AAOS & ABOS Spine Surgery MCQs: Trauma & Scoliosis

Question 1

Figures 25a and 25b show the radiograph and MRI scan of a 48-year-old man who reports increasing unsteadiness in his gait and hand clumsiness. Examination reveals a positive Hoffmann's reflex bilaterally, positive clonus, and a spastic gait. Management should consist of

Explanation

The patient has a congenitally small spinal canal with secondary multilevel degenerative changes causing stenosis and cord compression across multiple segments, including directly posterior to the vertebral bodies. A multilevel diskectomy may address the cord compression at the disk level, but not posterior to the bodies, and most likely would be inadequate. The patient has significant stenosis distal to C5, necessitating a more extensive surgical approach than simply C3-C5. Because the patient's cervical lordosis is preserved, a posterior procedure such as laminoplasty or laminectomy would allow the cord to fall away from the anterior pathology and afford decompression. Cervical myelopathy does not tend to resolve, and there is a significant risk for progression; therefore, surgical management usually is recommended. Edwards CC II, Riew KD, Anderson PA, et al: Cervical myelopathy: Current diagnostic and treatment strategies. Spine J 2003;3:68-81.

Question 2

Lumbar disk replacement has been shown to offer which of the following results?

Explanation

There is no clear evidence that disk replacement results in pain relief that is superior to fusion. Pain relief appears to be equivalent with these two procedures. No study has clearly demonstrated that normal segmental motion has been consistently restored. Preexisting facet arthropathy is considered to be a contraindication to disk replacement. Comparative long-term data demonstrating a reduced incidence of adjacent segment disease compared to fusion are not yet available. Geisler FH, Blumenthal SL, Guyer RD, et al: Neurological complications of lumbar artificial disc replacement and comparison of clinical results with those related to lumbar arthrodesis in the literature. J Neurosurg Spine 2004;1:143-154.

Question 3

When performing the exposure for an anterior approach to the cervical spine, the surgical dissection should not enter the plane between the trachea and the esophagus and excessive retraction should be avoided to prevent injury to the

Explanation

The recurrent laryngeal nerve lies between the trachea and the esophagus. The vagus nerve lies in the carotid sheath. The sympathetic trunk lies anterior to the longus colli muscles. The hypoglossal and superior laryngeal nerves are both at risk during the exposure but are not located between the trachea and the esophagus. Flynn TB: Neurologic complications of anterior cervical interbody fusion. Spine 1982;7:536-539.

Question 4

A 39-year-old man reports low back pain, lower extremity numbness, and urinary retention after being injured in a motor vehicle accident 1 day ago. He is able to walk but is in pain. A straight leg raise results in increased back pain, and examination reveals that perianal sensation is decreased. Placement of a urinary catheter results in 500 mL of urine. What is the next most appropriate step in management?

Explanation

Acute cauda equina syndrome, including saddle hypesthesia and bowel/bladder incontinence, is a red flag that demands emergent evaluation with MRI and urgent surgery if compression is confirmed. Results appear to be improved if surgery is performed within 48 hours. The other treatment approaches listed are not indicated if a cauda equina syndrome is present. Ahn UM, Ahn NU, Buchowski JM, et al: Cauda equina syndrome secondary to lumbar disc herniation: A meta-analysis of surgical outcomes. Spine 2000;25:1515-1522. Shapiro S: Medical realities of cauda equina syndrome secondary to lumbar disc herniation. Spine 2000;25:348-351.

Question 5

Figures 26a and 26b show the radiograph and MRI scan of an 18-year-old man who fell from a trampoline. Examination reveals exquisite local tenderness at the thoracolumbar junction, but he is neurologically intact. Management should consist of

Explanation

Based on the radiographic findings of marked disruption of the posterior ligamentous complex with a relatively small anterior bony fracture, the patient has a classic Chance-type ligamentous flexion-distraction injury. The pathology is mostly in soft tissues with limited healing potential. The treatment of choice is posterior reconstruction of the tension band with a short segment fusion with instrumentation. Casting or bracing may result in a painful kyphosis with ligamentous insufficiency. The anterior bony column is mostly intact, so anterior reconstruction is not necessary. Carl AL: Adult spine trauma, in DeWald RL (ed): Spinal Deformities: A Comprehensive Text. New York, NY, Thieme, 2003, pp 406-423.

Question 6

A 17-year-old high school football player is seen for follow-up after sustaining an injury 3 days ago. He reports that he tackled a player, felt numbness throughout his body, and could not move for approximately 15 seconds. A spinal cord injury protocol was initiated on the field. Evaluation in the emergency department revealed a normal neurologic examination and full painless neck motion. He states that he has no history of a similar injury. An MRI scan of the cervical spine is normal. During counseling, the patient and his family should be informed that he has sustained

Explanation

The long-term effect of transient quadriplegia is unknown. Based on a history of one brief episode of transient quadriplegia and normal examination and MRI findings, the risk of permanent spinal cord injury with a return to play is low. There is a risk of recurrent episodes of transient quadriplegia after the initial episode. Morganti C, Sweeney CA, Albanese SA, et al: Return to play after cervical spine injury. Spine 2001;26:1131-1136. Odor JM, Watkins RG, Dillin WH, et al: Incidence of cervical spinal stenosis in professional and rookie football players. Am J Sports Med 1990;18:507-509. Torg JS, Naranja RJ Jr, Palov H, et al: The relationship of developmental narrowing of the cervical spinal canal to reversible and irreversible injury of the cervical spinal cord in football players. J Bone Joint Surg Am 1996;78:1308-1314.

Question 7

Which of the following is considered a contraindication to cement injection techniques, such as kyphoplasty or vertebroplasty, in the treatment of osteoporotic compression fractures?

