Free Orthopedic MCQs 2022, Dec, 16 | 12:00 am

ORTHOPEDIC MCQS ONLINE 015Spine

ORTHOPEDIC MCQS ONLINE SPINE

CLINICAL SITUATION FOR QUESTIONS 1 THROUGH 3

Figures 1a through 1d are the contrast-enhanced MR images of a 56-year-old man with a 2-week history of increasingly severe back pain. He denies any injuries to his back, fevers, or chills.

Question 1 of 100

What is the most likely diagnosis?

Degenerative disk disease
Disk herniation with spinal stenosis
Epidural and paraspinal abscess
Muscle strain

PREFERRED RESPONSE: 3- Epidural and paraspinal abscess

Question 2 of 100

Patients initially treated with intravenous (IV) antibiotics are at higher risk for failure of nonsurgical treatment in the setting of

obesity.
diabetes.
abscess extending over 3 vertebrae.
blood culture findings positive for coagulase-negative Staphylococci.

PREFERRED RESPONSE: 2- diabetes.

Question 3 of 100

Which clinical finding most strongly suggests that nonsurgical care should be discontinued and surgical intervention is necessary?

Progressive weakness
C-reactive protein (CRP) level of 75
Increased low-back pain
White blood cell (WBC) count of 11

PREFERRED RESPONSE: 1- Progressive weakness

DISCUSSION

Epidural abscesses are potentially devastating. Nonsurgical care may be chosen for select patients. A baseline failure rate of 8.3% increases based on patient risk factors, which include a history of IV drug abuse, diabetes, age older than 65, CRP level higher than 115, WBC level higher than 12.5, and Staphylococcus aureus as the causative organism. Immunosuppression and abscess size are not significant risk factors for failure of nonsurgical care. Nonsurgical care may be regarded as "failed" if there is worsening of a patient's neurologic status. When nonsurgical care fails, delayed surgery is less successful at restoring motor function (vs early surgery).

Question 4 of 100

Which factor is most important when attempting to prevent interbody graft subsidence?

End plate burring
Surface contact area
Bone quality
Use of rigid fixation

PREFERRED RESPONSE: 3- Bone quality

DISCUSSION

Osteoporosis can affect all aspects of spinal stability and is the most critical factor regarding spinal implant failure. Burring of the end plates may decrease strength of the interface with the uncovering of "softer" cancellous bone. Increasing the surface contact area may help prevent subsidence but is not as important as bone quality. Stress shielding through rigid fixation may lead to construct failure.

Question 5 of 100

Figure 5 is a T2-weighted MR image of a 26-year-old man who has had left leg pain for 3 months that has failed nonsurgical treatment. Surgical decompression is planned. Which approach would provide the most direct ability to perform surgical decompression?

Posterior midline approach
Retroperitoneal approach
Far lateral approach
Transpsoas approach

PREFERRED RESPONSE: 3- Far lateral approach

DISCUSSION

The MR image shows a far lateral disk herniation impinging on the exiting nerve root lateral to the exiting foramen. This is reached most directly with a far lateral (Wiltse) approach. This is a posterior paramedian approach that uses the interval between the paraspinal muscles (multifidus and longissimus) and arrives onto the facet joints. The intertransverse membrane can then be released, exposing the far lateral disk herniation. A posterior midline approach will allow easy access to the spinal canal, which is medial to the disk herniation, and will not allow for easy disk removal without the need for a facetectomy, which would destabilize the level. An anterior approach would not allow for access to the far lateral disk herniation, nor would a traditional retroperitoneal or newer transpsoas approach.

Question 6 of 100

Which intervention most effectively prevents surgical-site infections following spine surgery?

Bathing the day of surgery
Intravenous (IV) vancomycin
Preincision IV antibiotics
Vancomycin powder in wound

PREFERRED RESPONSE: 3- Preincision IV antibiotics

DISCUSSION

The use of IV antibiotics for prophylaxis of surgical-site infection is supported by Level 1 evidence in spine surgery. It has been given a "B" recommendation by the North American Spine Society. The use of specific bathing solutions the day of surgery may be beneficial, but the evidence in spine surgery is lacking. Similarly, evidence for use of vancomycin (either topically or IV) is not supported by high-level studies, although retrospective and basic science studies support topical vancomycin use.

Question 7 of 100

Figures 7a through 7d are the images of a 31-year-old obese woman who has a long history of low-back pain and intermittent bilateral lower extremity pain. Five days ago her symptoms increased markedly and she was given pain medications upon presentation to her primary care physician. Three days ago she noticed that her bed was wet upon awakening; she also had numbness and tingling in her peroneal area and lower extremities and weakness in her lower extremities. She is brought to your office in a wheelchair. Her examination reveals diminished sensation to light touch in the L4 to S4 dermatomes and 0-1/5 strength in all muscle groups in her bilateral lower

extremities with the exception of her hip flexors, hip adductors, and quadriceps, which are 5/5 in strength. She has decreased sphincter tone on rectal examination. You recommend immediate decompressive laminectomy. What is the likelihood she will regain bladder function after surgery?

1- 0% to 20%

2- 21% to 40%

3- 41% to 60%

4- 61% to 80%

PREFERRED RESPONSE: 2- 21% to 40%

DISCUSSION

This patient has congenital and acquired spinal stenosis with multilevel disk protrusions that have both chronic (calcified) and acute components, resulting is multilevel cauda equina compression and acute cauda equina syndrome of more than 48 hours duration. Most studies indicate that patients who undergo decompression within 48 hours of symptom onset have a better prognosis for neurologic recovery than those who undergo decompression after 48 hours. Among patients with urinary incontinence, 1 study indicated that 43% remained incontinent at follow-up visits, but this study included a mix of early and late surgical patients. In another series of 44 patients with acute cauda equina syndrome, chronic bowel and bladder dysfunction were issues for 63% of those for whom surgery was delayed for more than 48 hours after symptom onset.

Question 8 of 100

Among patients with adolescent idiopathic scoliosis, a thoracolumbosacral orthosis is most effective for which type of curve?

Apex of the curve is at T3
Apex of the curve is at T8
Apex of the curve is at L1
Apex of the curve is at L2

PREFERRED RESPONSE: 2- Apex of the curve is at T8

DISCUSSION

A thoracolumbosacral orthosis is most effective for bracing of curves when the apex is at T7 or below. Bracing is used for patients who are skeletally immature (Risser stage 0, 1, or 2), and it is recommended that the brace be worn 16 to 23 hours per day and continued until skeletal maturity or until the curve progresses to beyond 45 degrees, at which point bracing is no longer considered effective.

DISCUSSION

Interbody fusion, when compared to PLF, is a predictor of more substantial blood loss. Multilevel posterior lumbar interbody fusion (PLIF) is an independent predictor of blood loss for posterior spine fusion. Some retrospective studies suggest that fusion rates are higher for transforaminal lumbar interbody fusion (TLIF) than PLF, but this finding has not been borne out in prospective studies. The main advantage of TLIF in the context of this question is restoration of neuroforaminal height, and many surgeons will consider TLIF or PLIF for that reason. The parasagittal MR image seen in Figure 9c shows neuroforaminal narrowing. The pre- and postsurgical radiographs show a difference in neuroforaminal height.

RESPONSES FOR QUESTIONS 10 THROUGH 14

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

Please match the scenario described below with the most likely complication listed above.

Question 10 of 100

A 55-year-old man who has had multiple lumbar fusions during the last 10 years and a lumbar lordosis of 25 degrees notes difficulty standing upright without flexing his knees.

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

PREFERRED RESPONSE: 5- Sagittal imbalance

Question 11 of 100

An 80-year-old woman with osteoporosis and thoracic kyphosis has a spinal fusion from T12-S1.

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

PREFERRED RESPONSE: 3- Pedicle screw cut-

Question 12 of 100

A 65-year-old woman with diabetes has fever and erythema 2 weeks after undergoing instrumented spinal fusion.

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

PREFERRED RESPONSE: 1- Postoperative deep surgical site infection

Question 13 of 100

A 60-year-old man with a pelvic incidence of 75 degrees undergoes an instrumented fusion for degenerative scoliosis from T11-S1, achieving a lumbar lordosis of 50 degrees.

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

PREFERRED RESPONSE: 2- Proximal junctional kyphosis

Question 14 of 100

A 50-year-old woman undergoes an L4-S1 laminectomy and noninstrumented fusion for degenerative spondylolisthesis.

Postoperative deep surgical site infection
Proximal junctional kyphosis
Pedicle screw cut-out
Pseudarthrosis
Sagittal imbalance

PREFERRED RESPONSE: 4- Pseudarthrosis

DISCUSSION

Complications are numerous in adult spinal deformity surgery. Many complications are related to the patient's sagittal balance following surgery and recognition of the potential to develop sagittal imbalance or flat-back syndrome following spinal fusion. The quality of bone density is important in spinal instrumented fusions, especially among older patients. Patients with osteopenia or osteoporosis have a higher incidence of proximal-level screw cut-out through the vertebral body into the cephalad disk space.

Proximal junctional kyphosis is common in longer instrumented fusions, especially when instrumented to the sacrum/pelvis; when the spine is fixed in a "flat" or hypolordotic position; when the thoracic spine is hyperkyphotic (ie, Scheuermann kyphosis); when the end instrumented vertebrae is kyphotic; or when the sagittal plumb line (measured from C7) is more than 4 cm forward of the posterior corner of the sacrum.

Sagittal imbalance is a common complication when the spine is instrumented in a hypolordotic position. This can occur with degenerative conditions that necessitate multilevel fusions or fusions to sacrum without recognition of the degree of lordosis the patient should have. Pelvic incidence (PI) is a spinopelvic measurement that is a constant that measures an angle from the hips to the midpoint of the sacral end plate. PI correlates to the amount of lumbar lordosis that a patient would typically have in an upright position (+/-10 degrees). If a patient has significant sagittal imbalance, he or she will have a forward lean and lack the ability to extend the spine to stand upright. In an attempt to stand upright, the patient may bend his or her knees or hips in a crouched position. When extending their knees, they again lean forward.

Pseudarthrosis is common with noninstrumented fusions. Deep surgical-site infections are uncommon but can be major complications that are difficult to treat, necessitating formal irrigation and debridement and long-term antibiotics. Patients with diabetes have a higher incidence of infection.

Question 15 of 100

A 25-year-old athletic woman has a 16-week history of left lower-extremity radiating pain in an S1 distribution. MR images obtained by her family physician reveal a large L5-S1 paracentral disk herniation impinging on the left S1 nerve root. You suggest a left-sided L5-S1 microdiskectomy and tell her that when comparing tubular diskectomy and open procedures

there are no differences in functional outcome.
open diskectomy is associated with superior functional outcomes.
tubular diskectomy is associated with superior short- and long-term results.
tubular diskectomy is associated with inferior short-term results but superior long-term outcomes.

PREFERRED RESPONSE: 1- there are no differences in functional outcome.

DISCUSSION

Several comparative studies have reported no difference in functional outcomes between tubular diskectomy and microsurgical lumbar diskectomy. A recent systematic review by Kamper and associates in which conventional microdiskectomy and minimally invasive approaches were compared revealed that there was no difference between the procedures in terms of clinical outcomes, complication risk, or rate of revision surgery.

