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6. Spine MCQs

Practice Set 115 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2281

Topic: 6. Spine

A 75-year-old woman reports persistent severe low back pain after lifting a bag of groceries 8 weeks ago. She denies the presence of any lower extremity pain, weakness, or other symptoms. AP and lateral lumbar spine radiographs are shown in Figures 47a and 47b. For further evaluation, what imaging study should be obtained next? Review Topic

. Lumbar spine flexion and extension radiographs
. Lumbar spine CT
. Lumbar spine MRI
. Whole body bone scan
. Tagged white blood cell scan

Correct Answer & Explanation

. Lumbar spine flexion and extension radiographs

Explanation

The radiographs show a L1 vertebral compression fracture. MRI scans of the lumbar spine are indicated to help determine the age of the fracture via evaluation of the fat-suppressed T2-weighted images. If those images show edema (bright signal) within the fracture, it can be assumed to be an acute or subacute fracture. Also, MRI scans may help further characterize the fracture as a benign osteoporosis-related fracture versus a pathologic fracture. Lastly, MRI scans allow for evaluation of the absence, presence, and degree of spinal stenosis. Although a lumbar spine CT scan is also a good option as a next step, given that the patient has a known fracture as seen on the radiographs, MRI scans will likely provide more relevant information in this case. A CT scan may assist in the evaluation of the posterior vertebral body wall and posterior elements in patients with burst fractures. A three-phase bone scan is a good alternative for the evaluation of the acuity of vertebral compression fractures in patients who have a contraindication to MRI scans. Flexion-extension radiographs are most commonly used to evaluate for instability and will not help determine the age of this fracture. Tagged white blood cell scans are performed to evaluate for infection, which is highly unlikely in this patient.

Question 2282

Topic: 6. Spine
A high school athlete reports the sudden onset of low back pain while performing a dead lift. Examination reveals lumbar paraspinal spasm and a positive straight leg raising test. Deep tendon reflexes, motor strength, and sensation in the lower extremities are normal. Radiographic findings are normal. If symptoms persist for longer than a few weeks, what is the best course of action?
. Electromyography and nerve conduction velocity studies
. MRI
. CT
. Bone scan
. Psychiatric evaluation

Correct Answer & Explanation

. MRI

Explanation

In the adolescent population, a lumbar herniated disk is characterized by a paucity of clinical findings, with a positive straight leg raising test the only consistently positive finding. An adolescent who lifts weights and has a history of back pain that fails to respond to a short period of active rest should undergo MRI evaluation for the diagnosis of a lumbar herniated disk.

Question 2283

Topic: 6. Spine
A 58-year-old man has had increasing midback pain for 8 weeks. Radiographs reveal mild osteopenia and mild disk degeneration but no fractures or lesions. An MRI of the spine reveals diskitis with a small-intensity signal within the spinal canal that is consistent with an epidural abscess at T11-12. The patient is neurologically intact but in significant pain. CT-guided biopsy of the disk space is positive for methicillin-sensitive Staphylococcus aureus. What is the most appropriate treatment?
. Intravenous (IV) antibiotics for 6 weeks and clinical observation
. Observation and bracing alone
. Laminectomy and posterior spinal fusion with IV antibiotics
. Anterior spinal debridement and fusion with IV antibiotics

Correct Answer & Explanation

. Intravenous (IV) antibiotics for 6 weeks and clinical observation

Explanation

The treatment of spinal infections is variable. A diskitis in a patient with a mechanically stable spine without neurologic compromise is typically treated with needle biopsy/culture and appropriate IV antibiotics. Epidural abscess often is considered one of the true orthopaedic emergencies that necessitates surgical intervention. However, there is growing evidence that medical management can be appropriate to treat epidural abscesses in certain cases. In cases involving neurologic deterioration, surgical decompression, drainage, and systemic IV antibiotics is the treatment of choice. Medical management of spinal abscesses can be considered when a patient refuses surgical decompression; surgery is contraindicated because of high risk, pain, or infection; or paralysis lasting longer than 24 to 36 hours results in a likely inability to reverse the paralysis. Patients who are neurologically intact may also be treated with medical management alone if they are stable and have an identifiable microorganism that can be observed closely to assess for neurologic deterioration. If neurologic changes are noted, surgical decompression and debridement and continued IV antibiotic therapy are appropriate.

