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 5661
Topic: 6. Spine
A 25-year-old male with a history of long-standing systemic juvenile idiopathic arthritis (JIA) presents with worsening neck stiffness. Radiographs of the cervical spine are most likely to demonstrate which of the following classical findings?
Correct Answer & Explanation
. Ankylosis of the facet joints starting at the upper cervical spine
Explanation
Cervical spine involvement in JIA typically presents with apophyseal (facet) joint ankylosis. This classically begins in the upper cervical spine (C2-C3) and progresses caudally, which severely restricts motion.
Question 5662
Topic: 6. Spine
A 6-year-old child presents with a waddling gait, joint pain, and short stature. Radiographs demonstrate delayed ossification and irregular, fragmented epiphyses in multiple joints (hips, knees, ankles), but the spine appears radiographically normal. What is the most likely diagnosis?
Correct Answer & Explanation
. Multiple epiphyseal dysplasia
Explanation
Multiple epiphyseal dysplasia (MED) involves irregular, delayed ossification of the epiphyses leading to premature osteoarthritis, but classically spares the spine. This key feature distinguishes it from spondyloepiphyseal dysplasia (SED), which has prominent spinal involvement.
Question 5663
Topic: 6. Spine
A 3-month-old infant is diagnosed with achondroplasia. Which of the following spinal abnormalities is most critical to screen for during the first year of life to prevent sudden mortality?
Correct Answer & Explanation
. Foramen magnum stenosis
Explanation
Infants with achondroplasia are at high risk for foramen magnum stenosis due to abnormal endochondral ossification of the skull base. This can cause cervicomedullary compression, leading to central sleep apnea and sudden infant death.
Question 5664
Topic: 6. Spine
During the physical exam, a patient with a history of recurrent anterior dislocations expresses apprehension when you gently attempt to externally rotate their arm with the shoulder abducted to 90 degrees. What is the next logical step to confirm instability?
Correct Answer & Explanation
. Apply a posterior force to the humeral head while maintaining the position (Relocation Test)
Explanation
If the Apprehension Test is positive (patient feels apprehension), the next step is often to perform the Relocation Test (also known as the Fulcrum Test or Jobe Relocation Test). By applying a posterior force to the humeral head while maintaining the abducted and externally rotated position, if the apprehension or pain decreases, it confirms anterior instability. This sequence differentiates true instability from generalized shoulder pain. Reducing the shoulder is premature. Sulcus sign tests inferior instability. MRI is an imaging study, not an immediate physical exam confirmation. Cervical spine ROM is not directly related to shoulder instability confirmation.
Question 5665
Topic: Cervical Spine
In an anterior cervical discectomy and fusion (ACDF), what type of screws are typically used to fix the plate to the vertebral bodies?
Correct Answer & Explanation
. Self-tapping locking screws to create a fixed-angle construct.
Explanation
In ACDF, anterior cervical plates are typically secured with self-tapping locking screws. These screws thread into the plate, creating a fixed-angle construct that provides angular stability. This is crucial in the cervical spine to maintain reduction, prevent toggling, and provide a stable environment for fusion. While unicortical purchase is often sufficient due to the locking mechanism, some designs allow for bicortical fixation. The self-tapping feature facilitates insertion in the dense cortical bone of the vertebral bodies.
Question 5666
Topic: 6. Spine
A 65-year-old man presents with progressive clumsiness in his hands and broad-based gait. Examination reveals hyperreflexia and a positive Hoffman's sign. MRI shows cervical spondylotic myelopathy. Which of the following sagittal canal diameters is generally considered the absolute threshold for critical cervical stenosis?
Correct Answer & Explanation
. 10 mm
Explanation
A sagittal cervical canal diameter of less than 10 mm is highly correlated with critical cervical stenosis and myelopathy. The normal sagittal diameter is 17-18 mm. A diameter of less than 13 mm defines congenital cervical stenosis.
Question 5667
Topic: Thoracolumbar Spine & Deformity
According to the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following posterior ligamentous complex (PLC) statuses contributes the highest number of points to the total score?
