CASE                               13                               

A 15-year-old male is unable to move his bilateral lower extremities after being

involved in an ATV accident where the vehicle rolled over multiple times during a jump. There was positive loss of consciousness at the scene. Upon arrival to your tertiary pediatric trauma center he has a Glasgow Coma Score of 15, a left wrist deformity, and reports that he is unable to move or feel his legs. His blood pressure is 105/68, heart rate is 102, respiratory rate is 26, and SpO2 is 98% on room air. He

is in a hard cervical collar, lying comfortably in no acute distress.

Your next action is:

1. Immediate CT scan of cervical, thoracic, and lumbar spine

2. Exchange of hard cervical collar for a Miami-J collar

3. Neurosurgical consultation

4. Evaluation of lungs with stethoscope

5. Obtain radiographs of left wrist to evaluate for fracture

Discussion

The correct answer is (D). Never forget the ABCDEs of Advanced Trauma Life Support (ATLS) when evaluating pediatric trauma patients. Regardless of the various coinciding injuries, all pediatric trauma patients should first be evaluated for (a) maintenance of their airway, (b) breathing and ventilation, (c) circulation and hemorrhage control, (d) evaluation of disability which includes an assessment of neurological status, and (e) environment and exposure of all body surfaces to look for hypothermia, burns, lacerations, ballistic wounds, etc. All of these items should be part of the primary trauma survey and should be evaluated before further work-up into musculoskeletal injuries. The other options are all reasonable choices once evaluation of his air, breathing, and circulation have been evaluated and stabilized.

You undertake a detailed physical examination, which reveals that his skin is closed, and his sensation is not intact distal to the level of his umbilicus. He had no sensation around his rectum and no voluntary rectal tone. He has 5/5 strength in his bilateral upper extremities. He has 0/5 strength in his iliopsoas, quadriceps, hamstrings, tibialis anterior, gastrocnemius, extensor hallicus longus, and flexor hallicus longus bilaterally. He had a negative Babinski test and no signs of clonus bilaterally. He has palpable pulses in his bilateral lower extremities. When his glans penis is squeezed during a simultaneous digital rectal examination, the muscles surrounding his rectum contract around your finger.

What is the neurophysiological pathway by which the bulbocavernosus reflex works?

1. Genitofemoral nerve → afferent pudendal nerve fibers → sacral plexus → efferent pudendal nerve fibers → perineal muscle

2. Genitofemoral nerve → afferent obturator nerve fibers → sacral plexus → efferent obturator nerve fibers → perineal muscle

3. Dorsal penile nerve → afferent ilioinguinal nerve fibers → sacral plexus → efferent ilioinguinal nerve fibers → perineal muscle

4. Dorsal penile nerve → efferent pudendal nerve fibers → sacral plexus → afferent pudendal nerve fibers → perineal muscle

5. Dorsal penile nerve → afferent pudendal nerve fibers → sacral plexus → efferent pudendal nerve fibers → perineal muscle

Discussion

The correct answer is (E). The bulbocavernosus reflex (BCR) is clinically elicited by squeezing the glans penis and digitally palpating the contraction of the bulbocavernosus (BC) muscle. This test was first used for examination of the neurogenic bladder. It is important to test this reflex in patients with potential spinal cord injuries as it tests whether the patient has a true spinal injury or is simply in spinal shock. Spinal shock is defined as temporary loss of spinal cord function and reflex activity below the level of a spinal cord injury. It is characterized by flaccid areflexic paralysis, bradycardia, hypotension, and as previously mentioned, an absent BCR. If the BCR is intact, then there is a significant chance of their neurological deficit being final. The other pathways listed are not involved in the BCR.

Based on his physical examination, what would the patient’s classification according to the American Spinal Injury Association (ASIA) impairment scale?

1. A

2. B

3. C

4. D

5. E

Discussion

The correct answer is (A). The ASIA classification is still widely used today to classify various types of traumatic spinal cord injuries that can occur. The classification is as follows:

A = Complete. No sensory or motor function is preserved in the sacral segments

S4–5.

B = Sensory incomplete. Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4–5 (light touch or pin prick at S4–5 or deep anal pressure) AND no motor function is preserved more than three levels below the motor level on either side of the body.

C = Motor incomplete. Motor function is preserved below the neurological level,** and more than half of key muscle functions below the neurological level of injury (NLI) have a muscle grade less than 3 (Grades 0–2).

D = Motor incomplete. Motor function is preserved below the neurological level,** and at least half (half or more) of key muscle functions below the NLI have a muscle grade >3.

E = Normal. If sensation and motor function as tested with the ISNCSCI are graded as normal in all segments, and the patient had prior deficits, then the AIS grade is

E. Someone without an initial SCI does not receive an AIS grade.

Plain radiographs were taken of the patient’s spine and displayed in Figure 10–20A and B.

Figure 10–20 A–B

Given the clinical and radiographic findings, what is the next step in management to definitively diagnose the patient?

1. Obtain a CT scan of the thoracic and lumbar spine.

2. Obtain an MRI without contrast of the thoracic and lumbar spine.

3. Obtain bending radiographs to observe for instability of the thoracolumbar spine.

4. Obtain electromyogram and nerve conduction studies of the patient’s bilateral lower extremities.

Discussion

The correct answer is (B). The patient’s clinical picture points toward a spinal cord injury, however the plain radiographs seen above show no evidence of any fractures or displacements. Detailed evaluation of the spinal cord and its surrounding paraspinal ligaments is needed in this case, of which only an MRI can reveal. A standard CT scan provides excellent bony detail but does not give much information about the spinal cord unless a CT myelogram is obtained. Given the patient’s clinical findings, obtaining bending radiographs in a potentially unstable spine is not recommended. EMG and nerve conduction studies are not indicated in this patient.

An MRI is obtained and a sagittal view is displayed in Figure 10–21.

Figure 10–21

Given the findings on MRI, what is the best predictor of long-term neurologic outcome in this condition?

1. Age at the time of injury

2. Sex

3. Mechanism of injury

4. Neurologic status at time of presentation

5. Socioeconomic status

Discussion

The correct answer is (D). This patient has a spinal cord injury without radiographic abnormality (SCIWORA), and it was defined by Pang and Wilberger in 1982 as the presence of myelopathy as a result of trauma with no evidence of fracture or ligamentous instability on plain radiographs or tomography. MRI is the gold standard currently to diagnose this condition, however it has been reported that up to 30% to 35% of children with SCIWORA have no evidence of spinal cord abnormality on MRI. The main predictor of long-term neurologic outcome is the neurologic status at the time of presentation; however, in the subset of patients with only minor edema or hemorrhage on MRI, an MRI has been shown to be a better predictor of long-term outcome than neurologic status at presentation. This patient does not have minor edema on MRI. Children with complete lesions very rarely improve, and those with incomplete but severe spinal cord lesions may improve but not to preinjury levels. None of the other listed items have been shown to affect long-term outcomes in patients with SCIWORA.

Objectives: Did you learn...?

The importance of adhering to the basics of ATLS when evaluating all trauma patients regardless of other reported injuries?

The mechanism of action behind the bulbocavernosus reflex and the important ramifications if it is not present?

How to use imaging and the process of deduction to diagnosis SCIWORA? The best predictor of outcome for patients presenting with SCIWORA?