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Facial Pain (Trigeminal Neuralgia) Dr. Marcus Keep with St. Francis Healthcare System of Hawaii Moderator: Hello and welcome to this afternoon’s Q&A
discussion "Facial Pain (Trigeminal Neuralgia) & Gamma Knife
Treatment" with Dr. Marcus Keep. Dr. Keep is associated with St.
Francis Healthcare System of Hawaii, where he is neurosurgeon. The
Gamma Knife Center of the Pacific is located at SFMC, which is one
of the two hospital facilities of the St. Francis Healthcare System.
Dr. Keep is Fellow in Neurosurgery to the Royal College of Surgeons
of Canada. He is a member of numerous scientific organizations
including the American Association of Neurological Surgeons, the
Society for Neuroscience, the American Epilepsy Society, the
American Society for Neural Transplantation and Repair, and the
Leksell Gamma Knife Society. His special interests are in functional
neurosurgery, which includes epilepsy, Parkinson's and pain. To
submit your questions type them in the send box at the bottom of
your screen and click the send button. We will field questions
throughout the entire hour of this discussion. Without further
delay, Dr. Marcus Keep... Dr. Keep: Hello. I am Dr. Marcus Keep. I am a neurosurgeon in
Hawaii with an interest both in gamma knife and facial pain
particularly trigeminal neuralgia. We have had a gamma knife here
since December 1998 and in the past year and a half we have treated
40 people with trigeminal neuralgia with quite good results. I want
to share this information about trigeminal neuralgia and how it can
be treated with a much less invasive modality with the gamma knife
to anyone who is interested. There are a number of very good trigeminal neuralgia Internet
resources that anyone who has the disease can refer to such as
facial-neuralgia.org and the trigeminal neuralgia association.
Trigeminal Neuralgia as probably everyone who is tuned in today is
aware is a very debilitating facial pain syndrome. The most typical
part of the pain is that it is a sharp severe lancelating
sometimes-electrical pain. The pain is usually localized t one side
of the face usually in one of the three dermatomes of the face. V1
dermatome is the area of the upper part of the eye and the forehead.
The v2 dermatome or maxillary is the area of the check down to the
upper lip while V3 or the mandibular involve the lower teeth and
jaw. More frequently the pain is on the right side of the face and
involve both the V2 and V3 distribution. More women than men suffer
from trigeminal neuralgia. It is a disease that usually starts after
the age of 50 with 63 years old being the average age. The cause of
the pain is thought to be a compression of the trigeminal nerve or
facial sensory nerve where it enters the brain stem on the palm.
Usually, it is an artery branch called the superior cerebella
artery. As we age, this artery keeps growing so that by the time we
reach 50, the artery now is a bit longer and starts to push on the
nerve where previously it never did. Then the artery is compressed
against the nerve and with every heartbeat there is a pulsation that
pushes on the nerve. It is thought that these pulsations cause
patchy demyelination. This allows for abnormal cross talk between
normal sensory fibers and pain fibers in the nerve. It is a bit like
a transpacific fiber optic cable with a shark chewing on it at the
bottom of the ocean. Some of the message that are meant to go to one
sector are short circuited and go to a different one so a normal
telephone call that is misrouted to an emergency sensory creating
the wrong message that there is a painful stimulation. This pain can often be controlled with tegretal, an anti
convulsant drug that reduces this sort of short circuit between
neurons. If tegretal does not work, there are a number of surgical
options, which can help. The first surgeries were performed over 100
years ago though with high risk of damage or death. Now there are
several surgical procedures, which work, quite well and which is
reasonable safe. The best surgical procedure is microvascular
decompression and this is a classic operation developed by Dr.
Jannetta in Pittsburgh. This is an open neurosurgery where the
neurosurgeon will put insulation between the artery and the nerve so
that the nerve is no longer irritated. This surgery works well with
over 80 percent of people getting relief from trigeminal neuralgia.
The effect is quite good for a long time. Typically 70 percent of
people will have pain relief even 10 years later. However, it is
open surgery with the risk of anesthesia, bleeding, spinal fluid
leak and cranial nerve complication. Another procedure that is less
often used now is radio frequency thermocoagulation where a needle
is put through the cheek and into the nerve at the base of the
skull. The tip of the needle is activated which heats up the
ganglion and can produce relief from the pain. However, the high
rate of complication of especially sensory loss in the face and
another terrible facial pain syndrome called anesthesia dolorosa
makes this nearly an absolute procedure. Other similar procedures
involving a needle through the cheek that have fewer complications
are glycerol injections and balloon compression. In the early 90s
there was a return of interest to using the gamma knife to try to
treat trigeminal neuralgia. When the gamma knife was first developed
in the 1960s in Sweden Dr. Leksell used it to treat some cases of
trigeminal neuralgia with good results. In the early 90s especially
at the Uninversity of Pittsburgh, Dr. Kondziolka revived the
procedure but used a new and better location of the nerve to target.
