AAOS & ABOS Spine Surgery MCQs: Vertebral Fractures

Question 1

Figures 29a and 29b show the AP and lateral radiographs of a 30-year-old man who has increasingly worse back pain and stiffness. Examination shows painful, limited spinal range of motion. There is no neurologic deficit. What laboratory study would be most helpful in confirming the diagnosis?

Explanation

The radiographs show ankylosing spondylitis with sclerosis of the sacroiliac joints and a "bamboo spine" in the lumbar region. HLA-B27 is positive in 80% to 90% of patients with ankylosing spondylitis and in about 8% of the general population. The findings do not represent diffuse idiopathic skeletal hyperostosis (DISH), which is a radiographic diagnosis in which there are three consecutive levels of nonmarginated osteophytes without disk degeneration. Calin A: Ankylosing spondylitis. Clin Rheum Dis 1985;11:41-60. Booth R, Simpson J, Herkowitz H: Arthritis of the spine, in Herkowitz HH (ed): The Spine, ed 4. Philadelphia, PA, WB Saunders, 1992, p 431.

Question 2

A 29-year-old man undergoes surgery for a grade I isthmic spondylolisthesis at L5. Following surgery, what type of brace will best immobilize the L5-S1 motion segment?

Explanation

The thoracolumbosacral orthosis with thigh extension best immobilizes the lumbosacral junction. Fidler and Plasmans have demonstrated increased motion at the lumbosacral junction with the standard chairback-type brace. Connolly PJ, Grob D: Bracing of patients after fusion for degenerative problems of the lumbar spine: Yes or no? Spine 1998;23:1426-1428.

Question 3

When examining a patient with marked hyperreflexia, which of the following findings best suggests that the condition is not caused by a cerivcal spine pathology?

Explanation

A positive jaw jerk reflex suggests that the problem is above the level of the pons. All of the other physical signs are exhibited in patients with cervical myelopathy. Although these signs also may be present in conditions affecting the brain, they do not help differentiate between a brain etiology and a cervical spine etiology. A jaw jerk reflex, however, is not present in patients with cervical myelopathy alone. Montgomery DM, Brower RS: Cervical spondylotic myelopathy: Clinical syndrome and natural history. Orthop Clin North Am 1992;23:487-493. Ono K, Ebara S, Fuji T, Yonenobu K, Fujiwara K, Yamashita K: Myelopathy hand: New clinical signs of cervical cord damage. J Bone Joint Surg Br 1987;69:215-219.

Question 4

The artery of Adamkiewicz (arteria radicularis, arteria magna) is most commonly found on the

Explanation

Approximately 75% of people have the artery on the left side between T9 and T11. Its relevance to iatrogenic spinal cord problems is still uncertain. Stambaugh J, Simeone F: Vascular complication in spine surgery, in Herkowitz HH (ed): The Spine, ed 4. Philadelphia, PA, WB Saunders, 1992, p 1715.

Question 5

A 62-year-old man with a long history of ankylosing spondylitis has neck pain after lightly bumping his head on the wall. Examination reveals neck pain with any attempted motion; the neurologic examination is normal. Plain radiographs show extensive ankylosis of the cervical spine and kyphosis but no fracture. What is the next most appropriate step in management?

Explanation

A high level of suspicion must be given for a fracture in any patient with ankylosing spondylitis who reports neck pain, even with minimal or no trauma. The neck should be immobilized in its normal position, which is often kyphotic, and plain radiographs should be obtained. If no obvious fracture is seen, CT with reconstruction should be obtained. The placement of in-line traction can have catastrophic effects because it may malalign the spine. Brigham CD: Ankylosing spondylitis and seronegative spondyloarthropathies, in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, pp 724-727.

Question 6

A young man sustains a lumbar strain in an on-the-job motor vehicle accident. Both he and his treating physician feel that he is capable of limited duty with appropriate restrictions shortly after the injury. What term best describes his work status?

Explanation

Because the man is only recently removed from his injury and is judged capable of returning to work with some restrictions, the term that best describes his work status is temporary partial disability.

Question 7

Based on the findings seen at C5-6 in Figure 30, the most likely deficit for this patient will be weakness of the

Explanation

A herniated cervical disk at C5-6 causes a C6 radiculopathy. There are eight cervical nerve roots and seven cervical vertebrae, and C8 exits between the C7 and T1 vertebrae. The C6 nerve root typically innervates the biceps and wrist extensor. The deltoid is predominantly innervated by C5. The wrist flexor and triceps are predominantly innervated by C7. Grip strength is predominantly a function of C8.

Question 8

A 40-year-old woman with no history of back problems has a symptomatic L4-5 disk herniation with an L5 radiculopathy that has failed to respond to 12 weeks of nonsurgical management. In the preoperative discussion, the surgeon advises the patient that the chance of recurrence of the herniation after successful diskectomy is what percent?

Explanation

The incidence of recurrent disk herniation after a successful diskectomy is approximately 5% to 10%. Indications for surgical diskectomy for a recurrence are the same as for a primary diskectomy. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 685-698.

Question 9

In the normal adult, the distance between the basion and the tip of the dens with the head in neutral position is how many millimeters?

Explanation

In the normal adult, the distance between the basion and the tip of the dens is 4 mm to 5 mm. Any distance greater than 5 mm is considered abnormal. This is one way to detect occipitocervical dissociation other than using the Power's ratio, which relies on an anterior dislocation. Wiesel SW, Rothman RH: Occipitoatlantal hypermobility. Spine 1979;4:187-191.

Question 10

The postoperative neurologic prognosis of a patient who has a tumor that is compressing the spinal cord and causing a neurologic deficit depends primarily on the

Explanation

The tumor biology, location, and pretreatment neurologic status are the best predictors of a patient's postoperative neurologic prognosis. Between 60% to 90% of patients who are ambulatory at the time of diagnosis will retain this ability after treatment. Location is important in that less space is available for the cord in the thoracic spine. Lesions located in vascular watershed regions may disrupt the vascular supply of the cord. Weinstein JN: Differential diagnosis and surgical treatment of primary benign and malignant neoplasms, in Frymoyer JW (ed): The Adult Spine: Principles and Practice. New York, NY, Raven Press, 1991, vol 1, pp 829-860.

