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 7061
Topic: 6. Spine
A 45-year-old male with achondroplasia presents with progressive neurogenic claudication. The most common cause of lumbar spinal stenosis in this patient population is:
Correct Answer & Explanation
. Decreased interpedicular distance and shortened pedicles
Explanation
Achondroplasia features impaired endochondral ossification leading to congenitally short pedicles and progressively narrowing interpedicular distances from L1 to L5. This distinct anatomical variance is the primary structural cause of severe spinal stenosis in these patients.
Question 7062
Topic: 6. Spine
A patient with achondroplasia
requires spinal surgery for severe neurogenic claudication. What anatomical feature of the lumbar spine primarily contributes to this stenosis?
Correct Answer & Explanation
. Progressive decrease in interpedicular distance from L1 to L5
Explanation
Achondroplasia is characterized by congenitally short pedicles and a progressive decrease in the interpedicular distance from L1 to L5. This anatomical anomaly strongly predisposes these patients to severe, multi-level spinal stenosis.
Question 7063
Topic: 6. Spine
A 3-year-old child with achondroplasia presents with delayed motor milestones, hypotonia, and signs of central sleep apnea.
Which of the following is the most appropriate initial diagnostic imaging modality?
Correct Answer & Explanation
. Foramen magnum MRI
Explanation
Foramen magnum stenosis is a critical and potentially lethal complication in young children with achondroplasia, leading to cervicomedullary compression and central sleep apnea. MRI of the craniocervical junction is the gold standard imaging modality to evaluate this.
Question 7064
Topic: 6. Spine
An adult male with achondroplasia presents with bilateral leg heaviness, weakness, and progressive neurogenic claudication.
What is the primary anatomical etiology of his spinal stenosis?
Correct Answer & Explanation
. Shortened pedicles and decreased interpedicular distance
Explanation
Achondroplasia features a defect in endochondral ossification, leading to congenitally shortened pedicles and a narrowed spinal canal with a decreased interpedicular distance caudally. This predisposes these patients to severe, early-onset lumbar spinal stenosis.
Question 7065
Topic: 6. Spine
A 40-year-old male with achondroplasia presents with progressive neurogenic claudication. He is diagnosed with severe lumbar spinal stenosis. Which of the following anatomical anomalies is the primary contributor to his stenosis?
Correct Answer & Explanation
. Decreased interpedicular distance
Explanation
In achondroplasia, the pedicles are shortened and the interpedicular distance classically decreases from L1 to L5 (unlike the normal spine where it widens). This results in a congenitally narrow spinal canal and early-onset symptomatic spinal stenosis.
Question 7066
Topic: 6. Spine
A 4-year-old boy with a known skeletal dysplasia presents for a routine evaluation.
Given his condition (achondroplasia), radiographs of the lumbar spine are most likely to demonstrate which of the following characteristic findings?
Correct Answer & Explanation
. Decreasing interpedicular distance from L1 to L5
Explanation
In achondroplasia, the classic spinal radiographic finding is a narrowing (decreasing) of the interpedicular distance from L1 to L5. This predisposes patients to significant spinal stenosis later in life.
Question 7067
Topic: 6. Spine
A 5-year-old girl with normal intelligence, short-trunk dwarfism, and corneal clouding is diagnosed with Morquio syndrome (Mucopolysaccharidosis Type IV). Which orthopedic complication must be urgently screened for due to a high risk of catastrophic neurologic injury?
Correct Answer & Explanation
. Atlantoaxial instability
Explanation
Patients with Morquio syndrome are uniquely at high risk for atlantoaxial instability due to profound odontoid hypoplasia and ligamentous laxity. Screening cervical spine imaging is critical to prevent spinal cord compression.
Question 7068
Topic: 6. Spine
A 4-year-old boy with achondroplasia presents with lower extremity hyperreflexia, clumsiness, and central sleep apnea.
What is the most likely anatomic cause of these symptoms?
Correct Answer & Explanation
. Foramen magnum stenosis
Explanation
Foramen magnum stenosis is a critical and potentially lethal complication in infants and young children with achondroplasia. It presents with myelopathy (hyperreflexia, clonus), central sleep apnea, and respiratory difficulties, requiring urgent neurosurgical decompression.