He targeted the retro-gassariam ganglion. This part of the
trigeminal nerve has central myelim made by oligodemvrocytes which
when damaged do not regenerate well. This allows a treatment with
the gamma knife to have a long lasting effect. More peripheral
lesions in the ganglion and the face have myelim made by Schwamm
cells, which can regenerate causing a return of the pain. The gamma knife treatment is a one-day session, actually a half a
day session. The day starts with numbing the top of the head with 4
injections of zylacaine with 2 above each eyebrow and two at the
back of the head. Once the top of the head is completely numb, a
metal rectangle is attached to the head with the use of four metal
pins that look like sharpened pencils. These pins go through the
skin and into just the outer part of the skull. They do not go
through the skull. Once the frame is firmly attached to the skull,
then the person will have an MRI and a CT scan. Some centers will
use only an MRI or possibly only a CT scan for improving accuracy of
targeting; our center at the Gamma Knife Center of the Pacific uses
both. Once the images are obtained, the person can rest comfortably
with family or friends while the neurosurgeon radiation oncologist
and radiation physicist work together as a team on the computer. We
localize the nerve that is causing the pain and place a 4 mm shot of
radiation on it. Different centers will use different doses of
radiation, but most choose a dose between 70 and 95 Gray. Our center
is currently using a dose of 80 Gray. Some innovative programs such
as at Pittsburgh are looking at placing two shots along the length
of the nerve. The location that has been targeted since the early
90s is the area just anterior to the brain stem. More recently work
in Europe is showing promise with a target further out on the nerve
closer to the cassarian ganglion itself. Once we have confirmed that
we have good targeting of the nerve in multiple views and are
satisfied that the brain stem is not in any danger from the
radiation then we printout the plan. We then go get the patient and
take them into the gamma knife room. Of course this whole time the
patient is awake, talking with us and usually comfortable. The
patient helps by walking and sitting on the gamma knife couch. The
gamma knife itself can be seen on our website at the Gamma Knife
Center of the Pacific or one of the other gamma knife centers around
the country. Basically, the gamma knife unit looks a little like an
MRI machine. There is a couch to lie down on and the frame on the
head is attached to a helmet, which will focus the radiation beam
just onto the trigemninal nerve. The person goes into the gamma
knife. The gamma knife radiation is from the decay of cobalt so
there is no noise, no electricity, no light, heat or any indication
that a treatment is being received. The treatment time is about 30
minutes though it can be up to an hour in some centers that have
been in operation longer. At the end of the half hour, we take the
stereotactic frame off the person’s head; apply some polysporin
ointment and Band-Aids on the forehead. After another 15 minutes of
observation, the patient can go home. This whole process takes less
than 4 hours. The person will follow up with their neurosurgeon in
about one week’s time. They will continue taking their tegretal
until the pain goes away. The range of time for the pain to go away
varies from 1 day to 3 months, but typically the pain goes away in
one month. How many people are actually helped by this non-invasive and safe
treatment? About 50 percent of people getting this treatment for
trigeminal neduralgia will be completely free and off of all pain
medications and the additional 30 percent will have their pain
reduced in half but still have to take pain medications. About 20
percent will not get relief from their pain. So about 80 percent get
a significant or complete improvement in their pain. Of the people
who get pain relief, 10 percent of them can get a return of their
pain. If this happens, a repeat gamma knife treatment usually gets
rid of the new pain. What are the complications or side effects of
gamma knife surgery? The answer is remarkably few side effects. The
worse side effect is the 20 percent chance of not getting any pain
relief. There is a 10 percent chance of getting some parasthesias or
a funny tingling feeling on the side that was treated. There has
never been reported a case of anesthesia dolorosa. The pin side
through the scalp usually heals up without any problem in several
days and there is no need for a suture. A small number of people
will report that the skin around the pin will stay numb for 1 or 2
months. We have not seen any infection of the pin sites in our
center. Usually, people that have gamma knife for their facial pain
are surprised at how easy and painless the procedure is. The
introduction of gamma knife, since the early 90s, has remarkably
changed the treatment for trigeminal neuralgia. Very few radio
frequency lesions are being performed and more and more gamma knife
radiosurgeries are being performed. While currently the
microvascular decompression or open neurosurgical procedure putting
insulation between the artery and the nerve is the gold standard for
patients who are under 65, it may well be that soon the gamma knife
procedure will become that gold standard. Certainly if someone is 65
or has any condition that puts them at risk for surgery, gamma knife
is the procedure of choice. Especially because the bad side effects
of gamma knife are so few, it makes the gamma knife very attractive. Guest2: What are the most serious side effects from the gamma
knife. 2 years ago I had gamma knife for trigeminal neuralgia and I
have numbness in my face since then is that very common? Dr. Keep: About 10 percent of people will report some numbness in
their face. If they have had another procedure before the gamma
knife such as radio frequency lesion or even a MVD, then the chances
of numbness are higher. To my knowledge, no one has had complete
loss of sensation in his or her face after gamma knife. Guest7: Dr. Keep, can you tell me what the requirements are to
considered for GK? Dr. Keep: The most important requirement is that your facial pain
be truly trigeminal neuralgia. There are many causes of pain in the
face, which are not trigeminal neuralgia, which might not be helped
by GK. This includes TMJ, dental problems, temporal arthritis,
glossopharyngal neuralgia, post herpetic neuralgia and migraines.
