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 1701
Topic: 6. Spine
A 30-year-old male treated non-operatively for a displaced Denis Zone II sacral fracture develops severe, intractable neurogenic pain in the lower extremity 6 months post-injury. What is the most likely cause?
Correct Answer & Explanation
. Sacral nerve root entrapment in the healing foraminal callus
Explanation
Denis Zone II fractures involve the sacral foramina. Non-operative management of displaced fractures can lead to foraminal stenosis and nerve root entrapment within the healing bony callus, causing intractable radicular pain.
Question 1702
Topic: 6. Spine
Which of the following best describes the anatomic location and the most common neurological injury associated with a Denis Zone II sacral fracture?
Correct Answer & Explanation
. Through the sacral foramina; S1/S2 radiculopathy
Explanation
Denis Zone II fractures occur directly through the sacral foramina and are associated with a 28% rate of neurological deficit. The most common deficit involves radiculopathy of the exiting nerve roots within the foramina, typically S1 or S2.
Question 1703
Topic: 6. Spine
A 28-year-old female presents with an isolated Denis Zone I sacral fracture after a fall from a height. Despite the fracture being lateral to the foramina, she exhibits weakness in ankle dorsiflexion and great toe extension. What is the most likely cause of her neurological deficit?
Correct Answer & Explanation
. Direct compression of the L5 nerve root by a transverse process fracture
Explanation
Denis Zone I fractures (alar fractures) have the lowest overall rate of neurological deficit (approximately 6%). When a deficit does occur, it is frequently an L5 nerve root injury caused by an associated L5 transverse process fracture impinging the root.
Question 1704
Topic: 6. Spine
A 34-year-old male sustains a severe pelvic crush injury. Radiographs and a CT scan reveal a sacral fracture extending medial to the sacral neuroforamina, involving the central sacral canal. According to the Denis classification, what is the approximate rate of neurologic deficit associated with this specific zone?
Correct Answer & Explanation
. Greater than 50%
Explanation
Denis Zone III fractures involve the central sacral canal and carry the highest rate of neurologic deficits, reported to be greater than 50% (typically 56-60%). These often present with bowel, bladder, or sexual dysfunction due to cauda equina injury.
Question 1705
Topic: 6. Spine
A 40-year-old male sustains a severe pelvic fracture with spino-pelvic dissociation. You plan to perform lumbopelvic fixation. Which biomechanical advantage does lumbopelvic fixation provide over standard iliosacral screws in this specific fracture pattern?
Correct Answer & Explanation
. It bypasses the fractured sacrum, transferring axial loads directly from the lumbar spine to the ilium.
Explanation
Lumbopelvic fixation utilizes pedicle screws in the lower lumbar spine connected to iliac screws. This construct completely bypasses the comminuted/dissociated sacrum, transferring axial loads directly from the spine to the intact ilium.
Question 1706
Topic: 6. Spine
A 32-year-old male sustains a severe crush injury to the pelvis. CT scan demonstrates a sacral fracture involving the central spinal canal. According to the Denis classification, what is the most likely neurologic deficit associated with this injury?
Correct Answer & Explanation
. Bowel, bladder, and sexual dysfunction
Explanation
Central sacral fractures (Denis Zone III) involve the spinal canal and carry a high risk (>50%) of bowel, bladder, and sexual dysfunction due to bilateral sacral root involvement.
Question 1707
Topic: 6. Spine
When placing an iliosacral screw into the S1 vertebral body, the pelvic outlet view is primarily used to evaluate which of the following?
Correct Answer & Explanation
. Screw penetration into the L5-S1 disc space and S1 foramen
Explanation
The pelvic outlet view provides a true AP of the sacrum, allowing the surgeon to assess the cephalad-caudad position of the screw to prevent breach into the L5-S1 disc space or the S1 neural foramen.
Question 1708
Topic: 6. Spine
A surgeon is performing an open reduction and sacral laminectomy for a patient with a Denis Zone III sacral fracture and cauda equina syndrome. During the posterior approach, the surgeon must be careful to avoid extensive lateral dissection past the sacral foramina primarily to prevent injury to which structures?
Correct Answer & Explanation
. Posterior rami of the sacral nerve roots
Explanation
During a posterior approach to the sacrum, lateral dissection must be limited to avoid injury to the posterior primary rami of the sacral nerve roots that exit the posterior neural foramina and supply the paraspinous muscles.
Question 1709
Topic: 6. Spine
A 72-year-old male presents with a 6-month history of bilateral lower extremity pain, numbness, and weakness that is consistently worse with prolonged standing and walking, and significantly relieved by sitting or leaning forward (the 'shopping cart sign'). Peripheral pulses are palpable and symmetric. Which of the following is the most definitive diagnostic characteristic of neurogenic claudication in this patient?
Correct Answer & Explanation
. Relief of symptoms by squatting or bending forward.
