Spine CASES 5

CASE                               30                               

 

You are asked to evaluate a 48-year-old obese woman who presented to the emergency department 48 hours ago with severe low back pain, fevers, and chills of several days duration. CT and MRI demonstrated discitis involving the L4–5 disc space and adjacent osteomyelitis of the L4 and L5 vertebral bodies. No epidural abscess was appreciated on imaging. Standing radiographs demonstrate relatively normal alignment in the affected area. She denies saddle anesthesia and has had no episodes of bowel or bladder incontinence. Her body mass index is 43 and she is diabetic, but she has no other medical conditions; she was found to be HIV-negative at the time of admission. Physical examination demonstrates reproducible back pain with palpation diffusely throughout the lumbar region, but her sensory and motor functions are normal. No upper motor neuron findings are present. Blood cultures obtained before starting vancomycin are growing methicillin-sensitive S. aureus.

The next best step in management is:

1. Request a CT-guided biopsy

2. Surgical debridement and instrumented fusion

3. Infectious disease consultation for antibiotic management

4. Lumbar corset

 

Discussion

The correct answer is (C). The patient has a spondylodiscitis with no evidence of neurologic deficit, epidural abscess, or gross deformity. Blood cultures may identify the responsible organism for infection in as many as 85% of cases of discitis/osteomyelitis. In the current case, the cultures indicate a methicillin-sensitive organism, thus vancomycin would not be necessary. Infectious disease consultation is important in order to optimize the choice of antibiotic. If there is any suggestion that the cultures are unreliable or were not growing an organism, then a CT-directed biopsy should be obtained. While immobilization in the form of a rigid orthosis might be effective in decreasing pain, a lumbar corset would not. Surgical debridement and instrumented fusion are not indicated at this time unless the patient develops a deformity, fails a course of antibiotic treatment, develops a neurological deficit, or has intractable pain that is unresponsive to other measures.

The patient is eventually discharged from the hospital on parenteral antibiotics. She returns to your office for follow-up 6 weeks after discharge. Her back pain has diminished but has not completely resolved. She remains neurologically intact without any subjective complaints or objective deficits noted on examination. Plain film imaging, obtained in your office, shows no evidence of vertebral body collapse or instability. Laboratory tests, ordered by infectious disease doctor, show that her white blood cell count, ESR, and C-reactive protein are now within normal limits. Treatment at this time should be:

1. Surgical intervention

2. Stop antibiotics

3. Follow-up as needed

4. Continue antibiotics for another 6 weeks

 

Discussion

The correct answer is (D). Her laboratory values are indicative of a favorable response to the current antibiotic regimen. Vertebral osteomyelitis typically requires

a total of 12 weeks of antibiotic treatment. At the 6-week mark, infectious disease doctors often recommend conversion to oral antibiotics (if available). However, antibiotics should not be stopped altogether. The patient will probably avoid surgery with this type of positive response but should continue to be followed until there is radiographic evidence of autofusion of the disc space.

Six weeks later, the patient returns to the emergency department with a marked increase in her back pain. She remains neurologically intact. An MRI shows increasing bone destruction of the L4 and L5 vertebral bodies. Plain films demonstrate 20 degrees of segmental kyphosis in this area, though there is no evidence of epidural abscess. The next most appropriate step in treatment should be:

1. 12 more weeks of antibiotics

2. Debridement and circumferential fusion

3. CT-guided biopsy and blood cultures

4. L4 and L5 laminectomy

 

Discussion

The correct answer is (B). The patient has evidence of spinal instability which is an indication for surgical intervention. In light of the evidence of increasing bone destruction and kyphosis, the most appropriate approach is to thoroughly debride the infected vertebral bone and then reconstruct the spine using an interbody strut followed by posterior instrumentation and fusion. Another 12 weeks of antibiotics is not likely to eradicate the infection or treat the underlying instability. A CT-guided biopsy and blood cultures would be indicated if surgery was not planned. A laminectomy would be contraindicated as it will result in greater instability.

 

Objectives: Did you learn...?

 

Indications for the initial management and diagnostic evaluation of patients with vertebral osteomyelitis in the absence of epidural abscess?

 

The appropriate duration of intravenous antibiotic therapy and indications for surgical intervention?

 

The approach to surgical management in the setting of failed response to an appropriate course of antibiotic therapy?

 

CASE                               31                               

Islam Elboghdady; Dr. Anton Jorgensen; Dr. Kern Signh

A 44-year-old construction worker presents to the office with reports of neck pain and sharp arm pain that radiates to the left middle finger. Symptoms began 2 weeks prior. Physical examination demonstrates 5/5 motor strength in both upper extremities except for 4/5 strength in the left triceps. There also is noted a positive Spurling’s sign to the left, reproducing the patients arm pain that radiates into his long finger. The patient obtains an MRI, shown in Figure 1–36 and Figure 1–37.

 

 

 

Figure 1–37 Axial MRI demonstrating a left paracentral herniated nucleus pulposus at C6–7. (Courtesy of Dr. Kern Singh)

 

What is the most likely etiology to explain this patient’s symptoms?

