Orthopedic Spine MCQs 2026 | Board Review & Answers

Question 1

A patient with myelopathy underwent a one-level corpectomy 1 day ago and is now home. In the middle of the night he calls to report markedly increased difficulty in swallowing, diaphoresis, a change in his voice, and difficulty lying flat. What is the best course of action?

Explanation

The patient has respiratory distress as manifested by his difficulty in lying flat. In addition, the diaphoresis and the change in his voice indicate retropharyngeal edema or hematoma that is compressing his larynx. The only appropriate treatment is hospital admission and elective intubation. During intubation it is possible to cause laryngospasm in a patient with a hyperacute airway; therefore, the surgeon should be prepared to perform a cricothyroidotomy. Often a fiberoptically guided intubation is the only way to find the airway in the presence of retropharyngeal edema or hematoma. Emery SE, Smith MD, Bohlman HH: Upper-airway obstruction after multilevel cervical corpectomy for myelopathy. J Bone Joint Surg Am 1991;73:544-551.

Question 2

Figure 10 shows the radiograph of an 18-year-old woman who sustained a spinal cord injury in a motor vehicle accident. Based on the radiographic findings, her injury is best described as

Explanation

The Allen and Ferguson mechanistic classification system is a useful tool for evaluating cervical spine injuries. Cervical fractures are classified as compressive extension, distractive extension, compressive flexion, distractive flexion, vertical compression, and lateral flexion. The patient has a distractive flexion injury.

Question 3

Examination of a 30-year-old professional singer who has persistent neck and shoulder pain reveals a positive Hoffman's sign and clonus because of anterior C2-3 cord compression. The MRI scan shown in Figure 11a and the cervical CT scan shown in Figure 11b reveal focal anterior cord compression at the C2-3 level. Which of the following surgical approaches would least affect her professional career?

Explanation

11b Protection of the superior laryngeal nerve is critical in a professional singer. The nerve is easily injured with retraction when using vertical extension of common anterior surgical approaches to gain exposure to the C2-3 level. McAfee and associates reported on 17 patients with C1-2 and C2-3 pathology. They used a modified submandibular approach as an anterior retropharyngeal exposure with modification of the superior extension of the Smith-Robinson technique that allows visualization of the superior laryngeal nerve and surrounding structures. No incidences of superior laryngeal nerve injury were recorded. The transoral approach should be avoided because of the high rate of infection and limited exposure. McAfee PC, Bohlman HH, Reilly LH Jr, Robinson RA, Southwick WO, Nachlas NE: The anterior retropharyngeal approach to the upper part of the cervical spine. J Bone Joint Surgery Am 1987;69:1371-1383.

Question 4

Figure 12 shows the lumbar CT scan of a 24-year-old man who was injured in a snowmobile accident. What is the mechanism of injury?

Explanation

A true compression fracture is a single-column injury that does not create canal compromise. A burst fracture is a two- or three-column injury that disrupts the middle column and thereby narrows the spinal canal. This patient has a burst fracture. The mechanism of injury is usually vertical compression or flexion compression. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 197-217.

Question 5

Which of the following changes occur in the spinal cord and the spinal canal when the cervical spine moves from neutral to full flexion?

Explanation

The spinal cord and spinal canal undergo dynamic changes during neck flexion and extension. In neck flexion, the spinal cord initially unfolds and then undergoes elastic deformation with full flexion; the spinal canal lengthens. This may explain the presence of Lhermitte's sign as the cord is pulled anteriorly over an anterior osteophyte or disk, generating a compressive force on the spinal cord. During neck extension, the spinal cord relaxes (folding like an accordion) and the spinal canal shortens. Breig A: Biomechanics of the Central Nervous System: Some Basic Normal and Pathologic Phenomena. Stockholm, Sweden, Almquist and Wiksell, 1960.

Question 6

A patient who was involved in a motor vehicle accident 2 days ago now reports neck pain. He denies any other symptoms. Radiographs reveal a type II odontoid fracture that is 2 mm anteriorly displaced. Management consists of halo vest immobilization in extension, and repeat radiographs reveal that the fracture is completely reduced. The patient is discharged to home, but later that evening he notes difficulty swallowing while trying to eat dinner. What is the most likely cause of this difficulty?

Explanation

If the neck is immobilized in excessive extension, it can be difficult for the patient to swallow. If the patient had injured the recurrent or superior laryngeal nerve at the time of the accident, it is likely to have manifested itself earlier on. Esophageal trauma or retropharyngeal edema or hematoma from the fracture also should have manifested itself earlier. Because the fracture was completely reduced, it is unlikely that moving the small fragment posteriorly would have injured the esophagus. Garfin SR, Botte MJ, Waters RL, Nickel VL: Complications in the use of halo fixation device. J Bone Joint Surg Am 1986;68:320-325.

Question 7

A 64-year-old man who underwent an L4-5 decompression approximately 1 year ago reported relief of his claudicatory leg pain initially, but he now has increasing low back pain and recurrent neurogenic claudication despite nonsurgical management. Radiographs show new asymmetric collapse and spondylolisthesis at the decompressed segment, and MRI scans show lateral recess stenosis. The next most appropriate step in management should consist of

Explanation

When radiographic findings reveal postlaminectomy instability, procedures that do not include some type of fusion will fail to solve the problem. In fact, wider decompression or diskectomy alone will only further destabilize the segment. Because there is radiographic evidence of recurrent lateral recess stenosis and symptomatic neurogenic claudication, a revision decompression should be included. Since access to the canal involves a posterior approach, the stabilization should be performed through that same approach. Herkowitz HN, Kurz LT: Degenerative lumbar spondylolisthesis with spinal stenosis: A prospective study comparing decompression with decompression and intertransverse process arthrodesis. J Bone Joint Surg Am 1991;73:802-808.

Question 8

A patient who was involved in a motor vehicle accident 2 weeks ago now reports neck pain. Work-up reveals no evidence of nerve root involvement or acute radiographic abnormality. The patient appears to have a hyperextension soft-tissue injury of the neck (whiplash). What is the best course of treatment at this time?

Explanation

Early mobilization and resumption of normal activities immediately after neck sprain has been shown to improve functional outcome and decrease subjective symptoms as measured 6 months after injury. Borchgrevink GE, Kaasa A, McDonagh D, Stiles TC, Haraldseth O, Lereim I: Acute treatment of whiplash neck injuries: A randomized trial during the first 14 days after a car accident. Spine 1998;23:25-31.

Question 9

A 19-year-old man has had back pain with activity, especially running in soccer and baseball, for the past 4 months. He denies any history of trauma. Examination reveals no motor weakness or sensory changes in the lower extremities. Range of motion shows increased pain with extension and mild limitation with flexion. A sitting straight leg raising test is limited at approximately 60 degrees bilaterally by back and buttocks pain. Plain radiographs are normal. MRI scans are shown in Figures 13a through 13e. What is the most likely diagnosis?

