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6. Spine MCQs

Practice Set 163 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 3241

Topic: 6. Spine

A 45-year-old male is involved in a diving accident resulting in a cervical spine injury.

He presents awake, alert, and cooperative, but examination reveals a complete C5 ASIA A spinal cord injury. What is the most appropriate initial management for this bilateral facet dislocation?

. Immediate MRI to rule out disc herniation prior to any reduction attempts
. Urgent closed awake cervical traction and reduction
. Emergent open posterior reduction and fusion
. Emergent open anterior reduction and fusion
. High-dose intravenous methylprednisolone administration over 24 hours

Correct Answer & Explanation

. Urgent closed awake cervical traction and reduction

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation and a neurologic deficit, urgent closed reduction via skeletal traction is the standard of care. An MRI is not mandatory before attempting closed reduction in an examinable patient, as rapid decompression of the spinal cord is paramount.

Question 3242

Topic: 6. Spine

A 65-year-old male undergoes an L4-L5 decompression and pedicle screw fixation. During pedicle preparation, an instrument breaches the inferior cortical wall of the L4 pedicle. Which neural structure is most directly at risk for iatrogenic injury?

. L3 exiting nerve root
. L4 exiting nerve root
. L5 traversing nerve root
. S1 traversing nerve root
. Thecal sac

Correct Answer & Explanation

. L4 exiting nerve root

Explanation

In the lumbar spine, the exiting nerve root travels inferior to the pedicle of its corresponding numbered vertebra (e.g., the L4 nerve root exits through the L4-L5 foramen, traveling immediately inferior to the L4 pedicle). An inferior breach of the L4 pedicle puts the L4 exiting nerve root directly at risk. A medial breach puts the dural sac and traversing L5 root at risk.

Question 3243

Topic: 6. Spine
A 40-year-old man presents after a diving accident. He is awake, alert, and cooperative, but demonstrates bilateral upper and lower extremity weakness (incomplete tetraplegia). The lateral cervical radiograph shows a bilateral facet dislocation. What is the most appropriate next step in acute management to decompress the spinal cord?
. Stat MRI of the cervical spine
. Awake closed traction reduction with Gardner-Wells tongs
. Immediate anterior cervical discectomy and fusion
. Immediate posterior cervical laminectomy and fusion
. Administration of the NASCIS-III high-dose methylprednisolone protocol

Correct Answer & Explanation

. Awake closed traction reduction with Gardner-Wells tongs

Explanation

In an awake, alert, and examinable patient with a cervical facet dislocation and a neurologic deficit, urgent awake closed reduction via cranial traction is the standard of care to rapidly decompress the spinal cord. An MRI is required prior to closed reduction ONLY if the patient is unexaminable (e.g., obtunded, intubated) or fails closed reduction, to rule out a large anterior disc herniation that could be dragged into the canal during reduction.

Question 3244

Topic: Thoracolumbar Spine & Deformity

In the radiographic evaluation of adult spinal deformity, pelvic parameters are critical for restoring sagittal balance. Which of the following equations accurately defines the geometric relationship between pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS)?

. PI = PT + SS
. PI = PT - SS
. PT = PI + SS
. SS = PI x PT
. PI = (PT + SS) / 2

Correct Answer & Explanation

. PI = PT + SS

Explanation

Pelvic incidence (PI) is a fixed anatomical morphological parameter unique to each individual after skeletal maturity. It dictates the orientation of the pelvis and is geometrically equal to the sum of the pelvic tilt (PT) and the sacral slope (SS): PI = PT + SS. A patient's required lumbar lordosis is typically matched to their PI (LL = PI ± 9 degrees).

Question 3245

Topic: 6. Spine

A 65-year-old male presents with worsening hand clumsiness and gait instability. Physical examination reveals a positive Hoffmann sign bilaterally and hyperreflexia in the lower extremities. Which of the following is the most sensitive imaging modality to evaluate the exact extent of the likely underlying pathology?

. Upright dynamic radiographs of the cervical spine
. Non-contrast computed tomography (CT) of the cervical spine
. Magnetic resonance imaging (MRI) of the cervical spine
. Electromyography (EMG) and nerve conduction studies (NCS)
. Somatosensory evoked potentials (SSEP)

Correct Answer & Explanation

. Magnetic resonance imaging (MRI) of the cervical spine

Explanation

The patient's symptoms (hand clumsiness, gait instability) and signs (Hoffmann sign, hyperreflexia) are classic for cervical spondylotic myelopathy (CSM), an upper motor neuron lesion caused by spinal cord compression. MRI of the cervical spine is the gold standard and most sensitive imaging modality to evaluate soft tissue structures, the intervertebral discs, and the degree of spinal cord compression or intrinsic cord signal changes (myelomalacia).

