Prolonged exposure to microgravity experienced by astronauts in space is known to cause low back pain and a heightened risk of intervertebral disc herniations following spaceflight. Our lab, in collaboration with investigators from UC San Diego, has done many studies investigating how prolonged unloading on the spine may lead to pain and injury.
Animal studies
We have conducted multiple studies assessing the biomechanical effects of spaceflight on the spine using “space mice”. Through NASA’s biospecimen sharing program, we were able to experiment on intervertebral discs from mice that spent time in microgravity at the International Space Station. From these studies, we demonstrated that spaceflight reduces the bone density, bending strength and flexibility, and compressive properties of mouse intervertebral segments following 30 days of spaceflight. These findings gave us insight into the unique injury mechanisms that may lead to a heightened risk of post-spaceflight disc herniations in astronauts.
Post-spaceflight recovery of biomechanical properties of murine intervertebral discs
Cadaver studies
Cadaver studies have allowed us to quantify disc changes specifically related to the disc swelling experienced during spaceflight. In an in vitro study, we allowed cadaver discs to free-swell in saline to varying disc heights and found that swelling-induced increases in disc height correlated with increased intradiscal pressure and decreased flexibility in forward bending. This work aids our understanding of biomechanical changes that may occur to the intervertebral disc in the absence of daily gravitational loading.
Cadaver studies
Cadaver studies have allowed us to quantify disc changes specifically related to the disc swelling experienced during spaceflight. In an in vitro study, we allowed cadaver discs to free-swell in saline to varying disc heights and found that swelling-induced increases in disc height correlated with increased intradiscal pressure and decreased flexibility in
The effect of simulated microgravity on lumbar spine biomechanics: an in vitro study.
Astronaut studies
As part of a multi-institutional effort with UCSF, UC San Diego, and NASA, we are tracking changes in lumbar spine function and health before and after 6-months of spaceflight at the International Space Station. We then reassess the crew within 30 to 90 days following landing to observe if and how the lumbar spine recovers from spaceflight. The results from the astronaut imaging study are beginning to help us understand the mechanism between prolonged spinal unloading in microgravity and consequent low back pain and intervertebral disc herniations. We anticipate that data collected during this study development of countermeasures supporting astronaut spine health on future missions to Mars.