Explanation

When retropulsion of the posterior vertebral wall is present, nothing prohibits the cement from following the path of least resistance into the canal or from pushing a bone fragment further into the canal; most clinicians consider it a contraindication to these techniques. Patient age itself is not a contraindication as long as there are no medical contraindications to surgery. An acute fracture in a patient who remains immobile and hospitalized because of pain may be a good indication for such a technique. Prior compression fracture and older compression fractures are not contraindications, but pain relief may be less predictable. Phillips FM, Pfeifer BA, Leiberman IH, et al: Minimally invasive treatment of osteoporotic vertebral compression fractures: Vertebroplasty and kyphoplasty. Instr Course Lect 2003;52:559-567. Truumees E, Hilibrand A, Vaccaro AR: Percutaneous vertebral augmentation. Spine J 2004;4:218-229.

Question 8

Chronic anterior donor site pain following the harvest of autologous iliac crest bone graft for use during anterior cervical diskectomy and fusion is reported by approximately what percent of patients?

Explanation

Four years after surgery, more than 90% of patients are satisfied with the cosmetic appearance of the iliac donor site scar. Approximately 25% still have pain and/or functional difficulty, including 12.7% who still report difficulty with ambulation, 11.9% difficulty with recreational activities, 7.5% with sexual intercourse, and 11.2% require pain medication for iliac donor site symptoms. Silber JS, Anderson DG, Daffner SD, et al: Donor site morbidity after anterior iliac crest bone harvest for single-level anterior cervical discectomy and fusion. Spine 2003;28:134-139.

Question 9

When treating osteoporosis with alendronate, what is the most common side effect?

Explanation

Alendronate is a second-generation bisphosphonate, and it can cause epigastric distress in up to 30% of patients. This side effect can be minimized by gradually building up to therapeutic doses over a period of 4 to 8 weeks. Marshall JK, Rainsford KD, James C, et al: A randomized controlled trial to assess alendoronate-associated injury of the upper gastrointestinal tract. Aliment Pharmacol Ther 2000;14:1451-1457.

Question 10

Figures 27a and 27b show the radiographs of a 32-year-old woman who was involved in a high-speed motor vehicle accident. She is neurologically intact. After stabilization and assessment, treatment should consist of

Explanation

The radiographs show a fracture-dislocation with translation in both the coronal and sagittal planes, evidence of significant instability requiring surgical stabilization. Anterior instrumentation is not as effective as posterior instrumentation in restoring stability, and because there is little bony destruction, the anterior column can be successfully reconstructed with simple realignment. The treatment of choice is multisegment posterior fusion with instrumentation. Lewandrowski KU, McLain RF: Thoracolumbar fractures: Evaluation, classification, and treatment, in Frymoyer JW, Wiesel SW (eds): The Adult and Pediatric Spine. Philadelphia, PA, Lippincott Williams and Wilkins, 2004, pp 817-843.

Question 11

Figures 28a through 28c show the MRI scans of a 30-year-old woman who weighs 290 lb and has low back and left leg pain. She also reports frequent urinary dribbling, which her gynecologist has advised her may be related to obesity. Examination will most likely reveal

Explanation

The patient will most likely exhibit ipsilateral weakness of the tibialis anterior. Gaenslen's test is designed to detect sacroiliac inflammation as a source of low back pain. Beevor's sign tests the innervation of the rectus abdominus and paraspinal musculature (L1 innervation). The extensor hallucis longus is predominantly innervated by L5. The peroneals are predominantly innervated by S1. Hoppenfeld S: Physical Examination of the Spine and Extremities. Appleton, WI, Century-Crofts, 1976.

Question 12

Which of the following statements regarding conus medullaris syndrome is most accurate?

Explanation

Conus medullaris syndrome most frequently occurs as a result of trauma or with a disk herniation at L1, resulting in a lower motor neuron syndrome but with a poor prognosis for recovery of bowel and bladder dysfunction. The conus region, as the termination of the spinal cord, contains the motor cell bodies of the sacral roots. The syndrome is usually a sacral level neural injury; therefore, lower extremity weakness is uncommon. Haher TR, Felmly WT, O'Brien M: Thoracic and lumbar fractures: Diagnosis and management, in Bridwell KH, Dewald RL, Hammerberg KW, et al (eds): The Textbook of Spinal Surgery, ed 2. New York, NY, Lippincott Williams & Wilkins, 1977, pp 1773-1778.

Question 13

Which of the following factors has the greatest effect on the pull-out strength of a lumbar pedicle screw?

Explanation

All of the factors listed contribute to some extent to the pull-out strength of lumbar pedicle screws, but bone mineral density correlates most precisely. Wittenberg RH, Shea M, Swartz DE, et al: Importance of bone mineral density in instrumented spine fusions. Spine 1991;16:647-652.

Question 14

An inverted radial reflex is associated with

Explanation

An inverted radial reflex is a hypoactive brachioradialis reflex in combination with involuntary finger flexion. It is a spinal cord "release" sign and is associated with upper motor neuron pathology as seen in cervical stenosis with myelopathy. Radiculopathy is characterized by a diminished reflex but no finger flexion. Peripheral neuropathy is not associated with any reflex change. Parsonage-Turner syndrome is an idiopathic brachial neuritis. Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Williams & Wilkins, 1998, p 762.

Question 15

Figures 29a and 29b show the radiograph and CT scan of a 48-year-old man who has diffuse spinal pain. What is the most likely diagnosis?

Explanation

The studies show marginal syndesmophyte formation characteristic of ankylosing spondylitis. These patients typically have diffuse ossification of the disk space without large osteophyte formation. DISH typically presents with large osteophytes, referred to as nonmarginal syndesmophytes. In this patient, the zygoapophyseal joints are fused rather than degenerative as would be seen in rheumatoid arthritis, and the costovertebral joints are also fused. Osteopetrosis does not normally ankylose the disk space. McCullough JA, Transfeldt EE: Macnab's Backache, ed 3. Baltimore, MD, Williams and Wilkins, 1997, pp 190-194.

Question 16

The cervical disk herniation shown in the MRI scans in Figures 30a and 30b will most likely create which of the following constellations of symptoms?

