ABOS Spine Surgery MCQs (Set 1): Trauma & Degenerative

Question 1

Which is the best initial study for the diagnostic evaluation of diskogenic low back pain?

Explanation

Radiography is the best initial study for the evaluation of diskogenic low back pain. The normal degenerative process can be evaluated. Vacuum phenomenon may be found within the disk space. Other possible sources for back pain should also be evaluated. The other tests may be beneficial but represent later imaging options.

Question 2

A patient who is an observant Jehovah's Witness requires major surgery for scoliosis that will likely result in significant blood loss. Which of the following might the patient consider allowing the surgical team to use?

Explanation

Jehovah's Witnesses will not accept the transfusion of blood or blood products such as packed red or white cells, platelets, or plasma. However, many Jehovah's Witnesses will accept the use of a cell saver in a "closed circuit." Jimenez R, Lewis VO (eds): Culturally Competent Care Guidebook. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007.

Question 3

Which of the following is a contraindication to laminoplasty in a patient with cervical spondylotic myelopathy?

Explanation

Laminoplasty or any posterior decompressive procedure is contraindicated in patients with cervical spondylotic myelopathy and cervical kyphosis. The residual kyphotic posture of the cervical spine results in persistent spinal cord compression. The other choices are not contraindications for laminoplasty. Concomitant cervical radiculopathy can be addressed at the time of laminoplasty with a keyhole foraminotomy. Emery SE: Cervical spondylotic myelopathy: Diagnosis and treatment. J Am Acad Orthop Surg 2001;9:376-388.

Question 4

A 44-year-old man reports persistent left leg pain following a L5-S1 hemilaminotomy and partial diskectomy. Examination shows a grade 4 weakness of the left extensor hallucis longus and a positive left straight leg raise. A radiograph is shown in Figure 1a, and sagittal and axial MRI scans are shown in Figures 1b and 1c. Nonsurgical management consisting of medication, physical therapy, and injections has failed to provide relief. Surgical management should consist of

Explanation

The patient has a grade I isthmic spondylolisthesis at L5-S1. He has an L5 radiculopathy with foraminal stenosis. Any further treatment needs to include an arthrodesis and foraminal decompression. Isolated interbody fusion is contraindicated in patients with spondylolisthesis, as is total disk arthroplasty. Therefore, the best procedure is a posterior fusion with instrumentation and bone graft along with a foraminal decompression. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 311-317.

Question 5

Bisphosphonates are indicated in the treatment of osteoporosis in patients who have a DEXA T-score of

Explanation

Bisphosphonates are indicated in the treatment of osteoporosis. They have been shown to reduce the incidence of vertebral and extremity fractures in patients with a T-score of less than -1.

Question 6

A 45-year-old man reports that he awoke 2 weeks ago with severe pain in his right arm. Examination reveals weakness in the biceps, brachialis, and wrist extensors. There is decreased sensation in the thumb and index finger and a diminished brachioradialis reflex. Assuming this patient has a posterolateral herniated nucleus pulposus, what level is involved?

Explanation

This is a classic C6 nerve injury, and it is most likely the result of a herniated nucleus pulposus at C5-6. The C5 nerve root controls the elbow flexors, shoulder abductors, and external rotators. The C7 nerve root controls the elbow extensors, wrist pronators, and the triceps reflex. Standaert CJ: The patient history and physical examination: Cervical, thoracic and lumbar, in Herkowitz HN, Garfin SR, Eismont FJ, et al (eds): Rothman-Simeone The Spine, ed 5. Philadelphia, PA, Saunders Elsevier, 2006, vol 1, pp 171-186.

Question 7

A 42-year-old woman underwent an instrumented posterior spinal fusion at L3-S1 with transforaminal lumbar interbody fusion. She had an excellent clinical result with complete resolution of leg pain. Three months later she now reports increasing back pain and weakness in her legs. Examination reveals weakness in the quadriceps and tibialis anterior. Radiographs show no interval changes in the position of the hardware. MRI scans are shown in Figures 2a through 2c. What is the next most appropriate step in management?

Explanation

The MRI scans reveal a postoperative infection. Observation and antibiotics are not appropriate choices. There is a large fluid collection and this requires decompression because the patient has neurologic changes. There is considerable debate regarding the removal of hardware. Many contend that biofilm on the implants can harbor the infection. However, these complications usually can be treated with serial irrigations, debridements, and IV antibiotics. The incidence of infection has been widely studied with varying rates in fusions with instrumentation. Rates appear to be increased with instrumentation, yet these infections usually can be managed without hardware removal. Glassman SD, Dimar JR, Puno RM, et al: Salvage of instrumental lumbar fusions complicated by surgical wound infection. Spine 1996;21:2163-2169.

Question 8

What is the primary reason for including the ilium in the distal fixation of long instrumentation constructs in adult scoliosis?

Explanation

Studies have shown that when compared with fixation to the sacrum alone, the success rate of fusion across the lumbosacral junction increases when both the sacrum and ilium are included in the posterolateral construct. Curve correction, coronal balance, and pelvic balance are all attended to within the thoracolumbar spine and are not directly related to the pelvic fixation. Fretting and corrosion are a byproduct of metal-to-metal connections. Islam NC, Wood KB, Transfeldt EE, et al: Extension of fusions to the pelvis in idiopathic scoliosis. Spine 2001;26:166-173.

Question 9

A 60-year-old man is evaluated in the ICU after a rollover motor vehicle accident 3 days ago. He has multiple upper and lower extremity trauma and was found unresponsive at the accident scene. Surgery is planned for the extremity trauma once the patient is medically stable. He remains intubated and the cervical spine is immobilized in a semi-rigid collar. Examination reveals mild erythema in the posterior occipital cervical region. Initial AP and lateral radiographs of the cervical spine have not revealed any obvious fracture. What is the most appropriate treatment option at this time?

Explanation

Ackland and associates demonstrated that the failure to achieve early spinal clearance in an unconscious blunt trauma patient predisposed the patient to increased morbidity secondary to the prolonged used of cervical immobilization. They demonstrated that the four significant predictors of collar-related ulcers were ICU admission, mechanical ventilation, the necessity for cervical MRI, and the time to cervical spine clearance and collar removal. The risk of pressure-related ulceration increased by 66% for every 1-day increase in Philadelphia collar time and this highlights the need for definitive C-spine clearance. Ackland HM, Cooper DJ, Malham GM, et al: Factors predicting cervical collar-related decubitus ulceration in major trauma patients. Spine 2007;32:423-428.

