ABOS Spine MCQs (Set 2): Degenerative Lumbar Questions

Question 1

A previously healthy 35-year-old man was involved in a rollover motor vehicle accident 2 days ago. He was placed in a semi-rigid cervical orthosis. He now reports mostly axial neck pain with attempted range of motion. Examination reveals the mechanical neck pain but no obvious neurologic deficits. AP, flexion, and extension radiographs are shown in Figures 10a through 10c, and sagittal and coronal CT scans are shown in Figures 10d and 10e. What is the most appropriate management at this time?

Explanation

10b 10c 10d 10e Odontoid fractures can be classified based on the anatomic position of the fracture within the dens itself. Type I is an oblique fracture through the upper part of the odontoid process. Type II is a fracture that occurs at the base of the odontoid as it attaches to the body of C2; type III occurs when the fracture line extends through the body of the axis. Type 1 fractures typically can be treated nonsurgically with 6 to 8 weeks of immobilization with a semi-rigid cervical orthosis. Nondisplaced, deep type III fractures generally are treated with skeletal halo fixation. Deep, displaced, and angled type III fractures can be treated with closed reduction and skeletal halo fixation. Shallow type III fractures are sometimes amenable to anterior odontoid screw fixation. Type II fractures can be managed nonsurgically or surgically. Treatment options include halo immobilization, internal fixation (odontoid screw fixation), and posterior atlantoaxial arthrodesis. Management with the halo vest usually is considered if the initial dens displacement is less than 6 mm, the reduction is performed within 1 week of the injury and is able to be maintained, and the patient is younger than age 60 years. Halo vest immobilization can lead to a healing rate of more than 90%. Posterior surgical fusion techniques provide high fusion success rates but do so at the expense of cervical rotation. Up to 50% of rotation is lost with these techniques. Anterior odontoid single screw fixation is often tolerated better than skeletal halo fixation and also is noted to preserve the normal rotation at C1/C2. Studies have shown less of a malunion and nonunion rate in the treatment of type II odontoid fractures with anterior odontoid screw fixation. Osteoporosis, short neck and barrel-chested anatomy, and fractures that are more than 4 weeks old preclude anterior odontoid fixation. Shilpakar S, McLaughlin MR, Haid RW Jr, et al: Management of acute odontoid fractures: Operative techniques and complication avoidance. Neurosurg Focus 2000;8:e3. Subach BR, Morone MA, Haid RW Jr, et al: Management of acute odontoid fractures with single-screw anterior fixation. Neurosurgery 1999;45:812-819.

Question 2

Which of the following palpable bony landmarks is correctly matched with its corresponding vertebral level?

Explanation

The carotid tubercle is usually located at the level of C6. The angle of the mandible is at C1-C2; the hyoid is at C4; the superior portion of the thyroid cartilage is C4-C5; and the cricoid cartilage is at C6. Smith GW, Robinson RA: The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am 1958;40:607.

Question 3

What root is most commonly involved with a segmental root level palsy after laminoplasty?

Explanation

The postoperative incidence of C5 root palsy after laminoplasty ranges from 5% to 12%. Other roots also may be affected. The palsies tend to be motor dominant, although sensory dysfunction and radicular pain are also possible. The palsy may arise during the immediate postoperative period or up to 20 days later. C5 may be preferentially involved because it is at the apex of the cervical lordosis. Recovery usually occurs over weeks to months. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 235-249.

Question 4

Up to what time frame are the risks minimized in anterior revision disk replacement surgery?

Explanation

Revision anterior exposure within 2 weeks of total disk replacement incurs relatively little additional morbidity because adhesion formation is minimal. Surgeons should have a low threshold for revising implants that are clearly dangerously malpositioned or show early migration within this 2-week window. Beyond this time period, a revision strategy must be individualized to the particular clinical situation. A posterior fusion with instrumentation with or without a laminectomy is currently the most effective salvage procedure.

Question 5

Which of the following best describes the use of epidural morphine and steroid paste after laminectomy?

Explanation

Kramer and associates conducted a retrospective review during an "epidemic" period to identify the risk factors associated with a sudden increase in the rate of surgical site infections. They found in a multivariate analysis that the use of morphine nerve paste resulted in a 7.6-fold increase in postoperative surgical wound debridement, and an 11% rate of surgical site complications. Kramer MH, Mangram AJ, Pearson ML, et al: Surgical-site complications associated with a morphine nerve paste used for postoperative pain control after laminectomy. Infect Control Hosp Epidemiol 1999;20:183-186.

Question 6

Figures 11a and 11b show the T2-weighted MRI scans of the lumbar spine of a 53-year-old woman who has low back and right lower extremity pain. What structure is the arrow pointing to in Figure 11a?

Explanation

11b The arrow is pointing to a cystic-appearing structure with high signal intensity on T2-weighted image sequencing. It appears to be contiguous with the hypertrophied right facet joint, which appears to also have high signal intensity. The mass significantly narrows the right lateral recess. The high signal intensity suggests that this is a fluid-filled mass. In addition, the facet joints are degenerative and there is a very mild degree of anterolisthesis on the sagittal image. These findings make a lumbar synovial cyst the most likely diagnosis. Most lumbar juxtafacet cysts are observed at the L4-5 level, extradurally and adjacent to the degenerative facet joint. They may contain synovial fluid and/or extruded synovium. Presentation is indistinguishable from that of a herniated disk. The etiology of spinal cysts remains unclear, but there appears to be a strong association between their formation and worsening spinal instability. They occasionally regress spontaneously and may respond to aspiration and injection of corticosteroids, though there is a high recurrence rate with nonsurgical management. Synovial cysts resistant to nonsurgical management should be treated surgically. If the patient's symptoms can be attributable to radicular findings, a microsurgical decompression that limits further destabilization should suffice. However, if there is significant low back pain attributable to spinal instability, decompression and fusion remains an appropriate option. Banning CS, Thorell WE, Leibrock LG: Patient outcome after resection of lumbar juxtafacet cysts. Spine 2001;26:969-972. Deinsberger R, Kinn E, Ungersbock K: Microsurgical treatment of juxta facet cysts of the lumbar spine. J Spinal Disord Tech 2006;19:155-160.

Question 7

A 38-year-old man reports a 2-week history of acute lower back pain with radiation into the left lower extremity. There is no history of trauma and no systemic signs are noted. Examination reveals a positive straight leg test at 35 degrees on the left side and a contralateral straight leg raise on the right side. Motor testing demonstrates mild weakness of the gluteus medius and weakness of the extensor hallucis longus of 3+/5. Sensory examination demonstrates decreased sensation along the lateral aspect of the calf and top of the foot. Knee and ankle reflexes are intact and symmetrical. Radiographs demonstrate no obvious abnormality. MRI scans show a posterolateral disk hernation. The diagnosis at this time is consistent with a herniated nucleus pulposus at

Explanation

The patient's history and physical examination findings are consistent with a lumbar disk herniation at the L4-5 level. Weakness of the extensor hallucis longus and gluteus medius are consistent with an L5 lumbar radiculopathy. Nerve root tension signs are also consistent with sciatica from a lumbar disk herniation. The MRI scans confirm a posterolateral disk herniation at L4-5, which typically affects the exiting L5 nerve root. Hoppenfeld S: Orthopedic Neurology. Philadelphia, PA, JB Lippincott, 1977, pp 45-74.