Question 16 of 100

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

PREFERRED RESPONSE: 1- Intravenous (IV) antibiotics for 6 weeks and clinical observation

DISCUSSION

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 17 of 100

While performing long fusion with osteotomies for a patient with adult scoliosis and sagittal plane deformity, the neurophysiologist reports a change in motor-evoked potentials in the lower extremities. What is the most appropriate next step?

Perform an immediate wake-up test
Continue with the surgery and reassess in 5 minutes
Administer intravenous methylprednisolone
Ensure that mean arterial blood pressure is 80 or higher

PREFERRED RESPONSE: 4- Ensure that mean arterial blood pressure is 80 or higher

DISCUSSION

The use of intraoperative neuromonitoring is expanding, especially in the setting of deformity surgery. Changes in monitoring are concerning for the possibility of a neurologic injury; however, several other factors can alter signals. These include hypotension, changes in anesthesia depth and medications, the use of paralytic agents, and technical issues such as leads falling out or becoming disconnected. If a change in neuromonitoring signals is noted, these factors should be checked first to rule out false-positive findings. If this does not correct the problem, the wound should be explored to ensure there is no compression on the neural elements. Finally, if the deformity has been corrected, some of the correction can be released in an attempt to improve the signals. A wake-up test is difficult to perform and does not provide specific information regarding the location of the problem or how to correct it. Steroids may be used depending on surgeon preference, but should not be used until neurologic injury is ruled out. Any neuromonitoring changes always necessitate immediate investigation.

Question 18 of 100

Figures 18a and 18b are the lumbar spine radiographs of a 72-year-old man with no significant medical history who has had severe back pain for 3 weeks. He denies radiating symptoms, weakness, or numbness when he is seen in the emergency department. He is sent home with a soft corset. At his followup visit he continues to describe significant back pain with activity that is not relieved with oral narcotic mediations. A follow-up CT scan shows a nondisplaced fracture through all 3 columns of the spine. What is the most appropriate treatment?

Nonsteroidal anti-inflammatory drugs (NSAIDS), physical therapy, and activity modification
Continued soft corset use
Thoracolumbosacral orthosis (TLSO) bracing
Posterior stabilization

PREFERRED RESPONSE: 4- Posterior stabilization

DISCUSSION

The patient has previously undiagnosed ankylosing spondylitis. Radiographs reveal nonmarginal syndesmophytes throughout the lumbar spine. The CT scan reveals a nondisplaced 3-column fracture. Many patients with missed spinal injuries present in followup with neurologic worsening or progressive deformity. Fractures can often involve all 3 columns, including the posterior elements. In patients with ankylosing spondylitis, this represents an unstable injury and a high likelihood of displacement with nonsurgical treatment. Surgical treatment in the form of a posterior spinal fusion is indicated. Because the fracture is nondisplaced and the patient is neurologically intact, decompression via an anterior approach is not indicated. Bracing either with a TLSO brace or a soft corset will not provide sufficient stability for this fracture pattern. Physical therapy and NSAIDS are not indicated in this scenario.

Question 19 of 100

Figures 19a and 19b are the CT scans of an 18-year-old man who was a restrained driver in a rollover motor vehicle collision. What was the primary mechanism of injury?

Axial load
Rotation
Extension
Distraction

PREFERRED RESPONSE: 4- Distraction

DISCUSSION

This injury pattern represents a flexion distraction injury, or a Chance fracture. The imaging hallmark of this injury is the axial split of the pedicle seen on the sagittal CT scan. This injury necessitates surgical intervention to prevent progressive deformity and pain. A rotation mechanism results in a dislocation with a rotational deformity at the level of injury. An extension force causes failure of the anterior column in tension with compression of the posterior column. An axial load force would result in a burst fracture.

Question 20 of 100

A number of potential complications are associated with the direct lateral approach to the lumbar spine; which complication is most common?

Infection
Iliopsoas weakness
Injury to the aorta
Foot drop

PREFERRED RESPONSE: 2- Iliopsoas weakness

DISCUSSION

Sofianos and associates examined the cases of 45 patients who underwent the lateral transpsoas approach and found that 18 of 45 patients (40%) experienced at least 1 complication. The most common complication was postsurgical weakness of the iliopsoas, which was an issue for 10 of 45 patients (22.2%). The second-most-common complication in this series was anterior thigh hypoesthesia. This occurred in 8 of 45 patients (17.8%). A series of 600 patients by Rodgers and associates noted that thigh pain and psoas weakness following a direct lateral approach to the lumbar spine were both "nearly universal" but almost "always transient."

CLINICAL SITUATION FOR QUESTIONS 21 AND 22

Figures 21a through 21c are the preoperative lateral standing radiograph, axial T2-weighted MR image at L4-5, and supine sagittal MR image of a 45-year-old woman who has had back and leg pain for 2 years. Treatment had included nonsteroidal anti-inflammatory drugs, physical therapy, and epidural corticosteroid injections. Her pain limited her activities of daily living; she could walk only 1 to 2 blocks before her pain became intolerable.

21A

Question 21 of 100

A lateral transpsoas interbody fusion with percutaneous pedicle screws was performed. When compared with those undergoing open laminectomy and fusion, this patient can expect

a longer hospital stay.
a higher complication rate.
higher risk for postoperative thigh pain.
no relief of lower extremity symptoms.

PREFERRED RESPONSE: 3- higher risk for postoperative thigh pain.

Question 22 of 100

The above surgery was performed with recombinant human bone morphogenetic protein-2 (rhBMP-2). She reports immediate relief of her leg pain and is discharged home on postoperative day 2. The patient reports new-onset radicular pain and weakness in her leg 1 year later. Figures 22a and 22b are her postoperative CT myelogram images. What is the most likely cause of her pain?

22A B

Excessive retraction of the traversing nerve root
Bony overgrowth from the use of BMP protein in the disk space
Osteomyelitis with compression of the nerve roots
Inadequate decompression after surgery

PREFERRED RESPONSE: 2- Bony overgrowth from the use of BMP protein in the disk space

DISCUSSION

Transient thigh pain after lateral, transpsoas interbody fusion is common and generally lasts for less than 3 months. Transpsoas interbody fusion with slip reduction can result in indirect spinal decompression and often obviates the need for a laminectomy for most patients. Complications with this approach are comparable to those experienced with open surgery, but the hospital stay is generally shorter.

Use of BMP in interbody devices has also become common. The images above show heterotopic bone growth into the spinal canal causing nerve compression. This complication is more commonly encountered after posterior lumbar interbody fusions.

Question 23 of 100

Standard guidelines necessitate the use of intraoperative neurophysiological monitoring for patients undergoing surgery for which condition?

Primary lumbar disk herniation
Adolescent idiopathic scoliosis
Cervical spondylotic myelopathy
No conditions; there are no official guidelines

PREFERRED RESPONSE: 4- No conditions; there are no official guidelines

DISCUSSION

There are currently no official guidelines on the appropriate use of neuromonitoring in spine surgery. In general, use of neuromonitoring is at surgeon discretion and often is based on the surgeon's perceived risk for neurologic injury during surgery and medicolegal concerns. In most reports,

neuromonitoring is considered useful in cases of deformity correction, spinal cord decompression, instrumentation placement, and revision surgery. However, even for some of these cases, studies have shown limited benefits of neuromonitoring and substantial associated costs.

Question 24 of 100

A 56-year-old man has upper thoracic pain after undergoing stereotactic radiosurgery for a blastic metastatic lesion in the vertebral body of T5. He has normal alignment without collapse, but the tumor involves the entire vertebral body. Which factor increases this patient's risk for a pathologic fracture?

Location of the lesion at T5
History of stereotactic radiation
Blastic nature of the tumor
Tumor involving all of the vertebral body

PREFERRED RESPONSE: 2- History of stereotactic radiation

DISCUSSION

Criteria for spinal instability have been outlined by the Spine Oncology Study Group, which developed the Spinal Instability Neoplastic Score (SINS) criteria. Factors associated with lower risk for instability/fracture are location outside of a junctional level (the SINS criteria use C7-T2 as the junctional level),

blastic metastases, and no evidence of vertebral collapse (even with more than 50% involvement). Radiation has been associated with risk for pathologic fracture, and stereotactic radiation has been associated with risk for a spinal fracture.

Question 25 of 100

What is the appropriate first step when confirming the diagnosis of a neurologically intact, 73-year-old man who has the images shown in Figures 25a through 25c?

Order a prostate-specific antigen (PSA) level
Perform a 2-level corpectomy and reconstruction with tissue sent for pathologic analysis
Fine-needle aspiration
Bone scan

PREFERRED RESPONSE: 1- Order a prostate-specific antigen (PSA) level

DISCUSSION

The radiograph and MR images show an osteoblastic lesion in the T9 and T8 vertebral bodies. In an older man, this finding most likely reveals metastatic prostate cancer. The first and least invasive diagnostic step is to order a PSA level. Gleave and associates found in a retrospective review of patients with prostate cancer that isolated levels of PSA lower than 10 to 20 micrograms per liter are rarely associated with bone metastasis. Vis and associates documented that 10-year prostate cancer survival in a screened population was higher than 60%, and in an unscreened population it was 24%. In a neurologically intact patient with no evidence of neural compression or instability, surgery is not indicated. Fine-needle aspiration may be performed, but the diagnostic yield in a blastic lesion is low. A bone scan may be indicated to complete the metastatic workup, but it will not aid in the diagnosis of tissue source.

CLINICAL SITUATION FOR QUESTIONS 26 THROUGH 29

Figures 26a and 26b are the MR images with gadolinium enhancement of a 40-year-old man who arrives at the emergency department with a 4-day history of fevers and severe back pain without radiation. He is normotensive at presentation with a heart rate of 86 beats per minute. Upon examination he is neurologically intact with normal sensory and motor function. He has a history of alcohol and cocaine abuse. His white blood cell (WBC) count is 12000 (reference range [rr], 4500-11000 /µL) and his C-reactive protein (CRP) level is 100 mg/L (rr, 0.08-3.1 mg/L)

Question 26 of 100

Based on this patient's history and examination, what is the best next step?

Order a confirmatory erythrocyte sedimentation rate (ESR)
Obtain blood cultures
Initiate empiric broad-spectrum antibiotics
Perform surgical decompression

PREFERRED RESPONSE: 2- Obtain blood cultures

Question 27 of 100

Blood cultures reveal methicillin-sensitive Staphylococcus aureus (MSSA). The patient's examination remains unchanged. In addition to outpatient serial laboratory studies and weekly observation for neurologic deterioration, which of the following is the most appropriate for nonoperative treatment?

Interventional radiology placement of an epidural drain
An 8-week course of intravenous (IV) vancomycin
An 8-week course of IV nafcillin
An 8-week course of oral amoxicillin

PREFERRED RESPONSE: 3- An 8-week course of IV nafcillin

Question 28 of 100

Clinical characteristics of patients who are ideal for a nonsurgical treatment trial (instead of surgery) include

absence of neurologic deficits and MSSA infection.
normal blood pressure and normal heart rate.
negative blood cultures, cocaine abuse
normal blood pressure and normal heart rate

PREFERRED RESPONSE: 1- absence of neurologic deficits and MSSA infection.

Question 29 of 100

What would be the advantage of surgery for the patient described in this scenario?