Question 10

A 46-year-old woman who was involved in a motor vehicle accident reports a 4-month history of right-sided lower back pain and pain radiating into the right thigh. The patient underwent an extensive 3-month course of physical therapy and now is dependent on narcotic medication for pain control. Epidural injection therapy has failed to improve her symptoms. Examination is significant for weakness of hip flexion in the seated position and for decreased sensation to light touch in the medial anterior thigh region. Straight leg raise is negative, but the femoral stretch test reproduces anterior thigh pain. A CT myelogram image, at L3-L4, is shown in Figure 3. What is the most appropriate management at this time?

Explanation

The CT scan reveals a right-sided lateral disk protrusion at L3-4 that has been symptomatic for more than 4 months despite appropriate nonsurgical management. Relative surgical indications include persistent radiculopathy despite an adequate trial of nonsurgical management, recurrent episodes of sciatica, persistent motor deficit with tension signs and pain, and pseudoclaudication caused by underlying stenosis. Whereas studies have shown improvement in patients with sciatica from a lumbar disk herniation treated either nonsurgically or surgically, those undergoing surgical treatment had an overall greater improvement of symptoms. Weinstein JN, Lurie JD, Tosteson TD, et al: Surgical vs nonoperative treatment for lumbar disk herniation: The Spine Patient Outcomes Research Trial (SPORT) observational cohort. JAMA 2006;296:2451-2459.

Question 11

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

Explanation

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

Question 12

Osteoporotic vertebral compression fractures are associated with

Explanation

Osteoporotic vertebral compression fractures are associated with neurologic complications in less than 1% of patients. After the initial fracture however, patients have a 20% risk of further fractures. The mortality rate of patients with vertebral fractures exceeds that of patients with hip fractures when they are followed beyond 6 months. Gass M, Dawson-Hughs B: Preventing osteoporosis-related fractures: An overview. Am J Med 2006;119:S3-S11. Lindsay R, Silverman SL, Cooper C, et al: Risk of new vertebral fracture in the year following a fracture. JAMA 2001;285:320-323.

Question 13

When compared to smokers who do not quit, an improvement in the rate of lumbar fusion is seen in patients who cease smoking for at least how many months postoperatively?

Explanation

The effects of cigarette smoking and smoking cessation on spinal fusion have been studied extensively. Although permanent smoking cessation is ideal, significant improvements in fusion rates are seen in patients who avoid smoking for greater than 6 months postoperatively.

Question 14

A 19-year-old woman reports persistent neck pain for 2 years. Pain is relieved with aspirin. A bone scan shows intense uptake in the superior, posterior portion of the C3 vertebral body. A sagittal CT reconstruction is shown in Figure 5. Treatment should consist of

Explanation

The CT scan shows an osteoblastic nidus pathognomic for an osteoid osteoma. Surgical treatment should include an en bloc excision of the lesion. Surgical treatment is not mandatory because the lesion often becomes asymptomatic over time. This lesion is not amenable to radiofrequency ablation due to its proximity to the spinal cord. A complete corpectomy is not necessary to adequately resect the lesion, as only the nidus needs to be removed. Radiation therapy and antibiotics are not appropriate treatments for an osteoid osteoma. Posterior C2-C3 fusion will not address the pathology. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 351-366.

Question 15

A 56-year-old man with a history of chronic lower back pain from lumbar spondylosis reports a 2-day history of acute incapacitating back pain. He denies any history of acute trauma, although he reports the pain starting after a coughing spell. He also reports difficulty urinating and some fecal incontinence. Examination reveals generalized lower extremity weakness, saddle paresthesia, hyporeflexia in the lower extremities, and loss of rectal tone. What is the most appropriate management at this time?

Explanation

Cauda equina syndrome is a medical emergency that must be quickly diagnosed and treated to avoid long-term complications. Cauda equina syndrome typically presents with low back pain, unilateral or usually bilateral sciatica, saddle sensory disturbances, bladder and bowel dysfunction, and variable lower extremity motor and sensory loss. Although a number of pathologies can cause cauda equina syndrome, in a patient with a history of chronic back pain, disk pathology is the most common cause of acute onset cauda equina syndrome. Whereas radiographs may be useful in a traumatic onset of symptoms, MRI is the most appropriate study. Cauda equina syndrome should be evaluated on an emergent basis and admission for work-up is appropriate. Ahn UM, Ahn NU, Buchowski JM, et al: Cauda equina syndrome secondary to lumbar disc herniation: A meta-analysis of surgical outcomes. Spine 2000;25:1515-1522.

Question 16

A 55-year-old woman with a long history of low back and left lower extremity pain has failed to respond to exhaustive nonsurgical management. MRI scans show bulging and degeneration at L3-4 and L4-5 as well as a normal disk at L2-3 and L5-S1. She undergoes provocative lumbar diskography at L3-4, L4-5, and L5-S1. Post-diskography axial CT images of L3-4 and L4-5 are shown in Figures 6a and 6b, respectively. The injections at L3-4 and L4-5 produce no pain. The injection at L5-S1 produces 10/10 concordant back pain with radiation to the lower extremity. What is the most appropriate recommendation at this time?

Explanation

The results of this patient's lumbar diskography are equivocal at best. The two disks most likely to be her pain generators, based on their MRI appearance, produced 10/10 pain, however it was nonconcordant and did not reproduce any of her typical left-sided radicular symptoms. The only disk that produced concordant back pain was the normal disk at the L5-S1 level and it reproduced radicular symptoms on the side opposite of her typical pain. Based on these findings, it would be difficult to select a level or levels to include in a lumbar fusion. As such, continued nonsurgical management is the safest treatment option at the current time. Brox and associates reported on a randomized clinical trial comparing lumbar fusion to cognitive intervention and exercise and found similar results in both groups, with significantly less risk in the latter. Brox JI, Sorensen R, Friis A, et al: Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine 2003;28:1913-1921.

Question 17

A 36-year-old woman is brought to the emergency department intubated and sedated following a motor vehicle accident. She is moving her upper and lower extremities spontaneously. She cannot follow commands. CT scans are shown in Figures 7a through 7c. The initial survey does not reveal any other injuries. Initial management of the cervical injury should consist of immediate

Explanation

The patient has a bilateral facet dislocation of C6-C7 with preservation of at least some neurologic function. Urgent reduction is necessary. However, because she is sedated and unable to follow commands, an MRI scan is necessary before any closed or open posterior reduction to look for an associated disk herniation. If a disk herniation is present, it must be removed prior to any reduction maneuver to prevent iatrogenic neurologic injury. It is very unlikely that this injury can be reduced with an open anterior procedure alone. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 189-199.

