The following interview will be published in the Movers & Shakers newsletter
in just a few days.
Since there has been much talk about the pallidotomy, I thought I would put
this interview on the
list server.  Reference to his interview should be
Movers & Shakers Newsletter, YPSN of CA., Vol 3, No. 5, Fall 1994.
 
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Pallidotomy at Stanford University
by Alan Bonander, Leah Schorr, PhD, Jon Stedman
 
This interview is with neurosurgeon, Gary Heit, MD, PhD, from Stanford
University in Stanford, CA.  Stanford University Medical Center will be
starting a pallidotomy program in January / February of 1995.  We thought it
would be informative to interview one of the neurosurgeons to tell us about
the program.
 
Bonander: What is Stanford's interest in the pallidotomy?
 
Dr. Heit: Dr. Gerald Silverberg, senior neurosurgeon at Stanford, stopped me
in the hallway one day.  He             had attended a conference where he
heard Dr. Mahlon De Long(1) talk about pallidotomy.  He asked if I would be
interested in setting up a project for this procedure.  I should give you
just a little of my background first.  Before I became a neurosurgeon I was a
scientist with special interests in cognitive neurophysiology, which deals
with how the mind is expressed by the brain and vice versa.  I have done a
lot of invasive intra-cranial recordings in humans in working on these
various issues.  In the process I had done extensive reading in Parkinson's
disease and associated subcortical dementia.  Dr. Silverberg knew all this,
and coupled with his subtle way of asking, what was I to do?  He is my
mentor.  We had actually talked about this previously, but this time we
researched all the literature we could find.  We had all of Laitinen's(2)
papers, Leksell's(3) paper and even had found papers dating back in the 40's
on a variant of the pallidotomy.  We decided it was a procedure that had
merit.  However, the location of the lesion is in a very precarious location,
between the fibers that control movement and the fibers of the visual tract.
 We decided this is not a procedure that one can read the book and then do.
 We wanted to go somewhere and learn it.
 
Bonander: Whom did you contact and where did you go?
 
Dr. Heit: We looked around and it boiled down to Dr. De Long as our first
choice.  However, we were unable to schedule a time with him at that point.
 We contacted Dr. Robert Iacono(4) of Loma Linda Medical Center and he said
they would love to have us.  Dr. Philip Wasserstein, our neurologist, Dr.
Silverberg and myself flew down to Loma Linda and spent two days there.  Dr.
Iacono is a very technically gifted neurosurgeon.  He has really advanced
this procedure to a high art.  The next thing I knew was I was on my way to
Loma Linda for two months.  For two weeks I just watched.  Then I started
doing the procedure.  I did over 40 pallidotomies under the watchful eye of
Dr. Iacono.  I also did a few thalamotomies.  You might say I have had
on-the-job training.
 
Stedman: You mean hands-on training!
 
Dr. Heit: That is better, I have done this procedure over 40 times and I have
done it with all the nuances Dr. Iacono has worked out over the last three
years.
 
Schorr: Will you be using a CT scan or an MRI scan?
 
Dr. Heit: Early pallidotomies were performed with CT scan.  The problem with
CT scan is it can give
bony landmarks but does not show the fine architecture of the brain.  Today
everyone is using the MRI scan.  Since both scan techniques have errors, it
is important that electrical stimulation(5) also be used to verify probe
location.  This safeguards the patient from the many inaccuracies of
conventional scans.  As a personal comment, I would not have a pallidotomy
without electrical stimulation.  This is a minimum requirement and is key to
proper lesion(6) placement.
Bonander: What is the problem with the MRI scanners?  What is the error?
 
Dr. Heit: Due to construction techniques, the magnet itself introduces a
distortion of the image.  This distortion is on the order of about 5 to 7 mm.
 Now one can partially compensate for this error by doing a characterization
of the individual scanner.  This can, at best, cut the error in half.  Still
the error is very subtle and there are shifts from patient to patient of a
couple of mm.  So for some patients the error could be 3 mm and on others it
could be 9 mm.  Relying strictly on MRI scan is very dangerous.
 
Stedman: This is a very large error for such delicate surgery.  Can't software
 correct this distortion?
 
