ABOS Spine MCQs Set 3: Degenerative Spine & Trauma Questions

Question 1

What is the most common complication of halo vest immobilization in adults?

Explanation

Although pin loosening generally has not been considered a major problem, it has been cited as the most common complication in two published series of halo vest complications. The other possible complications are all significantly less common. Baum JA, Hanley EN Jr, Pullekines J: Comparison of halo complications in adults and children. Spine 1989;14:251-252. Garfin SR, Botte MJ, Waters RL, Nickel VL: Complications in the use of the halo fixation device. J Bone Joint Surg Am 1986;68:320-325.

Question 2

What is the most common neurologic complication following an anterior cervical diskectomy and fusion?

Explanation

The recurrent laryngeal nerve provides innervation to the vocal cords and was the most common neurologic injury reported in a series of 36,000 patients. The nerve is felt to be more vulnerable during a right-sided approach because of its anatomic course. A recent study has also suggested a role for increased endotracheal cuff pressures in this nerve injury. Flynn TB: Neurologic complications of anterior cervical interbody fusion. Spine 1982;7:536-539.

Question 3

An otherwise healthy 45-year-old woman reports the onset of severe right leg pain. Figure 20a shows an axial MRI scan of the L4-5 level, and Figure 20b shows a sagittal view with the arrow at the L4-5 level. What nerve root is the most likely source of her pain?

Explanation

The scans show a disk herniation in the far lateral region of the disk. In particular, the sagittal view shows the herniation adjacent to the exiting L4 nerve root. Disk herniations in this area that cause symptoms are more likely to compress the nerve exiting at the same level rather than the next most caudal level. McCulloch JA: Microdiscectomy, in Frymoyer JW (ed): The Adult Spine: Principles and Practice. New York, NY, Raven Press, 1991, vol 2, pp 1765-1783.

Question 4

Which of the following forms of nonsurgical management is considered best for acute low back pain without radiculopathy?

Explanation

Temporary bed rest (less than 4 days) with gradual resumption of activities can be efficacious. Epidural steroid injections may be indicated for acute low back pain with radiculopathy. Acupuncture, facet joint injections, or ligamentous (sclerosant) injections are not indicated. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, Appendix A15.

Question 5

A type 2A hangman's fracture, which has the potential to overdistract with traction, has which of the following hallmark findings?

Explanation

Type 2A hangman's fractures are thought to have a flexion mechanism rather than extension and axial loading. This allows them to rotate around the anterior longitudinal ligament into flexion. Anterior translation of greater than 3 mm and angulation distinguish type 2 fractures from type 1 fractures. Although there is an association between C1 ring fractures and C2 fractures, this does not factor into the classification. If a C2-3 facet dislocation exists in combination with a C2 pars fracture, it is considered a type 3 fracture. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 197-217.

Question 6

Figures 21a and 21b show the radiographs of a 22-year-old man who was shot through the abdomen the previous evening. An exploratory laparotomy performed at the time of admission revealed a colon injury. Current examination reveals no neurologic deficits. Management for the spinal injury should include

Explanation

IV broad-spectrum antibiotics should be administered for 7 days. This regimen, when compared to fragment removal or other antibiotic regimens, has been shown to reduce the incidence of spinal infections and reduce the need for metallic fragment removal with perforation of a viscus. Roffi RP, Waters RL, Adkins RH: Gunshot wounds to the spine associated with a perforated viscus. Spine 1989;14:808-811.

Question 7

Stability at the atlanto-occipital joint is provided mainly by

Explanation

The atlanto-occipital joint is inherently unstable and would easily dislocate without the supporting ligaments. The apical ligament attaches to the basion and tip of the dens but does not provide adequate stability to the joint. Werne demonstrated that dividing the tectorial membrane and the alar ligaments resulted in gross joint instability. The anterior longitudinal ligament turns into the anterior atlanto-occipital membrane. This is called a membrane rather than a ligament because it is not strong enough to support these two structures. Werne S: Studies in spontaneous atlas dislocation. Acta Orthopaedica Scandinavica 1977;23(supplement).

Question 8

Which of the following are considered characteristic features of degeneration of a disk?

Explanation

Gradual dessication of the disk begins in the third decade as glycosaminoglycan levels within the nucleus begin to decline. The original water content of 88% decreases to 70% in the sixth decade and beyond. As glycosaminoglycan content decreases, there is a corresponding increase in noncollagen glycoprotein. Happey F, Weissman A, Naylor A: Polysaccharide content of the prolapsed nucleus pulposus of the human intervertebral disc. Nature 1961;192:868. Naylor A, Shentall R: Biomechanical aspects of intervertebral discs in aging and disease, in Jayson M (ed): The Lumbar Spine and Back Pain. New York, NY, Grune and Stratton Inc, 1976, pp 317-326.

Question 9

What spinal nerves in the cauda equina are primarily responsible for innervation of the bladder?

Explanation

The spinal nerves primarily responsible for bladder function are the S2, S3, and S4 nerve roots. With significant compression of the cauda equina by either disk herniation, tumor, or degenerative stenosis, bladder dysfunction may result. Hoppenfeld S: Physical Examination of the Spine and Extremities. Norwalk, CT, Appleton-Century-Crofts, 1976, p 254.

Question 10

Figures 22a and 22b show the radiograph and sagittal MRI scan of the upper cervical spine of a 62-year-old woman who has had a long history of rheumatoid arthritis. Following hospitalization and skeletal traction, her symptoms improve significantly, her neurologic examination returns to normal, and repeat radiographs show a normal occiput and C1-C2 relationship. Treatment should now include

Explanation

Although opinions differ on whether a decompression is indicated in a patient with symptomatic basilar invagination, it is generally agreed that occipitocervical stabilization is indicated. This has been done with and without concomitant arthrodesis. Crockard HA, Grob D: Rheumatoid arthritis upper cervical involvement, in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, p 701.

Question 11

What is the prognosis for ambulation, from best to worst, for patients with an incomplete spinal cord injury?

Explanation

Of the incomplete spinal cord injuries, Brown-Sequard syndrome has the best prognosis for ambulation. Central cord syndrome has a variable recovery. Anterior cord syndrome has the worst prognosis, with motor recovery rare below the level of the injury. Apple DF: Spinal cord injury rehabilitation, in Herkowitz HN, Garfin SR, Balderston RA, Eismont FJ, Bell GR, Wiesel SW (eds): Rothman-Simeone The Spine, ed 4. Philadelphia, PA, WB Saunders, 1999, pp 1130-1131.

Question 12

A skeletally mature 15-year-old girl who was thrown from the car in a rollover accident sustained the injuries shown in Figures 23a through 23d. Examination reveals no neurologic deficit, but the patient has moderate posterior spinal tenderness at the level of the injury. What is the most appropriate treatment?