1. Burst fracture of the C6 vertebrae causing spinal stenosis and nerve root impingement

2. C6–7 herniated nucleus pulposus with neuroforaminal compromise

3. Ossification of the posterior longitudinal ligament

4. Cervical spinal stenosis causing myelopathy and spinal cord compression

 

Discussion

The correct answer is (B). This patient most likely has a foraminal herniated intervertebral disc at the C6–7 level causing compression of the exiting C7 nerve root. Disc degeneration is associated with the loss of proteoglycans, water, and cellularity. The outer and inner layers of the annulus fibrosus become incompetent. This structural alteration lessens the threshold of pressure required for the nucleus

pulposus to herniate through the annulus fibrosus. Labor intense activities or high impact sports may result in transiently high increases in disc pressure, increasing the likelihood for a potential disc herniation. Cervical radiculopathy is a clinical diagnosis made based on history and physical examination. The MRI images are included in Figure 1–37 and Figure 1–38.

 

 

 

Figure 1–38 Sagittal MRI demonstrating a posterior intervertebral disc fragment at the C6–7 level. (Courtesy of Dr. Kern Singh)

 

What is the best next step in management for this patient?

1. Anterior cervical discectomy and fusion

2. Posterior cervical foraminotomy and discectomy

3. Transforaminal epidural steroid injections

4. Pharmacologic management (NSAIDs)

 

Discussion

The correct answer is (D). The majority of disc herniations will resolve spontaneously. The herniated nucleus pulpous (HNP) will be resorbed, as demonstrated on long-term radiographic assessment of patients who underwent nonoperative treatment. The first step involves pharmacologic treatment with nonsteroidal anti-inflammatory drugs (NSAIDs). Similarly, corticosteroids may also be utilized to minimize the symptoms being experienced by the patient. It should be noted that corticosteroids have not been demonstrated to provide long-term pain

relief. There are no randomized controlled trials to support the routine utilization of muscle relaxants for the initial management of HNP. Opiates may be utilized for initial pain control but the dosing should be short-term, as long-term narcotic utilization is not indicated.

Physical therapy should also be encouraged in addition to pharmacologic management. Although PT has not been demonstrated to improve outcomes associated with cervical HNP, it may provide symptomatic relief.

If pharmacologic management and physical therapy are ineffective, epidural steroid injections (ESI) may be attempted. Some evidence suggests that corticosteroid ESIs carry greater efficacy than anesthetic or saline injections and may limit surgical intervention. Similarly, selective nerve root blocks (SNRB) can be utilized for diagnostic purposes or therapeutic relief. Improvement following SNRB localizes the source of pain to the irritated nerve root. Unlike ESIs, SNRBs function by local steroid deposition near the nerve root as it exits the foramen without infiltration into the spinal canal.

Following 3 months of nonoperative management, the patient reports worsening left arm weakness. Physical examination demonstrates numbness over the left third digit and 3/5 muscle strength with elbow extension in the left arm. The patient has exhausted NSAIDs, physical therapy, and epidural steroid injections.

What is the next best step in management?

1. Selective nerve root block

2. Anterior cervical discectomy and fusion

3. Continued nonoperative management

4. Laminectomy

 

Discussion

The correct answer is (B). The majority of disc herniations resolve spontaneously with time, and therefore, nonoperative management should be encouraged even after 3 months. However, this patient demonstrates worsening motor strength. As such, this patient will likely benefit from an anterior cervical discectomy and fusion (ACDF) to limit the progression of symptoms. ACDF will serve to maintain the segmental cervical lordosis and restore disk height to decompress the C7 nerve root. The limitations of ACDF include diminished motion at the fused spinal segment and potential risk of adjacent segment degeneration and instability. One alternative to ACDF includes cervical disc arthroplasty (CDA), which is proven to be noninferior to ACDF for the management of degenerative disk disease. An

additional option is a posterior cervical foraminotomy and discectomy. A foraminotomy is not indicated for central disc herniations but can be an effective, motion-sparing procedure for patients with foraminal compromise secondary to osteophytes and/or disc herniation.

Which of the following complications are specific to anterior cervical spine surgery?

1. Dysphagia

2. Dysphonia

3. Cervical soft tissue swelling

4. Recurrent laryngeal nerve injury

5. Horner’s syndrome

6. Infection

7. Excessive blood loss

8. Incidental durotomy

   1. 1, 2, 3, 4, 5

   2. 1, 3, 5, 7, 8

   3. 3, 5, 6, 8, 8

   4. 5, 6, 7, 8

   5. 2, 4, 5, 7, 8

 

Discussion

The correct answer is (A). Dysphagia is a unique complication that is specific to anterior cervical spine surgery. Retraction of the recurrent laryngeal nerve and the esophagus can contribute to impaired swallowing. Dysphagia typically improves and resolves within days following the anterior cervical procedure. Dysphonia is the result of injury or compression of the recurrent laryngeal nerve, which is essential for vocal cord function. Prevertebral soft tissue swelling typically peaks on the second and third days postoperatively and dissipates by 6 weeks. Horner’s syndrome is a very rare complication of ACDF that results from injury to the cervical sympathetic trunk (CST). The CST lies superficial to the longus coli, excessive retraction may result in injury presenting as a triad of ptosis, miosis, and anhydrosis. Infection and blood loss are complications inherent to any surgical procedure. Vertebral artery injury and incidental durotomies are more likely with a posterior cervical spine procedure than an anterior cervical approach.

Objectives: Did you learn...?

 

 

Initial management of a cervical HNP; importance of nonoperative management? Next steps after failure of nonoperative management?

 

The complications specific to an ACDF?

