Innovative Neurosurgery
Offers Treatment for Movement Disorders
May / June 2004
The Center for Functional and Restorative Neurosurgery provides
innovative surgical treatment for patients with movement disorders
such as Parkinson’s Disease, essential multiple sclerosis
tremor, dystonia and medically intractable epilepsy. Created
by the Penn Neurological Institute, the Center will serve
as a functional surgery center for the treatment of neurological
disease and, ultimately become an international training
center
for surgeons in the functional neurosurgery field. Currently,
the main focus of the Center for Functional and Restorative
Neurosurgery is deep brain stimulation however, vagal nerve
stimulation and virtual surgeries are also being performed
to further expand treatment and research in the field.
Deep Brain Stimulation
Two years ago, the FDA-approved Deep Brain Stimulation (DBS)
of the subthalamic nucleus (STN) for the treatment of Parkinson’s
Disease and tremor. Since its inception, DBS has proven to
be extremely successful. “We now have patients who are five
or six years post surgery and doing very well,” says Gordon
Baltuch, MD, PhD, assistant professor and director of
the Center for Functional and Restorative Neurosurgery and
one of only a few physicians in the world to perform DBS.
Already proven successful in Parkinson’s Disease and tremor,
DBS is now utilized for general dystonia, cervical dystonia
and epilepsy. General dystonia is a progressive condition
in which patients have abnormal body movements. Cervical dystonia
(also known as spasmodic torticollis) in its most severe form
prevents patients from moving their necks from side to the
midline despite all therapies, including medication and injections.
Recently, both general and cervical dystonia have been successfully
treated with DBS.
DBS is based on the principle that electronic stimulation
of particular regions of the brain can ameliorate the major
symptoms of some movement disorders. The procedure involves
guiding electrodes deep inside the brain to the tiny STN,
a structure only about 6 mm to 8 mm in size. Electrophysiologic
mapping, completed in the operating room under stereotactic
guidance, provides more precise localization. When the electrode
is in place, the STN is stimulated and the surgical team observes
the effect on the patient, who is awake during the operation.
A second electrode is placed on the right side of the brain
and a battery-powered pacemaker-like device is implanted under
the right collarbone now stimulating both sides of the brain.
“Up until this point the stimulators have been blind, meaning
they just stimulated without detecting anything in the brain.
In conjunction with the Penn
Epilepsy Center, we will be
starting
a DBS clinical trial for epilepsy that utilizes a ‘smart stimulator’
which has the ability to detect when a seizure is going to
happen and then stimulate in response to it,” explains Dr.
Baltuch.
Although DBS is still a niche surgery and reserved for patients
with advanced disease, the indications are broadening. According
to Dr. Baltuch, DBS should be considered earlier in selected
patients with advanced Parkinson’sDisease. To date, more
than 250 DBS procedures have been performed at Penn, which
makes
it the largest treatment center in the United States.
Vagal Nerve Stimulation and Other Therapies
In vagal nerve stimulation, neurosurgeons place a wire in
the vagal nerve in the neck and send electrical signals that
stimulate the cranial nerve. Already proven to combat seizures
in epilepsy, vagal nerve stimulation may help depression as
well. “We are hoping to obtain FDA approval for vagal nerve
stimulation for depression within the next year,” says Dr.
Baltuch.
Other future procedures (which are currently in clinical
trials for Parkinson’s Disease) may include delivering a growth
factor into the brain through a catheter or putting an engineered
cell directly into the brain. “We want to gear the Center
towards what we call the new neurosurgery, which is minimalist
in terms of its invasiveness into the brain and treats conditions
that classically have not been treated by neurosurgeons, such
as ALS or Lou Gherig’s disease, Alzheimer’s, obesity, obsessive-compulsive
disorder and substance abuse,” explains Dr. Baltuch. “These
procedures do not ablate the brain and are completely reversible.
Their application is not too far off in the future. In fact,
substance abuse has been successfully treated with stimulation
in Asia.”
Virtual Surgery Clinical Trial
Along with Penn neuroradiology, Penn neurosurgeons are participating
in a clinical trial that is testing a new prototype of
a system
that conducts neurosurgery in virtual reality. “This is exciting
technology that should improve surgical outcomes. Similar
to a pilot simulator, surgeons perform the operation and face
potential problems in virtual reality—before operating on
the patient in real life,” says Dr. Baltuch. Penn is one
of just a few centers worldwide participating in this trial.
These new neurosurgical procedures carry a concern of the
ethics of performing procedures that affect brain activity.
Specialists at the Center for Functional and Restorative
Neurosurgery are aware of these concerns and have partnered
with Penn Bioethics
to discuss the societal implications of these applications.
|
