Along with the glory and experience of space travel, many crewmembers and astronauts are returning to Earth with a bad back.
Researchers at the University of California-San Diego have provided new insights into the elevated back pain and disc disease associated with long spaceflights.
Dr. Douglas Chang, associate professor of orthopedic surgery and chief of physical medicine and rehabilitation service at UC San Diego Health and first author of the study, said his study conflicts with previous studies that discounted the impact space had on the back and more extensive research is necessary before a conclusion could be reached.
“These findings run counter to the current scientific thinking about the effects of microgravity on disc swelling,” Chang said in a statement. “Further studies will be needed to clarify the effects on disc height and determine whether they contribute to the increase in body height during space missions and to the increased risk of herniated discs.”
“However, it’s information like this that could provide helpful information needed to support longer space missions, such as a manned mission to Mars,” he added.
Back and spinal pain is common after prolonged spaceflights with more than half of crewmembers reporting spinal pain and astronauts being four times more likely to experience spinal disc herniation in the months returning from spaceflight.
The aim of the research was to understand factors affecting lumbar spine strength and lower back pain during long spaceflights, as well as the spine response after returning to Earth’s gravity.
The studied focused on six NASA crewmembers who spent four to seven months in microgravity on the International Space Station.
Each astronaut had MRI scans on his/her spines before and immediately after the mission, as well as two months after returning to Earth.
The results of the MRI scans indicated significant atrophy of the paraspinal lean muscle during the subject’s time in space. Paraspinal lean muscles are the small muscles that connect to the vertebrae and direct the motion of individual bones, helping to support and prevent misalignment of the spine and allowing for core movement.
According to the study, the ratio of lean muscle decreased from 86 percent prior to the mission to 72 percent immediately following the flight. However, the ratio of lean muscle did increase to 81 percent in the two months following the flight, which is still a decrease from the pre-flight ratio. The researchers also concluded that there was no consistent change in the height of the spinal intervertebral discs.
There are ways to reduce the impact of space travel on the back including core-strengthening exercises and yoga.
More studies on new exercise countermeasures to prevent in-flight muscle atrophy, improve spinal pain and function and to shorten recovery time are also scheduled to be performed.
“Above all this science, what I find is the most unique aspect about space research is the inspiration, curiosity and excitement generated in nearly everyone I talk to in terms of overcoming personal challenges, questioning our place in the Universe and addressing change here at home,” Chang said.
The study was part of a NASA-funded research project led by Alan Hargens, Ph.D., professor of orthopedic surgery at UC San Diego School of Medicine and senior author of the study and co-author Jeffrey Lotz, Ph.D., at University of California-San Francisco.