Question 7069
Topic: 6. Spine
A 7-year-old boy complains of localized mid-back pain for several weeks. A lateral radiograph of the thoracic spine reveals a "vertebra plana" at T8 with preserved disc spaces. Laboratory studies are normal. Electron microscopy of a biopsy specimen from this lesion would most likely reveal which of the following structures?
Correct Answer & Explanation
. Birbeck granules
Explanation
The clinical picture of vertebra plana in a child is highly suspicious for Langerhans cell histiocytosis (eosinophilic granuloma). The pathognomonic electron microscopic finding for Langerhans cells is the presence of Birbeck granules, which are tennis-racket shaped cytoplasmic organelles.
Question 7070
Topic: 6. Spine
A 65-year-old male presents with chronic low back pain that significantly worsens with prolonged standing and walking, but improves with sitting or leaning forward (e.g., pushing a shopping cart). He describes bilateral leg pain and numbness that is relieved by rest. On examination, he has intact motor strength, normal reflexes, and no sensory deficits in a dermatomal pattern. Which of the following is the most likely diagnosis?
Correct Answer & Explanation
. Lumbar spinal stenosis
Explanation
The patient's classic presentation of neurogenic claudication, characterized by back and leg pain worsening with standing/walking and improving with sitting or leaning forward (the 'shopping cart sign'), is highly suggestive of lumbar spinal stenosis. This condition results from narrowing of the spinal canal, leading to compression of the neural elements. While spondylolisthesis can cause stenosis, the primary description points to the stenotic symptoms themselves. Lumbar disc herniation typically presents with more acute, radicular pain, often worsened with sitting and relieved by standing or walking short distances. Piriformis syndrome causes buttock pain with radiation down the leg, but less commonly presents with true neurogenic claudication relieved by leaning forward. A vertebral compression fracture would present with more acute, localized pain, often related to trauma or osteoporosis.
Question 7071
Topic: 6. Spine
A 32-year-old male competitive weightlifter complains of persistent, deep, aching low back pain that began subtly and gradually worsened over several months. The pain is exacerbated by lumbar extension and resisted hip flexion, and he reports a 'catch' when transitioning from flexion to extension. Physical examination reveals tenderness to palpation over the L5-S1 region and a positive single-leg hyperextension test (Stork test). Neurological examination is unremarkable. Which imaging study would be most appropriate for initial evaluation?
Correct Answer & Explanation
. Plain radiographs (AP, lateral, obliques) of the lumbar spine
Explanation
The patient's history (young athlete, extension-related pain, 'catch', tenderness over L5-S1, positive Stork test) is highly suggestive of spondylolysis, particularly a pars interarticularis defect. While MRI can visualize soft tissues well, plain radiographs including oblique views are the initial imaging of choice to diagnose spondylolysis by demonstrating the 'Scottie dog' collar defect in the pars interarticularis. If plain films are inconclusive or further characterization is needed, a CT scan might follow, especially for visualizing bone detail. MRI is excellent for disc and neural structures but less sensitive for early pars defects. A bone scan might be used to assess for active stress reaction in the pars, but radiographs are first-line for structural defects. EMG/NCS are for evaluating nerve impingement and are not indicated here as the neurological exam is unremarkable.
Question 7072
Topic: 6. Spine
A 70-year-old woman with a history of osteoporosis presents to the emergency department with severe, acute onset back pain after a minor fall. The pain is localized to the mid-thoracic region and worsens with movement, coughing, or sneezing. On examination, she has tenderness to palpation over the T8 spinous process and increased thoracic kyphosis. Neurological examination is normal. What is the most likely diagnosis?
Correct Answer & Explanation
. Vertebral compression fracture
Explanation
The acute onset of severe, localized thoracic back pain following a minor trauma in an elderly osteoporotic patient is classic for a vertebral compression fracture. The pain worsens with movement, coughing, or sneezing due to increased intra-abdominal pressure transmitted to the fractured vertebra. Increased thoracic kyphosis is a common sequela of multiple compression fractures. Lumbar disc herniation typically causes pain radiating to the leg. A spinal epidural abscess would present with fever, malaise, and rapidly progressive neurological deficits. Acute lumbar muscle strain is less likely to cause such severe, localized pain in the thoracic region after a fall, especially in an osteoporotic patient. While metastatic spinal tumors are a consideration in this age group, acute onset pain after minor trauma points more strongly to a fracture initially, though further workup may be warranted.
