Can existing saline breasts implants be refilled to their original size?

Unfortunately, implants cannot be refilled. After 10 years, it is likely they need to be replaced. A nice option is to go to held.An exam and consultation with a plastic surgeon is recommended to discuss your options and expectations.

If you have gone from a 36C to a 36A without gaining any weight, most likely your implants have deflated.  Once saline implants have deflated they need to be replaced and cannot be reinflated.  Another consideration would be to consider switching to silicone implants. Your original implants may be covered under warranty.  I would discuss this with your plastic surgeon or the implant manufacturer.    

If your saline implants deflated, then they need to be replaced.  It is up to you to decide if you want to go with saline or silicone. Good luck.

From your description it sounds like your implants might have leaked.  I would suggest you be evaluated by a board certified plastic surgeon.  Your implants might still have a warranty. Good luck!Dr Rast