Dr. Heit: We are a major GE center for MRI research and we have a man who
just finished his Ph.D. doing just that --  removing the distortion in MRI
imaging.  He is now developing the technique for use in our MRI scans.  The
other way around the MRI distortion is to do ventriculography.  This is a
very old technique but it allows accuracy to within 1 mm or better.  In
ventriculography a small amount of contrast is released into the ventricle of
the brain.  A special X-ray is taken using the contrast.  We plan to use this
procedure until the MRI image correction system shows itself to be superior.
 
Schorr: I don't think I have read anything about ventriculography in a
pallidotomy.
 
Dr. Heit: Doctors who understand MRI imaging are aware of the 5 to 7 mm
error.  There was a patient whom Dr. Iacono and I reviewed who had had a
pallidotomy without electrical stimulation, with reliance totally on the MRI
scan for targeting the location of the lesion.  The lesion was in the
internal capsule(7) and the patient became hemiplegic(8) and will stay that
way.  There was nothing we could do.  Relying solely on MRI guidance is very
dangerous.
Dr. Heit: The way the procedure works is: an MRI is taken and then
ventriculography is performed.  We then introduce the probe and do electric
stimulation.  This gives us an idea how close we are with the probe to the
optic tract and to the internal capsule.  From Dr. Iacono I have learned
where I must be with the probe for specific heat levels and duration of probe
heating.   Periodically the probe location is verified using
ventriculography.  This is how Dr. Iacono does the pallidotomy.  We will be
spending time with Dr. De Long's group at Emory in Atlanta.  We may choose to
modify our procedure based on their information.  Our plan is to combine the
best features from both centers to form our procedure.
 
Schorr:  Will you be doing micro recording also?
 
Dr. Heit:  I did a lot of micro recordings when at Loma Linda.  We often
found a lot of hyperactivity in the pallidum; however, sometimes there was no
activity -- a quiet pallidum.  Those patients did well and I do not know how
to explain that.  We will have our own micro recording program to help us
better characterize the pallidum.  This all leads to the basic problem of
patient selection.
 
Dr. Heit: There is not a set of definitive qualifications for selecting the
best candidates for the pallidotomy.  Occasionally, when working with Dr.
Iacono, we would find patients we felt to be ideal for the procedure;
however, after the procedure the improvement may have been marginal for some
of these patients.  Conversely, where we did the procedure on a compassionate
basis, with little expectation for good, the procedure yielded spectacular
improvement for some patients.
 
Bonander: How does Stanford plan to advance the patient selection process?
 
Dr. Heit: Here at Stanford we have a pool of incredibly talented people.  We
have recruited a group of neuropsychologists who have developed both research
and clinical tests to be administered both before and after the surgery.
 This will be used to evaluate change in cognitive function as well as motor
performance. Neuroradiology is doing a number of things to improve our
targeting procedure as well as to develop a precise MRI scan.  They also have
some interesting ideas on using new MRI technology.  We hope their work will
help us better delineate good candidates for the pallidotomy.
 
Bonander: What value is this surgery to those diagnosed as Parkinson's
Plus(9)?
 
Dr. Heit: All indications are that the surgery is of limited value to this
class of patient.  Initially we will not be looking at this group.  We expect
to see patients who have been misdiagnosed and are searching for answers.
 Some of this group may well have one of the Parkinson's Plus diseases.
 
Stedman: Will anything be done post-op for the patients?
 
Dr. Heit: One area of special interest is rehabilitation.  The rehabilitation
staff is ecstatic about the possibilities.  There is a population of patients
with very debilitating Parkinson's disease and, to date, little could be done
for them.  If neurosurgery can reverse much of the dyskinesia, akinesia,
bradykinesia and tremor after maybe ten years of debilitating disease, we
cannot then send them out after surgery and say, "That's it."  There may be a
need for physical, occupational and/or cognitive rehabilitation. One thing we
are doing is designing a comprehensive rehab program.  We have the capability
to help the patient as necessary to re-enter society.  In the long run we
want to become a true movement disorder center.
 
Schorr: This sounds very extensive.  What are the patient requirements?
 