Question 11

An otherwise healthy 32-year-old man who underwent an uneventful L5-S1 lumbar microdiskectomy 6 weeks ago now reports increasing and severe back pain that awakens him from sleep. Examination reveals a benign-appearing wound, and the neurologic examination is normal. Laboratory studies show an erythrocyte sedimentation rate (ESR) of 90 mm/h and a WBC of 9,000/mm3. Plain radiographs are normal. What is the next most appropriate step in management?

Explanation

The patient's history and laboratory studies are very suspicious for a postoperative diskitis. The predominant symptom often is back pain. An ESR of 90 mm/h is considered significantly elevated and normally would be expected to return to near baseline by 2 weeks postoperatively. A normal WBC result is not unusual with postoperative diskitis. Management should consist of an MRI with gadolinium to confirm the diagnosis, followed by a biopsy percutaneously to obtain tissues for pathology and microbiology. Surgical debridement is reserved for patients whose percutaneous biopsy results are negative and a high index of suspicion for diskitis remains, or when management consisting of IV antibiotics, bed rest, and spinal immobilization fails to provide relief. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 257-271.

Question 12

An 81-year-old man with severe low back pain reports right extensor hallucis longus and anterior tibialis weakness and difficulty urinating over the past 24 hours. He has a temperature of 101 degrees F (38.3 degrees C). MRI scans are shown in Figures 31a and 31b. Management should consist of

Explanation

An epidural abscess with neurologic deficit represents a medical and surgical emergency. The prognosis is related to the timeliness of diagnosis and treatment. Once identified, the primary treatment is surgical decompression of the abscess, followed by organism-specific antibiotics. In the absence of a significant anterior process such as diskitis or vertebral osteomyelitis, lumbar epidural abscesses generally can be drained through a posterior approach. Delayed stabilization usually is not required unless, in the course of decompression, removal of too much of the facets creates an instability; this is an uncommon occurrence. Garfin SR, Vaccaro AR (eds): Orthopaedic Knowledge Update: Spine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 257-271.

Question 13

A 25-year-old man has chronic back pain that has been slowly worsening. He has no constitutional symptoms, and he denies any previous medical problems. Examination shows a tall lean build with no objective neurologic findings or skin lesions. Figure 32 shows a T2-weighted sagittal MRI scan. What is the most likely diagnosis?

Explanation

The MRI scan shows significant dural ectasia, which is seen in more than 60% of patients with Marfan syndrome. It is also relatively common in patients with neurofibromatosis, but this patient has no skin lesions. It has also been described in Ehlers-Danlos syndrome but is less common. Ahn NU, Sponseller PD, Ahn UM, Nallamshetty L, Kuszyk BS, Zinreich SJ: Dural ectasia is associated with back pain in Marfan' syndrome. Spine 2000;25:1562-1568.

Question 14

Which of the following factors has the most effect on the pullout strength of lumbar transpedicular screw fixation?

Explanation

Although all of the factors listed contribute to the pullout strength of transpedicular screw fixation, low bone density generally is felt to be the most influential. Wittenberg RH, Shea M, Swartz DE, Lee KS, White AA III, Hayes WC: Importance of bone mineral density in instrumented spine fusions. Spine 1991;16:647-652.

Question 15

Examination of a 34-year-old man who has had left leg pain for the past 6 weeks reveals minimal weakness of the left extensor hallucis longus and normal ankle jerk and patellar reflexes. Figure 33 shows an axial MRI scan of the L4-5 disk. Based on these findings, the MRI scan results are consistent with compression of the

Explanation

The patient has an L5 radiculopathy secondary to an L4-5 disk herniation that is compressing the traversing L5 nerve root.

Question 16

A 20-year-old college athlete is seen for follow-up after sustaining an injury at football practice 2 days ago. He reports that he tackled a player and felt neck pain and numbness in both arms. The numbness resolved within seconds, but his neck remains painful and stiff. He denies any history of neck pain or injury. Examination reveals limited neck motion. The neurologic examination and radiographs are normal. MRI scans of the cervical spine are shown in Figure 34. During counseling, the patient, his family, and his coach should be informed that he has an acute cervical disk herniation and cannot play

Explanation

A player who has an acute cervical disk herniation should not be allowed to return to play until the acute phase is over. Certain players with large herniations may require surgery before returning to play to eliminate the risk of disk-related stenosis and cord compression. Morganti C, Sweeney CA, Albanese SA, Burak C, Hosea T, Connolly PJ: Return to play after cervical spine injury. Spine 2001;26:1131-1136.

Question 17

An Asian 45-year-old man has bilateral upper extremity dysfunction. Figure 35a shows a T2-weighted sagittal MRI scan of the cervical spine, and Figure 35b shows a T2-weighted axial MRI scan at the level of the C3 vertebral body. What is the most likely pathologic process?

Explanation

Although relatively common in people of Asian origin, OPLL has been reported in other races as well. The radiographic appearance can be variable as there are different types described, but some of the discerning characteristics are seen in these images. On the sagittal view, the bone posterior to the vertebral body extends along the entire length of C2 and C3. This is characteristic of OPLL, whereas cervical spondylosis and DISH more commonly are not confluent. Ankylosing spondylitis more commonly extends significantly into the spinal canal, and neurofibromatosis generally does not cause any bony growth. The axial view shows a large, oval bony projection into the spinal canal, a typical finding of OPLL. McAfee PC, Regan JJ, Bohlman HH: Cervical cord compression from ossification of the posterior longitudinal ligament in non-orientals. J Bone Joint Surg Br 1987;69:569-575.

Question 18

A 36-year-old man has a moderate-sized left paracentral L5-S1 disk herniation with compression of the S1 nerve. Examination will most likely reveal sensory changes at what location?

