Removal of the Cervical Spine Collar from Alpine Extrication and Evacuation Skiing Rescue Spinal Motion Restriction Protocols: A Biomechanical Controlled Study in Real-Life Mountain Conditions with a High-Fidelity Mannequin

Background: Alpine skiing rescues are unique because of the mountainous environment and risks of cervical spine motion (CSM) induced during victims’ extrication (EX) and downhill evacuation (DE). Current pre-hospital guidelines recommend the application of full spinal immobilization using various orthotic devices such as cervical collars (CC) when mobilizing and transfer+ring a victim with a suspected spine injury. The biomechanical benefits of applying CC in terms of spinal motion restriction during simulated alpine rescue are undocumented. Methods: Observational design of CSM measurement on a high-fidelity simulation mannequin with a motion sensors-instrumented cervical spine during simulated alpine skiing EX and DE. A total of 32 EXs and 4 DEs on different slope conditions were performed by six experienced active ski patrollers at a Canadian ski resort. The primary outcome was the 3D excursion vector (PeakΔθ) of the mannequin’s head. The secondary objectives were the time to extrication completion (tEX) depending on CC use and to identify which EX event is more likely to induce CSM. Results: PeakΔθ recorded during flat terrain EX using CC was 11.71° +/- 3.61° compared to 16.00° +/- 7.93° using MILS, and 18.29° +/- 9.78° for CC versus 17.90° +/- 4.16° using MILS on a steep slope. PeakΔθ with CC or using MILS during EXs were equivalent according to a 10 degrees non-inferiority hypothesis testing. Time to extrication completion (tEX) was significantly higher using CC as opposed to MILS for both flat and steep terrain conditions (100.6s vs. 219.2s and 106.2s vs. 268.8s longer respectively, 95% confidence interval). During DEs, CSM with and without CC across all terrain conditions were negligible (<5°). Task analysis during EX showed that when CC is used, its installation 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 motion restriction provided by CC over MILS during alpine skiing rescues were found to be at best marginal and CC use negatively affected rescue time. Systematic use of CC during alpine rescue should be reconsidered.