Explanation

The MRI scans reveal a right-sided C5-6 herniated nucleus pulposus. A disk herniation in this region encroaches on the C6 root and is accompanied by a sensory change along the thumb and index finger, alterations in the brachioradialis reflex, and possible wrist extension weakness. Although the nerve root associated with the vertebral body passes above the pedicles such that the C6 root passes above the C6 pedicle, it is still the C6 root that is encroached on because the herniation affects the exiting root rather than the traversing root as seen in the lumbar spine. Klein JD, Garfin SR: Clinical evaluation of patients with suspected spine problems, in Frymoyer JW (ed): Adult Spine: Principles and Practice, ed 2. Philadephia, PA, Lippincott-Raven, 1997, pp 319-330.

Question 17

A 21-year-old man has had posterior neck discomfort for the past 6 months. A whole-body bone scan and a cervical single-photon emission CT reveal increased activity at the C7 spinous process. MRI reveals multifocal involvement of the spinous process lamina and facet of C7. A CT-directed needle biopsy reveals osteoblastoma. What is the best course of action?

Explanation

En bloc excision is the recommended treatment of osteoblastoma. Treatment should consist of en bloc removal of the lamina, facet, and spinous process. Facet removal would necessitate fusion. Radiation therapy is not recommended. Intralesional curettage has a high rate of recurrence. Bridwell KH, Ogilvie JW: Primary tumors of the spine, in Bridwell KH, DeWald RL (eds): The Textbook of Spinal Surgery. Philadelphia, PA, JB Lippincott, 1991, vol 2, pp 1143-1174.

Question 18

What is the most likely consequence of a vertebral compression fracture associated with osteoporosis?

Explanation

After an osteoporotic vertebral compression fracture, the risk of subsequent fractures at adjacent levels increases. This is felt to be the result of a shifting of the sagittal alignment more anteriorly, putting more stress on the osteopenic vertebral bodies and their anterior cortices. Pain generally resolves with rest, but this may take weeks or months. It has been demonstrated experimentally that osteoporotic vertebral bodies are actually less stiff and weaker after a compression fracture; therefore, deformity predisposes to further deformity. The extensor musculature often fatigues over time and usually does not hypertrophy. Frontal plane deformity is a rare development. Heaney RP: The natural history of vertebral osteoporosis: Is low bone mass an epiphenomenon? Bone 1992;13:S23-S26.

Question 19

What is the most appropriate treatment for a chordoma involving the sacrum?

Explanation

Chordomas are very radio- and chemotherapy resistant; therefore, en bloc resection with a negative margin is the preferred treatment. Lesions at or below S3 can be resected without compromising pelvis stability, and continence usually is maintained. The mean survival rate for patients with sacral chordomas is approximately 7 years. Patients with chordoma of the mobile (cervical, thoracic, or lumbar) spine have a mean survival rate of approximately 5 years. This difference is most likely the result of an earlier diagnosis. Fardin DF, Garfin SR, Abitbol J, et al (eds): Orthopaedic Knowledge Update: Spine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 123-133. Stener B, Gunterberg B: High amputation of the sacrum for extirpation of tumors: Principles and technique. Spine 1978;3:351-366.

Question 20

A 62-year-old woman has back pain and right L2 radicular pain. MRI scans suggest a neoplastic lesion at L2, and a bone scan is negative except at L2. History reveals that she was treated for breast cancer without known metastatic disease 12 years ago and is thought to be free of disease. What is the next most appropriate step in management?

Explanation

Because of the long disease-free interval, it cannot be assumed that this is breast cancer. The lesion could represent metastasis from a new primary tumor or could itself be a primary tumor. CT-guided biopsy will most effectively identify the lesion and guide treatment options. Depending on the specific diagnosis, any of the other options may be appropriate.

Question 21

A 60-year-old woman with rheumatoid arthritis has atlanto-axial instability and basilar invagination. What MRI findings would suggest the need for cervical fusion?

Explanation

The cervical medullary junction should be 135 degrees or greater. An angle of 125 degrees suggests compression of the cervical medullary junction. Other findings supporting surgical intervention include a cord diameter in flexion of less than 6 mm or less than 13 mm of space available for the cord. Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Williams & Wilkins, 1998, pp 700-701. Monsey RB: Rheumatoid arthritis of the cervical spine. J Am Acad Orthop Surg 1997;5:240-248.

Question 22

Which of the following statements is most accurate regarding undetected intraoperative surgical glove perforation?

Explanation

The incidence of undetected intraoperative surgical glove perforation has been demonstrated at approximately 8.5%, occurring most frequently on the index finger or left hand of the assistant surgeon. The frequency of glove perforation is higher in surgeries lasting longer than 3 hours. Al-Habdan I, Sadat-Ali M: Glove perforation in pediatric orthopaedic practice. J Pediatr Orthop 2003;23:791-793.

Question 23

Which of the following is NOT considered a risk factor for nonunion of a type II odontoid fracture?

Explanation

Although obesity can make brace or halo wear difficult, it has not been associated with an increased risk for nonunion. Carson GD, Heller JG, Abitbol JJ, et al: Odontoid fractures, in Levine AM, Eismont FJ, Garfin SR, et al (eds): Spine Trauma. Philadelphia, PA, WB Saunders, 1998, pp 235-238.

Question 24

A 27-year-old woman has a bilateral C5-C6 facet dislocation and quadriparesis after being involved in a motor vehicle accident. Initial management consisted of reduction with traction, but she remains a Frankel A quadriplegic. To facilitate rehabilitation, surgical stabilization and fusion is planned. From a biomechanical point of view, which of the following techniques is the LEAST stable method of fixation?

