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 1901
Topic: 6. Spine
A 65-year-old male with a 20-year history of ankylosing spondylitis presents to the emergency department with severe, localized lower thoracic back pain after slipping on ice. He denies any neurologic deficits. Initial plain radiographs of the thoracic and lumbar spine show no obvious fracture. What is the most appropriate next step in management?
Correct Answer & Explanation
. Obtain a CT scan of the entire spine
Explanation
Patients with ankylosing spondylitis have a rigid, osteopenic spine highly susceptible to unstable fractures from low-energy trauma. Plain radiographs often miss these fractures; therefore, a CT or MRI of the entire spine is mandatory.
Question 1902
Topic: 6. Spine
Based on the Spine Patient Outcomes Research Trial (SPORT) data for degenerative spondylolisthesis, which of the following statements best characterizes the long-term outcomes of surgical versus nonoperative treatment?
Correct Answer & Explanation
. Patients treated surgically maintain significantly greater improvement in pain and function compared to nonoperative cohorts.
Explanation
The SPORT trial demonstrated that patients who undergo surgery for degenerative spondylolisthesis have significantly better outcomes in pain and physical function at 4 and 8 years compared to those treated nonoperatively.
Question 1903
Topic: 6. Spine
A 55-year-old male with a history of intravenous drug use presents with excruciating lower back pain, fever, and elevated CRP. MRI reveals L3-L4 discitis and osteomyelitis. The infection in pyogenic spondylodiscitis in adults most commonly begins in which anatomic structure before spreading to the intervertebral disc?
Correct Answer & Explanation
. Vertebral body endplate
Explanation
In adults, pyogenic spondylodiscitis typically originates via hematogenous spread to the highly vascularized subchondral bone adjacent to the vertebral endplate. The avascular disc is subsequently infected via contiguous spread.
Question 1904
Topic: 6. Spine
A 62-year-old male with a history of prostate cancer complains of worsening, unrelenting nocturnal back pain. AP radiograph of the lumbar spine reveals the "winking owl" sign at L3. This radiographic finding represents destruction of which anatomic structure?
Correct Answer & Explanation
. Pedicle
Explanation
The "winking owl" sign on an AP spine radiograph indicates the destruction of a pedicle, often due to a metastatic lesion. The missing pedicle creates the appearance of a winking eye.
Question 1905
Topic: Cervical Spine
A 35-year-old female presents after a high-speed motor vehicle collision. Lateral cervical spine radiographs demonstrate approximately 25% anterior subluxation of the C4 vertebral body over C5. Which of the following injuries is most consistent with this radiographic finding?
Correct Answer & Explanation
. Unilateral facet dislocation
Explanation
Unilateral facet dislocations typically present with 25% anterior subluxation of the vertebral body on lateral plain films. Bilateral facet dislocations usually demonstrate 50% or greater anterior subluxation.
Question 1906
Topic: 6. Spine
A 67-year-old female is evaluated for a primary total hip arthroplasty. She has a prior L2-S1 spinal fusion. Preoperative dynamic spinopelvic radiographs show less than 10 degrees of change in pelvic tilt when transitioning from standing to sitting. To minimize her risk of posterior dislocation, how should the target placement of the acetabular component be adjusted?
Correct Answer & Explanation
. Increase anteversion compared to standard "safe zone" targets
Explanation
A stiff lumbopelvic junction prevents the pelvis from naturally tilting posteriorly during sitting, which normally increases functional acetabular anteversion. To compensate for this lack of dynamic clearance and prevent anterior impingement/posterior dislocation, the cup should be implanted with increased anteversion.
Question 1907
Topic: Thoracolumbar Spine & Deformity
A 45-year-old male presents with a T12 burst fracture after a fall. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), which of the following findings contributes the most points, strongly indicating the need for surgical stabilization?
Correct Answer & Explanation
. Disruption of the posterior ligamentous complex
Explanation
In the TLICS system, the integrity of the posterior ligamentous complex (PLC) is a critical determinant of mechanical stability. A definite PLC disruption scores 3 points, which, when combined with a burst fracture morphology (1 or 2 points), generally pushes the total score to >4, indicating operative management.
