UMC OFFERS "MEANINGFUL RECOVERY" FOR PERIPHERAL NERVE INJURIES

Although humans cannot grow a lost foot or hand back, the species has the ability to regenerate nerves, if the conditions are right, according to Dr. Robert Tiel, professor of neurosurgery at the Medical Center.

“The peripheral nervous system is that part of the nervous system which lies outside the brain and spinal cord,” Tiel said. “Most people believe that human beings have little capacity for regeneration after injury. While this is often true, there is much investigational work being done in the area of nerve generation and regeneration.” When a nerve gets severed, it retracts, and intervening scar tissue represents an insurmountable barrier to recovery.

“This is why we repair sharp, acute injuries like knife or glass wounds immediately by re-opposing the severed ends so that the regenerating nerve fiber is not impeded by excessive scar tissue,” Tiel said. “We now have artificial nerve conduits that allow as much as a two-centimeter gap to be spanned successfully in this acute setting.”

When a nerve is injured over a distance by a sudden stretch, as in a motorcycle accident, causing an extreme flexion of the head to one side and the shoulder depression simultaneously, the nerve may tear away from the spinal cord anywhere from four to 10 centimeters. 

“In those cases,” Tiel said, “we explore the nerve after a three-month wait to allow for spontaneous recovery.” He said they observe any recovery through surgical examination.

“We can test whether the nerve can conduct electrical signals,” he said. “If not, we cut out the damaged segment and substitute nerve grafts which have been taken from the patient’s leg and use them to serve as natural conduits for the regenerating nerve.”  

Tiel said this process offers a 50 percent chance of meaningful recovery of function in the damaged nerve element.

“A gunshot injury is another example of a stretch injury,” he said. “Usually the nerve is violently ‘pushed’ away from the trajectory of the missile, rarely transected. We wait four months and see if there is spontaneous recovery. If not, we then explore the nerve.”

Another medical condition Tiel treats regularly is called an entrapment neuropathy. 

“These are areas of relative normal anatomy where the space originally given to the nerve proves inadequate over time,” he said. Carpal Tunnel Syndrome is a prime example.

“Carpal Tunnel Syndrome patients can get relief with a timely transection of the transverse carpal ligament, which has compressed the median nerve at the wrist,” Tiel said. In his practice, he usually sees more challenging patients with less well-srecognized entrapments or those people in whom prior surgical releases have failed to provide relief.

He also treats tumors which arise completely within the substance of a nerve, often in difficult locations such as the spinal column, brachial plexus and pelvis. With careful dissection, he is usually able to remove the tumor without causing clinical damage to the underlying nerve. 

Peripheral nerve surgery is no new kid on the block. It’s been around, but improving, since the 1880s, according to Tiel.

“The advent of antibiotics greatly advanced the field as infection-induced scarring practically eliminated the likelihood of successful regeneration and recovery,” he said. “The use of sural (calf of the leg) grafting was popularized in the 1970s, and further refinements such as microsurgery, finer sutures, better magnification, and illumination have all contributed to the better results in this field.”

While at Louisiana State University, Tiel was part of pioneering the use of intraoperative testing of recovering nerves so as to determine with better probability whether a damaged element was likely to recover spontaneously or needed surgical resection repair. This experience gave him confidence in evaluating new procedures already proven elsewhere.

“It is difficult to pioneer new surgical procedures in the U.S. due to the regulatory process required for scientific investigation,” Tiel said. “As a result, most innovative surgical techniques for nerves are being developed in Southeast Asia or in Europe and then adopted here in the U.S.”

Ongoing breakthroughs in nerve regeneration offer hope to the patients successfully treated, and pride for the doctors who treat them.

“The payoff is in helping our patients,” Tiel said. “In addition, there is great reward in teaching our students and residents about the peripheral nervous system so that when they become practicing physicians, they can more readily diagnose and appropriately treat the surgical problems which arise there.”

—Dani Edmonson (10-22-07)

2007-10-19 00:00:00 17454