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6. Spine MCQs

Practice Set 81 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 1601

Topic: 6. Spine

A 68-year-old male with a history of hypertension and diabetes presents with progressively worsening low back pain and L4-L5 neurogenic claudication. He has a Grade I degenerative spondylolisthesis at L4-L5. His pain is 7/10 on the VAS. He has tried epidural steroid injections, NSAIDs, and physical therapy for 9 months with no sustained relief. What is the strongest indicator for surgical intervention in this patient?

. Presence of a Grade I slip
. Age of the patient
. Failure of extensive conservative management and persistent severe symptoms
. History of hypertension and diabetes
. Neurogenic claudication

Correct Answer & Explanation

. Failure of extensive conservative management and persistent severe symptoms

Explanation

Correct Answer: CThe strongest indicator for surgical intervention in symptomatic degenerative spondylolisthesis is the failure of a prolonged course of conservative management combined with persistent severe symptoms (pain, neurological deficits) impacting quality of life. While neurogenic claudication itself is a symptom, its persistence despite non-operative efforts is the key factor. The grade of slip alone isn't an indication for surgery, nor are comorbidities unless they contraindicate surgery. Age is a factor for surgical risk but not an indication for surgery.

Question 1602

Topic: 6. Spine

A 37-year-old male presents with back and left lower limb pain, suspected 'slipped disc'. During the initial evaluation, which of the following findings would be the MOST concerning red flag, necessitating immediate further investigation for a serious spinal pathology?

. Burning dermatomal pain predominating over back pain.
. Decreased ankle jerk reflex on the affected side.
. Subjective numbness and paraesthesia in the S1 distribution.
. Acute onset of urinary retention and saddle anesthesia.
. Positive straight leg raise test at 45 degrees.

Correct Answer & Explanation

. Acute onset of urinary retention and saddle anesthesia.

Explanation

Correct Answer: DThe case explicitly lists 'Urinary retention', 'Faecal incontinence', 'Saddle area numbness and loss of anal tone', and 'Widespread neurological signs' as characteristics of Cauda Equina Syndrome (CES). The importance of detecting CES early is highlighted, with early intervention (< 24 hours) shown to improve outcome. Acute onset of urinary retention and saddle anesthesia are hallmark symptoms of CES, representing a surgical emergency requiring immediate investigation and intervention. Options A, B, C, and E are typical signs and symptoms of radiculopathy, which, while requiring appropriate management, do not represent the same level of immediate neurological emergency as CES.

Question 1603

Topic: 6. Spine

A 37-year-old male presents with left lower limb radiculopathy. An MRI is performed. Review the provided T2-weighted MRI scan of the lumbar spine.

Based on the image and the case description, what is the most likely diagnosis and affected nerve root?

. L4/L5 central disc protrusion affecting the L4 nerve root.
. L5/S1 far lateral disc extrusion affecting the L5 nerve root.
. L5/S1 paracentral disc prolapse affecting the S1 nerve root.
. L4/L5 broad-based disc herniation affecting the L5 nerve root.
. S1/S2 central disc sequestration affecting the S2 nerve root.

Correct Answer & Explanation

. L5/S1 paracentral disc prolapse affecting the S1 nerve root.

Explanation

Correct Answer: CThe case explicitly states that the MRI shows 'a paracentral disc prolapse at the L5/S1 level'. The background knowledge section on 'Exiting nerve roots in the cervical and lumbar spine' further clarifies that for a common 'paracentral' disc prolapse at the L5/S1 level, it is the S1 'traversing' nerve root that is most commonly compressed. Therefore, an L5/S1 paracentral disc prolapse affecting the S1 nerve root is the most accurate diagnosis based on the provided information.

Question 1604

Topic: 6. Spine

A 45-year-old patient presents with acute low back pain and bilateral leg weakness. To definitively diagnose Cauda Equina Syndrome, which of the following clinical findings is considered a hallmark symptom?

. Severe, radiating leg pain below the knee.
. Positive straight leg raise test bilaterally.
. Progressive motor weakness in a single dermatome.
. New onset urinary retention or overflow incontinence.
. Diminished deep tendon reflexes in both lower extremities.

Correct Answer & Explanation

. New onset urinary retention or overflow incontinence.

Explanation

Correct Answer: DThe case explicitly lists 'Urinary retention' and 'Faecal incontinence' as key characteristics of Cauda Equina Syndrome. These symptoms, along with saddle area numbness and loss of anal tone, are considered hallmark signs of CES, indicating significant compression of the sacral nerve roots. While options A, B, C, and E can be present in various spinal pathologies, including severe radiculopathy, new onset urinary retention or overflow incontinence is a critical red flag that mandates immediate investigation for CES.