Explanation

13b 13c 13d 13e The patient has an isthmic spondylolysis. The plain radiographs are normal, but the MRI scans show increased marrow edema and signal at the L5 pars interarticularis. Findings of bilateral hamstring tightness and increased pain with extension over flexion suggests spondylolysis. The MRI scans do not show any signs of the other conditions. Wiltse LL, Rothman SL: Spondylolisthesis: Classification, diagnosis and natural history. Sem Spine Surg 1993;5:264-280.

Question 10

A neurologic injury at T11-L2 with loss of bowel and bladder control is best described as what syndrome?

Explanation

Conus medullaris syndrome describes isolated loss of bowel and bladder function, usually at T12-L1 but can include T11-L2. In central cord syndrome, lower extremity motor function is better than upper extremity function. 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. In anterior cord syndrome, the 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 11

The space available for the cord is an important determinant in neurologic recovery. Recent analysis suggests that the most reliable radiographic predictor for neurologic recovery after surgery in patients with rheumatoid arthritis and paralysis is a preoperative

Explanation

Boden and associates' recent article presents significant evidence that patients with rheumatoid arthritis, neurologic deterioration, and C1-2 instability are more likely to improve after surgery if the posterior alanto-odontoid interval is greater than 10 mm preoperatively. The accepted safe range for the posterior atlanto-odontoid interval is 14 mm. This measurement is believed to better represent the space available for the cord than the anterior alanto-odontoid interval. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 273-279. Boden SD, Dodge LD, Bohlman HH, Rechtine GR: 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 12

A 21-year-old woman with scoliosis reports no pain, and her examination is unremarkable except for the scoliosis. Preoperative radiographs, including bending views, are shown in Figures 14a through 14e. The thoracic curve measures 62 degrees. Treatment should consist of

Explanation

14b 14c 14d 14e The patient has a King type III curve with a very flexible lumbar spine that derotates and levels well on side bending. The fractional upper thoracic curve is also quite flexible and will not need to be addressed; therefore, treatment should consist of posterior spinal fusion from T4 to L1. An anterior spinal fusion at the very apex of the curve will not address the curve satisfactorily, and an approach across the diaphragm provides little benefit in this patient. King HA, Moe JH, Bradford DS, Winter RB: The selection of fusion levels in thoracic idiopathic scoliosis. J Bone Joint Surg Am 1983;65:1302-1313.

Question 13

Figure 15 shows possible locations of anterior pin sites for halo fixation. What location is considered most ideal?

Explanation

The anterior pin should be placed just above and lateral to the eyebrow at the site labeled A. At site B, the supraorbital nerve can be damaged. At site C, the supratrochlear nerve or the frontal sinus can be damaged. The site labeled D is over the temporalis muscle; in this location the temple bone is thin and there is the risk of perforation. Site E is above the equator of the forehead; at this location there is a risk that the halo ring will slip off the head altogether. Garfin SR, Botte MJ, Waters RL, Nickel VL: Complications in the use of halo fixation device. J Bone Joint Surg Am 1986;68:320-325.

Question 14

A 30-year-old man requires surgical stabilization of a hypermobile spondylolisthesis of L5 on S1. History reveals that he has smoked one pack of cigarettes a day for 15 years. During preoperative counseling, the patient should be advised to

Explanation

Many studies have shown the negative effects of cigarette smoking on the success of lumbar arthrodesis. Some have suggested preoperative cessation is a significant factor for good results. However, Deguchi and associates, in a review of spondylolisthesis fusions, and Glassman and associates, in a review of scoliosis fusions, showed no significant benefit from preoperative cessation of smoking. In every report, however, postoperative smoking correlated with a significantly increased rate of pseudarthrosis. Cessation of smoking with the use of nicotine substitutes would not be beneficial because animal studies and human clinical trials have shown that nicotine is a major factor in failure of fusion in patients who continue to smoke. Silcox DH III, Daftari T, Boden SD, Schimandle JH, Hutton WC, Whitesides TE Jr: The effect of nicotine on spinal fusion. Spine 1995;20:1549-1553. Deguchi M, Rapoff AJ, Zdeblick TA: Posterolateral fusion for isthmic spondylolisthesis in adults: Analysis of fusion rate and clinical results. J Spinal Disord 1998;11:459-464.

Question 15

What is the most likely type of pathology seen in Figure 16?

Explanation

The figure shows the missing pedicle or "winking owl" sign that is characteristic of tumor involvement of the cortical bone of the pedicle. None of the other pathologic processes commonly gives this radiographic picture. Thinned, but not missing pedicles, have been described as a normal variant. McLain R, Weinstein J: Tumors of the spine, in Herkowitz HH (ed): The Spine, ed 4. Philadelphia, PA, WB Saunders, 1992, p 1173.

Question 16

In a retroperitoneal approach to the lumbar spine, what nerve is commonly found on the psoas muscle?

Explanation

The genitofemoral nerve and the sympathetic plexus consistently lie on the ventral surface of the psoas muscle. The ilioinguinal and iliohypogastric nerves are the most superior branches of the lumbar plexus and emerge along the upper lateral border of the psoas muscle traveling toward the quadratus lumborum. Both the obturator and femoral nerves are deep and lateral to the psoas muscle. Watkins RG (ed): Surgical Approaches to the Spine, ed 1. New York, NY, Springer-Verlag, 1983, p 107. Johnson R, Murphy M, Southwick W: Surgical approaches to the spine, in Herkowitz HH (ed): The Spine, ed 4. Philadelphia, PA, WB Saunders, 1992, p 1559.

Question 17

A 21-year-old man has had posterior neck discomfort for the past 6 months. Radiographs, an MRI scan, and a photomicrograph of the biopsy specimen are shown in Figures 17a through 17d. What is the most likely diagnosis?

Explanation

17b 17c 17d Forty percent of osteoblastomas occur in the spine, and they can become large and locally aggressive lesions. They generally occur in the posterior elements but can occur in the ribs and transverse processes. Microscopic analysis of the lesion will reveal hyperchromatic osteoblasts separated by incompletely mineralized bars of bone. Recommended treatment is en bloc excision. Fibrous dysplasia, giant cell tumor, and hemangioma can have similar radiographic appearances; therefore, biopsy may be required to differentiate them from more aggressive lesions. Osteochondromas are characterized by an osteocartilaginous growth arising from the cortex. 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

An otherwise healthy 16-year-old boy who has had thoracolumbar pain with an increasingly worse deformity for the past 2 years now reports that the pain is worse at night. He responded well to nonsteroidal anti-inflammatory drugs initially, but they have become less effective. He denies any neurologic or constitutional symptoms. Examination is consistent with a mild thoracolumbar scoliosis and is otherwise normal. Laboratory studies show a normal CBC, erythrocyte sedimentation rate, and C-reactive protein. Standing radiographs show a 20 degree left thoracolumbar scoliosis, and he has a Risser stage of 4. A bone scan shows increased uptake at L2; a CT scan through this level is shown in Figure 18. Management should now consist of

Explanation

The findings and radiographic appearance are most consistent with osteoid osteoma involving the medial pedicle. Scoliosis is commonly seen with this lesion and usually does not need surgical intervention. Excellent results have been reported with surgical excision as well as with percutaneous thermocoagulation. Nonsurgical treatment also has been described in peripheral osteoid osteoma but is not well described for lesions within the spine. Cove JA, Taminiau AH, Obermann WR, Vanderschueren GM: Osteoid osteoma of the spine treated with percutaneous computed tomography-guided thermocoagulation. Spine 2000;25:1283-1286. Kneisl JS, Simon MA: Medical management compared with operative treatment for osteoid-osteoma. J Bone Joint Surg Am 1992;74:179-185.