Question 8

A 42-year-old woman is brought to the emergency department following a motor vehicle accident. She has sustained multiple injuries, and she is intubated and pharmacologically paralyzed. Sagittal cervical CT scans through the right cervical facets, the left cervical facets, and the midline are shown in Figures 12a through 12c, respectively. Definitive management of her cervical injury should consist of

Explanation

12b 12c The CT scans reveal an occipital-cervical dissociation with subluxation of the occipitocervical joints bilaterally. Definitive management should consist of an occipital-cervical fusion with instrumentation. Immobilization in a Philadelphia collar is inadequate for this highly unstable injury, and halo immobilization, while affording adequate temporary immobilization, is not appropriate definitive management for this ligamentous injury. The patient does not have an injury at C4-C5 or C6-C7. Jackson RS, Banit DM, Rhyne AL III, et al: Upper cervical spine injuries. J Am Acad Orthop Surg 2002;10:271-280.

Question 9

A 32-year-old motorcycle rider is involved in a motor vehicle accident and radiographs show a burst fracture at L2 with 20 degrees of kyphosis. The neurologic examination is consistent with unilateral motor and sensory involvement of the L5, S1, S2, S3, and S4 nerve roots. He has no other injuries. CT demonstrates 20% anterior canal compromise with displaced laminar fractures at the level of injury. What is the best option for management of this patient?

Explanation

The patient has a burst fracture with probable unilateral entrapment of the cauda equina within the elements of the fractured lamina. A dural tear is likely in this scenario as well. It is recommended that this type of burst fracture be treated surgically with laminectomy, freeing of the entrapped nerve roots, and dural repair followed by stabilization of the fracture by either a posterior or combined approach. The degree of kyphosis and the extent of anterior canal compromise does not warrant corpectomy in this patient. Therefore, after completing the laminectomy and dural repair, posterior fusion and instrumentation should be sufficient to stabilize the fracture. Cammisa FP Jr, Eismont FJ, Green BA: Dural laceration occurring with burst fractures and associated laminar fractures. J Bone Joint Surg Am 1989;71:1044-1052.

Question 10

A patient who underwent a L4-L5 hemilaminotomy and partial diskectomy for radiculopathy 8 weeks ago now reports increasing low back pain without neurologic symptoms. A sagittal T2-weighted MRI scan is shown in Figure 13a, and a contrast enhanced T1-weighted MRI scan is shown in Figure 13b. What is the most appropriate management for the patient's symptoms?

Explanation

13b The MRI scans show Modic changes in the L4-L5 vertebral bodies due to spondylosis. There is no increased fluid signal or enhancement in the L4-L5 disk to suggest infection or any other pathologic process. Therefore, the patient's pain should be treated with a course of physical therapy and rehabilitation. There is no infection; therefore, IV antibiotics and debridement are not indicated. Similarly, a pseudomeningocele is not present. A revision diskectomy is useful for recurrent radiculopathy but would not be helpful for degenerative low back pain. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 319-329.

Question 11

What is the heaviest weight that can be safely applied to the adult cervical spine via Gardner-Wells tong traction?

Explanation

Cotler and associates reported on the use of awake skeletal traction to reduce facet fracture-dislocations in 24 patients. Seventeen patients required more than 50 pounds of traction (the "traditional" limit) to achieve reduction. More than 100 pounds of traction was safely used in one-third of the patients in this study. A cadaver study has supported the safe use of traction with weights in excess of 100 pounds. Cotler JM, Herbison GJ, Nasuti JF, et al: Closed reduction of traumatic cervical spine dislocation using traction weights up to 140 pounds. Spine 1993;18:386-390.

Question 12

A 68-year-old man reports a 4-week history of progressive left-sided lower back and hip pain. The pain is in the posterior buttock region with radiation to the groin and to the left anterior knee region. The pain is aggravated with walking and improves with rest. There is no history of previous trauma. Radiographs are seen in Figures 14a and 14b, and MRI scans are seen in Figures 14c through 14e. What is the most appropriate treatment option at this time?

Explanation

14b 14c 14d 14e Although the imaging reveals generalized lumbar spondylosis and stenosis, in particular at L4-5, the MRI scan of the left hip clearly reveals a stress fracture of the femoral neck. Therefore, the treatment of choice is non-weight-bearing of the left lower extremity. During the evaluation of acute back pain, clinicians must include other possibilities within the differential diagnosis that may mimic mechanical axial back pain; thus, potential complications from a missed diagnosis can be avoided. Wong DA, Transfeldt E: Macnab's Backache, ed 4. Philadelphia, PA, Lippincott Williams and Wilkins, 2007, pp 339-361.

Question 13

A 79-year-old woman reports a history of left leg pain with walking. Her pain is exacerbated with walking and stair climbing, and her symptoms are improved by standing after she stops walking. Lumbar flexion does not provide any significant improvement of the symptoms and sitting does not significantly change symptoms. Her leg pain is worse at night and she obtains relief by hanging her leg over the side of the bed. The neurologic examination is essentially normal. Examination of the lower extremities demonstrates mild early trophic changes, and her pulses distally are palpable but are diminished bilaterally. Radiographs are shown in Figures 15a and 15b. What is the next most appropriate step in management?

Explanation

15b The patient has symptoms that are more consistent with vascular claudication than with the pseudoclaudication anticipated from lumbar spinal stenosis. Therefore, the patient is a candidate for further vascular work-up. The radiographs reveal early spinal stenosis and spondylolisthesis at L4-5 but also show significant calcification of the iliac arteries, suggestive of peripheral vascular disease. Vascular claudication is a manifestation of peripheral vascular disease and presents with crampy leg pain that is exacerbated by physical exertion. The pain is easily relieved by standing still or sitting. Unlike pseudoclaudication, a forward-flexed posture and/or sitting does not improve the symptoms. Night pain is common in vascular claudication due to the elevation of the extremities and patients often report pain improvement by hanging their extremities in a dependent position. In evaluation of a patient with suspected vascular claudication, the five "P's" of vascular insufficiency should be monitored, including pulselessness, paralysis, paresthesia, pallor, and pain. While pain and paresthesias can be common in both vascular claudication and pseudoclaudication, the presence of any of the remaining symptoms is suggestive of vascular disease. Aufderheide TP: Peripheral arteriovascular disease, in Rosen P, Barkin R (eds): Emergency Medicine: Concepts and Clinical Practice, ed 4. St Louis, MO, Mosby, 1998, pp 1826-1844.

Question 14

Figure 16 shows the MRI scan of a 43-year-old man who has had worsening low back pain for the past 4 months. What is the most likely diagnosis?

Explanation

Tuberculosis of the spine is seen in 50% to 60% of skeletal disease and is most commonly found in the lower thoracic or upper lumbar spine. Typically two or more adjacent bodies are involved as seen in this MRI scan. The disk space is narrowed but still relatively preserved as opposed to pyogenic infections (black arrow). Epidural extensions often spread from vertebrae to vertebrae (white arrow); however, the posterior elements are not frequently involved (arrowhead). Tumors rarely spread to adjacent vertebrae. The anterior and posterior spread of the infectious process rules out trauma. Boachie-Adjei O, Squillante RG: Tuberculosis of the spine. Orthop Clin North Am 1996;27:95-103.

Question 15

In patients without spondylolisthesis or scoliosis undergoing laminectomy for lumbar spinal stenosis, spinal fusion is generally recommended if

Explanation

With the notable exception of fusion for degenerative spondylolisthesis and scoliosis, there is a paucity of evidence on the indications for spinal fusion in patients undergoing laminectomy for spinal stenosis. However, it is generally recommended that if the spine is destabilized (for example by removal of one complete facet joint or by an iatrogenic pars fracture), spinal fusion should be considered. Although fusion can be considered for a very long laminectomy, a two-level laminectomy does not represent, by itself, a clear indication for the addition of a spinal fusion. The repair of a dural tear and the use of nicotine by the patient play no role in the determination of whether or not to add fusion to a laminectomy procedure. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 299-409.

Question 16

An 18-year-old collegiate basketball player has had a 3-month history of activity-related back pain. She describes isolated low back pain without radiation that increases with training and playing basketball. Her pain resolves with rest. Physical therapy for 6 weeks has failed to provide relief. An axial CT scan is shown in Figure 17a, and Figures 17b and 17c show sagittal CT reconstructions through the right and left lumbar facets, respectively. Further management should consist of which of the following?