Shorter length of antibiotic therapy
Reduced mortality risk
Reduced risk for neurologic deterioration
Reduced risk for chronic pain

PREFERRED RESPONSE: 3- Reduced risk for neurologic deterioration

DISCUSSION

The MR image of the lumbar spine postgadolinium contrast shows a ring-enhancing fluid collection. Ring-enhancing lesions within the spinal canal on postgadolinium MR images are indicative of epidural abscess. It is important to obtain a culture-specific diagnosis to inform the choice of antibiotics and educate patients regarding the likelihood of failure for standalone antibiotic therapy. Infection with MSSA, age younger than 65 years, the absence of neurologic deficit, and lumbar abscess location are all factors that point toward a patient being a reasonable candidate for a trial of culture-specific IV antibiotics. In this case, nafcillin is a suitable treatment for MSSA. The antibiotic should be initiated and closely observed with serial labs (WBC, ESR, CRP, repeat blood cultures) to ensure that the patient responds appropriately to therapy and that neurologic deficits do not develop. In the setting of epidural abscess, surgery is performed to evacuate the abscess and reverse or prevent neurologic deterioration. In the current scenario in which sepsis is not an issue, scant high-quality evidence shows that surgical intervention influences risk for mortality or chronic pain following epidural abscess.

Question 30 of 100

Figures 30a through 30c are the radiograph and MR images of a 54-year-old woman who has severe leg pain with walking. Her treatment has included 12 weeks of

physical therapy, anti-inflammatory medications, and narcotic pain relievers, and she is interested in surgery. Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is recommended. When compared with open TLIF, MIS TLIF is associated with

shorter hospital stay.
lower rates of fusion.
higher complication rates.
worse long-term outcomes.

PREFERRED RESPONSE: 1- shorter hospital stay.

DISCUSSION

MIS TLIF involves a steep learning curve but is associated with similar longterm outcomes as open TLIF, arguably comparable or possibly lower complication rates, and equivalent fusion rates. The major distinguishing feature comparing open to minimally invasive surgery for this and other spinal diagnoses has been shorter hospital stays.

Question 31 of 100

An orthopaedic surgeon is counseling a patient regarding risk for complications following lumbar fusion via a direct lateral approach. Surgery at which level is most likely to injure the lumbosacral plexus?

1- L1-2

2- L2-3

3- L3-4

4- L4-5

PREFERRED RESPONSE: 4- L4-5

DISCUSSION

During the direct lateral approach, interbody fusion devices are inserted through a lateral window in the psoas muscle. To accomplish this, dilators and retractors are positioned at the posterior half of the disk space, and it must be noted that the lumbosacral plexus lies within the psoas muscle between the transverse process and vertebral body and departs distally at the medial edge of the psoas. Consequently, lateral interbody fusion poses risk for injury to the lumbosacral plexus. A cadaveric study demonstrated that the lumbosacral plexus progressively migrates from dorsal to ventral in the lumbar spine. Therefore, the plexus is most likely to be injured during an L4-L5 fusion because at this level the lumbosacral plexus is closest to the location at which dilators and retractors are placed.

A 2013 retrospective study by Le and associates followed 71 patients who underwent minimally invasive fusion via a lateral interbody approach. In this study, 54.9% (39/71) had immediate postsurgical ipsilateral iliopsoas or quadriceps weakness. Of these patients, the majority had resolution by 3 months (92.3%), and all had complete resolution by 2 years.

Question 32 of 100

Figure 32 shows the T2-weighted MR image through the L4-5 level of a 60-year-old man who has new-onset acute right lower-extremity pain and numbness and weakness in his right quadriceps muscle. The arrow in Figure 32 is pointing to which structure?

Lumbar synovial cyst
Dorsal root ganglion
Herniated nucleus pulposus
Ligamentum flavum

PREFERRED RESPONSE: 3- Herniated nucleus pulposus

DISCUSSION

The arrow is pointing to a structure of medium signal intensity that is equivalent to the nucleus pulposus on T2-weighted sequencing. This represents a foraminal disk herniation. A lumbar synovial cyst would display high-signal intensity on T2-weighted sequencing. Lumbar synovial cysts arise from the facet joints as a result of facet joint degeneration and may be a source of nerve root compression. The dorsal root ganglion is a collection of sensory nerve cell bodies and can be seen just dorsal and lateral to the disk herniation in Figure 32. The ligamentum flavum is located on the ventral

surface of the laminae and attaches between the laminae of adjacent vertebrae.

Question 33 of 100

One year after undergoing anterior cervical decompression and fusion, what percentage of patients still have dysphagia?

1- 10% to 15%

2- 30% to 35%

3- 50% to 55%

4- 70% to 75%

PREFERRED RESPONSE: 1- 10% to 15%

DISCUSSION

Dysphagia after anterior cervical diskectomy and fusion is a common, usually transient finding after anterior cervical approaches to the spine. While it has been reported to occur in up to 70% of patients 2 weeks following surgery, in most cases the symptoms quickly resolve. There is, however, a small subset of patients for whom symptoms of dysphagia will persist. Lee and associates prospectively studied the rate of dysphagia after anterior cervical diskectomy and fusion, reporting a 15% rate of dysphagia at 12 months, and 12% at 24 months. Phillips and associates analyzed the 2-year data from the PCM FDE clinical trial and found a 12.1% incidence of dysphagia in the ACDF arm.

Question 34 of 100

What is the most appropriate initial diagnostic imaging study for a patient with presumed diskogenic low-back pain?

MRI
Discography
CT discography
Radiography

PREFERRED RESPONSE: 4- Radiography

DISCUSSION

Radiography is the best initial study. Vacuum phenomenon may be found within the disk space. Other possible sources for back pain such as osteoporotic collapse, osteolytic collapse, and deformity also can be evaluated. The other tests may be beneficial and are more appropriate as later imaging options.

Question 35 of 100

Figure 35 is the sagittal MR image of a 56-year-old woman who has a 3-year history of severe back pain. Her pain is worse with flexion at the lumbosacral junction and is relieved with extension. She denies any pain in her lower extremities and has no symptoms of neurogenic claudication. Which mediators play roles in the pathogenesis of this condition?

Transforming growth factor-beta (TGF-ß), bone morphogenetic protein-2 (BMP-2), latent membrane protein 1
Tissue inhibitor of matrix metallo-proteinase-1 (MMP-1), growth and development factor-5, noggin
Gremlin, MMP, biglycan
Tumor necrosis factor-alpha (TNF-a), Interleukin-1 (IL-1), MMP

PREFERRED RESPONSE: 4- Tumor necrosis factor-alpha (TNF-a), Interleukin-1 (IL-1), MMP

DISCUSSION

The patient has degenerative disk disease with diskogenic back pain. Several studies in both humans and animals have implicated TNF-a, IL-1, and MMP in extracellular matrix degeneration and disk degradation. TGF-ß, BMP-2, latent membrane protein 1, and growth and development factor-5 are all postulated to play anabolic roles in the intervertebral disk. Biglycan is a small leucine-rich proteoglycan that regulates extracellular matrix assembly within the disk. Noggin and gremlin are biochemical factors not involved in disk degradation.

Question 36 of 100

A 45-year-old woman with a history of rheumatoid arthritis has C1-C2 instability with neurologic deterioration. Her posterior atlanto-dens interval is 10 mm. Which fixation technique will be the most biomechanically sound to facilitate fusion across the atlanto-axial junction?

Gallie fusion
Use of C1-C2 transarticular screws
Brooks fusion
Onlay grafting with a halo vest

PREFERRED RESPONSE: 2- Use of C1-C2 transarticular screws

DISCUSSION

C1-C2 transarticular screw fixation is 10-fold stiffer than wiring constructs, particularly in rotation; eliminates the need for postsurgical halo use; and is associated with reported fusion rates to a maximum of 100% for bilateral screws and 95% for unilateral fixation. All of the other fusion techniques mentioned are associated with a pseudarthrosis rate of at least 30%.

CLINICAL SITUATION FOR QUESTIONS 37 THROUGH 43

Figure 37 is the lateral radiograph of a 71-year-old woman who has pain with ambulation that improves when she sits down. She had similar symptoms 2 years earlier when she underwent an L3-L5 posterior spinal fusion. Upon examination she has good range of hip and knee motion, 5/5 motor function, and normal sensation of her lower extremities. She has negative bilateral straight-leg raise findings and her knees slightly flex to stand upright

Question 37 of 100

What is the most likely diagnosis considering this patient's history and examination?

Metastatic disease of the spine
Neurogenic claudication
Degenerative joint disease of the hips
Degenerative scoliosis

PREFERRED RESPONSE: 2- Neurogenic claudication

Question 38 of 100

In addition to MR imaging, what is the most appropriate additional radiographic study at this time?

Mechanical axis of the lower extremities
Long-standing radiograph of the entire spine
Nuclear medicine: triple-phase bone scan
Hyperextension radiograph of the lumbar spine

PREFERRED RESPONSE: 2- Long-standing radiograph of the entire spine

Question 39 of 100

In addition to her planned primary procedure, how can the surgeon best improve this patient's lumbar lordosis?

Placement of bilateral iliac screws
Use of an interbody strut at L5-S1
Extension of instrumentation to T11
Extension lumbosacral orthosis

PREFERRED RESPONSE: 2- Use of an interbody strut at L5-S1

Question 40 of 100

The patient is treated by another physician and undergoes the procedure shown in Figures 40a and 40b. She currently cannot stand upright. Spinopelvic measurements reveal her pelvic incidence to be 85 degrees and pelvic tilt to be 40 degrees. Her lordosis from T12-S1 is 35 degrees. Which additional surgical procedure should be considered?

40A

Single-level pedicle subtraction osteotomy
Single-level Smith-Petersen osteotomy
Instrumentation removal
Percutaneous fusion of the sacroiliac joints

PREFERRED RESPONSE: 1- Single-level pedicle subtraction osteotomy

Question 41 of 100

The patient's postsurgical radiographs reveal a sagittal vertical axis of +8 cm. In addition to the usual issues encountered during the early postsurgical period, what should the surgeon be most concerned about?

Instrumentation-related pain
Broken rod
Sacroiliac dissociation
Proximal junctional failure

PREFERRED RESPONSE: 4- Proximal junctional failure

Question 42 of 100

Bearing in mind her current condition as shown in Figures 40a and 40b, the surgeon should inform the patient and family that if she is to stand erect, she

needs further spinal extensor strengthening.
will need to wear a spinal brace indefinitely.
will need another spinal surgery.
will need a spinal cord stimulator.

PREFERRED RESPONSE: 3- will need another spinal surgery.

Question 43 of 100

If additional posterior spinal surgery is performed to allow the patient to stand erect, the surgeon will need to advise the family about the risks of the procedure. In addition to risk for neurologic injury, what is the most likely complication?

Substantial blood loss
Cerebral vascular accident
Degeneration of sacroiliac joints
Cervical spine stenosis

PREFERRED RESPONSE: 1- Substantial blood loss

DISCUSSION

This case starts as standard degenerative spondylolisthesis but develops into a sagittal imbalance problem necessitating a major spinal procedure including

a pedicle subtraction osteotomy and extended posterior spinal instrumentation. Initially the patient had an L3-L5 posterior spinal fusion with a laminectomy and interbody fusion for an L4-L5 stenosis and degenerative spondylolisthesis. Two years after this procedure she is having difficult ambulation that improves with sitting. These symptoms are typical for neurogenic claudication associated with spinal stenosis. Adjacent segment degeneration leading to spinal stenosis is a common late complication associated with lumbar instrumented fusions, particularly in older patients. Figure 40b shows the adjacent segment degeneration at L5-S1 with the development of a degenerative spondylolisthesis. Degenerative spondylolisthesis is a radiographic sign of substantial degeneration of a disk space and is often associated with spinal stenosis. The primary procedure typically planned to address a degenerative spondylolisthesis is a laminectomy. An adjacent-level degenerative spondylolisthesis is typically instrumented and fused to the previous fusion construct.