Question 19

Which of the following assessment tools most accurately reflects outcomes of well-being, daily function, and general health in a patient treated for cervical myelopathy?

Explanation

The short-form 36 is an excellent tool for measuring the patient's perception of treatment outcome because it is a patient-generated, validated assessment of physical, social, and role function, emotional and mental health, energy/fatigue, pain, health perception, and health change. The Nurick criteria is an evaluation of physical function with gradations of ambulation and daily function. The Japanese Orthopaedic Association score gives points for function in activities of daily living but does not assess perception of general health. The neck disability index assesses the impact of neck pain on daily life, and the Odom criteria are the surgeon's evaluations of degree of radicular pain and deficit. Albert TJ, Mesa JJ, Eng K, McIntosh TC, Balderston RA: Health outcome assessment before and after lumbar laminectomy for radiculopathy. Spine 1996;21:960-963. Swiontkowski MF, Buckwalter JA, Keller RB, Haralson R: The outcomes movement in orthopaedic surgery: Where we are and where we should go. J Bone Joint Surgery Am 1999;81:732-740.

Question 20

A 54-year-old man undergoes uneventful anterior cervical diskectomy and interbody fusion at C4-5 for focal disk herniation and C5 radiculopathy. At the 3-week follow-up examination, the patient reports a persistent cough. Pulmonary evaluation reveals a mild but persistent aspiration. Laryngoscopy reveals partial paralysis of the left vocal cord, most likely caused by

Explanation

The exact anatomic event responsible for vocal cord paralysis associated with anterior cervical surgery remains a question. Apfelbaum and associates, in an excellent review of 900 anterior cervical surgeries, identified 30 patients with vocal cord paralysis, 3 of which were permanent. They showed that retractors placed under the longus coli for anterior cervical exposures can compress the laryngeal-tracheal branches within the larynx against the tented endotracheal tube rather than the recurrent laryngeal nerve, which is extrinsic to the larynx. By releasing the endotracheal cuff and allowing the tube to recenter itself after placement of the retractors, they were able to decrease vocal cord injury from 6.4% to 1.7%. Jewett and associates suggested that a left-sided approach may result in a lower incidence of injury. Endotracheal intubation is the second most common cause of vocal cord injury, with an incidence of approximately 2%. Apfelbaum RI, Kriskovich MD, Haller JR: On the incidence, cause, and prevention of recurrent laryngeal nerve paralysis during anterior cervical spine surgery. Spine 2000;25:2906-2912.

Question 21

A 32-year-old professional football player has disabling left arm pain in the C7 dermatome that has been increasing in severity for the past 2 months. Examination shows a positive Spurling test on the left side, but no changes in motor, sensory, or deep tendon reflexes. Because nonsurgical management has failed to provide relief, he has chosen surgery to allow him to complete his season. The MRI scan and myelogram shown in Figures 19a and 19b show minimal disk bulge, but a root cutoff is noted at the left C7 foramen. Electromyography demonstrates C7 nerve root irritation. Which of the following procedures will best optimize his chances for completing the season?

Explanation

19b Because the patient has chronic pain, a possible lateral recess stenosis of the C7 root, and no neurologic deficits, keyhole foraminotomy is the treatment of choice for decompressing the exiting nerve root and offering an early return to play, especially when using a muscle-splitting posterior approach. Henderson and associates reported excellent results with posterolateral foraminotomy in patients with radicular symptoms. Although anterior cervical diskectomy and fusion is equally effective in the long term, a period of 6 to 12 weeks is required to allow the anterior fusion to heal prior to a return to play. Chen and associates reported that keyhole foraminotomy maintains cervical motion segment dynamics better than compared to anterior limited diskectomy and foraminotomy or anterior diskectomy with fusion. Henderson, CM, Hennessy RG, Shuey HM Jr, Shackelford EG: Posterior-lateral foraminotomy as an exclusive operative technique for cervical radiculopathy: A review of 846 consecutively operated cases. Neurosurgery 1983;13:504-512. Dillin W, Booth R, Cuckler J, Balderston R, Simeone F, Rothman R: Cervical radiculopathy: A review. Spine 1986;11:988-991.

Question 22

The majority of severe cervical spine injuries occurring in contact sports evolve during axial loading and flexion of the cervical spine. At what minimum degree of flexion does axial loading place the cervical spine at risk during contact sports?

Explanation

The paravertebral musculature, the intervertebral disks, and the normal lordotic curvature of the cervical spine can absorb much of the imparted energy of collision. However, when the neck is flexed approximately 30 degrees, the normal lordotic curvature is flattened and the forces applied to the vertex of the head are directed at a straight segmented column. In this situation, the cervical spine is less able to absorb the applied force. With mounting axial load, compressive deformation occurs within the intervertebral disks, causing angular deformation and buckling. The spine will fail in flexion, with resultant fracture, subluxation, or dislocation. A rotatory component added to axial compression can cause concomitant extension, rotation, and shear injury patterns. The National Football Head and Neck Injury Registry has made two recommendations to the NCAA Football Rules Committee to minimize the risk of such injuries: (1) No player should intentionally strike an opponent with the crown or top of the helmet; and (2) No player should deliberately use his helmet to butt or ram an opponent. Thomas BE, McCullen GM, Yuan HA: Cervical spine injuries in football players. J Am Acad Orthop Surg 1999;7:338-347.

Question 23

According to the Third National Acute Spinal Cord Injury Study (NASCIS 3), what is the recommended protocol for a patient who sustained a spinal cord injury 7 hours ago?

Explanation

NASCIS 2 established the recommended doses of methylprednisolone for spinal cord injury. This included an initial bolus of 30 mg/kg over 1 hour, followed by an infusion of 5.4 mg/kg/h for an additional 23 hours. If the injury was more than 8 hours old, the methylprednisolone was not recommended. NASCIS 3 changed the dosing schedule based on the time from injury. If the time from injury to treatment was less than 3 hours, the standard protocol was followed (30 mg/kg bolus followed by 5.4 mg/kg/h for 23 hours). If the time from injury to treatment was between 3 and 8 hours, the infusion was continued at 5.4 mg/kg for an additional 23 hours (48 hours total). In this situation with a time of injury 7 hours ago, treatment should consist of a bolus and further steroid therapy for 48 hours. Bracken MB, Shepard MJ, Holford TR, et al: Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury: Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study. JAMA 1997;277:1597-1604.

Question 24

Lumbar instability may be surgically induced by

Explanation

In cadaveric studies, unilateral facetectomy, or excision of 50% or more of both facets, significantly decreases the biomechanic integrity of the motion segment and may increase the risk of iatrogenic instability. Sacrifice of the spinous process, interspinous ligaments, and ligamentum flavum weakens the motion segment but does not increase the risk for instability. Facetectomy, even unilateral, predisposes the patient toward lumbar instability.

