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6. Spine MCQs

Practice Set 88 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 1741

Topic: Thoracolumbar Spine & Deformity

A 15-year-old boy presents with a 30-degree left thoracic scoliosis, severe localized back pain, and abnormal abdominal reflexes. His family history is negative for scoliosis. Based on the case information, which of these findings is considered an 'atypical feature' that warrants further investigation beyond standard scoliosis workup?

. The 30-degree curve magnitude, classifying it as moderate.
. The patient's male gender, as AIS is more common in females.
. The left thoracic curve, severe pain, and abnormal abdominal reflexes.
. The age of onset (adolescent), which is the most common presentation for idiopathic scoliosis.
. The absence of a family history of scoliosis.

Correct Answer & Explanation

. The left thoracic curve, severe pain, and abnormal abdominal reflexes.

Explanation

Correct Answer: CThe case states under 'Pattern recognition' that 'Atypical features indicate possible underlying pathology (e.g. left-sided curves, severe pain, rapid progression and short angular deformities.)' Additionally, under 'Neurological examination', it notes that 'abnormal abdominal reflexes are most commonly associated with intraspinal anomalies.' Therefore, the combination of a left thoracic curve, severe pain, and abnormal abdominal reflexes are all significant atypical features strongly suggesting an underlying intraspinal anomaly or other pathology, necessitating further investigation such as an MRI.Option A is incorrectbecause a 30-degree curve is moderate, but the magnitude itself is not an atypical feature that suggests underlying pathology. It's thecombinationof other factors that makes it atypical.Option B is incorrectbecause while AIS is more prevalent in females (5.4:1 for curves >20 degrees), male gender alone is not considered an 'atypical feature' indicating underlying pathology in the same way as a left-sided curve or severe pain. It simply means it's less common for males to develop AIS.Option D is incorrectbecause adolescent onset (10-maturity) is the most common age group for idiopathic scoliosis, so this is a typical, not atypical, feature.Option E is incorrectbecause while there is a genetic tendency for scoliosis (20% have an affected family member), the absence of a family history does not rule out idiopathic scoliosis and is not considered an 'atypical feature' indicating underlying pathology.

Question 1742

Topic: 6. Spine

A 37-year-old male presents to your clinic with a 3-week history of worsening low back pain radiating down his left leg. He describes the leg pain as burning, associated with numbness and tingling in his posterior calf and lateral foot. He denies any recent trauma. During your initial assessment, which of the following findings would be the most critical red flag to specifically rule out a serious spinal pathology like Cauda Equina Syndrome?

. A. Positive straight leg raise test at 30 degrees on the left.
. B. Subjective numbness in the S1 dermatome.
. C. Decreased ankle jerk reflex on the left side.
. D. New onset urinary retention and saddle area numbness.
. E. Pain predominating in the limb over the back.

Correct Answer & Explanation

. D. New onset urinary retention and saddle area numbness.

Explanation

Correct Answer: DThe case explicitly lists the characteristics of Cauda Equina Syndrome (CES) as urinary retention, faecal incontinence, saddle area numbness, loss of anal tone, and widespread neurological signs. These are considered red flags indicating a surgical emergency. While options A, B, C, and E are all consistent with a lumbar disc prolapse causing radiculopathy (specifically S1 in this case), they do not represent the acute, severe neurological compromise that defines CES. Early detection and intervention for CES are crucial for improving outcomes, making these symptoms the most critical to identify during the initial assessment.

Question 1743

Topic: 6. Spine

A 37-year-old male presents with back and left lower limb pain. An MRI scan is requested. Review the provided T2-weighted MRI images of the lumbar spine.

Based on the findings shown in the MRI, which nerve root is most likely compressed by the paracentral disc prolapse at the L5/S1 level?

