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. 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 θEX,) 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. The median Peak 3D θEX 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 θEX 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. 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.

中文翻译：

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从高山救援方案中移除颈托？现实山区条件下的生物力学非劣效性试验

由于山区环境以及在受害者解救 (EX) 和下坡疏散 (DE) 期间诱发的颈椎运动 (CSM) 风险，高山滑雪救援具有挑战性。在模拟高山救援过程中，在脊柱运动限制方面，应用颈托 (CC) 相对于不使用 CC (MILS) 的手动在线稳定系统的好处尚未得到证实。我们的假设是，单独使用 MILS 记录的 CSM 不劣于根据 10 度余量使用 CC 记录的 CSM。使用设计有颈椎运动传感器的高保真人体模型，在不同的坡度条件下进行了总共 32 次高山救援和 4 次下坡撤离。主要结果是人体模型头部的峰值解脱 3D 偏移角 (Peak 3D θEX,)。次要目标是描述解救完成时间 (tEX) 并强调哪种解救操作更有可能诱发 CSM。使用 CC 在平坦地形解救过程中记录的峰值 3D θEX 中位数为 10.77°（95% CI 7.31°–16.45°），相比之下，使用 MILS 为 13.06°（95% CI 10.20°–30.36°）和 16.09°（95% CI 9.07） °–37.43°) 与 16.65° (95% CI 13.80°–23.40°) 在陡坡上使用 MILS。根据 10 度非劣效性假设检验，在解救过程中使用 CC 或使用 MILS 的峰值 3D θEX 是等效的 (p < 0.05)。在中位持续时间为 237.3 秒（95% CI 197.8 秒，272.2 秒）与 358.7 秒（95% CI 324.1 秒，472.4 秒）相比，使用无 CC 的 MILS 显着缩短了解救完成时间 (tEX) ）。在下坡疏散时，在所有地形条件下具有和不具有 CC 的 CSM 可以忽略不计（< 5°）。使用 CC 时；它的安装操作会产生最高的 CSM。当 EX 使用没有 CC 的 MILS 完成时，logroll 启动是导致 CSM 风险最高的操作。对于经验丰富的滑雪巡逻员来说，在高山滑雪救援过程中，CC 相对于 MILS 提供的脊柱运动限制的生物力学益处似乎是微不足道的，并且 CC 的使用会对救援时间产生负面影响。