Question 25

A 19-year-old man who sustained a spinal cord injury in a motor vehicle accident 3 days ago has 5/5 full strength in the deltoids and biceps bilaterally, 4/5 strength in wrist extension bilaterally, 1/5 triceps function on the right side, and 2/5 triceps function on the left side. The patient has no detectable lower extremity motor function. Based on the American Spinal Injury Association's classification, what is the patient's functional level?

Explanation

By convention when determining the motor level, the key muscle must be at least 3/5. The next most rostral level must be 4/5. Therefore, this patient's functional level is C6.

Question 26

A 45-year-old man presents to the emergency department with acute urinary retention, saddle anesthesia, and severe bilateral leg pain. MRI reveals a massive central disc herniation at L4-L5. Regarding the timing of surgical intervention, which of the following statements is most accurate?

Explanation

Cauda equina syndrome is a surgical emergency. Decompression within 24 to 48 hours of symptom onset is associated with significantly improved outcomes for bladder, bowel, and motor function compared to surgery performed after 48 hours.

Question 27

A 60-year-old man undergoes a C3-C6 posterior laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 1, he demonstrates profound weakness in his right deltoid and biceps (0/5) but has preserved hand grip and normal sensation. What is the most likely etiology of this new deficit?

Explanation

Postoperative C5 palsy is a known complication following cervical decompression (especially posterior laminectomy), presenting as deltoid and biceps weakness. It is thought to be caused by posterior shifting of the spinal cord resulting in traction on the short, tethered C5 nerve roots.

Question 28

A 55-year-old woman with a 20-year history of rheumatoid arthritis presents with progressive neck pain and hyperreflexia in her lower extremities. Flexion-extension radiographs demonstrate an Atlanto-Dental Interval (ADI) of 9 mm. There is no evidence of cranial settling. What is the most appropriate management?

Explanation

In rheumatoid arthritis, an ADI greater than 8-9 mm or the presence of neurologic symptoms (myelopathy) is an indication for C1-C2 posterior fusion. Occipitocervical fusion would be indicated if there were concurrent cranial settling (vertical subluxation).

Question 29

An 82-year-old man falls from a standing height and complains of severe neck pain. CT imaging reveals a Type II odontoid fracture with 2 mm of posterior displacement. His neurologic examination is normal. In considering non-operative management, which of the following strategies carries the highest risk of mortality in this patient population?

Explanation

Halo vest immobilization in elderly patients (especially those over 80 years old) is associated with unacceptably high morbidity and mortality rates due to respiratory complications and falls. A rigid cervical collar is generally preferred in this population despite a high nonunion rate.

Question 30

A 35-year-old woman falls from a horse and sustains a T12 burst fracture. She is neurologically intact. MRI demonstrates that the posterior ligamentous complex (PLC) is intact. Loss of vertebral body height is 30%, and local kyphosis is 15 degrees. Based on the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

Explanation

The patient's TLICS score is 2 (2 points for burst morphology, 0 for intact neurology, 0 for intact PLC). A TLICS score less than 4 is an indication for non-operative management, typically with a TLSO brace.

Question 31

A 45-year-old man presents with severe right anterior thigh pain, weakness in right knee extension, and a diminished right patellar reflex. MRI of the lumbar spine reveals a far lateral (extraforaminal) disc herniation at the L3-L4 level on the right. Which nerve root is most likely being compressed?

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at that level. Therefore, an L3-L4 far lateral disc compresses the L3 nerve root, while a paracentral disc at the same level would compress the traversing L4 root.

Question 32

A 50-year-old woman undergoes a C5-C6 anterior cervical discectomy and fusion via a right-sided approach. Postoperatively, she has a hoarse voice, and direct laryngoscopy confirms unilateral vocal cord paralysis. The nerve most likely injured in this approach courses between which two anatomic structures?

Explanation

The recurrent laryngeal nerve is vulnerable during anterior cervical approaches, particularly on the right side where its course is more variable. It normally ascends in the tracheoesophageal groove between the trachea and esophagus.

Question 33

A 65-year-old man with known cervical spondylosis is involved in a rear-end motor vehicle collision. He presents with severe bilateral upper extremity weakness (motor strength 2/5) but relatively preserved lower extremity strength (motor strength 4/5) and patchy sensory loss. Which of the following represents the typical expected recovery pattern for his neurologic condition?

Explanation

The patient has central cord syndrome, classically caused by a hyperextension injury in a stenotic cervical spine. Recovery typically occurs in a predictable sequence: lower extremities first, followed by bowel/bladder function, then proximal upper extremities, and finally distal upper extremity fine motor function.

Question 34

A 55-year-old intravenous drug user presents with severe midthoracic back pain, fevers, and rapidly progressive bilateral leg weakness over the past 24 hours. MRI demonstrates a dorsal epidural fluid collection at T8-T10 causing severe spinal cord compression. What is the most appropriate definitive management?

Explanation

A spinal epidural abscess presenting with an acute or progressive neurologic deficit is an absolute indication for urgent surgical decompression. A posterior approach (laminectomy) is typically used for dorsal collections.

Question 35

A 14-year-old girl is diagnosed with Adolescent Idiopathic Scoliosis. Upright radiographs demonstrate a main thoracic curve of 55 degrees and a lumbar curve of 35 degrees. On lateral bending films, the thoracic curve corrects to 40 degrees, and the lumbar curve corrects to 30 degrees. According to the Lenke classification system, what type of curve pattern does she have?

Explanation

This is a Lenke Type 3 (Double Major) curve. The main thoracic curve is structural (>25 degrees on bending), and the lumbar curve is also structural (fails to correct to <25 degrees on side bending).

Question 36

A 65-year-old woman presents with neurogenic claudication and localized low back pain. Radiographs demonstrate a Grade 1 degenerative spondylolisthesis at L4-L5 with dynamic instability on flexion-extension views. She has failed 6 months of non-operative management. According to long-term outcome studies, which surgical intervention provides the most durable outcome for this patient?

Explanation

For degenerative spondylolisthesis with dynamic instability and neurogenic claudication, decompression with instrumented fusion yields better long-term clinical outcomes and lower reoperation rates compared to decompression alone.

Question 37

A 60-year-old man with metastatic renal cell carcinoma to the T10 vertebra presents with intractable pain and early paraparesis. MRI shows epidural tumor with high-grade spinal cord compression. Given that renal cell carcinoma is radioresistant, what is the preferred treatment strategy prior to stereotactic body radiation therapy (SBRT)?

Explanation

Separation surgery involves circumferential decompression of the spinal cord to create a safe margin between the tumor and the neural elements, combined with posterior stabilization. This allows the safe delivery of high-dose, tumor-ablative SBRT to radioresistant tumors.

Question 38

A 55-year-old man undergoes a straightforward C3-C6 anterior cervical discectomy and fusion (ACDF). Three hours postoperatively in the PACU, he develops rapidly progressive quadriparesis and difficulty breathing. His drain output is minimal, but his neck is visibly swollen. What is the most appropriate next step in management?