Explanation

The majority of patients with thoracolumbar burst fractures without neurologic deficit can be effectively treated with a TLSO or a hyperextension body cast. Indications for surgery are neurologic deficit and/or significant deformity (greater than 50% loss of anterior vertebral body height or marked kyphosis). Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 197-217.

Question 13

The MRI scan shown in Figure 24 reveals a right-sided herniated nucleus pulposus at L4-5 in a patient with pain in the right leg. Administration of a caudal epidural steroid injection provides immediate relief. Over the next week he notes generalized weakness of the lower extremities and has one episode of urinary incontinence. What is the next most appropriate step in management?

Explanation

Whenever a patient's condition changes following a test or a procedure, the physician must determine the cause. A steroid flare reaction will not cause incontinence or weakness of the lower extremities. An L4-5 diskectomy may alleviate the problem if the right-sided L4-5 disk herniation is the etiology of the symptoms. However, it is unlikely that a right-sided disk herniation alone will cause a cauda equina syndrome. Possible etiologies include a further extrusion of a disk fragment at L4-5 that now obliterates the spinal canal, a disk herniation at another level, or an epidural abscess following injection of corticosteroids through a caudal approach. In the presence of a possible infection, myelography should not be performed from a lumbar puncture. The fastest and least invasive way to make an appropriate diagnosis is to obtain an MRI of the lumbar spine. In this patient, the MRI revealed an epidural abscess that was compressing the cauda equina. Because of the large dose of steroids that were injected, the patient did not manifest symptoms such as fevers and chills until late in the course. Knight JW, Cordingley JJ, Palazzo MG: Epidural abscess following epidural steroid and local anaesthetic injection. Anaesthesia 1997;52:576-578.

Question 14

At the L4-5 level, what is the location of the S2-5 nerve roots in relationship to the L5 and S1 nerve roots?

Explanation

The nerve roots of S2-5 are positioned dorsally and in the midline relative to the L5 and S1 nerve roots. The L5 nerve root is located lateral to S1 as it prepares to exit under the L5 pedicle. The S1 nerve root is located lateral and ventral to the S2-5 nerve roots. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 3-17.

Question 15

A comparison of dural tears repaired with suture alone and those treated by suture with fibrin glue supplementation will reveal which of the following findings?

Explanation

Animal studies assessing the influence of fibrin glue supplementation have detected a markedly greater inflammatory response at the site of application. An increased incidence of infection and delays in healing were not noted. Cain JE Jr, Rosenthal HG, Broom MJ, Jauch EC, Borek DA, Jacobs RR: Quantification of leakage pressures after durotomy repairs in the canine. Spine 1990;15:969-970.

Question 16

A 19-year-old woman reports lower back pain following a motor vehicle accident. Radiographs obtained immediately after the accident and a bone scan obtained 4 weeks later are shown in Figures 25a through 25c. The patient asks questions regarding the cause, genetics, and natural history of her condition. She should be informed that the condition was

Explanation

The radiographs show L5 spondylolysis without spondylolisthesis (slip). The bone scan is normal, indicating that the pars interarticularis fractures are not acute. The incidence of spondylolysis is approximately 5% in the general population. The lesion generally develops in children age 5 to 6 years, and there is a second peak in the adolescent population. There is a familial predisposition, with reported rates of 27% to 69% in close relatives. A recent long-term follow-up study found that 90% of the spondylolisthesis had occurred before the patient's first visit to the physician. Spondylolisthesis tends to progress during the initial growth spurt and is similar in some respects to idiopathic scoliosis. Progression of a lytic spondylolysis to spondylolisthesis in adulthood has been reported; however, this is exceedingly rare. Lauerman WC, Cain JE: Isthmic spondylolisthesis in the adult. J Am Acad Orthop Surg 1996;4:201-208. Hensinger RN: Spondylolysis and spondylolisthesis in children and adolescents. J Bone Joint Surg Am 1989;71:1098-1107. Seitsalo S, Osterman K, Hyvarinen H, Tallroth K, Schlenzka D, Poussa M: Progression of spondylolisthesis in children and adolescents: A long-term follow-up of 272 patients. Spine 1991;16:417-421.

Question 17

A patient underwent an anterior cervical diskectomy and interbody fusion for a C5-6 herniated nucleus pulposus and left C6 radiculopathy 8 months ago. He now reports new onset of severe neck pain and left C6 radicular pain, with wrist extension weakness. The radiograph and CT scan shown in Figures 26a and 26b reveal pseudarthrosis at C5-6. The next step in management should consist of

Explanation

Brodsky and associates reviewed 34 cases of cervical pseudarthrosis after anterior fusion. Seventeen were treated with revision anterior fusion and 17 with posterior foraminotomy and fusion. Good results were seen in 75% of patients who underwent revision anterior surgery, but better results (94%) were seen with posterior surgery, including foraminotomy and stabilization. Tribus and associates reported treatment of 16 patients with pseudarthrosis using revision anterior debridement of the fibrous tissue and fusion with autograft and plates. There was improvement of the neck in 75% of the patients, nonunion in 19%, continued weakness in 28%, and dysphagia in 5%. Farey and associates reported on 19 patients treated with posterior foraminotomy, stabilization, and fusion with a fusion rate of 100%, resolution of arm pain in 94%, resolution of weakness in 100%, and resolution of neck pain in 75%. It would appear that posterior foraminotomy is more effective for relieving arm pain and neurologic deficits associated with pseudarthrosis. Posterior fusion has the most reliable rate of arthrodesis in this setting. Dysphagia is reported in some patients undergoing more extensive anterior dissections required for applying plates. A neck brace is unlikely to aid in healing of pseudarthrosis in a patient who underwent surgery 8 months ago. A neck brace would be most effective within the first 3 months if a delayed union is identified. Brodsky AE, Khalil MA, Sassard WR, Neuman BP: Repair of symptomatic pseudarthrosis of anterior cervical fusion: Posterior versus anterior repair. Spine 1992;17:1137-1143. Tribus CB, Corteen DP, Zdeblick TA: The efficacy of anterior cervical plating in the management of symptomatic pseudarthrosis of the cervical spine. Spine 1999;24:860-864.

Question 18

A 44-year-old farmer involved in a rollover accident on his tractor sustained an L1 burst fracture with a 20% loss of anterior vertebral body height, 30% canal compromise, and 15 degrees of kyphosis. He remains neurologically intact. The preferred initial course of action should consist of

Explanation

Surgical decompression is unnecessary in a patient with no neurologic deficit and canal compromise of less than 50%. A compression deformity of less than 50% and kyphosis of less than 30 degrees may be successfully treated with a TLSO extension brace. Deformity in this range will reliably heal with minimal risk for late deformity or residual pain. Although some studies suggest 6 weeks of bed rest as treatment, early mobilization and bracing is preferred. Hartman MB, Chrin AM, Rechtine GR: Nonoperative treatment of thoracolumbar fractures. Paraplegia 1995;33:73-76. Chow GH, Nelson BJ, Gebhard JS, Brugman JL, Brown CW, Donaldson DH: Functional outcome of thoracolumbar burst fractures managed with hyperextension casting or bracing and early mobilization. Spine 1996;21:2170-2175.