Explanation
Correct Answer: BThe most definitive characteristic distinguishing neurogenic claudication from vascular claudication is the relief of symptoms by squatting, sitting, or bending forward (flexion of the lumbar spine). This position increases the sagittal diameter of the spinal canal, reducing compression on the neural elements. Options A, D, and E are more typical of vascular claudication (fixed distance, bruits, worse with uphill walking due to increased calf muscle demand). Diminished peripheral pulses (Option C) are a sign of vascular disease, not neurogenic claudication.
Question 1710
Topic: 6. Spine
Which of the following physical examination findings is LEAST likely to be associated with typical degenerative lumbar spinal stenosis?
Correct Answer & Explanation
. Widespread upper motor neuron signs (e.g., hyperreflexia, spasticity).
Explanation
Correct Answer: CLumbar spinal stenosis primarily affects the cauda equina nerve roots, which are part of the peripheral nervous system. Therefore, it causes lower motor neuron signs (e.g., weakness, hyporeflexia, atrophy). Widespread upper motor neuron signs like hyperreflexia, spasticity, and a positive Babinski sign are characteristic of spinal cord myelopathy (which occurs above the conus medullaris, typically T12-L1 in adults) or brain lesions, and are NOT expected in isolated lumbar spinal stenosis. Options A, B, D, and E are all consistent with lumbar spinal stenosis (extension aggravates, normal ABI rules out vascular claudication, LMN signs are expected).
Question 1711
Topic: 6. Spine
A 65-year-old patient presents with classic symptoms of neurogenic claudication. What is the most appropriate initial imaging study to confirm the diagnosis and assess the severity of lumbar spinal stenosis?
Correct Answer & Explanation
. Magnetic Resonance Imaging (MRI) of the lumbar spine.
Explanation
Correct Answer: CMRI of the lumbar spine is the gold standard imaging study for diagnosing lumbar spinal stenosis. It provides excellent visualization of soft tissues, including the neural elements, ligamentum flavum, disc bulges, and allows for accurate assessment of the spinal canal and neural foramina narrowing. Plain radiographs (Option A) can show degenerative changes but not soft tissue compression. CT (Option B) is good for bone but inferior to MRI for neural structures unless MRI is contraindicated. EMG/NCS (Option D) and epidural injections (Option E) are diagnostic/therapeutic adjuncts, not primary imaging modalities for initial diagnosis.
Question 1712
Topic: 6. Spine
When differentiating neurogenic claudication from vascular claudication, which of the following statements is most accurate?
Correct Answer & Explanation
. Neurogenic claudication pain is generally exacerbated by standing still, whereas vascular claudication is not.
Explanation
Correct Answer: BNeurogenic claudication pain is characteristically exacerbated by lumbar extension (standing still or walking upright) and relieved by lumbar flexion (sitting, bending forward, leaning over a shopping cart). Vascular claudication is relieved by rest (not necessarily flexion) and exacerbated by activity. Absent pedal pulses (Option C) are a sign of vascular claudication. Option D is incorrect as both can vary. Option E is incorrect; walking uphill typically reduces lumbar lordosis, which can bemoretolerable for neurogenic claudication, while downhill walking (extension) is often worse.
Question 1713
Topic: 6. Spine
A 68-year-old female has mild to moderate lumbar spinal stenosis with neurogenic claudication symptoms. She has no significant neurological deficits. Which of the following conservative treatments has the strongest evidence base for initial management?
Correct Answer & Explanation
. Structured physical therapy emphasizing core strengthening and flexion exercises.
Explanation
Correct Answer: CStructured physical therapy, particularly focusing on core strengthening, flexibility, and flexion-based exercises, has the strongest evidence for initial conservative management of lumbar spinal stenosis. It aims to improve spinal mechanics, reduce pain, and improve walking tolerance. Opioids (Option A) are not recommended for long-term management due to dependency risks. Bed rest (Option B) is generally detrimental. While epidural steroid injections (Option D) can provide short-term relief, indefinite, frequent injections are not recommended due to potential side effects and diminishing returns. TENS (Option E) may offer symptomatic relief but is typically used as an adjunct, not as a standalone primary treatment.
Question 1714
Topic: 6. Spine
What is the primary indication for surgical intervention in patients with lumbar spinal stenosis?
Correct Answer & Explanation
. Failure of extensive conservative management to relieve debilitating symptoms.
Explanation
Correct Answer: BThe primary indication for surgical intervention in lumbar spinal stenosis is the failure of extensive conservative management (typically 3-6 months) to relieve debilitating symptoms that significantly impair a patient's quality of life. Radiographic stenosis alone (Option A) is not an indication. Patient request (Option C) without conservative trials is generally not appropriate. Mild symptoms (Option D) usually respond to conservative care. Disc degeneration (Option E) is a common finding but not an indication for surgery unless it contributes to instability or stenosis causing symptoms.
Question 1715
Topic: 6. Spine
Regarding lumbar laminectomy for spinal stenosis, what is the primary goal of the decompression?
Correct Answer & Explanation
. To directly relieve neural element compression by removing bone and soft tissue.