Question 18

A 51-year-old woman with no preoperative neurologic deficit is undergoing elective anterior cervical diskectomy and fusion (ACDF) with plating and fusion for a C5-6 disk herniation with right-sided neck pain. Thirty minutes into the surgery the neurophysiologic monitoring shows a rapid drop and then loss of amplitude in the right cortical somatosensory-evoked potential waveform. All other waveforms remained normal and unchanged, including right-sided cervical (subcortical) and peripheral (Erb's point), and those from the left-sided upper extremity and both lower extremities. What is the most likely cause of the change?

Explanation

The change noted is focal and confined to the cortex, sparing the opposite side, both lower extremities, and the subcortical waveforms, making all the choices unlikely with the exception of carotid compression with focal cortical ischemia. This may be associated with poor collateral flow from the opposite hemisphere due to an incomplete circle of Willis. Drummond JC, Englander RN, Gallo CJ: Cerebral ischemia as an apparent complication of anterior cervical discectomy in a patient with an incomplete circle of Willis. Anesth Analg 2006;102:896-899.

Question 19

A 68-year-old woman undergoes a complicated four-level anterior cervical diskectomy and fusion at C3-7 with iliac crest bone graft and instrumentation for multilevel cervical stenosis. Surgical time was approximately 6 hours and estimated blood loss was 800 mL. Neuromonitoring was stable throughout the procedure. The patient's history is significant for smoking. The most immediate appropriate postoperative management for this patient should include

Explanation

Airway complications after anterior cervical surgery can be a catastrophic event necessitating emergent intubation for airway protection. Multilevel surgeries requiring long intubation and prolonged soft-tissue retraction as well as preexisting comorbidities may predispose a patient to postoperative airway complications. Sagi and associates reported that surgical times greater than 5 hours, blood loss greater than 300 mL, and multilevel surgery at or above C3-4 are risk factors for airway complications. In surgical procedures with the aforementioned factors, serious consideration should be given to elective intubation for 1 to 3 days to avoid urgent reintubation. Sagi HC, Beutler W, Carroll E, et al: Airway complications associated with surgery on the anterior cervical spine. Spine 2002;27:949-953. Epstein NE, Hollingsworth R, Nardi D, et al: Can airway complications following multilevel anterior cervical surgery be avoided? J Neurosurg 2001;94:185-188.

Question 20

A 22-year-old woman reports a 4-year history of worsening low back and left lower extremity pain following a motor vehicle accident. Management consisting of physical therapy, chiropractic manipulation, and interventional pain management, including sacroiliac joint injections and epidural steroid injections, has failed to provide relief. A sagittal T2-weighted MRI scan is shown in Figure 8. No nerve root compression is seen on axial images. She is currently working and lives with her fiancé. She smokes half a pack of cigarettes per day and reports depression on her health history. She is being maintained on narcotic analgesics and is having increasing difficulty performing her activities of daily living secondary to pain. What is the most appropriate management at this time?

Explanation

The MRI scan reveals a rudimentary disk at the L5-S1 level, suggesting transitional anatomy. There is a posterior disk bulge at L3-4. At L4-5, there is disk desiccation and loss of disk height, with a posterior disk bulge and a high intensity zone in the posterior annulus, suggesting an annular tear. While these and similar radiographic findings have been associated with the severity of a patient's pain, they are also commonly found in cross-sectional studies of asymptomatic subjects. Carragee and associates found 59% of symptomatic patients undergoing diskography have high intensity zones as compared to 25% of asymptomatic subjects of a similar patient profile. Diskographic injections provoked pain in disks with high intensity zones approximately 70% of the time whether the individual was previously symptomatic or not. This patient's non-specific pain pattern does not require further work-up as she is not a surgical candidate. Carragee EJ, Paragioudakis SJ, Khurana S: 2000 Volvo Award winner in clinical studies: Lumbar high-intensity zone and discography in subjects without low back problems. Spine 2000;25:2987-2992. Pneumaticos SG, Reitman CA, Lindsey RW: Diskography in the evaluation of low back pain. J Am Acad Orthop Surg 2006;14:46-55. Brox JI, Sorensen R, Friis A, et al: Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine 2003;28:1913-1921.

Question 21

A 42-year-old man with a history of renal cell carcinoma has progressive weakness in the lower extremities for the past 3 weeks. The patient desires intervention. A sagittal T2-weighted MRI scan is shown in Figure 9a, and a sagittal contrast enhanced T1-weighted MRI scan is shown in Figure 9b. He currently ambulates minimal distances with a walker. His life expectancy is 8 months. Treatment of the spine lesion should consist of

Explanation

The MRI scans show a metastatic lesion in two contiguous vertebral bodies in the lower thoracic spine. Posterior laminectomy is not indicated because this does not adequately decompress the neural elements and will lead to progressive kyphosis. A posterior fusion may prevent progressive kyphosis but will not decompress the spinal cord. Renal cell carcinoma is not radiosensitive; therefore, radiation therapy would not be helpful in relieving neurologic compression. The lesion should be treated by an anterior corpectomy and reconstruction. This will allow for complete decompression as well as reconstruction of the anterior column. Kyphoplasty is not indicated in a lesion with disruption of the posterior cortex and neurologic impairment. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 351-366.

Question 22

A 40-year-old man has intractable pain following 2 years of nonsurgical management for high-grade spondylolisthesis. What is the best surgical option?

Explanation

Circumferential fusion is the preferred choice for patients undergoing revision surgery following failed posterolateral fusions for isthmic spondylolisthesis as well as for those patients having primary surgery for high-grade isthmic spondylolisthesis.

Question 23

An adult patient with a grade I isthmic spondylolisthesis at L5-S1 is most likely to have weakness of the

Explanation

Adult patients with isthmic spondylolisthesis most commonly have neurologic symptoms due to foraminal stenosis at the level of the spondylolisthesis. In this scenario, the patient is most likely to have weakness of the L5 myotome, which would cause weakness of the extensor hallucis longus. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 311-317.

Question 24

When performing a long fusion to the sacrum in an osteopenic patient in whom optimal sagittal balance is restored, which of the following is a benefit of extending the distal fixation to the pelvis, rather than the sacrum alone?