Question 19

A 40-year-old carpenter has a 3-month history of right arm pain and neck pain that now leaves him unable to work. Examination reveals a positive Spurling test, weakness of the biceps, and a mildly positive Hoffman's sign on the right side. Electromyography and nerve conduction velocity studies show a right C6 deficit. Figures 27a through 27c show MRI scans that reveal two-level spondylotic disease at C5-6 and C6-7, a large herniated nucleus pulposus at C5-6, and a prominent ridge and hard disk at C6-7. Nonsurgical management fails to provide relief, so the patient elects surgical intervention. Which of the following surgical options would give the best long-term results?

Explanation

The patient has a single-level deficit by clinical examination but an adjacent level that may be pathologic. Hilibrand and associates, in a review of 374 patients with myeloradiculopathy treated with single-level or multilevel anterior cervical diskectomy and fusion, showed that 25% of patients had an occurrence of new radiculopathy or myelopathy at an adjacent level within 10 years after surgery. Reoperation rates were highest in those patients where the adjacent nonfused segment was C5-6 or C6-7. Those patients who had multilevel fusions had a lower incidence of adjacent segment disease. The authors recommended incorporating an adjacent level in the initial procedure in patients with myelopathy or radiculopathy when significant disease was noted. Posterior keyhole foraminotomy is an excellent procedure for single-level radiculopathy but is not effective in relieving myelopathy. Anterior cervical diskectomy without fusion has an increased incidence of hypermobility and neck pain on long-term follow-up. In a later review, these authors reported improved fusion rates and better clinical outcomes with the use of strut fusions instead of multilevel interbody grafts. Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH: Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am 1999;81:519-528. 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.

Question 20

A patient with rheumatoid arthritis has an unstable pseudarthrosis after undergoing C1-2 posterior fusion. No neurologic deficits are noted, and repair with posterior transarticular fixation screws and a posterior wiring technique at C1-2 is planned. Which of the following preoperative studies offers the best visualization?

Explanation

Dickman and associates reported a greater than 10% incidence of vertebral artery anomalies at the C1-2 junction that would preclude the use of either unilateral or bilateral transarticular screw placement. They noted that 13 of 105 patients had a high-riding transverse foramen that precluded bilateral screw placement. In another series, 17 of 94 patients had unilateral high-riding transverse foramina and three had bilateral anomalies. Thin-cut CT with sagittal reconstructions offers the best visualization of the anomalous position of the vertebral artery. They noted that single screw placement in combination with posterior C1-2 fusion was an effective means to secure C1-2 stability. MRI gives excellent visualization of soft tissues and spinal cord compression but is not as clear as thin-cut CT for visualization of the vertebral artery foramina. Vertebral artery angiography is an invasive study with an inherent potential for complications. Electromyography does not correlate with vertebral artery anatomy. Paramore CG, Dickman CA, Sonntag VK: The anatomic suitability of the C1-2 complex for transarticular screw fixation. J Neurosurg 1996;85:221-224. Dickman CA, Sonntag VK: Posterior C1-C2 transarticular screw fixation for atlantoaxial arthrodesis. Neurosurgery 1998;43:275-280.

Question 21

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

Explanation

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

Question 22

In the treatment of thoracic disk herniations, what approach is associated with the highest risk of iatrogenic paraplegia?

Explanation

Laminectomy is associated with the highest risk of iatrogenic paraplegia because retraction on the cord is necessary for visualization, but retraction is difficult because of tethering of the intradural dentate ligaments. All of the other approaches allow for access to the disk herniation through an angle that avoids the cord itself, although other limitations may exist. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 87-96.

Question 23

Which of the following factors is the strongest predictor of vertebral fracture in postmenopausal women?

Explanation

If a woman has two or more osteoporotic compression fractures, her risk of another is increased 12 fold. A decrease of two standard deviations in bone mineral density increases the risk four to six fold, a positive family history 2.7 fold, premature menopause 1.6 fold, and smoking 1.2 fold. It should be noted that these studies were carried out in Caucasian and Asian women. Melton LJ III: Epidemiology of spinal osteoporosis. Spine 1997;22:2S-11S.

Question 24

A 23-year-old man sustains a unilateral jumped facet with an isolated cervical root injury in a motor vehicle accident. Acute reduction results in some initial improvement of his motor weakness. Over the next 48 hours, examination reveals ipsilateral loss of pain and temperature sensation in his face, limbs, and trunk, as well as nystagmus, tinnitus, and diplopia. What is the most likely etiology for these changes?

Explanation

The patient is showing signs of vertebral artery stroke. The signs of Wallenberg syndrome include those listed above, as well as contralateral loss of pain and temperature sensation throughout the body, an ipsilateral Horner's syndrome, dysphagia, and ataxia. Vertebral artery injuries are not unusual in significant cervical facet injuries. A lesion in the cervical spinal cord is not associated with these symptoms, and an intracranial hemorrhage from trauma is unlikely to present in this manner. Young PA, Young PH: Basic Clinical Neuroanatomy. Baltimore, MD, Williams and Wilkins, 1997, pp 242-243. Hauop JS, et al: The cause of neurologic deterioration after acute cervical spinal cord injury. Spine 2001;26:340-346.

Question 25

A 60-year-old woman with a history of breast cancer has progressive paraparesis. The MRI scan is shown in Figure 28. What form of management is most likely to restore or maintain ambulation?

Explanation

Surgical decompression and stabilization have been shown to be the most effective means of improving neurologic function. Decompression is most reliably done from the side of the compression, which is anterior in this patient. Harrington KD: Metastatic tumors of the spine: Diagnosis and treatment. J Am Acad Orthop Surg 1993;1:76-86.

Question 26

A 65-year-old man presents with progressive clumsiness in his hands and difficulty walking. Examination reveals hyperreflexia and a positive Hoffman sign. What is the most sensitive physical examination finding for early cervical spondylotic myelopathy?

Explanation

Hoffman's sign is considered one of the most sensitive upper motor neuron signs for early cervical spondylotic myelopathy. It typically indicates cervical spinal cord compression above the C6 level.

Question 27

A 72-year-old woman complains of neurogenic claudication. She fails 6 months of nonoperative management. A decompressive laminectomy is planned. Which of the following anatomic structures is the primary contributor to central canal stenosis in this condition?