Question 1605

Topic: 6. Spine

A 50-year-old patient presents with a 12-hour history of saddle anesthesia, new-onset urinary retention, and progressive bilateral lower extremity weakness. An MRI confirms a large acute disc prolapse causing Cauda Equina Syndrome. What is the most appropriate immediate management strategy?

. Initiate a 6-week course of oral corticosteroids and physical therapy.
. Schedule elective microdiscectomy within 3 months if symptoms persist.
. Urgent surgical decompression within 24 hours.
. Refer for epidural steroid injections and pain management.
. Observe for spontaneous resolution over 72 hours with bed rest.

Correct Answer & Explanation

. Urgent surgical decompression within 24 hours.

Explanation

Correct Answer: CThe case emphasizes the critical importance of timely intervention for Cauda Equina Syndrome, stating: 'The importance of detecting cauda equina syndrome early is that early intervention (< 24 hours) has been shown to improve outcome.' Given the acute onset of hallmark CES symptoms (saddle anesthesia, urinary retention, bilateral weakness) and MRI confirmation, urgent surgical decompression is indicated to prevent permanent neurological deficits. Options A, B, D, and E represent conservative or delayed management strategies that are inappropriate and potentially harmful in the setting of acute CES.

Question 1606

Topic: 6. Spine

A 62-year-old patient presents with symptoms consistent with an L4/L5 paracentral disc prolapse. Based on the typical anatomical relationships described in the case, which nerve root is most commonly affected by this type of disc herniation?

. L3 exiting nerve root.
. L4 exiting nerve root.
. L5 traversing nerve root.
. S1 traversing nerve root.
. L4 dorsal root ganglion.

Correct Answer & Explanation

. L5 traversing nerve root.

Explanation

Correct Answer: CThe 'Exiting nerve roots in the cervical and lumbar spine' section explicitly clarifies the anatomical relationship: 'The knowledge that the L4 nerve root exits the spinal canal below the L4 pedicle may (incorrectly) lead the candidate to expect the L4 nerve root to be compressed when a disc prolapse occurs below the L4 vertebra in the L4/5 interspace. It is best to think of this nerve root as ‘already having left the canal’ and therefore it is the L5 ‘traversing’ nerve root that is most commonly compressed by the common ‘paracentral’ disc prolapse. ... Thus an L4/5 disc prolapse commonly affects the L5 nerve root.'

Question 1607

Topic: 6. Spine

A 48-year-old patient presents with right arm pain and weakness. MRI reveals a disc prolapse at the C5/C6 level. According to the anatomical principles outlined in the case, which nerve root is most likely compressed?

. C4 nerve root.
. C5 nerve root.
. C6 nerve root.
. C7 nerve root.
. C8 nerve root.

Correct Answer & Explanation

. C6 nerve root.

Explanation

Correct Answer: CThe 'Exiting nerve roots in the cervical and lumbar spine' section details the unique nomenclature in the cervical spine: 'In the cervical spine, a prolapsed disc typically affects the exiting nerve root at that level (there is no traversing nerve root because the roots leave the spinal cord and exit the canal almost horizontally). But there is a nomenclature change 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.'

Question 1608

Topic: 6. Spine

A patient's MRI report describes a disc herniation where the displaced disc material has a narrow 'neck' at its base but remains in continuity with the parent disc. According to the nomenclature provided, how would this specific type of disc herniation be classified?

. Broad-based protrusion.
. Symmetrical bulge.
. Extrusion.
. Sequestration.
. Focal protrusion.

Correct Answer & Explanation

. Extrusion.

Explanation

Correct Answer: CThe 'Nomenclature' section defines different types of disc herniation. It states: 'A focal disc herniation may be described as a protrusion or extrusion. An extruded disc has a narrow ‘neck’ at its base. Extruded disc material is sequestrated if it is no longer in continuity with the disc.' The description in the question, 'displaced disc material has a narrow 'neck' at its base but remains in continuity with the parent disc,' perfectly matches the definition of an extrusion.

Question 1609

Topic: 6. Spine

A 55-year-old patient presents with progressive upper extremity weakness, gait disturbance, and thoracic back pain. MRI reveals a calcified thoracic disc prolapse at T8/T9 causing spinal cord compression. Based on the case information, what is the recommended surgical approach for this condition?

. Posterior laminectomy and discectomy.
. Anterior cervical discectomy and fusion.
. Thoracotomy and partial vertebrectomy.
. Lumbar microdiscectomy.
. Percutaneous endoscopic discectomy.

Correct Answer & Explanation

. Thoracotomy and partial vertebrectomy.

