A new Spine study analyzed changes in astronauts' lumbar paraspinal muscle cross-sectional area and intervertebral disc height when on an International Space Station mission for six months. Alan R. Hargens, PhD, of UC San Diego School of Medicine in Sacramento, and Jeffrey C. Lotz, PhD, of UCSF, led the NASA-funded research.
The study included six NASA astronauts who were imaged supine with a 3T MRI. The imaging occurred pre-flight, post-flight, 33 days post-landing and 67 days post-landing. The study measured functional cross-sectional area measurements of the paraspinal muscles at the L3-4 level. Additionally, researchers measured intervertebral disc heights at the anterior, middle and posterior lumbar levels.
Here are five highlights:
1. The researchers found the astronauts' paraspinal lean muscle mass decreased from 86 percent of the total paraspinal muscle cross-sectional area to 72 percent, right after the mission.
2. Sixty-eight percent of post-flight loss recovery occurred over the next six weeks.
3. The study also revealed the astronauts' lumbar intervertebral disc heights did not significantly differ at any point.
4. The researchers found presence of "lumbar spine [paraspinal muscle] atrophy after long-duration spaceflight." They noted some functional cross-sectional area recovery with "46 days post-flight in a terrestrial environment, but it remained incomplete compared to pre-flight levels."
5. The researchers hope their findings will further support spine health and prevent spinal injuries during space missions.