Poor girl. Could she be having infections as a result of sludge? My story is perhaps not typical, as I'm in Canada and guinea pig surgery is not as common here as in the UK. One of my pigs (Sundae) had repeat urinary tract infections and was diagnosed with a bladder stone when she was about 2. There was an option to do surgery to remove the stone, but the vet hadn't performed many of them and the cost was very prohibitive (it was about two months of my mortgage, shockingly!) and there was no guarantee that she would not form other stones afterwards. I decided to treat the UTIs that she was prone to due to the crud in her bladder growing bacteria and hope that she got some good quality of life before it all went bad. Fast-forward almost four years and Sundae is still going strong. She is extremely prone to UTIs and as such she is on a suppressive dose of antibiotics constantly (0.3 mL of Baytril nightly.) It keeps the bacterial load in her bladder lower and reduces the number of UTIs. Her discomfort and symptoms (i.e. bladder leakage leading to urine scald, etc.) are secondary to bacterial infections which make her unable to hold it, not the stone itself. She also has no signs of pain like hunching, squealing, low appetite, etc. unless she has an active infection. Despite intermittent flares, she has been a happy girl on suppressive therapy and has now reached old age, something I NEVER thought we would see. It's possible that she may still pass of complications or if we hit a point where she is in pain because we can no longer control the infections. However, she is turning 6 in a week or so and no matter what happens, she has lived into her golden years and I consider the suppressive antibiotics a huge success for her! So it's something worth asking about... I bring it up because Sundae also has leakage, etc.- but only when she has an infection, not from the stones themselves.