Explanation

Correct Answer: CThe 'Disc prolapse background knowledge' section specifically addresses thoracic disc prolapse: 'A thoracic disc prolapse (rare) will typically present with symptoms and signs of spinal cord compression associated with thoracic back pain... The discs are usually calcified and require decompression from the front. Treatment therefore is via a thoracotomy and partial vertebrectomy.' This indicates that an anterior approach via thoracotomy and partial vertebrectomy is the standard surgical treatment for thoracic disc prolapse causing spinal cord compression.

Question 1610

Topic: 6. Spine

A 37-year-old male with a left L5/S1 paracentral disc prolapse causing S1 radiculopathy has been managed conservatively for 8 weeks with physical therapy and NSAIDs. His symptoms have shown minimal improvement, and he continues to experience significant pain and functional limitation. What is the most appropriate next step in his management?

. Continue conservative management for another 6 months, as most resolve spontaneously.
. Offer immediate microdiscectomy.
. Prescribe a stronger opioid regimen and recommend bed rest.
. Refer for a repeat MRI to assess for disc re-herniation.
. Initiate a trial of epidural steroid injections before considering surgery.

Correct Answer & Explanation

. Offer immediate microdiscectomy.

Explanation

Correct Answer: BThe candidate's proposed treatment plan for a lumbar disc prolapse states: 'Initially conservatively as the natural history of most lumbar disc prolapses is that they resolve with time. If it has not resolved after 6–12 weeks of conservative management I would offer the patient microdiscectomy.' Given that the patient has undergone 8 weeks of conservative management with minimal improvement, he falls within the 6-12 week window where surgical intervention (microdiscectomy) would be offered. While epidural steroid injections (Option E) are a common non-surgical intervention, the case specifically outlines microdiscectomy as the next step after 6-12 weeks of failed conservative management. Continuing conservative management for another 6 months (Option A) would be excessively prolonged given the persistent symptoms. Options C and D are not the primary next steps in this scenario.

Question 1611

Topic: 6. Spine

A 45-year-old male presents with acute back pain, bilateral leg radiculopathy, and urinary difficulties. Post-void residual (PVR) volume is measured via ultrasound. What PVR value is generally accepted as the threshold with the highest specificity to prompt urgent MRI for suspected cauda equina syndrome?

. 50 mL
. 100 mL
. 200 mL
. 500 mL
. 1000 mL

Correct Answer & Explanation

. 200 mL

Explanation

A post-void residual (PVR) > 200 mL is highly suggestive of urinary retention associated with cauda equina syndrome and warrants urgent MRI. A PVR < 100 mL makes the diagnosis highly unlikely.

Question 1612

Topic: 6. Spine

A 50-year-old male presents with acute onset right anterior thigh pain and weakness in knee extension. An MRI of the lumbar spine reveals a far lateral disc herniation at L4-L5. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, far lateral (extraforaminal) disc herniations compress the exiting nerve root at that level. Therefore, an L4-L5 far lateral herniation compresses the L4 nerve root.

Question 1613

Topic: Thoracolumbar Spine & Deformity

A 62-year-old female presents with neurogenic claudication. Radiographs demonstrate an L4-L5 Grade I degenerative spondylolisthesis. Which of the following anatomic characteristics is most strongly associated with the development of this condition?

. Coronal orientation of the L4-L5 facet joints
. Sagittal orientation of the L4-L5 facet joints
. Decreased pelvic incidence
. Decreased lumbar lordosis
. A pre-existing defect in the pars interarticularis

Correct Answer & Explanation

. Sagittal orientation of the L4-L5 facet joints

Explanation

Sagittal orientation of the facet joints is a major anatomic risk factor for degenerative spondylolisthesis, as it provides less resistance to anterior shear forces. Increased pelvic incidence and female sex are also well-documented risk factors.

Question 1614

Topic: Thoracolumbar Spine & Deformity

An 11-year-old girl is diagnosed with a high-grade dysplastic spondylolisthesis at L5-S1. Which of the following radiographic parameters is the most reliable predictor for further slip progression?

. Sacral slope
. Pelvic tilt
. Slip angle
. Lumbar lordosis
. Intervertebral disc height

Correct Answer & Explanation

. Slip angle

Explanation

A high slip angle (typically > 45-50 degrees) is the most predictive radiographic parameter for the progression of a high-grade spondylolisthesis. It reflects the local kyphosis at the lumbosacral junction.

Question 1615

Topic: 6. Spine

A 35-year-old male is referred after a lumbar MRI, obtained for an isolated and self-limiting episode of back pain 3 months ago, revealed a large right-sided L5-S1 paracentral disc herniation. The patient is currently completely asymptomatic with normal strength, sensation, and reflexes. What is the most appropriate next step in management?