Your neurologist or neurosurgeon should be able to make a diagnosis
of trigeminal neuralgia and if that is what is actually causing your
facial pain, and then you would be a candidate for the treatment. If
you have trigeminal neuralgia there would not be a contraindications
with treatment with GK. Guest2: To Dr. Keep. Every doctor says I have classic TN, but I
have undergone a failed MVD, and a failed RF. The second RF, with a
much bigger lesion did work for about 2 years, but now I'm back on
tegretol. Only 200 mg /day right now seems to be working. At some
point I presume I'll have to consider surgery again. What is the
outlook for success with a GK when someone has had several prior
procedures? Dr. Keep: Any TN that is not successfully treated the first time
always seems more difficult to treat with later procedures. Maybe it
is an effect of the first operation or maybe it is just a tougher
type of TN to treat. I am glad that you are getting good relief now
on a low dose of tegretal. If the pain returns and cannot be
controlled with the tegretal, there are other medications that you
could try after you speak with your neurologist or neurosurgeon.
These medications are neurotin and trileptyl. The neurotin has very
few side effects and is generally very well tolerated. It is worth
trying. Trileptal is a metabolite of tegretal and seems to have
fewer side effects and allows a higher dose to be taken. Trileptal
has only recently been introduced so it remains to be seen how
effective it will be in trigeminal neuralgia, but we are beginning
to place our patients on trileptal prior to treating them with the
gamma knife. If medications do not work for you then you in your
particular circumstance needs another procedure, there is no
contraindication to your having a GK. We have treated at our center
people that have previously have MVD and RF with good result. So if
you have had MVD and RF previously you still would be a candidate
for GK for your TN. Moderator: Unfortunately we have run out of time. Dr. Keep would
you like to make your closing remarks? Dr. Keep: I have enjoyed having the opportunity to talk about one
of my favorite subjects both the relief from pain and getting that
relief through a remarkably painless procedure, gamma knife. I hope
those of you who are suffering from TN will be in those lucky 80
percent who get very good relief from your TN from the gamma knife.
Those that have other types of pain syndromes, potentially some of
them can be treated in the future with gamma knife but for now
trigeminal neuralgia can be very happily treated with this safe, non
invasive and reasonably comfortable procedure. Thank you. Moderator: Thank you for joining this afternoon’s discussion
"Facial Pain (Trigeminal Neuralgia) & Gamma Knife Treatment"
with Dr. Marcus Keep. Dr. Keep is associated with St. Francis
Healthcare System of Hawaii, where he is neurosurgeon. The Gamma
Knife Center of the Pacific is located at SFMC, which is one of the
two hospital facilities of the St. Francis Healthcare System. Dr.
Keep is Fellow in Neurosurgery to the Royal College of Surgeons of
Canada. He is a member of numerous scientific organizations
including the American Association of Neurological Surgeons, the
Society for Neuroscience, the American Epilepsy Society, the
American Society for Neural Transplantation and Repair, and the
Leksell Gamma Knife Society. His special interests are in functional
neurosurgery, which includes epilepsy, Parkinson's and pain. Thank
you all once again for joining our chat. Have a nice day! Reviewed by Steven J. Adashek, MD, FACOG, July 1, 2000 Copyright 2001 Americasdoctor.com, Inc. All rights reserved
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