Lucas Cruz had both his legs reconstructed following the attack on his birthday. Lucas was celebrating with his family on August 7 before a shark attempted to drag him into the water.
His family managed to pull him back with one doctor who performed the operation on the teenager revealed his calf muscle had been “cut in half”.
Dr Haaris Mir, a surgeon and medical director at the Burn and Reconstructive Centers of America, revealed the shark had left teeth marks on the boy’s bone.
After being dragged back into the boat, the captain managed to tie tourniquets on his legs to try and stem the bleeding.
Lucas later needed four separate surgeries to reconstruct his legs.
Dr Mir revealed the 15-year-old had been lucky to survive after losing three litres of blood.
Dr Mir told People magazine: “He had cuts all the way down to his bone.”
“There were actually teeth marks on his bone in his legs.”
“Initially I thought he had multiple bites but after talking to him, he said he was only bitten once.
“So if a shark grabbed both his legs, from an ankle to the top of his thigh, that is about four feet and it would tell you just how big the jaw was.
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He added: “I kind of just bled out on the boat.
“It crossed my mind that I was going to lose my leg. Luckily I didn’t.
“I feel pretty lucky because they said that there was a good chance I was going to die, but I didn’t.
“So I guess I’m pretty lucky.”
While swimming in the waters in the Ocean Reef channel near Key Largo the youngster said he felt a bump in the waters.
He initially thought it was the boat before realising it was a shark and then attempted to get back to his family.
He said: “I thought it was the boat, but it wasn’t because when I looked above the water there was no boat near me.
“So then I realized it was a shark.”