Explanation

Hypertrophy of the ligamentum flavum, along with facet arthropathy, is the primary contributor to central canal stenosis in degenerative lumbar stenosis. The ligament buckles into the canal as the disc space collapses.

Question 28

A 35-year-old man falls from a roof and sustains an L1 burst fracture. He is neurologically intact. Which of the following radiographic parameters is the most important determinant for surgical intervention based on the TLICS classification?

Explanation

In the Thoracolumbar Injury Classification and Severity (TLICS) score, PLC disruption is a critical determinant of instability. A neurologically intact patient with an definitively ruptured PLC is generally recommended for surgical stabilization.

Question 29

When evaluating a patient with adult spinal deformity, which of the following spinopelvic parameters is a fixed morphologic feature of the pelvis that does not change with patient position?

Explanation

Pelvic incidence is a fixed anatomic parameter unique to each individual and does not change with postural position. It is defined geometrically as the sum of pelvic tilt and sacral slope.

Question 30

A 60-year-old woman presents with lower back pain and left leg pain. Imaging reveals a grade 1 L4-5 degenerative spondylolisthesis. Which of the following is the most significant structural risk factor for the development of degenerative spondylolisthesis?

Explanation

A more sagittal orientation of the facet joints is a strong predisposing factor for the development of degenerative spondylolisthesis, particularly at L4-L5. Female sex and advancing age are also major risk factors.

Question 31

A 78-year-old man is involved in a low-speed motor vehicle collision. CT scan of the cervical spine reveals a displaced Type II odontoid fracture. Which of the following factors is most strongly associated with nonunion if treated conservatively with a halo vest?

Explanation

Risk factors for nonunion of Type II odontoid fractures include age greater than 50 years, displacement greater than 5 mm, posterior displacement, and delay in treatment. Advanced age is widely considered the strongest single predictor of nonunion.

Question 32

A 16-year-old gymnast complains of chronic lower back pain. Radiographs reveal an L5-S1 isthmic spondylolisthesis. If surgical fusion and reduction are indicated, what is the most common neurologic complication during the reduction of a high-grade slip?

Explanation

The L5 nerve root is most commonly injured due to a stretch injury during the surgical reduction of a high-grade L5-S1 isthmic spondylolisthesis. This occurs because the L5 root is tethered around the sacral ala.

Question 33

A 55-year-old man with a long history of ankylosing spondylitis presents with new-onset neck pain after a minor ground-level fall. Initial plain radiographs are read as normal. 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 after seemingly trivial trauma. If plain films are normal or equivocal, a CT scan or MRI of the spine is mandatory to rule out occult fractures.

Question 34

A 45-year-old man is involved in a high-speed accident. CT scan shows a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation and minimal translation. The C2-C3 disc space is significantly widened. What is the Levine-Edwards classification of this injury?

Explanation

A Levine-Edwards Type IIA Hangman's fracture is characterized by severe angulation with minimal translation and abnormal widening of the C2-C3 disc space. It is caused by flexion-distraction forces and longitudinal traction is contraindicated.

Question 35

A 40-year-old man presents with right arm pain, numbness in his thumb, and weakness in wrist extension. The brachioradialis reflex is diminished. Which cervical nerve root is most likely affected?

Explanation

C6 radiculopathy typically presents with pain and numbness radiating to the thumb, weakness in wrist extension and elbow flexion, and a diminished brachioradialis reflex.

Question 36

A 48-year-old man presents with acute severe right leg pain following heavy lifting. An MRI demonstrates a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

Explanation

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

Question 37

A 65-year-old woman with pre-existing cervical spondylosis falls forward and strikes her chin. She presents with bilateral upper extremity weakness (hands worse than shoulders) and relatively preserved lower extremity strength. What is the most likely diagnosis?

Explanation

Central cord syndrome classically occurs after a hyperextension injury in a patient with a stenotic cervical canal. It presents with disproportionate upper extremity weakness, particularly affecting fine motor function in the hands.

Question 38

In the Lenke classification for adolescent idiopathic scoliosis, a curve is considered 'structural' if it lacks flexibility on side-bending radiographs. What residual Cobb angle on side-bending defines a structural curve?

Explanation

In the Lenke classification system, a minor curve is defined as structural if it does not bend down to less than 25 degrees (i.e., remains 25 degrees or greater) on coronal side-bending radiographs.

Question 39

A 62-year-old man undergoes a C3-C6 posterior cervical laminectomy and fusion. On postoperative day 2, he develops profound weakness in bilateral deltoid and biceps muscles without new sensory changes. What is the most widely accepted pathophysiology of this complication?

Explanation

Postoperative C5 palsy is a well-known complication after cervical decompression. The most accepted theory is the posterior drift of the spinal cord following laminectomy, leading to tethering and stretch injury of the short C5 nerve roots.

Question 40

A 52-year-old diabetic patient presents with severe back pain, fever, and progressive bilateral lower extremity weakness. MRI reveals a continuous ventral epidural fluid collection from L1 to L4. What is the most commonly isolated organism in spontaneous spinal epidural abscesses?

Explanation

Staphylococcus aureus is by far the most common causative organism for spontaneous spinal epidural abscesses and vertebral osteomyelitis, accounting for over 60% of culture-positive cases.

Question 41

A 75-year-old woman with severe osteoporosis presents with an acute, painful T12 compression fracture. She has failed 6 weeks of aggressive conservative management, including bracing and narcotic analgesics. Which of the following is the most appropriate next step?

Explanation

Balloon kyphoplasty or vertebroplasty is indicated for osteoporotic vertebral compression fractures that remain persistently painful and functionally debilitating despite a 4-6 week trial of comprehensive conservative management.

Question 42

A 60-year-old woman with a 20-year history of rheumatoid arthritis requires elective total hip arthroplasty. Flexion-extension cervical radiographs reveal an anterior atlantodens interval (ADI) of 8 mm. She is neurologically intact. What is the most appropriate management regarding her cervical spine prior to hip surgery?

Explanation

An ADI > 3.5 mm indicates atlantoaxial instability. In an RA patient with an ADI of 8 mm awaiting general anesthesia, a preoperative MRI is essential to evaluate the space available for the cord (SAC), as a SAC < 14 mm predicts a high risk of neurologic injury.

Question 43

A 68-year-old man with adult degenerative scoliosis presents with a 45-degree lumbar curve. Surgery is planned. To minimize the risk of proximal junctional kyphosis (PJK), what is an important intraoperative consideration regarding the upper instrumented vertebra (UIV)?

Explanation

To minimize the risk of proximal junctional kyphosis (PJK) in adult spinal deformity, the upper instrumented vertebra (UIV) should be chosen at a stable, sagittally neutral segment. The posterior tension band (interspinous ligaments) must also be carefully preserved.

