Orthopedic Spine MCQs 2026 | Board Review & Answers

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

29b 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

31b 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

35b 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

36b 36c 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

A patient with signs of myelopathy exhibits a hyperactive jaw jerk reflex on physical examination. Which of the following best describes the most likely anatomic location of the primary pathology?

Explanation

The jaw jerk reflex is mediated by the trigeminal nerve. A hyperreflexic jaw jerk indicates an upper motor neuron lesion above the level of the pons, successfully distinguishing intracranial pathology from cervical myelopathy.

Question 27

A 60-year-old woman with long-standing rheumatoid arthritis presents with progressive neck pain and subjective hand clumsiness. Flexion-extension radiographs reveal an atlantodental interval (ADI) of 11 mm. What is the most appropriate management?

Explanation

In patients with rheumatoid arthritis, an ADI greater than 9 mm or the presence of myelopathy are strong indications for surgical stabilization. Posterior C1-C2 fusion is the preferred treatment for atlantoaxial instability without significant basilar invagination.

Question 28

A 24-year-old man is involved in a motor vehicle accident and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). Imaging shows severe angulation with minimal translation, and flexion-extension views demonstrate an opening of the posterior C2-C3 disc space (Type IIA). Which of the following treatments is strictly contraindicated?

Explanation

Type IIA Hangman's fractures involve severe angulation and an incompetent posterior longitudinal ligament. Cervical traction is strictly contraindicated as it may cause massive over-distraction and subsequent catastrophic neurological injury.

Question 29

A 45-year-old man presents with sharp radicular pain radiating down the posterior aspect of his right leg to the lateral border of his foot. On examination, he exhibits an absent Achilles reflex and weakness in plantar flexion. Which nerve root is most likely compressed?

Explanation

S1 radiculopathy typically presents with pain in the posterior leg and lateral foot, weakness in ankle plantar flexion, and a diminished or absent Achilles reflex. This is most commonly caused by a paracentral disc herniation at the L5-S1 level.

Question 30

A 65-year-old man with underlying cervical spondylosis falls forward and strikes his chin, sustaining a hyperextension injury. He immediately develops profound weakness in his upper extremities with relatively preserved motor function in his lower extremities. What is the most likely diagnosis?

Explanation

Central cord syndrome classically occurs in older patients with pre-existing cervical spondylosis following a hyperextension injury. It disproportionately affects the medially located cervical motor tracts, causing upper extremity weakness greater than lower extremity weakness.

Question 31

A 55-year-old man with a long-standing history of ankylosing spondylitis sustains a minor ground-level fall. He complains of severe lower cervical neck pain, but initial plain radiographs in the emergency department are read as normal. What is the next best step in management?

Explanation

Patients with ankylosing spondylitis have rigidly fused, osteopenic spines and are at exceptionally high risk for unstable, occult fractures even after minor trauma. A CT scan of the entire cervical spine is mandatory when plain radiographs are negative or inadequate.

Question 32

A 60-year-old man undergoes a C3-C6 posterior cervical laminectomy and fusion for cervical spondylotic myelopathy. On postoperative day 2, he develops profound new weakness in right shoulder abduction and elbow flexion, but has no new sensory deficits or leg symptoms. What is the most likely etiology?

Explanation

C5 nerve root palsy is a recognized complication following cervical decompression, particularly via posterior approaches. It is generally attributed to the posterior shifting of the spinal cord (tethering effect) or reperfusion injury, typically presenting as isolated deltoid and biceps weakness.

Question 33

A 15-year-old female gymnast presents with chronic, insidious-onset low back pain that significantly worsens with spinal extension. Her neurologic examination is normal. Plain radiographs show a bilateral radiolucent line across the pars interarticularis of L5. What is the most appropriate initial management?

Explanation

Spondylolysis (pars interarticularis defect) in adolescent athletes is typically managed conservatively. Initial treatment consists of rest from the offending activity and often an antilordotic (TLSO) brace to reduce stress and allow the fracture to heal.

Question 34

A 35-year-old woman is involved in a high-speed collision. CT of the thoracolumbar spine demonstrates an L1 burst fracture with a fracture of the posterior elements.

Her neurologic examination is normal. The TLICS score is calculated as 5 (Morphology=2; PLC=3; Neuro=0). What is the recommended management?

