Parkinson's Surgical Procedure Shows Lasting Benefits, According to
A new method
of performing a surgical procedure in Parkinson's disease (PD) patients
is providing long-lasting symptom relief for those with moderate to
advanced stages of the disease, according to the results of an international
pilot study. Researchers in Cuba, in collaboration with an international
team of investigators from Emory University and other centers in the
U.S. and Spain, presented their findings on Oct. 14 at the American
Neurological Association's (ANA) 127th Annual Meeting in New York City.
"Brain surgery is not a new
concept in treating Parkinson's patients," says Jorge Juncos, M.D.,
associate professor of neurology, Emory University School of Medicine
and co-investigator of this study. "However, Cuban neurologists, neurophysiologists
and neurosurgeons are taking one of these surgeries, which they've been
performing since the mid-90s, to a new level and the results continue
to be promising."
Parkinson's disease is a
progressive disorder of the central nervous system affecting over one
million people in the United States. Symptoms include tremor, slowness
of movement and stiffness of muscles. The loss of nerve cells in an
area of the brain called the substantia nigra creates an imbalance that
disrupts normal movement. Although certain medications, such as levodopa
or L-dopa, can reduce the symptoms, they do not slow the progressive
deterioration in function of PD.
The surgical procedure used
in this study involves going deep into the brain, to a region called
the subthalamic nucleus, to destroy small clusters of nerve cells that
contribute to the above motor symptoms. The subthalamic nucleus helps
control movement on the opposite side of the body. Past research has
shown that by removing (i.e. "lesioning") or disabling (i.e. electrically
"jamming") this and other select areas in the brain improves motor function
in patients with PD.
Three years ago at an ANA
meeting, Cuban neuroscientists Lazaro Alvarez, M.D. and Raul Macias,
M.D., presented material showing they could safely lesion the subthalamic
nucleus on one side of the brain, called unilateral subthalamotomy,
that could later be followed by a second procedure on the opposite side.
Now these investigators have taken the procedure a step further by lesioning
the subthlamic nuclei on both sides of the brain simultaneously, a so-called
bilateral subthalamotomy. By reducing the number of surgical sessions
from two to one, the doctors reasoned they could reduce patient discomfort
and inconvenience, and perhaps lower the risk of the intervention itself.
In this pilot study, bilateral
subthalamotomy was performed on 18 Parkinson's patients at the Centro
Internacional de Restauracion Neurologica (CIREN) in Havana, Cuba. The
participants were followed for 24 months after surgery. Dr. Juncos and
Mahlon DeLong, M.D., professor and chair of Emory's Neurology Department,
both traveled to Cuba on several occasions to evaluate the participants.
"Following surgery, we examined
the participants in Cuba and evaluated their motor skills, stiffness
and tremor while off their PD medications," says Dr.. Juncos. "We also
reviewed videotapes obtained before and after the surgery, as well as
brain imaging studies."
Two years after their surgery,
as a group, patients exhibited approximately a 50 percent improvement
in motor symptoms and in drug-induced abnormal movements, compared to
their scores before surgery. Patients also exhibited significant improvement
in activities of daily living. Patients who also exhibited defects in
mental ("frontal") information processing before surgery showed improvement
in these defects after surgery. Although there were no serious permanent
side effects from the surgery, three patients with large lesions developed
severe abnormal involuntary movement (dyskinesias), imbalance and trouble
speaking. These symptoms improved gradually over the next 3-6 months
and the patients retained otherwise significant improvement in PD motor
Another benefit of this surgery
was an apparent 70 percent reduction in the doses of medication required
to treat the patients' motor symptoms. The smaller doses of medications
undoubtedly added to the benefits obtained from the surgery.
Dr. Juncos, speaking for
the team, says, "the outcome of bilateral subthalamotomy is showing
positive signs, both in sustained movement benefits and in the absence
of cognitive, speech or balance side effects. These problems were known
complications of previous attempts at using bilateral brain lesions
that targeted other areas of the brain like the thalamus and globus
pallidus. We are encouraged by the long-term efficacy and safety of
this new approach after two years of follow-up." Dr. Juncos presented
the findings of this recent study at the ANA on behalf of the Cuban
neurosurgeons and other investigators. The Cuban doctors were not able
to attend the conference because of recent hurricane damage to their
island and difficulties obtaining U.S. visas.
"This collaboration has been
and continues to be a great experience for researchers and patients
alike," Dr. Juncos explains. "The Cuban doctors have given their international
collaborators unfettered access to their patients, to imaging studies
and all other clinical material. The data have been the subject of open
scrutiny and authors outside of Cuba who have helped analyze much of
it. We, at Emory, feel very fortunate to have been a part of this study
and plan on expanding our relations in future studies with these researchers."
With these new results, researchers
will now need to explore how bilateral subthalamotomy compares to deep-brain
stimulation (DBS) of the subthalamus, a "pacemaker-like" approach recently
approved by the U.S. Food and Drug Administration for the treatment
of advanced PD. Because DBS required the use of two pacemakers (one
for each side of the brain) and connecting wires, it is more costly
than the lesioning procedures used in Cuba. Additional costs stem from
the need to periodically adjust the settings of the pacemaker devices
that drive the stimulators.
"Assuming the safety and
efficacy of these lesions performed in Cuba prove to be comparable to
that of the better established DBS technique, future investigations
will need to evaluate the benefits in relation to the costs of these
procedures," says Dr. Juncos.