Question 44

A 45-year-old intravenous drug user presents with mid-back pain and fevers. MRI shows T8-T9 disc space narrowing with endplate destruction and a small epidural phlegmon without cord compression. The patient is neurologically intact. Blood cultures grow MRSA. What is the primary treatment?

Explanation

In a neurologically intact patient with pyogenic spondylodiscitis, no mechanical instability, and a known organism from blood cultures, the mainstay of treatment is a prolonged course of culture-directed intravenous antibiotics.

Question 45

A 25-year-old woman presents to the trauma bay after a high-speed motor vehicle collision where she was wearing only a lap belt. She has a large abdominal ecchymosis. Radiographs reveal a transverse fracture through the pedicles, pars, and vertebral body of L2. What associated injury must be heavily suspected?

Explanation

A Chance fracture (flexion-distraction injury) in the setting of a lap-belt mechanism is highly associated with concurrent intra-abdominal hollow viscus injuries (e.g., small bowel rupture), which occur in up to 50% of these cases.

Question 46

A 70-year-old man presents with severe neck pain and weakness after a fall where he struck his forehead. Examination reveals significant motor weakness in the bilateral upper extremities, particularly the hands, with relatively preserved strength in the lower extremities. Which of the following is the most likely diagnosis?

Explanation

Central cord syndrome typically occurs after a hyperextension injury in a patient with pre-existing cervical spondylosis, causing disproportionately greater upper extremity motor impairment compared to the lower extremities.

Question 47

A 25-year-old man is involved in a motor vehicle collision and sustains an isolated Jefferson (C1 ring) fracture. The 'Rule of Spence' on an open-mouth odontoid radiograph evaluates the combined overhang of the C1 lateral masses on C2. Overhang greater than what measurement suggests a rupture of the transverse atlantal ligament?

Explanation

The Rule of Spence dictates that a combined overhang of the C1 lateral masses on C2 greater than 6.9 mm (or 8.1 mm with radiographic magnification) strongly suggests transverse ligament incompetence.

Question 48

Which of the following spinopelvic parameters is a fixed morphological parameter that is NOT altered by patient positioning or spinal alignment changes?

Explanation

Pelvic incidence (PI) is a fixed anatomical parameter that does not change with positioning. It is the sum of pelvic tilt (PT) and sacral slope (SS), which are both dynamic.

Question 49

A 45-year-old man presents with a far lateral (extra-foraminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed, and what clinical finding would be expected?

Explanation

A far lateral disc herniation at L4-L5 compresses the exiting L4 nerve root, leading to L4 radiculopathy. This typically presents with quadriceps weakness (decreased knee extension) and a diminished patellar reflex.

Question 50

A 35-year-old woman undergoes a posterior cervical laminectomy and fusion for cervical myelopathy. Postoperatively on day 2, she develops isolated weakness in bilateral shoulder abduction and elbow flexion. There are no sensory changes or leg weakness. What is the most likely cause of her new deficit?

Explanation

C5 palsy is a known complication following posterior cervical decompression (laminectomy or laminoplasty). It is thought to occur due to posterior shift of the spinal cord causing tethering of the short C5 nerve root.

Question 51

A 60-year-old man with a 10-year history of ankylosing spondylitis presents to the emergency department after a low-energy fall. He reports new-onset back pain but has intact neurology. Initial 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, frequently occult spinal fractures even after minor trauma. A CT scan of the entire spine is the gold standard to rule out a fracture in this population.

Question 52

A 22-year-old man sustains a seatbelt flexion-distraction (Chance) injury of the thoracolumbar spine in a motor vehicle collision. Which of the following associated injuries is most commonly found with this specific fracture pattern?

Explanation

Chance fractures, which are flexion-distraction injuries commonly caused by lap seatbelts, have a high association (up to 50%) with intra-abdominal injuries, particularly hollow viscus (e.g., bowel) tears.

Question 53

A 45-year-old man is diagnosed with a paracentral disc herniation at L5-S1. He presents with severe leg pain, numbness along the lateral aspect of his foot, and weakness. Which physical examination finding corresponds to this specific level of compression?

Explanation

A paracentral disc herniation at L5-S1 compresses the traversing S1 nerve root. S1 radiculopathy classically presents with weakness in ankle plantarflexion (gastrocnemius/soleus) and a diminished Achilles reflex.

Question 54

Which of the following factors is most strongly associated with a high rate of nonunion in Type II odontoid fractures treated with rigid cervical collar immobilization?

Explanation

Risk factors for nonunion in Type II odontoid fractures include age >50 years, initial displacement >5 mm, angulation >10 degrees, and delayed treatment.

Question 55

A 65-year-old patient undergoes a T10 to pelvis posterior spinal fusion for adult degenerative scoliosis. One year later, they complain of severe back pain and leaning forward. Radiographs show failure of the proximal construct with kyphosis above the upper instrumented vertebra. What is this complication called?

Explanation

Proximal junctional kyphosis (PJK) is a common complication after long spinal fusions, characterized by an abnormal kyphotic angle developing between the upper instrumented vertebra (UIV) and the vertebrae immediately proximal to it.

Question 56

According to the ASIA Impairment Scale, a patient who has sensory preservation but no motor function preserved below the neurological level of injury is classified as:

Explanation

ASIA B designates a sensory incomplete spinal cord injury where sensory function is preserved (including S4-S5), but motor function is completely absent below the neurological level.

Question 57

A 30-year-old male is brought to the emergency department after a motor vehicle accident. He is comatose with a Glasgow Coma Scale score of 6. A CT scan demonstrates a right-sided C5-C6 unilateral facet dislocation. What is the most appropriate next step in management regarding his cervical spine injury?

Explanation

In an obtunded or unexaminable patient with a cervical facet dislocation, an MRI must be obtained prior to reduction. This is to rule out a compressive disc herniation that could cause severe neurologic injury upon reduction.

Question 58

A 65-year-old male presents with bilateral leg pain that worsens with walking and is relieved by leaning forward over a shopping cart. Examination reveals normal pedal pulses. Which of the following findings is most likely to be present on electrodiagnostic testing (EMG/NCS)?

Explanation

The clinical presentation is classic for neurogenic claudication caused by lumbar spinal stenosis. EMG/NCS in patients with symptomatic lumbar stenosis typically demonstrates multi-root, bilateral radicular changes or multilevel paraspinal denervation.

Question 59

A 16-year-old male presents with increasing thoracic kyphosis and mid-back pain. Radiographs reveal anterior wedging of multiple thoracic vertebrae. According to the Sorensen criteria, what specific radiographic finding is required to formally diagnose classic Scheuermann's kyphosis?

Explanation

The classic Sorensen criteria for Scheuermann's disease require the presence of at least 3 consecutive thoracic vertebrae demonstrating greater than 5 degrees of anterior wedging each.