Question 3246

Topic: Thoracolumbar Spine & Deformity

A 40-year-old construction worker falls from a scaffolding, sustaining an L1 burst fracture. He is neurologically intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following findings would unequivocally push his score to 5 or higher, thereby strongly favoring operative intervention?

. 20% loss of anterior vertebral body height
. 30% canal compromise by retropulsed bone fragments
. Disruption of the posterior ligamentous complex (PLC)
. Interpedicular widening on the AP radiograph
. Concomitant transverse process fractures

Correct Answer & Explanation

. Disruption of the posterior ligamentous complex (PLC)

Explanation

The TLICS scoring system aids in deciding whether a thoracolumbar fracture requires surgery. It is based on three categories: injury morphology, neurological status, and integrity of the posterior ligamentous complex (PLC). A burst fracture (morphology) gives 2 points. Intact neuro status gives 0 points. A confirmed disruption of the PLC adds 3 points. Thus, 2 + 0 + 3 = 5 points. A score of 4 can be treated conservatively or operatively (surgeon's choice), while a score greater than 4 strongly dictates operative intervention. Neither loss of height alone nor the degree of canal compromise automatically mandates surgery without neuro deficits or PLC injury.

Question 3247

Topic: Thoracolumbar Spine & Deformity

In the evaluation of a traumatic spine injury using the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following mechanisms of injury is assigned the highest number of points?

. Compression
. Burst
. Translation/Rotation
. Distraction
. Lateral compression

Correct Answer & Explanation

. Distraction

Explanation

The TLICS score assigns points based on morphology/mechanism: Compression (1 point), Burst (2 points), Translation/Rotation (3 points), and Distraction (4 points). Therefore, a distraction mechanism yields the highest point value in this category, reflecting the severe instability typical of these injuries (e.g., flexion-distraction/Chance fractures).

Question 3248

Topic: 6. Spine
A 40-year-old male is involved in a motor vehicle accident and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). Radiographs show significant translation of C2 on C3 with severe angulation, classified as a Levine-Edwards Type II fracture. What is the characteristic mechanism of injury for this specific fracture pattern?
. Pure axial loading resulting in burst morphology
. Hyperextension and axial loading followed by severe flexion
. Pure distraction with associated spinal cord transection
. Rotational shear leading to unilateral facet dislocation
. Lateral bending causing a compression fracture

Correct Answer & Explanation

. Hyperextension and axial loading followed by severe flexion

Explanation

Levine-Edwards classification of Hangman's fractures: Type I is caused by hyperextension and axial load (minimal displacement). Type II is characterized by initial hyperextension/axial loading causing the fracture, followed by severe rebound flexion causing displacement and angulation (disruption of the C2-C3 disc). Type IIA is flexion-distraction. Type III involves facet dislocation.

Question 3249

Topic: 6. Spine
A 27-year-old man has neck pain after being involved in a motor vehicle accident. A lateral cervical radiograph is shown in Figure 21. What would be the most common neurologic finding?
. Cruciate paralysis
. Quadriplegia
. Normal function
. Absent bulbocavernosus reflex
. Greater occipital nerve dysesthesia

Correct Answer & Explanation

. Normal function

Explanation

The radiographic findings are consistent with a type II Hangman's fracture or traumatic spondylolisthesis of C2. This occurs with more than 3 mm of displacement according to the classification of Levine and Edwards. Even though the radiograph reveals significant displacement, the overall space available for the neural elements is increased, therefore minimizing the risk of neural compromise. Neurologic injury is most frequently encountered in type III injuries that are associated with bilateral facet dislocations of C2 on C3 but is infrequent in type I (less than 3 mm displacement) and type II traumatic spondylolisthesis. When neurologic deficits are associated with type II injuries, it is usually the result of an associated head injury.

