ABOS Spine MCQs (Set 2): Lumbar Stenosis & Trauma Qs

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

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

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

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

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

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 68-year-old man presents with bilateral leg pain that worsens with walking and is relieved by leaning on a shopping cart. Examination reveals normal distal pulses and absent ankle reflexes. Which of the following findings best differentiates neurogenic claudication from vascular claudication?

Explanation

Neurogenic claudication typically radiates proximal to distal and is relieved by lumbar flexion, such as sitting or leaning forward. Vascular claudication radiates distal to proximal, is relieved by standing still, and is exacerbated by uphill walking due to increased metabolic demand.

Question 27

A 35-year-old man falls from a roof. CT scan shows a T12 burst fracture with 40% loss of vertebral body height and splaying of the pedicles. MRI shows an intact posterior ligamentous complex (PLC). Neurological exam is completely normal. What is his Thoracolumbar Injury Classification and Severity (TLICS) score and recommended treatment?

Explanation

The TLICS score is calculated as: Burst fracture morphology (2 points), intact PLC (0 points), and intact neurologic status (0 points), totaling 2 points. A score of 3 or less is typically treated non-operatively with bracing and early mobilization.

Question 28

A 70-year-old female presents with severe neurogenic claudication and L4-L5 degenerative spondylolisthesis (Grade 1). She has failed non-operative management. According to the SPORT trial, what is the most appropriate surgical intervention?

Explanation

The SPORT trial demonstrated that for degenerative spondylolisthesis with spinal stenosis, decompressive laminectomy with instrumented fusion provides better long-term outcomes than laminectomy alone. Laminectomy alone in the setting of instability risks further slip progression.

Question 29

A 22-year-old female sustains a seatbelt injury in a high-speed motor vehicle collision. Radiographs and CT show a fracture line extending horizontally through the spinous process, pedicles, and vertebral body of L2. What associated injury must be actively ruled out?

Explanation

Chance fractures (flexion-distraction injuries) sustained via seatbelts are highly associated with intra-abdominal hollow viscus injuries, occurring in up to 40-50% of cases. Prompt general surgery consultation and abdominal imaging are essential.

Question 30

A patient with severe central canal stenosis at L3-L4 and L4-L5 presents with new-onset urinary incontinence and perianal numbness. Cauda equina syndrome is suspected. Which urodynamic finding is most characteristic of this condition?

Explanation

Cauda equina syndrome causes lower motor neuron dysfunction, leading to a flaccid, areflexic bladder. This manifests clinically as detrusor areflexia with a large post-void residual and overflow incontinence.

Question 31

A 45-year-old male falls from a ladder, sustaining an L1 burst fracture. He has weakness in bilateral knee extension (3/5) and ankle dorsiflexion (2/5). MRI confirms severe canal compromise by a retropulsed bone fragment. What is the most appropriate surgical approach?

Explanation

In the setting of an incomplete neurological deficit with anterior canal compromise from a burst fracture fragment, anterior decompression (corpectomy) and stabilization is highly effective. Posterior laminectomy alone is contraindicated as it destabilizes the spine without adequately addressing the anterior compressive pathology.

Question 32

A 40-year-old construction worker with Grade II isthmic spondylolisthesis at L5-S1 complains of severe radicular pain. If surgical decompression is planned, which nerve root is most commonly compressed in this specific pathology?

Explanation

In isthmic spondylolisthesis at L5-S1, the L5 nerve root is most commonly compressed as it exits the neural foramen. It is typically impinged by the hypertrophic fibrocartilaginous tissue at the pars defect.

Question 33

According to the Denis three-column theory of the spine, which of the following anatomical structures is a primary component of the middle column?

Explanation

The Denis middle column consists of the posterior half of the vertebral body, the posterior half of the annulus fibrosus, and the posterior longitudinal ligament. Disruption of this middle column is the defining feature of a burst fracture.

Question 34

A 65-year-old female underwent an L4-S1 posterior instrumented fusion 5 years ago. She now presents with new-onset L3 radiculopathy and neurogenic claudication. Imaging confirms adjacent segment degeneration. Which intra-operative factor most significantly increases the risk of developing adjacent segment disease?

