Edward Bonfiglio was on a routine patrol with a Marine unit in Afghanistan in 2009 when it was hit by small-arms fire and rocket-propelled grenades. A round smashed through the Navy medic's left leg, leaving him unable to move it or feel anything but pain.
A few weeks later, at a military hospital in Bethesda, Md., Mr. Bonfiglio was given a choice: try a new technique to regrow his severed sciatic nerve, or have his leg amputated below the knee.
"I was pretty adamant about keeping my leg," he said.
Three years and hundreds of hours of physical therapy later, the 26-year-old Mr. Bonfilgio has regained much of the use of his leg. He has graduated from a wheelchair to a cane and can even jog slowly. His leg isn't perfect and never will be, but, he said, "I never saw myself being able to walk with just a brace on my leg."
More than 300,000 Americans suffer severed peripheral nerves in their hands, arms, legs and feet every year, often due to highway accidents or mishaps with tools or knives. Combat injuries also are big contributor.
Traditional nerve repair involves using a piece of healthy nerve from the patient—usually from the back of the ankle. But that requires a second surgical incision and often leaves a numb spot where the nerve was removed.
Some gravely wounded soldiers don't have a lower-extremity nerve to spare. Surgeons also can use synthetic tubes, but they are most effective for repairs smaller than one centimeter (about 0.4 inch).
A new type of nerve graft made from processed cadaver nerves is giving surgeons another option for rebuilding nerves, sometimes in limbs that previously couldn't be saved.
"It has become the standard of care for our group," said Lt. Commander Patrick Basile, director of microsurgery at Walter Reed National Military Medical Center, who operated on Mr. Bonfiglio. Since that operation, the division of plastic and reconstructive surgery there has used the new nerve allografts, as this type of graft is called, in about 20 other patients.
Surgeons are using the allografts to repair nerves damaged in other situations as well, including oral surgery and cancer operations. Houston urologist Kevin Slawin uses them to reconnect erectile nerves when they can't be spared during prostate-cancer surgery.
Not all severed nerves can be repaired. Injuries to the central nervous system, in the brain and spinal cord, are almost always permanent.
But parts of the peripheral nervous system, which facilitates movement and feeling in the rest of the body, can regenerate. The section beyond the break dies, leaving just the original sheath. The other side can regrow into the sheath at a rate of about one millimeter a day. But if there is a gap, the nerve needs a bridge to grow back correctly, or it can create a dysfunctional bundle that causes pain.
Allografts use cadaver nerves that are treated to remove cells and other tissue, leaving hollow nerve channels for the patient's own nerve to grow into. The segments come in a variety of widths and lengths—up to seven centimeters currently.
"We can take the exact size we need out of the freezer," said Greg Buncke, director of the Buncke Clinic in San Francisco, who said the clinic uses allografts almost exclusively now in trauma cases.
Registered for use with the Food and Drug Administration in 2007, the allografts are made by AxoGen Inc., AXGN 0.00% of Alachua, Fla., and have been used to date in about 7,000 patients, according to Erick DeVinney, AxoGen's director of clinical and transplantation sciences. Most have involved nerves that control feeling, but allografts increasingly are being used to repair nerves that control movement as well.
Some veteran clinicians aren't yet convinced that allografts are as reliable as a transfer of a patient's own nerve (known as an autograft).
Surgeons say no randomized trials comparing the two types of grafts directly have been published, but several studies have shown that results with allografts are as good as those reported historically with autografts, and better than with tube conduits, with no complications or rejections.
Using an allograft costs about the same as a tube conduit, and less than an autograft since less surgical time is needed.
"Autograft is the gold standard, so some surgeons don't like to deviate from that," said Steven Moran, an orthopedic and plastic surgeon at the Mayo Clinic in Rochester, Minn. But Dr. Moran said he much prefers allografts to harvesting a patient's nerve. "That's another big incision, another area to heal and some patients get a painful nerve scar on that site," he said.
Repairing Mr. Bonfiglio's sciatic nerve required a five-centimeter graft—the biggest ever used at the time. The nerve had to grow back, millimeter by millimeter, from his thigh to his toes and he had to constantly exercise his leg muscles so they didn't atrophy.
"I wasn't the greatest patient—I was a pain in butt. But I got it done," said the former medic, who now is studying to be a physical therapist himself.
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