Explanation

In two different biomechanical studies performed in both bovine and human cadaveric spines, all posterior techniques of stabilization were found to be superior to anterior plating in flexion-distraction injuries of the cervical spine. These injuries usually have an intact anterior longitudinal ligament that allows posterior fixation to function as a tension band. Anterior plating with grafting destroys this last remaining stabilizing structure and does not allow for a tension band effect because all of the posterior stabilizing structures have been destroyed with the injury. In clinical practice, however, anterior plating can be effective in the treatment of this injury with appropriate postoperative orthotic management. Sutterlin CE III, McAfee PC, Warden KE, et al: A biomechanical evaluation of cervical spine stabilization methods in a bovine model: Static and cyclical loading. Spine 1988;13:795-802.

Question 25

Which of the following findings is considered a poor prognostic factor for postoperative neurologic recovery in patients with rheumatoid arthritis?

Explanation

When markedly diminished space available for the cord (demonstrated by a posterior atlantoaxial interval of less than 10 mm) is seen, there is a poor prognosis for recovery (25% of Ranawat class IIIb patients) following surgery. A posterior atlantoaxial interval of 14 mm or less is a predictor of increased risk of paralysis, but patients with an interval between 10 mm and 14 mm have a greater chance of recovery. Space available for the cord that is at least 14 mm is not associated with an increased risk of neurologic deficit. Boden SD, Dodge LD, Bohlman HH, et al: Rheumatoid arthritis of the cervical spine: A long-term analysis with predictors of paralysis and recovery. J Bone Joint Surg Am 1993;75:1282-1297.

Question 26

A 65-year-old man presents with progressive hand clumsiness and gait instability. MRI reveals 4-level cervical stenosis with a fixed kyphotic deformity of 15 degrees. What is the most appropriate surgical approach?

Explanation

In the setting of multi-level cervical myelopathy with a fixed kyphosis, an anterior approach (often combined with posterior) is required to adequately decompress the cord and correct the deformity. Posterior-only procedures like laminoplasty or laminectomy and fusion rely on lordosis for the cord to drift backward, which is ineffective in kyphotic spines.

Question 27

When evaluating an adult patient for a long-segment spinal fusion for degenerative scoliosis, which of the following spino-pelvic parameters correlates most strongly with postoperative health-related quality of life (HRQOL)?

Explanation

Sagittal vertical axis (SVA) is a primary driver of disability in adult spinal deformity; an SVA < 50 mm correlates closely with improved HRQOL. While PI-LL mismatch and PT are also important, SVA is the most widely validated global sagittal alignment predictor of outcomes.

Question 28

A 24-year-old man is brought to the ED after an MVA. He is awake, alert, and complains of severe neck pain with weakness in his right biceps. CT scan shows a right-sided C5-C6 unilateral facet dislocation. What is the most appropriate next step in management?

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation, closed reduction with skeletal traction should be attempted first to rapidly decompress the nerve root or cord. MRI is indicated prior to reduction only in patients who are uncooperative, intoxicated, or obtunded.

Question 29

During the physical examination of a 55-year-old woman with suspected cervical spondylotic myelopathy, tapping the brachioradialis tendon results in spontaneous flexion of the digits without flexion of the elbow. This finding indicates compression at which of the following spinal levels?

Explanation

The inverted radial reflex is a classic sign of an upper motor neuron lesion below C5 and a lower motor neuron lesion at C5. It is highly specific for spinal cord compression at the C5-C6 level.

Question 30

Which of the following is considered a significant risk factor for the development of proximal junctional kyphosis (PJK) following long-segment instrumented fusion for adult spinal deformity?

Explanation

Over-correction of lumbar lordosis and massive acute changes in sagittal alignment pre- to post-op increase the risk of PJK. Older age, osteopenia, and stopping the construct at the thoracolumbar junction (T10) are also well-documented risk factors.

Question 31

A 30-year-old woman sustains an L1 burst fracture after a fall. She is neurologically intact. MRI demonstrates an intact posterior ligamentous complex. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is her total score and the recommended treatment?

Explanation

The TLICS score assigns points for morphology (burst = 2), neurologic status (intact = 0), and posterior ligamentous complex integrity (intact = 0). A total score of 2 points strongly indicates nonoperative management (e.g., bracing) is recommended.

Question 32

A 72-year-old man falls forward, striking his chin. He presents with profound weakness in his hands and arms, but is able to ambulate with assistance. Perianal sensation is intact. What is the most likely pathophysiological mechanism of his injury?

Explanation

This is a classic presentation of central cord syndrome, which typically occurs in elderly patients with pre-existing cervical spondylosis who sustain a hyperextension injury. The spinal cord is compressed between anterior osteophytes and a buckling posterior ligamentum flavum.

Question 33

A 40-year-old driver involved in a high-speed collision sustains a traumatic spondylolisthesis of C2 (Hangman's fracture). Imaging shows greater than 3 mm of displacement and severe angulation of C2 on C3. What is the mechanism of this specific injury pattern (Levine-Edwards Type IIA), and what is a contraindication in its management?

Explanation

A Levine-Edwards Type IIA Hangman's fracture is caused by flexion-distraction and is characterized by severe angulation with minimal initial translation. Cervical traction is strictly contraindicated as it can over-distract the highly unstable discoligamentous injury and cause severe neurologic deficit.

Question 34

In long-segment fusions extending to the pelvis for adult degenerative scoliosis, Sacral-2 Alar-Iliac (S2AI) screws are often utilized instead of traditional iliac screws. Which of the following is an advantage of S2AI screws?

Explanation

S2AI screws have a starting point medial to traditional iliac screws, placing them directly in-line with the S1 and lumbar pedicle screws. This eliminates the need for bulky offset connectors, requires less lateral dissection, and significantly reduces hardware prominence.

Question 35

A 25-year-old man sustains a C6 spinal cord injury. He has no motor function below the level of injury but has preserved pinprick sensation in the perianal area and voluntary anal contraction. How is his injury classified according to the ASIA Impairment Scale (AIS)?

Explanation

An ASIA B (sensory incomplete) injury is characterized by the preservation of sensory function (including sacral segments S4-S5) but no motor function below the neurological level of injury. The presence of perianal sensation and anal contraction confirms sacral sparing.

