4 yr. old cat leaking urine after catherization for urinary blockage and surgery for bladder stone?

the bladder and urethra are probably still agitated from surgery. if this is the case, they can spasm causing discomfort and leakage. i think if i had bladder surgery, it would take a little time to go back to normal. did the vet put your cat on a prescription diet to prevent the development of future stones and crystals? Hill's Science Diet C/D multicare or Purina U/R are good ones. talk to the vet about this. it is very important or you could end up back at step one in months. the food is a bit more expensive, but cheaper than another surgery.