+Gz Exposure and Spinal Injury-Induced Flight Duty Limitations

BACKGROUND: The present study aimed to find out if possible differences in early military flight career +G(z) exposure level could predict permanent flight duty limitations (FDL) due to spinal disorders during a pilot's career. METHODS: The study population consisted of 23 pilots flying with Gz limitation (max limitation ranging from +2 G(z) to +5 G(z)) due to spinal disorders and 50 experienced (+1000 flight hours) symptomless controls flying actively in operative missions in the Finnish Air Force. Data obtained for all subjects included the level of cumulative Gz exposure measured sortie by sortie with fatigue index (FI) recordings and flight hours during the first 5 yr of the pilot's career. RESULTS: The mean (+/- SD) accumulation of FI in the first 5 yr of flying high-performance aircraft was 8.0 +/- 1.8 among the pilots in the FDL group and 7.7 +/- 1.7 in the non-FDL group. There was no association between flight duty limitations and early career cumulative +G(z) exposure level measured with FI or flight hours. DISCUSSION: According to the present findings, it seems that the amount of cumulative +G(z) exposure during the first 5 yr of a military pilot's career is not an individual risk factor for spinal disorders leading to flight duty limitation. Future studies conducted with FI recordings should be addressed to reveal the relationship between the actual level of +G(z) exposure and spinal disorders, with a longer follow-up period and larger sample sizes.