Question 36

A 65-year-old woman presents with worsening back pain and an inability to stand up straight. Radiographs show adult degenerative scoliosis. Her pelvic incidence (PI) is 55 degrees, pelvic tilt (PT) is 30 degrees, and sacral slope (SS) is 25 degrees. To achieve optimal sagittal balance postoperatively, her lumbar lordosis (LL) should be reconstructed to approximately:

Explanation

For optimal sagittal balance, the lumbar lordosis (LL) should be matched to the pelvic incidence (PI) within 10 degrees (PI - LL < 10 degrees). Since her PI is 55 degrees, reconstructing LL to approximately 55 degrees perfectly matches the required spinopelvic parameters and minimizes the risk of adjacent segment failure.

Question 37

A 65-year-old man undergoes a C3-C6 laminectomy and posterior spinal fusion for severe cervical myelopathy. On postoperative day 2, he develops profound new-onset weakness of right shoulder abduction and elbow flexion, but sensory examination remains normal. What is the most likely etiology of this deficit?

Explanation

C5 nerve root palsy is a known complication of posterior cervical decompression, occurring in up to 10% of patients. It is most commonly attributed to the posterior shift of the spinal cord resulting in tethering or stretching of the relatively short C5 nerve root.

Question 38

A 55-year-old Asian male presents with progressive hand clumsiness and an unsteady gait. Imaging demonstrates multi-level ossification of the posterior longitudinal ligament (OPLL) causing severe cervical canal stenosis. Which of the following preoperative findings is an absolute contraindication to a posterior laminoplasty?

Explanation

Posterior cervical laminoplasty relies on the dorsal shift of the spinal cord away from anterior compressive pathology. Significant cervical kyphosis prevents this dorsal shift, making it a contraindication for laminoplasty, thus requiring an anterior or combined approach.

Question 39

A 72-year-old man with known cervical spondylosis falls forward, striking his forehead. He presents with severe weakness in his hands and arms (1/5 strength) but is able to move his legs against gravity (3/5 strength). What is the classic pathophysiologic mechanism for this specific pattern of neurologic deficit?

Explanation

This describes central cord syndrome, which classically occurs following a hyperextension injury in a stenotic cervical canal. The upper extremities are more severely affected than the lower extremities due to injury to the central gray matter and the medially located cervical motor fibers in the corticospinal tracts.

Question 40

In adult spinal deformity surgery, achieving optimal sagittal balance is critical to improving health-related quality of life outcomes. Which of the following sets of spinopelvic parameters represents the universally accepted SRS-Schwab postoperative target?

Explanation

The SRS-Schwab criteria for optimal sagittal alignment in adult spinal deformity include an SVA less than 5 cm, a pelvic tilt less than 20 degrees, and a pelvic incidence minus lumbar lordosis (PI-LL) mismatch within 10 degrees. Achieving these targets correlates strongly with improved patient-reported outcomes.

Question 41

A 24-year-old man sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following a motor vehicle collision. Imaging shows severe angulation and distraction of the C2-C3 intervertebral space with minimal translation, and the facet joints are intact. Which of the following management steps is strictly contraindicated for this fracture pattern?

Explanation

This presentation is consistent with a Type IIA Hangman's fracture, characterized by a flexion-distraction injury causing severe angulation and disc space disruption. Cervical traction is strictly contraindicated as it will exacerbate the distraction and can lead to catastrophic spinal cord injury.

Question 42

A neurologically intact 34-year-old male presents after a motor vehicle collision with a bilateral C5-C6 facet dislocation. An urgent MRI reveals a massive, extruded herniated disc behind the C5 vertebral body. What is the most appropriate next step in management?

Explanation

In awake, neurologically intact patients with a bilateral facet dislocation and a large herniated disc, an anterior approach (ACDF) is recommended first. This prevents retropulsion of the herniated disc material into the spinal canal during reduction, which could cause catastrophic neurologic injury.

Question 43

When planning corrective surgery for adult degenerative scoliosis, restoring optimal sagittal balance is highly correlated with improved clinical outcomes. To achieve this, the lumbar lordosis (LL) should be corrected to closely match which pelvic parameter?

Explanation

Optimal sagittal alignment in adult spinal deformity is achieved when the lumbar lordosis is restored to within 9-10 degrees of the patient's pelvic incidence (PI = LL +/- 10 degrees). Pelvic incidence is a fixed morphologic parameter that dictates the required amount of lumbar lordosis.

Question 44

A 62-year-old man undergoes a C3-C6 posterior laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 2, he develops isolated profound weakness in his bilateral deltoid and biceps muscles, with no worsening of his long-tract signs. What is the most likely etiology of this complication?

Explanation

C5 nerve root palsy occurs in up to 12% of patients following extensive posterior cervical decompression. It is typically caused by posterior drift of the spinal cord, which stretches and tethers the short, horizontally oriented C5 nerve root.

Question 45

According to the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following findings is the strongest determinant indicating the need for operative stabilization of a thoracolumbar burst fracture?

Explanation

In the TLICS system, disruption of the posterior ligamentous complex (PLC) assigns 3 points and is a primary determinant of biomechanical instability. Combined with a burst morphology (2 points), it results in a score greater than 4, strongly indicating operative management.

Question 46

A 68-year-old woman presents with progressive clumsiness in her hands and frequent tripping. During her physical examination, you note an inability to actively maintain extension and adduction of her small and ring fingers. This clinical sign is known as:

Explanation

The finger escape sign is a manifestation of cervical myelopathy characterized by the inability to maintain the ulnar digits in full extension and adduction. It is caused by weakness of the intrinsic hand muscles.

Question 47

A 70-year-old female undergoes a T10 to Pelvis posterior instrumented fusion for adult spinal deformity. Six months later, she presents with severe back pain and progressive kyphosis centered at T9. Which of the following intraoperative factors is most strongly associated with the development of this specific complication?

