Transplant Basics
The first step in preparing for nerve transplantation
is to identify precisely where the nerve damage has
occurred. Doctors do that using a variety of imaging
techniques, clinical exams and other tests, such as
electromyography.
Once they know
where they need to insert the transplanted nerve, they
first look for a way to harvest one from the patient.
"The sural nerve runs down the back of the leg,
just under the skin--we joke that it is God's little
gift to microsurgery," comments Dr. Elkwood. "It
is a small, straight, long, good-caliber nerve, and
its only function is to give some sensation to the outside
of your ankle. Almost every procedure starts out with
the harvest of the sural nerve."
The transplanted
nerve segment is attached using microsurgery. "All
nerve surgery is microsurgery," says Dr. Elkwood.
"The nerve endings are so small and they need to
be sewn in such a precise way that you have to have
magnification to do it properly. We use a suture that's
finer than a human hair and a glue made from cow's blood
that has the consistency of a fried egg."
Sometimes, however,
the sural nerve is not long enough to provide a bridge
between damaged nerve endings in, say, an arm or leg.
"A living donor, such as a relative, is the next
best choice," says Dr. Elkwood. "Cadaver donors
can also work quite well.
"Even if
a transplanted nerve is someone else's, over time the
recipient's body will replace the outer insulation on
that nerve with his or her own. The body makes that
graft a part of itself. So, although we do need to give
people immunosuppressive drugs for the first year or
so after a donor transplant, eventually they can stop
taking them. It's pretty neat."
Reproduced
with permission from Diabetes Focus, copyright Medizine
Inc. 2006