The degeneration of the adjacent disk is also associated with a loss of disk height. A concern in this patient is the development of kyphosis at the L5-S1 disk space. Kyphosis at the lumbosacral junction can lead to sagittal imbalance issues. Spinal surgeons need to be aware of spinopelvic measurements to help prevent sagittal imbalance and proximal junctional failures. Improving the lumbar lordosis in this patient would necessitate restoration of the disk height at L5-S1. This can be accomplished with an interbody strut device placed either anteriorly or posteriorly via a posterolateral interbody approach at the time of the laminectomy.

This patient has undergone a posterior extension of her previous fusion without the addition of an interbody strut device. She now has further sagittal imbalance issues and an inability to stand erect without flexing her knees. This is a typical compensation posture that patients with significant sagittal imbalance acquire when trying to stand upright. Patients with sagittal imbalance are at increased risk for proximal junctional kyphosis or a more acute complication of proximal junctional failure.

The sagittal vertical axis is a plumb line dropped from C7 and should fall behind the hip joints and within 4 to 5 cm of the posterior corner of S1 (an easily identifiable radiographic marker). Pelvic incidence is a constant that is unique to each patient's spinopelvic anatomy. Pelvic incidence typically is within 10 degrees of the lumbar lordosis in an upright adult. Pelvic tilt (PT), on the other hand, can vary based on a patient's stance. PT is an indicator of the amount of compensation a patient has developed by retroverting their pelvis to stand upright. In an upright patient who is not compensating for loss of spinal sagittal alignment, the PT should be less than 20 degrees. In this case, the patient has a high PT and a significant lumbar lordosis/pelvic incidence mismatch with a significant positive sagittal imbalance (sagittal vertical axis of +8 cm). These are all indicators that a major spinal alignment procedure will be required to rebalance the spine. The use of posterior

osteotomies, such as a pedicle subtraction osteotomy, will be required if spinal realignment is planned. Pedicle subtraction osteotomies are considered 3-column osteotomies that remove the entire lamina, the facets, the pedicles (the posterior column), the underlying posterior vertebral wall and posterior vertebral body (middle column), and the underlying anterior vertebral body (anterior column) in a wedge fashion. Three-column osteotomies are associated with increased risk for neurologic injury and substantial blood loss. A Smith-Petersen osteotomy is a single-column posterior osteotomy that can provide a lesser amount of sagittal plane correction than pedicle subtraction osteotomy. A single-level Smith-Petersen osteotomy likely will not provide enough correction in this case.

Question 44 of 100

A 78-year-old athletic woman has a history of severe back pain without antecedent trauma. She was in the emergency department 2 days ago with a T12 compression fracture. A dual x-ray absorptiometry (DEXA) scan performed earlier this year revealed a T-score of -2.8. Her condition may be attributable to

translocation of chromosomes X and 18.
variant of the EXT1 gene.
polymorphism of p53.
polymorphism of the COL1A1 gene.

PREFERRED RESPONSE: 4- polymorphism of the COL1A1 gene.

DISCUSSION

The diagnosis is severe osteoporosis because this patient's T-score is lower than -2.5 on DEXA scan and her fragility fracture involves the T12 vertebra. Osteoporosis may be associated with polymorphisms of the COL1A1 gene. EXT1 is associated with multiple hereditary exostoses, and translocation X:18 is associated with synovial sarcoma. The gene p53 is associated with Li-Fraumeni syndrome and osteosarcoma.

Question 45 of 100

Figures 45a and 45b are the CT and MR spine images of an 82-year-old man who has a history of ankylosing spondylitis falls onto his back. He has no

neurologic deficits upon examination in the emergency department. What is the most appropriate next step?

Obtain upright radiographs
Thoracolumbar orthosis
Posterior stabilization and fusion
Laminectomy

PREFERRED RESPONSE: 3- Posterior stabilization and fusion

DISCUSSION

Spinal fractures in patients with ankylosing spondylitis are unstable and generally necessitate surgical intervention. In a patient with a spinal fracture in the setting of ankylosing spondylitis, posterior instrumented fusion is an appropriate surgical procedure. Treatment with a thoracolumbar orthosis is not an option for patients with extension distraction injuries in the setting of an ankylosed spine because of risk for displacement. Similarly, simply checking upright radiographs is generally not advocated. Laminectomy alone is inappropriate for this patient because there is no cord compression and neurologic symptoms are absent. Stabilization is the treatment goal.

Question 46 of 100

A 17-year-old girl is involved in a motor vehicle collision and sustains the injury shown in Figures 46a through 46c. She is neurologically intact in her bilateral lower extremities. Definitive treatment should consist of

anterior reduction, stabilization, and fusion at L1-2.
anterior reduction, stabilization, and fusion at T12-L3.
posterior reduction, stabilization, and fusion at L1-2.
posterior reduction, stabilization, and fusion at T12-L4.

PREFERRED RESPONSE: 4- posterior reduction, stabilization, and fusion at T12-L4.

DISCUSSION

The figures reveal a fracture-dislocation at L1-2. Proper treatment consists of posterior reduction, stabilization, and fusion 2 levels above and below the level of injury. Short-segment stabilization schemes do not stabilize the injury properly, and longer-segment constructs are not necessary. Anterior treatment is not indicated in fracture-dislocations.

Question 47 of 100

What is the advantage of percutaneous pedicle screw fixation over open instrumentation and fusion for a thoracolumbar burst fracture without neurologic deficit?

Better clinical outcomes
Less blood loss
Less pseudarthrosis risk
Lower revision surgery rate

PREFERRED RESPONSE: 2- Less blood loss

DISCUSSION

A prospective randomized study on short-segment treatment of burst fractures with and without fusion demonstrated similar outcomes at 5 years with lower blood loss in the nonfusion group. There is by definition no fusion performed with percutaneous stabilization, so patients often develop hardware failure. Some surgeons routinely remove instrumentation following percutaneous stabilization, thus revision surgery is common. Clinical outcomes are not improved compared to open methods.

RESPONSES FOR QUESTIONS 48 THROUGH 50

Fracture displacement or subluxation leading to neurologic injury
Symptomatic epidural hematoma
Sepsis and death
Permanent nerve root injury and neurologic deficit
Loss of bowel or bladder control
Spinal cord injury

Select the complication listed above that most commonly is associated with the appropriate clinical scenario described below.

Question 48 of 100

A 25-year-old man with a large central disk herniation at L4-5 with normal motor strength, perineal numbness, and difficulty urinating for 36 hours

Fracture displacement or subluxation leading to neurologic injury
Symptomatic epidural hematoma
Sepsis and death
Permanent nerve root injury and neurologic deficit
Loss of bowel or bladder control
Spinal cord injury

PREFERRED RESPONSE: 5- Loss of bowel or bladder control

Question 49 of 100

A 65-year-old man with ankylosing spondylitis has a fall from a standing height. He previously had minimal range of motion in his cervical spine, but now notices he is better able to extend his head. He is seen in the emergency department and released with a soft collar for use as needed.

Fracture displacement or subluxation leading to neurologic injury
Symptomatic epidural hematoma
Sepsis and death
Permanent nerve root injury and neurologic deficit
Loss of bowel or bladder control
Spinal cord injury

PREFERRED RESPONSE: 1- Fracture displacement or subluxation leading to neurologic injury

Question 50 of 100

A 74-year-old man with ankylosing spondylitis falls off a step stool and now has a minimally displaced T10-T11 extension-type fracture. He is initially treated with percutaneous pedicle screw fixation from T8-L1 and has good pain relief. The next day, however, he experiences increased back pain and loss of strength in his lower extremities.

Fracture displacement or subluxation leading to neurologic injury
Symptomatic epidural hematoma
Sepsis and death
Permanent nerve root injury and neurologic deficit
Loss of bowel or bladder control
Spinal cord injury

PREFERRED RESPONSE: 2- Symptomatic epidural hematoma

DISCUSSION

Cauda equina syndrome, typically the result of severe central canal stenosis in the lower lumbar region, often is caused by a large central disk herniation. Symptoms include severe back or leg pain, perineal numbness, possible motor weakness, and initial urinary retention followed by an overflow incontinence. When bowel or bladder deficits are present, this is considered a surgical emergency because successful recovery is most likely if decompression occurs within the first 48 hours.

Ankylosing spondylitis can lead to progressive autofusion of the vertebrae and significant limitation in motion. Any sudden improvement in motion should be considered a fracture until proven otherwise. These fractures are commonly missed when using plain radiographs or even CT scan because minimal or no displacement often is noted. MR imaging can be useful to identify edema at

the fracture site. These fractures are typically very unstable and necessitate surgery to avoid displacement and potential neurologic injury.

Some fractures associated with ankylosing spondylitis can be effectively treated with percutaneous pedicle screw fixation. However, because of the highly vascular nature of some of these fractures, they pose risk for an epidural hematoma, potential neurologic deficit, and emergent decompression.

Question 51 of 100

What is the chief mechanism of action of parathyroid hormone (PTH) in the treatment of patients with osteoporosis?

Reduces resorptive activity of osteoclasts
Inhibits receptor activator of nuclear factor kappa-B ligand
Stimulates osteoblastic bone formation
Acts as a selective estrogen modulator

PREFERRED RESPONSE: 3- Stimulates osteoblastic bone formation

DISCUSSION

Recombinant human PTH benefits patients with osteoporosis by stimulating osteoblastic bone formation and reducing osteoblastic apoptosis. Treatment reduces vertebral fractures by 65%. PTH analogs act similarly and reduce vertebral fractures by 47%. Bisphosphonates reduce the resorptive activity of

osteoclasts and cause a dissociation of bone formation and resorption that favors bone formation and reduce vertebral fractures by 50% to 70%. Selective estrogen receptor modulators inhibit bone resorption and reduce vertebral fractures by 35%. Humanized monoclonal antibodies inhibit osteoclast formation and reduce vertebral fractures by 68%.

Question 52 of 100

Figures 52a and 52b are the radiographs of a patient who was involved in a motor vehicle collision. He was wearing his seat belt and is now complaining of midthoracic back pain. Radiographs in the emergency department do not reveal a fracture. What is the most appropriate next step?

Nonsteroidal medication and follow up as needed
Repeat radiographs in 1 week
MR imaging of the thoracic spine
Flexion-extension radiographs

PREFERRED RESPONSE: 3- MR imaging of the thoracic spine

DISCUSSION

Ankylosing spinal disorders, including ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis, are conditions that make the spine rigid and at risk for 3-column unstable fractures. Spinal fractures in these patients pose high risk for complications and death and patients should be counseled and observed closely. Mortality strongly correlates with older age and increased number of comorbidities.

These spine fractures often are not seen at the time of initial evaluation, and a delay in diagnosis can occur in up to 19% of cases. This is particularly common in the setting of non- or minimally displaced fractures following minor injuries. A delayed diagnosis can lead to displacement of a previously nondisplaced fracture that can incur a high neurologic injury risk. Advanced imaging with a CT scan or MRI should be obtained for patients with ankylosing spinal disorders even when minor injuries occur. Although bracing and observation can be used, posterior multilevel spinal instrumentation is typically required to obtain adequate spinal stabilization.

