that astronauts are at an increased risk of intervertebral disc damage during loading scenarios experienced during exploration missions (re-entry to a gravitational field and activities on planetary surfaces).
To date, flight data related to potential back injuries have focused on spine elongation and the well-established effects of mechanical unloading on intervertebral discs.
Exploration missions on planetary surfaces may also introduce habitability issues that could induce excessive torsional stress, an established risk factor for herniation of anulus fibrosus.
Assumptions and presumptions considered include: During the 84-day Skylab 4 mission, the spine elongation of one astronaut was measured and recorded to the 1/16th inch (Thornton, 1987).
A retrospective chart review to evaluate the incidence of intervertebral disc damage after several astronauts developed cervical or lumbar herniated nucleus pulposus in the immediate postflight period.
[11] This study specifically compared the incidence of intervertebral disc damage in astronauts to an age-matched control population of persons who have never flown in space.
This review also ought to clarify whether there is an increased risk for intervertebral disc damage due to: It is unclear if changes due to spaceflight increase the risk of intervertebral disc damage since there is evidence that many of the injured astronauts have previously had multiple exposures to excessive G-forces as high-performance jet pilots (6-20 G's) or to vibrational forces as helicopter pilots.