Explanation

Because the left paracentral L5-S1 disk herniation is compressing the left S1 nerve root, the patient will have numbness along the lateral border and plantar surface of the foot. Numbness along the anterior thigh stopping at the knee is consistent with an L3 radiculopathy. Sensory changes at the dorsum of the foot and great toe normally signify an L5 distribution; the medial leg signifies an L4 distribution. Perianal numbness involves the S2-S5 nerve roots. Wisneski RJ, Garfin SR, Rothman RH, Lutz GE: Lumbar disk disease, in Herkowitz HN, Garfin SR, Balderston RA, Eismont FJ, Bell GR, Wiesel SW (eds): Rothman and Simeone The Spine, ed 4. Philadelphia, PA, WB Saunders, 1999, vol 1, pp 629-634.

Question 19

In a patient with a C5-6 herniation, the most likely sensory deficit will be in the

Explanation

A C5-6 herniation compresses the C6 root, which innervates the radial forearm, thumb, and index finger. The lateral shoulder is innervated by C5. The dorsal forearm and the middle finger typically are innervated by C7. The ulnar forearm, ring finger, and little finger are innervated by C8. There is no specific nerve associated with the volar forearm and palm.

Question 20

A 78-year-old woman has had activity-limiting cervical pain and occipital headaches for the past 4 years. Management consisting of injections, analgesics, and part-time collar wear has provided temporary relief. Examination reveals that her neck pain seems to be primarily located immediately below the skull and is aggravated by long periods of sitting and rotation of her head. Plain radiographs are shown in Figures 36a through 36c. What is the best course of action?

Explanation

Posterior atlantoaxial arthrodesis predictably relieves pain associated with arthrosis of the atlantoaxial joints. Typically, these patients have pain at the base of the occiput and in the most cephalad portion of the posterior aspect of the neck. Associated headache is common and often severe. Pain is aggravated by rotation but usually not by flexion and extension. Diagnostic blocks of the C1-C2 joint and the greater occipital nerve may be helpful to confirm the diagnosis preoperatively. Ghanayem AJ, Leventhal M, Bohlman HH: Osteoarthrosis of the atlanto-axial joints: Long-term follow-up after treatment with arthrodesis. J Bone Joint Surg Am 1996;78:1300-1307.

Question 21

Contraindications to cervical laminectomy as a treatment for cervical spondylotic myelopathy include which of the following findings?

Explanation

Cervical laminectomy is an accepted treatment for multilevel cervical spondylotic myelopathy. When the compression is posterior, laminectomy addresses it directly; when the compression is anterior, it is addressed indirectly (the spinal cord floats posteriorly away from the anterior compression). Preexisting kyphosis is a contraindication to laminectomy because the cord is unable to float posteriorly away from the anterior compression, and the risk for increasing kyphosis is significant. Kyphosis after laminectomy is more likely to develop in younger patients who have fewer degenerative changes to stabilize the spine. Malone DG, Benzyl EC: Laminotomy and laminectomy for spinal stenosis causing radiculopathy or myelopathy, in Clark CR (ed.): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, pp 817-825.

Question 22

What arterial vessel is most prone to injury during posterior iliac crest bone graft harvest?

Explanation

The superior gluteal artery is most at risk with a posterior iliac crest bone graft harvest. The artery leaves the pelvis through the sciatic notch and can be injured by retractors or other sharp instruments entering the sciatic notch area. The deep circumflex iliac, iliolumbar, and fourth lumbar arteries supply the iliacus and iliopsoas muscles and can be damaged during anterior bone graft harvest. The ascending branch of the lateral femoral circumflex artery is at risk during the anterior approach to the hip. Guyer RD, Delmarter RB, Fulp T, Small SD: Complications of cervical spine surgery, in Herkowitz HN, Garfin SR, Balderston RA, Eismont FJ, Bell GR, Wiesel SW (eds): Rothman-Simeone The Spine, ed 4. Philadelphia, PA, WB Saunders, 1999, p 547. Kurz LT, Garfin SR, Booth RE Jr: Iliac bone grafting: Techniques and complications of harvesting, in Garfin SR (ed): Complications of Spine Surgery. Baltimore, MD, Williams and Wilkins, 1989, pp 330-331.

Question 23

A 30-year-old man who underwent an anterior lumbar diskectomy and fusion at L4-5 and L5-S1 through an anterior retroperitoneal approach 1 month ago now reports he is unable to obtain and maintain an erection. The most likely cause of this condition is

Explanation

Sexual dysfunction is a common condition after extensive anterior lumbar surgical dissection. Erectile dysfunction usually is nonorganic but may be related to parasympathetic injury. The parasympathetic nerves are deep in the pelvis at the level of S2-3 and S3-4 and usually are not involved in the surgical field for anterior L4-5 and L5-S1 procedures. Retrograde ejaculation is the result of injury to the sympathetic chain on the anterior surface of the major vessels crossing the L4-5 level and at the L5-S1 interspace. Erectile function and orgasm are not affected by sympathetic injury. The pudendal nerve is primarily a somatic nerve and is not located in the surgical field. Flynn JC, Price CT: Sexual complications of anterior fusion of the lumbar spine. Spine 1984;9:489-492.

Question 24

Which of the following statements about injury of the anterior vascular structures during lumbar disk surgery is true?

Explanation

Vascular injury most commonly occurs at L4-L5, followed by L5-S1 and are associated with use of the pituitary rongeur. Hohf reported that 17 of 58 patients died as a result. Early recognition and treatment of this complication is vital; unfortunately, intraoperative bleeding from the disk space may occur in up to 50% of these patients. Some may be first recognized in the recovery room. Common clinical findings include hypotension, tachycardia, and a rigid abdomen. Formation of an arteriovenous fistula is the most common vascular injury resulting from lumbar disk surgery but is usually not recognized until months after surgery. Cardiomegaly and high output cardiac failure are common presenting symptoms. Hohf RP: Arterial injuries occurring during orthopaedic operations. Clin Orthop 1963;28:21-37. Montorsi W, Ghiringhelli C: Genesis, diagnosis and treatment of vascular complications after intervertebral disk surgery. Int Surg 1973;58:233-235.