Explanation

Postoperative retropharyngeal hematoma can cause rapid airway compromise and neurologic deficit. Immediate bedside opening of the wound to evacuate the hematoma is the lifesaving next step before returning to the OR.

Question 39

A 65-year-old man with a long-standing history of ankylosing spondylitis presents to the emergency department after a ground-level fall. He complains of severe lower neck pain but has no neurologic deficits. Plain radiographs of the cervical spine are obscured by the shoulders and appear unremarkable. What is the most appropriate next step in management?

Explanation

Patients with AS are highly susceptible to unstable fractures from low-energy trauma. Due to altered anatomy and osteopenia, radiographs are often inadequate; a CT scan is mandatory to rule out a highly unstable occult fracture.

Question 40

An 82-year-old woman sustains a Type II odontoid fracture after a fall. She is neurologically intact. Her past medical history is significant for severe COPD and congestive heart failure. Which of the following treatments is associated with the lowest morbidity and mortality for this patient?

Explanation

In elderly patients with significant comorbidities, surgical fixation and halo vest immobilization carry a high risk of morbidity and mortality. Rigid cervical collar immobilization is the safest initial treatment, accepting a higher rate of nonunion which is often asymptomatic.

Question 41

A 60-year-old man with severe cervical myelopathy undergoes a C3-C6 posterior laminectomy and fusion. Postoperatively, he has marked improvement in his lower extremity spasticity, but on postoperative day 2, he develops isolated profound weakness in right shoulder abduction and elbow flexion. There is no sensory loss. What is the most likely etiology of this new deficit?

Explanation

Postoperative C5 palsy is a known complication of cervical decompression, occurring most commonly due to posterior shift (drift) of the spinal cord and subsequent traction on the relatively short C5 nerve roots. It is typically self-limiting but may take months to recover.

Question 42

A 35-year-old man falls from a roof and sustains a T12 burst fracture. Neurologic examination reveals normal strength and sensation in the lower extremities (ASIA E). CT and MRI show 40% loss of anterior vertebral height, 15% canal compromise, and an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the recommended treatment?

Explanation

The TLICS score for this patient is 2 (Morphology: burst = 2, Neurologic status: intact = 0, PLC: intact = 0). A score of 3 or less is an indication for non-operative management, typically with a TLSO.

Question 43

A 62-year-old woman presents with worsening right C6 radiculopathy. Ten years ago, she underwent an uncomplicated C4-C5 anterior cervical discectomy and fusion (ACDF). Imaging now shows a solid fusion at C4-C5 and new, severe right-sided foraminal stenosis at C5-C6. What biomechanical factor most likely contributed to this pathology?

Explanation

Adjacent segment disease is thought to result from the natural history of cervical spondylosis coupled with increased biomechanical stress, intradiscal pressure, and compensatory hypermobility at the levels adjacent to a rigid fusion.

Question 44

A 58-year-old man with a history of prostate cancer presents with severe, mechanically exacerbated back pain. Imaging reveals a lytic metastatic lesion in the L2 vertebral body involving the left pedicle and 60% of the vertebral body height, with a resulting 15-degree kyphosis. He is neurologically intact. According to the SINS criteria, this lesion is considered:

Explanation

The Spinal Instability Neoplastic Score (SINS) assesses lesion location, pain, bone type, radiographic alignment, and posterolateral involvement. High scores (13-18) indicate severe instability warranting surgical stabilization prior to radiation.

Question 45

A 70-year-old man presents with neurogenic claudication. MRI shows severe L4-L5 central canal stenosis with a Grade 1 degenerative spondylolisthesis. Flexion-extension radiographs demonstrate 4 mm of dynamic translation. He has failed 6 months of conservative management. What is the most appropriate surgical intervention?

Explanation

In the setting of lumbar spinal stenosis with degenerative spondylolisthesis and dynamic instability (translation >3 mm), decompression alone has a high failure rate. Laminectomy combined with instrumented posterolateral fusion yields superior clinical outcomes.

Question 46

A 72-year-old man with pre-existing cervical stenosis experiences a hyperextension injury in a minor motor vehicle collision. He presents with bilateral upper extremity weakness (motor score 2/5 in hands) and relatively preserved lower extremity strength (motor score 4/5). He has hyperreflexia in the lower extremities. What is the most likely diagnosis?

Explanation

Central cord syndrome typically occurs after a hyperextension injury in an elderly patient with cervical spondylosis. It is characterized by disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 47

A 22-year-old man is involved in a high-speed motor vehicle collision while wearing only a lap seatbelt. He complains of severe back pain. CT of the lumbar spine reveals a fracture line extending horizontally through the spinous process, pedicles, and posterior vertebral body of L2. What associated injury must be actively ruled out?

Explanation

A Chance fracture is a flexion-distraction injury often associated with lap seatbelt use. It has a high association (up to 50%) with intra-abdominal injuries, particularly hollow viscus injuries like small bowel perforation.

Question 48

A 45-year-old intravenous drug user presents with progressive back pain, fever, and new-onset lower extremity weakness and urinary retention. His ESR and CRP are markedly elevated. MRI with gadolinium shows a large, peripherally enhancing fluid collection in the dorsal epidural space at T8-T10 compressing the spinal cord. What is the most appropriate next step in management?

Explanation

This patient has a spinal epidural abscess with acute neurologic deficit (weakness, urinary retention). Urgent surgical decompression (laminectomy and evacuation) is indicated to reverse or prevent permanent neurologic compromise.

Question 49

A 16-year-old boy presents with a prominent mid-thoracic hump and back pain. Standing lateral radiographs reveal a thoracic kyphosis of 65 degrees. There is anterior wedging of 8 degrees at three consecutive vertebrae, and Schmorl's nodes are visible. He has 1 year of remaining skeletal growth. What is the most appropriate initial treatment?

Explanation

The patient meets the criteria for Scheuermann's disease. Because he has remaining growth and a curve between 50-75 degrees, bracing (Milwaukee or TLSO) is the most appropriate treatment to halt curve progression.

Question 50

A 65-year-old man undergoes a posterior cervical laminectomy and fusion from C3-C6 for cervical spondylotic myelopathy. Postoperatively on day 1, he develops new-onset weakness in the deltoid and biceps (1/5) bilaterally, with intact sensation and no lower extremity changes. What is the most likely etiology?

Explanation

C5 palsy is a known complication of cervical decompression, occurring in up to 5-10% of cases, primarily due to nerve root tethering or reperfusion injury. It generally presents with motor weakness of the deltoid and biceps and has a good prognosis for spontaneous recovery.

Question 51

A 35-year-old man is brought to the ED after a motor vehicle collision. He is obtunded and intubated. Radiographs reveal a C5-C6 unilateral facet dislocation. What is the next best step in management?

Explanation

In an unexaminable or obtunded patient with a cervical facet dislocation, an MRI must be obtained prior to any reduction maneuvers. This is critical to evaluate for a herniated disc that could cause severe neurologic deterioration during reduction.