Question 3250

Topic: 6. Spine

A 73-year-old woman reports a 4-month history of severe left-sided posterior buttock pain and left leg pain. The leg pain radiates into the left lateral thigh and posterior calf with cramping. Examination reveals mild difficulty with a single-leg toe raise on the left side and a diminished ankle reflex. There is also a significant straight leg raise test at 45 degrees which exacerbates symptoms. An MRI scan is shown in Figure 4. What is the most appropriate treatment at this time?

Orthopedic Surgery Board Review 2026 | High-Yield MCQs - Set 2 - Figure 1

. Lumbar laminectomy with synovial cyst excision
. Repeat epidural steroid injection
. Microdiskectomy at L4-5
. Nonsteroidal medication and outpatient physical therapy
. Left-sided facet blocks at L4-5 and L5-S1

Correct Answer & Explanation

. Lumbar laminectomy with synovial cyst excision

Explanation

Lumbar spinal stenosis with lumbar radiculopathy can be commonly caused by a synovial cyst arising from the facet joints. Lyons and associates reported on the surgical treatment of synovial cysts in 194 patients. Of the 147 with follow-up data, 91% reported good pain relief and 82% had improvement of their motor deficits. Epstein reported a 58% to 63% incidence of good/excellent results and a 38 to 42 point improvement on the SF-36 Physical Function Scale. It was also suggested that since the presence of a synovial cyst indicates facet pathology, possible fusion should be considered in these patients, especially those with underlying spondylolisthesis. Lyons MK, Atkinson JL, Wharen RE, et al: Surgical evaluation and management of lumbar synovial cysts: The Mayo Clinic Experience. J Neurosurg 2000;93:53-57. Khan AM, Synnot K, Cammisa FP, et al: Lumbar synovial cysts of the spine: An evaluation of surgical outcome. J Spinal Disord Tech 2005;18:127-131.

Question 3251

Topic: 6. Spine

A previously healthy 29-year-old man reports a 2-day history of severe atraumatic lower back pain. He denies any bowel or bladder difficulties and no constitutional signs. Examination is consistent with mechanical back pain. No focal neurologic deficits or pathologic reflexes are noted. What is the most appropriate management?

. Radiographs, including anterior, lateral, and oblique views
. MRI of the lumbar spine and follow-up at the clinic in 1 week
. Caudal epidural steroid injection
. Reassurance, limited analgesics, and early range of motion as tolerated
. Immediate MRI of the lumbar spine and possible urgent surgical decompression

Correct Answer & Explanation

. Reassurance, limited analgesics, and early range of motion as tolerated

Explanation

In general, a previously healthy patient with an acute onset of nontraumatic lower back pain does not need diagnostic imaging before proceeding with therapeutic treatment. In the absence of any "red flags" during the history and physical examination, such as trauma or constitutional symptoms (ie, fevers, chills, weight loss), the appropriate treatment for acute onset lower back pain is purely symptomatic treatment including limited analgesics and early range of motion. Diagnostic imaging is not necessary unless the initial treatment is unsuccessful and symptoms are prolonged. Miller and associates suggested that the use of radiographs can lead to better patient satisfaction but not necessarily better outcomes. Miller P, Kendrick D, Bentley E, et al: Cost effectiveness of lumbar spine radiographs in primary care patients with low back pain. Spine 2002;27:2291-2297.

Question 3252

Topic: 6. Spine

A 53-year-old man reports a 5-week history of worsening low back pain accompanied by bilateral knee and ankle pain and swelling. He also reports a lesser degree of neck and left elbow pain. He denies any history of trauma or provocative episodes. His medical history is significant for Reiter's syndrome more than 25 years ago, with no subsequent exacerbations. Furthermore, he has recently returned from a vacation in Costa Rica and noted the development of infectious gastroenteritis with diarrhea within 1 week of his return. This was treated with a 10-day course of oral antibiotics and has since resolved. He denies any significant bowel or urinary symptoms at this time. His neurologic examination is essentially within normal limits, but is somewhat limited by his low back and leg pain. What further investigation is most appropriate at this time?

