Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
Motion Study Laboratory, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA.
Med Biol Eng Comput. 2022 Dec;60(12):3435-3445. doi: 10.1007/s11517-022-02672-3. Epub 2022 Oct 4.
A two-part simulation process was developed to investigate the facilitation of vertical patient lifts with functional neuromuscular stimulation (FNS) in individuals with spinal cord injury (SCI). First, external lifting forces representing caregiver assistance were applied to a 3D musculoskeletal model representing the patient and optimized to enforce a specific lifting trajectory during a forward dynamic simulation. The process was repeated with and without the activation of the knee, hip, and trunk extensor muscles of the patient model to represent contractions of the paralyzed muscles generated via FNS. Secondly, the spinal compression experienced by a caregiver at the L5/S1 joint while generating these external lifting forces was estimated using a second musculoskeletal model representing the caregiver. Simulation without muscle activation predicted spinal compression in the caregiver model approximately 1.3 × the National Institute for Occupational Safety and Health (NIOSH) recommended "Action Limit." Comparatively, simulations with two unique patterns of muscle activation both predicted caregiver spinal compressions below NIOSH recommendations. These simulation results support the hypothesis that FNS activation of a patient's otherwise paralyzed muscles would lower the force output required of a caregiver during a dependent transfer, thus lowering the spinal compression and risk of injury experienced by a caregiver.
开发了一个两部分的模拟过程，以研究功能性神经肌肉刺激（FNS）在脊髓损伤（SCI）患者中辅助垂直患者提升的效果。首先，将代表护理人员辅助的外部提升力应用于代表患者的 3D 肌肉骨骼模型，并对其进行优化，以在正向动力学模拟过程中强制实施特定的提升轨迹。然后，重复该过程，同时激活和不激活患者模型的膝盖、臀部和躯干伸肌肌肉，以代表通过 FNS 产生的瘫痪肌肉的收缩。其次，使用代表护理人员的第二个肌肉骨骼模型来估计在产生这些外部提升力时 L5/S1 关节处护理人员的脊柱压缩情况。没有肌肉激活的模拟预测护理人员模型中的脊柱压缩大约是国家职业安全与健康研究所（NIOSH）推荐的“行动极限”的 1.3 倍。相比之下，两种独特的肌肉激活模式的模拟都预测了护理人员的脊柱压缩低于 NIOSH 建议。这些模拟结果支持这样一种假设，即 FNS 激活患者原本瘫痪的肌肉将降低辅助转移过程中护理人员所需的力输出，从而降低护理人员经历的脊柱压缩和受伤风险。