Explanation

In osteopenic individuals, even those with excellent obtained or maintained balance, long instrumented fusions to the sacrum impart a high degree of strain, and the sacrum may fail in a transverse fracture or fracture-dislocation pattern. The risk of proximal functional kyphosis is unrelated to distal fixation as are coronal plane correction and rod contouring. Pubic ramus fractures have been shown to be associated with both fixation to the sacrum alone as well as to the ilium.

Question 25

Which of the following statements describing chordomas is false?

Explanation

Casali and associates provided a recent review of the treatment options for chordomas. These tumors are not radiosensitive; however, modern intensity modulated radiosurgery techniques may be of value. The combination of surgery and radiotherapy compared to surgery alone results in the same disease-free survival time. Complete surgical resection of the chondroma with clean margins offers the best survival; however, its location may make total removal impossible. Thus subtotal resection followed by radiotherapy results in better survival despite the tumor's lack of radiosensitivity.

Question 26

A 35-year-old male sustains a T12 burst fracture after a fall from a height of 10 feet. He is neurologically intact. MRI demonstrates an indeterminate posterior ligamentous complex (PLC) injury. According to the Thoracolumbar Injury Classification and Severity (TLICS) scale, what is the most appropriate management recommendation?

Explanation

This patient has a TLICS score of 4 (Morphology: Burst = 2; Neuro: Intact = 0; PLC: Indeterminate = 2). A score of 4 signifies that either operative or nonoperative management is acceptable based on surgeon preference.

Question 27

Which of the following physical examination findings is most specific for cervical spondylotic myelopathy localizing to the C5 or C6 level?

Explanation

The inverted radial reflex is highly specific for a lesion at the C5-C6 level. It is elicited by tapping the brachioradialis tendon, resulting in paradoxical spontaneous flexion of the digits.

Question 28

A 65-year-old male presents with adult spinal deformity and severe sagittal imbalance. His pelvic incidence (PI) is calculated at 55 degrees. To achieve an optimal sagittal profile and minimize the risk of adjacent segment disease following a long-segment fusion, the patient's postoperative lumbar lordosis (LL) should be targeted to which of the following ranges?

Explanation

A key goal in adult spinal deformity correction is matching the lumbar lordosis to the pelvic incidence. Postoperative LL should ideally be within 10 degrees of the PI (PI = LL +/- 10 degrees).

Question 29

A 25-year-old male is brought to the emergency department after a motor vehicle collision. He is awake, alert, and follows commands. Neurological examination reveals intact motor and sensory function. Radiographs demonstrate a bilateral C5-C6 facet dislocation. What is the most appropriate next step in management?

Explanation

In an awake, cooperative, and neurologically intact patient, urgent closed reduction via skeletal traction is safe and indicated. MRI prior to reduction is generally reserved for patients who are comatose or unexaminable to rule out a compressive disc herniation.

Question 30

A 45-year-old female presents with severe right anterior thigh pain and quadriceps weakness. Physical examination reveals an absent right patellar reflex. MRI demonstrates a large, 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 herniation compresses the L4 nerve root.

Question 31

In a patient presenting with symptomatic L4-L5 degenerative spondylolisthesis and lumbar stenosis, which of the following MRI findings is most predictive of dynamic instability and the potential failure of decompression alone without fusion?

Explanation

Facet joint effusions >1.5 mm on T2-weighted MRI strongly correlate with dynamic instability on flexion-extension radiographs. These patients are at higher risk of progressive slip if treated with decompression alone.

Question 32

According to the Lenke Classification system for adolescent idiopathic scoliosis, a proximal thoracic curve is considered structural if a supine side-bending radiograph shows a residual Cobb angle of at least what magnitude?

Explanation

In the Lenke classification, minor curves are considered structural if they fail to bend out to less than 25 degrees on side-bending radiographs, or if there is a regional kyphosis of >20 degrees.

Question 33

An 80-year-old male sustains a hyperextension injury to his cervical spine resulting in central cord syndrome. What is the typical sequence of neurological recovery in this condition?

Explanation

Recovery in central cord syndrome typically occurs in a predictable sequence: lower extremities first, followed by bowel/bladder function, then proximal upper extremities. Distal upper extremity (hand intrinsic) function returns last and often has the poorest recovery.

Question 34

A 60-year-old male with long-standing ankylosing spondylitis presents with severe neck pain following a minor low-speed motor vehicle collision. Standard anteroposterior and lateral cervical radiographs demonstrate no obvious fracture or dislocation. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable occult fractures even after minor trauma. Plain radiographs are inadequate due to altered anatomy; a CT scan is mandatory if a fracture is suspected.

Question 35

Which of the following clinical findings is the most sensitive indicator for diagnosing cauda equina syndrome?

Explanation

Urinary retention is the most sensitive clinical sign (approximately 90%) for cauda equina syndrome. A normal post-void residual (PVR < 100 mL) makes the diagnosis highly unlikely.

Question 36

During a posterior spinal fusion for adolescent idiopathic scoliosis, transcranial motor evoked potentials (MEPs) drop by 85% bilaterally in the lower extremities following curve correction. Somatosensory evoked potentials (SSEPs) remain unchanged. Mean arterial pressure is 85 mmHg. What is the most appropriate initial step?

Explanation

Isolated loss of MEPs suggests anterior cord ischemia or motor pathway compromise. The immediate first step is to halt the procedure and release the corrective forces/rods to restore perfusion to the spinal cord.

Question 37

A 15-year-old male presents with hyperkyphosis of the thoracic spine. According to the Sorensen criteria, radiographic diagnosis of Scheuermann's disease requires anterior wedging of at least 5 degrees in how many consecutive vertebrae?

Explanation

The Sorensen criteria define classic Scheuermann's kyphosis as thoracic hyperkyphosis (>40 degrees) with anterior wedging of at least 5 degrees in three or more consecutive vertebrae.

Question 38

A 52-year-old male presents with radiating arm pain, numbness in the middle finger, and weakness in triceps extension and wrist flexion. Which cervical disc level is most likely herniated?

Explanation

These findings are classic for a C7 radiculopathy. In the cervical spine, the exiting nerve root corresponds to the lower vertebral segment, so a C6-C7 disc herniation affects the C7 nerve root.

Question 39

A 19-year-old female sustains a bony Chance fracture of L2 due to a lap-belt injury during a high-speed collision. Which of the following associated injuries is most commonly found in this patient population?