Explanation

17b 17c The sagittal and axial CT scans show a bilateral spondylolysis at L5. The defect is in the pars interarticularis on the right side but at the base of the pedicle on the left. Having failed a trial of physical therapy with only a 3-month history of pain, the next most appropriate step in management should consist of activity modification and bracing in an antilordotic lumbosacral orthosis. Surgical intervention is reserved for patients who have failed to respond to a trial of bracing and activity restriction. Debnath UK, Freeman BJ, Grevitt MP, et al: Clinical outcome of symptomatic unilateral stress injuries of the lumbar pars interarticularis. Spine 2007;32:995-1000.

Question 17

Radiating pain associated with a posterolateral thoracic disk herniation typically follows what pattern?

Explanation

Although symptomatic thoracic disk herniations can affect more caudal structures, even to the point of paralysis, the pattern of radiating pain has been described as either following the dermatomal band around the chest or feeling to the patient as if the pain passes straight anteriorly to the chest wall.

Question 18

A 53-year-old man reports a 5-week history of worsening low back pain accompanied by bilateral knee and ankle pain and swelling. He also reports a lesser degree of neck and left elbow pain. He denies any history of trauma or provocative episodes. His medical history is significant for Reiter's syndrome more than 25 years ago, with no subsequent exacerbations. Furthermore, he has recently returned from a vacation in Costa Rica and noted the development of infectious gastroenteritis with diarrhea within 1 week of his return. This was treated with a 10-day course of oral antibiotics and has since resolved. He denies any significant bowel or urinary symptoms at this time. His neurologic examination is essentially within normal limits, but is somewhat limited by his low back and leg pain. What further investigation is most appropriate at this time?

Explanation

The patient has pain involving the cervical and lumbar spine as well as pain and swelling in both the knees and ankles. As such, this can be classified as polyarticular arthritis. The presence of multiple joint symptoms in the lower extremities, the absence of a history of trauma, and the multiple joints involved direct attention away from the spine as the etiology of this patient's pain. Radiographs of the involved joints are not likely to yield much useful information to assist with a diagnosis. Likewise, an MRI scan of the lumbar spine is not likely to provide much information regarding the etiology of the patient's condition. When a rheumatologic illness is suspected, the selective use of confirmatory laboratory testing can aid in arriving at a correct diagnosis. A presumed case of gout or chondrocalcinosis can be confirmed by the presence of the appropriate crystals in a joint-fluid aspiration. Because of the patient's recent trip to Costa Rica and the subsequent gastroenteritis, a CBC count, ESR, and CRP should be ordered to rule out infectious and inflammatory versus noninflammatory conditions. Rheumatoid factor (RF) in general should only be ordered for patients with polyarticular joint inflammation for more than 6 weeks. The presence of rheumatoid factor does not indicate rheumatoid arthritis. Antinuclear antibodies (ANA) should be ordered when a connective tissue disease such as systemic lupus erythematosus (SLE) is suspected on the basis of specific history and physical examination findings, such as inflammatory arthritis. Human leukocyte antigen-B27 (HLA-B27) should be ordered only when the patient's history is compatible with ankylosing spondylitis or Reiter's syndrome and this patient had a history of Reiter's syndrome. Gardner GC, Kadel NJ: Ordering and interpreting rheumatologic laboratory tests. J Am Acad Orthop Surg 2003;11:60-67.

Question 19

The 5-year outcome for patients with sciatica secondary to lumbar disk herniation shows which of the following results?

Explanation

Atlas and associates, in the Maine Lumbar Spine Study, reported that overall, patients treated initially with surgery reported better outcomes. By 5 years, 19% of surgical patients had undergone at least one additional lumbar spine operation, and 16% of nonsurgical patients had opted for at least one lumbar spine operation. At the 5-year follow-up, 70% of patients initially treated surgically reported improvement in their predominant symptom (back or leg pain) versus 56% of those initially treated nonsurgically. They also noted that there was no difference in the proportion of patients receiving disability compensation at the 5-year follow-up.

Question 20

What is one of the principle concerns when a fracture such as the one seen in Figure 18 is encountered?

Explanation

The injury shown is a fracture-dislocation and it is highly unstable. In addition to this concern, spinal epidural hematomas have a much higher incidence in people with ankylosing spondylitis following knee fracture. It is felt to be due to disrupted epidural veins, with hypervascular epidural soft tissue in the setting of a rigid spinal canal. Patients with ankylosing spondylitis may have other significant comorbidities, especially cardiac and pulmonary, and these should be carefully assessed. Ludwig S, Zarro CM: Complications encountered in the management of patients with ankylosing spondylitis, in Vaccaro AR, Regan JJ, Crawford AH, et al (eds): Complications of Pediatric and Adult Spine Surgery. New York, NY, Marcel Dekker, 2004, pp 279-290.

Question 21

Retrograde ejaculation is most commonly associated with what surgical approach?

Explanation

Retrograde ejaculation is the sequela of an injury to the superior hypogastric plexus. This structure needs protection, especially during anterior exposure of the lumbosacral junction. Although the superior hypogastric plexus can be injured with anterior or anterolateral spine surgery at any lumbar level, it is most at risk with anterior transperitoneal approaches to the lumbosacral junction. To avoid this complication, the use of monopolar electrocautery should be avoided during deep dissection in this region. The ideal anterior exposure starts with blunt dissection just to the medial aspect of the left common iliac vein sweeping the prevertebral tissues toward the patient's right side. Flynn JC, Price CT: Sexual complications of anterior fusion of the lumbar spine. Spine 1984;9:489-492. Watkins RG (ed): Surgical Approaches to the Spine. New York, NY, Springer-Verlag, 1983, p 107.

Question 22

What nerve is most likely to be injured during the anterior exposure of C2-3?

Explanation

The hypoglossal nerve exits from the ansa cervicalis at approximately the C2-3 level and can be injured during retraction up to the C2 level. The superior laryngeal nerve lies at about C4-5. The facial nerve is much higher. The vagus nerve runs with the internal jugular and carotid much more laterally. The phrenic nerve exits posteriorly. Chang U, Lee MC, Kim DH: Anterior approach to the midcervical spine, in Kim DH, Henn JS, Vaccaro AR, et al (eds): Surgical Anatomy and Techniques to the Spine. Philadelphia, PA, Saunders Elsevier, 2006, pp 45-54.

Question 23

A 24-year-old man sustains the injury shown in Figures 19a through 19e in a paragliding accident. He is neurologically intact. He also sustained fractures of his left femur and right distal radius. Which of the following represents the best option for management of the spinal injury?

Explanation

19b 19c 19d 19e The injury pattern is that of a burst fracture at L1 contiguous with a compression fracture at T12. There is associated kyphosis and slight spondylolisthesis of T12 on L1. Treatment of this type of burst fracture in neurologically intact patients is somewhat controversial, with at least one study demonstrating equal long-term results comparing nonsurgical treatment to surgical treatment. In this study, however, body casts were used initially in the nonsurgical group. Moreover, because this patient has multiple fractures, spinal fracture stabilization should be considered to facilitate early mobilization. Surgical stabilization and fusion via a posterior approach is the best treatment option in this patient. Anterior decompression is not necessary since the patient is neurologically intact. McLain RF, Benson DR: Urgent surgical stabilization of spinal fractures in polytrauma patients. Spine 1999;24:1646-1654. Wood K, Butterman G, Mehbod A, et al: Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit: A prospective, randomized study. J Bone Joint Surg Am 2003;85:773-781.