Question 25

The photomicrograph in Figure 37 shows a repaired dural tear 4 days after surgery. The material interposed between the dural edges (D) is composed of

Explanation

During the initial healing phases of a dural tear, pia and arachnoid from adjacent nerve roots migrate, fill the dural defect, and create a pia-arachnoid plug. It is this initial plugging of the defect that is believed to prevent further egress of cerebrospinal fluid through the defect. The plug has been shown to develop by the second postoperative day. Fibroblastic proliferation occurs within the dura itself and accounts for the bulbous ends of the dura seen in the photomicrograph. The appearance of the material within the dural edges is inconsistent with the appearance of neural elements, and scar tissue formation occurs later in the healing process. Cain JE Jr, Dryer RF, Barton BR: Evaluation of dural closure techniques: Suture methods, fibrin adhesive sealant, and cyanoacrylate polymer. Spine 1988;13:720-725.

Question 26

When planning surgical correction for adult spinal deformity, the primary goal for regional sagittal alignment is to achieve a Lumbar Lordosis (LL) that is within what range of the Pelvic Incidence (PI)?

Explanation

For optimal sagittal balance in adult spinal deformity, the goal is to achieve a Lumbar Lordosis (LL) within 10 degrees of the patient's Pelvic Incidence (PI). Mismatches greater than 10 degrees are highly correlated with poor health-related quality of life scores.

Question 27

A 55-year-old woman presents with increasing back pain, a forward leaning posture, and fatigue when walking. She underwent a posterior spinal fusion with Harrington rods for adolescent idiopathic scoliosis 35 years ago. Which of the following surgical strategies is most appropriate to restore her sagittal balance?

Explanation

Iatrogenic flatback syndrome is typically rigid and best treated with an asymmetrical, closing wedge osteotomy like a Pedicle Subtraction Osteotomy (PSO). This can provide 30-35 degrees of lordosis at a single level to correct fixed sagittal imbalance.

Question 28

A 24-year-old male is involved in a high-speed motor vehicle collision while wearing only a lap belt. Radiographs and CT show a transverse fracture through the L1 spinous process, pedicles, and vertebral body. Which of the following associated injuries must be highly suspected and ruled out?

Explanation

Chance fractures (flexion-distraction injuries) have a high association (up to 50%) with intra-abdominal injuries. Hollow viscus injuries, particularly bowel perforations, must be actively suspected and ruled out.

Question 29

A 78-year-old female presents with acute, severe mid-back pain after a minor fall. Radiographs show an acute L1 compression fracture with 30% loss of anterior height. Neurologic exam is intact. After 6 weeks of conservative management including bracing and analgesics, she continues to have debilitating pain. What is the most appropriate next step in management?

Explanation

Cement augmentation (kyphoplasty or vertebroplasty) is indicated for symptomatic osteoporotic compression fractures that fail a trial of conservative management (typically 4-6 weeks) and show ongoing marrow edema on MRI.

Question 30

In a 60-year-old patient with adult de novo degenerative lumbar scoliosis, which of the following radiographic findings is most predictive of rapid curve progression?

Explanation

Risk factors for rapid progression in adult degenerative scoliosis include a Cobb angle greater than 30 degrees, apical rotation of Grade II or III, and lateral listhesis greater than 6 mm at any level.

Question 31

According to the Thoracolumbar Injury Classification and Severity (TLICS) score, which of the following combinations automatically meets the threshold (score >= 5) for operative intervention?

Explanation

A burst fracture (2 points) combined with an incomplete neurological deficit (3 points) yields a total TLICS score of 5. A score of 5 or greater favors operative management.

Question 32

A 68-year-old man presents with progressive stooped posture and low back pain. Radiographic analysis reveals a significant mismatch between pelvic incidence and lumbar lordosis. Which of the following compensatory mechanisms allows this patient to maintain horizontal gaze and an upright stance despite a positive sagittal vertical axis?

Explanation

In the setting of positive sagittal imbalance, patients compensate by retroverting the pelvis, which increases Pelvic Tilt (PT). Additional compensatory mechanisms include decreasing thoracic kyphosis and flexing the knees and hips.

Question 33

A 35-year-old man presents after a high-speed MVC. CT imaging demonstrates bilateral pars interarticularis fractures of C2 with 4 mm of anterior translation and 12 degrees of angulation of C2 on C3. The C2-C3 disc space is disrupted. According to the Levine-Edwards classification, what is the most appropriate management?

Explanation

This is a Type II Hangman's fracture, characterized by disruption of the C2-C3 disc with angulation and translation. Initial management involves gentle traction and reduction followed by halo vest immobilization.

Question 34

Which of the following factors is most strongly associated with a high rate of nonunion in conservatively managed Type II odontoid fractures?

Explanation

Risk factors for nonunion of Type II odontoid fractures include initial displacement greater than 5 mm, age over 50 years, posterior displacement, and angulation greater than 10 degrees.

Question 35

A 62-year-old woman undergoes a T10 to Pelvis posterior spinal fusion for adult degenerative scoliosis. One year postoperatively, she presents with palpable hardware prominence and back pain at the upper aspect of her incision. Radiographs show a 20-degree kyphotic angle between T9 and T10. Which of the following intraoperative factors most increases the risk of this complication?

Explanation

Proximal junctional kyphosis (PJK) is heavily influenced by construct selection. Terminating a long fusion construct exactly at the apex of thoracic kyphosis significantly increases the mechanical risk of PJK.

Question 36

In the evaluation of a thoracolumbar burst fracture, disruption of the middle column is the defining characteristic. Which of the following anatomical structures forms the middle column according to the Denis three-column theory?

