Spine Protection in the Austere Environment

To the Editor:

We appreciate the opportunity to comment on the excellent Wilderness Medical Society practice guidelines for spine immobilization in the austere environment. ¹ We commend the authors for their presentation of the evidence, and we generally agree with their well-considered recommendations. However, we have some concerns, mainly about the proposed algorithm, “Recommendations for spine clearance and immobilization in the austere environment” (Figure 2 of the article).

The authors correctly point out that spinal “immobilization” falsely implies that the spine can be immobilized using current techniques. We believe that the newer terms “spinal protection” and “spinal motion restriction” are more accurate. We agree that a vacuum mattress should be used rather than a backboard for spinal protection.

We are surprised that the authors recommend cervical traction during extrication. They mention the dangers of traction with the use of cervical collars. We also would have liked to see the authors address the issue of comfort in patient packaging. For example, is there evidence that patients should be transported in the supine position for spinal protection? Practical experience suggests that transporting patients in the lateral decubitus position can be more comfortable and poses no additional risk.

The authors emphasize the lack of evidence that spinal immobilization confers benefit, and they highlight the known risks. If one concludes that spinal immobilization has no benefit, no patient should be “immobilized.” There would then be no need for the proposed algorithm. We agree with the authors that many injured patients are immobilized unnecessarily, causing significant harm, but we do not believe that spinal motion restriction is useless. For nonambulatory patients, there is no reasonable alternative to stretcher transport with spinal protection. Ambulatory patients seldom, if ever, require special measures to protect the spine. In practice, they may be subjected to unnecessary stretcher transport with associated risks in many austere settings.

The authors present convincing evidence that “appropriately trained personnel can safely use the NEXUS criteria ² or Canadian C-spine Rule” ³ in the prehospital setting to guide selective immobilization of the cervical spine. If the guidelines had been limited to the cervical spine and had stopped with the 1A recommendation to use the NEXUS criteria or the Canadian C-spine Rule, we would have no objection. Our main objection to the untested algorithm developed and presented by the authors is to the specific additional criteria they propose as requirements for spinal protection. We are concerned that there might be patients who would benefit from spinal protection to whom it would be denied using these criteria. Because the algorithm has not been validated, there is no way of knowing how it would perform in practice, unlike NEXUS and the Canadian C-Spine Rule. The criteria for spinal range of motion seem to apply only to the cervical spine. Traditionally, for conscious patients, the decision to protect the thoracolumbar spine has been based on the physical examination, specifically on the presence of neurologic findings or tenderness to palpation. We are not aware of evidence concerning the benefits or harms of this practice.

We wonder if the authors have evidence to support their proposed algorithm other than “careful and meticulous review of the literature…in combination with the collective expertise of the authors…” We are especially interested in the basis for the 2 new binary decision points, “significant spine pain or tenderness (≥7/10)” and “voluntarily able to flex, extend and rotate spine (cervical or thoracolumbar) 45° in each plane, regardless of pain.” These decision points seem quite subjective and would be difficult to apply in the field. We believe that most field providers would be very reluctant to apply flexion and extension in the field, even if there were evidence that it would be helpful.

The risk of unnecessary immobilization could be decreased by including all or parts of a validated instrument, the Canadian C-spine Rule. The Canadian C-spine Rule includes “sitting position,” “ambulatory at any time,” and “delayed onset of neck pain” as criteria for low-risk patients who need only be “able to actively rotate neck 45° left and right” to avoid radiography. ³ Patients who will not need radiography certainly do not need stretcher transport for spinal protection. We call on the authors to revise the algorithm by using validated criteria rather than untested novel decision points to prevent ambulatory patients from being placed on stretchers.