Question 24

An 82-year-old man is seen in consultation after being admitted for a fall from ground level. There was no loss of consciousness and the patient recalls striking his head and sustaining a hyperextension-type injury to the cervical spine. Examination reveals an 8-cm head laceration with only mild axial neck tenderness. He has generalized weakness throughout the upper extremities and maintained motor function of the lower extremities. There are no obvious sensory deficits, and the bulbocavernous reflex and deep tendon reflexes are maintained. What is the most appropriate diagnosis at this time?

Explanation

Incomplete cord syndromes have variable neurologic findings with partial loss of sensory and/or motor function below the level of injury. Incomplete cord syndromes include the anterior cord syndrome, the Brown-Séquard syndrome, central cord syndrome, and posterior cord syndrome. Central cord syndrome is characterized with greater motor weakness in the upper extremities than in the lower extremities. The pattern of motor weakness shows greater distal involvement in the affected extremity than proximal muscle weakness. Anterior cord syndrome involves a variable loss of motor function and pain and/or temperature sensation, with preservation of proprioception. The Brown-Séquard syndrome involves a relatively greater ipsilateral loss of proprioception and motor function, with contralateral loss of pain and temperature sensation. Posterior cord syndrome is a rare injury and is characterized by preservation of motor function, sense of pain, and light touch, with loss of proprioception and temperature sensation below the level of the lesion. Spinal shock is the period of time, usually 24 hours, after a spinal injury that is characterized by absent reflexes, flaccidity, and loss of sensation below the level of the injury. Penrod LE, Hegde SK, Ditunno JF: Age effect on prognosis for functional recovery in acute, traumatic central cord syndrome. Arch Phys Med Rehab 1990;71:963-968.

Question 25

Kyphosis from a vertebral osteoporotic compression fracture often results in progressive kyphosis due to

Explanation

Kayanja and associates, in a number of biomechanical studies, showed that in a kyphotic spine the strain is located at the apex of the deformity, the force is transmitted to the superior adjacent vertebrae, and that realignment and cement augmentation effectively normalize the load transfer. Kayanja MM, Ferrara LA, Lieberman IH: Distribution of anterior cortical shear strain after a thoracic wedge compression fracture. Spine J 2004;4:76-87. Kayanja MM, Togawa D, Lieberman IH: Biomechanical changes after the augmentation of experimental osteoporotic vertebral compression fractures in the cadaveric thoracic spine. Spine J 2005;5:55-63. Kayanja MM, Schlenk R, Togawa D, et al: The biomechanics of 1, 2, and 3 levels of vertebral augmentation with polymethylmethacrylate in multilevel spinal segments. Spine 2006;31:769-774.

Question 26

A 32-year-old man presents with severe neck pain and right arm weakness (deltoid and biceps) after a mountain biking accident. He is awake, alert, and cooperative. Plain radiographs demonstrate a right-sided C4-C5 unilateral facet dislocation. What is the most appropriate next step in his management?

Explanation

In an awake and cooperative patient with a cervical facet dislocation and an acute neurologic deficit, immediate closed reduction via cranial traction is indicated. MRI can be delayed until after reduction is achieved to prevent prolonged spinal cord or nerve root compression.

Question 27

A 68-year-old man with a known history of severe cervical spondylosis falls forward and strikes his chin, sustaining a hyperextension injury. He presents with profound bilateral upper extremity weakness (hands greater than shoulders) and relatively preserved lower extremity strength. What is the most likely neurologic diagnosis?

Explanation

Central cord syndrome typically occurs following a hyperextension injury in older adults with pre-existing cervical spondylosis. It characteristically presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 28

An 82-year-old woman falls from a standing height. CT imaging reveals a Type II odontoid fracture with 2 mm of posterior displacement. She has no neurologic deficits but has a history of congestive heart failure and severe COPD. What is the most appropriate management?

Explanation

In elderly patients with Type II odontoid fractures and significant medical comorbidities, rigid cervical collar immobilization is generally preferred. Both surgical intervention and halo vest immobilization carry disproportionately high morbidity and mortality in this specific patient population.

Question 29

A 45-year-old man develops severe right leg pain radiating to the dorsum of his foot. On examination, he has 3/5 weakness in the extensor hallucis longus and decreased sensation over the first dorsal web space. His patellar and Achilles reflexes are intact. Which of the following disc herniations is most likely responsible?

Explanation

An L4-L5 paracentral disc herniation compresses the traversing L5 nerve root. This presents clinically with extensor hallucis longus weakness and sensory deficits over the dorsal aspect of the foot.

Question 30

A 60-year-old man undergoes an uncomplicated C3-C6 laminectomy and posterior fusion for cervical myelopathy. Two days postoperatively, he develops new-onset isolated right deltoid weakness (2/5) with intact sensation and no lower extremity changes. An urgent MRI shows a well-decompressed cord with no hematoma. What is the most likely diagnosis?

Explanation

C5 nerve root palsy is a known complication following posterior cervical decompression, believed to be caused by posterior spinal cord shift and subsequent tethering of the short C5 nerve root. Treatment is typically supportive, and many patients recover spontaneously over time.

Question 31

A 65-year-old woman presents with severe neurogenic claudication and an L4-L5 degenerative spondylolisthesis. She has failed 6 months of conservative management. According to classical literature, which surgical treatment provides the lowest rate of reoperation and best clinical outcome?

Explanation

For degenerative spondylolisthesis accompanied by symptomatic stenosis, a decompressive laminectomy combined with instrumented fusion has traditionally demonstrated better long-term clinical outcomes and lower reoperation rates compared to laminectomy alone.

Question 32

A 30-year-old man dives into a shallow pool and sustains a burst fracture of C1 (Jefferson fracture). On the open-mouth odontoid radiograph, the sum of the lateral mass displacement of C1 over C2 is measured at 8 mm. What does this finding indicate?

Explanation

According to Spence's rule, a combined lateral mass overhang of C1 on C2 greater than 6.9 mm on an AP radiograph strongly suggests a rupture of the transverse ligament. This renders the C1 ring fracture highly unstable.

Question 33

A 72-year-old man presents with deteriorating handwriting, difficulty buttoning his shirt, and a wide-based, unsteady gait. Which of the following physical exam findings is most specific for the likely diagnosis?

Explanation

The patient's symptoms are classic for cervical spondylotic myelopathy. A positive Hoffmann sign indicates an upper motor neuron lesion and is highly suggestive of cervical myelopathy in this clinical context.

Question 34

A 25-year-old man is involved in a motor vehicle accident. CT reveals a traumatic spondylolisthesis of the axis with C2 pars fractures. There is 4 mm of translation and 15 degrees of angulation of C2 on C3. What is the Levine-Edwards classification and the most appropriate initial management?

Explanation

A Levine-Edwards Type IIA fracture is characterized by severe angulation with minimal translation. Cervical traction is strictly contraindicated as it can cause over-distraction and neurologic injury; management involves gentle extension and halo vest immobilization.

Question 35

A 55-year-old man complains of severe right leg radicular pain. MRI demonstrates a synovial cyst arising from the L4-L5 facet joint, compressing the right L5 nerve root. If non-operative management fails, what is the most appropriate definitive surgical intervention?

Explanation

Lumbar facet cysts strongly indicate underlying segmental instability. Therefore, decompression and cyst excision combined with a spinal fusion provide the most definitive treatment and carry the lowest risk of cyst recurrence.

Question 36

A pedestrian is struck by a vehicle and is intubated at the scene. Lateral cervical spine radiographs show a basion-dental interval (BDI) of 14 mm. What is the most appropriate management for this patient?

Explanation

A basion-dental interval (BDI) greater than 12 mm is diagnostic of atlanto-occipital dissociation. Traction is absolutely contraindicated due to the risk of fatal spinal cord distraction, and definitive treatment requires an occipitocervical fusion.

