Rewiring the body's electrical system
Date: November 1, 2010
Allan Belzberg is no stranger to nerve operations that, as he puts it, “rob Peter to pay Paul.” The Johns Hopkins neurosurgeon has decades of experience borrowing portions of healthy nerves to take over the function of those damaged by injury or disease. Now, he’s taken the concept a step further by using these familiar surgeries to treat transverse myelitis (TM).
Though TM leads to inflammation and scarring only in the spinal cord, these lesions invariably affect the health and activity of associated peripheral nerves. With that in mind, Belzberg concocted a novel way to restore function in TM patients. Rather than focus on the spinal cord, he and his team treat the affected nerves as they would a peripheral nerve injury, connecting portions of dispensable, healthy nerves unaffected by TM to muscles whose original nerves are no longer functional because of the disease.
So far, Belzberg and his team have performed a handful of nerve-rewiring surgeries for TM. In one recent procedure, they used the technique to treat a 6-year-old whose right arm had become paralyzed from this condition. As with most other patients Belzberg’s team has treated with this method, the child has gradually regained some use of the paralyzed extremity, with minimal loss of function affecting the muscle from which a portion of the healthy nerve was taken.
Though the concept of rewiring nerves to treat TM is novel, in most cases the actual procedure is not. For example, Belzberg and other surgeons have performed the same surgery they used for the 6-year-old patient—disconnecting the distal spinal accessory nerve from the trapezius muscle and transferring it to the biceps affected by TM—for other pediatric and adult patients. For one recent case, however, Belzberg and his colleagues designed an entirely new procedure to help a 4-year-old girl whose right leg had been paralyzed by TM.
The team—consisting of neurosurgeons, pediatric general surgeons, pediatric plastic surgeons and a pediatric urologist, among others—took the obturator nerve on the left side, which controls the gracilis muscle, rerouted it across the pelvis and hooked it into the femoral nerve, which controls the right quadriceps. The procedure was so new and complex that the team practiced first on a cadaver to see whether it was possible to perform. They successfully performed the operation on July 8 of this year.
Regardless of the reason for the nerve rerouting procedure, says Belzberg, the physical therapy and rehabilitation team is crucial for improving the chances of a successful outcome. Because the healthy nerve previously controlled a different function, the brain must relearn to use that nerve in its new role. For one of Belzberg’s recent patients, for example, that means gaining a new understanding that when he tries to make a fist, his left arm will bend. This relearning process usually takes six to eight months, during which patients receive aggressive rehabilitation and discover their new capabilities.
Gaining renewed use of a limb that a patient thought was gone forever can be a new lease on life. Belzberg recalls one young man who had normal use of his hand and wrist but couldn’t bend his elbow due to nerve injury.
“He’d told me that we might as well cut the arm off since he thought it was useless, but we were able to give him that arm back through nerve surgery,” Belzberg says. “For the rest of his life, he’ll have a useful arm—that’s an amazing thing.”