Question 1908
Topic: Thoracolumbar Spine & Deformity
A 16-year-old gymnast presents with persistent lower back pain. Radiographs reveal a pars interarticularis defect with a 25% anterior slip of L5 on S1. Which of the following best describes the classification of this spondylolisthesis?
Correct Answer & Explanation
. Isthmic
Explanation
Isthmic spondylolisthesis (Wiltse Type II) is caused by a stress fracture or defect in the pars interarticularis (spondylolysis). It is highly prevalent in adolescent athletes subjected to repetitive lumbar hyperextension, such as gymnasts and football linemen.
Question 1909
Topic: 6. Spine
A 45-year-old female presents with an L1 burst fracture. Examination reveals completely absent motor function below L1. Pinprick sensation is absent in the lower extremities, but light touch sensation is preserved at the S4-S5 dermatomes without voluntary anal sphincter contraction. What is her ASIA Impairment Scale grade?
Correct Answer & Explanation
. ASIA B
Explanation
ASIA B represents a sensory incomplete spinal cord injury. Sensation is preserved below the neurological level and includes the sacral segments S4-S5, but there is no motor function preserved more than three levels below the motor level on either side.
Question 1910
Topic: 6. Spine
A 65-year-old man presents with progressive hand clumsiness, gait instability, a positive Hoffmann's sign, and hyperreflexia. Radiographs demonstrate multi-level cervical spondylosis. Which of the following radiographic findings would most strongly favor an anterior surgical approach over a posterior laminectomy?
Correct Answer & Explanation
. Fixed cervical kyphosis
Explanation
In cervical spondylotic myelopathy, the presence of fixed cervical kyphosis is a strong indication for an anterior (or combined) approach. A posterior laminectomy alone in a kyphotic spine fails to adequately decompress the spinal cord, as it remains tethered tightly over anterior osteophytes.
Question 1911
Topic: 6. Spine
A 65-year-old male presents with deteriorating handwriting, frequent dropping of objects, and a broad-based, unsteady gait. Physical examination reveals a positive Hoffmann sign and hyperreflexia in both lower extremities. What is the most appropriate next step in management?
Correct Answer & Explanation
. Magnetic resonance imaging (MRI) of the cervical spine.
Explanation
The patient's presentation of hand clumsiness, gait instability, and upper motor neuron signs indicates cervical spondylotic myelopathy. An MRI of the cervical spine is the gold standard diagnostic study to evaluate spinal cord compression.
Question 1912
Topic: Thoracolumbar Spine & Deformity
A 45-year-old male sustains an L1 burst fracture after a fall from a roof. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex. His Thoracolumbar Injury Classification and Severity (TLICS) score is calculated as 2. What is the most appropriate evidence-based recommendation?
Correct Answer & Explanation
. Conservative management with a rigid thoracolumbosacral orthosis (TLSO).
Explanation
A TLICS score of less than 4 (in this case: morphology=burst (2), neuro=intact (0), PLC=intact (0); total=2) indicates non-operative management. Conservative treatment with bracing or early mobilization is the standard of care for stable, neurologically intact thoracolumbar burst fractures.
Question 1913
Topic: 6. Spine
A 62-year-old male presents with deteriorating handwriting, difficulty buttoning his shirt, and a broad-based, unsteady gait. Physical exam reveals a positive Hoffmann's sign. MRI shows cervical spondylosis with cord compression at C5-C6. What is the most appropriate management?
Correct Answer & Explanation
. Surgical decompression
Explanation
Cervical spondylotic myelopathy is generally a progressive condition. Once objective clinical signs of myelopathy (gait instability, loss of fine motor skills, positive upper motor neuron signs) are present, surgical decompression is indicated to arrest progression.
Question 1914
Topic: 6. Spine
An examiner presents a 45-year-old male with acute back pain, bilateral sciatica, and new-onset urinary retention. The MRI shows a massive L4-L5 disc herniation. The examiner asks, 'How long can you safely wait before operating?' What is the most definitive clinical answer?