. A. L4 nerve root
. B. L5 nerve root
. C. S1 nerve root
. D. S2 nerve root
. E. L3 nerve root

Correct Answer & Explanation

. C. S1 nerve root

Explanation

Correct Answer: CThe case states that the MRI shows a paracentral disc prolapse at the L5/S1 level. It further clarifies that for a lumbar disc prolapse, the 'traversing' nerve root is most commonly compressed by a common 'paracentral' disc prolapse. In the context of an L5/S1 disc prolapse, the S1 nerve root is the traversing nerve root at that level, making it the most likely to be compressed. The L5 nerve root would typically be affected by an L4/L5 disc prolapse, and the L4 nerve root by an L3/L4 disc prolapse.

Question 1744

Topic: 6. Spine

A 45-year-old patient presents with symptoms consistent with an L5 radiculopathy, including weakness in ankle dorsiflexion and numbness over the dorsum of the foot. An MRI reveals a paracentral disc prolapse. Based on the provided background knowledge regarding nerve root anatomy in the lumbar spine, at which intervertebral level would a paracentral disc prolapse most commonly cause an L5 radiculopathy?

. A. L3/L4
. B. L4/L5
. C. L5/S1
. D. S1/S2
. E. L2/L3

Correct Answer & Explanation

. B. L4/L5

Explanation

Correct Answer: BThe case explains the concept of traversing nerve roots in the lumbar spine: 'Thus an L4/5 disc prolapse commonly affects the L5 nerve root.' This is because the L4 nerve root has already exited the canal below the L4 pedicle, and it is the L5 'traversing' nerve root that is most commonly compressed by a paracentral disc prolapse at the L4/L5 interspace. An L5/S1 disc prolapse would typically affect the S1 nerve root, and an L3/L4 disc prolapse would typically affect the L4 nerve root.

Question 1745

Topic: 6. Spine

A 50-year-old male with a known history of lumbar disc herniation presents to the emergency department with acute onset bilateral leg weakness, urinary hesitancy, and saddle anesthesia. An MRI confirms a large central disc extrusion at L4/L5 compressing the cauda equina. What is the most appropriate immediate management for this patient?

. A. Initiate a 6-week course of physical therapy and NSAIDs.
. B. Schedule elective microdiscectomy within 3 months.
. C. Administer high-dose corticosteroids and observe for improvement.
. D. Urgent surgical decompression, ideally within 24 hours.
. E. Refer for pain management consultation and epidural injections.

Correct Answer & Explanation

. D. Urgent surgical decompression, ideally within 24 hours.

Explanation

Correct Answer: DThe patient's symptoms (bilateral leg weakness, urinary hesitancy, saddle anesthesia) are classic signs of Cauda Equina Syndrome (CES), which is confirmed by MRI. The case emphasizes the critical importance of early detection and intervention for CES, stating that 'early intervention (< 24 hours) has been shown to improve outcome.' Therefore, urgent surgical decompression is the most appropriate immediate management. Options A, B, C, and E represent conservative or delayed approaches that are inappropriate for a neurological emergency like CES.

Question 1746

Topic: 6. Spine

A patient presents with C7 radiculopathy symptoms, including weakness in triceps extension and numbness along the middle finger. Based on the background knowledge provided regarding nerve root anatomy in the cervical spine, which cervical disc level is most commonly associated with a C7 radiculopathy due to a prolapsed disc?

. A. C4/C5
. B. C5/C6
. C. C6/C7
. D. C7/T1
. E. C3/C4

Correct Answer & Explanation

. C. C6/C7

Explanation

Correct Answer: CThe case explains the unique nomenclature in the cervical spine: 'Because the C6 nerve root exits above (not below) the C6 vertebra this double change means a prolapsed cervical disc at the C5/C6 level most commonly affects the C6 nerve root.' Following this pattern, a disc prolapse at the C6/C7 level would most commonly affect the C7 nerve root, as the C7 nerve root exits above the C7 vertebra. Therefore, C6/C7 is the level most commonly associated with C7 radiculopathy.