The radiographs show an osteopenic ankylosed thoracic spine; the anteroposterior radiograph clearly shows fusion of the sacroiliac joints. Recognition of these radiographic findings is important when evaluating patients after an injury.

Question 53 of 100

A 70-year-old otherwise healthy woman is undergoing correction of thoracic kyphosis with spinal cord compression via a posterior approach. She receives an inhaled anesthetic, her mean arterial pressure is 93 mm Hg, and her core temperature is 37.2°C. Her spinal cord is being monitored with somatosensory-evoked potentials and transcranial motor-evoked potentials. She has very low amplitude and increased latency as detected by neurophysiologic monitoring. Which action should be taken?

A Stagnara wake-up test should be performed immediately.
The patient's mean arterial pressure should be increased immediately.
The anesthesia team should use propofol instead of isoflurane.
The patient's core temperature should be decreased to 35°C.

PREFERRED RESPONSE: 3- The anesthesia team should use propofol instead of isoflurane.

DISCUSSION

The use of halogenated inhaled anesthetic agents has been shown to abrogate the signals detected during neurophysiologic monitoring. Intravenous agents such as propofol should be used in favor of inhaled agents such as isoflurane and nitrous oxide. Neurophysiologic signals also can be dampened when hypotension and hypothermia are issues. In this case, the patient's mean arterial pressure and body temperature are within the range at which spinal cord blood flow and neurophysiologic monitoring may be optimized. A Stagnara wake-up test may be useful, but it poses risk. If there is another explanation for the patient's lack of signal, this test is not necessary.

Question 54 of 100

A B

Figures 54a and 54b are the radiographs of a 21-year-old man who has a long history of thoracic back pain. His lumbar spine is asymptomatic. He has failed prolonged nonsurgical treatment. Surgical correction should consist of

anterior release and fusion at T4-10.
posterior instrumentation and fusion at T9-L5.
posterior instrumentation and fusion at T2-L2.
posterior instrumentation and fusion at T6-pelvis.

PREFERRED RESPONSE: 3- posterior instrumentation and fusion at T2-L2.

DISCUSSION

When planning surgical intervention for Scheuermann kyphosis, it is imperative that the instrumentation and fusion extend across the entirety of the deformity. Distally, this means extending across the first lordotic disk space. In this scenario, this disk is the L1-L2 disk, which means the fusion needs to extend to L2. Shorter and longer fusions are not necessary or appropriate.

CLINICAL SITUATION FOR QUESTIONS 55 THROUGH 59

A 60-year-old woman has severe neck and back pain. She is relatively healthy but has diabetes and neuropathy involving her lower extremities. Her body mass index is 38. She has a history of spinal fusion performed by your colleague 3 years ago. At that time, she was treated for degenerative scoliosis of the lumbar spine with concomitant spinal stenosis. A 360-degree fusion was performed from L4-S1 with a posterior decompression from L2-S1 and a posterior instrumented fusion from T3 to the pelvis. On examination, she has reproducible pain and a visible kyphosis in the periscapular region. Neurologic examination findings are within normal limits, with the exception of lower-extremity dysesthesias related to her neuropathy. The patient states that she has been having progressive difficulty dressing herself and taking care of her apartment for several months. Plain radiographs and a standing scoliosis series demonstrate a solid fusion from the sacrum to T3 without evidence of hardware failure. There is focal collapse of the T2-T3 disk space and a proximal kyphosis involving the T2 vertebrae that is indicative of disk and ligamentous failure.

Question 55 of 100

The patient asks why the proximal kyphosis occurred. You indicate that she has several risk factors for this condition, including

her age, fusion to the sacrum, and upper instrumented vertebra at T3.
her age, 360-degree fusion, and obesity.
diabetes, history of neuropathy, and pelvic instrumentation.
upper instrumented vertebra at T3, obesity, and diabetes.

PREFERRED RESPONSE: 1- her age, fusion to the sacrum, and upper instrumented vertebra at T3.

Question 56 of 100

Considering her current symptoms, history, and examination findings, you believe that the most efficacious means with which to address this patient's junctional kyphosis is

cervico-thoracic-lumbosacral orthosis to immobilize the kyphosed segment.
removal of the posterior instrumentation because she has had a successful fusion.
anteroposterior instrumented fusion at T2-3 to address the collapsed interspace.
revision posterior instrumentation with extension of the fusion to T1 to span the area of junctional kyphosis.

PREFERRED RESPONSE: 4- revision posterior instrumentation with extension of the fusion to T1 to span the area of junctional kyphosis.

Question 57 of 100

What are this patient's risk factors for postsurgical infection?

Presence of posterior spinal instrumentation
Anterior approach performed during the index procedure
Diabetes and obesity
Surgery performed in the thoracic spine

PREFERRED RESPONSE: 3- Diabetes and obesity

Question 58 of 100

Which complication is most frequently encountered after revision surgery to treat junctional kyphosis?

Deep surgical-site infection
Pseudoarthrosis
Neurological injury
Adjacent segment degeneration

PREFERRED RESPONSE: 4- Adjacent segment degeneration

Question 59 of 100

During the revision surgical procedure, thoracic pedicle screws are placed. Following placement, triggered electromyography (EMG) is performed by stimulating the pedicle screw heads. During testing the right T2 pedicle screw head returns a threshold of 2 mA. What does this reading indicate?

The right T2 pedicle screw is well seated within the pedicle.
The right T2 pedicle screw has breached the pedicle wall and has violated the costovertebral junction.
There is a breach in the right T2 pedicle wall, but the screw is not in contact with a neural structure.
There is a breach in the right T2 pedicle and the screw is in contact with a neural structure.

PREFERRED RESPONSE: 4- There is a breach in the right T2 pedicle and the screw is in contact with a neural structure.

DISCUSSION

This patient has developed a proximal junctional kyphosis following a long posterior fusion performed for treatment of degenerative lumbar scoliosis. Risk factors for proximal junctional kyphosis in the setting of instrumented fusions performed for degenerative scoliosis include advanced age, 360-

degree fusions, extension of fusion constructs to the sacrum, and upper instrumented vertebrae at the level of T1-3. The patient's junctional kyphosis is attributable to failure of the disk and ligamentous structures at T2-3 and would be graded as type I using the classification system of Yagi and associates. Most symptomatic proximal junctional kyphoses are treated with posterior extension of the fusion construct to a more proximal level spanning the kyphosed region. The use of orthoses or simple removal of instrumentation is unlikely to substantively impact symptoms or address the proximal kyphosis. Diabetes and obesity are known factors that increase risk for postsurgical infection following a spine fusion procedure. The most frequent complication following revision surgery for proximal junctional kyphosis, however, is the need for further surgery. In the study by Yagi and associates, 48% of patients who underwent revision surgery for proximal kyphosis developed further adjacent segment degeneration. In the proximal thoracic spine, where the pedicle may be narrow, triggered EMG testing of inserted pedicle screws may be used to assess for violation of the pedicle wall during insertion. In the setting of triggered EMG, thresholds exceeding 10 mA indicate a well-placed pedicle screw. Thresholds lower than 4 mA to 6 mA indicate that a screw is directly contacting a neural structure. Thresholds between 9 mA and 10 mA suggest that a breach of the pedicle may be present, but the screw is not contacting a neural structure.

Question 60 of 100

Figures 60a and 60b are the postmyelography CT images of a 62-year-old man who has had low-back and bilateral lower-extremity pain. His pain began approximately 1 year ago and there was no precipitating event. The location of the pain is in the lower lumbar region in the midline and it radiates into the buttocks and thighs bilaterally. The pain is exacerbated by standing and walking and relieved by forward spine flexion. He reports no pain while sitting or lying supine. Upright radiographs demonstrate 4 mm of anterolisthesis of L4 on L5. What is the most appropriate surgical procedure?

Microdiskectomy
Posterior decompression
Posterior decompression and fusion
Anterior lumbar interbody fusion

PREFERRED RESPONSE: 3- Posterior decompression and fusion

DISCUSSION

This patient radiographically has L4-5 degenerative stenosis and a low-grade spondylolisthesis. The axial images demonstrate a gap in the facet joint, more on the left than the right, which is highly suggestive of dynamic instability. Thus, this patient would most benefit from a laminectomy and fusion of L4-5. A microdiskectomy would not be helpful as this patient does not have a disk herniation. Patients undergoing posterior decompression alone experience an unacceptably high rate of recurrent stenosis and/or progression of spondylolisthesis. Early studies demonstrated that adding an intertransverse process fusion to posterior decompression significantly improved clinical outcomes. Anterior interbody fusion likely will not decompress the spinal canal sufficiently, though there is some thought that indirect decompression can be effective in some cases.

Question 61 of 100

A 78-year-old man with ankylosing spondylitis sustains a minor fall. Shortly afterward he experiences sudden worsening of his chronic back pain and is brought to the emergency department by his caregiver. Radiographs and a CT scan of the spine do not show a clear fracture. What is the most appropriate next step?

Nonsteroidal anti-inflammatory drugs
MRI of the spine
CT myelography
Flexion-extension plain films

PREFERRED RESPONSE: 2- MRI of the spine

DISCUSSION

Patients with ankylosing spondylitis are at high risk for occult fractures after low-energy injuries. Although radiographs and a CT scan do not demonstrate a spinal fracture in this patient, high risk for an unstable occult fracture necessitates further imaging with MRI to ensure that no fractures are missed. Although a CT scan is typically the primary imaging modality for workup of spine injuries in similar patients, CT and MRI complement each other and each detects fractures that are missed using the other modality. A CT myelogram might detect cord or root compression but would not aid in the diagnosis of an occult fracture. Nonsteroidal anti-inflammatory drugs are first-line treatment for idiopathic low-back pain. In a patient with ankylosing spondylitis at high risk for fracture, further workup is needed to rule out an occult fracture. Flexion and extension radiographs of the spine are inferior to MRI for evaluating occult fractures and ligamentous injuries. The primary concern for this patient remains an unstable spinal fracture, which necessitates an MRI of the spine before initiating a workup for other possible causes of his back pain.

Question 62 of 100

Figures 62a through 62c are the MR images and CT scan of a 65-year-old man with a history of diabetes mellitus, hypertension, and smoking. He has a 6-week history of increasing midback pain, lower extremity pain, and weakness. What is the most likely diagnosis, and how should this diagnosis be confirmed?

Thoracic tumor; CT-guided biopsy
Thoracic tumor; 3-phase bone scan
Thoracic discitis and osteomyelitis; CT-guided biopsy
Thoracic discitis and osteomyelitis; tagged white blood cell scan

PREFERRED RESPONSE: 1- Thoracic tumor; CT-guided biopsy

DISCUSSION

The sagittal T2-weighted and axial T2-weighted images show a lesion within the T8 vertebral body that involves the posterior elements. There is an associated epidural component that results in compression of the spinal cord. The sagittal reconstructed CT image shows a lytic lesion within the T8 vertebral body. This pattern of vertebral body involvement with preservation

of the adjacent disks and endplates in a 65-year-old patient is most compatible with a diagnosis of a tumor. The most likely tumor is a metastatic lesion. A CT-guided biopsy will confirm this diagnosis. Although thoracic tuberculosis does not typically cross the disk space, the lack of an anterior soft-tissue component decreases the likelihood of this diagnosis.