Question 37

A 50-year-old man has severe left leg pain radiating down his anterior thigh. Exam reveals 3/5 strength in knee extension and an absent patellar reflex. MRI confirms a disc herniation. Based on the clinical presentation, what is the level and location of the herniation?

Explanation

The patient exhibits classic signs of an L4 radiculopathy (anterior thigh pain, quadriceps weakness, absent patellar reflex). A far lateral disc herniation at L4-L5 compresses the exiting L4 nerve root.

Question 38

A 40-year-old man is brought in comatose (GCS 6) following a high-speed collision. CT imaging demonstrates a unilateral C5-C6 facet dislocation. What is the most appropriate next step in the management of his cervical spine?

Explanation

In an obtunded or unexaminable patient with a cervical facet dislocation, an MRI must be obtained before attempting closed or open reduction. This ensures there is no herniated disc that could extrude into the spinal canal and cause catastrophic cord injury during reduction.

Question 39

A 62-year-old woman presents with new neurogenic claudication 5 years after an L3-L5 posterior spinal fusion. Radiographs show a new Grade 1 spondylolisthesis at L2-L3. What biomechanical consequence of her prior surgery most directly contributed to this adjacent segment disease?

Explanation

Spinal fusion successfully eliminates motion at the arthrodesis site, which unavoidably shifts mechanical stress to adjacent segments. This leads to increased mobility, elevated intradiscal pressure, and accelerated facet degeneration at those levels.

Question 40

A 42-year-old man presents to the emergency department with acute bilateral leg weakness, perianal numbness, and urinary retention with a post-void residual volume of 400 mL. MRI confirms a massive L4-L5 central disc extrusion. What is the optimal surgical timing to maximize his neurologic recovery?

Explanation

Cauda equina syndrome is an absolute surgical emergency. Emergent decompression within 24 to 48 hours (and optimally within 24 hours) is critical to maximize the recovery of bladder, bowel, and sexual function.

Question 41

A 55-year-old woman complains of chronic axial low back pain. MRI of her lumbar spine shows high signal intensity on both T1-weighted and T2-weighted images in the vertebral body endplates at L4-L5. What do these changes represent?

Explanation

Modic Type 2 changes appear hyperintense on both T1 and T2 MRI sequences. They represent the fatty degeneration of the subchondral bone marrow resulting from chronic degenerative disc disease.

Question 42

A 28-year-old man presents with complete quadriplegia following a diving accident. Lateral cervical radiographs reveal a C5-C6 bilateral facet dislocation. What is the primary mechanism of this specific injury?

Explanation

Bilateral cervical facet dislocations result predominantly from a severe hyperflexion and distraction force. This mechanism severely disrupts the posterior ligamentous complex and often leads to catastrophic spinal cord injury.

Question 43

An 82-year-old man presents with neck pain after a ground-level fall. CT scan reveals a Type II odontoid fracture with 2 mm of posterior displacement. He has a history of severe COPD, ischemic heart disease, and osteoporosis. Neurologic examination is completely normal. What is the most appropriate initial management?

Explanation

In elderly patients with severe comorbidities, isolated Type II odontoid fractures are typically managed with a rigid cervical collar. Surgical intervention and halo vests carry a prohibitively high morbidity and mortality risk in this demographic, making fibrous nonunion an acceptable outcome.

Question 44

A 25-year-old man is brought to the emergency department after a shallow water diving accident. He complains of severe neck pain but is completely neurologically intact, alert, and cooperative. Imaging demonstrates a bilateral C5-C6 facet dislocation. What is the most appropriate next step in management?

Explanation

For an awake, testable, and neurologically intact patient with a cervical facet dislocation, immediate closed reduction with traction is indicated to relieve spinal canal compromise. An MRI is required prior to reduction only if the patient is unexaminable or fails closed reduction.

Question 45

A 55-year-old woman presents with severe, acute right anterior thigh pain and new-onset weakness in her right leg. MRI demonstrates a right-sided far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed, and what specific physical exam finding is expected?

Explanation

A far lateral (extraforaminal) disc herniation at the L4-L5 level compresses the exiting L4 nerve root. Clinical findings of an L4 radiculopathy include anterior thigh pain, quadriceps weakness, and a diminished patellar reflex.

Question 46

A 42-year-old man presents to the emergency department with a 12-hour history of bilateral lower extremity weakness, saddle anesthesia, and urinary retention after lifting a heavy box. A bladder scan reveals a post-void residual volume of 450 mL. MRI confirms a massive L4-L5 central disc herniation. What is the most appropriate definitive management?

Explanation

Cauda equina syndrome is an orthopedic emergency requiring urgent surgical decompression. Current literature supports definitive decompression within 24 to 48 hours of symptom onset to optimize the recovery of bladder and bowel function.

Question 47

A 68-year-old man complains of bilateral calf and buttock pain that worsens with walking. He states the pain is reliably relieved by sitting down or leaning forward on a shopping cart, but does not resolve if he simply stops walking and stands still. Examination reveals diminished ankle reflexes but palpable pedal pulses. Which of the following is the most likely diagnosis?

Explanation

Neurogenic claudication due to lumbar spinal stenosis is classically exacerbated by lumbar extension (standing, walking) and relieved by lumbar flexion (sitting, shopping cart sign). Conversely, vascular claudication resolves rapidly with simple standing rest.

Question 48

A 65-year-old woman presents with classic neurogenic claudication. Radiographs reveal a grade 1 degenerative spondylolisthesis at L4-L5 with intact pars interarticularis. Which anatomic factor is the primary stabilizer preventing the progression of this specific slip?

Explanation

Sagittally oriented facet joints are a primary anatomic risk factor and determinant in the development and progression of degenerative spondylolisthesis, which most frequently occurs at the L4-L5 level.

Question 49

A 50-year-old man with a long-standing history of ankylosing spondylitis is involved in a low-speed motor vehicle collision. He reports new-onset neck pain but no neurologic deficits. Initial standard plain radiographs of the cervical spine are interpreted as normal. What is the most appropriate next step in his workup?

Explanation

Patients with ankylosing spondylitis have a rigid, brittle spinal column and are at high risk for highly unstable, occult extension fractures even from minor trauma. A complete CT scan of the cervical spine is mandatory when assessing these patients, as plain films are often inadequate.

Question 50

A 35-year-old construction worker presents with sudden lower neck pain after forcefully shoveling heavy debris. Examination reveals focal tenderness over the prominent spinous process at the cervicothoracic junction. Radiographs demonstrate an isolated oblique fracture of the C7 spinous process. What is the most appropriate management?

Explanation

A Clay Shoveler's fracture is a stable avulsion fracture of the lower cervical or upper thoracic spinous processes, typically C6, C7, or T1. Because it does not compromise spinal stability, management consists entirely of symptomatic care and activity modification.

Question 51

A 72-year-old man with known preexisting cervical spondylosis falls forward, striking his chin and sustaining a hyperextension injury to his neck. He presents with profound motor weakness in his hands and arms, but is able to move his legs relatively well against resistance. He also has urinary retention. What is the most likely diagnosis?

Explanation

Central cord syndrome is classically seen in elderly patients with preexisting cervical stenosis who sustain a hyperextension injury. It manifests with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 52

A 40-year-old man presents after a motor vehicle collision with 3/5 strength in left wrist extension and elbow extension. Radiographs show 25% anterior translation of C5 on C6. MRI reveals a unilateral facet dislocation and a large, extruded disc herniation posterior to the C5-C6 disc space causing cord compression. What is the most appropriate management?

Explanation

In the setting of a cervical facet dislocation with a large herniated disc, an anterior approach (ACDF) is indicated to remove the disc before or during reduction. Closed reduction or a posterior-only approach risks displacing the disc further into the spinal cord, leading to catastrophic neurologic injury.