 

CASE                               32                               

Dr. Alejandro Marquez-Lara; Dr. Eric Sundberg; Dr. Kern Singh

A 62-year-old, overweight (BMI = 28.9 kg/m2) female with no significant medical or surgical history presents complaining of progressive lower back pain for the past 3 months. Her symptoms worsen with prolonged walking/standing and improve with sitting. The neurovascular examination is unremarkable and no motor deficit is appreciated. Imaging studies are obtained (Figs. 1–39 to 1–42).

 

 

 

Figure 1–39 Axial T2-weighted MRI demonstrating central spinal stenosis at the L4–5 disc level. (Courtesy of Dr. Kern Singh)

 

 

 

Figure 1–40 Sagittal T2-weighted MRI demonstrating L4–5 spondylolisthesis with canal narrowing. (Courtesy of Dr. Kern Singh)

 

 

 

 

Figure 1–41 Sagittal T1-weighted MRI demonstrating right foraminal narrowing. (Courtesy of Dr. Kern Singh)

 

 

 

Figure 1–42 Sagittal T1-weighted MRI demonstrating left foraminal narrowing.

 

What is the next step in management?

1. Counsel the patient to lose weight and return in 3 months

2. Nonsteroidal anti-inflammatory medication, physical therapy, and weight loss

3. Epidural steroid injection

4. Lumbar total disc replacement

 

Discussion

The correct answer is (B). This patient demonstrates symptoms of back pain associated with an L4–5 spondylolisthesis and spinal stenosis. Most patients (76%) with degenerative spondylolisthesis and spinal stenosis without radicular symptoms respond well to nonoperative management. Directionally specific physical therapy, namely flexion-based Williams’ exercises, may have some benefit in patients with positional specific symptomatology.

After 6 months, the patient has minimal relief of symptoms. She continues to complain of back pain aggravated by standing and walking and improving with flexion and sitting. In addition, she mentions intermittent lower extremity pain, numbness, and tingling that radiates to the dorsum of her foot. Her walking and standing tolerance have also diminished.

What is the next step in management?

1. Microscopic lumbar discectomy

2. Continue nonoperative management for another 6 months

3. Epidural steroid injection (ESI)

4. None of the above

 

Discussion

The correct answer is (D). The patient continues to have back pain and now complains of neurogenic claudication. In this case, recent evidence from the Spine Patient Outcomes Research Trial (SPORT) suggests that nonoperative management in a symptomatic patient with spondylolisthesis and spinal stenosis will benefit greater from surgical intervention than nonoperative management (ESIs).

On physical examination, sensation to light touch over the dorsal foot and lateral aspect of the leg is diminished and you notice weakness with great toe extension on the right side compared to the left.

What surgical option is best for this patient at this time?

1. Limited decompression (e.g., laminoforaminotomy)

2. Laminectomy

3. Decompression and fusion without instrumentation

4. Decompression and fusion with instrumentation

 

Discussion

The correct answer is (D). Patients with lumbar spinal stenosis from spondylolisthesis who have failed conservative management for 3 to 6 months are associated with better outcomes with surgical decompression and fusion than continued nonoperative management. The surgical technique should aim to decompress the neural structures and stabilize the affected segment. Instrumented fixation is associated with higher fusion rates than noninstrumented techniques. Flexion–extension radiographs may be obtained to help determine the severity of instability. In those patients with nonmobile spondylolisthesis and collapsed disc spaces, it is reasonable to offer the patient a laminectomy with preservation of the midline structures. In these cases, the risk of progression of the spondylolisthesis may be low, and a surgical fusion may be obviated.

What are the potential benefits of an interbody fusion?

1. Better restoration of disc and foraminal height

2. Higher fusion rates than posterolateral fusions

3. Better short- and long-term clinical outcomes

4. Both A and B

5. A, B, and C

    

   Discussion

   The correct answer is (D). Interbody fusion procedures including anterior, transforaminal, and posterior interbody fusions improve disc and foraminal height. In addition, some studies have reported higher fusion rates with interbody implants due to the higher surface area for bone graft incorporation. Currently, there is no evidence that demonstrates better outcomes with interbody techniques compared to traditional posterolateral fusions in patients with degenerative spondylolisthesis. There is an increased risk of injury to neural elements from the retraction required for disc excision and placement of the interbody device. The additional costs, potentially greater operative times, and blood loss should also be taken into consideration.

    

   Objectives: Did you learn...?

    

   Nonoperative treatment with directionally specific physical therapy is an acceptable, initial treatment option in the setting of spondylolisthesis with spinal stenosis?

    

   Decompression and instrumented fusion is the most accepted surgical technique to treat spondylolisthesis with spinal stenosis after exhausting nonoperative management?

    

   The addition of an interbody fusion device can help restore the disc height and promote a stable fusion. However, further research is warranted to characterize the short- and long-term outcomes with this technique as compared with the more traditional posterolateral fusion?

    

   CASE                               33                               

    

   A 55-year-old patient with a history of smoking and congestive heart failure sustained a traumatic spondylolisthesis at L4–5 following a motor vehicle accident. Due to the degree of instability, an anterior and posterior spinal fusion was

   performed from L3–5. The procedural time was prolonged due to extensive instability. At the 3-week follow-up, the patient reports severe back pain, fever, and drainage from the surgical wound-site. The ESR was 100 mm/h with a white blood cell count of 15,000/mm3. Plain film radiographs demonstrated a stable construct and no evidence of segmental deformity.