Explanation
Correct Answer: CThe primary goal of a lumbar laminectomy for spinal stenosis is direct decompression of the neural elements (cauda equina nerve roots). This involves removing hypertrophied ligamentum flavum, osteophytes, and sometimes portions of the lamina and facet joints to enlarge the spinal canal and neuroforamina, thereby alleviating compression. Stabilization (Option A), disc removal (Option B, though sometimes done concurrently for associated disc herniation, it's not the primary goal of laminectomy itself for stenosis), deformity correction (Option D), and preventing degeneration (Option E) are not the main objectives of a standalone decompression.
Question 1716
Topic: 6. Spine
In which of the following scenarios is adjunctive spinal fusion most strongly indicated alongside decompression for lumbar spinal stenosis?
Correct Answer & Explanation
. Concurrent degenerative spondylolisthesis (Grade I or II) with clinical or radiographic instability.
Explanation
Correct Answer: DAdjunctive fusion is most strongly indicated when there is significant preoperative instability or when decompression itself is likely to destabilize the segment. A concurrent degenerative spondylolisthesis (Grade I or II) with clinical instability (e.g., dynamic pain, progressive slip) or radiographic instability (increased translation or angulation on dynamic X-rays) is a common indication for fusion alongside decompression. Options A and B are typically treated with decompression alone. Multilevel stenosis (Option C) does not automatically require fusion unless instability is present. Prior microdiscectomy (Option E) doesn't inherently indicate fusion for stenosis unless instability or significant facetectomy is required for decompression.
Question 1717
Topic: 6. Spine
A patient presents with sudden onset of bilateral leg weakness, saddle anesthesia, and acute urinary retention. This constellation of symptoms most strongly suggests which of the following?
Correct Answer & Explanation
. Cauda Equina Syndrome.
Explanation
Correct Answer: DThe triad of bilateral lower extremity weakness, saddle anesthesia (sensory loss in the perineum, buttocks, and inner thighs), and urinary retention (or incontinence) is the classic presentation of Cauda Equina Syndrome (CES). CES is a surgical emergency requiring urgent decompression. Options A, B, C, and E do not typically present with this specific combination of severe, acute neurological deficits affecting bowel and bladder function.
Question 1718
Topic: 6. Spine
A 65-year-old diabetic male presents with insidious onset of back pain, low-grade fever, and progressive bilateral leg weakness over 2 weeks. On examination, he has a T10 sensory level and 3/5 motor strength in both lower extremities. Initial plain radiographs of the thoracic spine are unremarkable. Which of the following is the most appropriate initial diagnostic step?
Correct Answer & Explanation
. MRI of the thoracic spine with gadolinium
Explanation
Correct Answer: DMRI with gadolinium is the gold standard for diagnosing spinal epidural abscess (SEA), demonstrating the collection, degree of spinal cord compression, and identifying associated osteomyelitis or discitis. Given the progressive neurological deficit and suspicion of infection, urgent definitive imaging is crucial. Plain radiographs are insensitive in early disease. CT myelogram is less sensitive for soft tissue detail than MRI and involves radiation and contrast injection into the CSF. Lumbar puncture is generally contraindicated in suspected SEA due to the risk of neurological deterioration or meningitis. EMG is for peripheral nerve pathology. Corticosteroids are contraindicated before definitive diagnosis and debridement in bacterial infections.
Question 1719
Topic: 6. Spine
A patient undergoing hemodialysis develops severe cervical spine pain, fevers, and rapidly progressive quadriparesis. Blood cultures are pending. Given the patient's history, which organism is most likely responsible for a presumed spinal epidural abscess?
Correct Answer & Explanation
. Staphylococcus aureus (MRSA)
Explanation
Correct Answer: CStaphylococcus aureus is the most common pathogen responsible for spinal epidural abscesses (SEA), accounting for 60-90% of cases. Methicillin-resistant S. aureus (MRSA) is particularly prevalent in patients with healthcare-associated risk factors such as hemodialysis, IV drug use, recent surgery, or indwelling catheters. While E. coli and Pseudomonas can occur, and Candida in immunocompromised hosts, S. aureus remains the dominant pathogen, especially in the context of healthcare exposure. Mycobacterium tuberculosis typically presents with a more chronic course.
Question 1720
Topic: 6. Spine
A 70-year-old male with a known C6-C7 spinal epidural abscess presents with acute urinary retention and rapidly progressive weakness in his lower extremities (motor strength 2/5). He has been on intravenous antibiotics for 48 hours without clinical improvement. What is the most appropriate next step?
Correct Answer & Explanation
. Perform an urgent C6-C7 laminectomy and decompression
Explanation
Correct Answer: BUrgent surgical decompression is indicated for spinal epidural abscesses with progressive neurological deficits (such as new-onset urinary retention, rapidly worsening weakness) or failure of appropriate medical management to prevent irreversible neurological damage. Continuing antibiotics alone is insufficient. Adding rifampin may be part of an antibiotic strategy but does not address acute mechanical compression. Percutaneous aspiration may be considered for diagnosis or small, stable collections but not for acute, progressive deficits with neurological compromise. Steroids are generally contraindicated as they can mask symptoms, impair host immunity in bacterial infections, and are not a definitive treatment for pus collection.
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