Question 53

A 65-year-old man with a history of ankylosing spondylitis falls from a standing height. He complains of severe neck pain but has a normal neurologic examination. Initial lateral cervical spine radiographs are difficult to interpret due to lower cervical anatomy overlap and preexisting deformity. What is the most appropriate next step in imaging?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable cervical spine fractures even from low-energy trauma. Due to altered anatomy and osteopenia, a high-resolution CT scan is the gold standard and most appropriate next step to definitively rule out a fracture.

Question 54

A 45-year-old woman presents with sudden onset of severe low back pain, bilateral lower extremity weakness, and perineal numbness after lifting a heavy box. Her post-void residual bladder volume is 300 mL. MRI reveals a massive L4-L5 central disc herniation. Which of the following statements regarding the timing of surgical intervention is most accurate?

Explanation

Cauda equina syndrome is a surgical emergency. Decompression performed within 48 hours of symptom onset has been shown to result in better functional outcomes, particularly regarding bowel and bladder function, compared to decompression performed after 48 hours.

Question 55

A 55-year-old man presents with a right foot drop following an acute episode of back pain. Which physical examination finding would best differentiate an L5 radiculopathy from a common peroneal nerve entrapment at the fibular head?

Explanation

The tibialis posterior muscle (ankle inversion) is innervated by the tibial nerve (L4, L5) and is unaffected in a common peroneal nerve palsy. Weakness in ankle inversion alongside a foot drop indicates a more proximal lesion, such as an L5 radiculopathy.

Question 56

A 32-year-old man is involved in a motor vehicle accident. He complains of right-sided arm pain and exhibits weakness in elbow flexion and wrist extension. Radiographs demonstrate an anterolisthesis of C5 on C6 of approximately 25%. What is the most likely diagnosis?

Explanation

An anterolisthesis of approximately 25% (less than 50%) of the vertebral body width is classically associated with a unilateral facet dislocation. Bilateral facet dislocations typically present with greater than 50% displacement.

Question 57

A 70-year-old man with preexisting cervical spondylosis falls forward and strikes his forehead. He presents with bilateral upper extremity weakness that is worse distally, with relatively spared lower extremity motor function and preserved perianal sensation. What is the most likely pathophysiological mechanism of his neurological deficit?

Explanation

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

Question 58

A 68-year-old woman presents with severe bilateral leg and buttock pain that worsens with walking and prolonged standing, but improves when she leans forward over a shopping cart. Which of the following is the most consistent MRI finding for her condition?

Explanation

The clinical presentation describes neurogenic claudication secondary to lumbar spinal stenosis. The most common underlying MRI findings are degenerative changes including ligamentum flavum hypertrophy, facet arthropathy, and disc bulging.

Question 59

An 82-year-old woman sustains a Type II odontoid fracture after a ground-level fall. She is neurologically intact. If she is treated non-operatively with a hard cervical collar, which of the following is the most significant risk factor for nonunion?

Explanation

In the management of Type II odontoid fractures, initial fracture displacement greater than 5 mm, angulation greater than 10 degrees, and advanced age are significant risk factors for nonunion.

Question 60

Which of the following radiographic measurements on a lateral cervical spine film is most indicative of an atlanto-occipital dissociation?

Explanation

A Basion-Dental Interval (BDI) greater than 12 mm on plain radiographs or CT is highly suggestive of atlanto-occipital dissociation. An ADI > 3 mm suggests transverse ligament injury, not occipitocervical dissociation.

Question 61

A 60-year-old man underwent an L4-L5 posterior spinal fusion 5 years ago. He now presents with new-onset severe L3 radiculopathy. MRI demonstrates L3-L4 spinal stenosis and a new degenerative spondylolisthesis. What biomechanical factor most likely contributed to this new pathology?

Explanation

Adjacent segment disease occurs due to increased biomechanical stress and compensatory hypermobility at the spinal levels immediately adjacent to a fused segment. This accelerates degenerative changes, stenosis, and instability at the adjacent level.

Question 62

A 65-year-old female presents with neurogenic claudication and an L4-L5 grade I degenerative spondylolisthesis. She has failed 6 months of conservative management. According to the SPORT trial, what is the expected outcome of surgical decompression and fusion compared to continued non-operative treatment at 4 years?

Explanation

The Spine Patient Outcomes Research Trial (SPORT) demonstrated that patients with degenerative spondylolisthesis and spinal stenosis who were treated surgically had significantly greater improvement in pain and function compared to those treated non-operatively.

Question 63

A 25-year-old male sustains a severe hyperflexion injury to the cervical spine. He is awake, alert, and cooperative, but presents with a C6 ASIA A spinal cord injury. Radiographs show a bilateral facet dislocation at C6-C7. What is the most appropriate initial management in the trauma bay?

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation, closed skeletal traction is safe and effective for rapid reduction to decompress the spinal cord. It should be performed urgently with serial neurologic exams.

Question 64

A 40-year-old man presents with a C4-C5 fracture-dislocation following an accident. He complains of severe neck pain but has an intact neurologic examination. Which finding on a non-contrast cervical spine CT most strongly warrants obtaining a CT angiogram of the neck?

Explanation

Fractures extending into the transverse foramen, facet dislocations, and significant subluxations are high-risk mechanisms for blunt vertebral artery injury. A CT angiogram is indicated to evaluate for vertebral artery dissection or occlusion.

Question 65

A 50-year-old man presents with severe, burning anterior thigh pain and weakness in knee extension. Examination reveals a diminished patellar reflex. MRI demonstrates a far-lateral (extraforaminal) disc herniation at the L3-L4 level. Which nerve root is primarily being compressed?

Explanation

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

Question 66

During an L4-L5 laminectomy for severe spinal stenosis, an incidental dural tear occurs. It is successfully repaired primarily with a 4-0 non-absorbable suture, and a Valsalva maneuver demonstrates a watertight seal. What is the most appropriate postoperative management protocol?

Explanation

Recent literature shows that prolonged bed rest following primary, watertight repair of an incidental dural tear does not decrease the rate of subsequent CSF leaks. Early mobilization as tolerated is recommended and reduces complications associated with prolonged immobility.

Question 67

A 28-year-old male is comatose (GCS 6) following a high-speed motorcycle collision. A high-quality multi-detector CT scan of the cervical spine with sagittal and coronal reconstructions reveals no fractures or malalignment. According to current trauma guidelines, what is the appropriate next step regarding his cervical collar?

Explanation

Current guidelines, including those from EAST, state that a normal high-quality CT scan of the cervical spine is sufficient to clear the cervical spine in an obtunded or unexaminable trauma patient. Routine MRI or maintaining the collar is no longer recommended.

Question 68

A 45-year-old male is brought to the emergency department after a motor vehicle collision. He is awake, alert, and cooperative. Neurologic examination reveals an incomplete quadriparesis (ASIA C). Cervical spine radiographs demonstrate a bilateral facet dislocation at C5-C6. What is the most appropriate next step in management?

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation and a neurologic deficit, immediate closed cranial traction reduction is indicated to decompress the spinal cord. MRI is not required prior to reduction in a cooperative patient who can provide reliable neurologic exams during the procedure.

Question 69

Based on the outcomes of the Spine Patient Outcomes Research Trial (SPORT), which of the following statements is most accurate regarding the surgical treatment of degenerative spondylolisthesis with spinal stenosis?

Explanation

The SPORT trial demonstrated that patients treated surgically for degenerative spondylolisthesis with spinal stenosis maintained significantly greater improvement in pain and function at 4 years compared to those treated nonoperatively. Decompression with fusion is generally preferred over decompression alone to prevent progressive instability.

Question 70

An 82-year-old male presents with severe neck pain following a ground-level fall. CT of the cervical spine reveals a Type II odontoid fracture with 2 mm of posterior displacement. He is neurologically intact but has multiple medical comorbidities, including severe COPD and congestive heart failure. What is the most appropriate initial management?