Question 2284

Topic: 6. Spine
Which factor should most influence a patient's decision to have surgery for adult scoliosis if he or she is younger than age 50?
. Increasing coronal plane deformity
. Increasing pain
. Increasing sagittal balance
. Invasiveness of the surgical procedure

Correct Answer & Explanation

. Increasing coronal plane deformity

Explanation

In a retrospective review of 137 patients treated surgically and 153 patients treated nonsurgically for adult scoliosis, Bess and associates found that surgical treatment for patients younger than 50 years of age was driven by increased coronal plane deformity, and surgical treatment for older patients was mandated by pain and disability. They also concluded that age, comorbidities, and sagittal balance did not influence treatment decisions.

Question 2285

Topic: 6. Spine

A patient with a history of chronic low back pain for several years reports decreased pain visual analog scores with the home use of a transcutaneous electrical neuromuscular stimulation (TENS) unit. This pain relief is most likely due to which of the following?

. Improved skeletal muscle strength and secondary spinal support
. Neuromodulation via presynaptic inhibition in the dorsal horn of the spinal cord
. Distraction sensory input
. Enhancement of muscle metabolic activity with improved lactic acid excretion
. Placebo effect

Correct Answer & Explanation

. Improved skeletal muscle strength and secondary spinal support

Explanation

TENS units deliver superficial electrical stimulation. This electrical stimulation induces analgesia via inhibitory effects at the spinal cord level. The stimulation of small myelinated afferent fibers produces a presynaptic inhibition of the nociceptive transmission via unmyelinated C fibers, thus decreasing the transmission of pain stimuli. Additional benefit may come from the endogenous release of endorphins in the stimulated tissues.

Question 2286

Topic: 6. Spine
  • In a patient with T10-level spinal cord injury, which of the following prognostic signs most likely suggests functional recovery in the lower extremities?
. T10 sensory pin-prick level
. Retained vibratory sensation at the ankles
. Presence of sacral sparing
. Retained spontaneous respiratory function
. Priapism

Correct Answer & Explanation

. T10 sensory pin-prick level

Explanation

Sacral sparing is evidenced by perianal sensation, rectal motor function and great toe flexor activity. Presence of sacral sparing indicates an incomplete cord injury and the potential of more function after the resolution of spinal shock. If there is no evidence of spinal cord function below the level of the injury, including sacral sparing, and the bulbocavernosus reflex has not returned, no determination can be made regarding the completeness of the lesion.

Question 2287

Topic: 6. Spine
Degenerative spondylolisthesis of the cervical spine is most commonly seen at which of the following levels?
. C1-2
. C3-4
. C5-6
. C6-7
. C7-T1

Correct Answer & Explanation

. C3-4

Explanation

Degenerative spondylolisthesis of the cervical spine is seen almost exclusively at C3-4 and C4-5; this is in contrast to degenerative changes, which are most commonly seen at C5-6 and C6-7.

Question 2288

Topic: 6. Spine
The best patient-related outcomes, following the surgical treatment of cauda equina syndrome secondary to a large L5-S1 disk herniation, are most closely related to which of the following?
. Extent of bowel and bladder dysfunction
. Extent of the motor deficit
. Extent of the perianal saddle anesthesia
. Timing of surgery
. Location of the herniation

Correct Answer & Explanation

. Timing of surgery

Explanation

DISCUSSION: The most predictable positive outcome from spinal surgery due to a cauda equina syndrome is early surgical intervention before any significant neurologic deficit develops. Meta-analysis studies demonstrate that surgical intervention more than 48 hours after the onset of cauda equina syndrome shows an increased risk for poor outcomes.