Correct Answer & Explanation
. Disrupted
Explanation
In the TLICS scoring system, the Posterior Ligamentous Complex (PLC) status is scored as follows: Intact = 0 points, Suspected/Indeterminate = 2 points, Disrupted = 3 points. A total score of >4 generally indicates surgical management.
Question 5668
Topic: 6. Spine
A 40-year-old man falls from a height of 20 feet and sustains a burst fracture of T12. On examination in the trauma bay, he has flaccid paralysis of his lower extremities, absent lower extremity reflexes, and an absent bulbocavernosus reflex. His vital signs are stable (HR 85 bpm, BP 120/80 mmHg). The absence of the bulbocavernosus reflex in this setting most accurately signifies which of the following?
Correct Answer & Explanation
. Spinal shock
Explanation
The bulbocavernosus reflex is a polysynaptic reflex mediated by the S2-S4 segments of the spinal cord. Its absence in the acute phase of a severe spinal injury indicates a state of 'spinal shock'—a temporary physiologic disruption of spinal cord function and reflexes below the level of injury. A spinal cord injury cannot be officially classified as complete or incomplete until the patient emerges from spinal shock (indicated by the return of the bulbocavernosus reflex). Neurogenic shock refers to hemodynamic instability (bradycardia and hypotension) due to loss of sympathetic tone, which this patient does not have.
Question 5669
Topic: 6. Spine
What distinguishes a pedicle screw, commonly used in spinal fixation, from a standard cortical screw?
Correct Answer & Explanation
. Pedicle screws have a larger diameter and a dual-pitch thread designed to engage both cortical and cancellous bone.
Explanation
Pedicle screws are designed for the specific biomechanical demands of the spine. They typically have a larger diameter to fill the pedicle, and often feature a dual-pitch or cancellous-type thread pattern to gain purchase in both the dense cortical bone of the pedicle walls and the cancellous bone within the pedicle. This design provides robust fixation. While some are self-tapping (A), it's not universal. Dual-lead (B) refers to thread count, not a primary distinguishing feature of 'pedicle' vs 'cortical'. A narrower core diameter (D) would reduce screw strength. Bioabsorbable (E) are not typical for pedicle screws.
Question 5670
Topic: 6. Spine
When comparing stainless steel and titanium implants, titanium is generally preferred in which specific scenario?
Correct Answer & Explanation
. When MRI compatibility is a significant concern.
Explanation
Titanium (and its alloys) produces less ferromagnetic artifact on MRI scans compared to stainless steel. Therefore, when future MRI imaging of the implant site is a significant concern (e.g., spinal hardware or around joints where soft tissue visualization is crucial), titanium implants are generally preferred (C). Stainless steel is often less expensive (A). Stainless steel often has superior fatigue strength (B). Neither titanium nor stainless steel has strong bactericidal properties (D). Acute bone-implant interface strength (E) depends more on screw design and bone quality than the specific metal, though titanium is generally more osteoconductive in the long term.
Question 5671
Topic: 6. Spine
A 72-year-old female presents with severe low back pain radiating into her bilateral thighs, worse with standing and walking, significantly limiting her ambulation distance. She has a history of progressive worsening spinal deformity. Examination reveals a trunk shift to the left, mild right hip flexion contracture, and neurological deficits consistent with multilevel lumbar stenosis. Imaging shows a lumbar scoliotic curve with significant sagittal imbalance (C7 plumb line > 5 cm anterior to sacral promontory) and degenerative changes at multiple levels. Despite extensive conservative treatment, her pain remains debilitating (ODI score 65). Which surgical strategy is most likely to provide durable symptomatic relief and correction of deformity?
Correct Answer & Explanation
. Long-segment posterior spinal fusion extending from the thoracolumbar junction to the sacrum with pedicle screw instrumentation and interbody support.