Explanation

The Thoracolumbar Injury Classification and Severity (TLICS) score dictates treatment pathways. A score of 5 or greater indicates an unstable injury pattern that mandates surgical stabilization.

Question 35

In the surgical evaluation and reconstruction of adult degenerative scoliosis, achieving proper sagittal balance is highly correlated with improved clinical outcomes. Which of the following spinopelvic parameters is the primary target?

Explanation

Restoration of optimal sagittal balance is critical in adult spinal deformity surgery. A PI-LL mismatch of less than 10 degrees is the widely accepted target to minimize postoperative disability and prevent implant failure.

Question 36

A 22-year-old man is a restrained backseat passenger (lap belt only) in a motor vehicle collision. He sustains a flexion-distraction injury to his lumbar spine (Chance fracture). Which associated injury must be most actively excluded during his trauma workup?

Explanation

Chance fractures (flexion-distraction injuries) are classically associated with lap-belt use and carry a very high incidence (up to 50%) of concomitant intra-abdominal injuries, particularly hollow viscus (bowel) perforations.

Question 37

A 62-year-old man with poorly controlled diabetes presents with severe, unrelenting back pain and low-grade fevers. MRI with contrast reveals increased T2 signal in the L3-L4 intervertebral disc and adjacent vertebral endplates with enhancement. What is the most common causative organism?

Explanation

Pyogenic spondylodiscitis is most commonly caused by Staphylococcus aureus. Diagnosis should be confirmed with blood cultures or a CT-guided needle biopsy prior to initiating long-term intravenous antibiotics.

Question 38

A 16-year-old boy presents with progressive rounding of his upper back and mild pain after prolonged sitting. Lateral radiographs show a rigid thoracic kyphosis of 55 degrees. Which of the following radiographic findings definitively meets the Sorensen criteria for Scheuermann's disease?

Explanation

Scheuermann's kyphosis is defined radiographically by the Sorensen criteria, which require a regional kyphosis >40 degrees and anterior wedging of >5 degrees in at least three consecutive vertebrae.

Question 39

A 40-year-old man presents to the emergency department with severe low back pain, bilateral leg weakness, and numbness in his perineal region. He reports he has not urinated in 14 hours. A bedside bladder ultrasound shows a post-void residual (PVR) volume of 600 mL. What is the most appropriate next step?

Explanation

The patient exhibits classic signs of cauda equina syndrome (CES), including saddle anesthesia and profound urinary retention (PVR > 300 mL is highly specific). Urgent MRI is required to confirm the level of compression prior to emergency surgical decompression.

Question 40

A 75-year-old woman sustains a Type II odontoid fracture after a ground-level fall. Which of the following factors is most strongly associated with a high rate of nonunion if managed nonoperatively with a halo vest?

Explanation

Risk factors for nonunion of Type II odontoid fractures include age > 50 years, displacement > 5 mm, posterior displacement, and a fracture gap > 1 mm. High-risk patients often require primary surgical stabilization.

Question 41

A 68-year-old man complains of bilateral calf and thigh pain that occurs after walking two blocks. The pain is rapidly relieved when he leans forward on a shopping cart or sits down. Standing perfectly upright exacerbates the pain. His pedal pulses are strongly palpable. What is the most likely diagnosis?

Explanation

Neurogenic claudication secondary to lumbar spinal stenosis is classically exacerbated by lumbar extension (standing upright) and relieved by lumbar flexion (sitting, leaning on a cart), which increases the cross-sectional area of the spinal canal.

Question 42

A 30-year-old woman is brought to the trauma bay after a rollover motor vehicle collision. She is fully awake, alert, and neurologically intact. Cervical spine CT demonstrates a left-sided unilateral facet dislocation at C5-C6. What is the most appropriate next step in management?

Explanation

In an awake, alert, and cooperative patient without neurologic deficit, urgent closed reduction via cranial traction is recommended. A pre-reduction MRI is generally reserved for patients who are uncooperative, comatose, or who fail closed reduction.

Question 43

A 45-year-old man presents with right arm pain radiating to the lateral forearm and thumb. He has weakness in wrist extension and a diminished brachioradialis reflex. Which of the following nerve roots is most likely affected?

Explanation

A C6 radiculopathy classically presents with pain radiating to the lateral forearm and thumb, weakness in wrist extension and elbow flexion, and a diminished brachioradialis reflex.

