Assessing the Spine

   Management of spinal cord injuries is a fundamental EMS skill, challenging providers and bringing risks to patients. Ensuring that we do not immobilize needlessly--or fail to immobilize when indicated--requires a thorough assessment.

Scenario

   You are called to the scene of a rollover MVC. Your patient apparently self-extricated from the vehicle prior to your arrival and is ambulatory at the scene. He is calm and alert, responds to all questions appropriately and cooperates fully with your physical exam. Assessment findings and vital signs are:

• Point tenderness and deformity to the left forearm and superficial lacerations to both hands;
• Denies loss of consciousness;
• No signs of mental impairment or intoxication;
• Denies posterior midline cervical spine tenderness;
• Exhibits intact sensory and motor function in all extremities;
• Pulse: 112 bpm;
• Respirations: 20 bpm;
• BP: 136/74.

Functional Anatomy

   The spine is composed of five discrete regions: cervical, thoracic, lumbar, sacrum and coccyx. Of these, the cervical and lumbar regions--the two least supported by other elements of the skeleton--are the most commonly fractured.

   Branching from the spinal cord between each vertebrae are 31 pairs of spinal nerves composed of sensory, motor and autonomic fibers. Each of these nerve pairs is responsible for a discrete body region known as a dermatome. The efferent, or motor, fibers carry impulses from the central nervous system to muscles or organs, while afferent sensory fibers carry impulses from the muscles or organs to the CNS for interpretation. Motor or sensory deficits in the dermatomes innervated by these nerves are strong clues to damage to these nerves and/or their corresponding vertebrae.

Assessment

   The National Emergency X-radiography Utilization Study (NEXUS), designed to limit the number of unnecessary cervical spine x-rays, defined a set of clinical criteria to identify those patients at low risk of spinal injury.¹ The NEXUS exam criteria are as follows:

• No evidence of intoxication--The mere smell of alcohol metabolites on a patient's breath does not always indicate intoxication, but caution is warranted.
• Normal level of alertness--Patients must exhibit present mental capacity to participate in the exam, and follow instructions without hesitation.
• No midline posterior cervical spine tenderness--Walk your fingers down the cervical spine from the base of the skull to between the shoulder blades, assessing for point tenderness.
• No focal neurological deficits--Weakness is the most common neurological deficit, and may be bilateral or confined to one extremity. Numbness is relatively rare and is most commonly described as tingling, burning or a "funny feeling." Have the patient squeeze your hands and flex both feet. Touch all four extremities and check for sensory deficits. The Canadian C-spine Rule (CCR) adds several criteria that place patients at higher risk of a spinal cord injury:²
• Age over 65;
• Significant mechanism of injury;
• Significant injury above the clavicles.

   Studies indicate that NEXUS and CCR are more than 99% accurate at ruling out cervical spine injury, and thus the need for an x-ray. In the field, those same criteria can be used effectively to determine the need for spinal motion restriction.

Spinal Injury Patterns

   Brown-Séquard syndrome results from an incomplete hemisection of the spinal cord, most often from penetrating trauma. The syndrome is characterized by loss of motor function and proprioception (ability to sense position, location, orientation and movement) on the side of the lesion, and contralateral loss of temperature and pain sensation.

   Central cord syndrome most often results from hyperextension of the cervical spine, and presents with greater weakness in the upper limbs than in the lower limbs. Some CCS patients still have enough motor function in the lower extremities to enable them to walk. Bladder dysfunction may be present, most commonly presenting as an inability to urinate.

   Anterior cord syndrome may result from bony fragments impinging on the cord or pressure on spinal arteries. Symptoms include variable deficits in motor function, pain sensitivity and sensitivity to light touch. Proprioception and sensitivity to deep pressure is often intact.

   Cauda equina lesion may result from lumbosacral fractures, or iatrogenically from lumbar punctures or spinal anesthesia. The syndrome is characterized by saddle anesthesia and bowel and bladder dysfunction. Since the spinal cord proper ends at the level of the second lumbar vertebrae, some regeneration of damaged nerves may be possible.

   Spinal cord injury without radiographic abnormality (SCIWORA) is an uncommon phenomenon in which focal neurological deficits are present, but no evidence can be found on x-rays. The syndrome occurs most often in children below the age of 8.

   Priapism in the patient with spinal cord injury is caused by interruption in sympathetic fibers below the level of the lesion, resulting in unopposed parasympathetic stimulation. It is important to note, however, that there are other common causes of priapism, such as sickle cell disease and adverse reactions to erectile dysfunction medications.

   Neurogenic shock is caused by interruption of sympathetic nervous system innervations to the vasculature below the lesion, resulting in massive vasodilation and hypotension. While tachycardia is usually not present in the neurogenic shock patient, the presence of an elevated heart rate does not rule out the condition.

Summary

   The decision to apply spinal motion restriction should be based upon assessment findings. Mechanism of injury is a consideration, but ultimately the decision should be made on objective physical exam findings. The patient in the scenario has a significant mechanism of injury and a potentially distracting forearm fracture. However, was the pain from the fracture enough to distract him from participating in the exam and giving reliable answers? Did he need to be collared and boarded? When in doubt, or when local protocols are ambiguous, err on the side of caution.

Clinical Pearls

• Spinal motion restriction is not a benign procedure. Increased pain and anxiety are common, and vomiting and aspiration, respiratory decompensation, increased intracranial pressure and decubitus ulcers are very real risks. Do not immobilize needlessly. Have a reason.
• Children exhibiting SCIWORA syndrome should be have spinal motion restriction precautions due to suspected instability of spinal ligaments in the affected area.
• Neurogenic shock does not occur with injuries below the T6 vertebrae. Hypotension in patients with injuries below that level is almost always due to hemorrhage.

REFERENCES

   1. Hoffman JR, Mower WR, Wolfson AB, Todd KH, Zucker MI. National Emergency X-Radiography Utilization Study Group. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. NEJM 343(2): 94-99, Jul 13, 2000.

   2. Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian c-spine rule for radiography in alert and stable trauma patients. JAMA 286(15): 1,841-48, Oct 17, 2001.

   Steven "Kelly" Grayson, NREMT-P, CCEMT-P, is a critical care paramedic for Acadian Ambulance in Louisiana. He has spent the past 14 years as a field paramedic, critical care transport paramedic, field supervisor and educator. He is a frequent EMS conference speaker and the author of the book En Route: A Paramedic's Stories of Life, Death, and Everything In Between, and the popular blog A Day in the Life of An Ambulance Driver.

   William E. "Gene" Gandy, JD, LP, has been a paramedic and EMS educator for more than 30 years. He has implemented a two-year associate's degree paramedic program for a community college, served as both a volunteer and paid paramedic, and practiced in both rural and urban settings and in the offshore oil industry. He lives in Tucson, AZ.