Question 63 of 100

Misplaced pedicle screws are the most common complication associated with pedicle screw instrumentation. Many physicians use continuous electromyography (EMG) monitoring and direct stimulation of the screw to produce a peripheral EMG response. Which EMG stimulation minimum threshold indicates an accurately placed pedicle screw?

Higher than 20 mA
Higher than 15 mA
Higher than 10 mA
5 to 10 mA

PREFERRED RESPONSE: 1- Higher than 20 mA

DISCUSSION

A threshold of 15 mA or higher provides 98% confidence in accuracy of pedicle screw placement. If the EMG stimulation threshold is lower than 4 mA to 6 mA, the screw likely is in contact with the nerve root or dura. A threshold lower than 8 mA to 10 mA is associated with a breach in the pedicle cortex.

Question 64 of 100

What is the most significant benefit of percutaneous transforaminal lumbar interbody fusion (TLIF) vs open posterior lumbar interbody fusion (PLIF)?

Preservation of the paraspinal muscle sleeve
Higher fusion rate
More measurable intraoperative blood loss
Improved ability to evacuate the disk space

PREFERRED RESPONSE: 1- Preservation of the paraspinal muscle sleeve

DISCUSSION

Humphreys and associates in a retrospective review of TLIF vs PLIF found fusion rates, surgical time, and length of hospital stay were similar with both procedures. The only benefits associated with TLIF were less blood loss and preservation of the paraspinal muscle sleeve. Manos and associates in a cadaver study found no difference in the volume of disk material evacuated or the area of endplate exposed in either procedure.

Question 65 of 100

Figure 65 is the lumbar spine MR image of a 63-year-old woman who has a 3-year history of increasingly bothersome back pain and bilateral buttock and leg pain. She has performed 6 weeks of physical therapy, received epidural injections, and experienced some good short-term results, but her leg pain continues to worsen. What is the most appropriate course of treatment?

Anterior lumbar interbody fusion L4-5
L4-5 hemilaminotomy and diskectomy
Lumbar laminectomy L4-L5 posterior fusion
Lumbar laminectomy at L4-5

PREFERRED RESPONSE: 3- Lumbar laminectomy L4-L5 posterior fusion

DISCUSSION

This patient has symptoms consistent with neurogenic claudication secondary to lumbar spinal stenosis and degenerative spondylolisthesis. Her symptoms are chronic and she has undergone an appropriate course of nonsurgical care. Nevertheless, her symptoms are worsening and surgical intervention is a

reasonable consideration. Studies have shown that patients with lumbar spinal stenosis with associated degenerative spondylolisthesis benefit most from decompression of the neural elements that are stenotic and subsequent fusion across the degenerative slip. Anterior lumbar interbody fusion likely will not address stenosis at the level of the slip and may not result in adequate neurologic decompression. Partial laminotomy and diskectomy likely will not provide adequate neural decompression because these procedures would only address unilateral compression and this patient has bilateral issues. Lumbar laminectomy without fusion could be performed but has been associated with results inferior to lumbar laminectomy with fusion when addressing stenosis with spondylolisthesis.

RESPONSES FOR QUESTIONS 66 THROUGH 69

Deep surgical-site infection
Adjacent segment degeneration
Pressure ulcers
Iatrogenic neurologic injury
Incidental durotomy
Hardware failure

Match the frequently encountered complication listed above with the appropriate clinical scenario below.

Question 66 of 100

A 63-year-old woman who was treated with decompression and instrumented L4-L5 interbody fusion for degenerative spondylolisthesis demonstrates solid fusion on radiographs.

Deep surgical-site infection
Adjacent segment degeneration
Pressure ulcers
Iatrogenic neurologic injury
Incidental durotomy
Hardware failure

PREFERRED RESPONSE: 2- Adjacent segment degeneration

Question 67 of 100

A 28-year-old obtunded man with a T12 burst fracture is treated in a thoracolumbosacral orthosis.

Deep surgical-site infection
Adjacent segment degeneration
Pressure ulcers
Iatrogenic neurologic injury
Incidental durotomy
Hardware failure

PREFERRED RESPONSE: 3- Pressure ulcers

Question 68 of 100

A 42-year-old man with an L1 burst fracture, no neurologic deficit, and evidence of disruption of the posterior ligamentous complex as observed on MRI is treated with percutaneous stabilization without fusion.

Deep surgical-site infection
Adjacent segment degeneration
Pressure ulcers
Iatrogenic neurologic injury
Incidental durotomy
Hardware failure

PREFERRED RESPONSE: 6- Hardware failure

Question 69 of 100

A 46-year-old man with a sacral chordoma is treated with sacrectomy.

Deep surgical-site infection
Adjacent segment degeneration
Pressure ulcers
Iatrogenic neurologic injury
Incidental durotomy
Hardware failure

PREFERRED RESPONSE: 1- Deep surgical-site infection

DISCUSSION

Complications frequently occur following treatment for spinal disorders. Postsurgical morbidity may range from minor complications such as urinary tract infection to death. Wound infections are among the most commonly encountered complications following any surgical intervention; however, their incidence after spine surgery has been reported to be in the range of only 1% to 6%. Meanwhile, risk for adjacent segment degeneration, particularly following a fusion procedure performed with an interbody device, has been documented as high as 30%. Pressure ulcers can occur when spinal injuries are treated with rigid orthoses, especially in individuals who are immobile. Risk for pressure sores and decubiti is further elevated in patients who are obtunded and cannot communicate regarding pain levels and their need to mobilize. Hardware failure may occur following any instrumented spine procedure, but risk for this complication is elevated in the event of pseudarthrosis or in settings in which no fusion is performed.

In the recent work of Lee and associates, hardware failure was the only complication encountered among patients who were treated with percutaneous stabilization without fusion for thoracolumbar burst fractures. Similarly, iatrogenic neurologic injury may transpire in the setting of any spinal intervention (its incidence is rare). For example, in a large cohort of

more than 10000 patients undergoing surgical treatment for spondylolisthesis, acute neurologic injury was reported in only 0.8% of cases. Postsurgical wound infection, although relatively rare in cases of elective spine surgery, is common following large tumor resection such as sacrectomy performed for treatment of chordomas.

Question 70 of 100

An awake and alert patient with neck pain arrives at the emergency department after an automobile crash. Upon examination he is weak in the left deltoid and biceps muscles (3/5 strength). CT scans performed 2 hours after admission are shown in Figures 70a and 70b. His weakness deteriorates

to 1/5 strength in the upper and lower extremities. What is the most appropriate treatment?

Immediate closed reduction in the intensive care unit while the patient is awake
Posterior spinal laminectomy and fusion with instrumentation
Anterior cervical diskectomy, corpectomy, and plating
High-dose methylprednisolone

PREFERRED RESPONSE: 1- Immediate closed reduction in the intensive care unit while the patient is awake

DISCUSSION

Facet subluxation reduction may be performed in awake patients. Posterior spinal laminectomy and fusion can result in worsening neurologic status and is not recommended in this setting. Generally, corpectomy in the setting of facet subluxation is not recommended because it does not facilitate reduction or fully alleviate spinal cord compression. High-dose steroid use is not supported by current literature.

Question 71 of 100

Pain emanating from the sacroiliac (SI) joint is best identified by which of the following maneuvers?

Reproduction of pain with the Gaenslen test
Reproduction of pain with the SI joint compression test
Presence of bone marrow edema on short tau inversion recovery sequence of MR images.
More than 75% pain reduction following fluoroscopically guided SI joint injection.

PREFERRED RESPONSE: 4- More than 75% pain reduction following fluoroscopically guided SI joint injection.

DISCUSSION

Though no gold standard exists, a reduction of concordant pain by at least 75 to 80% following an intra-articular, image-guided anesthetic injection is considered to be the most reliable method of identifying the SI joint as the cause of a patient's pain. Although provocation tests including the Gaenslen test, the compression test, thigh thrust, and Yeoman test are commonly used and can be helpful in diagnosing non-specific SI joint pain, individually they are not as reliable as the response to a diagnostic, anesthetic injection. Of note, the combination of all 4 manuevers has proven to be more useful than any one individual test. An MRI of the SI joint showing bony erosion and bone marrow edema suggests inflammatory arthritis and may not necessarily be associated with pain.

CLINICAL SITUATION FOR QUESTION 72 THROUGH 75

Figures 72a through 72c are the sagittal CT scan and thoracic MR images of a 52-year-old woman with a history of pancreatic neuroendocrine tumor who has severe upper thoracic back pain despite receiving aggressive oral pain treatment. She has metastases in her liver, adrenal glands, and abdominal mesentery. The thoracic disease has been treated with conventional radiation. She continues to work her part-time job without experiencing signs or symptoms of myelopathy.

A B

Question 72 of 100

What is the best next step in managing her pain?

Additional conventional radiation
En bloc spondylectomy
Palliative spinal cord decompression and stabilization
Epidural steroid injection

PREFERRED RESPONSE: 3- Palliative spinal cord decompression and stabilization

Question 73 of 100

What is the most appropriate systemic therapy for this patient in the short term?

Bisphosphonate therapy
Monoclonal antibody against receptor activator of nuclear factor kappa beta ligand
Doxorubicin
Dexamethasone

PREFERRED RESPONSE: 4- Dexamethasone

Question 74 of 100

If surgery is chosen, what is the optimum procedure?

Transthoracic corpectomy followed by posterior instrumentation
Percutaneous pedicle screw stabilization
Costotransversectomy with posterior instrumentation
Posterior total en bloc spondylectomy

PREFERRED RESPONSE: 3- Costotransversectomy with posterior instrumentation

Question 75 of 100

What is the goal of surgical treatment in this scenario?

To cure cancer
To prolong life
To relieve pain
To reverse neurologic symptoms

PREFERRED RESPONSE: 3- To relieve pain

DISCUSSION

This patient has a metastatic neuroendocrine tumor. Surgical treatment should prioritize palliation of her symptoms. She has high-grade spinal cord compression without neurologic signs or symptoms. Steroids are beneficial for patients with high-grade spinal cord compression caused by tumors, and these drugs should be administered in the acute setting. This patient was appropriately initially treated with conventional radiation. However, she is not a candidate for further radiation because of spinal cord tolerance limits and insufficient clearance between the tumor and spinal cord. Consequently, stereotactic radiation is not an option.

The goal of surgical treatment of this tumor should be palliation of her symptoms rather than cure. A costotransversectomy approach offers the advantage of ventral and dorsal spinal cord access, which is necessary in this case. A sternotomy or transthoracic approach would offer ventral access, but dorsal access would be less than optimal.

Question 76 of 100

An obtunded 80-year-old man was found alone in his apartment after an apparent fall. A CT scan performed in the emergency department shows that he has an extensile injury of an ankylosed cervical spine. The fracture extends across the ossified C5-C6 disk space and into the lamina of C5. There is 1.5 cm of widening between the C5 and C6 vertebrae anteriorly. The patient's family asks you about the long-term impact of the fracture on his functional capacity and survival. You advise them that patients with fractures of the cervical spine with ankylosing conditions have

An unknown prognosis until they can participate in an examination.
Higher rates of neurologic deficit and mortality than other same-age people.
Higher rates of neurologic deficit than other same-age people, but comparable mortality rates.
Similar rates of neurologic deficit and mortality as other same-age people.

PREFERRED RESPONSE: 2- higher rates of neurologic deficit and mortality than other same-age people.