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of patients with these fractures have concomitant intra-abdominal injuries, most commonly involving hollow viscous organs like the small bowel.

Question 40

In patients with progressively increasing positive sagittal imbalance (e.g., flatback syndrome), the body attempts to compensate to maintain a horizontal gaze. Which of the following accurately describes the primary compensatory mechanisms?

Explanation

To compensate for anterior sagittal imbalance and maintain horizontal gaze, patients typically increase pelvic retroversion (which increases pelvic tilt), extend their hips, flex their knees, and hyperlordose their cervical spine.

Question 41

Which of the following historical features is most characteristic of neurogenic claudication associated with lumbar spinal stenosis, as opposed to vascular claudication?

Explanation

Neurogenic claudication typically improves with lumbar flexion (e.g., sitting, leaning forward, walking uphill) because flexion increases the cross-sectional area of the spinal canal. Vascular claudication worsens with exertion regardless of posture.

Question 42

An 82-year-old previously independent male presents with a displaced Type II odontoid fracture after a fall. Considering the morbidity associated with various treatments in the elderly, what is generally the most appropriate definitive management?

Explanation

In functionally independent elderly patients with displaced Type II odontoid fractures, posterior C1-C2 fusion is favored. Halo vest immobilization in patients >80 years old carries an unacceptably high risk of respiratory complications and mortality.

Question 43

Which of the following congenital spinal anomalies carries the highest risk for rapid curve progression, often necessitating early prophylactic surgical fusion?

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra has the highest rate of progression (often 5 to 10 degrees per year) because growth is tethered on one side and accelerated on the opposite convex side.

Question 44

When planning a long spinal fusion for adult degenerative scoliosis to restore sagittal balance, which fixed anatomical parameter is most critical for calculating the patient's target lumbar lordosis?

Explanation

Pelvic incidence (PI) is a fixed morphological parameter unique to each individual. Restoring lumbar lordosis to match the PI (ideally within 9 degrees) is the critical target for achieving optimal sagittal balance in deformity surgery.

Question 45

A 65-year-old man presents with severe cervical spondylotic myelopathy. Lateral radiographs reveal a fixed, rigid kyphotic deformity of 25 degrees from C3-C6.

Which of the following surgical approaches is contraindicated in this clinical scenario?

Explanation

In the setting of a fixed cervical kyphosis, an isolated posterior laminectomy is contraindicated because the spinal cord remains draped and compressed over the anterior pathological osteophytes. An anterior or combined approach is required to correct the deformity and indirectly decompress the cord.

Question 46

A unilateral cervical facet dislocation is most commonly produced by which of the following injury mechanisms?

Explanation

Unilateral facet dislocations classically result from a combined flexion and rotation mechanism. In contrast, bilateral facet dislocations are typically caused by a more severe flexion-distraction force.

Question 47

Which of the following components are utilized to calculate the Thoracolumbar Injury Classification and Severity (TLICS) score to guide surgical decision-making?

Explanation

The TLICS system determines the need for surgical stabilization based on three main categories: injury morphology (e.g., burst, translation), integrity of the posterior ligamentous complex (PLC), and the patient's neurologic status.

Question 48

A 12-year-old premenarchal girl (Risser 0) presents with Adolescent Idiopathic Scoliosis. Standing radiographs demonstrate a right thoracic curve of 32 degrees. What is the most appropriate management?

Explanation

A patient with significant growth remaining (premenarchal, Risser 0) and a curve between 25 and 45 degrees meets the classic indications for bracing. A TLSO worn for 16-23 hours a day is standard of care to halt progression.

Question 49

A 45-year-old man presents with right leg pain. MRI reveals a standard posterolateral (paracentral) disc herniation at the L4-L5 level. Which nerve root is most likely to be impinged?

Explanation

In the lumbar spine, a classic posterolateral (paracentral) disc herniation impinges the traversing nerve root. Therefore, a herniation at the L4-L5 level affects the L5 nerve root.

Question 50

A 16-year-old gymnast presents with chronic low back pain exacerbated by extension. Lateral radiographs demonstrate a grade I spondylolisthesis at L5-S1. What is the most likely underlying anatomic defect?

Explanation

Isthmic spondylolisthesis in adolescent athletes (especially those doing repetitive extension) is caused by a stress fracture or defect of the pars interarticularis (spondylolysis).

Question 51

An 82-year-old man sustains a Type II odontoid fracture after a ground-level fall. He is neurologically intact. When comparing treatment with a halo vest to a rigid cervical collar in this age group, halo vest immobilization carries a significantly higher risk of which of the following?

Explanation

In the elderly population, halo vest immobilization is associated with a markedly increased risk of complications, including respiratory failure, cardiac events, and overall mortality, compared to rigid collar treatment.

Question 52

A 65-year-old man with a long history of severe ankylosing spondylitis presents with new neck pain after a minor fall. Initial standard cervical spine radiographs show no acute abnormalities. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis have rigid, highly susceptible spines where even minor trauma can cause highly unstable, occult fractures. Advanced cross-sectional imaging (CT or MRI) is mandatory when they present with new pain, even if plain films are negative.

Question 53

A 70-year-old man presents to the emergency department after a motor vehicle collision. He exhibits upper extremity weakness (motor strength 2/5) but relatively preserved lower extremity function (motor strength 4/5). What is the most likely diagnosis?

Explanation

Central cord syndrome typically follows a hyperextension injury in a patient with pre-existing cervical stenosis. It classically presents with a disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 54

Which of the following represents the classic Sorensen radiographic criteria for diagnosing Scheuermann's kyphosis?

Explanation

The classic Sorensen criteria require the presence of anterior vertebral wedging of greater than 5 degrees in at least three consecutive vertebrae to diagnose Scheuermann's kyphosis.

Question 55

A 45-year-old woman presents with acute severe back pain, bilateral leg radiculopathy, and numbness in her perineal region. Which of the following is the most consistent and sensitive early symptom indicating cauda equina syndrome?

Explanation

Urinary retention is the most sensitive and consistent early symptom of cauda equina syndrome. It often precedes overflow incontinence and necessitates emergent MRI evaluation and decompression.

Question 56

During an anterior cervical exposure, injury to the vertebral artery is a catastrophic risk. The vertebral artery typically enters the transverse foramen at which cervical level?

Explanation

The vertebral artery typically arises from the subclavian artery and enters the transverse foramen of the cervical spine at the C6 level in approximately 90% of cases.

