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6. Spine MCQs

Practice Set 287 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 5721

Topic: 6. Spine

Why are L5-S1 disc herniations often considered more challenging or associated with a slightly higher risk of nerve root injury during discectomy compared to L4-L5 herniations?

. The S1 nerve root is larger and more fragile.
. The L5-S1 interspace is typically narrower and more acutely angled.
. There is a greater quantity of disc material at L5-S1.
. The posterior longitudinal ligament is stronger at L5-S1.
. L5-S1 herniations are more frequently associated with Cauda Equina Syndrome.

Correct Answer & Explanation

. The L5-S1 interspace is typically narrower and more acutely angled.

Explanation

The L5-S1 interspace is often narrower and more acutely angled (lumbosacral angle), which can make surgical access more challenging and increase the risk of nerve root manipulation or injury. The S1 nerve root is also more vulnerable to injury due to its anatomical course. While other factors contribute, the anatomical constraints are a key reason.

Question 5722

Topic: 6. Spine

A large central disc herniation at L4-L5 is MOST likely to cause which of the following symptom patterns?

. Unilateral L5 radiculopathy
. Isolated L4 motor weakness
. Saddle anesthesia and bladder dysfunction
. Unilateral S1 radiculopathy
. Exclusive axial low back pain

Correct Answer & Explanation

. Saddle anesthesia and bladder dysfunction

Explanation

A large central disc herniation, particularly if it compresses multiple nerve roots in the central canal, can cause symptoms of Cauda Equina Syndrome, including saddle anesthesia and bladder dysfunction. While it can cause bilateral radiculopathy, saddle anesthesia and bladder dysfunction are more specific to significant central compression of the cauda equina. Unilateral radiculopathies are more typical of posterolateral herniations. Isolated axial back pain suggests discogenic pain without radicular involvement.

Question 5723

Topic: 6. Spine

A rare true central disc herniation at L5-S1, if symptomatic, would primarily impact which nerve roots?

. L5 traversing nerve roots bilaterally
. S1 traversing nerve roots bilaterally
. L4 traversing nerve roots bilaterally
. L5 exiting nerve roots unilaterally
. S2 traversing nerve roots unilaterally

Correct Answer & Explanation

. S1 traversing nerve roots bilaterally

Explanation

A true central disc herniation at L5-S1 would compress the traversing S1 nerve roots bilaterally, as they are located centrally within the canal at that level before exiting. The L5 nerve roots would have already exited at the L5-S1 foramen.

Question 5724

Topic: 6. Spine

When evaluating a child or adolescent with suspected lumbar disc herniation, what unique consideration is often found compared to adults?

. Higher incidence of disc sequestration
. More common presentation with Cauda Equina Syndrome
. Greater likelihood of associated spinal deformity (e.g., scoliosis)
. Less pain but more neurological deficit
. Increased incidence of bilateral radiculopathy

Correct Answer & Explanation

. More common presentation with Cauda Equina Syndrome

Explanation

Pediatric lumbar disc herniations are relatively rare. When they occur, they are more often associated with factors like trauma, vigorous sports, or underlying developmental conditions. They are also notably associated with a higher incidence of Cauda Equina Syndrome compared to adults, warranting particular vigilance.

Question 5725

Topic: 6. Spine

Under what specific circumstance might a lumbar fusion be considered concurrently with a discectomy for a primary disc herniation?

. All large disc extrusions
. Failure of conservative treatment
. Presence of significant preoperative segmental instability
. Patient request for long-term pain relief
. Recurrent disc herniation within 6 months of primary surgery

Correct Answer & Explanation

. Presence of significant preoperative segmental instability

Explanation

Lumbar fusion is typically not indicated for a primary disc herniation unless there is clear evidence of concomitant spinal instability (e.g., spondylolisthesis, significant degenerative changes leading to instability on dynamic imaging) or in cases of severe recurrent herniation where prior discectomy has failed to stabilize the segment. It is not indicated for all large extrusions, for general failure of conservative treatment without instability, or merely due to patient request.

Question 5726

Topic: 6. Spine

The posterolateral aspect of the annulus fibrosus is particularly vulnerable to herniation due to what anatomical feature?

