Removal of the cervical collar from alpine rescue protocols? A biomechanical non-inferiority trial in real-life mountain conditions

Guillaume Grenier; Marc-Antoine Despatis; Karina Lebel; Mathieu Hamel; Camille Martin; Patrick Boissy

doi:10.1186/s13049-022-01031-3

Removal of the cervical collar from alpine rescue protocols? A biomechanical non-inferiority trial in real-life mountain conditions

Scand J Trauma Resusc Emerg Med. 2022 Jun 27;30(1):42. doi: 10.1186/s13049-022-01031-3.

Authors

Guillaume Grenier¹, Marc-Antoine Despatis¹, Karina Lebel^{2

3}, Mathieu Hamel³, Camille Martin^{2

3}, Patrick Boissy^{4

5}

Affiliations

¹ Faculty of Medicine and Health Sciences, Department of Surgery, Université de Sherbrooke, Sherbrooke, QC, Canada.
² Faculty of Engineering, Department of Electrical and Computing Engineering, Université de Sherbrooke, Sherbrooke, QC, Canada.
³ Research Center on Aging, CIUSSS Estrie CHUS, Sherbrooke, QC, Canada.
⁴ Faculty of Medicine and Health Sciences, Department of Surgery, Université de Sherbrooke, Sherbrooke, QC, Canada. Patrick.Boissy@usherbrooke.ca.
⁵ Research Center on Aging, CIUSSS Estrie CHUS, Sherbrooke, QC, Canada. Patrick.Boissy@usherbrooke.ca.

Abstract

Background: Alpine skiing rescues are challenging because of the mountainous environment and risks of cervical spine motion (CSM) induced during victims' extrications (EXs) and downhill evacuations (DEs). The benefits of applying a cervical collar (CC) over manual in-line stabilization without CC (MILS) in terms of spinal motion restriction during simulated alpine rescues are undocumented. Our hypothesis was that CSM recorded using MILS alone is non-inferior to CSM recorded with a CC according to a 10 degrees margin.

Methods: A total of 32 alpine extrications and 4 downhill evacuations on different slope conditions were performed using a high fidelity mannequin designed with a motion sensors instrumented cervical spine. The primary outcome was the peak extrication 3D excursion angle (Peak 3D θ_EX,) of the mannequin's head. The secondary objectives were to describe the time to extrication completion (tEX) and to highlight which extrication manipulation is more likely to induce CSM.

Results: The median Peak 3D θ_EX recorded during flat terrain extrications using CC was 10.77° (95% CI 7.31°-16.45°) compared to 13.06° (95% CI 10.20°-30.36°) using MILS, and 16.09° (95% CI 9.07°-37.43°) for CC versus 16.65° (95% CI 13.80°-23.40°) using MILS on a steep slope. Peak 3D θ_EX with CC or using MILS during extrications were equivalent according to a 10 degrees non-inferiority hypothesis testing (p < 0.05). Time to extrication completion (tEX) was significantly reduced using MILS without CC on a flat terrain with a median duration of 237,3 s (95% CI 197.8 s, 272.2 s) compared to 358.7 s (95% CI 324.1 s, 472.4 s). During downhill evacuations, CSM with and without CC across all terrain conditions were negligible (< 5°). When CC is used; its installation manipulation induces the highest CSM. When EXs are done using MILS without CC, the logroll initiation is the manipulation inducing the highest risk of CSM.

Conclusion: For experienced ski patrollers, the biomechanical benefits of spinal motion restriction provided by CC over MILS during alpine skiing rescues appear to be marginal and CC use negatively affects rescue time.

Publication types

Equivalence Trial

MeSH terms

Biomechanical Phenomena
Cervical Vertebrae*
Humans
Skiing*