Question 57

According to the Lenke classification for adolescent idiopathic scoliosis, a minor curve is considered 'structural' and should generally be included in the fusion construct if it demonstrates which characteristic on side-bending radiographs?

Explanation

In the Lenke classification, a secondary or minor curve is defined as structural if it remains greater than or equal to 25 degrees on maximum voluntary side-bending radiographs.

Question 58

Following a rigid instrumented lumbar fusion, symptomatic adjacent segment disease most frequently develops at which location relative to the fusion construct?

Explanation

Adjacent segment disease most commonly occurs at the motion segment immediately rostral (cephalad) to a spinal fusion. This is attributed to altered biomechanics, increased lever arm, and concentrated stress at that un-fused level.

Question 59

A 22-year-old man wearing a lap belt only sustains a Chance fracture (flexion-distraction injury) of his L2 vertebra during a high-speed collision. Due to the specific mechanism of this injury, he is at highest risk for which concomitant injury?

Explanation

Chance fractures result from a flexion-distraction force typically pivoted around a lap belt. Up to 50% of these patients have associated intra-abdominal injuries, most commonly lacerations or ruptures of a hollow viscus (e.g., bowel).

Question 60

Which of the following is an FDA-recognized severe complication specifically associated with the off-label use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in anterior cervical discectomy and fusion (ACDF)?

Explanation

The use of rhBMP-2 in the anterior cervical spine has been linked to severe, life-threatening prevertebral soft tissue swelling, hematoma, and dysphagia, leading to an FDA safety warning against its routine use in this anatomical location.

Question 61

A 50-year-old man is diagnosed with a 'far lateral' (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is compressed by this specific type of herniation?

Explanation

Unlike paracentral herniations which affect the traversing root, a far lateral (extraforaminal) disc herniation compresses the exiting nerve root at the level of the disc. At L4-L5, this impinges the L4 nerve root.

Question 62

A 68-year-old man presents with bilateral upper extremity weakness and numbness after a hyperextension injury to his neck. His lower extremity motor function is mildly decreased but functionally intact. Perianal sensation is preserved. Which of the following is the most likely pathophysiological mechanism for this specific spinal cord syndrome?

Explanation

This patient has Central Cord Syndrome, most commonly caused by a hyperextension injury in a stenotic cervical spine. The central location of the injury disproportionately affects the medially located cervical motor tracts and anterior horn cells, leading to greater upper extremity weakness.

Question 63

A 14-year-old female gymnast presents with persistent low back pain unresponsive to 6 months of conservative management. Radiographs reveal a Grade II L5-S1 isthmic spondylolisthesis. What is the most appropriate surgical management?

Explanation

In adolescents with symptomatic low-grade isthmic spondylolisthesis failing conservative care, in situ posterolateral instrumented fusion of L5-S1 is the standard of care. Pars repairs are typically reserved for L1-L4 defects without a significant slip.

Question 64

Which of the following radiographic parameters defines an adequate restoration of sagittal balance following adult spinal deformity corrective surgery?

Explanation

Adequate sagittal alignment in adult spinal deformity is widely defined by a PI-LL mismatch of less than 10 degrees, an SVA less than 5 cm, and a PT less than 20 degrees. Proper restoration of these parameters improves health-related quality of life outcomes.

Question 65

A 35-year-old man sustains a flexion-distraction injury (Chance fracture) of the T12 vertebra during a high-speed motor vehicle collision. Which of the following associated injuries must be most carefully ruled out?

Explanation

Flexion-distraction injuries (Chance fractures) are frequently caused by seatbelt trauma and have a 40-50% association with intra-abdominal injuries. Hollow viscus injuries, particularly of the small bowel, are the most common associated finding.

Question 66

A 45-year-old man presents with severe right leg pain radiating down the anterior thigh to the medial malleolus. Examination reveals a weakened patellar reflex and 3/5 strength in right knee extension. MRI shows a far-lateral extraforaminal disc herniation. Which spinal level is most likely affected?

Explanation

A far-lateral (extraforaminal) disc herniation impinges the exiting nerve root at the same level. An L4-L5 far-lateral herniation affects the L4 nerve root, causing weakness in knee extension, anterior thigh pain, and a diminished patellar reflex.

Question 67

During the anterior placement of halo pins for cervical spine immobilization, the pins should be placed in the lateral one-third of the eyebrow to avoid injury to which of the following structures?

Explanation

The safe zone for anterior halo pin placement is the lateral one-third of the eyebrow, just above the equator of the skull. Medial placement risks injury to the supraorbital and supratrochlear nerves, frontal sinus, and supraorbital artery.

Question 68

A 75-year-old patient with ankylosing spondylitis presents to the emergency department with severe neck pain following a ground-level fall. Neurological examination is normal. Standard anteroposterior and lateral cervical radiographs show no clear fracture. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are highly susceptible to unstable cervical spine fractures even from low-energy trauma. A CT scan of the cervical spine is mandatory to rule out an occult fracture, as conventional radiographs are notoriously difficult to interpret in these patients.

Question 69

Which congenital spinal anomaly carries the highest risk for rapid scoliosis progression and typically warrants early prophylactic in situ fusion?

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra represents a complete failure of segmentation on one side and a failure of formation on the other. This creates a severe growth imbalance, leading to the highest risk of rapid curve progression.

Question 70

A 55-year-old woman undergoes a multilevel anterior cervical discectomy and fusion (ACDF) using recombinant human bone morphogenetic protein-2 (rhBMP-2). Postoperatively, she develops severe dysphagia and respiratory distress. This complication is most directly related to which of the following?

Explanation

The use of rhBMP-2 in the anterior cervical spine is associated with a significantly increased risk of severe prevertebral soft tissue swelling. This swelling can lead to life-threatening airway compromise and dysphagia, which prompted FDA warnings regarding its off-label use in ACDF.

Question 71

A 32-year-old construction worker presents with a burst fracture of L1 and bilateral lower extremity paraparesis. He is awake, alert, and hemodynamically stable. MRI demonstrates significant retropulsion of bone into the spinal canal. What is the most common indication for an anterior corpectomy and strut grafting over a purely posterior approach?

Explanation

Anterior corpectomy allows for direct decompression of the spinal canal. It is specifically indicated when posterior ligamentotaxis fails or is unable to adequately clear retropulsed bone fragments causing persistent neurological deficits.

Question 72

A 60-year-old man presents with neurogenic claudication secondary to severe lumbar spinal stenosis at L4-L5. Which of the following findings on history or physical examination best differentiates neurogenic claudication from vascular claudication?