DISCUSSION

Several studies have found that rates of neurologic deficit and mortality are higher for patients with ankylosing spondylitis and a spinal fracture than for age-matched controls. The 2011 work of Schoenfeld and associates, which directly compared patients with cervical fractures in ankylosed spines to age-and sex-matched controls who also had cervical fractures but no ankylosing condition, demonstrated that those with ankylosing spondylitis were at elevated risk for mortality for up to 2 years after sustaining a fracture. In a study by Westerveld and associates, the rate of neurologic deficit among patients with ankylosing spondylitis and a spinal fracture was 57.1% compared to 12.6% among controls.

Question 77 of 100

Which clinical signs are consistent with the diagnosis of cauda equina syndrome?

Saddle anesthesia, hyperreflexia, quadriceps weakness
Decreased motor function in the quadriceps and gastrocnemius, hyperreflexia,? and saddle anesthesia
More than 5 beats of clonus, saddle anesthesia, and bowel incontinence
Urinary retention, saddle anesthesia, and extensor hallucis longus weakness

PREFERRED RESPONSE: 4- Urinary retention, saddle anesthesia, and extensor hallucis longus weakness

DISCUSSION

Cauda equina syndrome is a lower-motor neuron deficit. Hyperreflexia, clonus, and other upper-motor neuron findings would not be seen. Saddle anesthesia, motor weakness, and neurogenic bladder are elements critical to the diagnosis of cauda equina syndrome.

CLINICAL SITUATION FOR QUESTIONS 78 THROUGH 80

Figures 78a and 78b are the axial and sagittal MR images of an otherwise healthy 24-year-old woman who has had 8 weeks of severe leg pain without weakness.

A B

Question 78 of 100

Based on this patient's MR images, at which location would you expect to find altered sensation?

Medial side of left leg
Medial side of left foot
Dorsum of left foot
Lateral aspect of left foot

PREFERRED RESPONSE: 4- Lateral aspect of left foot

Question 79 of 100

A minimally invasive diskectomy technique poses potential for

increased dural tear risk.
a lower success rate for relief of leg pain.
a lower overall complication rate.
a higher rate of recurrent disk herniation.

PREFERRED RESPONSE: 1- increased dural tear risk.

Question 80 of 100

A diskectomy is performed in which the disk space is not aggressively debrided. When compared to techniques that involve aggressive debridement of the disk space, this results in

less intraoperative blood loss.
an increased rate of recurrent disk herniation.
a shorter length of hospital stay.
a higher rate of surgical complications.

PREFERRED RESPONSE: 2- an increased rate of recurrent disk herniation.

DISCUSSION

This patient has disk herniation at the left L5-S1 level. This will generally affect the traversing S1 nerve. The S1 dermatome is on the lateral aspect and sole of the foot.

Surgical treatment generally involves a diskectomy with removal of the herniated fragment. This can be performed via a conventional open approach or minimally invasive endoscopic technique. Several recent meta-analyses have demonstrated equivalent outcomes with regard to leg pain and clinical outcomes. Although minimally invasive techniques have been associated with an increased rate of dural tear, the overall complication rate between the 2 techniques is not significantly different. Several studies have demonstrated a substantial learning curve associated with minimally invasive techniques, and the rate of complications decreases significantly with surgeon experience.

When performing a diskectomy, the herniated fragment alone can be removed (sequestrectomy) or some of the disk that remains in the disk space can be removed (complete diskectomy). Studies have shown no change in surgical time, blood loss, length of stay, or surgical complications when performing a sequestrectomy (compared to a more complete diskectomy). A sequestrectomy is associated with a higher rate of recurrent disk herniation at the surgical level.

Question 81 of 100

Figure 81 is a lateral thoracic spine radiograph of a 76-year-old man with a history of ankylosing spondylitis who falls and strikes his back. He has moderate thoracic discomfort. An initial examination does not reveal neurologic deficits. He is discharged home that day, but returns 3 days later with profound weakness in his legs. Which imaging study should have been obtained at his initial presentation?

Plain radiographs of the lumbar spine
Anteroposterior radiograph of the pelvis
CT scan of the thoracic spine
MRI of the brain

PREFERRED RESPONSE: 3- CT scan of the thoracic spine

DISCUSSION

Patients with ankylosing spondylitis are at high risk for occult vertebral fractures that are not readily detectable on radiographs. The treating surgeon must have a high suspicion for fractures in these patients and pursue further imaging of the spine with CT and (often) MRI. Even among patients who are neurologically intact, fracture displacement and neurologic deterioration can occur if fractures are not recognized early and appropriately stabilized. Fractures in patients with ankylosing spondylitis are extremely unstable and are associated with high risk for delayed neurological deterioration. Although plain film imaging of the entire spine should be considered, occult fractures can easily be missed. Imaging of the sacroiliac joints can be helpful to establish the diagnosis of ankylosing spondylitis but would not identify an occult fracture of the vertebra in this patient.

Question 82 of 100

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

PREFERRED RESPONSE: 1- Increasing coronal plane deformity

DISCUSSION

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 83 of 100

Figure 83 is the CT scan of a 36-year-old man who fell from a roof. Eight hours later at the emergency department he describes low-back pain with numbness and weakness in his bilateral lower extremity. A neurologic examination reveals 2/5 strength in his quadriceps and iliopsoas bilaterally, 2/5 strength in his right anterior tibialis and gastrocsoleus, and 1/5 strength in his left anterior tibialis and gastrocsoleus. Two hours later, strength in his lower extremities has diminished markedly. What is the best next step?

Intravenous (IV) methylprednisolone with a 30-mg/kg loading dose followed by continuous infusion of 5.4 mg/kg/hour for 24 hours
Immediate awake traction reduction
Emergent open reduction/decompression
Admission to the intensive care unit for fluid resuscitation followed by reduction/decompression when stable

PREFERRED RESPONSE: 3- Emergent open reduction/decompression

DISCUSSION

Any progressive neurologic deficit requires emergent surgical intervention. Lumbar injuries cannot be reliably reduced with traction. Although IV steroids and management of mean arterial blood pressure are appropriate interventions for injuries in the region of the conus medullaris, steroids are only indicated when given within 8 hours of injury and are not appropriate as a sole means of management for progressive neurologic deficit.

Question 84 of 100

A 65-year-old woman undergoes a lumbar laminectomy for spinal stenosis at the L3-L4 level. The surgery and postsurgical course are uncomplicated. Eight weeks after surgery she has severe left anterior thigh, groin, and knee pain with ambulation and standing. Which condition is the most likely cause of her symptoms?

Epidural hematoma
Osteoarthritis of the hip
Miralgia paraesthetica
Facet joint pain

PREFERRED RESPONSE: 2- Osteoarthritis of the hip

DISCUSSION

Disorders of the hip can mimic and/or coexist with lumbar spine disorders. The prevalence of hip pain lasting longer than 1 month in patients ages 65 to 74 years is 19%. There is often overlap between their respective signs and symptoms. In a patient with failed back surgery syndrome, hip pathology may have been present before back surgery and not recognized. Osteoarthritis of

the hip typically causes groin and anterior thigh pain. Meralgia paraesthetica is more likely to manifest immediately after surgery. Trochanteric bursitis usually affects the proximal lateral thigh and often can radiate to the distal thigh. Facet joint pain causes low-back pain that can be referred to the gluteal region. Epidural hematoma 6 weeks after surgery is highly unlikely.

Question 85 of 100

Figures 85a through 85c are the sagittal and axial CT scans and sagittal T2 MR image of a 21-year-old man who was thrown from his motocross bike earlier in the day. He now has significant low-back pain; however, he is neurologically intact and has no trouble voiding urine. A standing plain radiograph obtained the next day is shown in Figure 85d. Treatment should involve

C D

resumption of full activity as soon as tolerated.
a brace.
anterior stabilization and fusion.
posterior stabilization and fusion.

PREFERRED RESPONSE: 2- a brace.

DISCUSSION

Disruption of the posterior ligamentous complex is an important determinant of the stability of a burst fracture. This patient is neurologically intact and his MR images do not reveal posterior ligamentous complex (PLC) disruption. The standing radiograph confirms that overall alignment is acceptably and relatively preserved. Nonsurgical treatment with or without a brace is acceptable in this scenario; however, the patient should not be cleared to resume full activity until fracture healing, which may be as long as 3 months after the date of injury. Anterior or posterior surgery should be reserved for patients with PLC disruption, neurological injury, or, in some cases, multiple trauma.

RESPONSES FOR QUESTIONS 86 THROUGH 89

Proximal junctional kyphosis (PJK)
Adjacent segment degeneration
Intraoperative neurological injury
Postsurgical wound infection

Please select the complication listed above that most commonly is associated with a clinical scenario described below.

Question 86 of 100

A 68-year-old undergoes surgery for adult scoliosis with sagittal imbalance that necessitates a large kyphotic correction.

Proximal junctional kyphosis (PJK)
Adjacent segment degeneration
Intraoperative neurological injury
Postsurgical wound infection

PREFERRED RESPONSE: 1- Proximal junctional kyphosis (PJK)

Question 87 of 100

A 47-year-old man undergoes a 3-column osteotomy as part of scoliosis surgery. During closure, somatosensory-evoked potentials decrease.

Proximal junctional kyphosis (PJK)
Adjacent segment degeneration
Intraoperative neurological injury
Postsurgical wound infection

PREFERRED RESPONSE: 3- Intraoperative neurological injury

Question 88 of 100

A 35-year-old undergoes an L4/L5 posterior fusion for spondylolisthesis. Postsurgical radiographs reveal segmental kyphosis and overall sagittal imbalance.

Proximal junctional kyphosis (PJK)
Adjacent segment degeneration
Intraoperative neurological injury
Postsurgical wound infection

PREFERRED RESPONSE: 2- Adjacent segment degeneration

Question 89 of 100

A 62-year-old woman undergoes a posterior laminectomy and fusion from L3 to S1. Postsurgical images show a pelvic incidence (PI) that is significantly larger than the lumbar lordosis (LL).

Proximal junctional kyphosis (PJK)
Adjacent segment degeneration
Intraoperative neurological injury
Postsurgical wound infection

PREFERRED RESPONSE: 1- Proximal junctional kyphosis (PJK)

DISCUSSION

Sagittal balance is becoming increasingly important. PI should be roughly equal to LL. A PI larger than the LL has been associated with a higher incidence of PJK. PJK also is associated with larger sagittal balance corrections. Additional risk factors include higher presurgical thoracic kyphosis, higher postsurgical lordosis, osteoporosis, fusion below L2, and older (greater than 65 years old) patient age. The loss of somatosensory-evoked potentials during surgery, especially during osteotomy correction, is concerning for neurological injury and should be investigated. If no other cause for a change in signals can be identified, the correction should be lessened to take pressure off of the nerves.

Question 90 of 100

Figures 90a and 90b are MR images of a 34-year-old man who is referred to your office by his primary care physician after failing 4 months of nonsurgical treatment that included epidural steroids for severe right arm pain occurring in a C6 distribution. He also has associated paresthesias in this region. The patient is weak in elbow flexion and wrist extension. What are his likely outcomes if he is treated with a posterior foraminotomy instead of anterior cervical diskectomy and fusion (ACDF)?