Explanation

Failure to restore or maintain physiological lumbar lordosis (sagittal malalignment) significantly increases biomechanical stress on adjacent un-fused levels. This iatrogenic flatback deformity is a primary driver for adjacent segment disease.

Question 35

A patient sustains an unstable T12-L1 fracture-dislocation. He exhibits symmetric, flaccid paralysis of the lower extremities, absent bulbocavernosus reflex, and early fecal incontinence. Examination reveals a mixture of upper and lower motor neuron signs. This presentation is most consistent with:

Explanation

Conus medullaris syndrome results from injury at the T12-L1 level and classically presents with a mix of upper and lower motor neuron signs, early sphincter dysfunction, and symmetric deficits. Cauda equina syndrome is purely lower motor neuron and usually asymmetric.

Question 36

On a T2-weighted axial MRI of the lumbar spine, a patient with severe central stenosis exhibits "redundant nerve roots." What does this finding indicate?

Explanation

The "redundant nerve root" sign on MRI represents elongated, tortuous nerve roots proximal to a high-grade stenotic block. It is a marker of chronic, severe lumbar stenosis and correlates with poorer post-operative neurological recovery.

Question 37

A 62-year-old male with a history of long-standing ankylosing spondylitis presents with back pain after a minor ground-level fall. Initial plain radiographs of the thoracic and lumbar spine are interpreted as negative. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis have rigid, brittle spines and can sustain highly unstable transdiscal or transvertebral fractures from low-energy trauma. If radiographs are negative, advanced imaging (CT or MRI) of the entire spine is mandatory to rule out occult fractures.

Question 38

During an L3-L5 decompressive laminectomy for severe lumbar stenosis, an incidental durotomy occurs. The tear is repaired primarily with 4-0 non-absorbable suture. Which of the following is the most appropriate post-operative drain management?

Explanation

In the setting of an incidental durotomy, drains (especially under suction) should generally be avoided to prevent pulling cerebrospinal fluid through the repair. A vacuum drain risks creating a persistent CSF fistula and hindering dural healing.

Question 39

A 45-year-old male treated conservatively for a T12 burst fracture one year ago presents with worsening back pain and progressive kyphosis (now 35 degrees). What is the primary biomechanical rationale for performing an anterior and posterior fusion rather than a posterior-only fusion in this setting?

Explanation

In delayed post-traumatic kyphosis, the anterior column is often deficient and rigidly deformed. An anterior release and strut grafting provides necessary load-sharing and addresses the anterior column defect, which a posterior-only construct would likely fail to maintain.

Question 40

A 72-year-old man with mild neurogenic claudication and L4-L5 stenosis desires minimally invasive surgery. An interspinous process spacer is being considered. Which of the following is a strict contraindication to this device?

Explanation

Interspinous process spacers rely on an intact posterior bony arch and stable segments to maintain distraction. Gross instability, such as a Grade II or greater spondylolisthesis, is a strict contraindication as it can lead to device migration or fracture.

Question 41

A trauma patient with a known T11 burst fracture develops sudden, severe bradycardia and hypotension during transport. His extremities are warm and well-perfused. Which of the following is the most likely cause?

Explanation

Sudden hypotension and bradycardia with warm, flushed extremities is the hallmark of neurogenic shock. It is caused by the loss of sympathetic tone following a spinal cord injury above T6, leading to unopposed vagal tone.

Question 42

Achondroplasia is frequently associated with early-onset symptomatic lumbar stenosis. Which anatomical feature of the lumbar spine is classically observed in these patients?

Explanation

In achondroplasia, patients classically exhibit a progressive decrease in the interpedicular distance from L1 to L5, contrary to the normal spine where it widens. This leads to severe congenital central canal stenosis.

Question 43

An 80-year-old female presents with severe localized back pain after coughing. X-rays reveal a new L1 anterior wedge compression fracture. After 6 weeks of conservative management (bracing, analgesics), her pain remains VAS 8/10. What is the most appropriate next step?

Explanation

Vertebroplasty or balloon kyphoplasty is indicated for osteoporotic vertebral compression fractures that fail conservative management (usually after 4-6 weeks) and are characterized by severe, localized pain. It provides rapid pain relief through cement stabilization.