. Radiographs of the lumbar spine and bilateral knees and ankles
. MRI of the lumbar spine with and without gadolinium contrast
. Synovial fluid analysis of the involved joints for crystals and bacteria
. Laboratory tests including a CBC count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)
. Laboratory tests including CBC count, rheumatoid factor (RF), antinuclear antibodies (ANA), and human leukocyte antigen-B27 (HLA-B27)

Correct Answer & Explanation

. Laboratory tests including a CBC count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)

Explanation

The patient has pain involving the cervical and lumbar spine as well as pain and swelling in both the knees and ankles. As such, this can be classified as polyarticular arthritis. The presence of multiple joint symptoms in the lower extremities, the absence of a history of trauma, and the multiple joints involved direct attention away from the spine as the etiology of this patient's pain. Radiographs of the involved joints are not likely to yield much useful information to assist with a diagnosis. Likewise, an MRI scan of the lumbar spine is not likely to provide much information regarding the etiology of the patient's condition. When a rheumatologic illness is suspected, the selective use of confirmatory laboratory testing can aid in arriving at a correct diagnosis. A presumed case of gout or chondrocalcinosis can be confirmed by the presence of the appropriate crystals in a joint-fluid aspiration. Because of the patient's recent trip to Costa Rica and the subsequent gastroenteritis, a CBC count, ESR, and CRP should be ordered to rule out infectious and inflammatory versus noninflammatory conditions. Rheumatoid factor (RF) in general should only be ordered for patients with polyarticular joint inflammation for more than 6 weeks. The presence of rheumatoid factor does not indicate rheumatoid arthritis. Antinuclear antibodies (ANA) should be ordered when a connective tissue disease such as systemic lupus erythematosus (SLE) is suspected on the basis of specific history and physical examination findings, such as inflammatory arthritis. Human leukocyte antigen-B27 (HLA-B27) should be ordered only when the patient's history is compatible with ankylosing spondylitis or Reiter's syndrome and this patient had a history of Reiter's syndrome. Gardner GC, Kadel NJ: Ordering and interpreting rheumatologic laboratory tests. J Am Acad Orthop Surg 2003;11:60-67.

Question 3253

Topic: 6. Spine

A 78-year-old woman undergoes her third lumbar decompression and fusion from L3 to L5 without complication. On the morning of postoperative day 3, examination reveals painless, flaccid weakness of both lower extremities. She also has an absent bulbocavernous reflex and a mild saddle paresthesia. MRI scans of the lumbar spine are shown in Figures 26a and 26b. What is the most appropriate management at this time?

. Continued serial neurologic examinations
. CT with a myelogram of the lumbar spine
. Immediate surgical exploration and hematoma drainage
. Electromyography of bilateral lower extremities
. IV antibiotics for 24 hours, followed by surgical exploration if symptoms persist

Correct Answer & Explanation

. Immediate surgical exploration and hematoma drainage

Explanation

The MRI scans reveal a large postoperative hematoma causing significant thecal compression. An epidural hematoma with neurologic deficit is a surgical emergency requiring immediate evacuation of the hematoma. Although the incidence of postoperative epidural hematomas is rare, the consequences of a missed diagnosis can be catastrophic. Early recognition and evacuation are essential in preserving or restoring neurologic function. Uribe and associates attributed delayed postoperative hematomas to previous multiple lumbar surgeries as a possible contributing factor. Yi S, Yoon do H, Kim KN, et al: Postoperative spinal epidural hematoma: Risk factor and clinical outcome. Yonsei Med J 2006;47:326-332.

Question 3254

Topic: 6. Spine

A 79-year-old woman reports a history of left leg pain with walking. Her pain is exacerbated with walking and stair climbing, and her symptoms are improved by standing after she stops walking. Lumbar flexion does not provide any significant improvement of the symptoms and sitting does not significantly change symptoms. Her leg pain is worse at night and she obtains relief by hanging her leg over the side of the bed. The neurologic examination is essentially normal. Examination of the lower extremities demonstrates mild early trophic changes, and her pulses distally are palpable but are diminished bilaterally. Radiographs are shown in Figures 15a and 15b. What is the next most appropriate step in management?

. Decompression and posterior fusion at L4-L5
. Epidural steroid injection at L4-5
. Nonsteroidal medications and physical therapy for 6 weeks
. Measurement of the ankle-brachial index
. CT myelogram

