Comparison of acceleration subjects to other populations: spinal anomaly distribution

Two Armstrong Laboratory (AL) human volunteer subject panels (sustained and impact acceleration) at Wright Patterson AFB, OH, were compared to each other and to other samples of different populations in terms of spinal anomalies. These sample populations were obtained from the scientific literature: French, Norwegian, Netherlands, and U.S. pilots; U.S. Air Force (AF) and Navy subjects, and from representative "normal" civilian populations, and then compared using the proportion parameters for various spinal anomalies. There were only a few common parameters between the two panels and between each panel compared with the foreign military, human subjects, and "normal" population. However, there were two to six times as many similar spinal anomaly incidence rates between the AL panels and the U.S. pilot sample. It was reassuring that the AL subject panels used in AF acceleration research have more in common with AF pilots than other populations in regards to spinal anomalies, even though the pilot sample may not be representative of the true pilot population. Recommendations are to establish a common reference point in nomenclature and description of spinal anomalies (modeled after the French) and to start collecting spinal radiographs on all U.S. pilots. These radiographs would not be for screening but for establishing a database following the occupational pathology of flying. This data would also facilitate comparisons with research acceleration panels, as well as with foreign air forces. Informed decisions can then be made regarding screening criteria for the future as aircraft and ejection seat performance envelopes continue to expand.