I have a completly defective shoulder, due to an injury in the army. I dont exactly understand your problem, but from what I can see I have, among other things something like what you have, also including a reduced blood flow into my hand due to pressure on a blood vessel. I consulted a dive doctor regarding it, and his answer was, that while he admits there may be a slight increase of chance to DCS I shouldn't bother myself with it, as it is very small, and as long as I dive safe it should be well factored inside the tables ( the tables do take some factors in them, as they are ment for the shapiest and the unshapiest). I was also advised to workout as much as I can to strengthen the muscle, so it will hold the shoulder better (what the bone can't do to well).
Now like I said- I am not really sure I know what you trouble is (english isn't native to me) but I do think that the advice I recived is a sound one.