Influence of 5-Day Dry Immersion on Characteristics of Musculoskeletal System of the Back

The aim of this work was to study the influence of microgravity on the structural characteristics of the back musculoskeletal system. The studies were performed on 8 healthy volunteers before and after 3- and 5-days exposure to Dry Immersion (DI) using magnetic resonance imaging. The results of the studies showed that DI is accompanied by a decrease in the physiological curvature of the lumbar spine by an average of 3.51 ± 0.22° with a simultaneous increase in the intervertebral discs height: the most pronounced changes were registered between the lumbar vertebrae L2–L3, L3–L4 and L5–S1. Under immersion conditions, an increase in the height by an average of 1.89 ± 1.03 cm was also observed. According to the MRI studies, starting from the 3rd day of DI there were symptoms of muscles’ atrophy with a significant decrease in the cross-sectional areas of mm. quadratus lumborum, multifidus, erector spinae. During the first two days of DI, the volunteers experienced moderate back pain of 5.33 ± 2.76 points on a 10-point scale. At the same time, there was a high correlation between the severity of pain and a decrease in the cross-sectional areas of mm. quadratus lumborum and multifidus.