Question 52

A 72-year-old woman with a history of severe rheumatoid arthritis presents with neck pain and mild myelopathy. Radiographs demonstrate atlantoaxial instability. Which of the following radiographic measurements is the most reliable indicator of potential neurological compromise requiring surgical stabilization?

Explanation

The Posterior Atlantodens Interval (PADI), also known as the Space Available for the Cord (SAC), is the most reliable predictor of neurologic deficit in rheumatoid arthritis. A PADI of less than 14 mm is generally an absolute indication for surgical stabilization.

Question 53

A 45-year-old man presents with severe back pain and bilateral lower extremity weakness after a fall from a height. A CT scan shows an L1 burst fracture with 60% canal compromise. Examination reveals intact perianal sensation, but decreased rectal tone and urinary retention. Which of the following is the most appropriate management?

Explanation

The patient exhibits signs of cauda equina syndrome, giving him a high Thoracolumbar Injury Classification and Severity (TLICS) score. A TLICS score > 4, driven heavily by an incomplete neurological deficit, is a strong indication for urgent surgical decompression and stabilization.

Question 54

A 68-year-old man with a history of prostate cancer presents with progressively worsening back pain, which is worse at night. Thoracic spine MRI reveals an infiltrative lesion in the T8 vertebral body with posterior cortex destruction and mild epidural extension, but no cord compression. The neurological exam is intact. What is the most appropriate initial management?

Explanation

Metastatic prostate cancer is highly radiosensitive. Without signs of spinal cord compression or gross mechanical instability, localized radiation therapy is the standard first-line treatment for pain control and local tumor management.

Question 55

A 30-year-old construction worker presents with back pain after lifting a heavy beam. He reports pain radiating down the lateral aspect of his left leg to the dorsum of his foot, along with weakness in great toe extension. Which nerve root is most likely affected?

Explanation

Weakness in the extensor hallucis longus (great toe extension) and pain radiating to the dorsum of the foot are classic clinical signs of an L5 radiculopathy. This is most commonly caused by a paracentral L4-L5 disc herniation.

Question 56

A 50-year-old woman undergoes an uncomplicated L4-L5 microdiscectomy. On postoperative day 2, she complains of severe positional headaches that worsen when sitting upright and improve upon lying flat. Which of the following is the most appropriate initial management?

Explanation

Post-dural puncture headaches caused by an occult incidental durotomy are initially managed conservatively with bed rest, hydration, and caffeine. If conservative measures fail after several days, an epidural blood patch or surgical re-exploration may be considered.

Question 57

A 22-year-old male is involved in a high-speed motor vehicle collision. A CT scan of the cervical spine reveals a fracture through the pars interarticularis of C2 bilaterally, with severe angulation and anterior translation of C2 on C3. The C2-C3 disc space is widened anteriorly. Which of the following treatments is absolutely contraindicated?

Explanation

This presentation describes a Type IIA Hangman's fracture, which involves severe angulation secondary to a flexion-distraction injury mechanism. Cervical traction is strictly contraindicated as it can cause catastrophic over-distraction and subsequent spinal cord injury.

Question 58

A 60-year-old diabetic patient presents with 2 weeks of worsening back pain, fevers, and a recent onset of bilateral lower extremity weakness. Laboratory studies show elevated ESR and CRP. An MRI with contrast demonstrates an epidural fluid collection at L3-L4 with peripheral enhancement. What is the next best step in management?

Explanation

The patient has a spinal epidural abscess with progressive, acute neurological deficits. Urgent surgical decompression and debridement are required to prevent irreversible neurological damage, followed by targeted antibiotic therapy.

Question 59

A 12-year-old girl is diagnosed with adolescent idiopathic scoliosis. Her primary curve is a right thoracic curve of 55 degrees. When discussing surgical intervention with pedicle screw instrumentation, what is the most critical potential complication associated with a medial pedicle wall breach in the thoracic spine?

Explanation

A medial pedicle screw breach in the thoracic spine directly enters the spinal canal, placing the spinal cord at high risk for direct mechanical injury. Conversely, lateral breaches risk injury to the pleura, lungs, or great vessels.

Question 60

A 45-year-old man with ankylosing spondylitis presents with severe back pain after a low-energy fall. CT imaging demonstrates a displaced transvertebral fracture through T10. What is the most appropriate management for this patient?

Explanation

Spinal fractures in ankylosing spondylitis are highly unstable due to the rigid spine acting as a long lever arm. Long-segment posterior instrumented fusion is required to prevent displacement and pseudoarthrosis.

Question 61

An 82-year-old woman with severe COPD and heart failure falls and sustains a Type II odontoid fracture with 2 mm of displacement. What is the most appropriate initial management considering her comorbidities?

Explanation

In frail elderly patients with significant medical comorbidities, halo vest immobilization carries a high mortality and complication rate. A rigid cervical collar is the preferred initial management despite a higher risk of nonunion.

Question 62

A 55-year-old diabetic man presents with progressive bilateral leg weakness, urinary retention, and fever over the last 24 hours. MRI reveals a dorsal epidural abscess from T8 to T10 with severe spinal cord compression. What is the most urgent and appropriate intervention?

Explanation

Rapid neurological decline secondary to a dorsal spinal epidural abscess is a surgical emergency. Posterior laminectomy with abscess evacuation provides immediate decompression of the spinal cord.

Question 63

A 30-year-old man falls from a roof and sustains a T12 burst fracture. He is neurologically intact, and MRI confirms an intact posterior ligamentous complex. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his score and recommended management?

Explanation

The TLICS score assigns 2 points for a burst fracture, 0 points for intact neurology, and 0 points for an intact PLC. A total score of 2 is an indication for non-operative management.

Question 64

Which of the following findings is considered the most sensitive early clinical indicator for diagnosing Cauda Equina Syndrome?

Explanation

Urinary retention, often assessed by measuring post-void residual volume, is the most sensitive early clinical sign of Cauda Equina Syndrome. It typically precedes true incontinence, saddle anesthesia, and severe motor deficits.

Question 65

A 65-year-old man presents with progressive hand clumsiness, frequent falls, and a positive Hoffman's sign. MRI reveals multilevel cervical stenosis from C3-C6 with cord signal changes. Lateral radiographs show a neutral cervical sagittal alignment without instability. Which surgical approach is most appropriate?

Explanation

Cervical laminoplasty is ideal for multilevel spondylotic myelopathy in patients with neutral or lordotic alignment and no significant instability or severe axial neck pain. It indirectly decompresses the cord while preserving motion.

Question 66

A 60-year-old man with metastatic renal cell carcinoma presents with severe mechanical back pain and progressive lower extremity weakness. MRI demonstrates a T8 lytic lesion with high-grade epidural spinal cord compression. According to the NOMS framework, what is the most appropriate management?

Explanation

Renal cell carcinoma is radioresistant, making cEBRT ineffective for high-grade compression. The NOMS framework recommends separation surgery to decompress the cord, followed by SBRT to provide durable local tumor control.