Question 44

A 25-year-old man is involved in a motor vehicle collision. Imaging reveals a fracture through the pars interarticularis of C2 bilaterally with 2 mm of displacement and no angulation. According to the Levine and Edwards classification, what is the most appropriate management?

Explanation

This is a Type I traumatic spondylolisthesis of the axis (Hangman's fracture), characterized by less than 3 mm of displacement and no angulation. It is highly stable and best managed non-operatively with a rigid cervical collar.

Question 45

A 70-year-old man with a history of cervical spondylosis falls forward, striking his chin. He presents with profound motor weakness in his upper extremities but is able to move his lower extremities against gravity. He has variable sensory loss and urinary retention. Which of the following is the most likely diagnosis?

Explanation

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

Question 46

A 15-year-old male gymnast complains of worsening lower back pain exacerbated by extension. Oblique radiographs demonstrate a 'collar on the Scotty dog' appearance. Which of the following is the most appropriate initial management?

Explanation

The clinical presentation and radiographic findings are classic for spondylolysis. The mainstay of initial treatment is non-operative, focusing on activity modification, bracing (in some cases), and core strengthening exercises.

Question 47

A 55-year-old man with long-standing ankylosing spondylitis presents to the emergency department after a minor ground-level fall. He complains of severe lower neck pain. Neurological examination is intact. Initial plain radiographs of the cervical spine are difficult to interpret due to patient positioning and underlying deformity. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are at extremely high risk for unstable spinal fractures even after minor trauma. Due to altered anatomy, plain films are often inadequate, making a CT scan of the entire cervical spine mandatory.

Question 48

A 60-year-old woman with a history of multiple myeloma presents with progressively worsening back pain and new-onset lower extremity weakness. MRI demonstrates a T8 vertebral body metastatic lesion with epidural spinal cord compression. She has no mechanical instability. According to the NOMS framework, what is the best initial treatment?

Explanation

Multiple myeloma is highly radiosensitive. In the absence of mechanical instability, the NOMS framework recommends radiation therapy and systemic corticosteroids as the primary treatment for epidural spinal cord compression.

Question 49

A 42-year-old man presents to the emergency department with severe lower back pain, bilateral sciatica, saddle anesthesia, and urinary incontinence. Which of the following is the most critical next step?

Explanation

These classic symptoms represent Cauda Equina Syndrome, a surgical emergency. Urgent MRI is required to confirm the diagnosis, followed immediately by surgical decompression to maximize the chance of neurologic recovery.

Question 50

Which of the following radiographic criteria is definitively diagnostic for Diffuse Idiopathic Skeletal Hyperostosis (DISH)?

Explanation

DISH is characterized by flowing anterolateral ossification of at least four contiguous vertebral bodies, preservation of disc height, and the absence of sacroiliac joint erosion or fusion.

Question 51

During the physical examination of a patient with suspected cervical myelopathy, you perform a rapid flicking of the distal phalanx of the middle finger, which elicits an involuntary flexion of the thumb and index finger. What is the name of this clinical sign?

Explanation

The Hoffmann sign is an upper motor neuron reflex indicative of cervical spinal cord compression (myelopathy). It is elicited by flicking the distal phalanx of the middle finger, resulting in flexion of the thumb and index finger.

Question 52

A 75-year-old woman presents with a displaced Type II odontoid fracture after a fall. What is the major disadvantage of utilizing a halo vest orthosis in this specific patient population compared to a rigid cervical collar?

Explanation

In the elderly population, halo vest immobilization is associated with a significantly increased risk of major complications, including pneumonia and mortality, compared to a rigid cervical collar. Therefore, rigid collars are generally preferred despite a higher nonunion rate.

Question 53

A 65-year-old man presents with neurogenic claudication characterized by bilateral leg pain and heaviness that worsens with walking and improves when leaning forward over a shopping cart. What is the primary anatomical structure responsible for dorsal central canal narrowing in degenerative lumbar spinal stenosis?

Explanation

In degenerative lumbar spinal stenosis, narrowing of the central canal is primarily caused dorsally by hypertrophy and buckling of the ligamentum flavum, often combined ventrally with disc bulging and laterally with facet arthropathy.

Question 54

A patient suffers a penetrating knife injury to the right side of the spinal cord at the T10 level. Which of the following neurological deficits is expected below the level of the injury?

