Has the pain and numbness down the leg actually been diagnosed as due to the diabetes or is it just assumption. I only ask as one of my work colleagues has a problem with a bulging disk in her back which was putting pressure on the nerve. Shooting pains down the legs, pins and needles much of the time and a certain amount of numb feeling. All of which slowly got worse and the pain was constant until her back was operated on. I am sure there are others here now more about this type of condition and may be able to say if it fits or not, my experience is second hand, but it might be worth checking.