Risk of Intervertebral Disc Damage after Prolonged Space Flight (Intervertebral Disc Damage) - 07.15.14
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Among many space-related health changes, crewmembers frequently report back pain while in orbit and when they return to Earth, which physicians believe is related to changes in the astronauts’ intervertebral discs. The discs create a cushion between vertebrae in a person’s spine, and changes to their shape and size can affect the spinal column and back. Crewmembers participating in the Intervertebral Disc Damage experiment complete a battery of six tests before, and after spaceflight, so doctors can determine how the discs change, and whether this correlates to the pain those crewmembers experience.
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Johnson Space Center, Human Research Program, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
Earth Benefits, Scientific Discovery, Space Exploration
ISS Expedition Duration
September 2012 - Ongoing
Previous ISS Missions
- The proposed measures represent a comprehensive set of tests that evaluate exposure severity, potential injury mechanisms, and pain generator localization. This research will aid understanding of spinal pain and deconditioning during prolonged microgravity and of the higher incidence of disc prolapse or herniation following re-exposure to 1-G with a long-term view to prevent such spinal deconditioning with exercise or other physiologic countermeasures.
- After successful completion of the investigation, the PI team will deliver a comprehensive database of microgravity-induced intervertebral disc and vertebral changes (type and magnitude) and a prioritization of these changes as to their deleterious effects and risks for crew member injury based on clinical findings.
- Importantly, this research will have application to back-pain patients on Earth in general and specifically, to patients exposed to long-term bed rest or lack of mobility (spinal-cord injury patients as well as patients suffering lack of exercise, mobility and obesity). This research also has application to abnormal spinal curvature and pain suffered by children wearing heavy backpacks to and from school.
Pre-flight and Post-flight BDC consists of a battery of 6 tests:
MRI (Morphology/Water Content): Once pre-flight, and post-flight on R+1 and R+30-60 MRI scans will be taken while lying flat on the back on a MRI table to measure the spinal bones, discs and muscles. MRI scans will be taken of the lumbar and cervical spine.
MRS: Once pre-flight and post-flight on R+1 and R+30-60 MR spectroscopy will measure metabolites in spinal disc tissues of the lumbar spine.
MRI (Axial Load): Once pre-flight and once post-flight in the R+3-5 timeframe, the subject will visit the Stand-Up MRI in Clear Lake, Texas for an upright MRI study. Here, the PI team will take MRI scans in four different conditions. First, they will take scans lying flat on the back on a MRI table. Second, they will take scans standing in upright posture without any load on the back. Third, they will take scans standing in the same upright posture but with 10% of body weight loaded on the back. Fourth, they will take off the backpack and then take scans of cervical spine while the subject is in a seated position.
Spinal Kinematics: Once pre-flight and once post-flight in the R+3-5 timeframe, the PI team will measure the lumbar spine stiffness and stability using the KineGraph Vertebral Motion Analyzer (VMA). The KineGraph VMA is a system that measures the motion of the bones in the spine using a standard fluoroscope. A fluoroscope is an FDA-approved imaging machine that has been in widespread use for decades, and is used to collect moving video X-ray images of the motion of the spine. In addition to a fluoroscope, the KineGraph VMA also involves the use of a large patient handling device that will assist the subject through a series of controlled spine bends while the fluoroscope is collecting images. These large patient handling devices are needed to standardize the bending, so that it is possible to compare the subject’s spine motion to that of other people. The study consists of taking a series of video X-rays as the subject does different types of spine bending while assisted by the large patient handling devices. The subject will do forward and backward bending, side-to-side bending, bending while standing up, and bending while lying down. To ensure the subject can comfortably do all of these bends, he or she will be asked to perform each of these bends on his or her own before being assisted by the patient handling devices.
Biering-Sorenson: Once pre-flight and once post-flight in the R+3-7 timeframe the subject will also perform a strength test of the abdominal and back muscles.
Back Pain Questionnaires: Once pre-flight and twice post-flight in the R+1-7 and R+30-60 timeframes, the subject will answer two questionnaires per session.
Astronauts report back pain during long-duration microgravity missions and experience an increased likelihood of back injuries, such as herniated discs, after return to Earth. Magnetic resonance imaging, X-rays, bending exercises, and strength tests before and after spaceflight can help identify the suite of changes that can take place in space. Understanding how microgravity changes the structures of a person’s back could help physicians develop exercises or therapies to prevent injury and pain on long-duration space missions, as well as after astronauts return home.
People with limited mobility, including patients on bed rest or with spinal cord injuries, experience some of the same spinal changes as those seen in microgravity. Understanding the origin of spine degeneration in space will aid physicians on Earth to diagnose and treat spine disorders related to inactivity and, conversely, overloading. The study could also have implications for people with curved-spine disorders such as scoliosis, and for children who carry heavy backpacks to school.
Twelve subjects are requested to perform the preflight and postflight baseline data collection for IVD.
This investigation only requires baseline data collection (BDC) both preflight and postflight. No inflight testing will occur.
Chang D, Sayson JV, Chiang S, Riascos-Castaneda R, Walker K, Lotz JC, Hargens AR. Risk of intervertebral disc damage after prolonged space flight. British Journal of Sports Medicine. 2014 April 1; 48(7): 578-579.
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