Explanation

In elderly patients (typically >80 years) with multiple medical comorbidities, rigid cervical collar immobilization is the preferred initial treatment for Type II odontoid fractures. Surgery and halo vest immobilization carry exceptionally high morbidity and mortality in this specific patient population.

Question 71

A 65-year-old male presents with severe right leg pain. MRI demonstrates a far lateral (extra-foraminal) disc herniation at the L4-L5 level on the right. Which nerve root is most likely compressed, and what corresponding physical examination finding is expected?

Explanation

A far lateral (extra-foraminal) disc herniation at L4-L5 compresses the exiting L4 nerve root. This results in L4 radiculopathy, characterized by weakness in quadriceps (affecting knee extension) and anterior tibialis (ankle dorsiflexion), along with a diminished patellar reflex.

Question 72

A 70-year-old man with known cervical spondylosis falls forward and strikes his chin, hyperextending his neck. He presents with profound bilateral upper extremity weakness (especially in the hands) but is still able to ambulate with assistance. He has patchy sensory deficits. What is the most likely diagnosis?

Explanation

Central cord syndrome typically occurs after a hyperextension injury in patients with preexisting cervical spondylosis. It classically presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities, along with variable sensory loss.

Question 73

Which of the following findings is considered the most reliable indicator for early diagnosis of cauda equina syndrome in a patient presenting with acute low back pain and bilateral radiculopathy?

Explanation

Urinary retention is the most consistent and often the earliest sign of cauda equina syndrome. A post-void residual volume greater than 200-500 mL in the setting of acute low back pain and radiculopathy is highly suspicious and warrants emergent MRI.

Question 74

A 25-year-old male sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following a motor vehicle collision. Radiographs show significant angular deformity but minimal translation, and the C2-C3 disc space is widened posteriorly. According to the Levine and Edwards classification, this is a Type IIa fracture. What is the appropriate initial management?

Explanation

Type IIa Hangman's fractures involve severe angulation with minimal translation and indicate a flexion-distraction injury with an incompetent C2-C3 disc. Traction is strictly contraindicated as it will worsen the deformity; they should be reduced with gentle compression and extension in a halo vest.

Question 75

A 45-year-old female presents with persistent, severe lower back and bilateral L5 radicular pain that has failed 6 months of conservative management. Radiographs demonstrate a Grade II isthmic spondylolisthesis at L5-S1. What is the most appropriate surgical intervention?

Explanation

In adult patients with symptomatic low-grade isthmic spondylolisthesis failing conservative care, the standard surgical treatment is decompression of the neural elements combined with an instrumented posterolateral fusion (with or without interbody fusion). Pars repair is generally reserved for young patients (under 20) with minimal slip.

Question 76

A 30-year-old male sustains a Jefferson burst fracture of C1. On the open-mouth odontoid radiograph, the lateral masses of C1 are displaced laterally relative to the lateral masses of C2. According to Spence's rule, a combined lateral mass overhang exceeding what value suggests an incompetent transverse atlantal ligament?

Explanation

Spence's rule states that a combined overhanging of the C1 lateral masses on C2 of 6.9 mm or greater on an AP open-mouth radiograph indicates a rupture of the transverse atlantal ligament. Subsequent MRI studies have suggested that >8.1 mm may be more accurate, but 6.9 mm remains the classic threshold tested on boards.

Question 77

A 68-year-old male complains of bilateral posterior leg pain and heaviness that worsens with walking. Which of the following historical or physical examination findings most reliably differentiates neurogenic claudication from vascular claudication?

Explanation

Neurogenic claudication is classically relieved by lumbar flexion (e.g., leaning on a shopping cart, cycling), which opens the spinal canal and neuroforamina. Vascular claudication is typically relieved simply by resting or standing still, regardless of spinal posture.

Question 78

A 22-year-old male is involved in a rugby tackle resulting in a neck injury. Lateral cervical radiographs demonstrate a unilateral facet dislocation at C5-C6. What is the typical radiographic appearance of a unilateral facet dislocation regarding vertebral body translation?

Explanation

Unilateral facet dislocations typically exhibit less than 25% anterior translation of the superior vertebral body over the inferior body on lateral radiographs. Bilateral facet dislocations typically present with 50% or greater anterior translation.

Question 79

In the Subaxial Cervical Spine Injury Classification (SLIC) system, which of the following parameters assigns the highest point value towards the total score?

Explanation

In the SLIC system, an incomplete neurologic deficit is assigned 3 points, which is the highest score in the neurologic status category (Complete deficit = 2 points, Root injury = 1 point). This highlights the urgency and potential for recovery in incomplete cord injuries.

Question 80

A 35-year-old trauma patient undergoes an L4-L5 laminectomy and medial facetectomy for severe lateral recess stenosis. During the decompression, an incidental durotomy occurs. What is the most appropriate immediate management of this complication?

Explanation

The most appropriate immediate management of an intraoperative incidental durotomy is a primary, water-tight suture repair. This minimizes the risk of cerebrospinal fluid leak, pseudomeningocele formation, and persistent postural headaches.

Question 81

A 28-year-old patient suffers a severe hyperflexion injury to the cervical spine resulting in Anterior Cord Syndrome. Which of the following modalities will remain intact below the level of the injury?

Explanation

Anterior cord syndrome involves damage to the anterior two-thirds of the spinal cord, leading to loss of motor function (corticospinal tracts) and pain/temperature sensation (spinothalamic tracts). The posterior columns are spared, preserving proprioception, vibration, and fine touch.

Question 82

MRI of the lumbar spine in a 55-year-old patient with chronic mechanical low back pain reveals Modic Type 2 changes at the L4-L5 endplates. What histologic process do Modic Type 2 changes represent?

Explanation

Modic Type 2 changes on MRI (high signal on T1, high signal on T2) represent fatty replacement of the red subchondral bone marrow. Modic Type 1 represents fibrovascular/edematous changes (low T1, high T2), and Type 3 represents sclerosis (low T1, low T2).

Question 83

A 60-year-old woman presents with severe neurogenic claudication. MRI reveals severe central and lateral recess stenosis at L3-L4. Which nerve root is most likely compressed within the lateral recess at this level?

Explanation

In the lumbar spine, lateral recess stenosis at a given disc level compresses the traversing nerve root, which has not yet exited the foramen. At the L3-L4 level, the traversing root is L4. The exiting root (L3) would be affected by foraminal or extraforaminal compression.

Question 84

A patient arrives intubated and comatose (Glasgow Coma Scale score of 6) after a rollover MVC. Lateral radiographs demonstrate a bilateral facet dislocation at C6-C7. Before any attempt at closed reduction is made, what is the most critical next step?

Explanation

In a comatose or uncooperative patient with a cervical facet dislocation, an MRI of the cervical spine is mandatory prior to reduction to rule out a herniated disc. Reduction in the presence of a disc herniation in a patient unable to provide a neurologic exam can cause catastrophic spinal cord injury.

Question 85

Which of the following fracture patterns in the cervical spine carries the highest risk of concomitant vertebral artery injury, warranting screening with a CTA or MRA?

Explanation

Vertebral artery injuries in the cervical spine are most highly associated with flexion-distraction injuries (facet subluxations/dislocations) and fractures that extend through the transverse foramen, particularly in the subaxial spine.

Question 86

Which of the following factors represents the highest risk for nonunion of a Type II odontoid fracture treated nonoperatively with a rigid orthosis or halo vest?

Explanation

Risk factors for nonunion in Type II odontoid fractures include initial displacement > 5 mm, posterior displacement, angulation > 10 degrees, and age > 50 years. Displacement greater than 5 mm significantly decreases the bony apposition needed for successful healing.