Explanation

This describes Brown-Séquard syndrome resulting from spinal cord hemisection. It classically presents with ipsilateral loss of motor function and proprioception, and contralateral loss of pain and temperature sensation.

Question 55

A 60-year-old woman with a 20-year history of rheumatoid arthritis presents for preoperative evaluation before a total knee arthroplasty. Flexion-extension radiographs of the cervical spine reveal an anterior atlantodental interval (ADI) of 6 mm. What is the most appropriate next step?

Explanation

An ADI > 3 mm in an adult suggests transverse ligament instability, and > 5 mm implies higher risk. MRI is required to measure the Space Available for the Cord (SAC); a SAC < 14 mm strongly predicts impending neurologic deficit.

Question 56

Which of the following surgical approaches is generally contraindicated for the treatment of a central, calcified thoracic disc herniation causing myelopathy?

Explanation

A posterior laminectomy is contraindicated for central thoracic disc herniations due to the high risk of catastrophic spinal cord injury caused by traction on the cord to access the ventral pathology.

Question 57

A 22-year-old woman is involved in a high-speed motor vehicle collision while wearing a lap belt. She sustains a flexion-distraction injury (Chance fracture) of L1. What concomitant injury must be heavily suspected and evaluated for?

Explanation

Chance fractures are highly associated with seatbelt injuries. There is a very high incidence (up to 50%) of concurrent intra-abdominal hollow viscus injuries, such as bowel or mesenteric lacerations, which must be ruled out.

Question 58

A 55-year-old woman presents with neurogenic claudication and lower back pain. Radiographs reveal a grade 1 degenerative spondylolisthesis at L4-L5. She has failed six months of physical therapy and injections. Which of the following is the most appropriate surgical intervention based on major clinical trials?

Explanation

The SPORT trial demonstrated that surgical decompression combined with instrumented fusion provides superior clinical outcomes compared to laminectomy alone for patients with symptomatic degenerative spondylolisthesis.

Question 59

A 65-year-old man presents with acute bilateral leg pain, urinary retention, and saddle anesthesia. Post-void residual (PVR) ultrasound is 400 mL. Which of the following urodynamic findings is most consistent with the underlying pathophysiology of this syndrome?

Explanation

Cauda equina syndrome causes a lower motor neuron lesion affecting the S2-S4 nerve roots. This results in an areflexic (flaccid) bladder and overflow incontinence, commonly detected by a post-void residual greater than 100-200 mL.

Question 60

A 45-year-old man presents with severe radicular leg pain. MRI demonstrates a far-lateral disc herniation at the L4-L5 level. Which of the following physical examination findings is most likely to be present?

Explanation

A far-lateral disc herniation at L4-L5 compresses the exiting L4 nerve root, unlike a paracentral herniation which affects the traversing L5 root. L4 radiculopathy is characterized by weakness in knee extension, numbness over the medial lower leg, and a depressed patellar reflex.

Question 61

A 72-year-old woman sustains a hyperextension injury to her cervical spine. She presents with significant weakness in her upper extremities, but her lower extremities have 4/5 motor strength. Which function is typically the last to recover in this specific spinal cord syndrome?

Explanation

Central cord syndrome classically presents with upper extremity weakness greater than lower extremity weakness. The typical sequence of neurological recovery is lower extremity function first, followed by bowel/bladder, proximal upper extremity, and finally fine motor function of the hand.

Question 62

A 24-year-old male is involved in a high-speed motor vehicle collision. On presentation, his blood pressure is 80/50 mmHg and heart rate is 50 bpm. His extremities are warm and well-perfused. Which of the following is the primary pathophysiological mechanism for his vital sign abnormalities?

Explanation

The patient is exhibiting neurogenic shock, characterized by hypotension and bradycardia with warm extremities. This results from disruption of descending sympathetic pathways in the cervical or high thoracic spinal cord, leading to unopposed vagal tone.

Question 63

A

14-year-old girl is evaluated for scoliosis. Radiographs reveal a right thoracic curve of 42 degrees. Her Risser stage is 0 and she is premenarchal. What is the most appropriate next step in management?

Explanation

Bracing is indicated for skeletally immature patients (Risser 0-2) with adolescent idiopathic scoliosis who have a curve between 25 and 45 degrees. A TLSO brace worn 18-23 hours a day significantly decreases the risk of curve progression to the surgical threshold.

