An 82-year-old tortoise had to have a bladder stone 'bigger than a tennis ball' surgically removed, writes Ed Cullinane.

The elderly tortoise called Joey required the expertise of two vetenary surgeons to remove the massive 150g bladder stone.

However Joey may take up to a year to heal from the surgery after surgeons were forced to cut through her shell to remove the mass.

Tortoise shells are an extension of their rib cages, meaning the vets had to create a fibreglass and resin glue to hold together her shell after the surgery.

Vet Viliam Hoferica, 25, says that the bladder stone was the largest he had ever seen.

He said: "If Joey was a human, it would be like having a bladder stone the size of a basketball.

"It's definitely on the leaderboards of unique issues with exotic animals I've seen. Given the size of the stone, it was very unique."

Viliam, a surgeon at the Rosevean Veterinary Practice in Penzance, Cornwall, says that Joey's condition was only discovered by accident due to tortoises' hardy nature.

The bladder stone may have been growing for months or even years.

He said: "Tortoises are a very tough species. They don't let you know what is wrong until it's really bad.

"Joey had only been acting unusually in the last few weeks before the surgery, and even then she was just eating less and moving less.

"She had been very lethargic, eating less and generally not happy. But thankfully she has very caring owners who noticed something was wrong.

"Eventually we did an x-ray, and luckily bladder stones show up on tortoise x-rays. But it was much bigger than I expected."

Viliam collaborated in the surgery with advanced exotic pet practitioner Pas Medina.

Thanks to their skills, Joey is expected to make a full recovery.

He added: "It was a unique surgery, going through the shell is usually a last resort because of how long it can take for it to re-grow.

"I treat any animal, so having Pascal to help assist me in the surgery with his specialization. It was great to have an extra pair of hands."