Explanation
The patient presents with severe adult degenerative scoliosis with significant sagittal imbalance (C7 plumb line > 5 cm), neurological symptoms (lumbar stenosis), and functional limitation (high ODI score) despite conservative care. Decompression alone or limited fusion will likely lead to progression of deformity, junctional kyphosis, and persistent pain due to the uncorrected sagittal imbalance and continued instability. Minimally invasive short-segment fusions may not adequately address severe multilevel deformity and sagittal imbalance. A long-segment posterior spinal fusion from the thoracolumbar junction to the sacrum, combined with interbody support to restore lordosis and correct coronal deformity, is the most appropriate and durable solution for significant adult degenerative scoliosis with global imbalance.
Question 5672
Topic: 6. Spine
A 60-year-old female presents with chronic low back pain, bilateral lower extremity radicular pain, and neurogenic claudication. Imaging reveals a Grade II degenerative lumbar spondylolisthesis at L4-L5 with severe spinal stenosis and instability (dynamic flexion-extension radiographs show translation > 4 mm). She has failed 6 months of comprehensive non-operative treatment. What is the most appropriate surgical intervention?
Correct Answer & Explanation
. Instrumented posterior lumbar interbody fusion (PLIF) at L4-L5.
Explanation
This patient has symptomatic Grade II degenerative spondylolisthesis with spinal stenosis, instability, and failed conservative management. Decompression alone for degenerative spondylolisthesis is associated with a high rate of recurrent instability and worsening of the slip, often necessitating subsequent fusion. Microdiscectomy is for herniated discs, not primarily spondylolisthesis with stenosis and instability. ALIF alone provides anterior column support but typically requires posterior instrumentation for robust stability in spondylolisthesis, and doesn't directly decompress the posterior elements. Instrumented posterior lumbar interbody fusion (PLIF or TLIF) addresses all aspects: decompression of the neural elements posteriorly, restoration of disc height and alignment with interbody fusion, and rigid fixation with pedicle screws, which is the gold standard for symptomatic degenerative spondylolisthesis with instability. The question specifies L4-L5, so TLIF at L5-S1 is incorrect.
Question 5673
Topic: Thoracolumbar Spine & Deformity
A 65-year-old male presents with severe intractable low back pain and progressive stooped posture, limiting his ability to ambulate. Radiographs reveal a scoliotic curve of 45 degrees, sagittal vertical axis (SVA) of +10 cm, pelvic incidence (PI) of 60 degrees, and lumbar lordosis (LL) of 20 degrees. His pelvic tilt (PT) is 35 degrees. What is the primary surgical goal in correcting his sagittal imbalance?
Correct Answer & Explanation
. Match lumbar lordosis (LL) to pelvic incidence (PI) within 9 degrees.
Explanation
This patient presents with significant adult spinal deformity, particularly sagittal imbalance, characterized by a large positive sagittal vertical axis (SVA), reduced lumbar lordosis (LL 20°) relative to pelvic incidence (PI 60°), and a high pelvic tilt (PT 35°). For adult spinal deformity, particularly regarding sagittal balance, a key surgical goal is to restore the PI-LL mismatch to within a specific range (ideally PI ≈ LL, or PI-LL < 10 degrees). A PI-LL mismatch of 40 degrees (60-20) is severe and contributes significantly to his symptoms and imbalance. While reducing SVA to <5 cm and achieving PT <25 degrees are desired outcomes and indicators of successful sagittal correction, matching lumbar lordosis to pelvic incidence (PI-LL < 9 degrees) is the primary target for reconstructing the lumbar spine's lordosis to achieve a stable and balanced sagittal profile, which subsequently helps in normalizing SVA and PT. Coronal plane correction is important but often secondary to sagittal balance in symptomatic adults. Kyphoplasty addresses specific fractures, not global deformity.
Question 5674
Topic: 6. Spine
A 35-year-old male presents with a 6-month history of inflammatory low back pain, morning stiffness, and bilateral heel pain. He also reports recurrent episodes of painful red eye (uveitis). His rheumatoid factor and anti-CCP antibodies are negative. Radiographs of the sacroiliac joints show bilateral erosions and sclerosis. Which extra-articular manifestation is he most likely to develop in the future?