. It is the thickest part of the annulus.
. It is reinforced by the anterior longitudinal ligament.
. The posterior longitudinal ligament is narrower and thinner centrally and posterolaterally.
. It is avascular, leading to poor healing.
. It contains more proteoglycans than other regions.

Correct Answer & Explanation

. The posterior longitudinal ligament is narrower and thinner centrally and posterolaterally.

Explanation

The posterior longitudinal ligament (PLL) is broadest cranially and narrows significantly as it descends into the lumbar spine, especially at the L4-L5 and L5-S1 levels, leaving the posterolateral annulus fibrosus less reinforced and more susceptible to herniation.

Question 5727

Topic: 6. Spine

A 55-year-old patient presents with chronic L5 radiculopathy for over 6 months. An MRI shows a disc herniation. On EMG, fibrillation potentials and positive sharp waves are detected in the tibialis anterior muscle. What do these findings signify?

. Acute nerve root compression
. Complete nerve transaction
. Active denervation and ongoing nerve damage
. Nerve root recovery
. Psychogenic pain

Correct Answer & Explanation

. Active denervation and ongoing nerve damage

Explanation

Fibrillation potentials and positive sharp waves on EMG indicate active denervation, meaning there is ongoing nerve damage and muscle fiber irritation due to the nerve lesion. These findings typically appear 2-3 weeks after acute injury. They suggest a chronic or ongoing compressive radiculopathy. Acute compression without denervation usually presents with slowed conduction, and recovery would show reinnervation potentials.

Question 5728

Topic: 6. Spine

Which of the following is an absolute contraindication to an epidural steroid injection for lumbar radiculopathy?

. Diabetes mellitus
. Anticoagulant therapy
. Systemic hypertension
. Active infection at the injection site or systemic infection
. History of gastrointestinal bleed

Correct Answer & Explanation

. Active infection at the injection site or systemic infection

Explanation

An active infection at the injection site (e.g., cellulitis, abscess) or a systemic infection (e.g., sepsis, osteomyelitis) is an absolute contraindication to epidural steroid injection due to the risk of spreading the infection into the spinal canal (epidural abscess, meningitis). While anticoagulant therapy is a relative contraindication due to bleeding risk, and diabetes/hypertension require careful monitoring, active infection is an absolute contraindication.

Question 5729

Topic: 6. Spine

To minimize the risk of lumbar disc herniation during lifting, which of the following techniques is MOST important?

. Lifting heavy objects quickly
. Twisting the torso while lifting
. Keeping the object away from the body
. Bending at the knees and hips, keeping the back straight
. Exhaling forcefully during the lift

Correct Answer & Explanation

. Bending at the knees and hips, keeping the back straight

Explanation

The most important lifting technique to protect the lumbar spine is to bend at the knees and hips, keeping the back straight and the object close to the body. This minimizes the lever arm and distributes the load to the stronger leg muscles rather than the spinal discs and ligaments. Twisting and lifting quickly increase risk.

Question 5730

Topic: 6. Spine

On an MRI, a "high intensity zone" (HIZ) within the posterior annulus fibrosus is sometimes observed. What is the clinical significance of a HIZ in patients with discogenic low back pain?

. It confirms disc herniation
. It is a reliable indicator of nerve root compression
. It is often associated with symptomatic annular tears and discogenic pain
. It indicates early disc regeneration
. It is an incidental finding with no clinical significance

Correct Answer & Explanation

. It is often associated with symptomatic annular tears and discogenic pain

Explanation

A high intensity zone (HIZ) on T2-weighted MRI, typically seen in the posterior annulus, is believed to represent an area of annular tear with granulation tissue and inflammatory changes. While its clinical significance is debated, it is often associated with symptomatic internal disc disruption and discogenic low back pain, though it doesn't confirm herniation or nerve root compression and can be an incidental finding in asymptomatic individuals too.

Question 5731

Topic: 6. Spine

A patient has chronic debilitating sciatic pain for over 6 months. MRI shows only mild degenerative disc disease with no clear herniation or stenosis. EMG is normal. Physical exam reveals tenderness in the gluteal region and reproduction of sciatic pain with palpation over the piriformis muscle. What is the MOST appropriate next step in management?

