the other question to worry about is whether your diabetes was really since 8y, as it tends to be present before the time of diagnosis.
long standing uncontrolled diabetes will cause neuropathy as well as endothelial damage to the vessels, that's why the medication you have tried didn't work 100%,
as your urologist will explain to you , surgical arm( prosthesis) will not be better as wound healing problem will be as issue.
try to have your blood glucose controlled. have a healthy diet & lifestyle..