It has to do with age. I believe age 70 or early 70's is the maximum age for surgery. As it was explained to me, men have two sphincters that control starting and stopping of urination. One is located between the bladder and the prostate. The other is located on the other side of the prostate toward the perineum. When the prostate is removed during surgery the surgeon also takes the sphincter near the bladder. So one is left with only one sphincter to control urination. I am told that at that age a man will have difficulty gaining enough muscle control of that single sphincter to adequately control the stoppage of urination, hence incontinence and diapers. This was the reasoning given to me by my urologist as well as a radiation oncologist at Mayo. So I tend to believe it to be factual and accurate. Hope this helps.