Question 67

A 55-year-old man undergoes a 10-hour posterior spinal fusion for severe adult scoliosis. Upon awakening, he complains of bilateral painless vision loss, and his pupils are sluggish to react. What is the most likely etiology of his vision loss?

Explanation

Ischemic optic neuropathy is the most common cause of perioperative vision loss after prolonged spine surgery in the prone position. Risk factors include significant blood loss, prolonged hypotension, and long operative times.

Question 68

A 25-year-old man is involved in a motor vehicle collision. Imaging reveals a traumatic spondylolisthesis of the axis with bilateral C2 pars fractures, severe angulation, >5 mm translation, and bilateral C2-C3 facet dislocations. Based on the Levine-Edwards classification, what is the injury type and optimal treatment?

Explanation

This describes a Levine-Edwards Type III Hangman's fracture, characterized by C2 pars fractures with bilateral C2-C3 facet dislocations. It is highly unstable and requires open reduction and surgical stabilization.

Question 69

In the surgical planning for Adolescent Idiopathic Scoliosis using the Lenke classification, which curve type is defined specifically as a 'Double Major' curve?

Explanation

In the Lenke classification system, Lenke 3 is defined as a Double Major curve. This indicates both the Main Thoracic and Lumbar/Thoracolumbar curves are structural, but the Main Thoracic curve is larger.

Question 70

A 7-year-old girl presents with torticollis and her head tilted to the right and rotated to the left following an upper respiratory infection. Dynamic CT shows atlantoaxial rotatory subluxation with 4 mm of anterior displacement of C1 on C2. What is the Fielding and Hawkins classification of this injury?

Explanation

Fielding and Hawkins Type II atlantoaxial rotatory subluxation is characterized by unilateral anterior displacement of one lateral mass by 3-5 mm. This indicates a deficiency or rupture of the transverse ligament.

Question 71

Which of the following is an essential radiographic criterion for diagnosing Diffuse Idiopathic Skeletal Hyperostosis (DISH) according to Resnick?

Explanation

Resnick's criteria for DISH require flowing ossification of at least four contiguous vertebral bodies. It also requires preservation of intervertebral disc height and the absence of sacroiliac joint erosion or facet ankylosis.

Question 72

A 20-year-old man is brought to the trauma bay after sustaining a C5 burst fracture resulting in complete quadriplegia. He is noted to have a blood pressure of 80/50 mmHg, a heart rate of 50 bpm, and warm, flushed extremities. What is the primary pathophysiological mechanism for his hemodynamic state?

Explanation

The patient is experiencing neurogenic shock, caused by the loss of sympathetic outflow originating from T1-L2. This results in unopposed vagal tone, leading to the classic presentation of hypotension, bradycardia, and warm extremities.

Question 73

A 14-year-old gymnast has persistent back pain and radicular leg pain due to a Grade II L5-S1 isthmic spondylolisthesis. She has failed 6 months of conservative management including bracing and physical therapy. What is the most appropriate surgical intervention?

Explanation

In adolescents with a symptomatic Grade II isthmic spondylolisthesis that fails conservative treatment, posterior or transforaminal instrumented fusion is the standard of care. Pars repair is generally reserved for Grade 0 or I slips without disc degeneration.

Question 74

A 65-year-old man undergoes a C3-C6 laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 1, he develops isolated weakness in his right deltoid and biceps (2/5 strength), with normal strength elsewhere and no sensory deficits. What is the most appropriate initial management?

Explanation

C5 palsy is a known complication of cervical decompression, particularly laminectomy and fusion, due to posterior spinal cord shift and nerve root tethering. It is usually motor-dominant and self-limiting, with the vast majority of patients recovering full function through observation and physical therapy.

Question 75

A 68-year-old woman presents with severe low back pain and difficulty standing upright. Standing lateral radiographs reveal a pelvic incidence (PI) of 60 degrees and a lumbar lordosis (LL) of 30 degrees. To achieve optimal sagittal balance, what is the surgical target for her lumbar lordosis?

Explanation

In adult spinal deformity surgery, the primary goal is to correct the PI-LL mismatch to within 10 degrees (LL = PI +/- 10 degrees). For a PI of 60 degrees, a lumbar lordosis of approximately 50 to 60 degrees should be targeted to restore sagittal balance.

Question 76

A 45-year-old man undergoes an anterior lumbar interbody fusion (ALIF) at L5-S1. Postoperatively, he complains of cloudy urine and a lack of seminal emission during orgasm. Injury to which of the following structures is the most likely cause?

Explanation

Retrograde ejaculation following an L5-S1 ALIF is caused by iatrogenic injury to the superior hypogastric plexus, which provides sympathetic innervation to the internal urethral sphincter. Utilizing blunt dissection and avoiding monopolar electrocautery over the L5-S1 disc space minimizes this risk.

Question 77

A 55-year-old man with long-standing ankylosing spondylitis presents to the emergency department with neck pain after a low-speed motor vehicle collision. Neurologic examination is normal. Standard AP and lateral cervical radiographs are read as negative. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at an extremely high risk for unstable extension-distraction fractures even following minor trauma. Due to altered osseous anatomy and generalized osteopenia, standard radiographs are inadequate, making a CT scan of the entire cervical spine mandatory to rule out occult fractures.

Question 78

A 30-year-old man falls from a 10-foot ladder. CT reveals an L1 burst fracture with 40% canal compromise. MRI shows an intact posterior ligamentous complex (PLC). Neurologic exam is completely normal. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the recommended treatment?

Explanation

The TLICS score for this patient is 2: 2 points for burst fracture morphology, 0 points for an intact PLC, and 0 points for normal neurologic status. A total score of 3 or less indicates nonoperative management, typically with a rigid orthosis or early mobilization.

Question 79

A 50-year-old diabetic man presents with 3 days of worsening neck pain, fever, and new-onset clumsiness in his hands. Exam reveals weakness in bilateral hand intrinsics and hyperreflexia in the lower extremities. MRI reveals a ventral cervical epidural abscess extending from C3 to C6. What is the most appropriate definitive management?

Explanation

A ventral cervical epidural abscess causing acute myelopathy requires urgent surgical decompression. An anterior approach (corpectomy, debridement, and fusion) allows direct visualization and complete evacuation of the ventral pathology without manipulating the already compromised spinal cord.

Question 80

A 72-year-old man with known severe cervical stenosis falls forward and strikes his chin. He presents with profound weakness in his upper extremities (1/5) but preserved strength in his lower extremities (4/5). MRI shows cord signal change at C4-C5 without fracture or instability. If surgery is planned, what is the currently recommended timing for decompression?

Explanation

Acute traumatic central cord syndrome is increasingly treated with early surgical decompression. Recent evidence, such as the STASCIS trial, supports early intervention (within 24 hours) as it correlates with significantly better long-term neurologic recovery compared to delayed surgery.

Question 81

A 15-year-old male gymnast has severe lower back pain exacerbated by extension. Radiographs and MRI confirm a bilateral L5 spondylolysis without listhesis. He has failed 6 months of bracing and physical therapy. A diagnostic injection of the pars defect provides complete temporary relief. What is the most appropriate surgical treatment?