Explanation

The Denis middle column consists of the posterior half of the vertebral body, the posterior aspect of the annulus fibrosus, and the posterior longitudinal ligament (PLL).

Question 37

A 45-year-old man falls from a roof and sustains an L1 burst fracture with 60% canal compromise and an intact neurologic examination. MRI demonstrates that the posterior ligamentous complex is intact. Which management strategy is most appropriate?

Explanation

Neurologically intact patients with a thoracolumbar burst fracture and an intact posterior ligamentous complex (TLICS score < 4) can be successfully managed nonoperatively with a TLSO. Surgery is generally reserved for neurologic deficits or ligamentous instability.

Question 38

In the evaluation of adult spinal deformity, which of the following radiographic parameters correlates most closely with poor health-related quality of life (HRQOL) scores?

Explanation

A positive Sagittal Vertical Axis (SVA) greater than 5 cm is the radiographic parameter most strongly correlated with adverse health-related quality of life outcomes and pain in adult spinal deformity.

Question 39

A 22-year-old woman involved in a high-speed motor vehicle collision while wearing a lap seatbelt sustains a flexion-distraction injury of T12.

What associated injury must be most highly suspected and ruled out?

Explanation

Chance fractures (flexion-distraction injuries) are highly associated with intra-abdominal injuries. Hollow viscus injuries, such as bowel rupture, occur in up to 50% of these patients.

Question 40

A 35-year-old man presents with bilateral jumped facets at C5-C6 following a diving accident. He has a complete C5 spinal cord injury. Which of the following is the most appropriate next step in management after securing the airway and maintaining hemodynamic stability?

Explanation

In an awake, cooperative patient with a cervical facet dislocation and a neurologic deficit, emergent closed reduction with cranial traction is indicated to decompress the spinal cord as rapidly as possible before obtaining an MRI.

Question 41

When planning surgical correction for a 65-year-old woman with adult degenerative scoliosis, the surgeon aims to restore sagittal balance. The patient has a pelvic incidence of 55 degrees. What is the optimal target lumbar lordosis?

Explanation

To achieve optimal sagittal balance, the lumbar lordosis (LL) should be matched to within 9 degrees of the pelvic incidence (PI). Therefore, a target LL of approximately 55 degrees is appropriate.

Question 42

A 72-year-old woman presents with acute, severe localized mid-back pain after lifting a bag of groceries. Radiographs show a T7 anterior wedge compression fracture. Her neurologic examination is normal. What is the most appropriate initial management?

Explanation

Uncomplicated osteoporotic compression fractures in neurologically intact patients are primarily managed nonoperatively. A brief period of rest, analgesia, bracing, and early mobilization are recommended to prevent severe deconditioning.

Question 43

An 80-year-old man sustains a Type II odontoid fracture after a ground-level fall. Displacement is 2 mm. He has severe medical comorbidities. What is the most appropriate management?

Explanation

In elderly patients with significant comorbidities and minimally displaced Type II odontoid fractures, rigid cervical collar immobilization is preferred. Halo vests carry an unacceptably high morbidity and mortality rate in this population.

Question 44

A 55-year-old man who underwent previous Harrington rod instrumentation for adolescent idiopathic scoliosis now presents with forward-leaning posture, back pain, and thigh fatigue.

What is the primary pathophysiologic mechanism for his thigh fatigue?

Explanation

Flatback syndrome results in a loss of lumbar lordosis and a positive sagittal vertical axis. Patients compensate by extending their hips and flexing their knees, leading to rapid quadriceps and hamstring fatigue.

Question 45

A 25-year-old man is brought to the ED after a severe motorcycle crash. He is flaccid and areflexic below the C6 level. Blood pressure is 80/50 mmHg and heart rate is 50 bpm. What is the primary pathophysiologic cause of his hemodynamic status?

Explanation

Neurogenic shock is characterized by hypotension and bradycardia resulting from a loss of sympathetic vascular tone. It is typically seen in complete or high-grade spinal cord injuries above the T6 level.

Question 46

Which of the following factors most significantly increases the risk of proximal junctional kyphosis (PJK) following long posterior spinal fusion for adult spinal deformity?

Explanation

Terminating a long fusion construct at the thoracolumbar junction (T11-L1) is a major risk factor for PJK because it forces the transition zone into a highly mobile and mechanically stressed region.

Question 47

A patient with a C6 spinal cord injury has intact anal sensation but no voluntary anal sphincter contraction. Motor function is grade 0/5 below the C6 level. What is the ASIA Impairment Scale grade?

Explanation

ASIA B indicates a sensory incomplete spinal cord injury. Sensory function (including sacral segments S4-S5) is preserved, but no motor function is preserved more than three levels below the motor level.

Question 48

A 60-year-old man with advanced ankylosing spondylitis presents with new-onset neck pain after a minor fall. Initial plain radiographs of the cervical spine are unremarkable.

What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable, occult spinal fractures even after minor trauma. Advanced imaging (CT or MRI) is mandatory when there is clinical suspicion, as plain radiographs often miss these fractures.

Question 49

A patient sustains a Denis Zone 3 sacral fracture. Which of the following neurologic deficits is most commonly associated with this specific injury pattern?

Explanation

Denis Zone 3 sacral fractures involve the central sacral canal. They carry a high rate (up to 60%) of bowel, bladder, and sexual dysfunction due to direct injury to the central sacral nerve roots.

Question 50

A 32-year-old construction worker complains of posterior neck pain after forcefully shoveling dirt. Radiographs reveal an avulsion fracture of the C7 spinous process. What is the recommended treatment?

Explanation

A Clay Shoveler's fracture is an isolated, stable avulsion fracture of a lower cervical or upper thoracic spinous process. Because it does not compromise spinal stability, it is managed symptomatically.

Question 51

In a 70-year-old patient undergoing multi-level decompression and fusion for adult degenerative scoliosis, which of the following is an accepted indication for extending the fusion to the pelvis?