. Repeat lumbar MRI with contrast
. Exploratory lumbar microdiscectomy
. Piriformis muscle injection with local anesthetic and corticosteroid
. Referral for spinal fusion
. Prescription of high-dose oral corticosteroids

Correct Answer & Explanation

. Piriformis muscle injection with local anesthetic and corticosteroid

Explanation

Given the chronic sciatic pain, normal lumbar MRI for herniation/stenosis, normal EMG, and physical findings consistent with piriformis syndrome, a diagnostic and therapeutic piriformis muscle injection with local anesthetic and corticosteroid is the most appropriate next step. This helps confirm the diagnosis and can provide symptomatic relief. Repeat MRI is unlikely to yield new information. Surgery is not indicated without a clear structural lesion.

Question 5732

Topic: 6. Spine

What is the primary role of plain lumbar radiographs in the initial evaluation of a patient with suspected lumbar disc herniation?

. To definitively diagnose disc herniation
. To assess for nerve root compression
. To rule out other pathologies like fracture, tumor, or significant instability
. To quantify disc hydration
. To measure intradiscal pressure

Correct Answer & Explanation

. To rule out other pathologies like fracture, tumor, or significant instability

Explanation

Plain radiographs do not directly visualize disc herniations or nerve root compression. Their primary role in the context of suspected disc herniation is to rule out other significant osseous pathologies such as fractures, tumors, infections, or severe spondylolisthesis/instability that might present with similar symptoms. They can show degenerative changes but are not diagnostic for herniation itself.

Question 5733

Topic: 6. Spine

A patient presents with severe low back pain and fever several weeks after a lumbar microdiscectomy. Laboratory tests show elevated ESR and CRP. MRI reveals T2 hyperintensity in the disc space with endplate signal changes. This presentation is most consistent with:

. Recurrent disc herniation
. Failed Back Surgery Syndrome
. Discitis
. Spinal stenosis
. Post-dural puncture headache

Correct Answer & Explanation

. Discitis

Explanation

The combination of severe low back pain, fever, elevated inflammatory markers (ESR, CRP) after spine surgery, and specific MRI findings (T2 hyperintensity in disc space, endplate changes) is highly suggestive of discitis (disc space infection). Recurrent herniation would not typically cause fever or elevated inflammatory markers to this extent.

Question 5734

Topic: 6. Spine

A patient with a degenerative spondylolisthesis at L4-L5 presents with acute L5 radiculopathy. On MRI, a disc herniation is also noted at the same level. Why might surgery for this patient be more complex or require a different approach than for an isolated disc herniation?

. Degenerative spondylolisthesis typically precludes microdiscectomy.
. The herniation is usually smaller in cases of spondylolisthesis.
. The instability associated with the spondylolisthesis may also need to be addressed.
. Spondylolisthesis causes increased dural tension.
. The nerve roots are rarely compressed in such cases.

Correct Answer & Explanation

. The instability associated with the spondylolisthesis may also need to be addressed.

Explanation

When a disc herniation occurs in the context of degenerative spondylolisthesis, the underlying instability caused by the slip may also contribute to the patient's symptoms or could be exacerbated by simple decompression. In such cases, a fusion procedure (e.g., PLIF, TLIF) along with decompression may be necessary to stabilize the segment and prevent further slip or recurrence of symptoms, rather than just a microdiscectomy.

Question 5735

Topic: 6. Spine

Which of the following patient characteristics is generally associated with the BEST surgical outcome following lumbar microdiscectomy for radiculopathy?

. Symptoms predominantly axial low back pain
. Symptoms > 1 year in duration
. Clear, unilateral radicular pain with concordant imaging findings
. Presence of significant psychological overlay
. Multiple previous lumbar spine surgeries

Correct Answer & Explanation

. Clear, unilateral radicular pain with concordant imaging findings

Explanation

Patients with clear, unilateral radicular pain that directly correlates with an identifiable disc herniation on imaging generally have the best surgical outcomes from microdiscectomy. Axial back pain is less reliably relieved by discectomy. Long duration of symptoms, psychological factors, and prior surgeries are all negative prognostic indicators.

Question 5736

Topic: 6. Spine

On a sagittal view of a lumbar MRI, which plane provides the MOST detailed visualization of the neural foramen and the exiting nerve roots?