Correct Answer & Explanation
. Aortic insufficiency.
Explanation
This clinical picture (inflammatory back pain, morning stiffness, bilateral heel pain/enthesitis, recurrent uveitis, seronegativity for rheumatoid factor and anti-CCP, and radiographic evidence of sacroiliitis) is highly suggestive of Ankylosing Spondylitis (AS), a prototype of seronegative spondyloarthropathies. Among the listed options, aortic insufficiency (due to aortitis) is a well-recognized and specific cardiovascular extra-articular manifestation of AS, occurring in a significant minority of patients. Rheumatoid nodules (Option A) are characteristic of rheumatoid arthritis. Subcutaneous tophi (Option B) are associated with gout. Psoriatic plaques (Option D) are seen in psoriatic arthritis, another spondyloarthropathy, but the primary diagnosis here points to AS. While AS can cause upper lobe pulmonary fibrosis (Option E), aortic insufficiency is a distinct and specific cardiac complication that is commonly tested in relation to AS.
Question 5675
Topic: 6. Spine
A 65-year-old male presents with progressive back pain, claudication, and a sagittal vertical axis (SVA) of +12 cm. He has tried extensive non-operative management. Imaging shows severe degenerative scoliosis with a lumbar lordosis (LL) of 30 degrees and a pelvic incidence (PI) of 60 degrees. Which of the following is generally considered the most critical sagittal balance parameter to restore surgically for optimal patient-reported outcomes?
Correct Answer & Explanation
. Sagittal Vertical Axis (SVA) < 5 cm
Explanation
Restoring a Sagittal Vertical Axis (SVA) of less than 5 cm is a critical goal in adult spinal deformity surgery, as it has consistently shown the strongest correlation with improved patient-reported outcomes and reduced disability. While other parameters like PI-LL mismatch (<10 degrees, not 20), PT (<20-22 degrees, not 25), and LL are important, SVA is the most direct measure of global sagittal balance and often the primary target for symptomatic relief. TPA is a more recent and useful parameter but SVA remains a cornerstone.
Question 5676
Topic: 6. Spine
A 72-year-old female undergoes a long fusion from T10 to the pelvis for adult degenerative scoliosis with severe sagittal imbalance. Postoperatively, she develops new onset severe thigh pain and weakness, predominantly in the quadriceps. Her blood pressure has been well-controlled. What is the most likely cause of her symptoms?
Correct Answer & Explanation
. Femoral nerve neurapraxia due to malpositioning or retraction
Explanation
Femoral nerve neurapraxia or palsy is a recognized complication after long instrumented spinal fusions, particularly those extending to the pelvis. It can result from direct compression by surgical retractors (e.g., iliopsoas retraction), patient positioning (excessive hip flexion causing stretch), or local hematoma. Symptoms typically include quadriceps weakness, anterior thigh numbness, and pain. Spinal cord ischemia presents with broader neurological deficits (motor and sensory) below the level of ischemia, often including sphincter dysfunction. Iliac artery thrombosis would present with more acute and severe limb ischemia symptoms. Proximal junctional kyphosis is a structural failure, not an acute nerve injury. Retrograde ejaculation is a complication of sympathetic nerve injury in anterior lumbar approaches, not typically related to posterior long fusions and quadriceps weakness.
Question 5677
Topic: 6. Spine
A 68-year-old female presents with severe low back pain, radiculopathy, and progressive stooping posture due to adult degenerative scoliosis. Radiographs show a lumbar curve of 40 degrees, severe facet arthrosis, and significant sagittal malalignment. Which of the following radiographic parameters is most strongly correlated with health-related quality of life outcomes in adult spinal deformity and guides surgical correction strategy?
The pelvic incidence - lumbar lordosis (PI-LL) mismatch is a critical radiographic parameter for assessing sagittal balance in adult spinal deformity. A mismatch of >10-15 degrees is strongly correlated with increased pain, disability, and reduced health-related quality of life, making its correction a primary goal in surgical planning for improved outcomes. While Cobb angle assesses coronal deformity and TPA provides a global assessment, PI-LL mismatch specifically addresses the crucial relationship between pelvic parameters and lumbar lordosis for sagittal alignment and functional outcomes.
