Posted by Maddiver on November 27, 2001 at 09:19:26:
In Reply to: Re: Maddiver- what about 'Bone Necrosis'? posted by Steve on November 26, 2001 at 19:49:10:
I have mentioned before that I think it is prudent to get a bone scan (Bone scan -- A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected and travels through the bloodstream. It collects in the bones, especially in abnormal areas of the bones, and is detected by a scanner.) done if you have done many deep air (or even 80-130') dives over the years as a precaution and that the hip area is generally the first place signs show up.
Extrapolating from Dan study on young bone growth it is easy to see the linkages between growth/maintenence and subclinical bubbles of significant size and number.
"concern is focused on the possible formation of micro-bubbles in the bloodstream of all scuba divers. We often call these ‘silent bubbles’, which fail to produce any detectable symptoms, but are known to be present in the bloodstream of many divers. No one knows to what extent these bubbles could form in divers. Theoretically, these bubbles may obstruct blood flow in nutrient vessels to the epiphyseal plates, also called growth plates. This process may cause focal areas of avascular necrosis or angular deformity to the developing weight bearing long bones, particularly the femoral head, distal femur, and proximal tibia"- DAN Web site FAQ section
From American Osteopathic Association peer reviewed journal discussing steriod reaction to pressure reductions in mature rabbits.
The most common feature was evidence of new and old hemorrhage through the sinusoids, exudative reaction and thrombus formation in veins, and small arteries. Focal necrotic areas of bone marrow showed an accumulation of cell debris, residue of hemorrhage and disappearance of marrow elements. The findings suggest that: 1) steroids may potentiate the effects of a preexisting condition to increase the risk of osteonecrosis, 2) immunological reaction may be an important factor in the pathogenesis of necrotic lesions, and finally 3) repeated intramedullary hemorrhage and thrombus formation may represent early major pathological findings in bone necrosis.
The point is that most people under 50 never have any reason to suspect necrosis until it is too late and need surgical intervention. We participate in an acitivity that when done to the extremes (commercial diving) has produced serious consequences at very young ages (36 year old with him replacement) and while we don't do as much or as serious diving (some will obviously debate me on this) the side effects can be viewed over a longer term scale and should be noted and tested for.