   Which of the following are published risk factors for the patient’s current state?

   . History of smoking

   . Congestive heart failure

   . Male gender

   . Multilevel fusion

   . Longer duration of surgery

   1. 1 and 2

   2. 1, 2, 3

   3. 1, 4, 5

   4. 1, 3, 4, 5

   5. 1, 2, 3, 5

   6. 1, 2, 3, 4, 5

 

Discussion

The correct answer is (C). The elevated ESR and WBC at 3 weeks with concomitant fever and wound drainage are suspicious signs for postoperative wound infection. The ESR typically peaks at 1 week following surgical intervention. Postoperative infections can be attributed to multiple patient- and surgical-related risk factors. In this scenario, the surgical risk factors include a multilevel fusion secondary to greater tissue dissection, operative time, and instrumentation. In addition, this patient carries a history of smoking, which is a published risk factor for postoperative complications including infection, pseudarthrosis, and poor wound healing. Conversely, male gender and a history of congestive heart failure are not published risk factors for postoperative spinal infection.

Which of the following imaging modalities should be obtained?

1. Contrasted CT

2. Noncontrasted MRI

3. Contrasted MRI

4. Bone scintigraphy

5. Ultrasound

 

Discussion

The correct answer is (C). MRI with gadolinium enhancement is the best radiographic modality to detect surgical site infections (SSIs). If spinal instrumentation is present, MRI should be utilized with metal artifact reduction sequences. Vertebral and soft tissue changes on imaging must be differentiated between two different states: normal postoperative changes and vertebral osteomyelitis. Both states are associated with type 1 end plate changes that are characterized by adjacent marrow edema and hypointense signal on T1 imaging. Vertebral osteomyelitis may also be associated with high signal intensity in the disc space. In addition, gadolinium contrast serves to demonstrate areas of enhancement in the disc space. Vertebral osteomyelitis is associated with circumferential disc enhancement whereas linear areas of enhancement are more resemblant of normal postoperative changes.

CT can be utilized to assess for implant failure and bony remodeling/destruction. Bone scintigraphy will not differentiate between the normal postoperative state versus infection, as both states are associated with increased metabolism and uptake. Gadolinium contrast is essential to visualize the pattern of disc enhancement.

Imaging studies indicated a subfascial infection at L4–5 with bony destruction and fluid collection. Which of the following should be the next course of action?

1. IV antibiotics

2. Bedside incision and drainage

3. Surgical debridement and irrigation with retention of instrumentation

4. Surgical debridement and irrigation with removal of instrumentation

5. CT-guided aspiration and drainage

 

Discussion

The correct answer is (C). The type of postoperative spinal infection dictates the next appropriate course of action. Superficial SSIs often respond to a course of IV antibiotics and/or surgical drainage. Conversely, medical therapy alone is likely

unsuccessful with subfascial infections due to poor tissue vascularity and penetration of antibiotics. Deep SSIs typically warrant extensive debridement of infected and necrotic tissue with removal of extraneous bone or graft pieces. The surgeon should aim to retain instrumentation in an effort to maintain the stability of the spinal column. If implants are loose, they can be removed and replaced; however, the patient must be monitored closely for potential pseudarthrosis or spinal instability. In this patient’s case, the infection developed at 3 weeks and is considered an early postoperative infection. In cases of a late deep SSI (6 months to 1 year), the surgeon may elect to remove instrumentation to adequately clear the infection, as bony arthrodesis is likely forthcoming if not already achieved. The surgeon must be cognizant that in cases of deep infection, serial surgical debridements are likely necessary to effectively clear the infection. In addition, there is some evidence promoting the utilization of antibiotic impregnated beads or grafts following surgical debridement in order to address the issue of poor IV antibiotic penetrance to the infection site.

What is the best course for antibiotic therapy in this patient?

1. No antibiotic therapy is warranted following surgical debridement

2. Course of oral antibiotic therapy

3. Course of intravenous antibiotic therapy

4. Course of IV antibiotic therapy followed by course of oral antibiotics

5. Lifetime oral antibiotics

 

Discussion

The correct answer is (D). Initially patients with postoperative spinal infections should be placed on broad spectrum antibiotics following surgical debridement until a culture and sensitivity profile of the organism(s) is obtained. The most common pathogen is S. aureus. Typically, a 6-week course of intravenous antibiotic therapy is recommended followed by a course of oral antibiotics. Infectious disease specialists should be consulted to determine the type, dosage, and duration of antibiosis appropriate for each patient. For patients with methicillin-resistant S. aureus infections, new guidelines recommend 6 weeks of intravenous antibiotic therapy followed by oral antibiotics until fusion is achieved. Some physicians advocate removal of the hardware once the arthrodesis has been obtained in order to eradicate any potential for infectious recurrence.

 

Objectives: Did you learn...?

 

The risk factors for postoperative spinal infection include smoking, multilevel fusion procedures, and prolonged duration of surgery among other factors?

 

Contrasted MRI is paramount for the diagnosis of a postoperative spinal infection?

 

The management of a postoperative spinal infection is dependent upon the extent of infection?

 

Antibiotics carry an integral role for the management of postoperative spine infections. Infectious disease specialists should be consulted to aid in selection and length of therapy?