Explanation

Proximal junctional kyphosis (PJK) is a frequent complication of long fusions. Iatrogenic disruption of the posterior ligamentous complex (supraspinous and interspinous ligaments, and joint capsules) at the upper instrumented vertebra (UIV) is a major risk factor for PJK.

Question 48

A 55-year-old man with a long history of severe ankylosing spondylitis falls from standing height. He presents to the emergency department with new, severe lower cervical neck pain but no neurologic deficits. Plain radiographs of the cervical spine show typical syndesmophytes but no apparent fracture. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at extremely high risk for highly unstable, occult spinal fractures, even after minor trauma. If plain films are negative or inconclusive, advanced imaging (CT or MRI) of the entire spine is mandatory.

Question 49

A 60-year-old Asian male presents with severe progressive cervical myelopathy. CT scan demonstrates a continuous mass of ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. Sagittal alignment is evaluated and determined to be "K-line negative" (fixed cervical kyphosis). What is the optimal surgical approach?

Explanation

In OPLL patients with a "K-line negative" cervical spine (kyphotic alignment or massive OPLL where the cord cannot drift backward), an anterior approach (such as corpectomy and fusion) is favored because it provides direct decompression and allows for correction of the sagittal deformity.

Question 50

When performing a long posterior instrumented fusion extending to the sacrum for adult degenerative scoliosis, which of the following is the strongest indication to extend fixation distally into the pelvis (e.g., iliac or S2AI screws)?

Explanation

Pelvic fixation is indicated when fusing to the sacrum in adult spinal deformity to prevent S1 screw pullout and construct failure. This is especially critical when the fusion extends above L3 or when significant sagittal plane correction is required.

Question 51

A 75-year-old man trips and falls forward, striking his chin. He develops acute weakness in his upper extremities (hands worse than shoulders) but maintains functional strength in his lower extremities. The pathophysiology of his neurologic deficit involves injury to which specific region of the spinal cord?

Explanation

This is a classic presentation of central cord syndrome, typically occurring after a hyperextension injury in a stenotic cervical spine. It causes edema or hemorrhage in the central gray matter and medial portions of the corticospinal tracts, disproportionately affecting the upper extremities.

Question 52

A 60-year-old man presents with progressive hand clumsiness, positive Hoffmann reflexes bilaterally, and a spastic gait. Radiographs demonstrate advanced multi-level spondylosis with a fixed cervical kyphosis of 15 degrees. What is the primary biomechanical reason an anterior surgical approach is favored over a posterior laminoplasty in this patient?

Explanation

In the setting of fixed cervical kyphosis, the spinal cord is draped over the anterior spondylotic pathology. Posterior decompression (laminectomy or laminoplasty) will fail to decompress the cord because it cannot drift backward away from the anterior compression.

Question 53

An 82-year-old male with severe COPD, chronic kidney disease, and congestive heart failure sustains a Type II odontoid fracture with 2 mm of posterior displacement after a ground-level fall. He is neurologically intact. What is the most appropriate management strategy for this frail patient?

Explanation

In elderly patients with multiple severe medical comorbidities and minimally displaced Type II odontoid fractures, a hard cervical collar is the treatment of choice. Surgical intervention and halo vest immobilization carry unacceptably high morbidity and mortality in this frail population.

Question 54

In evaluating a patient with adult spinal deformity and "flatback" syndrome (loss of lumbar lordosis), the body attempts to compensate to maintain an upright posture. Which radiographic finding represents a primary pelvic compensatory mechanism for positive sagittal malalignment?

Explanation

When a patient shifts into positive sagittal alignment due to a loss of lumbar lordosis, the primary pelvic compensatory mechanism is to retrovert the pelvis. This leads to a radiographically increased pelvic tilt (PT).

Question 55

A 25-year-old male is involved in a high-speed motor vehicle collision while wearing only a lap seatbelt. He is diagnosed with a flexion-distraction (Chance) fracture of L2. Which of the following associated injuries must be most carefully evaluated and ruled out?

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of these patients have concurrent intra-abdominal injuries, particularly perforations of hollow viscous organs (e.g., bowel).

Question 56

A 64-year-old man presents with progressive numbness in his hands and hyperreflexia in all four extremities. He reports mild gait unsteadiness but is able to walk independently without assistance and continues to work full-time as an accountant. According to the Nurick classification for cervical myelopathy, what grade is this patient?

Explanation

Nurick Grade 2 describes a patient with signs of spinal cord disease who has slight difficulty in walking but remains capable of full-time employment. Grade 1 involves signs of disease without gait difficulty, and Grade 3 involves difficulty walking that requires assistance.

Question 57

A 65-year-old man presents with progressive hand clumsiness, gait instability, and hyperreflexia. MRI shows multi-level cervical stenosis from C3-C6 with preserved cervical lordosis. He undergoes a C3-C6 laminoplasty. Which of the following is the most common postoperative neurological complication specific to this procedure?

Explanation

C5 palsy is a well-documented complication following cervical posterior decompression, particularly laminoplasty or laminectomy. It occurs in 5-10% of cases due to posterior spinal cord shift and subsequent tethering of the short C5 nerve roots.

Question 58

An obtunded 35-year-old polytrauma patient is in the ICU following a high-speed collision. A high-quality fine-cut CT of the cervical spine with sagittal and coronal reconstructions is interpreted as completely normal by a senior radiologist. What is the most appropriate next step regarding cervical spine precautions according to current EAST guidelines?

Explanation

Current Eastern Association for the Surgery of Trauma (EAST) guidelines recommend removing the cervical collar in obtunded adult blunt trauma patients after a high-quality, negative cervical spine CT. MRI is no longer routinely required to clear the C-spine in this scenario.

Question 59

In a 68-year-old female presenting with adult degenerative scoliosis and severe sagittal imbalance, the goal of surgical reconstruction is to achieve a mismatch between Pelvic Incidence (PI) and Lumbar Lordosis (LL) of less than what value to optimize clinical outcomes?