Correct Answer & Explanation
. Emergent surgical decompression should be performed, ideally within 24 to 48 hours, to maximize the chance of neurologic recovery.
Explanation
Cauda equina syndrome with urinary retention is an orthopedic emergency requiring urgent decompression, ideally within 24 to 48 hours. Delays beyond this timeframe are associated with significantly poorer outcomes in bladder and bowel function.
Question 1915
Topic: 6. Spine
A 65-year-old female presents with deteriorating handwriting, frequent tripping, and hyperreflexia. MRI shows cervical stenosis at C4-C5. Which of the following physical exam findings is most specific for this condition?
Correct Answer & Explanation
. Positive Hoffmann sign
Explanation
The Hoffmann sign is indicative of an upper motor neuron lesion. In the context of cervical stenosis, it is highly suggestive of cervical myelopathy.
Question 1916
Topic: 6. Spine
A 35-year-old active patient undergoes a routine orthopedic evaluation. A full-length standing anteroposterior radiograph is performed, and the mechanical axis is found to pass 6 mm medial to the tibial spines. Based on Paley's foundational principles, what is the correct interpretation of this finding?
Correct Answer & Explanation
. This represents a normal mechanical axis alignment, falling within the physiological range.
Explanation
Correct Answer: CThe teaching case explicitly states: 'In a perfectly aligned, normal limb, this mechanical axis line should pass directly through the center of the knee joint, or slightly medial to it (typically 1 to 8 mm medial to the tibial spines, falling within the medial compartment).' A MAD of 6 mm medial to the tibial spines falls squarely within this normal physiological range. Therefore, this patient has a normal mechanical axis alignment.Option A is incorrect as it is within the normal range, not a significant varus deformity. Option B is incorrect as it is a normal varus alignment, not valgus. Option D is incorrect; while other imaging may be needed for specific pathologies, the MAD itself is conclusive for global alignment in this range. Option E is incorrect as it describes a valgus deformity, which is the opposite of the finding.
Question 1917
Topic: 6. Spine
The mechanical axis is a fundamental concept in lower extremity deformity analysis. Which of the following statements accurately describes the mechanical axis and its significance in a healthy, well-aligned limb?
Correct Answer & Explanation
. It is the true line of weight-bearing, drawn from the center of the femoral head to the center of the ankle plafond, and normally bisects the knee joint.
Explanation
Correct Answer: BThe case clearly defines the mechanical axis: 'The mechanical axis is the true line of weight-bearing. In the lower extremity, it is drawn from the center of the femoral head to the center of the ankle plafond. In a perfectly aligned, healthy limb, this line bisects the knee joint, passing slightly medial to the tibial spines.' Normalizing the Mechanical Axis Deviation (MAD) is the ultimate goal of corrective osteotomy to normalize joint loading and prevent osteoarthritis progression.Option A is incorrect; it incorrectly states the origin (greater trochanter instead of femoral head) and the normal path (lateral compartment instead of bisecting the knee). Option C describes the anatomical axis, not the mechanical axis, and misstates its primary use. Option D is incorrect; the mechanical axis is about weight-bearing and alignment, not muscle pull or primarily rotational deformities. Option E is incorrect; it misidentifies the origin and destination points of the mechanical axis.
Question 1918
Topic: 6. Spine
A 22-year-old male presents with intractable right L5 radiculopathy and severe low back pain, unresponsive to NSAIDs. CT scan reveals an osteoid osteoma nidus within the right L5 pedicle, with significant reactive sclerosis impinging on the neural foramen. The surgical team plans an open excision. During the approach, what is the most critical anatomical structure to protect, given the lesion's location and the patient's symptoms?
Correct Answer & Explanation
. The traversing L5 nerve root.