Explanation

Neurogenic claudication is characteristically relieved by lumbar flexion (such as leaning over a shopping cart or sitting), which increases the spinal canal area. Vascular claudication is worsened by muscle exertion regardless of posture and is typically relieved by simply resting.

Question 73

A 65-year-old woman presents with worsening low back pain and a progressive forward-leaning posture while walking. Radiographs demonstrate degenerative lumbar scoliosis. Her measured pelvic incidence (PI) is 60 degrees. To achieve optimal sagittal balance postoperatively, what should her lumbar lordosis (LL) ideally be reconstructed to?

Explanation

Optimal sagittal balance in adult spinal deformity requires the lumbar lordosis (LL) to be matched within 10 degrees of the patient's pelvic incidence (PI). Therefore, for a PI of 60 degrees, the ideal LL should be approximately 60 degrees (acceptable range 50 to 70 degrees).

Question 74

A 65-year-old man with preexisting cervical spondylosis sustains a hyperextension injury during a motor vehicle collision. He presents with bilateral upper extremity weakness (3/5) but retains normal motor function (5/5) in his lower extremities. What is the most likely diagnosis?

Explanation

Central cord syndrome typically occurs in older patients with cervical spondylosis following hyperextension injuries. It causes disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 75

In the Thoracolumbar Injury Classification and Severity (TLICS) system, which of the following morphological patterns is assigned the highest point value?

Explanation

The TLICS system assigns 4 points to a distraction morphology, which is the highest score in the morphology category. Translation/rotation receives 3 points, burst 2, and compression 1.

Question 76

A 68-year-old woman presents with classic neurogenic claudication. MRI confirms severe L4-L5 central spinal stenosis associated with a grade 1 degenerative spondylolisthesis. She has failed 6 months of conservative treatment. What is the most appropriate surgical intervention?

Explanation

In patients with symptomatic lumbar spinal stenosis associated with degenerative spondylolisthesis, decompression combined with instrumented fusion provides better long-term clinical and radiographic outcomes compared to decompression alone.

Question 77

In the evaluation of adult spinal deformity, Pelvic Incidence (PI) is a fixed morphologic parameter. What is the anatomic formula relating Pelvic Incidence (PI), Pelvic Tilt (PT), and Sacral Slope (SS)?

Explanation

Pelvic Incidence is a fixed anatomical parameter defined as the sum of Pelvic Tilt and Sacral Slope (PI = PT + SS). It dictates the required lumbar lordosis for optimal sagittal balance.

Question 78

A 7-year-old boy presents with torticollis following an upper respiratory infection. Open mouth odontoid radiograph shows asymmetry of the lateral masses, consistent with Fielding Type 1 Atlantoaxial Rotatory Subluxation (AARS). What is the most appropriate initial management, given symptom onset was 3 days ago?

Explanation

Fielding Type 1 AARS (rotatory fixation without anterior displacement) presenting acutely (less than 1 week) is initially managed conservatively with a soft collar, NSAIDs, and muscle relaxants.

Question 79

A 60-year-old man with cervical spondylotic myelopathy is being considered for a posterior laminoplasty. Which of the following preoperative radiographic findings is a relative contraindication for this procedure?

Explanation

Cervical kyphosis greater than 10-13 degrees is a contraindication for laminoplasty. The spinal cord will not adequately drift posteriorly (the "bowstring effect") to relieve anterior compression in a kyphotic spine.

Question 80

An 82-year-old woman sustains a Type II odontoid fracture after a ground-level fall. She has multiple medical comorbidities, severe osteoporosis, and is minimally displaced. What is the most appropriate management strategy with the lowest associated mortality?

Explanation

In elderly patients with significant comorbidities, rigid cervical collar immobilization is often preferred for Type II odontoid fractures. Surgical intervention and halo vest use carry significantly higher morbidity and mortality in this population.

Question 81

According to the Lenke Classification for Adolescent Idiopathic Scoliosis, what specific radiographic criterion defines a "structural" proximal thoracic curve?

Explanation

In the Lenke classification, a minor curve is considered structural if it does not correct to less than 25 degrees on supine side-bending radiographs, or if there is a regional kyphosis of >20 degrees.

Question 82

Following a rigid lumbar fusion, adjacent segment degeneration (ASD) most commonly occurs at which specific anatomic level?

Explanation

Adjacent segment degeneration most commonly occurs at the level immediately cranial to the fused spinal segment. This is driven by increased biomechanical stress and altered kinematics at the unfused junction.

Question 83

A 35-year-old man presents with a complete C5 spinal cord injury after a diving accident. He is awake and cooperative. Imaging shows bilateral C5-C6 facet dislocations without massive disc herniation. What is the most urgent next step in management?

Explanation

For awake, cooperative patients with acute cervical facet dislocations and neurologic deficits, immediate closed reduction via cranial traction is the standard of care to decompress the spinal cord rapidly. MRI should not delay urgent closed reduction.

Question 84

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

Explanation

The classic Sorenson criteria for diagnosing Scheuermann's disease require anterior wedging of at least 5 degrees in three or more consecutive vertebral bodies.

Question 85

A patient presents with severe right anterior thigh pain and weakness in knee extension. An MRI reveals a far lateral (extraforaminal) disc herniation at the L3-L4 level. Which nerve root is most likely compressed?

Explanation

In the lumbar spine, a far lateral (extraforaminal) disc herniation impinges the exiting nerve root at that level. At the L3-L4 level, the exiting root is L3.

Question 86

A 72-year-old man with advanced ankylosing spondylitis presents with severe back pain after a minor ground-level fall. Initial plain radiographs are inconclusive. What is the next most appropriate imaging modality, and what fracture pattern is highly suspected?

Explanation

Patients with ankylosing spondylitis are highly susceptible to unstable extension-distraction ("chalk stick") fractures even from low-energy trauma. A CT scan of the entire spine is the most appropriate next step due to the high risk of occult fractures.

Question 87

What is the most common anatomic level for an isthmic spondylolisthesis, and which patient population most frequently presents with symptoms?

Explanation

Isthmic spondylolisthesis most commonly occurs at the L5-S1 level due to a pars interarticularis defect. It classically presents symptomatically in adolescent athletes subjected to repetitive hyperextension (e.g., gymnasts).

Question 88

A 25-year-old man sustains a gunshot wound to the abdomen. The bullet traverses the colon and lodges in the L3 vertebral body. He is completely neurologically intact. In addition to broad-spectrum antibiotics, what is the recommended orthopedic management for the spine?