Explanation

Extending a long fusion to the pelvis in adult deformity is indicated when there is significant L5-S1 pathology, a severe fractional curve causing coronal imbalance at the lumbosacral junction, or previous wide laminectomy at L5-S1.

Question 52

A 50-year-old diabetic man presents with severe, unrelenting back pain and fever. MRI confirms L3-L4 discitis with a small epidural abscess without spinal cord compression. He is neurologically intact.

What is the most appropriate initial management?

Explanation

In a hemodynamically stable, neurologically intact patient with suspected pyogenic discitis/osteomyelitis, an image-guided biopsy should be performed to obtain a precise microbiologic diagnosis before initiating empiric antibiotics.

Question 53

A 65-year-old man with pre-existing cervical spondylosis presents after a hyperextension injury. He has 2/5 motor strength in his upper extremities and 4/5 motor strength in his lower extremities. Sensory exam shows patchy deficits. What is the most likely diagnosis?

Explanation

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

Question 54

A 65-year-old woman presents with severe mechanical back pain and an inability to stand up straight. When evaluating her sagittal spinopelvic alignment, which of the following formulas correctly describes the relationship between pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS)?

Explanation

Pelvic incidence is a fixed morphological parameter defined as the sum of pelvic tilt and sacral slope (PI = PT + SS). It dictates the amount of lumbar lordosis required to maintain global sagittal balance.

Question 55

A 35-year-old man falls from a ladder. Examination reveals intact motor and sensory function. CT shows an L1 burst fracture with 40% canal compromise. MRI reveals an intact posterior ligamentous complex (PLC). What is his Thoracolumbar Injury Classification and Severity (TLICS) score, and the recommended treatment?

Explanation

The TLICS score is 2: 1 point for a burst fracture mechanism, 0 points for intact neurology, and 0 points for an intact PLC. A score of 3 or less is typically treated nonoperatively with a brace or early mobilization.

Question 56

In adult spinal deformity, which of the following radiographic parameters correlates most strongly with poor health-related quality of life (HRQOL) scores?

Explanation

A positive sagittal vertical axis (SVA) greater than 5 cm is the radiographic parameter most highly correlated with adverse health-related quality of life outcomes in adult spinal deformity patients. Restoration of sagittal balance is the primary goal of reconstructive surgery.

Question 57

A 19-year-old woman involved in a high-speed motor vehicle collision wearing only a lap belt sustains a flexion-distraction injury of the L2 vertebra.

Which of the following concomitant injuries must be ruled out with highest priority?

Explanation

Flexion-distraction injuries (Chance fractures) are highly associated with intra-abdominal injuries, particularly to hollow viscous organs like the small bowel. Prompt general surgery evaluation is critical to prevent sepsis and mortality.

Question 58

A 75-year-old woman with severe osteoporosis presents with a 2-week history of severe mechanical thoracic back pain. Radiographs show a T7 compression fracture with 30% loss of height. She is neurologically intact. She has failed bracing and opioid analgesia. What is the most appropriate next step in management?

Explanation

Vertebral augmentation is indicated for osteoporotic compression fractures in patients who have intractable pain failing conservative management. It provides rapid pain relief and facilitates early mobilization, decreasing the risks of prolonged bed rest.

Question 59

A 55-year-old man with iatrogenic flatback syndrome requires surgical correction. The surgeon plans a single-level procedure to achieve approximately 30 to 35 degrees of sagittal correction. Which of the following osteotomies is most appropriate?

Explanation

A pedicle subtraction osteotomy (PSO) is a three-column wedge osteotomy that hinges on the anterior cortex, typically providing about 30 degrees of lordosis at a single level. SPOs provide ~10 degrees per level, while VCRs are reserved for severe, rigid, multi-planar deformities.

Question 60

A patient with severe adult degenerative scoliosis and a profound loss of lumbar lordosis develops a progressive positive sagittal vertical axis.

What are the expected primary compensatory mechanisms utilized by the patient to maintain an upright posture and horizontal gaze?

Explanation

To compensate for a positive sagittal balance (forward pitch), patients will characteristically retrovert the pelvis (increasing pelvic tilt) and flex their knees. This biomechanically shifts the center of gravity posteriorly.

Question 61

A 25-year-old man falls from a roof and sustains a sacral fracture extending medially to the sacral foramina, involving the central spinal canal. According to the Denis classification, what is the most likely neurologic complication associated with this specific injury zone?

Explanation

This describes a Denis Zone III (central) sacral fracture. Zone III fractures carry the highest risk of neurologic injury (up to 60%), typically manifesting as cauda equina syndrome with profound bowel and bladder dysfunction.

Question 62

A 60-year-old man with advanced ankylosing spondylitis presents with acute neck and back pain after a minor fall.

CT imaging reveals a fracture through the C7-T1 disc space. Which of the following represents the most appropriate management?

Explanation

Fractures in ankylosing spondylitis are highly unstable, three-column injuries (often extension-type) due to the rigidly fused spine. They carry a high risk of neurologic decline and typically require long-segment posterior instrumented fusion for adequate stabilization.

Question 63

Which of the following surgical strategies or patient factors most significantly increases the risk of developing proximal junctional kyphosis (PJK) after a long-segment fusion to the pelvis for adult spinal deformity?

Explanation

Low bone mineral density (osteoporosis) is a major independent risk factor for PJK and proximal junctional failure. Over-correction (not under-correction) of sagittal balance also significantly increases PJK risk by shifting excessive mechanical stress to the adjacent segment.

Question 64

A 65-year-old woman presents with severe low back pain and difficulty standing upright. Radiographs reveal adult degenerative scoliosis. Which of the following radiographic parameters correlates most closely with poor health-related quality of life (HRQOL) scores in this patient?

Explanation

In adult spinal deformity, positive sagittal balance (SVA > 5 cm) has been shown to be the most reliable radiographic predictor of poor clinical outcomes and decreased health-related quality of life (HRQOL) scores.