Question 1747

Topic: 6. Spine

A 60-year-old patient presents with progressive gait disturbance, bilateral leg spasticity, and mid-thoracic back pain. Imaging reveals a calcified disc herniation at T8/T9. Based on the background knowledge provided, what is the most likely diagnosis and the appropriate surgical approach?

. A. Lumbar disc prolapse; posterior microdiscectomy.
. B. Cervical myelopathy; anterior cervical discectomy and fusion.
. C. Thoracic disc prolapse; anterior decompression via thoracotomy and partial vertebrectomy.
. D. Cauda equina syndrome; urgent posterior laminectomy.
. E. Spinal tumor; posterior spinal fusion.

Correct Answer & Explanation

. C. Thoracic disc prolapse; anterior decompression via thoracotomy and partial vertebrectomy.

Explanation

Correct Answer: CThe case specifically describes thoracic disc prolapse as rare, typically presenting with symptoms and signs of spinal cord compression associated with thoracic back pain. It also notes that 'The discs are usually calcified and require decompression from the front. Treatment therefore is via a thoracotomy and partial vertebrectomy.' The patient's symptoms (gait disturbance, leg spasticity, mid-thoracic back pain) and the finding of a calcified disc herniation are consistent with a thoracic disc prolapse requiring an anterior approach.

Question 1748

Topic: 6. Spine

An MRI report describes a lumbar disc herniation where the disc material has a narrow 'neck' at its base but remains continuous with the parent disc. According to the nomenclature described in the case, how would this type of disc herniation be classified?

. A. Broad-based protrusion
. B. Focal protrusion
. C. Extrusion
. D. Sequestration
. E. Symmetrical herniation

Correct Answer & Explanation

. C. Extrusion

Explanation

Correct Answer: CThe case defines disc nomenclature, stating: 'A focal disc herniation may be described as a protrusion or extrusion. An extruded disc has a narrow โ€˜neckโ€™ at its base.' The description of a narrow neck at its base while remaining continuous with the parent disc perfectly matches the definition of an extrusion. A sequestration would imply the material is no longer in continuity with the disc.

Question 1749

Topic: 6. Spine

The 37-year-old male from the initial case, with an L5/S1 paracentral disc prolapse causing S1 radiculopathy, has been undergoing conservative management for 8 weeks. He reports only minimal improvement in his pain and neurological symptoms. He has no red flag symptoms of Cauda Equina Syndrome. What is the most appropriate next step in management for this patient?

. A. Continue conservative management for another 4-8 weeks.
. B. Immediately proceed with microdiscectomy.
. C. Prescribe a stronger opioid regimen.
. D. Order repeat MRI to assess for disc regression.
. E. Refer for spinal cord stimulator evaluation.

Correct Answer & Explanation

. A. Continue conservative management for another 4-8 weeks.

Explanation

Correct Answer: AThe case states the initial treatment for lumbar disc prolapse is conservative, as 'the natural history of most lumbar disc prolapses is that they resolve with time.' It further advises: 'If it has not resolved after 6โ€“12 weeks of conservative management I would offer the patient microdiscectomy.' Since the patient is at 8 weeks with only minimal improvement and no red flags, continuing conservative management for the full 6-12 week period (i.e., another 4 weeks or more) is the most appropriate next step before considering surgical intervention. Immediate microdiscectomy (Option B) is premature, and options C, D, and E are not the primary next steps based on the provided treatment algorithm.

Question 1750

Topic: 6. Spine

A 35-year-old male presents with 6 weeks of severe right-sided leg pain radiating to the lateral border of his foot. Exam reveals an absent Achilles reflex and 4/5 plantar flexion. MRI shows a large paracentral disc extrusion at L5-S1. What is the most likely natural history if managed non-operatively?

. Progressive motor deficit requiring eventual arthrodesis
. Spontaneous resorption of the extruded disc fragment with clinical improvement
. Ossification of the posterior longitudinal ligament
. Development of cauda equina syndrome
. Chronic intractable pain with no change in disc size

Correct Answer & Explanation

. Spontaneous resorption of the extruded disc fragment with clinical improvement

Explanation

Large, extruded, or sequestered disc herniations have a high rate of spontaneous resorption via macrophage phagocytosis. Non-operative management is highly successful for L5-S1 radiculopathy without progressive or severe neurological deficits.

