Goal of the Study?
In this primary research article 1, the authors aim to figure out the cause of disc herniations by learning from the experiences of astronauts.
Why are they doing this study?
When returning from space flight, astronauts experience a higher incidence of disc herniations when compared to the general population. The authors sought to find a greater understanding as to ‘why’. In the process of doing this research, they explored whether specific behavioural movements could be a risk factor. The European Space Agency asked if there was something that could prevent disc herniations in their returning astronauts.
What was done?
The researchers took a deep dive into the anatomy and physiology of the intervertebral disc to learn more.
What did they find?
An astronaut’s spine swells in space due to hyperhydration and a disturbance of the diurnal variation that discs on Earth, experience. With hyperhydration brings the increased likelihood of increased hydraulic pressure. This situation can set the stage for a higher probability of disc herniations with the expansion of the discs in astronauts. The researchers looked at both cervical disc herniations and lumbar disc herniations. They made the overarching suggestion to limit the act of lumbar flexion in returning astronauts until, at least, the discs normalized their hydration levels.
Why do these findings matter?
Understanding the underlying mechanisms of herniated discs is essential for preventing them in astronauts and those on Earth. The discs are a sponge-like dynamic structure, taking on water when unloaded – whether that is space or even during the act of recumbency like that seen in sleep. The gravitational load will exert outward pressure on the annulus fibrosus.
At Dynamic Disc Designs, we have developed models to help in the education of back pain so patients, and students, can see the forces at play and the respective anatomy that these movements can challenge or help.