Question 65

A 45-year-old man falls from a height and sustains an L1 burst fracture. Exam shows normal neurologic function. CT shows 40% loss of vertebral height and retropulsion, with an intact posterior ligamentous complex (PLC) confirmed on MRI. What is his Thoracolumbar Injury Classification and Severity (TLICS) score and the recommended treatment?

Explanation

The TLICS score is 2: morphology is burst (2 points), neurology is intact (0 points), and PLC is intact (0 points). A score of less than 4 generally indicates nonoperative management.

Question 66

A 72-year-old woman with osteoporosis presents with an acute T12 compression fracture. She has severe pain refractory to 6 weeks of maximal medical management and bracing.

What is the most appropriate next step in management?

Explanation

Vertebroplasty and kyphoplasty are indicated for symptomatic osteoporotic compression fractures causing severe pain that is refractory to 4-6 weeks of conservative management.

Question 67

A 24-year-old woman is involved in a high-speed motor vehicle collision while wearing a lap belt. She sustains a T12 Chance fracture.

Which of the following associated injuries must be most highly suspected and ruled out?

Explanation

Chance fractures (flexion-distraction injuries) are frequently associated with lap seatbelt use and have a high incidence (up to 40-50%) of concomitant intra-abdominal injuries, particularly hollow viscus ruptures.

Question 68

A 55-year-old woman who underwent a T10 to L5 posterior spinal fusion 10 years ago now complains of progressive forward posture and thigh pain when walking. Her pelvic incidence is 55 degrees and her lumbar lordosis is 25 degrees. What is the primary cause of her symptoms?

Explanation

The patient has a pelvic incidence to lumbar lordosis (PI-LL) mismatch of 30 degrees (normal target is within 10 degrees). Previous lumbar fusions failing to restore lordosis often result in iatrogenic flatback syndrome and compensatory mechanisms.

Question 69

When planning a long posterior spinal fusion to the sacrum for adult degenerative scoliosis, what is the primary biomechanical advantage of adding bilateral iliac screws?

Explanation

Long spinal constructs ending at S1 have a high failure rate due to significant cantilever forces causing S1 screw pullout. Iliac screws provide robust distal fixation anterior to the pivot point, protecting the S1 screws.

Question 70

An 82-year-old man presents with neck pain after a low-energy fall. CT demonstrates a Type II odontoid fracture with 2 mm of posterior displacement.

He has no neurologic deficits and has significant cardiac comorbidities. What is the most appropriate management?

Explanation

In elderly patients with significant comorbidities, rigid cervical collar immobilization is often preferred for Type II odontoid fractures to avoid the high morbidity and mortality associated with surgical intervention and halo vests.

Question 71

A 30-year-old man presents with a unilateral C5-C6 facet dislocation following a diving accident. He is awake, alert, and has a dense C6 radiculopathy but no central spinal cord injury. What is the most appropriate management regarding closed reduction?

Explanation

In an awake, alert patient with a neurological deficit, an MRI should be obtained prior to closed reduction to rule out a compressive disc herniation that could cause spinal cord injury during reduction maneuvers.

Question 72

A 25-year-old man sustains a severe pelvic crush injury. CT reveals a sacral fracture extending through the sacral foramina. According to the Denis classification, what zone is this fracture, and what is the approximate rate of neurologic injury associated with it?

Explanation

Denis Zone II sacral fractures pass through the neural foramina. They are associated with a neurologic injury rate of approximately 28%, most commonly involving the L5 or S1 nerve roots.

Question 73

A 68-year-old woman undergoes a T10-pelvis posterior spinal fusion. Six months postoperatively, radiographs reveal a 15-degree kyphotic angle between T9 and T10.

Which of the following is considered a primary risk factor for developing proximal junctional kyphosis (PJK)?

Explanation

Proximal junctional kyphosis (PJK) is a common complication after long fusions. Risk factors include disruption of the interspinous ligaments at the UIV, significant sagittal overcorrection, and poor bone quality.

Question 74

A 45-year-old man with a long history of ankylosing spondylitis presents to the ED after a minor fall complaining of neck pain. He has no neurologic deficits. Initial plain radiographs of the cervical spine are read as negative.

What is the next best step in management?

Explanation

Patients with ankylosing spondylitis are at high risk for highly unstable, occult spinal fractures even after minor trauma. A CT scan of the spine is mandatory if they present with pain, as plain films are notoriously inadequate.

Question 75

A 40-year-old man is scheduled for an L5-S1 anterior lumbar interbody fusion (ALIF) for isthmic spondylolisthesis. During the approach, which structure is at highest risk of injury leading to retrograde ejaculation?

Explanation

The superior hypogastric plexus lies anterior to the L5-S1 disc space. Injury to these sympathetic fibers during an anterior approach to L5-S1 can result in retrograde ejaculation in males.

Question 76

A 28-year-old man is involved in a high-speed MVC. Imaging reveals a bilateral pars interarticularis fracture of C2 with 4 mm of anterior translation and severe angulation (Levine and Edwards Type IIA).

What is the appropriate management?

Explanation

Type IIA Hangman's fractures feature significant angulation with disruption of the C2-C3 disc. Traction is strictly contraindicated as it will over-distract the unstable disc space; treatment is gentle reduction with extension and compression in a halo.

Question 77

A 35-year-old construction worker presents with lower neck pain after forcefully lifting a heavy load. Plain radiographs show an avulsion fracture of the spinous process of C7.

There are no neurologic deficits. 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. It is mechanically stable and treated symptomatically with relative rest and analgesia.

Question 78

A 60-year-old woman with osteoporosis presents with back pain after a fall. MRI shows an L2 burst fracture with retropulsion but no spinal cord signal change. Which Denis column(s) must be disrupted to classify a fracture as a burst fracture rather than a simple compression fracture?

Explanation

According to the Denis three-column theory, a compression fracture involves only the anterior column, whereas a burst fracture involves failure of both the anterior and middle columns under axial loading.