Explanation

For retained bullets in the spine without neurologic deficit, surgical extraction is generally not indicated, even if the bullet passed through the colon. Broad-spectrum antibiotics (for 7-14 days) and observation are standard.

Question 89

A 45-year-old man presents with sudden onset saddle anesthesia, bilateral sciatica, and urinary retention. A post-void residual (PVR) bladder volume is measured. What minimum PVR volume is considered highly sensitive for urinary retention associated with cauda equina syndrome?

Explanation

A post-void residual (PVR) > 200 mL is highly sensitive for the urinary retention associated with cauda equina syndrome. This finding should prompt urgent MRI and surgical decompression.

Question 90

At what Risser stage and Cobb angle is rigid brace treatment typically indicated for Adolescent Idiopathic Scoliosis (AIS)?

Explanation

Bracing for AIS is indicated in skeletally immature patients (Risser 0-2, pre-menarchal) with a Cobb angle between 25 and 40 degrees, or documented curve progression of 5 degrees in curves between 20 and 25 degrees.

Question 91

According to the Denis classification of sacral fractures, which zone injury carries the highest risk of accompanying neurologic deficit?

Explanation

Denis Zone 3 sacral fractures involve the central sacral canal and carry the highest risk of neurologic injury (up to 57%), frequently affecting bowel, bladder, and sexual function.

Question 92

A patient complains of neck pain radiating down the lateral arm to the thumb and index finger. Physical examination reveals a diminished brachioradialis reflex and weakness in wrist extension. Which cervical nerve root is most likely compressed?

Explanation

A C6 radiculopathy classically presents with sensory deficits in the thumb and index finger, weakness in wrist extension and elbow flexion, and a diminished brachioradialis reflex.

Question 93

Iatrogenic flatback syndrome is most commonly historically associated with which of the following prior surgical interventions?

Explanation

Iatrogenic flatback syndrome classically resulted from the use of long distraction instrumentation (such as Harrington rods) extending down to the lower lumbar spine or sacrum, effectively obliterating normal lumbar lordosis.

Question 94

A 25-year-old male presents to the trauma bay after a motor vehicle collision. He is awake, alert, and cooperative. Examination reveals a complete lack of motor and sensory function below C6 (ASIA A). Radiographs demonstrate a bilateral facet dislocation at C5-C6. What is the most appropriate initial management?

Explanation

In an awake, cooperative patient with a cervical spine facet dislocation, urgent closed reduction using cranial traction is the standard of care. An MRI is not a prerequisite before closed reduction in an examinable patient and should not delay attempts to decompress the spinal cord.

Question 95

A 68-year-old female presents with neurogenic claudication. Imaging reveals an L4-L5 degenerative spondylolisthesis. Which of the following anatomic or radiographic findings is most strongly associated with the development of this condition?

Explanation

Degenerative spondylolisthesis at L4-L5 is highly associated with sagittal orientation of the facet joints (>45 degrees relative to the coronal plane), which allows forward slippage of the vertebra. Pars defects cause isthmic, not degenerative, spondylolisthesis.

Question 96

A 14-year-old female with adolescent idiopathic scoliosis (AIS) has a right main thoracic curve of 52 degrees and a left lumbar curve of 34 degrees. On side-bending radiographs, the thoracic curve corrects to 30 degrees and the lumbar curve corrects to 15 degrees. Thoracic kyphosis (T5-T12) is +15 degrees. According to the Lenke classification, what is the appropriate curve type and recommended fusion approach?

Explanation

This is a Lenke 1 curve because the main thoracic curve is structural (>25 degrees on bending) while the lumbar curve is nonstructural (<25 degrees on bending). The standard surgical treatment for a Lenke 1 curve is a selective thoracic fusion, sparing the lumbar spine.

Question 97

A 65-year-old woman is planning to undergo corrective surgery for progressive adult spinal deformity and sagittal imbalance. To achieve optimal postoperative sagittal alignment and minimize the risk of adjacent segment disease or hardware failure, the surgeon must calculate the target lumbar lordosis (LL). Which of the following formulas represents the accepted target for LL based on her pelvic incidence (PI)?

Explanation

In adult spinal deformity correction, the target lumbar lordosis should generally match the patient's pelvic incidence within 9 to 10 degrees (PI - LL < 10 degrees). Failing to adequately restore this relationship significantly increases the risk of persistent sagittal imbalance and revision surgery.

Question 98

A 58-year-old male of East Asian descent presents with progressive myelopathy. CT scan shows continuous ossification of the posterior longitudinal ligament (OPLL) from C3 to C6. The cervical spine has maintained lordosis, and on a neutral sagittal image, the OPLL mass does not cross the K-line (K-line positive). What is the most appropriate surgical intervention?

Explanation

Posterior cervical laminoplasty is highly effective and generally preferred for K-line positive OPLL with maintained cervical lordosis, avoiding the higher complication rates of anterior surgery. Anterior approaches are typically reserved for K-line negative cases or severe kyphotic deformities where posterior drift of the cord will not occur.

Question 99

A 32-year-old male falls 10 feet, sustaining an L1 burst fracture. He is neurologically intact (ASIA E). A non-contrast MRI confirms that the posterior ligamentous complex (PLC) is completely intact. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is the patient's score and the recommended management?

Explanation

The TLICS score is calculated as follows: Burst fracture morphology = 2 points, Neurologically intact = 0 points, Intact PLC = 0 points. A total score of 2 indicates that nonoperative management (such as bracing) is recommended.

Question 100

A 62-year-old man undergoes a complex 10-hour posterior spinal fusion for adult deformity correction, with an estimated blood loss of 2500 mL. On postoperative day 1, he complains of profound, bilateral, painless visual loss. Pupillary reflexes are sluggish, and funduscopic examination reveals pale, swollen optic discs. What is the most likely etiology?

Explanation

Ischemic optic neuropathy (ION) is the most common cause of postoperative vision loss in spine surgery, particularly following long operations in the prone position with significant blood loss. Unlike central retinal artery occlusion, ION is typically bilateral, painless, and is not primarily caused by direct pressure on the globe.

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

AAOS Spine Surgery MCQs (Set 1): Spinal Trauma, Degenerative Disc & Deformity

Key Takeaway

AAOS Spine Surgery MCQs (Set 1): Spinal Trauma, Degenerative Disc & Deformity

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