Correct Answer & Explanation

. Measurement of the ankle-brachial index

Explanation

The patient has symptoms that are more consistent with vascular claudication than with the pseudoclaudication anticipated from lumbar spinal stenosis. Therefore, the patient is a candidate for further vascular work-up. The radiographs reveal early spinal stenosis and spondylolisthesis at L4-5 but also show significant calcification of the iliac arteries, suggestive of peripheral vascular disease. Vascular claudication is a manifestation of peripheral vascular disease and presents with crampy leg pain that is exacerbated by physical exertion. The pain is easily relieved by standing still or sitting. Unlike pseudoclaudication, a forward-flexed posture and/or sitting does not improve the symptoms. Night pain is common in vascular claudication due to the elevation of the extremities and patients often report pain improvement by hanging their extremities in a dependent position. In evaluation of a patient with suspected vascular claudication, the five "P's" of vascular insufficiency should be monitored, including pulselessness, paralysis, paresthesia, pallor, and pain. While pain and paresthesias can be common in both vascular claudication and pseudoclaudication, the presence of any of the remaining symptoms is suggestive of vascular disease. Aufderheide TP: Peripheral arteriovascular disease, in Rosen P, Barkin R (eds): Emergency Medicine: Concepts and Clinical Practice, ed 4. St Louis, MO, Mosby, 1998, pp 1826-1844.

Question 3255

Topic: 6. Spine

An elderly patient falls and sustains an extension injury to the neck that results in upper extremity weakness, spared perianal sensation, and lower extremity spasticity. These findings best describe what syndrome?

. Brown-Sequard
. Cauda equina
. Anterior cord
. Posterior cord
. Central cord

Correct Answer & Explanation

. Central cord

Explanation

These finding indicate central cord syndrome, and injury that is more common in the older population who have some degree of spondylosis. The physiologic insult can be a central spinal hematoma with resultant hematomyelia. Bowel and bladder functional return has a good prognosis, unlike the upper extremity motor loss. Cauda equina syndrome generally involves injury at the lumbar levels, with some degree of lower extremity motor loss. Posterior cord syndrome is characterized by preservation of motor function below the level of injury and position/vibratory sensory loss. Brown-Sequard syndrome, which is often produced by a penetrating injury, results in contralateral hypalgesia and ipsilateral weakness. Anterior cord syndrome has a poor prognosis for functional return; lower extremity findings include loss of light touch, sharp/dull, and temperature sensations below the level of injury, as well as motor function. Apple DF Jr: Spinal cord injury rehabilitation, in Rothman RH, Simeone FA (eds): The Spine, ed 3. Philadelphia, PA, WB Saunders, 1992, Chapter 31.

Question 3256

Topic: 6. Spine

A 7-year-old girl with spinal muscular atrophy (SMA) type II has popping of the left hip. Examination reveals painless subluxation of the joint in adduction with palpable reduction in abduction. Radiographs show coxa valga, subluxation of the left hip, and pelvic obliquity with elevation of the left hemipelvis. Treatment should consist of

General Orthopedics 2026 Practice Questions: Set 17 (Solved) - Figure 66

. observation.
. bilateral adductor and iliopsoas releases, with nighttime abduction bracing.
. proximal femoral varus osteotomy with internal fixation.
. proximal femoral varus osteotomy with volume-reducing periacetabular osteotomy.
. proximal femoral varus osteotomy with shelf acetabular augmentation.

Correct Answer & Explanation

. observation.

Explanation

Observation is the treatment of choice. Hip subluxation and dislocation are not uncommon in patients with SMA type II who are unlikely to be ambulatory. Scoliosis occurs in these patients 100% of the time and frequently creates pelvic obliquity. However, in long-term follow-up, patients with SMA type II and hip dislocations had little associated pain or functional limitations because of hip instability. In addition, recurrent hip subluxation after surgical treatment has been documented. Given the rarity of symptoms from hip instability in long-term follow-up, and the possibility of recurrent dislocation, surgical intervention for hip instability may expose SMA type II patients to undue surgical risk for minimal if any functional gain. Sporer SM, Smith BG: Hip dislocation in patients with spinal muscular atrophy. J Pediatr Orthop 2003;23:10-14.

Question 3257

Topic: 6. Spine

A 14-year-old female presents with progressive thoracolumbar scoliosis. Imaging reveals a Cobb angle of 65 degrees from T9-L3, with significant sagittal decompensation (T1 pelvic angle of 35 degrees, pelvic incidence 55 degrees, lumbar lordosis -30 degrees). She experiences worsening back pain and trunk shift. Prior bracing failed to halt progression.

Which of the following surgical strategies is most appropriate to address her deformity and sagittal balance?

