EMS World

SEP 2018

EMS World Magazine is the most authoritative source in the world for clinical and educational material designed to improve the delivery of prehospital emergency medical care.

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Page 45 of 51

EMSWORLD.com | SEPTEMBER 2018 45 ditions, including cervical spondylosis and ankylosing spondylitis, also increase the risk for SCI after trauma. Spinal Cord Anatomy The spinal cord is a conduit that con- veys motor commands from the brain to the muscles and sensations from the peripheral sensory receptors to the brain. It begins at the end of the brain stem, passes through the foramen magnum, and continues down through the spine to the lumbar vertebrae. The spinal cord ends around the level of the L1 vertebra and turns into the cauda equina, a bundle of spinal nerves that carries information from the spinal cord to the pelvic organs and lower limbs. Spinal nerves exit from each level of the spinal cord and split up into different nerves to send signals to muscles and receive information from sensory receptors. The spinal nerves are named after their corresponding verte- brae, so the spinal nerve that exits at the C5 vertebra is called the C5 spinal nerve. There are some important nerves that travel within the spinal cord and can impair respirations or cause hemodynamic insta- bility if damaged. The nerve that controls the diaphragm exits the spinal cord at the level of C3–C5. Therefore, injuries above C5 can impair breathing (the rhyme "C3 through C5 keeps the diaphragm alive" is a helpful memory tool). In addition, neu- rons for the sympathetic nervous system also travel through the spinal cord. These neurons leave the spinal cord at the T1–L2 levels and eventually travel to innervate the heart, blood vessels, bronchi, and other organs. Therefore, injury to the spinal cord can interrupt the sympathetic ner- vous system, resulting in a form of shock. The level of injur y within the spinal cord can be estimated from the pattern of muscle weakness and sensory defi- cits observed in the patient. Landmarks for identifying the level of SCI include the clavicles, which are at the C4 level; nipple line, which is at the T4 level; and umbilicus, which is at the T10 level. 9 For example, if the patient has lost sensation below the nipple line, you know the spinal cord is injured at the T4 level. If the patient has no sensation at the clavicles, you should suspect an injury at or above the C4 level and maintain a high degree of suspicion for diaphragmatic weakness and respira- tory failure. There can be overlap between levels, so the injury level and its pattern of sensory deficits may vary slightly. Spinal Cord Syndromes Sensory and motor neurons travel down different parts of the spinal cord. There- fore, injuries to only certain areas of the spinal cord can cause unique patterns of motor and sensory deficits. These differ- ent patterns of deficits are called spinal cord syndromes. They include: • Complete transection—When the entire spinal cord is affected. These patients have complete loss of sensation and paralysis below the level of the injury. • Brown-Séquard (hemicord) syndrome— When half the spinal cord is affected. Patients present with paralysis on one side of the body and loss of sensation on the other. • Anterior cord syndrome—When the anterior por tion of the spinal cord is affected. Patients present with paralysis and loss of pain sensation below the level of injury but have preserved sensation of proprioception and vibration. • Central cord syndrome—When there is damage to the center of the spinal cord. This syndrome typically occurs in older adults with degenerative conditions of the cervical spine. Patients present with weakness of the upper extremities that's worse than the lower extremities. For EMS providers, it is not important to memorize the specific patterns of neu- rological deficits associated with each of these syndromes. Rather, it is more impor- tant to be aware that patients may have one of these syndromes rather than a com- plete transection, resulting in a pattern of neurologic deficits that is different than in a complete transection. For this reason, EMS providers should not discount the possibility of SCI in patients with sensory deficits or weakness on only one side of the body (i.e., Brown-Séquard syndrome) or weakness of the upper extremities but not the lower (i.e., central cord syndrome). Assessment Assessment of the patient with suspected spinal cord injury includes determining the mechanism of injury, performing a physi- cal exam of the spine, and evaluating for neurological deficits. Evaluating the mechanism of injur y is helpful for gauging the likelihood the patient has suffered a spinal injury. Falls from height, particularly when patients land on their heels, cause axial loading of the spine that can lead to SCI. 10 Diving injuries, which cause axial loading on the head, are also at high risk for causing SCI. The deceleration forces in motor vehicle collisions can cause flexion and hyper- extension injuries to the cervical spine. 10 Motor vehicle collisions at high risk for serious injury include head-on and side- impact collisions, ejection from a vehicle, and pedestrians struck by a vehicle. Consider the mechanism of injury in the context of the patient's underlying medical history. For example, a patient with osteo- porosis could experience a spine fracture from a mechanism that would not injure the spine of an otherwise healthy patient. All patients with suspected SCI after trauma should be fully examined with a rapid trauma assessment so as not to miss any injuries. Palpation of the spine is an important component. To palpate the spine, log-roll the patient while main- taining manual c-spine stabilization. Palpate the entire spine to identify point tenderness over spinous processes, gaps between vertebrae, and step-offs. Point tenderness along the spine is concerning for spinal injury, while gaps between ver- tebrae or step-offs should raise suspicion for vertebral dislocation or fracture. The initial neurological exam to screen for SCI involves testing whether motor strength and sensation are intact in the upper and lower extremities. First ask the patient if they're experiencing any numb- ness or tingling, which are both signs of SCI. Next, gently touch the patient's distal upper and lower extremities to test sensa- tion. Motor strength in the upper extremi- ties can be tested by asking the patient to grasp your fingers, while strength in the lower extremities can be tested by ask-

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