Dr. Heit: We will be asking patients to come for a week of pre-op clinical
and research assessments. A patient will be evaluated by various groups to
assure proper medication and to determine severity of disease.  All staff
members will review the pre-op patient information.  The decision to proceed
with surgery will be made during a group meeting.  After surgery we ask that
the patient stay in the area for a few days.  We want to be near the patient
should questions arise or problems develop.  If the patient needs rehab, they
will be asked to stay in the area.  We will be doing 3, 6 and 12 month
follow-up evaluations and maybe follow-ups annually for many years.
 
Bonander: As much as patients like to think they are making rational decisions
 about surgery, I believe the decision is emotional.  All the rational
thinking happened before contact with the neurosurgeon.  PD patients normally
have not experienced neurosurgery.  I had had an appendectomy some fifteen
years earlier.  That was my surgical experience.  I was very naive when I had
my pallidotomy in Sweden.  I had expectations that were realistic when I
talked about the surgery to others; however, deep down inside me I wanted to
leave all my Parkinson's disease in the OR.  That may have been an unreal
expectation, but it was my unspoken hope.
 
Dr. Heit: Setting realistic expectations for the surgery is very important.
 In the initial evaluation before surgery expectations will be discussed.
 There are risks that need to be understood.  There must be hope for
improvement, no matter what the risks are.  Unfortunately, the pallidotomy is
not a cure.
 
Schorr: All this is great, but it could be very expensive.
 
Dr. Heit: Some of the work is clinical and the patient's insurance will be
billed.  The remaining research will not be billed to the patient. We will
work with the patient and with their insurance company.  Palo Alto is an
expensive area, so we have talked to our social services group about the
availability of low cost accommodations.  This is their area of expertise.  I
know Dr. Iacono has patients coming from all over the world as does Stanford
Medical Center.  Concerns for the logistics are very important to both the
patient and the caregiver.
 
Bonander: How do you view the pallidotomy as a neurosurgical procedure?
 
Dr. Heit: In the scale of neurosurgical interventions it is not a very
technically challenging surgery, but it is intellectually very challenging.
 It is this side that has my interest.  It has a lot of inferential analysis
that requires knowing what you are doing.  Additionally my background as a
scientist makes this procedure interesting to me.
 
Bonander: How does a patient use the services of Stanford University Medical
Center?
 
Dr. Heit: They may call either Dr. Philip Wasserstein's office at (415)
723-6469 or call my office at (415) 723-5572 and tell us they are a
Parkinson's patient interested in our program.  If you call my office and I
am not in you will most likely speak to Melinda Fike, RN, (415) 725-5280.
 Melinda is the nurse practitioner for Parkinson's disease in the Department
of Neurosurgery.  She should be able to explain the program.  You may also
call the Stanford Referral Center at (800) 756-5000.  Recently I had a call
from a lady who said she had just been diagnosed with PD and wanted the
operation that best fit her disease.  Obviously she needed education in the
treatment of PD.  We will be asking some questions on the telephone.
 
Bonander: What about stimulation therapy?
 
Dr. Heit: Stimulation is another area of particular interest to me.  Rather
than placing a lesion as we do in the pallidotomy, an electrical wire is
placed in the appropriate location in the brain.  The wire is connected to a
programmable device that will provide an electric stimuli either on demand or
on a programmed interval.  This is similar to the heart pacemaker in concept.
 Stimulators have been placed in the thalamus, pallidus and subthalamic region
s.  The risks of subthalamic stimulation are too high, but the other areas
are very interesting.  While placing a surgical lesion is irreversible,
inserting a wire for stimulation is reversible.  It is a new and exciting
area that I expect also to research.  In the not-too-distant future this may
also be available to patients at Stanford.
 
Bonander: The San Francisco Bay Area is loaded with molecular technology
firms.  I know Stanford is involved with many of them.  Do you see anything
in the near future from this involvement?
 
Dr. Heit: I am researching a technique that will allow removing a small
sample of tissue just before the lesion is made.  This will be handed off to
the various sciences for further study.
 