Question 60

A 45-year-old construction worker falls 15 feet, sustaining an L1 burst fracture. He is neurologically intact on presentation. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following radiographic parameters is the strongest indication for operative stabilization over nonoperative brace management?

Explanation

Disruption of the posterior ligamentous complex (PLC) indicates a grossly unstable fracture pattern resulting in a TLICS score of 4 or higher. While severe canal compromise or severe kyphosis are factors, definitive PLC disruption is a clear indication for surgery.

Question 61

A 72-year-old woman complains of deteriorating handwriting, clumsiness in her hands, and unsteadiness when walking in the dark. On examination, rapidly flicking the distal phalanx of her middle finger into flexion causes a reflex flexion of her thumb and index finger. What is the name of this clinical sign?

Explanation

Hoffmann's sign is elicited by flicking the distal phalanx of the middle finger, producing reflex flexion of the thumb and index finger. It is an upper motor neuron sign highly suggestive of cervical spondylotic myelopathy in this clinical context.

Question 62

An 80-year-old male trips and falls, striking his chin. CT of the cervical spine shows a fracture through the base of the odontoid process extending down into the cancellous body of C2. According to the Anderson and D'Alonzo classification, what type of fracture is this, and what is the typical initial treatment for a neurologically intact elderly patient?

Explanation

A fracture extending into the cancellous body of C2 is a Type III odontoid fracture. In both young and elderly neurologically intact patients, these fractures typically heal well with nonoperative rigid cervical collar immobilization.

Question 63

In the evaluation of Adolescent Idiopathic Scoliosis (AIS), the Lenke classification system utilizes the flexibility of curves on side-bending radiographs to determine fusion levels. A minor thoracic curve is considered "structural" if the Cobb angle on the side-bending radiograph fails to reduce below what specific threshold?

Explanation

In the Lenke classification for AIS, a minor curve is considered structural if it remains 25 degrees or greater on lateral side-bending radiographs, or if there is local kyphosis >20 degrees.

Question 64

A 65-year-old man with pre-existing cervical stenosis is involved in a rear-end collision, sustaining a hyperextension injury. He presents with profound weakness in his hands and arms (1/5 strength), but retains functional 4/5 strength in his legs and is able to walk. What is the most likely diagnosis?

Explanation

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

Question 65

A 42-year-old male presents with severe right anterior thigh pain and weakness in knee extension. An MRI of the lumbar spine reveals a far-lateral (extra-foraminal) disc herniation at the L3-L4 level. Which nerve root is most likely compressed by this specific herniation?

Explanation

Far-lateral (extra-foraminal) disc herniations compress the exiting nerve root at the level of the disc space. Therefore, an L3-L4 far-lateral herniation will compress the exiting L3 nerve root.

Question 66

A 45-year-old male with long-standing Ankylosing Spondylitis presents with a severe, rigid chin-on-chest cervicothoracic kyphotic deformity. He is unable to see straight ahead. Which of the following surgical procedures is the standard, safest choice at the cervicothoracic junction to correct this deformity?

Explanation

A C7 opening wedge extension osteotomy is the classic procedure to correct severe cervicothoracic kyphosis in ankylosing spondylitis. C7 is chosen due to the relatively wide spinal canal and the mobility of the C8 nerve root, minimizing neurologic risk.

Question 67

A 35-year-old female sustains a pelvic ring injury and a sacral fracture following a fall from height. CT imaging shows the fracture line passes medial to the sacral foramina, involving the central sacral canal. According to the Denis classification of sacral fractures, what zone is involved, and what is the approximate risk of associated neurologic injury?

Explanation

Denis Zone 3 sacral fractures involve the central sacral canal (medial to the neural foramina). Because they directly compromise the cauda equina, they carry the highest rate of neurologic injury, frequently exceeding 50%.

Question 68

A 14-year-old competitive gymnast presents with chronic low back pain. Radiographs demonstrate a grade II L5-S1 spondylolisthesis. Which of the following pathoanatomical features is characteristic of this condition (isthmic spondylolisthesis) as opposed to degenerative spondylolisthesis?

Explanation

Isthmic spondylolisthesis is characterized by a structural defect or elongation (stress fracture) of the pars interarticularis, most commonly at L5-S1. Degenerative spondylolisthesis features an intact pars and most frequently occurs at L4-L5.

Question 69

A 55-year-old male undergoes a complex 9-hour posterior spinal fusion for adult spinal deformity. Upon waking, he complains of severe bilateral vision loss. A diagnosis of postoperative visual loss (POVL) is made. What is the most common etiology of POVL following prolonged posterior spine surgery?

Explanation

Ischemic optic neuropathy (ION) is the most common cause of postoperative visual loss (POVL) following prolonged spine surgery in the prone position. Major risk factors include prolonged operative time, significant blood loss, and massive fluid resuscitation.

Question 70

According to the Canadian C-Spine Rules, which of the following is considered a "high-risk" factor that strictly mandates obtaining cervical spine radiography in an alert, stable trauma patient?

Explanation

The Canadian C-Spine Rules identify age 65 or older, a dangerous mechanism (e.g., fall >3 feet, axial load), or the presence of extremity paresthesias as major high-risk factors that unconditionally mandate cervical imaging.

Question 71

The off-label use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in anterior cervical discectomy and fusion (ACDF) has been associated with a significantly increased risk of which of the following life-threatening postoperative complications?

Explanation

The use of rhBMP-2 in the anterior cervical spine is strongly linked to profound prevertebral soft tissue swelling. This rapid, massive edema can lead to catastrophic postoperative airway compromise and severe dysphagia.

Question 72

A 12-year-old male with spastic quadriplegic cerebral palsy (Gross Motor Function Classification System level V) presents with a severe 90-degree sweeping thoracolumbar scoliosis and significant pelvic obliquity. When planning surgical correction and posterior fusion, what is the most appropriate distal extent of the instrumented fusion?

Explanation

In completely non-ambulatory patients with neuromuscular scoliosis and marked pelvic obliquity, fusion must typically extend to the sacrum and pelvis. This is necessary to fully correct the obliquity, level the pelvis, and provide a stable, balanced sitting posture.

Question 73

A 78-year-old man sustains a Type II odontoid fracture with 5 mm of posterior displacement after a fall. He is neurologically intact. Non-operative management with a halo vest is being considered. Compared to rigid cervical collar immobilization, halo vest placement in this specific patient population is associated with a significantly higher risk of:

Explanation

In elderly patients (typically >65 years) with Type II odontoid fractures, halo vest immobilization is associated with significantly higher morbidity and mortality, primarily from respiratory complications, compared to rigid cervical collars or surgery.