Question 44

A 68-year-old male presents with bilateral lower extremity pain and fatigue when walking. Which of the following historical findings is most specific for differentiating neurogenic claudication from vascular claudication?

Explanation

Neurogenic claudication is classically relieved by lumbar flexion, such as when pushing a shopping cart, because it increases the cross-sectional area of the spinal canal. Vascular claudication is typically relieved simply by resting or standing still.

Question 45

A 65-year-old female presents with severe neurogenic claudication and an L4-L5 grade I degenerative spondylolisthesis. According to the Spine Patient Outcomes Research Trial (SPORT), which of the following best describes the outcome of surgical versus nonoperative treatment at 4-year follow-up?

Explanation

The SPORT trial demonstrated that patients treated surgically for degenerative spondylolisthesis maintained significantly greater improvements in pain and function at 4 years compared to those treated nonoperatively.

Question 46

A 35-year-old male falls from a height and sustains an L1 burst fracture. His neurologic examination is normal. An MRI confirms that the posterior ligamentous complex (PLC) is completely intact. What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and what is the generally recommended treatment?

Explanation

The TLICS score is calculated as follows: Burst morphology (2 points), intact PLC (0 points), and normal neurologic status (0 points), giving a total score of 2. A score of 3 or less is typically treated nonoperatively.

Question 47

A 22-year-old female is involved in a high-speed motor vehicle collision while wearing a lap belt. She sustains a severe flexion-distraction injury (Chance fracture) at L2. What is the most commonly associated concomitant injury in this specific scenario?

Explanation

Chance fractures, particularly those caused by lap belts in motor vehicle collisions, are highly associated with intra-abdominal injuries, most notably hollow viscus injuries (e.g., bowel perforation).

Question 48

A 70-year-old male with long-standing ankylosing spondylitis presents with back pain after a ground-level fall. CT scan shows a displaced transverse fracture through the T10-T11 disc space extending into the posterior elements. Which of the following is the most appropriate surgical strategy?

Explanation

Fractures in the ankylosed spine are highly unstable shear injuries that act like long lever arms. They require long-segment posterior instrumentation (typically at least three levels above and below) to achieve adequate stability and prevent failure.

Question 49

A 60-year-old male with central lumbar spinal stenosis is considering an epidural steroid injection (ESI). Which of the following best describes the expected efficacy of ESIs for neurogenic claudication based on recent randomized controlled trials?

Explanation

Recent high-quality RCTs have shown that epidural steroid injections may provide short-term symptomatic relief but offer no significant long-term benefit over local anesthetic injections alone for central lumbar stenosis.

Question 50

A 40-year-old male presents with a T12 burst fracture and profound paraparesis (ASIA B). CT reveals 60% canal compromise by a large retropulsed bone fragment. What is the most appropriate definitive management?

Explanation

In the presence of an incomplete spinal cord injury with significant anterior canal compromise and instability, surgical decompression and stabilization is the standard of care to maximize neurological recovery.

Question 51

In the evaluation of a patient with an L5-S1 isthmic spondylolisthesis, which of the following spinopelvic parameters is a fixed morphologic feature of the pelvis that does not change with patient positioning?

Explanation

Pelvic incidence is a fixed anatomical parameter that defines the morphology of the pelvis and dictates the required lumbar lordosis. It does not change with position, unlike pelvic tilt and sacral slope.

Question 52

During a routine L4-L5 lumbar laminectomy for stenosis, a 3-mm incidental durotomy occurs. A primary water-tight repair is achieved intraoperatively. Which of the following postoperative protocols is most supported by recent literature?

Explanation

Recent studies demonstrate that early mobilization following a successful primary watertight repair of an incidental durotomy does not increase complication rates and avoids the morbidity of prolonged bed rest.

Question 53

A 65-year-old female presents with new-onset neurogenic claudication 5 years after an L4-L5 posterolateral fusion. Imaging shows severe L3-L4 central stenosis. Which of the following is considered the strongest modifiable risk factor for the development of adjacent segment disease requiring surgery?

