An 87-year-old Texas man has had an unusual surgery to save a hand that was badly burned in an accident.

Doctors sewed Frank Reyes' hand to his belly and left it under a pocket of tissue for three weeks to give it time to heal and form a new blood supply.

Casey Reyes struggled for a way to explain the "sci-fi" surgery doctors were proposing to save her grandfather's hand.

"They're gonna put your hand inside your stomach, kind of like a hoodie," she told him.

Mr Reyes agreed to the strange operation at Houston Methodist Hospital. On Thursday, doctors cut his hand free of its temporary home and shaped some of the abdominal tissue and skin to cover it.

Mr Reyes hopes for near-full use of the hand he almost lost after a freak accident earlier this summer while he was changing a tyre.

"It's a funny feeling," he said in an interview while his hand was still attached to his belly. "Anything to get me well."

Surgeries like this - temporarily attaching one body part to another, or tucking it under skin - are by no means new, but they are uncommon. They are used on the battlefield, in trauma situations, and increasingly in research as a way to incubate lab-grown body parts.

Dr Anthony Echo, a plastic surgeon at Houston Methodist, thought of it when he saw Mr Reyes, a retired cattle ranch worker and school bus driver who lives in Missouri City, Texas.

Mr Reyes was home alone one day in late June, changing a tyre on a trailer, when the jack slipped, pinning his hand against a fender. It was very hot that afternoon, and it took half an hour for help to arrive.

The hot metal was like an iron and "just cooked his hand," burning through a thick glove and through skin, tendons and tissue, Dr Echo said. Doctors initially tried a conservative approach, cleaning and bandaging the wound, but infection set in and most of his index finger had to be amputated.

Still, the hand grew worse.

"His skin was almost completely dead," his granddaughter said doctors told her. "They said it looked like mummy skin."

Mr Reyes was sent to Dr Echo, who realised a skin graft or flap of tissue from another part of his body would not work. The damage was down to the bone, and without a good blood supply, a graft or flap would die, he explained.

The doctor decided to try tucking the hand inside Mr Reyes' belly.

"The abdominal skin actually sticks to the hand" and new blood vessels form to connect them, he said. Without this, it was "likely he would have lost all of his fingers," he added.

Mr Reyes said: "As soon as I'm well enough to drive I want to take a little trip."