Explanation

In a young, highly active patient with symptomatic spondylolysis without listhesis who fails prolonged nonoperative management, direct pars repair is the procedure of choice. This technique stabilizes the defect while preserving normal lumbar motion segments.

Question 82

An 82-year-old woman with severe COPD presents with neck pain after a fall. CT demonstrates a displaced Type II odontoid fracture. Neurologic exam is normal. The decision is made to manage her nonoperatively with a rigid cervical collar rather than a halo vest. What is the primary reason to avoid halo vest immobilization in this specific patient?

Explanation

Halo vest immobilization in the elderly, particularly those with severe pulmonary comorbidities like COPD, is associated with a high incidence of morbidity and mortality due to restricted chest excursion, pneumonia, and respiratory failure. A rigid cervical collar is generally favored for nonoperative management in this demographic.

Question 83

A 14-year-old girl is undergoing posterior spinal fusion for a Lenke 1A adolescent idiopathic scoliosis. Her stable vertebra (SV) is L1, and the end vertebra (EV) is T12. How should the Lowest Instrumented Vertebra (LIV) be selected to minimize the risk of distal adding-on?

Explanation

To prevent distal "adding-on" in Lenke 1A curves, the lowest instrumented vertebra (LIV) is typically chosen as the stable vertebra, or the end vertebra if it also happens to be the neutral vertebra. Stopping short of the neutral or stable vertebra significantly increases the risk of adding-on.

Question 84

A 60-year-old woman with breast cancer presents with progressive back pain and lower extremity weakness. MRI shows a metastatic lesion at T8 with high-grade epidural spinal cord compression. The tumor is historically highly radiosensitive. Based on the NOMS framework, what is the most appropriate initial management?

Explanation

According to the NOMS (Neurologic, Oncologic, Mechanical, Systemic) framework, high-grade epidural spinal cord compression requires urgent surgical decompression (separation surgery) before radiation therapy. This applies even to radiosensitive tumors, as the cord must be decompressed to safely and effectively deliver radiation.

Question 85

A 42-year-old man presents with acute bilateral sciatica, saddle anesthesia, and urinary retention (post-void residual of 600 mL) starting 12 hours ago. MRI shows a massive L4-L5 disc herniation compressing the thecal sac. What is the most critical prognostic factor for the return of his bowel and bladder function following emergent decompression?

Explanation

The single most important prognostic factor for neurologic recovery, particularly regarding bowel and bladder function, in cauda equina syndrome is the time elapsed from symptom onset to surgical decompression. Surgery should ideally be performed within 24 to 48 hours.

Question 86

A 65-year-old woman presents with neurogenic claudication and low back pain. Radiographs reveal a grade I degenerative spondylolisthesis at L4-L5 that is mobile on flexion-extension views. MRI shows severe central canal stenosis. According to the SLIP trial, which treatment provides the best long-term clinical outcome?

Explanation

The SLIP trial demonstrated that for patients with lumbar spinal stenosis and degenerative spondylolisthesis, decompression with instrumented fusion provides superior clinical outcomes compared to laminectomy alone. Fusion prevents progressive postoperative instability and recurrent symptoms.

Question 87

A healthy, active 75-year-old man falls and sustains a Type II odontoid fracture with 3 mm of displacement. He is neurologically intact. What is the most appropriate management that provides the highest union rate and lowest morbidity?

Explanation

In active elderly patients, Type II odontoid fractures have a high nonunion rate with conservative care, and halo vest immobilization is associated with high morbidity and mortality. Posterior C1-C2 fusion provides the highest union rate and functional outcome in this demographic.

Question 88

A 55-year-old Asian man presents with progressive cervical myelopathy. Lateral radiographs and MRI reveal continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. The cervical spine maintains normal lordosis, and the K-line is positive. Which of the following surgical interventions is most appropriate?

Explanation

Posterior cervical laminoplasty is ideal for multilevel OPLL when cervical lordosis is preserved and the K-line is positive (the OPLL does not cross the line connecting the midpoints of the spinal canal at C2 and C7). Anterior approaches carry a higher risk of dural tears and complications in OPLL, though they are indicated if the spine is kyphotic.

Question 89

A 62-year-old woman with L4-L5 degenerative spondylolisthesis and neurogenic claudication elects to undergo surgical intervention after failing conservative management. Which of the following pre-operative MRI findings is most predictive of microinstability and would strongly necessitate an arthrodesis in addition to decompression?

Explanation

A facet joint effusion greater than 1.5 mm on T2-weighted axial MRI is highly predictive of microinstability in degenerative spondylolisthesis. Decompression alone in the presence of this finding has a high failure rate, making concomitant arthrodesis the recommended treatment.

Question 90

A 22-year-old man sustains a C4 complete spinal cord injury in a diving accident. In the trauma bay, his blood pressure is 80/50 mm Hg, heart rate is 48 bpm, and his extremities are warm and well-perfused. Which of the following best explains his hemodynamic instability?

Explanation

The patient is experiencing neurogenic shock, characterized by hypotension, bradycardia, and warm extremities. This results from the disruption of descending sympathetic pathways in the cervical cord, leaving vagal parasympathetic tone unopposed.

Question 91

A 68-year-old woman is being evaluated for progressive sagittal imbalance and severe flatback syndrome following a previous L3-S1 fusion. Radiographs reveal a pelvic incidence (PI) of 65 degrees and a current lumbar lordosis (LL) of 20 degrees. To optimize her postoperative clinical outcomes, her revision surgery should aim to restore her lumbar lordosis to approximately what value?

Explanation

For optimal sagittal balance, the lumbar lordosis (LL) should be matched to within 10 degrees of the pelvic incidence (PI). Therefore, a patient with a PI of 65 degrees should have a surgical target LL of approximately 55 to 65 degrees.

Question 92

A 60-year-old man undergoes a C3-C6 posterior laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day one, he develops new, isolated right-sided deltoid and biceps weakness (strength 2/5). His sensory exam and lower extremity motor exams are normal. An urgent MRI shows adequate cord decompression without hematoma. What is the most appropriate next step in management?

Explanation

Isolated C5 palsy is a known complication following cervical decompression, likely due to posterior cord shift and tethering of the C5 nerve root. In the absence of a compressive hematoma or hardware misplacement, most cases recover spontaneously with conservative management and physical therapy.

Question 93

A 45-year-old intravenous drug user presents with 2 weeks of worsening back pain, low-grade fevers, and acute onset of bilateral lower extremity weakness over the last 12 hours (ASIA C). MRI reveals a large ventral epidural abscess spanning L2 to L5. What is the most appropriate management?

Explanation

Spinal epidural abscess presenting with an acute, progressive neurologic deficit is an absolute surgical emergency. Emergent open surgical decompression and debridement, followed by culture-directed IV antibiotics, is required to prevent irreversible neurologic injury.

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

Orthopedic Spine 2026 MCQs: Board Review Questions & Answers (Part 2)

Key Takeaway

Orthopedic Spine 2026 MCQs: Board Review Questions & Answers (Part 2)

Chapter Index