oblique radiographs demonstrate no obvious pars interarticularis defect or spondylolisthesis. What is the most appropriate next imaging modality to evaluate for an acute or active spondylolysis?

. Computed tomography (CT) scan of the lumbar spine
. Technetium-99m whole-body bone scan
. Single-photon emission computed tomography (SPECT)
. Flexion-extension lumbar radiographs
. Magnetic resonance imaging (MRI) of the lumbar spine

Correct Answer & Explanation

. Magnetic resonance imaging (MRI) of the lumbar spine

Explanation

In pediatric and adolescent patients with suspected acute pars interarticularis stress reactions or fractures (spondylolysis) who have normal plain radiographs, MRI of the lumbar spine is currently the advanced imaging modality of choice. STIR or T2 fat-suppressed MRI sequences provide high sensitivity for detecting bone marrow edema in the pars interarticularis, indicating an active stress reaction. MRI avoids the significant ionizing radiation exposure associated with CT and SPECT scans, which is a critical consideration in the pediatric population.

Question 4853

Topic: 6. Spine

A 65-year-old woman presents with progressive low back pain and an inability to stand up straight. Standing full-length spine radiographs reveal a pelvic incidence (PI) of 60°, lumbar lordosis (LL) of 20°, pelvic tilt (PT) of 35°, and sagittal vertical axis (SVA) of +12 cm. What is the minimum recommended degree of lumbar lordosis restoration required to optimize her post-operative clinical outcome?

. 20°
. 30°
. 50°
. 70°
. 90°

Correct Answer & Explanation

. 50°

Explanation

According to the SRS-Schwab classification of adult spinal deformity, optimal sagittal alignment targets include SVA < 5 cm, PT < 20°, and PI-LL mismatch within ±10°. For a PI of 60°, the target LL should be at least 50° (60° - 10°). Restoring LL to 50° or more will likely reduce SVA and PT, rebalancing the patient's global sagittal alignment and improving clinical outcomes.

Question 4854

Topic: 6. Spine

A 65-year-old man presents with progressive gait imbalance and loss of fine motor skills. Examination reveals hyperreflexia and a positive Babinski sign. MRI of the cervical spine demonstrates multi-level stenosis from C3 to C6 due to ossification of the posterior longitudinal ligament (OPLL). A line drawn from the mid-point of the spinal canal at C2 to the mid-point at C7 (K-line) on a neutral sagittal image shows that the OPLL mass crosses anterior to posterior over this line (K-line negative). Which of the following surgical approaches is most strongly indicated?

. Cervical laminoplasty
. Cervical laminectomy without fusion
. Anterior cervical decompression and fusion
. Cervical disc arthroplasty
. Posterior foraminotomy

Correct Answer & Explanation

. Anterior cervical decompression and fusion

Explanation

The K-line is used to predict the outcome of posterior decompression for OPLL. A K-line negative OPLL (where the peak of the OPLL exceeds the K-line) indicates that the spinal cord will not shift posteriorly enough after a posterior decompression (e.g., laminoplasty or laminectomy) to adequately relieve the anterior compression. Therefore, an anterior decompression and fusion (or combined anterior-posterior approach) is indicated to directly remove the compressive pathology.

Question 4855

Topic: Thoracolumbar Spine & Deformity

A 35-year-old male falls from a 15-foot ladder and sustains an L1 burst fracture. His neurological examination is completely normal (ASIA E). A CT scan shows 45% canal compromise and 20 degrees of local kyphosis. An MRI confirms an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the most appropriate management?

. High-dose methylprednisolone and observation
. Rigid TLSO bracing and early mobilization
. Posterior spinal fusion L1-L2
. Anterior L1 corpectomy and fusion
. Percutaneous pedicle screw fixation T12-L2

Correct Answer & Explanation

. Rigid TLSO bracing and early mobilization

Explanation

The TLICS score is calculated as follows: Morphology of a burst fracture = 2 points; Neurologic status of intact = 0 points; PLC status of intact = 0 points. The total score is 2. A TLICS score of 3 or less suggests non-operative management. Rigid bracing and early mobilization is the standard of care for neurologically intact burst fractures with an intact PLC, regardless of the absolute degree of canal compromise.

Question 4856

Topic: 6. Spine

A 55-year-old diabetic male presents with 2 weeks of worsening mid-back pain, low-grade fevers, and new-onset lower extremity weakness (motor strength 3/5 bilaterally). He also reports urinary retention. An MRI reveals a large ventral epidural abscess at T6-T8 with severe spinal cord compression. Broad-spectrum intravenous antibiotics are initiated. What is the next best step in management?

