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6. Spine MCQs

Practice Set 112 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 2221

Topic: 6. Spine

A 35-year-old rock climber sustains an L1 burst fracture from a 30-foot fall while climbing. He sustained no other fractures or serious injuries. He is neurologically intact and has minimal posterior tenderness without increased spinous process separation on examination. Radiographs reveal kyphosis of 20 degrees between T12 and L2 with 30% vertebral height loss. A CT scan shows 55% canal compromise. What is the most appropriate management? Review Topic

. Bed rest for 6 weeks, followed by a thoracolumbosacral orthosis (TLSO) until the fracture is healed
. TLSO and or body cast for 3 to 6 months with mobilization when comfortable
. Posterior spinal fusion and instrumentation
. Anterior decompression with spinal fusion and instrumentation
. Anterior decompression and anterior-posterior spinal fusion and instrumentation

Correct Answer & Explanation

. Bed rest for 6 weeks, followed by a thoracolumbosacral orthosis (TLSO) until the fracture is healed

Explanation

Wood and associates have shown that the use of a TLSO or a body jacket was equally effective as surgery for the treatment of thoracolumbar burst fractures without neurologic deficit. The only difference in any of the measured parameters (including pain, functional outcome, residual canal compromise, and kyphosis) was a decreased complication rate in the nonsurgical group compared with the surgical group. The maximum time to mobilization in the nonsurgical group was 5 days.

Question 2222

Topic: 6. Spine

The risk for postoperative wound infection after lumbar spine surgery is reduced most by the use of

. iodine-impregnated preparation solution.
. chlorhexidine-impregnated preparation solution.
. greater than 10 minutes of surgical scrub.
. intravenous antibiotic prophylaxis prior to skin incision.
. laminar-flow air circulation.

Correct Answer & Explanation

. iodine-impregnated preparation solution.

Explanation

By far, the most impact on lowering the incidence of perioperative site infections after lumbar surgery is achieved by the use of intravenous perioperative antibiotics that are infused prior to skin incision. Ideally, these are administered within 1 hour of incision time. The use of an iodine versus a chlorhexidine solution has not been demonstrated to influence infection after spinal surgery. While adequate hand washing is an important practice, scrubbing for more than 10 minutes is not critical. Laminar-flow air circulation has been demonstrated to be helpful in total joint arthroplasty; however, this has not been demonstrated in spinal surgery. Furthermore, it is not likely that its use would influence the rate of infection as much as perioperative antibiotic prophylaxis.

Question 2223

Topic: 6. Spine
What is the most common nonanesthetic-related reversible cause of changes in intraoperative neurophysiologic monitoring data?
. Pedicle screw misplacement
. Patient positioning
. Spinal cord ischemia
. Retractor placement
. Hypotension

Correct Answer & Explanation

. Patient positioning

Explanation

DISCUSSION: Patient positioning that results in local nerve compression, plexus traction, or improper neck alignment is the most common nonanesthetic-related cause of changes in intraoperative neurophysiologic monitoring data during spinal surgery.

Question 2224

Topic: 6. Spine
Figures 3a and 3b show the MRI scans of a patient with neck pain. What is the most likely diagnosis?
. Neurofibromatosis
. Multiple sclerosis
. Cervical spondylotic myelopathy
. Acute poliomyelitis
. Gaucher’s disease

Correct Answer & Explanation

. Neurofibromatosis

Explanation

DISCUSSION: Multiple neurofibromas result in marked foraminal enlargement as seen on the sagittal MRI scan. Collagen disorders leading to dural ectasia may show similar enlargement, but none of these is listed as a possible answer.

Question 2225

Topic: 6. Spine

Pedicle subtraction osteotomies (PSO) are commonly performed in the lumbar spine to treat sagittal imbalance. What is the most common complication following a PSO in the lumbar spine? Review Topic

. Pseudarthrosis
. Nerve root injury
. Spinal cord injury
. Aortic injury
. Dural tear

Correct Answer & Explanation

. Pseudarthrosis

Explanation

The rate of pseudarthrosis at 5-year follow-up is 29%, with most occurring at the thoracolumbar junction cephalad to the site of the PSO. The rate of postoperative neurologic deficits is 11%, with 2.8% resulting in permanent deficits. Spinal cord injury is rare because the PSO is typically performed in the lumbar spine below the conus.