. Mid-sagittal
. Parasagittal (through the pedicle)
. Parasagittal (through the lamina)
. Coronal
. Axial

Correct Answer & Explanation

. Parasagittal (through the pedicle)

Explanation

While axial views show the contents of the foramen, the parasagittal viewthrough the pedicleprovides the most detailed visualization of the neural foramen and the exiting nerve roots as they pass through it, allowing assessment of foraminal stenosis or far lateral disc herniations. Mid-sagittal views primarily show the central canal. Coronal and axial are different planes.

Question 5737

Topic: 6. Spine

A 70-year-old male presents with new onset L4 radiculopathy. His history includes severe peripheral vascular disease. Which of the following diagnostic procedures should be used with caution or avoided in this patient?

. Plain lumbar radiographs
. MRI of the lumbar spine
. CT myelogram
. Nerve conduction studies
. Physical examination

Correct Answer & Explanation

. CT myelogram

Explanation

A CT myelogram involves the intrathecal injection of iodinated contrast material. In patients with severe peripheral vascular disease or other conditions causing compromised kidney function, the use of iodinated contrast carries a risk of contrast-induced nephropathy. While MRI with gadolinium also has a risk of nephrogenic systemic fibrosis in severe renal impairment, a CT myelogram's contrast load is often higher and the procedure more invasive, warranting caution. Plain radiographs, MRI (non-contrast or with caution for contrast), NCS, and physical exam are generally safer.

Question 5738

Topic: 6. Spine

What is the primary reason that surgical discectomy for lumbar disc herniation typically provides more rapid relief of radicular pain compared to conservative management?

. Surgery induces a strong inflammatory response that resolves disc material quickly.
. It strengthens the surrounding spinal ligaments.
. It directly removes the mechanical compression on the nerve root.
. Surgery improves blood flow to the nerve root.
. It prevents future disc degeneration.

Correct Answer & Explanation

. It directly removes the mechanical compression on the nerve root.

Explanation

The primary advantage of surgical discectomy is the direct mechanical decompression of the nerve root by removing the herniated disc material. This immediate relief of compression often leads to more rapid resolution of radicular pain compared to the slower process of spontaneous resolution seen with conservative management. While inflammation and blood flow can play a role, direct mechanical relief is the key immediate effect. It does not strengthen ligaments or prevent future degeneration.

Question 5739

Topic: 6. Spine

Which of the following is considered a 'red flag' symptom in a patient presenting with acute low back pain and suspected lumbar disc herniation, necessitating immediate further investigation?

. Pain radiating below the knee
. Pain worse with coughing or sneezing
. Unilateral motor weakness (e.g., foot drop)
. Unexplained weight loss and night sweats
. History of previous lumbar disc herniation

Correct Answer & Explanation

. Unexplained weight loss and night sweats

Explanation

Unexplained weight loss and night sweats are 'red flag' symptoms suggestive of a serious underlying condition such as malignancy or infection, which require urgent investigation. While motor weakness is a significant finding that may expedite treatment, it is not as strong a red flag for life-threatening conditions as constitutional symptoms like unexplained weight loss and night sweats. Radiating pain and pain with Valsalva maneuvers are common symptoms of disc herniation.

Question 5740

Topic: 6. Spine

A 9-year-old girl with Neurofibromatosis type 1 is being evaluated for a spinal deformity. Which of the following radiographic features is most indicative of a 'dystrophic' curve, which carries a high risk of rapid progression?

. A long, sweeping C-shaped thoracolumbar curve.
. Congenital block vertebrae at the apex of the curve.
. A right thoracic curve with normal sagittal alignment.
. Spondylolysis at the L5-S1 junction.
. Vertebral body scalloping, severe apical rotation, and penciling of the ribs.

Correct Answer & Explanation

. Vertebral body scalloping, severe apical rotation, and penciling of the ribs.

Explanation

Correct Answer: Vertebral body scalloping, severe apical rotation, and penciling of the ribs.Spinal deformities in NF1 are classified as non-dystrophic (resembling idiopathic scoliosis) or dystrophic. Dystrophic curves are characterized by sharp, short-segment angular curves, severe apical rotation, vertebral body wedging, posterior vertebral scalloping, widened interpedicular distances, enlarged neural foramina, and 'penciling' or spindling of the transverse processes and ribs. These curves have a very high propensity for rapid progression and often require early, aggressive surgical stabilization (often combined anterior and posterior fusion) to prevent severe deformity and neurologic compromise.

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