. CT-guided needle aspiration
. Observation with repeat MRI in 48 hours
. Urgent posterior decompressive laminectomy
. Urgent anterior debridement and decompression
. High-dose dexamethasone alone

Correct Answer & Explanation

. Urgent anterior debridement and decompression

Explanation

Epidural abscesses causing progressive neurological deficits require urgent surgical decompression. Because the abscess is located ventrally in the thoracic spine, a posterior laminectomy alone is contraindicated as it is associated with poor outcomes, inadequate decompression, and potential iatrogenic destabilization. An anterior approach (e.g., corpectomy, costotransversectomy, or transpedicular approach) for direct ventral debridement and decompression is indicated.

Question 4857

Topic: 6. Spine

A 70-year-old man with a known history of severe ankylosing spondylitis presents to the emergency department after a minor low-speed motor vehicle collision. He reports new-onset severe neck pain but has no neurological deficits. Initial plain radiographs of the cervical spine are obscured by cervicothoracic kyphosis and osteopenia, making them difficult to interpret. What is the most appropriate next step in management?

. Discharge with a soft cervical collar and outpatient follow-up
. Flexion-extension cervical spine radiographs
. MRI of the cervical spine as the primary bony diagnostic tool
. CT scan of the entire cervical spine
. Empiric halo vest immobilization

Correct Answer & Explanation

. CT scan of the entire cervical spine

Explanation

Patients with ankylosing spondylitis are at an extremely high risk for highly unstable extension-distraction fractures of the cervical spine, even after minor trauma. Plain radiographs are notoriously inadequate in these patients due to altered anatomy. A CT scan of the entire cervical spine is the gold standard and most appropriate next step for identifying occult fractures. MRI is supplementary for assessing epidural hematoma or ligamentous injury, but CT is paramount for bony architecture.

Question 4858

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast complains of persistent mechanical low back pain for 6 months. Radiographs demonstrate a Grade II L5-S1 isthmic spondylolisthesis. Non-operative management, including bracing, physical therapy, and activity modification, has failed. She is now scheduled for an in situ posterolateral L5-S1 fusion. Which of the following slip parameters is most associated with a high risk of progression and nonunion?

. Sacral slope less than 30 degrees
. High slip angle (lumbosacral kyphosis)
. Pelvic incidence equal to lumbar lordosis
. L4-L5 disc degeneration
. Intact iliolumbar ligaments

Correct Answer & Explanation

. High slip angle (lumbosacral kyphosis)

Explanation

The slip angle (or lumbosacral angle) measures the degree of lumbosacral kyphosis. A high slip angle (typically > 40-50 degrees) is a hallmark of a highly unstable, dysplastic pattern in isthmic spondylolisthesis. It indicates a significant risk for slip progression and nonunion, even after an in situ fusion, frequently necessitating reduction and interbody support.

Question 4859

Topic: 6. Spine

A 60-year-old woman with a 20-year history of severe rheumatoid arthritis presents with neck pain and occipital headaches. Lateral cervical spine radiographs in flexion and extension show an anterior atlantodens interval (ADI) of 8 mm. Which of the following is the most critical radiographic parameter to measure to determine the risk of impending neurologic injury?

. Posterior atlantodens interval (PADI) / Space available for the cord (SAC)
. Wackenheim's line
. Powers ratio
. Ranawat criterion
. C2-C7 sagittal vertical axis

Correct Answer & Explanation

. Posterior atlantodens interval (PADI) / Space available for the cord (SAC)

Explanation

In atlantoaxial subluxation associated with rheumatoid arthritis, while the anterior ADI is used to diagnose instability (> 3.5 mm in adults), the posterior atlantodens interval (PADI), also known as the space available for the cord (SAC), is the most important predictor of neurologic compromise. A PADI/SAC of < 14 mm is associated with a high risk of neurologic injury and is a strong indication for surgical stabilization.

Question 4860

Topic: 6. Spine

During a routine L4-L5 lumbar microdiscectomy for a herniated disc, an incidental durotomy is encountered. A primary water-tight repair is successfully performed with 4-0 Nurolon. A Valsalva maneuver confirms no further cerebrospinal fluid (CSF) leak. What is the most appropriate post-operative management strategy regarding patient mobilization?

. Absolute flat bedrest for 7 days
. Lumbar subarachnoid drain placement for 3 days
. Early mobilization without bedrest restrictions
. Continuous epidural suction drainage
. Trendelenburg positioning for 48 hours

Correct Answer & Explanation

. Early mobilization without bedrest restrictions

Explanation

Recent literature regarding incidental durotomies that are repaired primarily during lumbar spine surgery supports early mobilization. Prolonged bedrest has not been shown to decrease the risk of post-operative CSF leak or pseudomeningocele formation and is associated with increased medical complications such as deep vein thrombosis, atelectasis, and prolonged hospital stay.

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