Question 7073
Topic: 6. Spine
A 45-year-old female presents with low back pain and unilateral leg pain extending below the knee. She reports numbness in the lateral aspect of her foot and weakness during ankle dorsiflexion. Her patellar reflex is normal, but the ankle jerk reflex is diminished. A positive straight leg raise test is elicited on the affected side. Based on these findings, which nerve root is most likely compressed?
Correct Answer & Explanation
. S1 nerve root
Explanation
The clinical presentation points to an S1 radiculopathy. Weakness in ankle dorsiflexion (primarily tibialis anterior) is L4/L5, but the combination with numbness in the lateral aspect of the foot (S1 dermatome) and a diminished ankle jerk reflex (S1 reflex) strongly points to S1 nerve root compression. L3 radiculopathy affects the knee jerk reflex and sensation over the medial thigh. L4 radiculopathy affects the patellar reflex and sensation over the medial leg. L5 radiculopathy affects great toe extension and sensation over the dorsum of the foot, but usually spares the ankle jerk reflex. The positive straight leg raise test is non-specific for the level but indicates nerve root irritation.
Question 7074
Topic: 6. Spine
A 55-year-old obese male presents with sudden onset, excruciating back pain radiating bilaterally into the buttocks and posterior thighs, associated with saddle anesthesia, bilateral lower extremity weakness, and difficulty initiating urination. What is the immediate management priority?
Correct Answer & Explanation
. Admit for immediate surgical decompression
Explanation
This patient's symptoms (saddle anesthesia, bilateral leg weakness, and bladder/bowel dysfunction, specifically difficulty with urination) are pathognomonic for cauda equina syndrome, a surgical emergency. The immediate management priority is to confirm the diagnosis with an emergent MRI of the lumbar spine and proceed with urgent surgical decompression to prevent permanent neurological deficits. Delay can lead to irreversible bladder, bowel, and sexual dysfunction, as well as motor and sensory loss. NSAIDs, muscle relaxants, physical therapy, and oral corticosteroids are inappropriate and would delay definitive treatment.
Question 7075
Topic: 6. Spine
Which of the following findings is most concerning for an underlying inflammatory (spondyloarthropathy) cause of chronic low back pain, rather than mechanical back pain?
Correct Answer & Explanation
. Pain improving with exercise and worse with rest/immobility
Explanation
Inflammatory back pain, characteristic of spondyloarthropathies (e.g., ankylosing spondylitis), typically improves with exercise and is worse with rest or immobility, particularly in the morning. The morning stiffness associated with inflammatory back pain often lasts longer than 30 minutes, sometimes several hours. Mechanical back pain, conversely, is usually exacerbated by activity and relieved by rest, has shorter morning stiffness, and commonly has onset in older individuals. Radicular symptoms can occur in both, but are not primarily indicative of inflammatory vs. mechanical origin. The cardinal features distinguishing inflammatory back pain include insidious onset, age of onset < 40 years, duration > 3 months, morning stiffness > 30 minutes, improvement with exercise, and not improving with rest.
Question 7076
Topic: 6. Spine
A 28-year-old nurse reports dull, aching low back pain that began insidiously and is worse after her shifts, especially when lifting patients. The pain is localized to the paraspinal muscles and occasionally radiates into the buttocks, but not down the leg. Neurological examination is entirely normal. She denies any 'red flag' symptoms. What is the most appropriate initial management?
Correct Answer & Explanation
. Recommend activity modification, NSAIDs, and physical therapy
Explanation
This presentation is highly consistent with acute or subacute mechanical low back pain, likely musculoligamentous strain. Given the absence of 'red flag' symptoms (fever, weight loss, neurological deficits, saddle anesthesia, bladder/bowel changes, history of cancer, severe nocturnal pain) and the typical nature of the pain (related to activity, localized), conservative management is the mainstay. This includes activity modification (avoiding exacerbating activities), non-steroidal anti-inflammatory drugs (NSAIDs) for pain relief, and physical therapy to improve core strength, flexibility, and body mechanics. Imaging like MRI is not indicated initially in the absence of red flags or persistent symptoms after a trial of conservative care. Oral steroids are not first-line for mechanical back pain. Urgent surgical consultation is for neurological emergencies or severe, refractory radiculopathy. A bone scan is not indicated without specific features suggesting stress fracture or tumor.