. L5-S1 microdiscectomy
. Lumbosacral epidural steroid injection
. Six weeks of physical therapy
. Observation
. Electromyography (EMG) of the lower extremities

Correct Answer & Explanation

. Observation

Explanation

The patient is entirely asymptomatic despite the persistent MRI findings. Observation is the standard of care, as up to 90% of asymptomatic or mildly symptomatic disc herniations will resorb or remain clinically silent without surgical intervention.

Question 1616

Topic: 6. Spine

A 16-year-old male presents with severe lower back pain and an L5-S1 Grade IV isthmic spondylolisthesis. During a surgical reduction and fusion, which neurologic structure is at the highest risk of stretch injury?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. Cauda equina

Correct Answer & Explanation

. L5 nerve root

Explanation

The L5 nerve root is at the highest risk of stretch injury during the reduction of a high-grade L5-S1 spondylolisthesis. For this reason, many surgeons advocate for in situ fusion or only partial reduction to minimize neurologic complications.

Question 1617

Topic: 6. Spine

A 48-year-old male presents with new-onset saddle anesthesia, bilateral lower extremity weakness, and urinary incontinence that began 12 hours ago. He is diagnosed with cauda equina syndrome. For the highest likelihood of significant bladder function recovery, decompression should ideally be performed within what timeframe from symptom onset?

. 12 hours
. 24 hours
. 48 hours
. 72 hours
. 96 hours

Correct Answer & Explanation

. 48 hours

Explanation

Literature strongly supports surgical decompression within 48 hours of symptom onset in cauda equina syndrome to maximize the recovery of motor, sensory, and sphincter function. Delays beyond 48 hours are associated with significantly poorer urologic outcomes.

Question 1618

Topic: 6. Spine
A 35-year-old female presents with saddle anesthesia, bilateral leg weakness, and urinary incontinence. On examination, she exhibits hyperreflexia in the patellar and Achilles tendons, a positive Babinski sign bilaterally, and decreased anal sphincter tone. Which of the following is the most likely diagnosis?
. Cauda equina syndrome
. Conus medullaris syndrome
. Guillain-Barré syndrome
. Lumbar spinal stenosis
. Far lateral disc herniation

Correct Answer & Explanation

. Conus medullaris syndrome

Explanation

Conus medullaris syndrome presents with a combination of upper motor neuron (UMN) signs (hyperreflexia, Babinski) and lower motor neuron signs, along with early bowel/bladder dysfunction. Cauda equina syndrome is strictly a lower motor neuron lesion without UMN signs.

Question 1619

Topic: 6. Spine
A 42-year-old man presents with acute onset of bilateral lower extremity weakness, saddle anesthesia, and urinary retention following a heavy lifting injury. A post-void residual volume is >300 mL. MRI confirms a massive central L4-L5 disc extrusion compressing the cauda equina. Which of the following is the single most important prognostic factor for the return of his normal bowel and bladder function following emergent decompression?
. Timing of surgical decompression less than 12 hours from symptom onset
. The degree of pre-operative perineal sensory loss
. The patient's pre-operative level of urinary sphincter dysfunction
. The axial cross-sectional area of the disc herniation
. Administration of high-dose corticosteroids prior to surgery

Correct Answer & Explanation

. The patient's pre-operative level of urinary sphincter dysfunction

Explanation

The most significant prognostic factor for functional recovery in Cauda Equina Syndrome (CES) is the degree of neurological impairment, specifically urinary dysfunction, at the time of surgery. Patients with incomplete CES (CES-I) have a much higher likelihood of full recovery than those with complete CES (CES-R) characterized by painless urinary retention.

Question 1620

Topic: Thoracolumbar Spine & Deformity

A 16-year-old male with a high-grade L5-S1 isthmic spondylolisthesis is evaluated for surgical intervention. Radiographic assessment reveals a high pelvic incidence (PI). Which of the following accurately describes the relationship between pelvic incidence and high-grade spondylolisthesis?

. Pelvic incidence decreases as the severity of the slip increases.
. High pelvic incidence implies a more vertical sacrum, increasing shear forces.
. Pelvic incidence is a dynamic parameter that normalizes after successful in situ fusion.
. High pelvic incidence correlates with increased sacral slope and higher shear forces at the lumbosacral junction.
. Pelvic incidence has no established correlation with the risk of slip progression.

Correct Answer & Explanation

. High pelvic incidence correlates with increased sacral slope and higher shear forces at the lumbosacral junction.

Explanation

Pelvic incidence (PI) is a fixed morphologic parameter (PI = Pelvic Tilt + Sacral Slope). High PI is strongly associated with high-grade isthmic spondylolisthesis because it results in a higher sacral slope, which increases the anterior shear forces across the L5-S1 disc space.

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