Explanation

Postoperative sagittal imbalance, specifically a hypolordotic fusion (flatback), significantly increases biomechanical stress on the adjacent segments, making it a major risk factor for adjacent segment disease.

Question 54

A 70-year-old male with calf pain after walking two blocks is evaluated. To differentiate neurogenic from vascular claudication, he undergoes a stationary bicycle test. Which finding is most consistent with neurogenic claudication?

Explanation

During the stationary bicycle test, leaning forward (flexion) opens the spinal canal and relieves symptoms of neurogenic claudication. Patients with vascular claudication will experience pain regardless of spinal posture due to muscle ischemia.

Question 55

A 55-year-old male with a history of lumbar stenosis presents to the emergency department with acute urinary retention, saddle anesthesia, and bilateral lower extremity weakness. MRI confirms a massive disc extrusion at L4-L5. Surgical decompression is classically recommended within what maximum timeframe to maximize the chance of bladder function recovery?

Explanation

Decompression within 48 hours for cauda equina syndrome is classically associated with significantly improved rates of neurological and urological recovery compared to delayed surgery.

Question 56

Which of the following biomechanical characteristics most accurately explains why the thoracolumbar junction (T11-L2) is highly susceptible to traumatic fractures?

Explanation

The thoracolumbar junction represents a vulnerable biomechanical transition zone between the rigid, rib-supported kyphotic thoracic spine and the highly mobile, lordotic lumbar spine.

Question 57

The McCormack Load Sharing Classification is used to determine the need for anterior column support in thoracolumbar burst fractures. Which of the following is NOT a criterion assessed in this classification?

Explanation

The Load Sharing Classification specifically evaluates comminution, fracture fragment displacement, and the amount of kyphosis correction needed. Neurological status is not part of this strictly morphologic/biomechanical scoring system.

Question 58

In an adult patient with degenerative lumbar scoliosis and concurrent spinal stenosis, which of the following radiographic parameters is most highly predictive of curve progression?

Explanation

Risk factors for the progression of degenerative lumbar scoliosis include a Cobb angle >30 degrees, apical rotation >Grade II, an intercrest line passing through L5, and lateral listhesis greater than 6 mm.

Question 59

Following a successful multi-level lumbar decompression for central spinal stenosis without instability, which symptom typically demonstrates the LEAST amount of improvement postoperatively?

Explanation

Mechanical low back pain is notoriously unpredictable and typically shows the least improvement compared to lower extremity symptoms (such as neurogenic claudication) following a pure lumbar decompression without fusion.

Question 60

A 68-year-old female presents with severe neurogenic claudication and an L4-L5 grade I degenerative spondylolisthesis. She has failed 6 months of comprehensive physical therapy and epidural steroid injections. Based on the Spine Patient Outcomes Research Trial (SPORT), what is the most appropriate surgical treatment?

Explanation

The SPORT trial demonstrated that for degenerative spondylolisthesis with concomitant spinal stenosis, decompressive laminectomy combined with fusion provides superior long-term functional outcomes compared to nonoperative care or decompression alone.

Question 61

A 35-year-old male falls from 10 feet, sustaining an isolated L1 burst fracture. He is neurologically intact. CT imaging shows 30% canal compromise, and MRI confirms an intact posterior ligamentous complex. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the most appropriate management?

Explanation

The TLICS score for this injury is 2 (Morphology=2 for burst, Neurology=0, PLC=0). A score of less than 4 implies that non-operative management, such as a TLSO brace and early mobilization, is indicated.

Question 62

Which of the following historical or physical examination findings best differentiates neurogenic claudication from vascular claudication?

Explanation

Walking downhill promotes lumbar extension, which decreases the cross-sectional area of the spinal canal and exacerbates neurogenic claudication. Vascular claudication is worsened by exertion regardless of spinal posture and is relieved by standing still.

Question 63

A 22-year-old male is involved in a high-speed motor vehicle collision wearing a lap-belt only. Imaging reveals a flexion-distraction (Chance) fracture at L2. Which associated injury has the highest likelihood of being present and must be urgently ruled out?

Explanation

Chance fractures caused by lap-belt restraints have a high association (up to 50%) with concurrent intra-abdominal injuries, particularly hollow viscus (bowel) rupture, due to acute hyperflexion over the belt.

