Surgeon "Grows" Bone to Create Thumb

PHILADELPHIA -- Eating. Writing. Bathing. Driving. Talking on the phone. Playing your favorite sport. All simple tasks, yet virtually impossible without the use of a thumb.

George Johnson was just nine years old when an accident with a firecracker caused him to lose most of the thumb on his right hand. Harold Mosley's thumb was crushed during an on-the-job accident. Stories like these are quite common and usually result in complete loss of use of the injured hand.

Dr. Amit Mitra, chief of Plastic and Reconstructive Surgery at Temple University Hospital, has created an innovative approach to reconstructing hands after such accidents. He uses a distraction device, an object generally used by oral or orthopedic surgeons, to literally grow new bone that can function as a thumb.

Distraction devices themselves have been used in jaw or leg bones for quite some time, but, according to Mitra, even the manufacturer of the devices was not aware that they were being used in the hand.

"If there's one finger you cannot function without, it's the thumb. If it is injured or amputated it is very difficult to use the hand without reconstruction," says Mitra.

"Without your thumb, you lose all capability to grasp things, which makes your hand useless," explains hand therapist Laura Walsh, who works to help patients function after reconstructive surgery.

After an accident like Johnson's or Mosley's, physicians usually try to use another body part, often a toe, to fashion a make-shift thumb. Such a correction allows at least partial use of the hand, but the patient is left with a hand that will always look odd. For someone as young as Johnson, having a toe in place of a thumb could subject him to teasing for many years. A patient like Mosley, a machinist, would never be able to return to work.

When Mitra sees a patient who has lost or injured a thumb, he implants a distraction device into the remaining metacarpal bone using four pins. A telescoping system is secured on the outside of the hand to fix the bone externally and a metal bar secures the bone to keep it immobile. The implantation procedure takes about 30 minutes. The patient then turns the device every day in order to "stretch" the bone. This stretching technique actually allows new bone to grow and lengthens what remains. Eventually, the bone extends long enough to allow the patient to use the new growth as a thumb.

Besides regaining the use of their hand, patients have an added benefit with Mitra's technique. He stretches skin from the hand over the device as the bone is growing so that the new thumb does not appear all that different from a normal finger. Apart from the thumb not having a nail on it, most people would not easily be able to notice that the hand had been injured.

"The best part about this surgery is the fact that patients can get their lives back. Harold Mosley will be able to go back to work rather than going on permanent disability. George Johnson will be able to do all of the things children do and will not be affected as an adult," says Mitra.

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