Hello Jack,
I had the fistula last year. Mine was a bit more severe - I was actually getting some feces through the penis right after my RRP. The doc kept me catheterized for two months, but after having the catheter removed, I began to get gas (penis farts) .
The catheter went back in for another month, and I was placed on a "low residue" diet. That meant no roughage at all, no nuts, no whole grains, a very bland diet. Consequently I ended up gaining weight because I could eat ice cream, so feeling sorry for myself, I did that a lot.
After the catheter was finally removed, I had one more episode of gas, but convinced the doc not to re-catheterize me. He had told me that if it wouldn't heal on its own, then I would have to have another surgery. He had done hundreds of DaVinci's, and had seen this only once before. On a recent office visit, he told me that he had another one. He said that it was caused by a suture not holding.
Anyway, it's all healed now. But after all the catheterization, I had some muscle atrophy, and have had a "hard time" (excuse the pun) with both continence and erectile function.
Hope it all goes well for you.
-Charlie