Question 74

A 65-year-old man with neurogenic claudication secondary to L4-L5 spinal stenosis fails conservative management and undergoes a lumbar decompression. During the procedure, which of the following anatomic structures must be partially resected to adequately decompress the traversing nerve root in the lateral recess?

Explanation

The lateral recess is bordered laterally by the pedicle, posteriorly by the superior articular facet, and anteriorly by the vertebral body and disc. Resection of the medial aspect of the superior articular process is required to decompress the traversing nerve root.

Question 75

A 13-year-old girl with adolescent idiopathic scoliosis (AIS) has a right thoracic curve of 55 degrees. She is Risser 0. Pulmonary function testing demonstrates a forced vital capacity (FVC) of 55% of predicted. What is the most appropriate surgical approach?

Explanation

Posterior spinal fusion is the standard of care for large thoracic curves in AIS. Anterior approaches are generally contraindicated in patients with diminished pulmonary function (FVC < 60% to 70% predicted) due to the risk of postoperative pulmonary decline.

Question 76

A 35-year-old man falls from a height and sustains an L1 burst fracture. He is neurologically intact. Upright radiographs demonstrate 20 degrees of kyphosis and 40% loss of anterior vertebral body height. CT shows 30% canal compromise. The posterior ligamentous complex is intact on MRI. What is the most appropriate management?

Explanation

In neurologically intact patients with thoracolumbar burst fractures and an intact posterior ligamentous complex, non-operative management with a TLSO brace or cast provides equivalent long-term clinical outcomes compared to surgery.

Question 77

A 55-year-old man presents with progressive bilateral hand clumsiness and a broad-based gait. Physical examination reveals positive Hoffman signs bilaterally. MRI shows multi-level cervical stenosis from C3-C6 with focal cord signal changes. Which of the following is the most reliable clinical indicator of a poor prognosis for neurologic recovery after surgical decompression?

Explanation

A prolonged duration of symptoms (typically >12 to 18 months) prior to surgery is one of the strongest negative predictors for neurologic recovery in cervical spondylotic myelopathy. T1 hypointensity (not T2 hyperintensity alone) also portends a poor prognosis.

Question 78

A 25-year-old woman is involved in a motor vehicle accident. She is awake and alert. Neurologic exam reveals 0/5 strength in the bilateral triceps and hand intrinsics, with absent sensation below C7. Radiographs show a bilateral C6-C7 facet dislocation. MRI cannot be obtained within the next 4 hours. What is the most appropriate next step?

Explanation

In an awake, cooperative, and examinable patient with a cervical facet dislocation and a severe neurologic deficit, immediate closed reduction with cranial traction is indicated to relieve spinal cord compression as rapidly as possible, without waiting for an MRI.

Question 79

A 68-year-old woman presents with severe low back pain and an inability to stand upright. Standing full-length radiographs reveal a sagittal vertical axis (SVA) of +12 cm, a pelvic incidence (PI) of 60 degrees, and a lumbar lordosis (LL) of 20 degrees. What are the primary radiographic targets for surgical correction of her sagittal balance?

Explanation

Proper sagittal balance correction in adult spinal deformity targets a Sagittal Vertical Axis (SVA) of less than 5 cm, a Pelvic Incidence to Lumbar Lordosis (PI-LL) mismatch of less than 10 degrees, and a Pelvic Tilt (PT) of less than 20 degrees.

Question 80

A 30-year-old man presents after a motorcycle crash with a Denis zone 3 sacral fracture. He has loss of bowel and bladder control and perineal numbness. What is the likelihood of neurologic injury with this specific fracture zone compared to zones 1 and 2?

Explanation

Denis zone 3 sacral fractures involve the central sacral canal and carry the highest rate of neurologic injury (up to 60%), frequently presenting with bowel, bladder, and sexual dysfunction due to sacral nerve root involvement.

Question 81

A 48-year-old man presents with severe right-sided anterior thigh pain, weakness in knee extension, and a diminished right patellar reflex. MRI demonstrates a right-sided far lateral (extraforaminal) disc herniation at L4-L5. Which nerve root is most likely compressed?

Explanation

A far lateral (extraforaminal) disc herniation impinges the exiting nerve root at that level. At the L4-L5 level, a far lateral herniation will compress the exiting L4 nerve root, leading to quadriceps weakness and a diminished patellar reflex.

Question 82

A 16-year-old boy presents with aching back pain and a rounded thoracic spine. Standing lateral radiographs reveal a thoracic kyphosis of 80 degrees and anterior wedging of 3 consecutive vertebrae of 10 degrees each. What other radiographic finding is a classic hallmark of this condition?

Explanation

Scheuermann's kyphosis is characterized by rigid thoracic kyphosis >45 degrees, anterior wedging of at least 5 degrees in 3 or more consecutive vertebrae, irregular endplates, and Schmorl's nodes (disc herniations into the vertebral endplate).

Question 83

A 65-year-old man with cervical spondylosis sustains a hyperextension injury. He presents with profound weakness in his hands and arms, but is able to ambulate with mild lower extremity weakness. He has preserved perianal sensation. Which of the following best describes his expected prognosis for neurologic recovery?

Explanation

This is a classic presentation of central cord syndrome. Recovery typically occurs in a predictable pattern: lower extremities recover first, followed by bowel/bladder, then proximal upper extremities, with fine motor hand intrinsic function recovering last and often incompletely.

Question 84

A 60-year-old woman is 5 years status post an L4-S1 posterior spinal fusion. She presents with new-onset neurogenic claudication. Imaging reveals severe L3-L4 spinal stenosis and degenerative spondylolisthesis. Which biomechanical factor most significantly contributes to adjacent segment disease following lumbar fusion?

Explanation

Adjacent segment disease is driven by altered biomechanics following a rigid spinal fusion. The construct transfers stress, significantly increasing intradiscal pressure and segmental hypermobility at the unfused segments immediately adjacent to the fusion.

Question 85

A 12-year-old boy wearing a lap belt is involved in a high-speed motor vehicle collision. Radiographs reveal a flexion-distraction injury (Chance fracture) at L2. Which of the following associated injuries must be most highly suspected and urgently evaluated?

Explanation

Chance fractures (flexion-distraction injuries) are frequently associated with seatbelt injuries. There is a high incidence (up to 40-50%) of concurrent intra-abdominal hollow viscus injuries, making urgent general surgery evaluation critical.

Question 86

A 15-year-old male athlete presents with chronic, severe axial low back pain exacerbated by extension. Imaging confirms bilateral L5 pars interarticularis defects without spondylolisthesis. MRI shows normal, hydrated discs. After 6 months of rest and core strengthening, pain prevents sports participation. What is the most appropriate surgical management?