Question 7077
Topic: 6. Spine
Which of the following 'red flag' symptoms in a patient presenting with back pain necessitates immediate and thorough investigation?
Correct Answer & Explanation
. Unexplained weight loss or history of cancer
Explanation
Unexplained weight loss or a history of cancer are significant 'red flags' for serious underlying conditions such as metastatic disease, spinal tumors, or infection. These findings warrant immediate and thorough investigation, often including imaging (MRI or CT) and potentially blood tests. Pain radiating to the buttock is common in mechanical back pain and radiculopathy, not necessarily a red flag. Morning stiffness lasting 15 minutes is typical of mechanical back pain. Pain relief with rest is also characteristic of mechanical pain. Intermittent numbness in one leg, while concerning, is less immediately alarming than signs of systemic disease or malignancy, especially if not associated with progressive weakness or cauda equina symptoms.
Question 7078
Topic: 6. Spine
A 60-year-old male presents with worsening low back pain and progressive weakness in both lower extremities over the past 2 weeks. He reports difficulty walking and has noticed a change in his gait. Examination reveals hyperreflexia in the lower extremities, positive Babinski signs bilaterally, and diminished proprioception in the feet. Which of the following conditions is most likely?
Correct Answer & Explanation
. Cervical myelopathy
Explanation
The combination of progressive bilateral lower extremity weakness, hyperreflexia, positive Babinski signs, and gait disturbance points to an upper motor neuron lesion affecting the spinal cord. Given the back pain and lower extremity symptoms, a spinal cord compression (myelopathy) is the likely diagnosis. Spinal epidural abscess can cause myelopathy if high enough, but the most precise answer is myelopathy. Cervical myelopathy would involve upper extremity symptoms more prominently, although severe cervical myelopathy can cause only leg symptoms. Cauda equina syndrome is a lower motor neuron lesion, characterized by saddle anesthesia, flaccid weakness, diminished reflexes, and bladder/bowel dysfunction. Lumbar disc herniation with L5 radiculopathy is typically unilateral and causes lower motor neuron signs (flaccid weakness, hyporeflexia). Lumbar spinal stenosis can cause neurogenic claudication, but typically without upper motor neuron signs.
Question 7079
Topic: 6. Spine
Which characteristic is most indicative of a discogenic source of low back pain?
Correct Answer & Explanation
. Pain reproduced with sitting, forward flexion, and Valsalva maneuver
Explanation
Discogenic pain, particularly due to disc herniation, is often exacerbated by activities that increase intradiscal pressure or stretch the affected nerve root. These include sitting, forward flexion, and maneuvers like coughing, sneezing, or Valsalva, which increase intra-abdominal pressure and consequently epidural pressure. Pain worse with standing and walking and relieved with sitting is classic for spinal stenosis. Pain relieved by extension exercises is often associated with facet joint pathology. A positive femoral nerve stretch test suggests upper lumbar radiculopathy (L2, L3, L4). Nocturnal pain unrelated to position is a 'red flag' suggestive of tumor or infection.
Question 7080
Topic: 6. Spine
A 40-year-old patient presents with chronic low back pain. MRI reveals degenerative changes at L4-L5, including disc space narrowing, endplate sclerosis, and osteophytes. No significant neural compression is observed. Physical examination reveals localized tenderness over the L4-L5 facet joints, and pain is reproduced with extension and rotation of the lumbar spine. Which is the most appropriate initial intervention?
Correct Answer & Explanation
. Physical therapy focusing on core strengthening and flexibility
Explanation
The clinical presentation (chronic low back pain, tenderness over facet joints, pain with extension and rotation) and imaging findings (degenerative changes, no neural compression) are consistent with facet joint arthropathy. Initial management for facet pain typically begins with conservative measures. Physical therapy focusing on core strengthening, postural correction, and flexibility is a cornerstone of non-operative treatment for mechanical back pain, including facet arthropathy. Epidural steroid injections are more commonly used for radicular pain. Radiofrequency ablation may be considered if diagnostic facet injections provide temporary relief, indicating the facet joints are indeed the pain generators. Fusion surgery is a last resort for chronic, intractable pain, and not indicated without significant instability or neurological deficits. Long-term opioid therapy is generally discouraged due to risks of dependence and limited long-term efficacy.
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