Question 64

During a wide bilateral lumbar laminectomy for central spinal stenosis, preserving spinal stability is critical. To minimize the risk of iatrogenic pars interarticularis fractures and subsequent instability, what minimum width of the pars must be preserved bilaterally?

Explanation

Biomechanical studies have demonstrated that at least 5 mm of the pars interarticularis must be preserved during decompression to minimize the risk of iatrogenic pars fracture and secondary instability.

Question 65

A 62-year-old male with long-standing, rigid ankylosing spondylitis presents with new-onset mechanical back pain after a ground-level fall. Plain radiographs of the thoracolumbar spine are unrevealing, and neurologic exam is intact. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are highly susceptible to unstable 'chalk-stick' fractures even from minor trauma. If plain films are negative, advanced imaging (CT or MRI) of the entire spine is mandatory to rule out occult fractures.

Question 66

According to randomized controlled trials (e.g., Wood et al.) evaluating the treatment of stable thoracolumbar burst fractures without neurologic deficit, how do the outcomes of TLSO bracing compare to no bracing?

Explanation

Level I evidence from Wood et al. demonstrated that for stable thoracolumbar burst fractures, conservative management with early mobilization without a brace provides equivalent clinical and radiographic outcomes compared to TLSO bracing.

Question 67

A 48-year-old male taking chronic systemic corticosteroids for severe asthma presents with progressive lower extremity weakness. MRI of the lumbar spine reveals marked compression of the thecal sac by excessive, homogenous T1-hyperintense tissue in the posterior epidural space. What is the most appropriate initial management?

Explanation

The patient has spinal epidural lipomatosis, a condition strongly associated with chronic exogenous steroid use. Initial management should focus on nonoperative measures, primarily steroid weaning and weight loss.

Question 68

In degenerative lumbar spinal stenosis, compression of the traversing nerve root within the lateral recess is most commonly caused by hypertrophy of which of the following osseous structures?

Explanation

The traversing nerve root in the lateral recess is most frequently compressed by hypertrophy of the superior articular process (SAP) and the overlying thickened ligamentum flavum.

Question 69

During an L4-L5 laminectomy for severe stenosis, a 1 cm incidental durotomy occurs. It is primarily repaired with a 4-0 nonabsorbable suture, and a Valsalva maneuver confirms a watertight seal. According to current evidence, what is the best postoperative protocol?

Explanation

Recent spine literature confirms that early mobilization following a primarily repaired, watertight incidental durotomy does not increase the risk of CSF leak complications compared to traditional strict bed rest protocols.

Question 70

The Load Sharing Classification (McCormack) of spine fractures is primarily utilized to predict the failure of which surgical intervention?

Explanation

The Load Sharing Classification assesses vertebral body comminution, fragment apposition, and kyphosis to determine if posterior short-segment fixation alone will fail, indicating a need for anterior column structural reconstruction.

Question 71

A 35-year-old male sustains a T12 burst fracture after a fall. He is neurologically intact. MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) scale, his score is calculated as 2 (Burst = 2, Neurologic status = 0, PLC = 0). What is the most appropriate management?

Explanation

Based on the TLICS system, a score of 3 or less is typically treated non-operatively. This patient's score of 2 indicates that non-operative management with a brace is the most appropriate course of action.

Question 72

A 65-year-old man presents with bilateral leg pain when walking. He notes that bicycling causes no pain, and walking downhill exacerbates his symptoms more than walking uphill. Which of the following physical exam findings is most likely to be present?

Explanation

The clinical presentation is classic for neurogenic claudication, which improves with lumbar flexion (bicycling) and worsens with extension (downhill walking). Unlike vascular claudication, these patients typically have normal vascular exams, including an ABI greater than 1.0.

Question 73

A 22-year-old female is involved in a high-speed motor vehicle collision while wearing a lap belt. She complains of severe mid-back pain. CT scan reveals a transverse fracture extending through the pedicles, transverse processes, and vertebral body of L1. Which of the following associated injuries is most commonly seen in this patient?