Question 1751

Topic: 6. Spine

A 45-year-old female presents with neck pain and right arm numbness. Physical examination reveals weakness in wrist extension, a diminished brachioradialis reflex, and decreased sensation over the dorsal web space of the thumb and index finger. A disc herniation at which of the following cervical levels is most likely responsible?

. C4-C5
. C5-C6
. C6-C7
. C7-T1
. C3-C4

Correct Answer & Explanation

. C5-C6

Explanation

The patient exhibits signs of a C6 radiculopathy (wrist extension weakness, decreased brachioradialis reflex, numbness in thumb/index finger). In the cervical spine, the exiting nerve root corresponds to the lower vertebral level of the disc space, so a C5-C6 disc herniation compresses the C6 root.

Question 1752

Topic: 6. Spine

A 50-year-old male presents with left anterior thigh pain and weakness in knee extension. Physical examination reveals a diminished patellar reflex. MRI demonstrates a far lateral (extraforaminal) disc herniation at L4-L5. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at that level. Therefore, an L4-L5 far lateral disc herniation compresses the L4 nerve root, leading to anterior thigh pain, quadriceps weakness, and a decreased patellar reflex.

Question 1753

Topic: 6. Spine

A 14-year-old male with a history of Duchenne muscular dystrophy presents with a progressive scoliosis measuring 48 degrees. His forced vital capacity (FVC) is currently 45% of predicted. What is the most appropriate management?

. TLSO brace for 23 hours a day
. Observation until the curve reaches 60 degrees
. Posterior spinal fusion to the pelvis
. Serial casting
. Anterior spinal fusion

Correct Answer & Explanation

. Posterior spinal fusion to the pelvis

Explanation

In Duchenne muscular dystrophy, scoliosis progresses relentlessly and bracing is ineffective. Surgery is indicated when the curve exceeds 20-30 degrees and should be performed before the FVC drops below 30-35% due to high perioperative pulmonary risks. Fusion typically extends to the pelvis.

Question 1754

Topic: 6. Spine

A 16-year-old female undergoes posterior spinal fusion for AIS. On post-operative day 4, she develops severe epigastric pain, bilious vomiting, and abdominal distension. Which of the following is the most likely underlying anatomic cause of this complication?

. Compression of the duodenum by the superior mesenteric artery
. Bowel obstruction secondary to opioid-induced ileus
. Gastric volvulus from altered spinal alignment
. Cholecystitis due to prolonged fasting
. Pancreatitis from intraoperative hypotension

Correct Answer & Explanation

. Compression of the duodenum by the superior mesenteric artery

Explanation

Superior mesenteric artery (SMA) syndrome, also known as cast syndrome, can occur after surgical correction of scoliosis. The acute lengthening of the spine stretches the SMA, decreasing the aortomesenteric angle and compressing the third portion of the duodenum.

Question 1755

Topic: 6. Spine

A 65-year-old male with a history of chronic low back pain presents with neurogenic claudication. He reports his leg pain improves when leaning forward on a shopping cart. MRI shows severe central canal stenosis at L4-L5. According to the SPORT trial results for spinal stenosis, what is the expected outcome of surgical decompression compared to non-operative treatment?

. Surgery shows no significant difference in pain relief at 1 year in the as-treated analysis.
. Surgery provides significantly greater improvement in pain and function at 4 years in the as-treated analysis.
. Non-operative treatment has a higher rate of neurological complication at 5 years.
. Surgery is associated with a high rate of adjacent segment disease requiring revision within 2 years.
. There is no difference in walking distance between the two groups at 3 months.

Correct Answer & Explanation

. Surgery provides significantly greater improvement in pain and function at 4 years in the as-treated analysis.

