Bless you for taking such good care of your girl! 14 years! Wow!
I don't have any real experience with the problem she's having but I wonder if hydrotherapy or acupuncture might be beneficial? A lot of the clinics out here offer at least acupuncture and it seems to work for some cases of nerve dysfunction. Maybe some of them in Jersey do, too. If you can find a place that offers hydrotherapy, it might help strengthen the muscles in her hindquarters and maybe that would revitalize the nerves, as well.
one of our members will come along with some advice from experience soon.
And welcome to the board, cajmartinez.