Explanation

Flexion-distraction injuries (Chance fractures) are highly associated with intra-abdominal pathology due to lap belt compression. Hollow viscus (bowel) injuries occur in up to 40-50% of these cases.

Question 74

A 70-year-old female presents with severe neurogenic claudication. Imaging demonstrates L4-L5 degenerative spondylolisthesis with severe central canal stenosis. Dynamic flexion-extension radiographs reveal 4 mm of translation upon flexion. What is the most appropriate surgical treatment?

Explanation

Decompressive laminectomy with instrumented posterolateral fusion is the standard of care for symptomatic lumbar stenosis with degenerative spondylolisthesis and dynamic instability. Decompression alone carries a significantly higher rate of progressive slip and need for reoperation.

Question 75

In the evaluation of a thoracolumbar fracture, identifying posterior ligamentous complex (PLC) injury is critical for surgical decision making. Which of the following MRI sequences and findings is most sensitive for indicating a disrupted PLC?

Explanation

Fat-suppressed T2-weighted or STIR MRI sequences are highly sensitive for detecting edema. Hyperintensity in the interspinous region strongly correlates with disruption of the posterior ligamentous complex (PLC).

Question 76

A 55-year-old woman presents with L4-5 spinal stenosis and radicular leg pain. Her MRI demonstrates bilateral facet joint effusions greater than 1.5 mm. What does this specific MRI finding suggest regarding her condition?

Explanation

The 'facet fluid sign' on MRI is highly correlated with dynamic lumbar instability, such as degenerative spondylolisthesis. It suggests that a decompressive procedure should likely be accompanied by a fusion to prevent postoperative slip progression.

Question 77

A 40-year-old man falls from a scaffold, sustaining an L1 burst fracture. He has incomplete paraplegia (Frankel C), and a CT scan shows 80% canal compromise by a large retropulsed bone fragment. Which surgical approach is most favored to directly decompress the neural elements in this scenario?

Explanation

For severe canal compromise caused by an anterior retropulsed bone fragment with an incomplete neurological deficit, an anterior approach (corpectomy) allows for direct removal of the compressive pathology and provides structural anterior column support.

Question 78

A 68-year-old man who underwent an L4-S1 posterior instrumented fusion 5 years ago now presents with new-onset neurogenic claudication. Radiographs show intact hardware but a new grade 1 spondylolisthesis at L3-L4. What is the primary biomechanical cause of this new pathology?

Explanation

Adjacent segment disease (ASD) occurs due to increased mechanical stress and hypermobility at the spinal segments immediately adjacent to a solid fusion. This leads to accelerated degeneration, instability, and stenosis at the adjacent level.

Question 79

According to the principles of thoracolumbar trauma management, which of the following is considered an absolute indication for surgical decompression and stabilization of a thoracolumbar burst fracture?

Explanation

A progressive neurological deficit is an absolute indication for urgent surgical decompression and stabilization to maximize the chance of neurologic recovery. Radiographic parameters alone often allow for non-operative management if the patient is intact.

Question 80

When comparing degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) in the adult population, which of the following characteristics accurately differentiates DS from IS?

Explanation

Degenerative spondylolisthesis most commonly occurs at the L4-L5 level in older individuals and features an intact neural arch. In contrast, isthmic spondylolisthesis usually involves a pars defect and is most common at L5-S1.

Question 81

A 30-year-old woman sustains a T12-L1 fracture-dislocation. She presents with flaccid paralysis of the lower extremities, saddle anesthesia, and severe urinary retention. Her bulbocavernosus reflex is absent. This clinical picture is most consistent with an injury to which anatomical structure?

Explanation

The conus medullaris typically terminates at L1. Injuries at the T12-L1 junction can cause severe lower motor neuron signs indicative of conus medullaris and cauda equina involvement, characterized by saddle anesthesia and an areflexic bladder.

Question 82

During a routine L4-L5 decompressive laminectomy for severe spinal stenosis, a 1 cm incidental durotomy occurs ventrally. What is the most appropriate initial intraoperative management of this complication?

Explanation

Incidental durotomies should be repaired primarily with a watertight suture if accessible, often supplemented with a fascial or synthetic patch. Drains should never be placed on high suction near a dural tear, as this promotes cerebrospinal fluid fistulas.