Question 64

A 55-year-old man presents with progressive gait difficulty and hand clumsiness. Examination reveals hyperreflexia, a positive Hoffman's sign, and difficulty buttoning his shirt. Which of the following tests best differentiates cervical myelopathy from a central nervous system pathology above the foramen magnum?

Explanation

The jaw jerk reflex tests the trigeminal nerve (cranial nerve V). A hyperactive jaw jerk reflex suggests a pathologic upper motor neuron lesion above the foramen magnum, distinguishing cranial pathology from cervical myelopathy.

Question 65

During a posterior approach for a TLIF at L4-L5, a pedicle screw is being placed into the right L4 vertebra. A medial breach of the pedicle wall occurs. Which neural structure is at greatest risk of iatrogenic injury?

Explanation

A medial breach of the lumbar pedicle endangers the traversing nerve root of that same level (the L4 root at the L4 pedicle). An inferior pedicle breach, conversely, risks the exiting nerve root of that level (the L4 exiting root).

Question 66

An 82-year-old man presents with neck pain following a ground-level fall. CT scan reveals a Type II odontoid fracture with 2 mm of displacement. He has a history of severe COPD, congestive heart failure, and diabetes. What is the most appropriate definitive management?

Explanation

While surgical fixation is often favored for Type II odontoid fractures in healthy adults, this patient's severe comorbidities and age make surgery high risk. Halo immobilization is strictly contraindicated in the elderly due to severe respiratory complications, making a rigid collar the safest choice despite nonunion risks.

Question 67

A

35-year-old man is diagnosed with an unstable T12 thoracolumbar burst fracture with MRI-confirmed posterior ligamentous complex (PLC) disruption. He is neurologically intact. Based on the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his point value and the recommended treatment?

Explanation

The TLICS score is 5: burst fracture morphology (2 points), posterior ligamentous complex injury (3 points), and intact neurology (0 points). A score of 5 or higher is a definitive indication for operative management.

Question 68

In a patient with adolescent idiopathic scoliosis, which of the following best describes the structural relationship between the apical vertebra and the rib hump?

Explanation

In adolescent idiopathic scoliosis, the vertebral body rotates toward the convexity of the curve while the spinous processes rotate toward the concavity. This axial rotation pushes the ribs on the convex side posteriorly, creating the classic rib hump seen on the Adams forward bend test.

Question 69

A 16-year-old male gymnast complains of chronic lower back pain. Radiographs show a grade I spondylolisthesis at L5-S1. What radiographic spinopelvic parameter is most strongly correlated with the risk of progression in isthmic spondylolisthesis?

Explanation

Pelvic incidence (PI) is a fixed morphologic parameter determined by the sum of Pelvic Tilt and Sacral Slope. A high pelvic incidence strongly correlates with an increased risk of progression in isthmic spondylolisthesis due to elevated shear forces at the lumbosacral junction.

Question 70

A 50-year-old man presents with severe neck pain radiating down his right arm. Neurologic examination reveals weakness in triceps extension and wrist flexion, along with a diminished triceps reflex. He also has numbness over his middle finger. Which of the following nerve roots is most likely compressed?

Explanation

This classic presentation describes a C7 radiculopathy, which typically causes weakness in the triceps and wrist flexors. It is associated with a diminished triceps reflex and sensory loss in the middle finger.

Question 71

A 78-year-old man with severe chronic obstructive pulmonary disease and congestive heart failure sustains a displaced Type II odontoid fracture after a low-energy fall. He is deemed a high-risk surgical candidate. What is the most appropriate initial management?

Explanation

In elderly patients who are poor surgical candidates, a hard cervical collar is the preferred initial treatment for Type II odontoid fractures. Halo vest immobilization is contraindicated in this demographic due to high rates of morbidity and mortality.

Question 72

A 60-year-old diabetic male presents with worsening back pain, fever, and progressive lower extremity weakness. MRI demonstrates a large ventral epidural abscess spanning L2 to L4 with cord compression. What is the most appropriate definitive surgical management?

Explanation

Ventral epidural abscesses causing neurologic deficits require anterior decompression via corpectomy and debridement. Posterior laminectomy is inadequate for ventral clearance and may cause iatrogenic spinal instability.