 

CASE                               34                               

 

A 20-year-old man presents to the trauma bay after striking his head while diving into a shallow pool. He was not able to get out of the pool himself and was extricated by others. Upon presentation, he is alert and oriented. Physical examination of his upper extremities demonstrates 5/5 strength in shoulder abduction and elbow flexion, 4/5 in the wrist extension, and 1/5 strength of elbow extension, wrist flexion, and finger abduction/flexion. Lower extremity strength is 1/5 in all groups. Sensation is intact along the lateral shoulder, arm, and forearm, but decreased along the middle finger and medial forearm and arm. Lower extremity sensation is globally decreased. Figure 1–43A–C are axial and sagittal CT images of his cervical spine. Figure 1–43D is a sagittal MRI of his cervical spine.

 

 

Figure 1–43 A–D

 

The patient’s cervical spine injury is best described as which of the following?

1. Hangman’s fracture

2. Lateral mass fracture

3. Flexion teardrop fracture

4. Facet dislocation

 

Discussion

The correct answer is (C). The imaging studies demonstrate a flexion teardrop injury. The important injury characteristics include a triangular fracture fragment along the anteroinferior aspect of the vertebral body that is thought to be produced by shear forces via a flexion–compression moment. The paramedian CT images demonstrate gapping in the facet joints which indicates that the facet capsule has been disrupted. Flexion teardrop injuries should be distinguished from anterior avulsion fractures, often called extension teardrop fractures, which also can involve the anteroinferior corner of the vertebral body. However, the fracture is produced by failure in tension and is more commonly seen in elderly patients who sustain an extension injury mechanism. A Hangman’s fracture refers to an injury specifically of the pars interarticularis of C2. A Chance fracture, also known as a flexion–distraction or seat belt injury, occurs in the thoracolumbar region and exhibits

evidence of both posterior and anterior structure failing under tension. Though the facet joints do appear to be gapped on the CT images, they are not dislocated, thus the injury should not be described as a facet dislocation.

This injury most likely occurs via which of the following mechanisms?

1. Hyperextension

2. Flexion–compression

3. Flexion–distraction

4. Forced rotational

 

Discussion

The correct answer is (B). This injury pattern is most commonly produced by a compressive force imparted on a flexed spine. Compression–flexion injuries, as described by Allen and Ferguson, can present in varying stages ranging from simple blunting of the anterior vertebral body (best described as a compression fracture) to unstable injures with teardrop fragments and a characteristic sagittal split, pronounced kyphosis, and facet gapping as exhibited in the above injury. Hyperextension injuries may show widening anterior with associated fracture of the posterior elements but would not be likely to present with kyphotic deformity. Flexion–distraction injuries in the cervical spine, the prototype of which is bilateral facet dislocations, show substantial widening posteriorly with subluxation, dislocation, or fracture dislocation of one or both facet joints. Rotational injuries most commonly present with unilateral pedicle or articular process fractures with varying degrees of translational deformity.

Based on the patient’s examination findings, his motor level would best be described as:

1. C5

2. C6

3. C7

4. T1

 

Discussion

The correct answer is (B). Utilizing international standards, the motor level is defined as the lowest (most caudal) level with key muscle strength of at least grade 3/5, provided that muscle function cranial to this segment is full (5/5). This patient’s elbow flexion is 5/5 and wrist extension is 4/5, both of which represent C6 function.

Elbow extension and wrist flexion are 1/5, which represent C7 function. Finger flexion and abduction represent C8 and T1 function, both of which are 1/5 in this patient. Thus, this patient’s most caudal segment with at least 3/5 strength is C6.

Provided that the patient is medically stable, definitive treatment should be:

1. Immobilization in a hard cervical collar

2. 6 weeks of cervical traction followed by halo-vest application

3. Laminectomy of C3 through C7

4. C5 corpectomy and instrumented fusion

 

Discussion

The correct answer is (D). In general, nonoperative treatment of a patient with a neurological deficit is not ideal. With the surgical goals being decompression of the spinal canal, realignment, and stabilization, anterior corpectomy and instrumented fusion addresses all three. Closed treatment with a hard cervical collar would not adequately stabilize the spine or be able to maintain alignment. While halo-vest immobilization has been described for the treatment of this injury type with comparable neurological outcomes as anterior corpectomy and fusion, radiographic outcomes are inferior, that is, kyphosis persists. Notwithstanding, 6 weeks of cervical traction would not be advisable in a patient who is fit to safely undergo surgery. A laminectomy would cause further destabilization of the spine in this case and would likely not results in substantial decompression of the spinal cord.

 

Objectives: Did you learn...?

 

The imaging findings suggestive of a cervical flexion teardrop fracture, including the nuances that distinguish it from other more stable injuries?

 

The typical injury mechanism associated with teardrop injuries and spectrum of injury patterns produced by this mechanism?

 

How to determine the motor level of a spinal cord injury based on evaluation of key muscle function?

 

Appropriate treatment considerations for this injury pattern?

 

CASE                               35                               

 

A 43-year-old man was struck by a car while walking along the road. Neurologic examination demonstrates 5/5 strength in all muscle groups in his upper extremities but 0/5 strength throughout the lower extremities. Though sensation throughout the lower extremities is absent, he has diminished yet present perianal sensation to light touch and pinprick. His imaging studies are shown in Figure 1–44A–C.

