“There are many moving parts, when it comes to performing procedures as intricate as a toe-to-thumb transfer,” Dr. Alexander Spiess, division chief of hand surgery for the University of Pittsburgh Department of Plastic Surgery, said. “Fine details, such as how you angle your cuts on the bone, can impact the overall function of the thumb. Making a cut a few millimeters in one direction versus another can alter the overall function of the digit, emphasizing the importance of where you position the thumb in space with respect to the patient’s hand.”

Talbot noted that there isn't an easy analogy that explains the difficulty of the procedure, but said, "It is like sewing together a chopped chive with a human hair, but keeping in mind that the goal is to keep an open central lumen while ensuring that the juncture is water-tight."

And since many patients lost their thumbs due to trauma, the tissue that surgeons need to reconnect may not be easy to “hook up,” as Rosen phrases it. In some cases where the thumb was cut clean off, all of the necessary vessels are accessible to the surgeon. Burned, blasted, and crushed hands can make things more complicated.

“I had a kid in Vietnam that had lost all his fingers and he crushed his hand, so I had to hook up his toe. I had to go all the way into the wrist to find a vessel to hook up to,” Rosen said. In order to connect those hard to reach places, surgeons often use a long vein from the toe as a bridge. “But essentially, as long as the patient is alive there’s always a vessel to hook up to. I could always hook it up to the heart,” he said, smiling. “So we’re always going to find a vessel, it just becomes harder and harder.”

It’s not a perfect replacement. The great toe looks different than the thumb, and it functions in ways different than the thumb. And it’s not just the hand that has to heal, the foot does too.

“The worst part of it was taking the toe off,” Colello said, eight months after the procedure. “I lose my balance a lot easier. The foot is still healing. It’s still sore, whereas my hand isn’t. Even coming out of surgery, there was a lot more pain in my foot than in my hand.”

But with time and practice, thoes can become totally functional. Colello said that sensation has improved greatly—much faster than Buonocore expected. “It’s still numb. The feeling’s still coming back, so that’s a little awkward. It makes it feel even bigger,” Collelo said. “The only drawback is that the very tip of my thumb–or what’s replacing my thumb–doesn’t bend like my real thumb, my thumb I was born with.”

Colello noted that he could have another procedure that would allow him to bend his thumb, but that he wasn’t up for it right now. For now, he’s happy with the thoe he’s got and is hopeful that he will retain full sensation.

So while Colello’s thoe isn’t perfect, it’s better than nothing.