Question 2289

Topic: 6. Spine

An 18-year-old man who sustained a lumbar fracture-dislocation with an associated complete spinal cord injury 6 weeks ago underwent instrumented posterior thoracolumbar fusion a few days after the injury. While at a rehabilitation facility, routine postoperative surveillance radiographs are obtained (Figures 11a through 11d). What is the most appropriate next step in management? Review Topic

. Observation alone with continued rehabilitation of the spinal cord injury
. Thoracolumbosacral orthosis bracing for 3 months
. Revision and extension of the posterior instrumentation and fusion
. Anterior lumbar corpectomy and fusion
. Anterior/posterior lumbar decompression and fusion

Correct Answer & Explanation

. Observation alone with continued rehabilitation of the spinal cord injury

Explanation

The patient has sustained a traumatic spondylolisthesis at the level below the caudal instrumented level, likely not appreciated at the index surgery. Surveillance radiographs indicate that there is significant translation in the lumbar spine on sitting, indicating an unstable injury. The lack of significant bony involvement indicates that the injury is predominantly through the anterior and posterior ligamentous complexes, and thus is unlikely to stabilize with nonsurgical management. Because the patient reduces almost completely on lying supine, the most appropriate course of action is extension of the posterior fusion to include the level of the instability. Because the patient has a complete spinal cord injury below the level of the thoracic fracture, decompression is not indicated.

Question 2290

Topic: 6. Spine
A 19-year-old linebacker for a collegiate football team has had two episodes of bilateral arm tingling and weakness after tackling; the symptoms resolved after 30 minutes of rest. Three follow-up neurologic examinations have been normal. Cervical spine CT and MRI scans are shown in Figures 13a through 13c. What is the next best step in management?
. The addition of a neck roll to the helmet and continuation of play
. Electrodiagnostic studies
. A series of epidural steroid injections, followed by a return to play
. Methylprednisolone dose pack, followed by a return to play in 1 week
. No further participation in football

Correct Answer & Explanation

. No further participation in football

Explanation

DISCUSSION: Cervical spinal stenosis is a contraindication to participation in collision and contact sports. This patient has symptomatic stenosis and should not be cleared for contact sports. A neck roll will not prevent neurologic injury in the presence of cervical spinal stenosis. Electrodiagnostic studies are not likely to add any additional significant findings with central canal stenosis. Cervical traction is not of value in the long-term. Epidural steroid injections or a methylprednisolone dose pack are not of value in this situation.

Question 2291

Topic: 6. Spine
Intradiskal electrothermal therapy (IDET) uses an intradiskal catheter to deliver controlled thermal energy to the inner periphery of the annulus fibrosis of a chronically painful intervertebral disk. Lumbar diskography is used diagnostically to identify the presumed pain generator to be targeted with IDET. Based on the medical literature, what can be said about the current status of IDET?
. IDET has been proven to seal annular tears in the annulus fibrosis.
. IDET restores segmental stability by shrinking collagen fibrils in the disk.
. IDET has demonstrated no significant benefit over placebo in controlled trials.
. IDET is an unsafe procedure with significant risk of permanent complications.
. IDET has demonstrated poor clinical results in all reported series to date.

Correct Answer & Explanation

. IDET has demonstrated no significant benefit over placebo in controlled trials.

Explanation

DISCUSSION: Intradiskal electrothermal therapy (IDET) initial clinical results were reported in 2000. The early case series were quite encouraging with reported therapeutic success rates of 60% to 80%. Since those early case studies, a few level I evidence studies have been conducted, one by Freeman and associates and one by Pauza and associates. These randomized, placebo-controlled trials demonstrated no significant benefit of IDET over the placebo.

Question 2292

Topic: 6. Spine
A 56-year-old man with a history of chronic lower back pain from lumbar spondylosis reports a 2-day history of acute incapacitating back pain. He denies any history of acute trauma, although he reports the pain starting after a coughing spell. He also reports difficulty urinating and some fecal incontinence. Examination reveals generalized lower extremity weakness, saddle paresthesia, hyporeflexia in the lower extremities, and loss of rectal tone. What is the most appropriate management at this time?
. Immediate MRI of the lumbar spine
. General reassurance, anti-inflammatory drugs, and an early home exercise program
. Immediate radiographs of the lumbar spine and pain medications with 2 days of bed rest if the radiographs are normal
. Office caudal epidural steroid injection with follow-up in 1 week
. Outpatient MRI of the lumbar spine with follow-up in 1 week for test results

Correct Answer & Explanation

. Immediate MRI of the lumbar spine

Explanation

Cauda equina syndrome is a medical emergency that must be quickly diagnosed and treated to avoid long-term complications. Cauda equina syndrome typically presents with low back pain, unilateral or usually bilateral sciatica, saddle sensory disturbances, bladder and bowel dysfunction, and variable lower extremity motor and sensory loss. Although a number of pathologies can cause cauda equina syndrome, in a patient with a history of chronic back pain, disk pathology is the most common cause of acute onset cauda equina syndrome. Whereas radiographs may be useful in a traumatic onset of symptoms, MRI is the most appropriate study. Cauda equina syndrome should be evaluated on an emergent basis and admission for work-up is appropriate.