 

 

 

Figure 1–44 A–C

 

The patient’s neurologic injury can be best described by which of the following American Spinal Injury Association (ASIA) impairment scale grades?

1. ASIA A

2. ASIA B

3. ASIA C

4. ASIA D

 

Discussion

The correct answer is (B). The ASIA impairment scale helps to characterize the

severity of a spinal cord injury. It relies on determining the degree of motor and sensory function below the level of injury. ASIA A refers to a patient with no motor or sensory function below the injury level. ASIA B denotes that some sensory function is preserved below the level of injury. ASIA C denotes that there is some motor function below the injury level, but that it is less than 3/5. ASIA D indicates that motor function below the injury level is at least 3/5. ASIA E is normal motor and sensory function below the level of injury. In the above case, there is some, albeit diminished, sensation in the perianal region. This indicates an ASIA B grade. While this is certainly not useful function at this time, it is an important prognosticator of neurological recovery as the patient demonstrates some function of the spinal cord below the level injury.

In the trauma bay, the patient’s blood pressure suddenly drops to 80/50 mm Hg while his pulse increases to 120 bpm. A 1-L fluid bolus of lactated Ringers is infused which normalizes his blood pressure and pulse. This clinical phenomenon is best characterized as which of the following?

1. Hypovolemic shock

2. Spinal shock

3. Neurogenic shock

4. Autonomic dysreflexia

 

Discussion

The correct answer is (A). The patient’s hypotension was combined with tachycardia that responded well to judicious fluid administration. This suggests that he was experiencing hypovolemic shock. Neurogenic shock, often following a spinal cord injury, typically manifests with hypotension combined with bradycardia. Neurogenic shock is more frequently associated with cervical level spinal cord injury, and fluid resuscitation should be administered carefully as to avoid volume overload. After achieving euvolemia, vasopressors should be used to support blood pressure in lieu of delivering more fluid. Neurogenic shock occurs as a result of the lack of sympathetic tone in the peripheral vasculature. Spinal shock refers to a transient syndrome of flaccid areflexic paralysis and anesthesia after spinal cord injury which hinders accurate determination of ASIA grade and prognosis. It does not affect blood pressure or heart rate. The resolution of spinal shock is heralded by the return of the bulbocavernosus reflex. Importantly, conus level injury can result in persistent loss of the bulbocavernosus reflex in the absence of spinal shock. Autonomic dysreflexia is a syndrome involving massive imbalance of sympathetic

discharge in response to pain below the level of neurologic injury. It often manifests as severe headache, flushing, and extreme elevation of blood pressure with compensatory bradycardia and can be life-threatening. The most common triggering source is severe bladder distension.

During early management and resuscitation of this patient, which of the following is currently recommended in order to maximize neurological recovery?

1. Systemic hypothermia using an intravenous cooling system

2. High-dose methylprednisolone infusion

3. Maintaining mean arterial pressure of 85 mm Hg

4. Injection of olfactory ensheathing cells into the injury site

 

Discussion

The correct answer is (C). Although there are no level I studies on this issue, current consensus among spinal surgeons is that supporting spinal cord perfusion using vasopressors, if necessary, to maintain a mean arterial blood pressure of 85 mm Hg is ideal. In addition, supplemental oxygen should be used as necessary to ensure that adequately oxygenated blood is perfusing the injured spinal cord. The use of methylprednisolone had become widespread after the second and third National Acute Spinal Cord Injury Studies reported a positive effect. Subsequent analyses of these data, however, have suggested that no conclusive benefit was demonstrated. Additional concerns over risks of infection, bleeding, and pulmonary complications as well as an effect on fusion have resulted in high-dose steroids being considered a treatment option rather than a recommendation at this time. In fact, many major trauma centers in the United States and Canada no longer routinely use high-dose steroids for spinal cord injured patients. Systemic hypothermia is currently an experimental therapy under study in the acute setting. Injection of olfactory ensheathing cells is also an experimental intervention that might be used in a delayed setting but not immediately following a spinal cord injury.

Definitive management of this patient’s spinal injury should be:

1. Anterior corpectomy, strut graft, and instrumentation

2. Custom-molded thoracolumbar orthosis

3. Laminectomy and short-segment fusion

4. Long-segment instrumented fusion

Discussion

The correct answer is (D). The imaging studies demonstrate a thoracic fracture-dislocation. Using the Thoracolumbar Injury Classification Scale this would be considered a translational injury which is assigned three points for injury morphology. The patient’s incomplete spinal cord injury would be assigned three points in the neurologic status category. The injured posterior ligamentous complex would also be assigned three points. Injuries with overall scores greater than four are generally managed surgically. Translational or rotational injuries are typically treated from a posterior approach if the vertebral translation has led to abnormal canal alignment, as seen in this case. Multiple points of transpedicular fixation can be useful for reduction maneuvers and to provide sufficient stability to maintain alignment and promote fusion. Importantly, realignment in such cases usually effects decompression of the spinal canal. Anterior corpectomy, strut graft, and anterior instrumentation constructs may be utilized in the setting of comminuted burst fractures with neurologic injury from retropulsed bone. In the translational injury presented, realignment is more challenging from an anterior approach in the lateral decubitus position, and an isolated short anterior construct is not ideal with the degree of circumferential ligamentous disruption. While the benefit of a laminectomy in such a case can be debated, a short-segment fusion (i.e., instrumented only the level above and below) does not offer sufficient strength to reduce and stabilize the injury. Nonoperative treatment in a custom-molded brace would not be advised.

