I've have good experiences with chiropractic. I have scoliosis and had unrelenting back pain, limb numbness, and sciatic nerve pain until I tried chiropractic. When Keno (who was 5 at the time) started leaking urine, I did an online search for possible causes and came across this info re: nerve impingment and incontinence in dogs:
"A specific example of this situation is when the bladder or sphincter muscles are inhibited leading to incontinence issues in dogs. Misalignments or joint restrictions with the sacrum and caudal lumber joints in particular will decrease the function of the corresponding nerve roots and the nerves that form from them. One particular nerve, the pudendal nerve is formed by the nerve roots from the first three segments of the sacrum. This nerve goes on to branch into other nerves that supply the sphincter muscles that control bladder and bowel function. If this nerve is not functioning properly, it can cause leaking urine or incontinence issues. Chiropractic aims to remove this interference through adjusting the lumbar spine and sacrum. This allows the nerves to be as healthy as possible. When proper nerve function is restored and the brain is able to communicate effectively with this area, certain incontinence issues can be resolved. However, there can be other reasons for incontinence such as infection, disc herniation or tumors so it is important that these issues be addressed and ruled out." Do a search on chiropractic and canine incontinence and you can find other references. I've read about success with acupuncture for incontinence as well but have no experience with it.
Anyway, my vet is also a chiropractor and he commented that Keno seemed sore in his sacral area when he examined him, but he got a urine same to rule out a UTI (it was negative). He adjusted his lumbar/sacral area and the adjustment relieved his pain and incontinence immediately. I'm not sure it always works with a single adjustment, but it worked like that for Keno twice. Several months later I took him back to playgroup and Keno was a complete wild man at playgroup. He ran and played so rough and hard that he hurt his back again and started leaking the next day. Single adjustment fixed it a second time. And I stopped taking him to playgroup.
Oh, and several years ago, a new adopter that I met at a local Petsmart called me and said her young male greyhound had started leaking urine suddenly and a round of antibiotics hadn't helped and asked my advice. I told her about my experience with Keno and she had her boy adjusted and she called me back to say it worked for him.
And here's a link you might want to check out to look at all options:
http://6 Causes of Bladder Problems and Urinary Incontinence in Dogs
Good luck with what ever you decide. I hope you find the cause and can get it resolved.