During spaceflight astronauts experience musculoskeletal losses and moderate to severe lumbar pain. There is also a significant incidence of herniated intervertebral disc (IVD) in astronauts, especially in the first year after return to Earth. The pathogenesis of back pain during and after spaceflight is currently unknown. Our current investigation aims to understand this higher incidence of herniated IVDs and back pain. Studies incorporate pre- and post-flight imaging, functional tests, and pain questionnaires of International Space Station (ISS) crew members to ascertain mechanisms of back pain as well as degeneration and injury to spinal structures. Presently six out of 12 ISS crew members have completed all pre- and post-flight testing. Preliminary results to date document: 1) decreased functional back-muscle extensor test (Biering-Sørensen test time), 2) decreased cervical and lumbar muscle functional cross-sectional areas with partial recovery by R+45 (only 21% in neck), 3) increased spine stiffness in flexion, 4) increased spine straightening, 5) decreased quality of vertebral bodies (anterior wedging and endplate irregularities), 6) variable water content changes and 7) no significant changes to disc height and lumbar length. Our results for morphological, biochemical, metabolic, and fluoroscopic kinematics of the spine may aid development of countermeasures to reduce back pain and decrease the incidence of herniated IVDs post-flight. Countermeasures proposed in-flight should include integrated cardiovascular and musculoskeletal exercises to reproduce normal, daily Earth-like stresses. Our long-term objectives are to: 1) promote crew health and well-being inflight, 2) optimize post-flight rehabilitation and translate our findings for Earth Benefit. Supported by NASA grants NNX10AM18G and NNX13AM89G.
Dr. Hargens is Professor and Director of the Orthopaedic Clinical Physiology Lab at the UCSD. He previously served as Chief of the Space Physiology Branch and Space Station Project Scientist at NASA Ames RC and as Consulting Professor of Human Biology at Stanford Univ. He teaches orthopaedic residents, medical/graduate/undergraduate students at UCSD. His recent research concerns gravity effects on the cardiovascular and musculoskeletal systems of humans and animals. One of his students spent 6 months on the ISS, grew and ate vegetables in space, while another flew on the Shuttle five times and was the first astronaut to climb to the top of Mt Everest. Dr. Hargens also investigates exercise devices to maintain astronaut health and performance in space. This research is translated to help post-surgical treatment and rehabilitation of orthopaedic patients, and to improve performance of athletes.
Date(s) - 05/18/2017
1062 Bainer Classroom