Dr. Heit: While at Loma Linda I was stunned at the technical expertise of the
Parkinson's patient.  I met Tony Schoonenberg(10), a parkinsonian, working on
the team.  Tony researched papers written in the 60's and 70's and it was
astonishing what he was finding.  The more I learn about Parkinson's disease
the more I seem to find it a disease with a wealth of ignored information.
The pharmacological expertise of Tony and other patients also stunned me.
 You have the advantage of empiricism, you are living this problem.  I also
learned there were patients selected by their support group to be the first
member to try this procedure.  If the results of the surgery were good,
others would then follow.  The aggressive character of the support groups was
a pleasant surprise.
 
Schorr: People with Parkinson's disease in support groups tend to care about
each other.  There is a real sense of community in support groups.  When a
member tries a new therapy, we all want that therapy to benefit the member
and we hope it will help each of us.  We know PD is different in each of us.
 I know Alan, Jon and I react differently to the same medication.  Both Jon
and Alan find Eldepryl benefits them.  For me, Eldepryl makes me hallucinate.
 I was calling 911 repeatedly in the middle of the night while on an initial
trial of Eldepryl.  I had to discontinue its use.  PD is a complex disease.
 Support groups take some of the complexity away.  We find we are not alone.
 
Dr. Heit: I think PD is a cluster of diseases with known similarities.  The
differences are the unknowns.  Why does one patient have dyskinesia while anot
her is bothered by dystonia?  Support groups are indeed an important part of
living with this disease and understanding these differences.
 
Dr. Heit: While we are talking about support groups, we want to talk to
support groups about our program at Stanford, but more than that, we want to
learn from the experts -- those living with PD.  You have a lot to teach us.
 All the members of the Stanford team are interested in visiting support
groups.
 
Bonander: I just have one request from the patient community.  Please
remember we are awake during the operation.  Comments about not being able to
find the brain or that there seems to be no activity in the brain will be hear
d by the patient.
 
Dr. Heit: I do many procedures where the patient is awake.  This is not new
to neurosurgery.  Usually the biggest discussion in the OR is which CD to
play.  This is now the choice of the patient.
 
Bonander: Almost 3 hours have disappeared.  I want to thank you for taking
this time from your busy schedule to explain Stanford's pallidotomy program.
 We have learned much and I am sure the readers of this interview will learn
much.  We will be better decision-makers.  I would like to propose a deal
that sounds good to me.  I will cover the dinner tonight if you will cover a
pallidotomy for each of us, should we choose.
 
Dr. Heit: I think I have just been had!!
 
NOTE:  This was a most informative interview.  Leah, Jon and I learned much
about neurosurgery, MRI scans, psychological testing, and much more that time
and space limitations have forced us to omit.  Again, we would like to thank
Dr. Gary Heit for giving us this interview.  Support groups wishing to have
Dr. Heit or someone else from the Stanford program speak to them should
contact Melinda Fike at (415) 725-5280 or by fax at (415) 723-7813 for
details.
 
(1)  Mahlon De Long, Chairman, Dept of Neurology, Emory University, Atlanta,
GA
(2)  Lauri V. Laitinen, Neurosurgeon, Stockholm, Sweden(3)  Lars Leksell,
Neurosurgeon, Stockholm, Sweden
(4)  Robert Iacono, Neurosurgeon, Loma Linda Medical Center, Loma Linda, CA
(5)  Electrical stimulation is the passing of small electrical current at the
current probe location.  Depending on the size and frequency of current variou
s physical movements or visual images may result6 Lesion is destroying a mass
of brain tissue such that it blocks a neuron pathway.  The lesion is
performed by either heating the area (thermo lesion) or by cooling (cryosurger
y).
(7)  Internal capsule is a layer of nerve fibers on the outer side of the
thalamus and caudate nucleus.  These nerve fibers are important in normal
movement.
(8)  Hemiplegic refers to a unilateral paralysis.
(9)  Parkinson's Plus is the general name given to diseases that look
initially like PD, but later prove to be different.  Some of these are SDS,
PSP, MSA, et cetera.
(10) Tony Schoonenberg has Parkinson's disease and is a member of the
movement disorders team at Loma Linda Medical Center.
 
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Regards,
Alan Bonander ([log in to unmask])