. Posterior spinal fusion with instrumentation from T9-L3 without osteotomies.
. Anterior release and fusion followed by posterior spinal fusion T9-L3.
. Posterior spinal fusion with instrumentation from T9-L5 with pedicle subtraction osteotomy (PSO) at L2.
. Posterior spinal fusion with instrumentation from T9-S1, including iliac fixation, with multiple Smith-Petersen osteotomies (SPOs).
. Halo-gravity traction followed by staged posterior spinal fusion T9-L3.

Correct Answer & Explanation

. Posterior spinal fusion with instrumentation from T9-S1, including iliac fixation, with multiple Smith-Petersen osteotomies (SPOs).

Explanation

The patient presents with severe thoracolumbar scoliosis and significant sagittal decompensation (T1 pelvic angle of 35 degrees, target is < 20 degrees; Lumbar lordosis -30 degrees, target is closer to PI-10 +/- 9 degrees, so -45 to -55 degrees). A Cobb angle of 65 degrees is a significant coronal deformity. The primary goal is to correct both the coronal and sagittal planes. A large T1PA indicates a need for significant sagittal correction. Simple posterior spinal fusion without osteotomies (Option A) would not adequately correct the severe sagittal imbalance. Anterior release and fusion (Option B) is primarily for stiff curves or to maximize correction, but in this case, the sagittal imbalance is severe, and a PSO (pedicle subtraction osteotomy) or multiple SPOs (Smith-Petersen osteotomies) would be more effective for sagittal plane correction. PSO offers the most significant sagittal correction, typically 30-40 degrees per level. Multiple SPOs also offer significant sagittal correction. Given the severe sagittal imbalance and the need for global balance, extending the fusion to S1 with iliac fixation is crucial to prevent junctional kyphosis and ensure durable sagittal alignment, especially when performing osteotomies. A PSO at L2 (Option C) would give significant correction but fusing only to L5 might risk distal junctional problems if the L5-S1 segment remains uncorrected or overloaded. Halo-gravity traction (Option E) is typically used for very rigid, severe curves, often in younger patients or those with neuromuscular scoliosis, but less indicated as a primary method for this specific presentation with sagittal malalignment needing significant bony resection. Therefore, posterior spinal fusion with instrumentation to S1 including iliac fixation with multiple SPOs or a PSO is the most comprehensive strategy to restore coronal alignment, achieve appropriate lumbar lordosis, and restore overall sagittal balance.

Question 3258

Topic: 6. Spine

A 68-year-old female presents with severe axial back pain and difficulty standing upright, progressively worsening over several years. Standing lateral radiographs show a C7 plumb line falling 8 cm anterior to the sacral promontory, a pelvic incidence of 60 degrees, and a lumbar lordosis of -20 degrees. Pelvic tilt is 35 degrees. She has significant compensatory knee flexion and hip extension.

According to current spinal deformity principles, which surgical maneuver is most likely to restore her sagittal balance and improve her functional outcome?

. Posterior spinal fusion with instrumentation from T10-L5 with in-situ contouring.
. Lumbosacral fusion from L2-S1 with an L4-S1 anterior lumbar interbody fusion (ALIF).
. Posterior spinal fusion with instrumentation from T10-S1 with iliac fixation and a L4 pedicle subtraction osteotomy (PSO).
. Multiple Smith-Petersen osteotomies (SPOs) from T10-L5.
. Decompression and isolated fusion at L4-L5.

Correct Answer & Explanation

. Posterior spinal fusion with instrumentation from T10-S1 with iliac fixation and a L4 pedicle subtraction osteotomy (PSO).