Question 73

A 14-year-old gymnast presents with persistent lower back pain exacerbated by extension. Radiographs confirm a Grade 1 isthmic spondylolisthesis at L5-S1. If this patient were to develop a radicular neurologic deficit, which nerve root is most commonly affected?

Explanation

Isthmic spondylolisthesis at L5-S1 typically causes compression of the exiting L5 nerve root in the neural foramen. This is due to the hypertrophic fibrocartilaginous tissue that forms at the pars interarticularis defect.

Question 74

A 65-year-old woman is planning to undergo corrective surgery for a symptomatic adult spinal deformity. Her preoperative radiographs demonstrate a pelvic incidence (PI) of 60 degrees. To achieve optimal spino-pelvic alignment and minimize adjacent segment disease, the target postoperative lumbar lordosis (LL) should be within how many degrees of her PI?

Explanation

The SRS-Schwab adult spinal deformity classification emphasizes that lumbar lordosis (LL) should match pelvic incidence (PI) within 10 degrees (PI-LL < 10 degrees). Achieving this alignment correlates with improved functional outcomes and decreased mechanical complications.

Question 75

A 45-year-old man with ankylosing spondylitis presents after a minor motor vehicle collision. A non-contrast CT shows a highly displaced fracture through the C5-C6 disc space extending through the posterior elements.

Which of the following is the most significant acute risk associated with patient positioning and transport?

Explanation

The ankylosed spine fractures like a long bone, rendering it extremely unstable. Minimal movement or hyperextension during transport can easily cause a catastrophic iatrogenic spinal cord injury or epidural hematoma.

Question 76

A 58-year-old female with breast cancer presents with back pain. MRI shows a lytic metastasis at T8. According to the Spinal Instability Neoplastic Score (SINS), which of the following clinical or radiographic features contributes most strongly to a higher score (indicating instability)?

Explanation

Mechanical pain (pain exacerbated by movement and relieved by recumbency) receives 3 points on the SINS scale and is a primary clinical indicator of impending spinal instability. Osteoblastic lesions and rigid locations score lower.

Question 77

A 70-year-old man with severe cervical spondylosis falls and strikes his chin. He develops bilateral upper extremity weakness that is far worse than his lower extremity weakness. Which spinal tract is predominantly responsible for this disproportionate motor deficit?

Explanation

Central cord syndrome preferentially damages the medial aspect of the lateral corticospinal tracts. Because the motor fibers for the upper extremities are located medially relative to the lower extremity fibers, patients exhibit disproportionate upper extremity weakness.

Question 78

A 62-year-old male presents with severe myelopathy. Imaging reveals dense ossification along the posterior margin of the C3-C6 vertebral bodies, consistent with OPLL.

If an anterior surgical approach (corpectomy) is selected, what is the most common and feared intraoperative complication specific to this pathology?

Explanation

The ossified posterior longitudinal ligament often adheres directly to or incorporates the dura mater. Consequently, anterior resection carries a very high risk of dural tears and subsequent CSF leakage.

Question 79

A 68-year-old man reports bilateral calf pain after walking two blocks. The pain is rapidly relieved when he leans forward on a shopping cart. Which of the following findings most reliably differentiates this neurogenic claudication from vascular claudication?

Explanation

Neurogenic claudication is characteristically relieved by lumbar flexion (e.g., leaning forward, sitting), which increases the cross-sectional area of the spinal canal. Vascular claudication is typically relieved simply by resting or standing still.

Question 80

A 24-year-old man presents after a high-speed motor vehicle collision. Radiographs demonstrate a Type II traumatic spondylolisthesis of the axis (Hangman's fracture).

What is the classic mechanism of injury for the initial pars interarticularis fracture in this scenario?

Explanation

In motor vehicle accidents, the classic mechanism for a Hangman's fracture is hyperextension combined with axial loading. This differs from judicial hanging, which involves hyperextension and massive distraction.

Question 81

A 35-year-old construction worker sustains an L1 fracture with 50% canal compromise and 25 degrees of kyphosis after a fall. Neurologic exam is normal. According to the Thoracolumbar Injury Classification and Severity (TLICS) score, how many points are assigned specifically for the burst morphology of this fracture?

Explanation

Under the TLICS system, fracture morphology is scored as follows: compression = 1 point, burst = 2 points, translation/rotation = 3 points, and distraction = 4 points. Therefore, a burst fracture morphology contributes 2 points.