Similar incidence of postsurgical neck pain with higher risk for radiculopathy recurrence at the same level
Higher incidence of postsurgical neck pain and radiculopathy recurrence at the same level
Higher incidence of postsurgical neck pain and adjacent-level radiculopathy
Lower incidence of adjacent segment degeneration and postsurgical neck pain

PREFERRED RESPONSE: 2- Higher incidence of postsurgical neck pain and radiculopathy recurrence at the same level

DISCUSSION

This patient has a right-sided C5-C6 disk herniation causing C6 radicular symptoms in the right upper extremity. Studies have shown that both ACDF and posterior foraminotomy confer similar results in terms of pain relief and functional outcome. Patients treated with posterior foraminotomy are at higher risk for neck pain and recurrence of radiculopathy at the same level. Those who receive ACDF are at higher risk for occurrence of radiculopathy at an adjacent level.

Question 91 of 100

Figures 91a through 91c are CT images of a 76-year-old man who was involved in a motor vehicle collision. Which of the following scenarios would pose a contraindication to closed reduction of this injury prior to MR imaging?

American Spinal Injury Association Impairment Scale Grade B neurologic deficit
Nondisplaced frontal bone fracture
Obtunded status and a blood alcohol concentration higher than 0.2%
Presence of facet fractures

PREFERRED RESPONSE: 3- Obtunded status and a blood alcohol concentration higher than 0.2%

DISCUSSION

This patient has bilateral jumped facet joints at C6-7. Although MR imaging is useful for revealing disk herniations, cord injuries, and bony fragments, early closed reduction to restore anatomic alignment may be attempted prior to MR imaging because reduction will decrease pressure on the cord. There have been reports of catastrophic outcomes with closed reduction in patients who are intubated when disk fragments are pushed into the spinal cord. Consequently, closed reduction should be attempted only in awake and cooperative patients for whom neurologic status monitoring is possible. MR imaging is generally performed after reduction is attempted (successful or not).

Question 92 of 100

Figures 92a through 92c are the radiographs of a 34-year-old man with low-back pain and an inability to walk upright. What is the appropriate surgical treatment?

A B C

Smith-Peterson osteotomies at T12-L1, L1-L2 and L2-3.
Vertebral column resection through a posterior approach
Anterior-posterior osteotomy
Pedicle subtraction osteotomy at L3

PREFERRED RESPONSE: 4- Pedicle subtraction osteotomy at L3

DISCUSSION

This patient has a marked fixed sagittal imbalance and a mild coronal imbalance. His fused sacroiliac joints indicate ankylosing spondylitis. Sufficient correction likely can be achieved with a pedicle subtraction osteotomy in the midlumbar spine. Smith-Petersen osteotomies necessitate flexibility of the anterior column, which is not associated with this diagnosis. Also, osteoclasis can result in vascular injuries. Vertebral column resection should not be needed in this case.

Question 93 of 100

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

PREFERRED RESPONSE: 1- Aorta

DISCUSSION

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 94 of 100

What are the most likely examination findings of the patient with the images shown in Figures 94a and 94b?

Diminished sensation over the distal anterior thigh and medial leg with quadriceps and anterior tibialis weakness and a diminished patellar tendon reflex on the left
Diminished sensation over the posterior leg, lateral leg, and plantar foot with weakness of plantar flexion and a diminished Achilles tendon reflex on the right
Diminished sensation over the lateral leg and dorsal foot with anterior tibialis and extensor hallucis longus and anterior tibialis weakness on the left 4- Diminished sensation over the lateral leg and dorsal foot with anterior tibialis and extensor hallucis longus and anterior tibialis weakness on the right

PREFERRED RESPONSE: 4- Diminished sensation over the lateral leg and dorsal foot with anterior tibialis and extensor hallucis longus and anterior tibialis weakness on the right

DISCUSSION

The findings on MR imaging reveal a right-sided L4-L5 disk extrusion with cephalad migration of the disk fragment. The axial image shows marked displacement of the traversing right L5 nerve root. The physical findings noted in Response 4 above are typical of a right L5 sensory and motor radiculopathy that would be associated with this level of disk extrusion. Although an extrusion at this level can affect the exiting L4 nerve root resulting in an L4 radiculopathy as described in Response 1, the findings described in this response are contralateral to the disk herniation and not likely to be present. The other responses describe findings associated with left and right S1 radiculopathy, which more typically are associated with an L5-S1 disk herniation/extrusion

Question 95 of 100

A 69-year-old patient with diabetes has had acute-onset back pain and difficulty with ambulation for several hours. Evaluation reveals a temperature of 38.3°C, a white blood cell (WBC) count of 14000/µL (reference range [rr], 4500-11000/µL), C-reactive protein (CRP) level of 120 mg/L (rr, 0.08-3.1 mg/L), erythrocyte sedimentation rate of 130 mm/h (rr, 0-20 mm/h), normal rectal examination findings, and normal sensation to light touch. Motor function testing of the lower extremities reveals 3/5 ankle dorsiflexion and 4/5 plantar flexion strength bilaterally. An MR image reveals a large epidural abscess from L1-5. What is the most appropriate treatment at this time?

Medical management with intravenous (IV) antibiotics and observation
CT-guided aspiration of the abscess before initiating antibiotics
Surgical decompression and IV antibiotics
Blood cultures and re-evaluation in 24 hours

PREFERRED RESPONSE: 3- Surgical decompression and IV antibiotics

DISCUSSION

Epidural abscess is a serious and potentially disastrous condition. Although medical management is effective in some situations, surgical decompression is considered urgent with the presence of a neurological deficit. Medical management can be considered in the case of a neurologically intact patient, particularly when the microorganism has been identified. If medical management is chosen, careful observation and serial examination for neurologic deterioration is required. Surgical decompression is indicated if a patient's neurologic status worsens or if medical management failure is noted. Additionally, diabetes, a CRP level higher than 115 mg/L, WBC higher than 12500/µL , and bacteremia have proven predictive of medical treatment failure. This patient would be a better candidate for urgent surgical decompression and subsequent IV antibiotics than for medical management.

CLINICAL SITUATION FOR QUESTIONS 96 AND 97

Figures 96a and 96b are the CT scans of a 32-year-old man who was thrown from his motorcycle. He has humeral shaft and femoral shaft fractures. A secondary survey reveals substantial tenderness to his lower thoracic spine. He is awake and alert and his movement is limited by pain secondary to the extremity fractures. He is otherwise neurologically intact.

A B

Question 96 of 100

Which factor is most important when making a decision regarding surgery with this patient?

Degree of kyphosis
Mechanism of injury
The patient's other injuries
The patient's bone quality

PREFERRED RESPONSE: 3- The patient's other injuries

Question 97 of 100

If the patient had an isolated spine injury without neurologic deficit, the most appropriate next step would be

anterior corpectomy with percutaneous pedicle screw stabilization.
percutaneous pedicle screw stabilization.
posterior pedicle screw stabilization with fusion.
MRI.

PREFERRED RESPONSE: 4- MRI.

DISCUSSION

The treatment of thoracolumbar burst fractures has evolved over the years. In the absence of a neurologic deficit or a posterior ligamentous complex injury, nonsurgical treatment is as effective as surgery. The degree of spinal canal compromise is not a risk factor for neurologic symptoms. Similarly, although kyphosis may be a marker of more significant injury, the degree of kyphosis does not correlate with chronic pain. In the setting of a burst fracture, MRI can be used to evaluate the integrity of the posterior ligamentous complex. Polytrauma may be considered a relative indication for surgical intervention in the setting of a stable burst fracture.

Question 98 of 100

Surgical restoration of sagittal balance of an adult spinal deformity will have which effect on outcome?

No effect
Improve leg-related symptoms but not back pain
Improve quality of life and back pain
Improve quality of life and leg-related symptoms

PREFERRED RESPONSE: 3- Improve quality of life and back pain

DISCUSSION

The influence of sagittal balance on outcomes following fusion-based procedures for degenerative conditions of the lumbar spine has only recently been appreciated. Restoration of sagittal spinal balance improves low-back-pain outcomes and quality of life. Sagittal spinal balance has not been shown to relieve neurogenic claudication attributable to spinal stenosis.

CLINICAL SITUATION FOR QUESTIONS 99 AND 100

Figures 99a and 99b are MR images of a 59-year-old man with a history of intravenous (IV) drug abuse who arrives at the emergency department with malaise and fever. Upon admission, the patient's temperature is 38.9°C, his white blood cell count is 17000/µL (reference range [rr], 4500-11000/µL), his erythrocyte sedimentation rate is 98 mm/h (rr, 0-20 mm/h), and his C-reactive protein level is 45 mg/L (rr, 0.08-3.1 mg/L). He is admitted to the medical service to evaluate the source of his fevers. On hospital day 1, the patient reports weakness in his left arm and leg. Blood cultures are positive for methicillin-resistant Staphylococcus aureus.

A B

Question 99 of 100

What is the most likely diagnosis?

Central cord syndrome
Cerebrovascular stroke
Spinal epidural abscess
Guillain-Barre syndrome from IV drug abuse

PREFERRED RESPONSE: 3- Spinal epidural abscess

Question 100 of 100

What is the most appropriate treatment at this time?

IV steroids and antibiotics
IV antibiotics
Anterior decompression and fusion
Posterior laminectomy and instrumented fusion

PREFERRED RESPONSE: 3- Anterior decompression and fusion

DISCUSSION

Prompt diagnosis and treatment of patients with spinal epidural abscess is crucial to maintain and/or improve neurologic function. This clinical scenario stresses the importance of advanced imaging studies. It is also important to recognize the imaging features of spinal epidural abscess. T1-weighted gadolinium-enhanced images show ring enhancement with a central nonenhancing, low-signal area. In such a case, urgent decompression is indicated. Because of the location of the abscess, which is anterior to the spinal cord, an anterior decompression and reconstruction (ie, fusion) is probably the best treatment plan. Steroids are contraindicated in the presence of an epidural abscess. IV antibiotics alone will not adequately treat a patient with a neurological deficit. A posterior laminectomy and fusion will not safely allow access to the abscess.

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CLINICAL SITUATION FOR QUESTIONS 1 THROUGH 3

Question 1 of 100

Question 2 of 100

Question 3 of 100

DISCUSSION

RECOMMENDED READINGS

Question 4 of 100

DISCUSSION

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Question 5 of 100

DISCUSSION

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Question 6 of 100

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Question 7 of 100

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Question 8 of 100

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RECOMMENDED READINGS

RESPONSES FOR QUESTIONS 10 THROUGH 14

Please match the scenario described below with the most likely complication listed above.

Question 10 of 100

Question 11 of 100

Question 12 of 100

Question 13 of 100

Question 14 of 100

DISCUSSION

RECOMMENDED READINGS

Question 15 of 100

DISCUSSION

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Question 16 of 100

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Question 17 of 100

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Question 18 of 100

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Question 19 of 100

DISCUSSION

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Question 20 of 100

DISCUSSION

RECOMMENDED READINGS

CLINICAL SITUATION FOR QUESTIONS 21 AND 22

Question 21 of 100

Question 22 of 100

DISCUSSION

RECOMMENDED READINGS

Question 23 of 100

DISCUSSION

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Question 24 of 100

DISCUSSION

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Question 25 of 100

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CLINICAL SITUATION FOR QUESTIONS 26 THROUGH 29

Question 26 of 100

Question 27 of 100

Question 28 of 100

Question 29 of 100

DISCUSSION

RECOMMENDED READINGS

Question 30 of 100

DISCUSSION

RECOMMENDED READINGS

Question 31 of 100

DISCUSSION