Question 2293

Topic: 6. Spine
  • A 31-year-old man who is a recent immigrant from Guatemala has had pain in his back and thighs for the past 12 months. History notes a recent diagnosis of gout, and the patient reports falling a distance of 3 feet on his buttocks immediately before the pain began. Examination reveals that he is neurologically intact. Plain radiographs are shown in Figures 44a and 44b, and T2-weighted MRI scans are shown in Figures 44c and 44d. The most likely cause of the pathologic fracture is
. gout.
. osteoporosis.
. eosinophilic granuloma.
. tuberculosis of the spine.
. metastatic disease of the spine.

Correct Answer & Explanation

. gout.

Explanation

The plain films demonstrate lumbar AP and Lateral radiographs with 32 degree anteriorly wedged compression fracture of L1. On closer evaluation one notices the adjacent disc spaces are narrowed. The center of the vertebra is sclerotic with the anterior inferior endplate irregular.The MR demonstrates involvement of L1 and adjacent disc spaces. With peri-vertebral edema and mass involving the posterior aspect of the vertebral body, placing pressure on the spinal cord. There is also involvement of the L2-3 disc with early signal changes.The slow clinical course of the patients symptoms, being from a third world country and the findings on imaging studies, with an anterior wedge compression fracture. The level most commonly involved with TB is lower thoracic and upper lumbar. The anterior wedging results in the classic “Gibbus”.Some of the MR findings are also consistent with metastatic disease, but with the localized mass, peri-vertebral abscess make this choice more unlikely.The usual findings on MR found with TB are: Confluently decreased signal intensity of the vertebral bodies associated interspace with poor distinction between these on short TR/short TE images: Abnormal increased signal of the disk on long TR/long TE images with an abnormal configuration (i.e., absent intranuclear cleft): Increased signal of the vertebral endplates at the abnormal disk level on long TR/long TE images.

Question 2294

Topic: 6. Spine
A 42-year-old female with chronic discogenic back pain undergoes lumbar spine surgery via retroperitoneal approach. Figure A is the postoperative radiograph of her lumbar spine. Six weeks after the surgery the patient develops worsening low back pain. You obtain a radiograph of her lumbar spine, pictured in Figure B. What is the next best step in management?
. Facet joint injection and lumbosacral orthosis
. Posterior stabilization
. Revision arthroplasty via far lateral approach
. Revision to arthrodesis via far lateral approach
. Revision to arthrodesis via retroperitoneal approach

Correct Answer & Explanation

. Revision to arthrodesis via retroperitoneal approach

Explanation

This patient has a failed lumbar total disc replacement (TDR) with anterior dislocation of the polyethylene inlay and requires revision surgery, either revision arthroplasty or anterior interbody fusion, via retroperitoneal approach. Management of failed TDR is dictated by (1) patient symptoms and (2) radiographic implant position. Asymptomatic patients with implant subsidence without extrusion can be managed with close observation. Patients with persistent symptomatic back pain relating to facet joint or implant microinstability in the setting of an otherwise well-positioned TDR can be treated with posterior stabilization alone. Symptomatic patients with unacceptable implant position (i.e. complete dislodgement, fracture) require either revision arthroplasty or conversion to arthrodesis (anterior +/- posterior).

Question 2295

Topic: 6. Spine
A 44-year-old woman has had lower extremity dysesthesias, urinary incontinence, and has been unable to walk for the past 2 days. She reports no pain or history of trauma. She notes that 3 weeks ago she missed work for 2 days because of back pain, but it resolved with rest. Examination shows decreased or absent sensation below the knees, no motor function below the knees, and decreased rectal tone. Catheterization results in a postvoid residual of 2,000 mL. Plain radiographs and MRI scans without contrast are shown in Figures 1a through 1d. What is the next most appropriate step in management?
. Physical therapy for functional rehabilitation
. CT/myelography of the spinal axis
. MRI with gadolinium
. Psychiatric consultation for possible malingering
. Lumbar puncture for analysis of cerebrospinal fluid

Correct Answer & Explanation

. MRI with gadolinium

Explanation

DISCUSSION: The patient has had a clear and sudden onset of a profound neurologic deficit. The radiographic studies suggest a lesion in the conus medullaris that appears to be intradural and intramedullary. MRI, with and without contrast, will best evaluate this mass further. The addition of gadolinium allows further evaluation of vascularity and the extent of the lesion.

