PROPOSED ETIOLOGY OF DYSBARIC OSTEONECROSIS

John Paul Jones, Jr., M.D.
Diagnostic Osteonecrosis Center & Research Foundation
Post Office Box 735, Kelseyville, CA 95451

Over 50% of native diving fishermen can be affected with dysbaric osteonecrosis (DON). These divers breathe compressed air for an extended time at deeper depths, and then rapidly ascend. Autopsies of these diving fatalities, with corroboration from experimental studies, have provided new insights into the etiology of DON.

Current evidence will be reviewed which suggests that DON occurs under the following conditions: (1) abundant fatty marrow, (2) prolonged exposure to compressed air, either in a single long hyperbaric exposure ["saturation or semi-saturation" dives] or extensive repetitive exposures [deep "bounce" dives], (3) rapid decompression, which produces expanding gas bubbles which disrupt marrow adipocytes, (4) presumably causing a sudden increase in local intramedullary pressure, and (5) these marrow bubbles [along with platelets, fibrinogen, embolic lipid, tissue factor, and vasoactive substances] activate focal and disseminated intravascular coagulation with intraosseous thrombosis. When acting in concert, these five factors most likely cause an ischemic bone infarction.