Aerosp Med Hum Perform. 2021 May 1;92(5):312-318. doi: 10.3357/AMHP.5740.2021.
This study aimed to investigate the biomechanical effects of different interventions on astronauts lumbar intervertebral discs in a microgravity environment during spaceflight and in a gravity environment when the astronaut returns. A finite element model of the L4L5 lumbar segment was developed with eight loading schemes representing different interventions. The loading schemes included no intervention, wearing a penguin suit, sleeping in a fetal position, wearing a penguin suit combined with sleeping in the fetal position, reclining for 4 or 16 h/d, and maintaining upright posture for 4 or 16 h/d. Without intervention, the microgravity environment led to increased central pore pressure, radial displacement, and water content in the lumbar intervertebral disc. Wearing a penguin suit combined with sleeping in the fetal position can reduce disc pore pressure, axial stress, radial displacement, and water content to 0.156 MPa, 11.50 kPa, 0.538 mm, and 1.390%, respectively. When astronauts return to the gravity environment, staying upright for 4 h can reduce the pore pressure, axial stress, radial displacement, and water content of the intervertebral disc to 0.222 MPa, 10.72 kPa, 0.373 mm, and 0.219%, respectively. This study showed that wearing a penguin suit and sleeping in the fetal position both have the potential to protect the lumbar intervertebral disc from the negative effects caused by microgravity. Remaining in the upright posture for 4 h per day may help squeeze out the water in the intervertebral disc safely when astronauts return to the gravity environment.
本研究旨在探讨在太空飞行的微重力环境中和宇航员返回后的重力环境中，不同干预措施对宇航员腰椎间盘的生物力学影响。使用 8 种加载方案代表不同的干预措施，建立了 L4L5 腰椎节段的有限元模型。加载方案包括不干预、穿企鹅服、胎儿位睡眠、穿企鹅服结合胎儿位睡眠、每天 4 或 16 小时仰卧、每天 4 或 16 小时保持直立姿势。不干预时，微重力环境导致腰椎间盘中央孔压、径向位移和含水量增加。穿企鹅服结合胎儿位睡眠可将椎间盘孔压、轴向应力、径向位移和含水量分别降低至 0.156 MPa、11.50 kPa、0.538 mm 和 1.390%。当宇航员返回重力环境时，每天保持 4 小时直立姿势可将椎间盘的孔压、轴向应力、径向位移和含水量降低至 0.222 MPa、10.72 kPa、0.373 mm 和 0.219%。本研究表明，穿企鹅服和胎儿位睡眠都有可能保护腰椎间盘免受微重力的负面影响。宇航员返回重力环境时，每天保持 4 小时直立姿势，可能有助于安全地将椎间盘内的水分挤出。
