Aseptic Necrosis in Adults: Caisson Workers and Others

Abstract

Roentgen examinations of persons who have worked in compressed air, some with a history of bends, or caisson disease, have revealed either single or multiple infarcts in the shafts of long bones, with and without intra-articular areas of aseptic necrosis. The extra-articular bone changes have been found chiefly in the ends of the shaft, either the cancellous or medullary portion, or both. The middle third of the shaft is less frequently involved. Exactly similar changes have been seen in persons—including several women—who have never worked in tunnels or under compressed air and have never been subjected to violent changes in atmospheric pressure. Textbooks describe caisson disease as an acute condition appearing in workers under increased atmospheric pressure, as a result of too rapid decompression. Synonymous terms are bends, diver's palsy, chokes, and staggers. Armstrong introduced the term aero-embolism to describe the condition. Fulton termed it decompression sickness; Hankwitz, decompressed-air illness; End, compressed-air illness; Henderson, aeroemphysema. Musser defines caisson disease as “the disease of caisson workers and divers caused by too rapid decompression, following exposure to increased pressure.” Aviators may also be included, since the swift decrease of atmospheric pressure during ascent is the equivalent of a rapid decompression, except that, quantitatively, nitrogen saturation at 1 atmosphere is considerably less than at increased pressures. Aero-embolism is not to be confused with anoxia. Kahlstrom, Burton, and Phemister state that “caisson disease is the result of injury to the tissues by nitrogen bubbles liberated when the body, which in compressed air has absorbed an excess of nitrogen, is too rapidly removed from the decompression chamber.” They indicate that “chronic lesions sometimes result from caisson disease, the most important being impairment of hearing, paralysis from spinal cord damage, and disturbances of the bones and joints.” They credit Bornstein and Plate (1911) and Bassoe as being the first to describe joint lesions in caisson disease. Bassoe also observed lesions in cancellous bone remote from joints in 3 cases. According to Behnke, bone changes have not been observed in deep-sea divers. Air is composed of approximately 20.9 per cent oxygen, 78 per cent nitrogen, 0.04 per cent carbon dioxide, and 1 per cent of inert gases. According to Boyle's law, a given mass of gas varies inversely as the pressure, the temperature being constant; as the pressure rises, the volume decreases, and vice versa. When a person is subjected to increasing atmospheric pressures, the absorption of gases is increased.