Food for dog on c/o diet?

My Lhasa Apso/miniature poodle had surgery in November to remove a bladder stone that was 2/3 the size of his bladder. (I adopted him that month, so it was a very busy first month together.) After the stone was analyzed, my vet told me that he needed to be on the c/o diet. He eats the dry food and seems to do very well--no more straining to urinate, and he has a lot more energy now.

My question is: can he eat other things besides the c/o diet and treat? I'd like to be able to offer him other treats if I can. Are there any that are safe for him?

[Dan Sims, DVM]

Struvite stones are caused from chronic infection and calcium oxalate
stones are nutritional in origin.Struvite stones should be treated with 8 weeks of antibiotics
and calcium oxalate stones are treated with a change of diet.
Regardless of which stone we use SO diet canned to help maximize water intake.
I would be strict and not give any treats to avoid future surgeries.