Abstract
To the Editor:
I applaud both the intent and the work that went into producing the new Wilderness Medical Society (WMS) spine immobilization guidelines. 1 And, I agree with the expert panel that “In the austere environment, the goal of spinal assessment and care should not be to definitively rule out or recognize all forms of spine injury. Rather, the goal should be to minimize the risk of missing or exacerbating a potentially unstable spine injury. The risk of missing such an injury should be appropriately calibrated against the risk of exposing rescuers to the potential for serious injury or causing further injury to the patient beyond that which occurred during the index traumatic event.”
That said, I disagree with the algorithm proposed in the guidelines for the following reasons: 1) The WMS algorithm, as explained and diagrammed, is confusing and does not incorporate the existing National Emergency X-Radiography Utilization Study (NEXUS) 2 criteria and Canadian C-spine Rule (CCR) 3 ; the two combine to make it excessively difficult to remember and teach. 2) The authors’ attempt to lower the immobilization threshold using spine pain and tenderness as a benchmark is highly subjective, and although it may appear intuitively reasonable, is not based on any current data. 3) The spinal range of motion testing used in the WMS algorithm originated with the CCR under the premise that the patient has not been subjected to a significant mechanism of injury (MOI). In the WMS algorithm, there is a significant MOI. 4) Finally, in contrast to the expert panel’s stated goal (quoted above), the WMS algorithm does not assess or balance any potential risk to the patient or rescuers as a direct result of immobilizing the patient’s spine.
I would like to offer a different algorithm based on a risk-benefit analysis for discussion and consideration in its place, subject to the definitions and notes described below. I believe the algorithm outlined in the Figure represents what an experienced guide and medical professional would do when presented with an awake and otherwise ambulatory patient who fails the NEXUS or CCR criteria and where spinal immobilization and subsequent evacuation would be unduly hazardous to the patient or rescuers.
Definitions
1) The MOI for spinal immobilization includes blunt trauma with a mechanism suspicious for spinal trauma or an unknown MOI; isolated penetrating trauma is not considered such a mechanism and does not require immobilization. 2) Reliable means no significant thoracic or other distracting injury, normal mental status (Glasgow Coma Scale 15), and normal pain response. 3) Neurological deficit means abnormal motor/sensor examinations or numbness, tingling, or shooting pain in extremities not explained by a coexisting extremity injury. 4) Answers to all 3 questions in the risk-benefit assessment must be “yes” to consider self-evacuation. 5) The “spine as a long bone” strategy considers the head, thoracic/upper lumbar spine (above L-3), and femurs as “long bones,” and the cervical spine and lower lumbar spine (L-4, L-5)/pelvis as “joints.” If pain or tenderness or both can be isolated to the cervical spine using the NEXUS criteria, the patient’s femurs may be safely flexed, although lateral movement should be avoided. If pain or tenderness can be isolated to the pelvis using the NEXUS criteria, the patient’s neck does not need to be immobilized.
Discussion
The blue boxes in the algorithm (Figure) identify decision points; the information may have been gathered earlier. For example, the MOI for spine injury is typically assessed during the scene survey; the patient’s mental status and neurological function are typically assessed during the primary and secondary surveys. If a patient requires full spinal immobilization, the potential for pressure sores can be reduced by using a vacuum splint or thick padding (eg, several air or foam mattresses and sleeping bags). If a head-injured patient requires full spinal immobilization, consider using a soft or heavily padded cervical collar to reduce the potential for the ongoing development of increased intracranial pressure. Using the “spine as a long bone” strategy may permit selective immobilization of the patient’s spine and prevent some iatrogenic injuries during prolonged transport. At the patient’s request, a padded cervical collar (eg, padded SAM splint) or thoracic/lumbar support (eg, internal frame backpack with hip belt) can be used if it increases patient comfort during a self-evacuation. There is no research that establishes a timeline for the development of injuries caused by “prolonged” spine immobilization on a well-padded litter or backboard. Pressure sores can begin to develop in a few hours with some patients on a hard surface (eg, unpadded backboard).
Spinal immobilization guidelines for remote and austere environments. CCR, Canadian C-spine Rule; MOI, mechanism of injury; NEXUS, National Emergency X-Radiography Utilization Study; PRN, as needed.
The risk-benefit assessment described in the algorithm is both subjective and objective, and the final result will depend on the training and skills of the rescuers. The proposed algorithm significantly lowers the immobilization threshold in an austere environment with an otherwise ambulatory patient who has no neurological deficit but who has failed either the NEXUS or CCR examination, and when self-evacuation would significantly lower the overall risk for the patient or rescuers during the evacuation. Unlike the WMS algorithm, this algorithm maintains the reliability of the CCR guidelines and NEXUS criteria while significantly reducing the immobilization threshold when the risk warrants it. For those already familiar with the CCR and NEXUS guidelines, the algorithm is easy to remember and teach.