Question 82

A 42-year-old woman presents with sudden onset severe low back pain, bilateral sciatica, perineal numbness, and difficulty initiating micturition (post-void residual is 350 mL). MRI confirms a massive L4-L5 central disc herniation. What is the most appropriate management?

Explanation

This patient has incomplete cauda equina syndrome (CES-I), which is an absolute surgical emergency. Emergent surgical decompression, ideally within 24 to 48 hours, is required to prevent permanent sphincter dysfunction and paralysis.

Question 83

A 15-year-old boy presents with a progressive thoracic kyphosis of 55 degrees. Imaging is evaluated for Scheuermann's kyphosis.

To meet the classic Sorensen criteria, what is the minimum degree of anterior wedging required in each of three consecutive vertebrae?

Explanation

The Sorensen criteria for diagnosing Scheuermann's disease require anterior wedging of at least 5 degrees in 3 or more consecutive vertebrae. This is accompanied by an overall thoracic kyphosis typically greater than 45 degrees.

Question 84

A 48-year-old woman undergoes a right-sided C5-C6 anterior cervical discectomy and fusion (ACDF). Postoperatively, she exhibits significant hoarseness and a weak voice. Laryngoscopy confirms unilateral vocal cord paralysis. Injury to which of the following structures is responsible?

Explanation

The recurrent laryngeal nerve innervates the majority of the intrinsic muscles of the larynx. Injury to this nerve during an ACDF results in true vocal cord paralysis, manifesting clinically as severe hoarseness and a breathy voice.

Question 85

A 65-year-old man presents with progressive gait clumsiness and deteriorating hand dexterity. Examination reveals a positive Hoffman's sign bilaterally and hyperreflexia in the lower extremities, but diminished biceps reflexes bilaterally. What is the most likely location of the primary pathology?

Explanation

Diminished biceps reflexes represent a lower motor neuron sign at the level of compression, while hyperreflexia below this level represents an upper motor neuron sign. This combination is classic for C5-C6 cervical spondylotic myelopathy.

Question 86

An 82-year-old woman falls and presents with neck pain. The radiograph shows a displaced Type II odontoid fracture. She has significant medical comorbidities (Charlson Comorbidity Index of 6) and no neurologic deficit. What is the most appropriate initial management?

Explanation

In elderly patients with severe medical comorbidities, a rigid cervical collar is the preferred initial treatment for Type II odontoid fractures. This is due to the high morbidity and mortality associated with halo vests and surgical intervention in this specific demographic.

Question 87

A 54-year-old intravenous drug user presents with severe lower back pain, a low-grade fever, and new-onset urinary retention. What is the most sensitive imaging modality and expected elevated laboratory marker to confirm the suspected diagnosis?

Explanation

MRI with gadolinium is the gold standard for diagnosing a spinal epidural abscess. CRP and ESR are highly sensitive inflammatory markers for spinal infections, whereas WBC counts are often falsely normal.

Question 88

A 12-year-old premenarchal female presents with a right thoracic curve measuring 48 degrees on a standing PA radiograph. She is Risser 0 and has a Sanders skeletal maturity stage of 2. What is the most appropriate management?

Explanation

Posterior spinal fusion is indicated for adolescent idiopathic scoliosis curves greater than 45-50 degrees. Highly immature patients (Risser 0, premenarchal) with curves of this magnitude have a near 100% risk of progression and require surgical intervention.

Question 89

A 68-year-old man complains of bilateral calf pain and heaviness that occurs after walking two blocks. Which of the following historical factors is most specific for neurogenic claudication rather than vascular claudication?

Explanation

Pain relief with lumbar flexion (sitting or the "shopping cart sign") increases the spinal canal area and is highly characteristic of neurogenic claudication. Vascular claudication is typically relieved simply by resting in a standing position.

Question 90

A 15-year-old male gymnast presents with mechanical low back pain. Radiographs reveal a Grade 1 slip at L5-S1. What is the anatomic location of the defect causing this specific type of spondylolisthesis?

Explanation

Isthmic spondylolisthesis (Wiltse Type II) is caused by a defect or stress fracture in the pars interarticularis. It is most commonly seen in young athletes who undergo repetitive lumbar hyperextension.