Explanation

This patient presents with severe sagittal imbalance (C7 plumb line 8 cm anterior to sacral promontory, normal < 2 cm, ideally 0-2 cm posterior) and inadequate lumbar lordosis (LL -20 degrees) relative to her pelvic incidence (PI 60 degrees). The target lumbar lordosis should approximate PI ± 9 degrees, meaning she needs significantly more lordosis (ideally around -50 to -60 degrees). Her high pelvic tilt (35 degrees, normal < 20-25 degrees) and compensatory knee flexion and hip extension further confirm significant sagittal decompensation. She requires a substantial increase in lumbar lordosis to restore sagittal balance.Option A (Posterior spinal fusion T10-L5 with in-situ contouring) is unlikely to provide enough correction for such severe sagittal imbalance, particularly with a C7PL of 8cm anterior.Option B (Lumbosacral fusion L2-S1 with L4-S1 ALIF) can provide some lordosis, but an ALIF alone may not be sufficient for severe fixed sagittal plane deformities requiring more significant correction. Furthermore, extending only to L2 may not address the entire thoracolumbar kyphosis contributing to the imbalance.Option C (Posterior spinal fusion with instrumentation from T10-S1 with iliac fixation and an L4 pedicle subtraction osteotomy (PSO)) is the most appropriate choice. A PSO is a powerful osteotomy that allows for significant lordosis correction (typically 30-40 degrees at a single level). An L4 PSO is often chosen for its effectiveness in correcting lumbar kyphosis. Fusing from T10 to S1 with iliac fixation ensures that the entire affected segment is addressed, and distal fixation is robust enough to support the long construct and powerful correction. This comprehensive approach is necessary to achieve global sagittal balance and prevent distal junctional kyphosis.Option D (Multiple Smith-Petersen osteotomies (SPOs) from T10-L5) provide less correction per level (5-10 degrees) than a PSO and typically require several levels to achieve substantial lordosis. While possible, a PSO at one level often provides a more reliable and larger correction for severe fixed deformities. Fusing only to L5 also risks distal junctional problems given the severity.Option E (Decompression and isolated fusion at L4-L5) would not address the global sagittal imbalance.

Question 3259

Topic: Thoracolumbar Spine & Deformity

A 65-year-old female presents with progressive back pain and increasing truncal imbalance. Her sagittal balance parameters show a Sagittal Vertical Axis (SVA) of +10 cm, Pelvic Incidence (PI) of 60 degrees, Lumbar Lordosis (LL) of -30 degrees, and Pelvic Tilt (PT) of 35 degrees. She has failed extensive conservative management.

Based on these radiographic parameters, what is the most appropriate surgical goal to restore optimal sagittal alignment?

. Achieve an SVA of < 5 cm.
. Match LL to PI (PI-LL < 10 degrees).
. Correct pelvic tilt to < 20 degrees.
. Increase LL to > 60 degrees.
. Reduce SVA by at least 15 cm.

Correct Answer & Explanation

. Match LL to PI (PI-LL < 10 degrees).

Explanation

The patient presents with significant sagittal malalignment, characterized by a large positive SVA (+10 cm), increased Pelvic Tilt (35 degrees), and a substantial mismatch between Pelvic Incidence (PI) and Lumbar Lordosis (LL) (PI-LL = 60 - 30 = 30 degrees). For adult spinal deformity, a key surgical goal for optimal sagittal balance is to achieve an LL that is closely matched to the PI, specifically aiming for a PI-LL mismatch of < 10 degrees. This ensures that the spine can efficiently balance the trunk over the pelvis. While an SVA < 5 cm is generally desired, and reducing pelvic tilt is part of overall correction, the PI-LL mismatch is a primary driver of sagittal malalignment and a critical parameter for surgical planning. Simply increasing LL to > 60 degrees without considering PI is insufficient. Reducing SVA by 15 cm is a consequence of proper PI-LL correction, not the primary strategic goal for planning.

Question 3260

Topic: 6. Spine

A 2-year-old child is diagnosed with progressive early-onset scoliosis (EOS) with a main thoracic curve measuring 45 degrees, unresponsive to bracing. The child has significant truncal imbalance and documented respiratory compromise. What is the MOST appropriate surgical management strategy for this patient?

. Posterior spinal fusion with instrumentation.
. Observation with serial radiographs until skeletal maturity.
. Growing rod surgery (e.g., magnetically controlled growing rods).
. Vertebral body tethering (VBT).
. Hemi-epiphysiodesis.

Correct Answer & Explanation

. Growing rod surgery (e.g., magnetically controlled growing rods).

Explanation

For a 2-year-old child with progressive early-onset scoliosis (EOS) and significant respiratory compromise, posterior spinal fusion is contraindicated as it arrests spinal growth and thoracic volume development, worsening pulmonary function. Observation is inappropriate for progressive curves with respiratory compromise. Growing rod surgery, such as magnetically controlled growing rods (MCGRs) or traditional growing rods, is the most appropriate surgical management. These techniques allow for continued spinal growth while controlling the curve, thus preserving and promoting thoracic volume and lung development. VBT is typically used for older children (often Risser 0-2) with idiopathic scoliosis to modulate growth, but it's less suitable for very young children with significant growth remaining and severe curves. Hemi-epiphysiodesis is used for smaller curves with significant growth potential, but not typically for a 45-degree curve at 2 years old.

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