 

Objectives: Did you learn...?

 

Essential distinguishing features of complete versus incomplete spinal cord injuries?

 

Definitions and characteristics of hemodynamic shock, neurogenic shock, and spinal shock, which are commonly confused entities?

 

Current recommendations for early supportive management of spinal cord-injured patients?

 

A strategy for evaluating the essential features of thoracolumbar injuries to determine relative stability and the benefit of surgery?

 

CASE                               36                               

 

A 57-year-old woman with a 20-year history of rheumatoid arthritis presents with progressively severe neck pain, clunking, and suboccipital headaches. Pain slightly improves with use of a soft collar. No loss of fine motor dexterity, balance, or bowel/bladder function is noted. Her flexion–extension lateral radiographs are shown in Figure 1–45A and B.

 

 

 

Figure 1–45 A–B

 

The patient’s imaging studies demonstrate which of the following conditions?

1. Atlantoaxial instability

2. Subaxial subluxation

3. Basilar invagination

4. Diffuse idiopathic skeletal hyperostosis

 

Discussion

The correct answer is (A). Atlantoaxial instability is the most common pattern of affliction in the rheumatoid spine. Rheumatoid synovitis at the C1–2 joints and around the stabilizing transverse, apical, and alar ligaments leads to atlantoaxial instability. In the figures provided, there is a substantial gap in the atlantodens interval noted with the neck in flexion as compared to extension, in which the subluxation reduces. Subaxial subluxation results from rheumatoid induced laxity and inflammatory involvement of the subaxial facet and uncovertebral joints. This commonly manifests as a step ladder–type sagittal deformity, often at C3–4 and C4–

5. Considering that the films provided do not demonstrate this area of the spine, one cannot make this diagnosis. Basilar invagination occurs from rheumatoid-induced bony and cartilaginous destruction of the occipitoatlantal and atlantoaxial joints, occipital condyles, and C1 lateral masses. Vertical translation of the odontoid can result in brainstem compression or excessive kyphosis of the cervicomedullary junction. Significant neurologic compromise or sudden death can occur. Based on the lateral views of the spine, the tip of the odontoid process does not appear to

protrude into the foramen magnum. Diffuse idiopathic skeletal hyperosto (DISH) is an ossifying diathesis of the spine that is unrelated to rheumatoid arthritis. It manifests as large flowing osteophytes bridging three or more relatively well-preserved disc spaces of the cervical spine. This patient’s radiographs do not demonstrate evidence of DISH.

Which of the following measurements most strongly indicates that surgical management is warranted in a patient with C1–2 instability from rheumatoid arthritis? (AADI, anterior atlantodens interval; PADI, posterior atlantodens interval)

1. AADI of 4 mm

2. AADI of 6 mm

3. PADI of 18 mm

4. PADI of 12 mm

 

Discussion

The correct answer is (D). The anterior atlantodens interval (AADI) is measured on a lateral view from the anterior odontoid to the posterior surface of the anterior ring of C1. Normal AADI in adults is less than 3 mm. The posterior atlantodental interval (PADI) is measured from the posterior odontoid to the anterior surface of the posterior ring of C1. The normal PADI is greater than 14 mm. The PADI has been found to be a better predictor for the development of paralysis than the AADI. Patients with PADI less than 14 mm have increased risk of neurologic deficit and should therefore be recommended for surgery, even if asymptomatic. Patients undergoing surgery who have a PADI less than 10 mm are less likely to experience postoperative recovery of neurologic deficit.

Figure 1–45C shows a sagittal MRI of the cervical spine of the patient. The white line that is drawn measures 12 mm. This line demonstrates which of the following parameters?

1. Posterior atlanto dens interval

2. Space available for the cord

3. MacGregor’s line

4. Powers ratio

 

 

 

Figure 1–45 C

 

Discussion

The correct answer is (B). The line is demonstrating the actual space available for the cord (SAC) which can only be accurately measured by MRI since some patients may have significant pannus extending posterior to the odontoid (aka dens) that will not be visible by radiographs. A true SAC less than 13 mm is generally considered an indication for surgery. The posterior atlantodental interval (PADI) is measured on a lateral plain x-ray. MacGregor’s line is drawn from the hard palate to the base of the occiput. Basilar invagination (BI) is defined as migration of the superior odontoid more than 4.5 mm above this line. Power’s ratio is used to evaluate for possible traumatic occipitocervical dissociation.

Which of the following is the best surgical option for the described patient?

1. Transoral dens resection and C1–2 fusion

2. Occipitocervical fusion

3. C1–2 fusion with screw stabilization

4. C1–2 Gallie fusion

 

Discussion

The correct answer is (C). The patient has a reducible C1–2 subluxation without neurologic deficit. Transoral removal of the odontoid and pannus is not required and has significant morbidity. Regardless, pannus resorption is frequently seen after

stabilization and fusion. As there is no evidence of basilar invagination, extension to the occiput is not required. Posterior C1–2 fusion with sublaminar wires, such as the Gallie technique, is an option, but usually requires postoperative halo immobilization and has fallen out of favor recently. More rigid forms of internal fixation, such as transarticular C1–2 screws or C1 lateral mass screws with C2 pedicle screws, provide more rigid fixation and higher fusion rates when combined with bone grafting.