Explanation
Correct Answer: CExplanation:The case highlights that pedicles define the medial and lateral boundaries of the spinal canal and superior and inferior boundaries of the neural foramen. It explicitly states, 'Lesions within the pedicle can directly impinge upon traversing nerve roots or the spinal cord itself, necessitating precise localization and careful resection.' The patient's presentation with L5 radiculopathy directly implicates the L5 nerve root as the structure being compressed and therefore the most critical to protect during resection of a pedicle lesion. Damage to this nerve root could worsen the patient's neurological deficit.Option A (The superior articular process of L5):While important for facet joint integrity, it is not the primary structure causing radiculopathy from a pedicle lesion, nor is its protection as critical as the nerve root in this scenario.Option B (The L5 spinous process):The spinous process is a posterior midline structure, generally remote from a pedicle lesion causing neural foramen impingement.Option D (The L4-L5 interspinous ligament):This ligament is important for spinal stability but is not directly impinged by a pedicle lesion causing radiculopathy, nor is it the most critical structure to protect in this context.Option E (The L5 transverse process):The transverse process is a lateral projection. While a lesion here could be problematic, a pedicle lesion causing radiculopathy is more directly related to the neural foramen and the nerve root.
Question 1919
Topic: 6. Spine
A 19-year-old male is scheduled for open surgical excision of an osteoid osteoma located in the L3 lamina. The surgeon plans a posterior midline approach. Which of the following best describes the primary internervous plane utilized during the subperiosteal dissection to expose the posterior elements?
Correct Answer & Explanation
. Between the erector spinae group and deeper muscles like the multifidus.
Explanation
Correct Answer: CExplanation:The case explicitly states: 'For posterior approaches to the spine, the primary internervous plane is typically between the erector spinae group (innervated by posterior rami of spinal nerves) and deeper muscles like the multifidus (also innervated by posterior rami). Subperiosteal dissection directly off the spinous processes and laminae minimizes muscle damage and preserves vascularity.' This describes the anatomical plane used to access the posterior elements of the spine while minimizing damage to muscle innervation.Option A (Between the psoas major and quadratus lumborum muscles):This plane is relevant for anterior or anterolateral approaches to the lumbar spine, not a posterior midline approach.Option B (Between the rectus abdominis and external oblique muscles):These are anterior abdominal wall muscles, irrelevant for a posterior spinal approach.Option D (Between the latissimus dorsi and trapezius muscles):These are superficial back muscles, but the primary internervous plane for deep spinal exposure is deeper, involving the erector spinae group.Option E (Between the gluteus maximus and gluteus medius muscles):These are gluteal muscles, relevant for hip or pelvic surgery, not a direct posterior spinal approach.
Question 1920
Topic: 6. Spine
A 10-year-old boy presents with a painful scoliosis and an osteoid osteoma in the T7 lamina. The lesion is located very close to the spinal cord, and there is concern about potential thermal injury to neural structures if percutaneous radiofrequency ablation (RFA) is attempted. Which of the following is the most appropriate management strategy in this scenario?
Correct Answer & Explanation
. Perform open surgical excision.
Explanation
Correct Answer: CExplanation:The case outlines specific operative indications, including 'Atypical Location/Deep Lesions: Lesions that are technically challenging or unsafe for percutaneous ablation due to proximity to critical neurovascular structures (e.g., spinal cord, major nerve roots, major vessels) or complex anatomy.' In this scenario, the proximity to the spinal cord makes RFA risky due to thermal injury. Therefore, open surgical excision, which allows for direct visualization and precise removal while protecting neural structures, becomes the most appropriate management strategy.Option A (Proceed with RFA, but use a lower temperature setting):Lowering the temperature may reduce efficacy and still pose a risk to the spinal cord. This does not negate the fundamental safety concern.Option B (Observe with NSAIDs, as spontaneous resolution is common in children):The patient has painful scoliosis, which is a progressive deformity and an indication for intervention. Spontaneous resolution is less common in spinal lesions, and observation would allow the deformity to worsen.Option D (Attempt cryoablation (CNA) as a safer percutaneous alternative):While cryoablation is an alternative to RFA, the case mentions it as 'an effective alternative with similar success rates' but does not explicitly state it is inherently safer near the spinal cord in all situations. The primary concern is proximity to critical neural structures, which often makes any percutaneous ablation risky, favoring open excision for direct visualization and protection.Option E (Administer systemic chemotherapy to shrink the lesion):Osteoid osteoma is a benign tumor and does not respond to chemotherapy.
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