Like crystals in the bladder, diet plays a very important role in
preventing kidney stones, but in this case has little effect in
removing them - that requires surgery.

It is not a complex operation, though of course few operations are
cheap.

In humans there is a method of breaking up stones using very low
frequency sound. The human in place in a bath of water that allowed
the sound to pass through to hit the stoned just like a sonic hammer,
without damaging tissue in the way. I don't know whether cats have
ever been given this sort of treatment.

If your vet reckons there is little he can do then please, find
another vet for a second opinion.

hi chris,
              i would suggest you get the opinion of another vet !
               my own cat {connor} had surgery,,  he actually had a blocked
penis with stones,, it was brilliant how he recovered .
i cant remember the proper spelling for the procedure,, A URITHSECTOMY ????
IF I FIND MY CAT MEDICAL BOOKS I WILL LET YOU KNOW . REGARDS TERRY KERR
DERBYSHIRE  UK