Question 2226

Topic: 6. Spine
A previously healthy 29-year-old man reports a 2-day history of severe atraumatic lower back pain. He denies any bowel or bladder difficulties and no constitutional signs. Examination is consistent with mechanical back pain. No focal neurologic deficits or pathologic reflexes are noted. What is the most appropriate management?
. Radiographs, including anterior, lateral, and oblique views
. MRI of the lumbar spine and follow-up at the clinic in 1 week
. Caudal epidural steroid injection
. Reassurance, limited analgesics, and early range of motion as tolerated
. Immediate MRI of the lumbar spine and possible urgent surgical decompression

Correct Answer & Explanation

. Reassurance, limited analgesics, and early range of motion as tolerated

Explanation

In general, a previously healthy patient with an acute onset of nontraumatic lower back pain does not need diagnostic imaging before proceeding with therapeutic treatment. In the absence of any “red flags” during the history and physical examination, the appropriate treatment for acute onset lower back pain is purely symptomatic treatment including limited analgesics and early range of motion.

Question 2227

Topic: Thoracolumbar Spine & Deformity

Which of the following conditions routinely requires early surgical intervention in patients with Marfan syndrome? Review Topic

. Kyphosis
. Ankle instability
. Protrusio acetabula
. Progressive scoliosis
. Pseudarthrosis of the tibia

Correct Answer & Explanation

. Kyphosis

Explanation

Marfan syndrome is a challenging disease for the orthopaedic surgeon. Most problems of joint laxity, acetabular protrusio, and minor scoliosis curves are treated nonsurgically. Pseudarthrosis of the tibia is not seen in Marfan syndrome; it is more common in patients with neurofibromatosis (NF-1). Treating kyphosis is risky for vertebral subluxation. Rapidly progressive scoliosis in immature patients is associated with higher surgical complications, but surgery is indicated. Overcorrection is associated with significant cardiovascular complications and should be avoided.

Question 2228

Topic: 6. Spine
In the treatment of thoracic disk herniations, what approach is associated with the highest risk of iatrogenic paraplegia?
. Laminectomy
. Costotransversectomy
. Transpedicular
. Transthoracic
. Thoracoscopic

Correct Answer & Explanation

. Laminectomy

Explanation

Laminectomy is associated with the highest risk of iatrogenic paraplegia because retraction on the cord is necessary for visualization, but retraction is difficult because of tethering of the intradural dentate ligaments. All of the other approaches allow for access to the disk herniation through an angle that avoids the cord itself, although other limitations may exist.

Question 2229

Topic: Thoracolumbar Spine & Deformity

Figure 37 shows the standing lateral radiograph of a 62-year-old woman who reports lower back pain and the inability to stand upright. What permanent anatomic pelvic parameter should be measured and considered when determining the amount of lumbar lordosis correction that will be necessary to obtain sagittal balance? Review Topic

. Pelvic tilt
. Pelvic incidence
. Sacral slope
. Acetabular version
. Femoral version

Correct Answer & Explanation

. Pelvic tilt

Explanation

Pelvic incidence (PI) is the anatomic angle between the sacral end plate and a line connecting the center of the femoral heads. Increased pelvic incidence has been found to correlate with the incidence and severity of spondylolisthesis. Patients with increased PI require increased lumbar lordosis to restore sagittal balance. Pelvic tilt (PT) and sacral slope (SS) have also been found to correlate with lumbar lordosis; however, both PT and SS can change depending on pelvic rotation. PI is the onlypermanent pelvic parameter that is unaffected by pelvic rotation. Acetabular and femoral version have not been found to be associated with lumbar lordosis.

Question 2230

Topic: 6. Spine
When using surgery extending to the pelvis to treat long spinal deformity in adults, the addition of anterior interbody structural support at the lumbosacral junction serves what biomechanical function?
. Improves the bone mineral density of the vertebral bodies
. Reduces the strain at the adjacent intervertebral disk
. Reduces the stiffness of the posterior instrumentation
. Reduces the strain on posterior instrumentation
. Increases the strength of the posterior instrumentation

Correct Answer & Explanation

. Reduces the strain on posterior instrumentation

Explanation

Shufflebarger and others have reported that the placement of anterior interbody structural support at the lumbosacral junction increases the overall construct stiffness and reduces the strain on posterior instrumentation, thereby reducing the risk of screw pull-out or fracture. The stiffness of the posterior instrumentation actually increases, whereas the actual strength of the instrumentation remains the same. Actual strain measured at an adjacent intervertebral disk to a fusion construct is expected to increase.

