Mel, I don't think you find that as a provable connection. Everyone's incontinence or lack of incontinence is so directly personal to their own bodies.
When thing I didn't see mention on your other thread about penis shortening, was the explanation my own surgeon gave on more than one occassion.
Of course there is the space of the prostate that will no longer be there after surgery, that space depends on the original size and location of the prostate. When the delicate attachment is made of the inner side of your urethra is made to the bladder neck (and this is where you surgeon's skill will really shine if done correctly), the bladder, which has had one of its attachment points by the removal of your prostate, is pulled toward the urethra, and joined together. He said the urethra is not pulled toward the bladder, but the bladder is hinged at this point, and is pulled toward the urethra. The shortening is due to the weight of the bladder acting on gravity, pulling everything inward, thus the appearant shortening of the penis. More of the shaft in its flacid state is pulled inward. I cant say what happens when you use a pump or sex drugs or even injections ,because I never had to use any. But as my penis is filling with blood naturally and becoming errect, its length increases all the way to my pre-surgery length. I am guessing here, but I would imagine similar results when the sex pills work and/or injections work properly.
When you are first coming to terms with incontinence, the "shrunken" penis syndrome can make it more difficult to aim correctly. Especially until you have some kind of real stream again. I would find myself proudly peeing down the front of the outside of a guards, or down the front of my pulled down underwear, because I didn't realize that it was a slow dribble with no force, not even enough force to clear the toilet, lol. I learned fast on that one.
Fortunately, I only had to deal with minor incontinence issues for less than a month, and most of it was in my head, more than my body.
David in SC
Age: 57, 56 dx, PSA: 7/07 5.8, 7/08 12.3, 9/08 14.5, 10/08 16.3
3rd Biopsy: 9/08 - 7/7 Positive, 40-90% Cancer, Gleason 4+3
Open RP: 11/08, Rht nerves saved, 4 days in hospt, on catheters for 63 days, 5th one out 1/09
Path Rpt: Gleason 3+4, pT2c, 42g, 20% cancer, 1 pos margin
Incontinence: 1 Month ED: Non issue at any point post surgery
Post Surgery PSA: 2/09 .05,5/09 .1, 6/09 .11. 8/09 .16
Post SRT PSA: 1/10 .12
Latest: 7/9 met 2 rad. oncl, 7/9 cath #6 - blockage, 8/9 2nd corr surgery, 8/9 cath #7 out 38 days, 9/9 - met 3rd rad. oncl., mapped 9/9, 10/1 - 3rd corr. surgery - SP cath/hard dialation, 10/5 - 11/27 IMRT SRT 39 sess/72 gys ,cath #8 33 days, Cath #9 35 days, 12/7 - Cath #10 in place