Explanation

The Spine Patient Outcomes Research Trial (SPORT) demonstrated that patients surgically treated for lumbar spinal stenosis experienced significantly greater improvement in pain, function, and satisfaction compared to those treated non-operatively, particularly in the as-treated analysis.

Question 1756

Topic: 6. Spine

A 4-year-old child presents with a progressive left thoracic scoliosis of 35 degrees. MRI of the neuroaxis reveals a Chiari I malformation and a syrinx spanning T3-T9. What is the most appropriate initial management?

. Bracing with a Milwaukee brace
. Posterior spinal fusion from T2 to T10
. Neurosurgical decompression of the foramen magnum
. VEPTR (Vertical Expandable Prosthetic Titanium Rib) insertion
. Observation with repeat MRI in 1 year

Correct Answer & Explanation

. Neurosurgical decompression of the foramen magnum

Explanation

In atypical or juvenile scoliosis associated with a symptomatic Chiari malformation and syrinx, neurosurgical decompression (suboccipital decompression) is the primary initial treatment. Spine deformity often stabilizes or improves after addressing the underlying neuroaxis abnormality.

Question 1757

Topic: 6. Spine

A 55-year-old female presents with neck pain and clumsiness in her hands. She notes difficulty buttoning her shirts and frequent tripping. Exam shows hyperreflexia in both lower extremities, a positive Hoffmann's sign, and sustained ankle clonus. What is the most appropriate diagnostic imaging step?

. CT myelogram of the cervical spine
. MRI of the brain
. Electromyography (EMG) of the upper and lower extremities
. MRI of the cervical spine without contrast
. Standing full-length scoliosis radiographs

Correct Answer & Explanation

. MRI of the cervical spine without contrast

Explanation

The patient exhibits classic signs of cervical myelopathy (hand clumsiness, gait instability, upper motor neuron signs). MRI of the cervical spine without contrast is the gold standard imaging modality to evaluate for spinal cord compression and myelomalacia.

Question 1758

Topic: Cervical Spine

During an anterior cervical discectomy and fusion (ACDF) via a right-sided approach, the surgeon carefully mobilizes the midline structures. Which of the following nerves is at higher risk of injury during a right-sided lower cervical approach compared to a left-sided approach?

. Superior laryngeal nerve
. Recurrent laryngeal nerve
. Hypoglossal nerve
. Glossopharyngeal nerve
. Phrenic nerve

Correct Answer & Explanation

. Recurrent laryngeal nerve

Explanation

The recurrent laryngeal nerve is at higher risk during a right-sided approach to the lower cervical spine because its course is more variable and it passes obliquely from lateral to medial. On the left side, it travels vertically within the tracheoesophageal groove, making it more predictable and protected.

Question 1759

Topic: 6. Spine

A 25-year-old male sustains an acute paracentral disc herniation at L4-L5 resulting in an L5 radiculopathy. He has failed 6 weeks of physical therapy and NSAIDs. Which of the following physical exam findings is most specific for an L5 nerve root compression?

. Weakness in ankle plantarflexion
. Diminished Achilles reflex
. Weakness in extensor hallucis longus (EHL)
. Decreased sensation over the medial malleolus
. Positive femoral nerve stretch test

Correct Answer & Explanation

. Weakness in extensor hallucis longus (EHL)

Explanation

L5 radiculopathy classically presents with weakness in the extensor hallucis longus (EHL) and diminished sensation over the dorsal web space between the first and second toes. Plantarflexion and the Achilles reflex are predominantly S1, while the medial malleolus is L4.

Question 1760

Topic: 6. Spine

A 45-year-old male presents with right leg pain radiating to the dorsum of the foot and new-onset weakness in great toe extension. MRI demonstrates a posterolateral disc herniation at L4-L5. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L5

Explanation

In the lumbar spine, a posterolateral disc herniation typically compresses the traversing nerve root. At the L4-L5 level, this is the L5 nerve root, which presents clinically with weakness in the extensor hallucis longus and altered sensation over the dorsal foot.

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