Explanation

A PI-LL mismatch of less than 10 degrees is the widely accepted surgical target in adult spinal deformity correction. Achieving this restores physiological sagittal alignment, minimizes adjacent segment disease, and significantly improves health-related quality of life.

Question 60

A 55-year-old man of East Asian descent presents with signs of severe cervical myelopathy. Radiographs and CT reveal continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6 with a K-line negative alignment (kyphotic alignment). What is the most appropriate surgical approach?

Explanation

In K-line negative OPLL, the ossified mass crosses the line connecting the midpoints of the spinal canal at C2 and C7, typically due to local kyphosis. Posterior decompression alone is insufficient as the cord will not drift back; therefore, an anterior or combined anterior-posterior decompression is required.

Question 61

A 25-year-old man sustains a severe fracture-dislocation at T10 following a motor vehicle collision. On examination in the trauma bay, he has no motor or sensory function below the umbilicus, absent rectal tone, and an absent bulbocavernosus reflex. What is the clinical significance of the absent bulbocavernosus reflex?

Explanation

The absence of the bulbocavernosus reflex indicates spinal shock, a state of transient physiological areflexia following spinal cord trauma. A definitive ASIA classification of the injury cannot be established until spinal shock resolves, which is signaled by the return of this reflex.

Question 62

A 72-year-old female with a 45-degree adult degenerative lumbar scoliosis complains primarily of severe, neurogenic claudication in both legs after walking one block. She denies significant mechanical back pain. MRI shows severe L3-L4 and L4-L5 central and lateral recess stenosis. What is the most appropriate initial surgical management?

Explanation

In adult degenerative scoliosis presenting primarily with claudication and minimal deformity-related axial pain, localized decompression with short-segment fusion is indicated. Fusion is added to prevent rapid destabilization and progression of the curve at the decompressed levels.

Question 63

During the evaluation of a 60-year-old patient with suspected cervical myelopathy, you perform the Hoffmann test. A positive response consists of reflex flexion of the interphalangeal joint of the thumb and distal interphalangeal joint of the index finger. This reflex arc is primarily mediated by which spinal cord level?

Explanation

The Hoffmann reflex indicates upper motor neuron dysfunction above the level of the hand. The reflex arc involves the finger flexors, which are primarily innervated by the C8 nerve root via the median nerve.

Question 64

A 68-year-old man with known cervical spondylosis falls forward and strikes his chin. He develops bilateral upper extremity weakness (hands significantly worse than shoulders) with relatively preserved lower extremity motor function. Which of the following best explains the pathophysiologic mechanism of this specific syndrome?

Explanation

Central cord syndrome classically results from a hyperextension injury in a patient with a pre-existing stenotic cervical canal. The central gray matter and the medially situated cervical fibers of the corticospinal tract are preferentially contused, leading to disproportionate upper extremity weakness.

Question 65

A 28-year-old male sustains a hyperflexion-rotation injury to his neck. Radiographs show less than 25% anterior subluxation of C5 on C6. He is awake and cooperative, exhibiting a right-sided C6 radiculopathy but no signs of myelopathy. What is the most appropriate initial management step?

Explanation

In an alert, cooperative patient with a unilateral facet dislocation and a radicular deficit, urgent closed reduction with awake cervical traction is the standard of care. Pre-reduction MRI is unnecessary in patients who can reliably participate in serial neurologic exams during traction.

Question 66

A 62-year-old male with severe fixed global sagittal malalignment (SVA = +15 cm) undergoes spinal reconstructive surgery. The surgeon plans a Pedicle Subtraction Osteotomy (PSO) at L3. Approximately how many degrees of lordosis can be expected from a single-level lumbar PSO?

Explanation

A Pedicle Subtraction Osteotomy (PSO) is a three-column closing wedge osteotomy that hinges on the anterior longitudinal ligament. It typically provides between 25 and 35 degrees of lordotic correction at a single level.

Question 67

A 45-year-old woman presents with progressive weakness and muscle wasting in both hands, accompanied by fasciculations. She also reports difficulty walking. Examination shows hyperreflexia in the lower extremities but absent reflexes in the upper extremities. Sensation is completely intact throughout. What is the most likely diagnosis?

Explanation

The combination of upper motor neuron signs (lower extremity hyperreflexia) and lower motor neuron signs (hand wasting, fasciculations, areflexia) with absolutely intact sensation is the classic presentation of ALS. Cervical myelopathy almost always presents with some degree of sensory impairment.

Question 68

A 65-year-old female presents with severe back pain and an inability to stand up straight. Which of the following radiographic parameters correlates most strongly with poor health-related quality of life (HRQOL) scores in adult spinal deformity?

Explanation

Sagittal vertical axis (SVA) is a critical measure of global sagittal balance. A positive SVA > 5 cm correlates most strongly with pain, disability, and poor HRQOL in adult spinal deformity patients.

Question 69

A 55-year-old male presents with progressive cervical myelopathy secondary to ossification of the posterior longitudinal ligament (OPLL). On a lateral neutral cervical radiograph, the OPLL mass crosses the K-line. What is the most appropriate surgical approach?

Explanation

A negative K-line (where the OPLL mass crosses the K-line) indicates poor cervical lordosis and significant anterior compression. Posterior decompression alone is insufficient as the cord will not adequately drift posteriorly, making an anterior or combined approach necessary.

Question 70

A 35-year-old male sustains a fall. CT shows a burst fracture of L1 with 40% canal compromise. He is neurologically intact, and MRI confirms the posterior ligamentous complex (PLC) is intact. What is his Thoracolumbar Injury Classification and Severity (TLICS) score and recommended management?

Explanation

The TLICS score is 2: morphology is burst (2 points), neurology is intact (0 points), and PLC is intact (0 points). A score of 3 or less is typically treated nonoperatively with a brace.