Question 2231

Topic: 6. Spine
What is the most important sign of impending modulation with rapid progression of a spinal deformity in neurofibromatosis?
. Apical curve rotation
. Anterior vertebral body erosions
. Cervical spine involvement
. Penciling of three or more ribs
. Curve magnitude of more than 50 degrees

Correct Answer & Explanation

. Penciling of three or more ribs

Explanation

Rib penciling is the only singular factor; 87% of the curves progressed significantly in patients with three or more penciled ribs. Modulation in neurofibromatosis scoliosis implies the change from an idiopathic type to a dysplastic type of curve with rapid progression and the need for aggressive stabilization by fusion.

Question 2232

Topic: Thoracolumbar Spine & Deformity

The most important radiographic predictor of a good clinical outcome following adult spinal deformity surgery is correction of Review Topic

. pelvic incidence.
. listhesis.
. rotational deformity.
. sagittal balance.
. coronal deformity.

Correct Answer & Explanation

. pelvic incidence.

Explanation

Surgery for adult deformity, such as degenerative scoliosis and kyphosis, has gained popularity in recent years. Improved fixation techniques, such as pedicle screws, and increased familiarity and comfort with anterior surgery have resulted in greater curve correction. Multiple studies have demonstrated that correction of sagittal balance is the most important radiographic predictor of a good clinical outcome. While correction of coronal deformity is often a surgical goal, it does not appear to be as important in improving patient outcomes. Correction of listhesis, particularly in the surgical treatment of adult spondylolisthesis, is controversial because its impact on clinical outcomes has not been clearly established. Rotational deformities, though often present with adult scoliosis, are difficult to correct. Pelvic incidence is a fixed parameter that is unchanged with surgery.

Question 2233

Topic: 6. Spine
The 5-year outcome for patients with sciatica secondary to lumbar disk herniation shows which of the following results?
. Patients have the same likelihood of receiving disability whether treated with or without surgery.
. Sixty percent of surgically treated patients undergo at least one more operation within 5 years.
. Only 20% of patients treated with surgery report improved symptoms of back and/or leg pain.
. A smaller portion of surgical patients, compared to nonsurgically treated patients, report improvement.
. Fifty percent of patients treated nonsurgically seek surgery within 5 years.

Correct Answer & Explanation

. Patients have the same likelihood of receiving disability whether treated with or without surgery.

Explanation

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

Question 2234

Topic: 6. Spine

What is the most common nonanesthetic-related reversible cause of changes in intraoperative neurophysiologic monitoring data? Review Topic

. Pedicle screw misplacement
. Patient positioning
. Spinal cord ischemia
. Retractor placement
. Hypotension

Correct Answer & Explanation

. Pedicle screw misplacement

Explanation

Patient positioning that results in local nerve compression, plexus traction, or improper neck alignment is the most common nonanesthetic-related cause of changes in intraoperative neurophysiologic monitoring data during spinal surgery.

Question 2235

Topic: 6. Spine
During the approach to the lumbar spine for an L4-L5 anterior lumbar interbody fusion, which structure generally is found overlying the anterior surface of the L4 vertebra?
. Aorta
. Right common iliac artery
. Left common iliac vein
. Right ureter

Correct Answer & Explanation

. Aorta

Explanation

During an anterior approach to the L4-L5 disk space for anterior lumbar interbody fusion, meticulous exposure is paramount to allow for safe preparation of the disk space and subsequent arthrodesis. Although all of these structures can come into play during the exposure, the aorta lies anterior to the L4 vertebral body and bifurcates at this level. The vena cava bifurcates just distal to this. The ureters lie to both sides of the anterior spine. The right common iliac artery and the left common iliac vein originate after the bifurcation of the great vessels and lie caudal to the L4 vertebra.

Question 2236

Topic: 6. Spine

A 17-year-old high school football linebacker sustains an injury while making a tackle. His initial symptoms are right shoulder pain, bilateral biceps weakness, and right arm numbness. The symptoms only last a few minutes, and he continues to play in the game. He tells his parents after the game, and they bring him to your office for evaluation the next day. He no longer has any symptoms, and his examination findings and cervical spine radiographs are normal. What is the best next step?