Question 91

A 60-year-old diabetic male undergoes a lumbar microdiscectomy. Three weeks later, he presents with severe, unremitting back pain and elevated inflammatory markers. An MRI shows fluid in the disc space with endplate enhancement. What is the most likely causative organism?

Explanation

Staphylococcus aureus is the most common causative organism for both spontaneous and postoperative pyogenic discitis and vertebral osteomyelitis.

Question 92

A 72-year-old man with known cervical spondylosis sustains a hyperextension injury in a motor vehicle accident. He presents with 2/5 motor strength in his upper extremities and 4/5 motor strength in his lower extremities. What spinal cord injury syndrome does this represent?

Explanation

Central cord syndrome classically occurs after hyperextension injuries in patients with pre-existing cervical stenosis. It presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

Question 93

When evaluating an adult patient for spinal deformity correction, achieving spinopelvic harmony is a primary goal. To minimize the risk of adjacent segment disease and mechanical failure, the lumbar lordosis (LL) should ideally be matched to within 10 degrees of which specific pelvic parameter?

Explanation

Pelvic incidence (PI) is a fixed morphological parameter unique to each individual. Achieving a PI-LL mismatch of less than 10 degrees is a critical goal in adult spinal deformity surgery to restore proper sagittal balance.

Question 94

A 45-year-old man presents to the emergency department with acute urinary retention, saddle anesthesia, and bilateral lower extremity weakness following a heavy lifting event. What is the most consistent early clinical finding in cauda equina syndrome?

Explanation

Urinary retention resulting in overflow incontinence is the most consistent and highly sensitive finding in established cauda equina syndrome. This presentation warrants urgent surgical decompression.

Question 95

A 34-year-old man is involved in a high-speed MVC. Imaging shows a bilateral pars interarticularis fracture of C2 with >3 mm of translation and severe angulation. This represents a Levine-Edwards Type II fracture. What is the primary mechanism of injury for this fracture pattern?

Explanation

A Levine-Edwards Type II Hangman's fracture is characterized by significant translation and angulation. It typically results from initial hyperextension followed by rebound flexion coupled with an axial load.

Question 96

A 50-year-old woman presents with numbness in her right ring and small fingers, along with weakness in hand grip. Which of the following physical examination findings would best differentiate a C8 radiculopathy from cubital tunnel syndrome?

Explanation

The flexor pollicis longus is innervated by the anterior interosseous nerve (a branch of the median nerve) but derives its root supply from C8. Its weakness indicates a C8 radiculopathy, as it is completely spared in ulnar nerve entrapment.

Question 97

A 22-year-old man was wearing a lap belt during a head-on collision. Radiographs demonstrate a flexion-distraction injury (Chance fracture) through the L2 vertebral body and posterior elements. Which of the following concomitant injuries must be carefully ruled out?

Explanation

Chance fractures are flexion-distraction injuries highly associated with lap-belt use. Up to 50% of patients with this fracture pattern have concomitant intra-abdominal injuries, particularly hollow viscus rupture.

Question 98

A 78-year-old woman with a history of severe osteoporosis presents with acute-onset, severe mid-back pain after coughing. MRI confirms an acute T11 compression fracture without posterior wall involvement or neurologic deficit. She has failed 6 weeks of aggressive conservative management including bracing and analgesics. What is the most appropriate next step?

Explanation

Vertebral augmentation techniques like kyphoplasty or vertebroplasty are indicated for osteoporotic compression fractures causing debilitating pain that persists despite 4 to 6 weeks of adequate nonoperative management.

Question 99

A 42-year-old man develops acute, severe anterior thigh pain and weakness in knee extension. MRI of the lumbar spine reveals a far-lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

Explanation

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

Question 100

A 65-year-old woman with long-standing rheumatoid arthritis presents with neck pain and mild myelopathic signs. Flexion-extension radiographs demonstrate an atlantodens interval (ADI) of 11 mm. What is the most critical radiographic parameter to assess the true space available for the spinal cord?

Explanation

The posterior atlantodens interval (PADI) measures the actual space available for the spinal cord. It is the most reliable predictor of neurologic deficit in rheumatoid atlantoaxial instability, with values less than 14 mm strongly indicating a need for surgical stabilization.

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

Orthopedic Spine 2026 MCQs: Board Review Questions & Answers (Part 4)

Key Takeaway

Orthopedic Spine 2026 MCQs: Board Review Questions & Answers (Part 4)

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