Question 79

A 45-year-old man falls from a height and sustains a thoracolumbar burst fracture at L1. He is neurologically intact. Radiographs show 20 degrees of kyphosis and 40% loss of vertebral body height. MRI shows an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity Score (TLICS), what is the most appropriate management?

Explanation

The TLICS score for this patient is 2 (burst fracture = 2, neurologically intact = 0, PLC intact = 0). A score of 3 or less implies nonoperative management is indicated, typically with a TLSO or hyperextension brace.

Question 80

In the evaluation of adult spinal deformity, which of the following spinopelvic parameters is considered a fixed, position-independent morphologic measurement?

Explanation

Pelvic incidence is a fixed anatomic parameter defined by the angle between a perpendicular line to the sacral plate and a line connecting the midpoint of the sacral plate to the bicoxofemoral axis. Unlike pelvic tilt and sacral slope, it does not change with patient positioning.

Question 81

A 65-year-old woman presents with adult degenerative scoliosis and severe mechanical back pain. Preoperative assessment reveals a Pelvic Incidence (PI) of 55 degrees. To optimize her postoperative sagittal alignment and minimize the risk of disability, what should be her target postoperative Lumbar Lordosis (LL)?

Explanation

To achieve optimal sagittal balance in adult spinal deformity, the lumbar lordosis (LL) should be restored to within 9 to 10 degrees of the patient's pelvic incidence (PI). Since her PI is 55 degrees, a target LL of approximately 55 degrees minimizes the PI-LL mismatch.

Question 82

A 22-year-old man involved in a high-speed motor vehicle collision sustains a flexion-distraction injury (Chance fracture) of L2. Which of the following associated injuries must be highly suspected and ruled out?

Explanation

Chance fractures are flexion-distraction injuries commonly caused by lap seatbelts during motor vehicle accidents. They are highly associated with intra-abdominal injuries, particularly to hollow organs such as the bowel, occurring in up to 50% of cases.

Question 83

A 75-year-old man with a history of long-standing ankylosing spondylitis presents with new-onset neck pain after a minor ground-level fall. Neurologic examination is unremarkable. Initial plain radiographs show marked deformity but no obvious fracture. What is the next most appropriate step in management?

Explanation

Patients with ankylosing spondylitis are at a high risk for highly unstable extension-type spinal fractures, even following minor trauma. Due to altered biomechanics, plain films are often inadequate; a CT or MRI must be obtained to definitively rule out an occult fracture or epidural hematoma.

Question 84

A 30-year-old construction worker falls off a ladder and sustains an L1 burst fracture. CT scan reveals a vertically oriented fracture of the lamina. What is the most critical implication of this specific posterior element fracture pattern?

Explanation

A vertical laminar fracture associated with a thoracolumbar burst fracture is highly predictive of a dural tear. During surgery, care must be taken to avoid over-distraction, which could lead to nerve roots being pulled into the fracture site and entrapped.

Question 85

A 68-year-old woman with a history of adult degenerative scoliosis presents with a progressive forward-leaning posture. Radiographs show a Sagittal Vertical Axis (SVA) of +12 cm. What is the primary compensatory mechanism utilizing the pelvis to maintain upright posture in this condition?

Explanation

In the setting of positive sagittal imbalance, the body compensates to maintain an upright gaze. The primary pelvic compensatory mechanism is pelvic retroversion, which corresponds to an increased pelvic tilt (PT) and a decreased sacral slope (SS).

Question 86

A 42-year-old woman undergoes revision spine surgery for flatback syndrome secondary to previous Harrington rod instrumentation. A pedicle subtraction osteotomy (PSO) is planned at L3. Approximately how many degrees of sagittal correction can typically be expected from a single-level lumbar PSO?

Explanation

A pedicle subtraction osteotomy (PSO) is a closing wedge osteotomy through the posterior elements and vertebral body that hinges on the anterior cortex. It typically provides approximately 30 to 35 degrees of lordotic correction per level.

Question 87

A patient is evaluated for adult spinal deformity. Radiographic parameters reveal a Pelvic Incidence (PI) of 60 degrees, a Pelvic Tilt (PT) of 30 degrees, and a Sacral Slope (SS) of 30 degrees. Which of the following statements best describes the relationship of these spinopelvic parameters?

Explanation

Pelvic incidence (PI) is a fixed morphologic parameter representing the algebraic sum of the pelvic tilt (PT) and sacral slope (SS). The equation PI = PT + SS is fundamental in understanding spinopelvic alignment and calculating deformity correction targets.

Question 88

A 45-year-old construction worker falls from a height of 15 feet and complains of severe back pain.

Radiographs and a CT scan reveal an L1 burst fracture. Which of the following radiographic findings is most specifically indicative of a concomitant posterior ligamentous complex (PLC) injury, thereby increasing the indication for operative stabilization?

Explanation

Widening of the interspinous distance on an AP radiograph indicates severe flexion-distraction forces and disruption of the posterior ligamentous complex (PLC). PLC disruption implies significant mechanical instability in a burst fracture, serving as a strong indication for surgical stabilization.

Question 89

In surgical planning for a 65-year-old woman with adult degenerative scoliosis and severe sagittal imbalance, restoring physiological alignment is critical to minimize mechanical failure. Which of the following best represents the ideal relationship between pelvic incidence (PI) and lumbar lordosis (LL) for optimal postoperative sagittal balance?

Explanation

Optimal sagittal balance in adult spinal deformity surgery is achieved when Lumbar Lordosis (LL) is restored to within 10 degrees of the Pelvic Incidence (PI). Pelvic Incidence is a fixed morphological parameter that cannot be changed surgically, necessitating the appropriate correction of LL to match it.

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

AAOS & ABOS Spine Surgery MCQs (Set 4): Vertebral Fractures & Adult Deformity | 2000 Board Review

Key Takeaway

AAOS & ABOS Spine Surgery MCQs (Set 4): Vertebral Fractures & Adult Deformity | 2000 Board Review

Chapter Index