 

Objectives: Did you learn...?

 

The different patterns of cervical spine involvement in patients with rheumatoid arthritis?

 

The difference between the AADI and PADI and associated treatment recommendations?

 

 

The concept of the SAC, the impact of periodontoid pannus, and the role of MRI? The surgical treatment considerations for patients with AAI?

 

CASE                               37                               

 

You are called to the trauma bay to evaluate a 47-year-old male who was a restrained driver in a high speed motor vehicle accident. Vital signs: BP 120/80, HR 100, SaO2 95%. On your initial evaluation, his Glascow coma scale score is 15 and he is cooperative with the examination. He has ecchymosis in his chest. He

complains of chest, back, and abdominal pain. He has normal sensation with 5/5 motor strength but the iliopsoas is 3/5 on the left side. AP and lateral radiographs are shown Figure 1–46A–B.

 

 

 

Figure 1–46 A–B

 

What is your next course of action?

1. Place patient in a TLSO brace.

2. Mobilize the patient with physical therapy.

3. Start trauma dose steroids.

4. Send patient for spiral CT of the thoracolumbar spine.

 

Discussion

The correct answer is (D). The patient was involved in a high-speed accident with significant force. A compression fracture is noted at L1. Better visualization is needed to determine the stability of this injury. CT is becoming the study of choice in these cases because the high sensitivity and specificity of CT in detecting thoracolumbar injuries.

CT of the thoracolumbar spine shows a burst fracture at L1 with 20% height loss and 30% canal compromise (Fig. 1–47). There is also widening of the interspinous space between T12 and L1. He has not lost any additional motor strength.

 

 

 

Figure 1–47

 

What is your next course of action?

1. Order MRI lumbar spine.

2. Place patient in a TLSO brace.

3. Start trauma dose steroids.

4. Strengthen his left leg with physical therapy.

 

Discussion

The correct answer is (A). In this case, better visualization is necessary because the patient has a neurologic injury. Even though his neurologic injury has not progressed, better visualization with MRI is recommended to determine how much compression exists and also to evaluate for any other potential lesions such as a disc herniation.

An MRI is obtained and there is a 50% canal compromise seen (Fig. 1–48). No other injuries are noted.

 

 

 

Figure 1–48

 

What is your next course of action?

1. Place patient is a TLSO brace.

2. Start trauma dose steroids.

3. Strengthen his left leg with physical therapy.

4. Discuss surgery with the patient.

 

Discussion

The correct answer is (D). In the setting of neurologic compromise with canal compression, surgery is the most appropriate answer.

 

Objectives: Did you learn...?

 

The correct order of ordering CT versus MRI in flexion/distraction injuries?

 

When it is appropriate to consider closed versus open treatment in flexion/distraction injuries?

 

CASE                               38                               

 

In your clinic, you see your first patient of the day. He is an otherwise healthy 34-year-old male. He complains of pain that begins in his mid-back and clearly radiates

across his back into his abdomen. Examination shows normal sensation and 5/5 motor strength. His knee and ankle jerk reflex is 2+.

What is your next course of action?

1. Place patient in a lumbar corset.

2. Initiate physical therapy for lumbar strengthening.

3. Obtain MRI of the lumbar spine.

4. Obtain MRI of the thoracic spine.

 

Discussion

The correct answer is (D). In this case, there is suspicion of a compressive lesion on the spinal cord or nerve root in the thoracic spine. Advanced imaging is suggested here versus a corset or physical therapy because a diagnosis is warranted prior to initiating any treatments. MRI of the thoracic spine is more appropriate than MRI of the lumbar spine because the radiation of the pain to the abdomen is more suggestive of a thoracic lesion versus a lumbar lesion.

MRI reveals an acute thoracic disc herniation, your next course of action is:

1. Place patient in a lumbar corset.

2. Send the patient for thoracic epidural or nerve root injection.

3. Admit the patient for emergent discectomy.

4. Recommend a discectomy via a transthoracic approach.

 

Discussion

The correct answer is (B). At this time, his symptoms are relatively stable. Most acute thoracic disc herniations may be treated nonoperatively. Relative surgical indications include myelopathy, lower extremity weakness or paralysis, bowel or bladder symptoms, or chronic radiculopathy that is refractory to conservative measures. Treatment may include a course of nonsteroidal anti-inflammatories, rest, modification of activities, and physical therapy. In this case, the patient is having radicular pain and injections are an option.

He has had his epidural injections and his pain was improved for a few weeks. But he twisted his back over the weekend and now has complains of progressive numbness and subjective weakness in his legs. He also complains of worsening pain that radiates across his back and to his abdomen. Examination shows patchy areas of decreased sensation and 4/5 motor strength in both lower extremities. The knee and ankle jerk reflex is 3+ whereas biceps is 2+. Babinski is mildly positive and he

demonstrates three beats of clonus.

 

What is your next course of action?

1. Initiate physical therapy for lower extremity strengthening.

2. Place patient in a lumbar corset.

3. Discuss surgical decompression.

4. Send for another epidural injection.

 

Discussion

The correct answer is (C). In most instances, thoracic disc herniations may be treated nonoperatively. Surgical indications in this case include progressive myelopathy and lower extremity weakness.

 

Objectives: Did you learn...?

 

Appropriate imaging in detecting disc herniations?

 

When nonoperative versus operative treatment is most appropriate in thoracic disc herniations?