Explanation

Direct pars repair (e.g., Buck's, Scott's, or screw-hook constructs) is indicated for young patients with symptomatic pars defects without significant slip who fail conservative management and have healthy adjacent discs, as it preserves lumbar motion.

Question 87

A 55-year-old man with a 20-year history of ankylosing spondylitis presents with new severe neck pain after a low-speed rear-end motor vehicle collision. Radiographs appear unchanged from previous films, showing a continuous "bamboo spine". His neurologic exam is completely intact. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis have a highly rigid spine that is extremely susceptible to unstable, catastrophic fractures from minor trauma. Advanced imaging (CT or MRI) is mandatory for any new pain after trauma to rule out occult fractures that standard radiographs easily miss.

Question 88

A 65-year-old man with pre-existing cervical spondylosis sustains a hyperextension injury. He has severe upper extremity weakness and mild lower extremity weakness. What is the most appropriate initial management for this incomplete spinal cord injury if there is no acute instability or worsening compression?

Explanation

Central cord syndrome commonly occurs after hyperextension injuries in stenotic cervical spines. Initial management includes maintaining mean arterial pressure (MAP) >85 mmHg for spinal cord perfusion; routine early surgery or steroids are not strictly indicated without progressive deterioration.

Question 89

When correcting adult spinal deformity, which of the following pelvic parameters represents a morphologic constant that dictates the required amount of lumbar lordosis (LL) for a balanced spine?

Explanation

Pelvic incidence (PI) is a fixed morphologic parameter of the pelvis that does not change with posture. A well-balanced spine typically requires the lumbar lordosis (LL) to be within 10 degrees of the PI (PI - LL < 10 degrees).

Question 90

A 32-year-old involved in a motor vehicle accident presents with neck pain and right C6 radiculopathy. Radiographs reveal an isolated right unilateral C5-C6 facet dislocation. What is the most appropriate next step prior to closed reduction?

Explanation

In an awake, alert patient with a unilateral facet dislocation and a radicular deficit, an MRI should be obtained prior to closed reduction to rule out a herniated disc. If a large disc herniation is present, anterior decompression should be performed prior to reduction to prevent cord injury.

Question 91

An 82-year-old man sustains a Type II odontoid fracture after a fall from standing. He is neurologically intact but has severe neck pain. He has multiple comorbidities including severe COPD. What is the most appropriate management?

Explanation

In elderly patients (especially >80 years) with significant comorbidities, halo vest immobilization has an unacceptably high morbidity and mortality rate. Rigid cervical collar immobilization is often preferred for Type II odontoid fractures in this specific demographic despite lower union rates, prioritizing survival.

Question 92

A 25-year-old man wearing a lap seatbelt sustains a flexion-distraction injury to the L2 vertebra. Which of the following associated injuries is most highly correlated with this fracture pattern?

Explanation

Chance fractures (flexion-distraction injuries) commonly occur with lap seatbelts when the fulcrum of flexion is anterior to the spine. They have a high association (up to 50%) with intra-abdominal hollow viscus injuries, making prompt general surgery evaluation crucial.

Question 93

A 55-year-old man undergoes a posterior cervical laminectomy and fusion from C3-C7 for cervical spondylotic myelopathy. On postoperative day 2, he develops profound isolated weakness in right shoulder abduction and external rotation. What is the most likely etiology?

Explanation

Postoperative C5 palsy frequently occurs after posterior cervical decompression due to posterior drift of the spinal cord and subsequent tethering or stretching of the short, horizontally oriented C5 nerve roots. It usually recovers spontaneously over several months with conservative care.

Question 94

A 65-year-old woman presents with neurogenic claudication and L4-L5 degenerative spondylolisthesis. She fails conservative management. According to the SPORT trial, what is the expected outcome of surgical decompression and fusion compared to nonoperative care?

Explanation

The Spine Patient Outcomes Research Trial (SPORT) demonstrated that patients treated surgically for degenerative spondylolisthesis maintained significantly greater improvement in pain and physical function at 4 years compared to those treated nonoperatively.

Question 95

Which of the following radiographic criteria is strictly required for the classical diagnosis of Scheuermann's kyphosis?

Explanation

Sorensen's criteria for classic Scheuermann's disease stipulate a thoracic kyphosis > 45 degrees accompanied by anterior wedging of > 5 degrees in at least three consecutive vertebrae.

Question 96

In the Thoracolumbar Injury Classification and Severity (TLICS) score, which neurologic status receives the highest numerical value?

Explanation

Under the TLICS system, incomplete spinal cord injuries or cauda equina syndrome receive 3 points, which is higher than a complete spinal cord injury (2 points). This higher score reflects the potential benefit and urgency of surgical decompression for incomplete injuries.

Question 97

During an L4-L5 laminectomy for severe spinal stenosis, a 1 cm incidental durotomy occurs dorsally. What is the most appropriate intraoperative management?

Explanation

Incidental durotomies recognized intraoperatively should be primarily repaired with fine nonabsorbable sutures (e.g., prolene or nylon) in a watertight fashion. Avoidance of high-suction drains is also recommended to prevent CSF fistula formation.

Question 98

A 14-year-old gymnast presents with persistent low back pain. Radiographs demonstrate a Grade II isthmic spondylolisthesis at L5-S1. Conservative treatment fails. What is the most common nerve root affected in this condition that causes radicular symptoms?

Explanation

In isthmic spondylolisthesis at L5-S1, the fibrocartilaginous tissue at the pars interarticularis defect (Gill nodule) hypertrophies. This mass commonly compresses the exiting L5 nerve root within the neuroforamen.

Question 99

A 60-year-old man presents with progressive hand clumsiness and broad-based gait. MRI of the cervical spine shows severe stenosis at C4-C5 with T2 hyperintensity within the spinal cord. What does this MRI finding indicate regarding his prognosis?

Explanation

T2 hyperintensity in the spinal cord on MRI represents edema or myelomalacia. In the setting of cervical spondylotic myelopathy, it indicates chronic cord injury and is highly associated with a poorer prognosis and limited functional recovery following decompression.

Question 100

A 55-year-old woman with a 20-year history of rheumatoid arthritis presents with neck pain and occipital headaches. Flexion-extension radiographs reveal an anterior atlantodental interval (ADI) of 11 mm. What is the most appropriate definitive management?

Explanation

An anterior atlantodental interval (ADI) > 9-10 mm in a patient with rheumatoid arthritis indicates a high risk for neurologic compromise and disruption of the alar and transverse ligaments. Posterior C1-C2 fusion is indicated to stabilize the atlantoaxial joint.

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

AAOS Spine Surgery MCQs (Set 3): Degenerative Spine, Trauma & Deformity | ABOS & OITE Review

Key Takeaway

AAOS Spine Surgery MCQs (Set 3): Degenerative Spine, Trauma & Deformity | ABOS & OITE Review

Chapter Index