Question 83

A 55-year-old man with a long history of Ankylosing Spondylitis falls from a standing height. He complains of severe back pain but has no neurologic deficits. Plain radiographs show a 'bamboo spine' but no obvious fracture. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable, occult spinal fractures even from minor trauma. Advanced imaging (CT or MRI) of the entire spine is mandatory to rule out a fracture when they present with new back pain.

Question 84

The Spine Patient Outcomes Research Trial (SPORT) evaluated outcomes for surgery versus non-operative care for lumbar spinal stenosis. What did the long-term results conclude regarding decompressive laminectomy for stenosis without spondylolisthesis?

Explanation

The SPORT trial demonstrated that patients treated surgically with decompressive laminectomy for symptomatic lumbar spinal stenosis had significantly greater and sustained improvements in pain and function compared to those treated non-operatively.

Question 85

A 25-year-old male sustains an L2 burst fracture with 60% canal compromise and a complete cauda equina syndrome. You elect to perform a posterior-only approach for decompression and stabilization. What technique is most commonly used to decompress the anterior canal from a posterior approach?

Explanation

In a posterior-only approach for a burst fracture, the anterior canal can be decompressed indirectly via ligamentotaxis or directly via a transpedicular approach. This involves using a tamp down the pedicle to push the retropulsed bone fragment back into the vertebral body.

Question 86

A 65-year-old man presents with bilateral leg pain and cramping that worsens with walking and standing, but is relieved when he leans forward on a shopping cart. Pedal pulses are 2+ bilaterally. Which of the following is the most likely primary pathoanatomic cause of his symptoms?

Explanation

This patient presents with classic neurogenic claudication secondary to lumbar spinal stenosis. The most common pathoanatomy is a combination of ligamentum flavum hypertrophy, facet joint hypertrophy, and intervertebral disc bulging.

Question 87

A 24-year-old man falls from a height of 15 feet and sustains a T12 fracture. CT scan shows a burst fracture with 40% loss of anterior vertebral body height, 15 degrees of kyphosis, and 20% canal compromise. He is neurologically intact. According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is his total score and the recommended treatment?

Explanation

A neurologically intact (0 points) burst fracture (mechanism: 2 points) with an intact posterior ligamentous complex (0 points) gives a TLICS score of 2. A score of 3 or less is an indication for nonoperative treatment, typically with a rigid orthosis.

Question 88

According to the Spine Patient Outcomes Research Trial (SPORT) for degenerative lumbar spondylolisthesis with spinal stenosis, how do the outcomes of surgical decompression and fusion compare to nonoperative management at 4-year follow-up?

Explanation

The SPORT study demonstrated that patients treated surgically for degenerative spondylolisthesis with spinal stenosis maintained significantly greater improvement in pain and function at 4 years compared to those treated nonoperatively. Surgical treatment remains the preferred approach for symptomatic cases failing conservative measures.

Question 89

A 19-year-old woman is a restrained passenger in a high-speed motor vehicle collision. She sustains a severe flexion-distraction injury of L2. Which of the following associated injuries must be evaluated with a high index of suspicion?

Explanation

Flexion-distraction (Chance-type) fractures occur frequently in seatbelt-restrained passengers. They have a high association (up to 40%) with intra-abdominal injuries, particularly hollow viscus injuries like bowel perforations.

Question 90

Which of the following is the strongest indication for adding a concomitant instrumented fusion to a lumbar laminectomy for spinal stenosis?

Explanation

Performing a decompression without fusion in the setting of a mobile degenerative spondylolisthesis significantly increases the risk of progressive postoperative instability. Therefore, concomitant fusion is indicated to stabilize the segment and prevent poor clinical outcomes.

Question 91

A 35-year-old man presents with a T11 fracture after a motor vehicle accident. Examination reveals isolated complete loss of motor function and sensation below the umbilicus, with absent rectal tone. The posterior ligamentous complex is disrupted. What is the most appropriate surgical approach?

Explanation

In a highly unstable thoracolumbar fracture with posterior ligamentous complex disruption and complete neurologic deficit (TLICS > 4), posterior long-segment instrumentation and fusion is generally indicated to restore stability and alignment. Laminectomy alone is contraindicated as it further destabilizes the spine.