. Allow him to continue playing football
. Order an EMG
. Observe and if symptoms are negative for one week, then a return to football
. Order a cervical MRI scan

Correct Answer & Explanation

. Allow him to continue playing football

Explanation

The football player had bilateral weakness indicating that the injury was more significant than a stinger. Stingers present with unilateral symptoms, and if they resolve, an athlete can return to sports. However, bilateral symptoms indicate cervical spine pathology, such as spinal stenosis, and warrant an MRI scan of the cervical spine. Despite the patient being able to continue playing in the game and having symptom resolution, a cervical MRI scan should be performed prior to return to sports.

Question 2237

Topic: 6. Spine
A 65-year-old man with ankylosing spondylitis sustains an extension injury to his cervical spine. Two days later, a progressive neurologic deficit develops at the C6 level. An MRI scan is shown in Figure 1. What is the most likely diagnosis?
. Epidural hematoma
. Herniated disk
. Tumor
. Extruded epidural bony fragment
. Abscess

Correct Answer & Explanation

. Epidural hematoma

Explanation

DISCUSSION: It is common for patients with ankylosing spondylitis to sustain extension-type fractures, typically near the cervicothoracic junction. These fractures can be minimally displaced, making them difficult to diagnose. In addition, the vertebral bodies are vascular and their canals are relatively enclosed, making them vulnerable to epidural bleeding. The MRI scan shows an epidural hematoma posteriorly compressing the cord. REFERENCES: Bohlman HH: Acute fractures and dislocations of the cervical spine. J Bone Joint Surg Am 1979;61:1119-1142. Weinstein PR, Karpman RR, Gall EP, et al: Spinal cord injury, spine fracture and spinal stenosis in ankylosing spondylitis. J Neurosurg 1982;57:609-616. Johnson T, Steinbach L (eds): Essentials of Musculoskeletal Imaging. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, p 44.

Question 2238

Topic: 6. Spine

An elderly woman with radiographic evidence of spinal stenosis reports difficulty walking and calf pain that is relieved by rest and a change of position. The most likely cause of pain is ischemia of the

. Nerve roots
. Spinal cord
. Sciatic nerve
. Peroneal nerve
. Conus medullaris

Correct Answer & Explanation

. Nerve roots

Explanation

Pain and numbness in the buttock, thigh and legs during walking or prolonged standing in the upright posture-that is relieved by various postures-is caused by spinal stenosis. Neurogenic claudication may result from nerve root ischemia secondary to increased epidural pressure, intermittent compression of nerve roots and venous congestion.

Question 2239

Topic: 6. Spine
Figure 33 shows the MRI scan of a 55-year-old woman who has had a 6-week history of back and leg pain. Which of the following clinical scenarios is most consistent with the MRI scan findings at L4-L5?
. L4 nerve root radiculopathy
. L5 nerve root radiculopathy
. Associated bowel and bladder dysfunction
. Symptoms associated with arachnoiditis
. Wide-based gait, left-sided Hoffman’s sign

Correct Answer & Explanation

. L4 nerve root radiculopathy

Explanation

The MRI scan reveals a L4-L5 foraminal disk herniation originating from the L4-5 disk space that has migrated up into the foramen, compressing the left L4 nerve root. There is normal distribution of the roots in the cerebrospinal fluid, excluding arachnoiditis as a diagnosis, and disk herniation in this location would not result in cauda equina syndrome or myelopathy.

Question 2240

Topic: 6. Spine

A 2-year-old child is being evaluated for limb-length and girth discrepancy. As a newborn, the patient was large for gestational age and had hypoglycemia. Current examination shows enlargement of the entire right side of the body, including the right lower extremity and foot. The skin shows no abnormal markings, and the neurologic examination is normal. The spine appears normal.

. bone age of the left wrist.
. MRI of the spine.
. MRI of the brain.
. renal and abdominal ultrasonography.
. hip ultrasonography.

Correct Answer & Explanation

. bone age of the left wrist.

Explanation

The patient may have Beckwith-Wiedemann syndrome (BWS), which consists of exophthalmos, macroglossia, gigantism, visceromegaly, abdominal wall defects, and neonatal hypoglycemia. Hemihypertrophy develops in approximately 15% of patients with BWS. Patients with hemihypertrophy that is the result of BWS have a 40% chance of developing malignancies such as Wilms’ tumor or hepatoblastoma; therefore, frequent ultrasound screening is recommended until about age 7 years. The absence of nevi and vascular markings helps to rule out other causes of hemihypertrophy, such as neurofibromatosis, Proteus syndrome, and Klippel-Trenaunay syndrome. Bone age estimations are not accurate at this young age but may become more useful later to help predict the timing of epiphysiodesis procedures.

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