Question 71

A 68-year-old man with underlying cervical spondylosis sustains a hyperextension injury. He presents with profound upper extremity weakness, relatively preserved lower extremity strength, and intact perianal sensation. This syndrome is most accurately characterized by injury to which portion of the spinal cord?

Explanation

Central cord syndrome occurs classically from hyperextension in a stenotic cervical spine. It preferentially damages the central gray matter and the medial aspect of the corticospinal tracts, which topographically represent the upper extremities.

Question 72

In preoperative planning for a 60-year-old patient with flatback syndrome and adult degenerative scoliosis, the surgeon aims to restore ideal sagittal balance. To achieve optimal postoperative alignment, the lumbar lordosis (LL) should be within how many degrees of the pelvic incidence (PI)?

Explanation

Based on the Schwab criteria for adult spinal deformity, optimal sagittal alignment is achieved when the patient's lumbar lordosis is restored to within 10 degrees of their pelvic incidence (PI - LL < 10 degrees).

Question 73

A 50-year-old male presents with painless, progressive weakness and muscle atrophy of his bilateral upper extremities. He has hyperreflexia in the lower extremities but intact sensation throughout. EMG reveals widespread fasciculations and denervation in multiple myotomes. What is the most likely diagnosis?

Explanation

Amyotrophic lateral sclerosis (ALS) mimics cervical myelopathy by presenting with mixed upper and lower motor neuron signs. However, the strict absence of sensory deficits and widespread EMG abnormalities point to ALS.

Question 74

A 25-year-old male is involved in a high-speed MVA. He is awake, cooperative, but has complete paralysis below C6. Radiographs show a C5-C6 bilateral facet dislocation. What is the most appropriate next step in management?

Explanation

In an awake, cooperative patient with a cervical facet dislocation and a neurologic deficit, rapid closed reduction using cranial traction with serial exams is the standard of care to urgently decompress the spinal cord prior to MRI.

Question 75

A 16-year-old female wearing a lap belt is involved in a head-on collision. Radiographs demonstrate a horizontal fracture through the spinous process, pedicles, and vertebral body of L2. Which of the following associated injuries must be aggressively ruled out?

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt restraints. They carry an association with intra-abdominal injuries, particularly hollow viscus injuries (e.g., bowel perforation), in up to 50% of cases.

Question 76

Proximal junctional kyphosis (PJK) is a recognized complication following long segment fusions for adult spinal deformity. Which of the following factors most significantly increases the risk of developing PJK?

Explanation

Significant postoperative over-correction of the sagittal plane shifts the center of gravity abnormally, heavily stressing the adjacent segments and predisposing to PJK. Hook fixation and preserving posterior ligaments are actually protective.

Question 77

A 30-year-old male presents after an MVA. CT shows a bilateral pars interarticularis fracture of C2 with 4 mm of anterior displacement and 15 degrees of angulation. According to the Levine and Edwards classification, what type of fracture is this, and what is the primary mechanism of injury?

Explanation

A Type II Hangman's fracture features >3 mm translation and significant angulation. The classic mechanism is initial hyperextension and axial loading followed by a severe rebound flexion.

Question 78

During the physical examination of a 62-year-old male with progressive gait difficulty, the examiner quickly flicks the nail of the patient's middle finger downward, resulting in reflexive flexion of the thumb and index finger. This clinical sign is indicative of:

Explanation

This describes a positive Hoffmann sign, which suggests an upper motor neuron lesion (cervical myelopathy) typically located above the C8 level.

Question 79

The recurrent laryngeal nerve is at greatest risk during an anterior approach to the lower cervical spine on the right side due to its unique anatomic course. Where does the right recurrent laryngeal nerve loop before ascending into the neck?

Explanation

The right recurrent laryngeal nerve loops around the right subclavian artery and has a more variable, non-longitudinal oblique course compared to the left side. This anatomy makes it significantly more susceptible to injury during right-sided anterior cervical approaches.

Question 80

A 68-year-old woman with adult degenerative scoliosis presents with severe back pain and a forward stooped posture. Standing full-length radiographs reveal a sagittal vertical axis (SVA) of +12 cm. To achieve optimal sagittal balance postoperatively, surgical correction should aim for a relationship between Pelvic Incidence (PI) and Lumbar Lordosis (LL) of:

Explanation

In the surgical management of adult spinal deformity, achieving a Pelvic Incidence to Lumbar Lordosis (PI-LL) mismatch of less than 10 degrees is highly correlated with improved postoperative health-related quality of life. This alignment helps restore physiological sagittal balance and minimizes the sagittal vertical axis.

Question 81

A 30-year-old construction worker falls from a scaffolding, sustaining an L1 burst fracture. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) system, what is his total score and the recommended management?

Explanation

The TLICS system assigns points for morphology (burst = 2), neurological status (intact = 0), and PLC integrity (intact = 0). A total score of 2 strongly suggests nonoperative management, whereas scores of 5 or greater warrant surgical intervention.

Question 82

A 72-year-old man with a history of severe cervical spondylosis falls forward, striking his chin. He presents with profound weakness in his bilateral hands and arms, but retains functional motor strength in his legs. Perianal sensation and sphincter tone are intact. Which of the following best describes the anatomical basis for his neurological deficit?

Explanation

This classic presentation represents Central Cord Syndrome, typically caused by a hyperextension injury in a stenotic cervical spine. The upper extremity motor tracts are located medially within the lateral corticospinal tract, making them more susceptible to central cord edema and injury than the laterally positioned lower extremity tracts.

AAOS Orthopedic MCQs (Set 1): Spine Disorders, Sports Medicine & Arthroplasty | 2026 Board Review

AAOS & ABOS Spine Surgery MCQs (Set 4): Spinal Trauma, Cervical Myelopathy & Adult Scoliosis

Key Takeaway

AAOS & ABOS Spine Surgery MCQs (Set 4): Spinal Trauma, Cervical Myelopathy & Adult Scoliosis

Chapter Index