Question 92

A 72-year-old woman with known severe lumbar spinal stenosis presents to the emergency department. Which of the following clinical findings most strongly suggests the development of cauda equina syndrome requiring emergent surgical decompression?

Explanation

Urinary retention with overflow incontinence, saddle anesthesia, and decreased anal sphincter tone are hallmark signs of cauda equina syndrome. This represents a surgical emergency requiring immediate decompression to prevent permanent neurologic deficit.

Question 93

A 40-year-old man with ankylosing spondylitis sustains a low-energy fall and complains of severe back pain. Plain radiographs are inconclusive. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable extension-distraction fractures even with minor trauma. If plain radiographs are negative but clinical suspicion remains high, advanced imaging (CT or MRI) of the entire spine is required to rule out an occult fracture.

Question 94

In the evaluation of a patient with suspected lumbar spinal stenosis, which diagnostic imaging modality is considered the gold standard for assessing the degree of central canal, lateral recess, and foraminal narrowing?

Explanation

MRI without contrast is the gold standard imaging modality for diagnosing and quantifying lumbar spinal stenosis. It provides excellent soft tissue resolution to evaluate the intervertebral discs, thecal sac, and individual neural elements.

Question 95

A 28-year-old woman is involved in a severe motor vehicle collision. Radiographs demonstrate a fracture through the pedicles, transverse processes, and posterior vertebral body of L1. The mechanism of injury is predominantly:

Explanation

A fracture line extending horizontally through the posterior elements (pedicles, transverse processes) and into the vertebral body is characteristic of a Chance fracture. This pattern is caused by a flexion-distraction mechanism.

Question 96

When comparing neurogenic claudication to vascular claudication, which of the following characteristics is most specific to neurogenic claudication?

Explanation

Neurogenic claudication is characteristically relieved by lumbar flexion (sitting or leaning forward), which increases the cross-sectional area of the spinal canal and foramina. In contrast, vascular claudication is relieved simply by resting, regardless of spinal posture.

Question 97

A 50-year-old man presents with an L2 burst fracture after a fall. He is neurologically intact. Radiographs show 20 degrees of focal kyphosis and 30% loss of anterior body height. According to current evidence, what is the expected long-term clinical outcome of conservative management with an orthosis compared to surgical stabilization?

Explanation

Multiple randomized controlled trials have shown no significant difference in long-term functional outcomes, pain, or return to work between operative and nonoperative management for neurologically intact thoracolumbar burst fractures. Conservative management is considered a safe and effective approach for these injuries.

Question 98

A 60-year-old patient undergoes an L3-L5 laminectomy for severe central stenosis. During the decompression, an incidental durotomy occurs. What is the most appropriate initial intraoperative management of this complication?

Explanation

An incidental durotomy recognized intraoperatively should be primarily repaired using a fine non-absorbable suture to prevent cerebrospinal fluid leak. While sealants and tight fascial closures are useful adjuncts, primary repair remains the definitive treatment.

Question 99

Which of the following anatomic structures forms the anterior border of the lumbar intervertebral foramen, and may contribute directly to foraminal stenosis when pathological?

Explanation

The anterior border of the lumbar intervertebral foramen is formed by the posterior aspect of the vertebral body and the intervertebral disc. Consequently, a disc herniation or loss of disc height directly narrows the foraminal space anteriorly.

Question 100

A 45-year-old man presents with severe back pain and right leg radiculopathy. MRI reveals a massive L4-L5 right-sided far lateral (extraforaminal) disc herniation. Which nerve root is most likely compressed by this specific lesion?

Explanation

In the lumbar spine, an extraforaminal (far lateral) disc herniation compresses the exiting nerve root at that specific level. Therefore, an L4-L5 far lateral disc herniation will directly impinge upon the exiting L4 nerve root.

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

AAOS Spine Surgery MCQs (Set 2): Lumbar Stenosis & Thoracolumbar Fractures | Board Review

Key Takeaway

AAOS Spine Surgery MCQs (Set 2): Lumbar Stenosis & Thoracolumbar Fractures | Board Review

Chapter Index