Question 2296

Topic: 6. Spine
Which of the following substances is least likely to affect the success of bone union after lumbar arthrodesis?
. Ketorolac
. Indomethacin
. Oxycodone hydrochloride
. Ibuprofen
. Nicotine

Correct Answer & Explanation

. Oxycodone hydrochloride

Explanation

DISCUSSION: Much attention has been given to the use of supplemental postoperative analgesia with nonsteroidal anti-inflammatory drugs (NSAIDs), and a significant reduction in narcotic use has been recorded. However, a high failure rate of arthrodesis has been associated with the use of postoperative NSAIDs. Glassman and associates reported 29 cases of pseudarthrosis in 167 patients when ketorolac was used as a postoperative analgesic, whereas only five fusion failures were noted in 121 patients not using ketorolac. Indomethacin and ibuprofen have been shown to adversely affect bone formation in clinical and animal trials. Nicotine has also been shown in a number of studies to decrease the fusion rate. Oxycodone hydrochloride is a synthetic morphine and does not affect the fusion process.

Question 2297

Topic: 6. Spine
What structure is most at risk for injury from a retractor against the tracheoesophageal junction during an anterior approach to the cervical spine?
. Esophagus
. Trachea
. Superior laryngeal nerve
. Recurrent laryngeal nerve
. Sympathetic chain

Correct Answer & Explanation

. Recurrent laryngeal nerve

Explanation

DISCUSSION: Although any of these structures can be injured by pressure from the medial blade of a self-retaining retractor, the recurrent laryngeal nerve runs cephalad in the interval between the esophagus and trachea and is vulnerable to pressure if caught between the retractor and an inflated endotracheal tube balloon.

Question 2298

Topic: 6. Spine
What is the primary reason for including the ilium in the distal fixation of long instrumentation constructs in adult scoliosis?
. Better coronal balance
. Better pelvic balance
. Reduced fretting and corrosion
. Improved curve correction
. Improved fusion success

Correct Answer & Explanation

. Improved fusion success

Explanation

DISCUSSION: Studies have shown that when compared with fixation to the sacrum alone, the success rate of fusion across the lumbosacral junction increases when both the sacrum and ilium are included in the posterolateral construct. Curve correction, coronal balance, and pelvic balance are all attended to within the thoracolumbar spine and are not directly related to the pelvic fixation. Fretting and corrosion are a byproduct of metal-to-metal connections.

Question 2299

Topic: 6. Spine
A 45-year-old man undergoes an anterior cervical diskectomy and fusion at C5-6 and C6-7 with instrumentation. During the first postoperative visit at 1 week, the patient reports difficulty swallowing and mild anterior cervical tightness. The anterior wound is benign and the patient denies any dyspnea or shortness of breath. A postoperative radiograph is seen in Figure 25. What is the most appropriate management at this time?
. Admit for observation and reassurance
. Surgical exploration and removal of the anterior instrumentation
. Esophageal swallowing study
. Soft cervical collar and early range-of-motion exercises
. CT of the cervical spine

Correct Answer & Explanation

. Admit for observation and reassurance

Explanation

The radiograph shows significant prevertebral soft-tissue swelling following a two-level anterior cervical diskectomy and fusion. Dysphagia after anterior cervical spine surgery is a common early finding that generally decreases significantly by 6 months with nonsurgical management.

Question 2300

Topic: 6. Spine
A 30-year-old man reports pain and weakness in his right arm. Examination reveals grade 4 strength in wrist flexion and elbow extension, decreased sensation over the middle finger, and decreased triceps reflex. These symptoms are most compatible with impingement on what spinal nerve root?
. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C7

Explanation

Motor impulses to the triceps, wrist flexion and elbow extension, and sensation to the middle finger are associated most commonly with the C7 root.

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