Old Jersey Wooly w/Chronic Urine Soaked Backside

I've had my bunny for 8 years, although I'm pretty sure she was already full grown when I got her, so there's no telling just how old she might actually be. Anyway, it wasn't until recently that I've started noticing her hopping around w/her haunches all hiked up in the air. That's when I discovered that her whole under side was soaked with urine and she had poops matted in her hair as well. I tried doing the whole dry corn starch deal but all that ended up doing was paper macheing her mats to her butt. And shaving the area didn't pan out because her angora type fur is so wispy the clippers just pushed it flat rather than catching the hairs. So I was forced to go against all recommendations and give her butt a bath. I was very careful as far as making sure she didn't throw her back out or suffer from hypothermia. In fact, it seemed to work out far better than I anticipated! But then the very next day, it was right back to square one again. So far, I've been forced to resort to this on 3 different occasions. I read somewhere that this might just be a part of getting old. What do you think? And is there something else I should be doing? Please help! Its a source of constant stress in both of our lives.

There are several things that it could be. It could be due to old age and her developing arthritis and/or spondylosis, making it difficult for her to assume the proper position for urination as well as difficulty reaching down there to clean herself. In which case she may benefit from daily metacam(after a blood test checking organ function is ok) to reduce inflammation and pain, or Adequan has also been found helpful for arthritis in rabbits. It could be she has developed a urinary tract infection and needs antibiotics. Or she may have bladder sludge and needs her bladder flushed as well as diet change and possibly meds. Kidney problems are also a possibility. What ever the cause, she will need diagnostics done to determine what may be going on. It may be as simple as a urinalysis to determine if she has a UTI, or she may need blood tests and xrays as well. I would suggest booking an appointment with your vet right away, or if you don't have one already, find a good rabbit vet to take her to. The vet can also clip her underneath, so that it is easier to keep her clean and prevent her from developing urine scald if it is an issue where the urinary incontinence isn't going to clear up right away or possibly at all, in which case it will be about management to avoid her developing any secondary skin problems. They can also suggest a barrier cream to protect her skin from the urine.
http://www.bio.miami.edu/hare/urinary.html

http://rabbit.org/vet-listings/
http://www.rabbitsonline.net/forumdisplay.php?f=21

Sometimes butt baths are going to be necessary, especially for rabbits with health problems. It's just best to avoid it if at all possible, but if not, then to make sure it is done carefully and properly to avoid stressing the rabbit and accidents occurring.
http://www.disabledrabbits.com/baths--cleaning.html