SAN FRANCISCOA new surgical method for reversing facial
paralysis in brain tumor patients (see photo) will be reported at the Ninth
International Facial Nerve Symposium taking place July 29 to August 1.
Philip J. Miller, MD, and J. Thomas Roland, MD, of New York
University School of Medicine, modified an older procedure in which the distal
facial nerve is rerouted to the healthy hypoglossal nerve fibers. This allows
the nerve axons from the hypoglossal nerve to grow into the facial nerve.
The procedure has restored facial expression in 6 patients
treated during the last 18 months at New York University Hospital, Dr. Miller
said. "The more we do it, the more excited we’re getting," he told ONI
in an interview. It takes 9 months for new nerve fibers to grow and animate the
facial nerve before a procedure can be deemed successful, he said.
Most of the patients had acoustic neuromas or meningiomas. Dr.
Miller said that the procedure, called direct facial-to-hypoglossal anastomosis
with parotid release for facial reanimation, could be used in response to any
condition or treatment that leaves a "structurally intact but electrically
bad facial nerve."
Although technically complex, the new procedure is safe and
offers advantages over jump grafts in which portions of nerves near the leg or
ear are used to connect the facial nerve to the hypoglossal nerve, Dr. Miller
said. With only one nerve connection instead of two, it reduces the risk of
failure.
In addition, it does not introduce any sensory deficits from
the harvesting of nerve grafts elsewhere in the body. "We’re not
creating any new problems," he said, noting that an early technique, no
longer used, completely sacrificed control over the tongue and activities such
as eating in order to regain facial expression.
Dr. Miller said that the first part of the new procedure is
performed by Dr. Roland, a neuro-otologist and skull-base surgeon. Dr. Roland
peels the facial nerve from the bone, releasing it as close to the brain as
possible. As a result, the facial nerve is almost long enough to reach the
hypoglossal nerve.
Normally, the facial nerve enters the parotid gland where it
exits the skeleton. Dr. Roland slices the parotid gland in half so that it dips
down far enough for the facial nerve to reach the hypoglossal nerve, which is
then partially severed. Some, but not all, of the hypoglossal nerve’s fibers
are then spliced to the facial nerve.
No function is lost in the tongue, Dr. Miller said. "More
than 50% of fibers in the hypoglossal nerve continue to provide function to the
tongue, and that’s more than enough," he said. He added one caveat:
"You don’t want to create a splice in the hypoglossal nerve where nerve
fibers going to the tongue and neck are together. Even though the wedge takes
less than 50% of the hypoglossal nerve, you could theoretically be cutting out
90% of nerve fibers going to the tongue."
The procedure averages about 3 hours, but can be done more
quickly if combined with cancer surgery that exposes the bone. The patient
could spend substantially more time on the operating table, however, depending
on how much additional facial work is done by Dr. Miller, who specializes in
facial plastic and reconstructive surgery.
Gold Weights on Eyelid
For example, he usually adds gold weights to the upper eyelid,
so that the patient can close it while waiting for the nerve fibers to re-grow.
This is done, Dr. Miller said, to prevent complications such as dry eye
syndrome, corneal ulcers, and blindness.
To date, the new method has resulted in "a high degree of
patient satisfaction, facial tone, mobility, and protection in all cases,"
Dr. Miller said. "We will continue to find out exactly how far we can take
this. How long after the injury can this still work?"