Question 87

A 50-year-old male undergoes posterior lumbar decompression and fusion for degenerative spondylolisthesis. When placing pedicle screws, understanding the pedicle anatomy is critical. What anatomical structure forms the medial border of the lumbar pedicle?

Explanation

The medial border of the lumbar pedicle is adjacent to the dural sac. The superior border is the exiting nerve root, the inferior border is the traversing nerve root, and the lateral border is the paraspinal musculature and retroperitoneal space.

Question 88

A 24-year-old male presents after a motor vehicle accident with right upper extremity weakness. Examination shows 3/5 wrist extension and triceps strength. CT reveals a right-sided C6-C7 unilateral facet dislocation. MRI confirms a large extruded disc herniation behind the C6 body compressing the spinal cord. What is the most appropriate surgical management?

Explanation

In the setting of a cervical facet dislocation with an associated large anterior disc herniation compressing the cord, an anterior approach (ACDF) is required first. Closed reduction or a posterior-only approach can inadvertently pull the extruded disc further into the spinal canal, exacerbating neurologic injury.

Question 89

A 55-year-old male complains of severe anterior thigh pain and new-onset weakness in knee extension. MRI shows a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed by this specific herniation pattern?

Explanation

A far lateral or extraforaminal disc herniation compresses the exiting nerve root at that specific level. At the L4-L5 level, the exiting root is L4, leading to quadriceps weakness, depressed patellar reflex, and anterior thigh pain.

Question 90

An 82-year-old male with severe COPD and ischemic heart disease falls from a standing height. Imaging reveals a Type II odontoid fracture with 2 mm of posterior displacement. He is neurologically intact. What is the most appropriate management for this patient?

Explanation

In frail elderly patients with significant medical comorbidities, rigid cervical collar immobilization is the preferred treatment for Type II odontoid fractures. Surgery and halo vest immobilization both carry prohibitively high morbidity and mortality rates in this specific population, and nonunions are frequently asymptomatic and stable.

Question 91

A 68-year-old female presents with neurogenic claudication. Flexion/extension radiographs demonstrate an L4-L5 grade I degenerative spondylolisthesis that increases from 4 mm to 5 mm of translation. MRI confirms severe central canal stenosis. Which of the following findings most strongly supports performing a concomitant fusion rather than decompression alone?

Explanation

A sagittally oriented facet joint (angle > 45 degrees) is a significant biomechanical risk factor for progressive instability and slip progression following a laminectomy alone. Concomitant fusion is highly indicated in these patients to prevent postoperative failure.

Question 92

A 65-year-old male with pre-existing cervical spondylosis presents after a hyperextension injury. Examination demonstrates 2/5 motor strength in the upper extremities and 4/5 strength in the lower extremities. MRI shows increased T2 signal in the central spinal cord at C3-C4 without fracture or acute instability. What is the most appropriate initial management?

Explanation

This patient has classic Central Cord Syndrome. Initial management is medical and includes strict hemodynamic support to maintain spinal cord perfusion (MAP > 85 mmHg) to prevent secondary ischemic injury. Urgent surgical intervention is generally reserved for progressive neurologic deterioration.

Question 93

A 60-year-old female underwent an L5-S1 posterior instrumented spinal fusion 5 years ago. She now presents with new-onset left-sided foot drop and pain radiating down the lateral aspect of her leg to the dorsum of her foot. MRI demonstrates severe new lateral recess stenosis at the L4-L5 adjacent segment. Which nerve root is most likely affected?

Explanation

Central or lateral recess stenosis at the L4-L5 level compresses the traversing L5 nerve root. L5 radiculopathy clinically presents with weakness in ankle dorsiflexion (foot drop) and extensor hallucis longus, along with pain radiating to the dorsum of the foot.

Question 94

According to the Subaxial Cervical Spine Injury Classification (SLIC) system, which of the following morphologic injury patterns is assigned the highest point value?

Explanation

In the SLIC scoring system, Translation/Rotation injuries (such as facet dislocations) are considered the most unstable and are awarded 3 points for morphology. Distraction receives 2 points, and compression receives 1 point (with an additional +1 if a burst component is present).

Question 95

During an L4-L5 laminectomy for severe spinal stenosis, a 3 mm incidental durotomy occurs ventrally, making primary suture repair technically impossible. Cerebrospinal fluid is observed pooling in the surgical field. Which of the following is the most appropriate next step in intraoperative management?

Explanation

For small, inaccessible ventral dural tears where primary repair is impossible, the standard of care involves applying a dural substitute patch and tissue sealant (fibrin glue), followed by flat bed rest. Placing a deep drain on high vacuum is contraindicated as it will continuously pull cerebrospinal fluid and promote a fistula.

Question 96

A 30-year-old male is brought to the trauma bay after a high-speed motorcycle crash. Lateral cervical radiographs demonstrate a Basion-Dental Interval (BDI) of 14 mm. He is intubated and sedated. What is the most appropriate definitive management?

Explanation

A Basion-Dental Interval (BDI) > 12 mm is diagnostic of occipitocervical dissociation, representing highly unstable craniocervical ligamentous disruption. Definitive treatment requires rigid occipitocervical fusion, as orthoses cannot maintain alignment and isolated C1-C2 fusion does not address the occipitocervical instability.

Question 97

A 45-year-old male undergoes an Anterior Lumbar Interbody Fusion (ALIF) at L5-S1 for severe degenerative disc disease. Postoperatively, he complains of cloudy urine and notes infertility issues. Iatrogenic injury to which of the following structures is most likely responsible for his symptoms?

Explanation

Retrograde ejaculation is a known complication of L5-S1 ALIF due to injury to the superior hypogastric plexus, which carries essential sympathetic fibers. Utilizing blunt dissection and avoiding monopolar electrocautery anterior to the L5-S1 disc space significantly minimizes this risk.

Question 98

A 28-year-old female sustains a burst fracture of the C1 ring (Jefferson fracture) after a shallow water diving accident. An AP open-mouth odontoid radiograph reveals lateral displacement of the C1 lateral masses relative to the C2 articular facets. According to the Rule of Spence, a combined overhang greater than what value strongly suggests a transverse ligament rupture?

Explanation

The Rule of Spence dictates that a combined lateral overhang of the C1 lateral masses on C2 of > 6.9 mm on an AP open-mouth radiograph indicates a rupture of the transverse ligament. This implies a highly unstable injury pattern that often requires surgical stabilization.

Question 99

A 42-year-old female presents to the emergency department with acute severe lower back pain, bilateral sciatica, and perineal numbness. Her post-void residual bladder volume is 450 mL. MRI demonstrates a massive L4-L5 central disc extrusion compressing the cauda equina. Current literature suggests that surgical decompression should ideally be performed within what timeframe from symptom onset to maximize full neurologic recovery?

Explanation

Cauda equina syndrome is a surgical emergency. The established literature consensus indicates that surgical decompression performed within 48 hours of symptom onset (specifically bladder dysfunction) provides the optimal chance for significant neurologic and urologic recovery.

Question 100

A 32-year-old male sustains a severe flexion-distraction injury to the cervical spine resulting in a bilateral facet dislocation at C5-C6 and an incomplete spinal cord injury. Which of the following vascular injuries has the highest incidence in this specific trauma pattern and warrants screening?

Explanation

Vertebral artery injuries are highly associated with cervical spine trauma, specifically in flexion-distraction injuries like facet dislocations or fractures involving the foramen transversarium. Preoperative screening with CTA or MRA is highly recommended as undiagnosed occlusion or dissection can alter surgical planning.

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

ABOS Orthopedic Spine MCQs (Set 2): Degenerative Lumbar & Cervical Trauma | 2026 Board Review

Key Takeaway

ABOS Orthopedic Spine MCQs (Set 2): Degenerative Lumbar & Cervical Trauma | 2026 Board Review

Chapter Index