[log in to unmask] writes:
> Bonnie, thank you for the insightful article that you posted to the
Internet. I'm very surprised that there has not been more discussion on
it...Do you have any further information on it?
--
I found this in my files...
RSNA MEETING: Noninvasive Gamma Knife May Replace Surgery For Many
Patients With Parkinson's
CHICAGO, IL -- December 3, 1997 -- A noninvasive radiosurgical technique
may ultimately replace surgery for many patients with Parkinson's
disease and other movement disorders whose symptoms cannot be controlled
by medicine, according to results of a preliminary study presented today
during the 83rd Scientific Assembly and Annual Meeting of the
Radiological Society of North America (RSNA).
"Stereotactic radiosurgery shows promise as an alternative to surgery
to relieve the uncontrolled movements that are characteristic of
Parkinson's disease and other movement disorders," said David Friedman,
M.D. of Philadelphia's Thomas Jefferson University Hospital.
The technique is performed with equipment called a gamma knife that
uses magnetic resonance (MR) imaging to identify the radiosurgical
target. The radiation destroys selected portions of the globus pallidus
or the thalamus, structures deep within the brain that are responsible
for the tremors and other involuntary movements that are characteristic
of Parkinson's disease.
The surgical treatment for Parkinson's disease is to make a small hole
in the skull and place a probe into the brain which heats and destroys
the targeted tissue, according to Howard W. Goldman, M.D., Ph.D.,
professor and vice chair, department of neurosurgery.
"Our study looked at the success with the gamma knife in patients who
were too old or ill to undergo surgery," Dr. Goldman said. "We've had
such success, we're now offering it as an alternative to other patients
as well."
According to Dr. Goldman, as many as 50,000 patients in the United
States could benefit from the technique each year. "Nearly everyone with
Parkinson's disease eventually becomes refractory to pharmaceutical
treatment or develops side effects to medication, usually after five to
eight years of treatment," he said.
In the study reported by Dr. Friedman, 12 patients were treated with
the gamma knife. Seven patients showed marked improvement in their
symptoms, three had moderate
improvement and two showed mild improvement with follow-up of three
months.
With radiosurgery, it takes approximately six to eight weeks to begin
to see the effect of the treatment, according to Dr. Friedman. The
results at three months were comparable to those achieved with surgery,
he said.
Thalamotomy -- destruction of tissue in the thalamus -- is used to
control tremors. Pallidotomy -- destruction of tissue in the globus
pallidus -- is used to control rigidity and larger involuntary
movements, Dr. Friedman said.
The advantages of radiosurgical thalamotomy or pallidotomy with the
gamma knife compared to conventional surgery, according to Dr. Friedman
and Dr. Goldman are:
-- It is a noninvasive procedure without the risks of hemorrhage or
infection that are associated with open surgery. "The only adverse
effect seen with the gamma knife was late-onset swelling of brain tissue
in two patients that largely resolved over time," Dr. Friedman said.
Swelling also can be a side effect of conventional surgery, Dr. Goldman
said.
-- Patients are hospitalized for only 24 hours compared to three or more
days with surgery.
-- There is little or no recovery time. Recovery from surgery takes
about two weeks. "The effects of the gamma knife occur gradually, so we
typically don't see side effects such as weakness and confusion that
sometimes occur immediately after surgery," Dr. Goldman said.
There are 90 gamma knife machines in use worldwide, 32 in the United
States.
--
PMID: 9204114, UI: 97348047
Acta Neurochir (Wien) 1997;139(5):442-445
Gamma knife pallidotomy: case report.
Bonnen JG, Iacono RP, Lulu B, Mohamed AS, Gonzalez A,
Schoonenberg T
We report a case of gamma knife pallidotomy resulting in a permanent
contralateral
homonymous hemianopsia and transient contralateral hemiparesis with some
improvement in contralateral parkinsonian symptoms. This case
illustrates the risk of gamma knife pallidotomy which precludes
physiologic target localization and can subject structures surrounding
the target to a significant radiosurgical dose. Until noninvasive
physiologic target localization is available gamma knife pallidotomy and
thalamotomy should be limited to patients with an unacceptably high risk
for stereotactic percutaneous thermocoagulation.
--
Judith Richards, London, Ontario, Canada
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