Question 5678
Topic: 6. Spine
A 25-year-old presents with a flail arm following a high-energy motorcycle accident 4 months ago, consistent with a complete C5-T1 brachial plexus avulsion. Intraoperative exploration and imaging confirm avulsion of nerve roots from the spinal cord, making direct nerve repair or grafting from proximal stumps impossible. What is the most appropriate next step in surgical management for optimal functional recovery?
Correct Answer & Explanation
. Nerve transfers (e.g., intercostal to musculocutaneous, accessory to suprascapular).
Explanation
In complete brachial plexus avulsion injuries, where nerve roots are torn directly from the spinal cord, there are no viable proximal stumps for direct nerve repair or grafting. In such cases, nerve transfers are the only viable surgical option to restore some functional movement. This involves utilizing expendable motor nerves (donor nerves, such as intercostal nerves or the accessory nerve) from adjacent areas to reinnervate critical target muscles (recipient nerves, like the musculocutaneous or suprascapular nerve). This must be performed within a critical time window (typically up to 6-9 months post-injury) for optimal motor reinnervation.
Question 5679
Topic: Thoracolumbar Spine & Deformity
A 35-year-old presents with a T12 burst fracture with 60% canal compromise and an incomplete neurological deficit (ASIA D). The patient also has significant kyphotic deformity (30 degrees) at the fracture site. What is the most appropriate surgical approach to address both the neurological deficit and the spinal stability and deformity?
Correct Answer & Explanation
. Combined anterior-posterior approach.
Explanation
For a T12 burst fracture with significant canal compromise (60%), an incomplete neurological deficit (ASIA D), and substantial kyphotic deformity (30 degrees), a combined anterior-posterior approach is often considered the most appropriate. The anterior approach allows for direct decompression of the neural elements by removing retropulsed bone fragments and reconstruction of the anterior column, which is crucial for restoring sagittal balance and stability. The posterior approach provides rigid segmental fixation and allows for better kyphosis correction through pedicle screw instrumentation, offering a comprehensive treatment of stability, deformity, and neurological compromise. While posterior-only approaches can be used, they often struggle with direct anterior decompression and severe kyphosis correction.
Question 5680
Topic: 6. Spine
A 55-year-old male presents with chronic low back pain radiating into his left buttock and posterior thigh, worsened by standing and walking, and relieved by sitting and leaning forward. He underwent a lumbar microdiscectomy 3 years ago at L4-L5, which provided temporary relief. Physical exam reveals mild left L5 dermatomal paresthesias and a positive 'shopping cart sign'. MRI shows moderate central canal stenosis at L4-L5 and L5-S1 due to facet hypertrophy and ligamentum flavum thickening, with no significant disc herniation. The most appropriate surgical intervention in this case, considering his prior surgery and current symptoms, would likely involve:
Correct Answer & Explanation
. Laminectomy and decompression at L4-L5 and L5-S1 without fusion.
Explanation
The patient's symptoms are classic for lumbar spinal stenosis (neurogenic claudication), worsened by extension and relieved by flexion ('shopping cart sign'). Given his prior microdiscectomy and current multilevel stenosis from facet hypertrophy and ligamentum flavum thickening, a repeat microdiscectomy is unlikely to address the primary issue. Laminectomy and decompression at L4-L5 and L5-S1 without fusion is often the treatment of choice for multilevel lumbar stenosis without significant instability or deformity, especially when symptoms are severe and conservative measures have failed. Fusion (Option B) would be considered if there was significant instability, spondylolisthesis, or a need for extensive facetectomy leading to iatrogenic instability. Interspinous process decompression (Option C) might be considered for isolated, milder stenosis but is less effective for multilevel severe stenosis. Epidural injections (Option E) are conservative and have likely been attempted or are unlikely to provide long-term relief given the chronic, severe nature of symptoms and prior surgery.
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