| Clinical Programs: | |
| Brachial Plexus | |
| Epilepsy Surgery | |
| General Neurosurgery | |
| Head Injuries | |
| Movement Disorder Surgery | |
| Neuroendoscopy | |
| Neuro-Oncology | |
| Neurovascular Surgery | |
| Pain | |
| Pediatric Neurosurgery | |
| Spinal Instrumentation | |
| Stereotactic Surgery |
Surgical Management of Movement Disorders
The Medical College of Georgia movement disorder program is a
multidisciplinary program staffed by a neurosurgeon, neurologist,
neuropsychologist, physician's assistant, nurse practitioner, and physical
therapy with specialization in the care and rehabilitation of patients with
movement disorders. The full spectrum of movement disorders is treated. The
neurosurgery team has over 20 years experience in the surgical management of
movement disorders.
Surgery is considered only after all attempts at conservative management
have failed or have provided suboptimal results. The type of surgery varies
depending upon the particular movement disorder. In general, significant
reduction of abnormal movement and/or tone can be expected in 80% of cases.
The incidence of significant postoperative complications is quite low.
The movement disorder staff works closely with referring physicians during
evaluation and treatment to maximize continuity of care, particularly in the
postoperative period.
In addition to surgery, selected patients with disorders involving localized
increased muscle tone (e.g., hemifacial spasm, laryngeal dystonia,
torticollis) may be treated with botulinum toxin (BoTox) injections.
Deep Brain Stimulation (DBS) and Parkinson's
Disease (PD)
...view
video
Currently, DBS is most commonly performed on drug-resistant Parkinson's
disease (PD). PD is a degenerative disease of the nervous system. It is due
to degeneration of nerve cells in a structure called the substantia nigra.
This structure is part of an interconnected system of groups of nerve cells
called the basal ganglia or basal nuclei. These structures form a part of
the motor system which controls tone and posture. When the substantia nigra
degenerates, there is a marked decrease in the neurotransmitter dopamine
which is essential for proper function of the basal ganglia. Initially, the
majority of PD cases respond well to L-DOPA (Sinement), the precursor of
dopamine. However, after 5 or more years of use, patients often respond less
consistently and for shorter periods of time. Side effects also begin to
begin to appear, most noteably "on-stage" dyskinesias. These are abnormal
involuntary movements which usually appear within an hour of the most recent
dose of L-DOPA and subside gradually until the next dosage.
DBS of the subthalamic nucleus (STN) is becoming the most commonly performed
operation for PD. It has recently been FDA approved. It is effective in
alleviating the rigidity, slowness of movement, on stage dyskinesias, and
tremor in about 80% of cases. It has also been effective in improving gait
and gait freezing, but this usually requires bilateral (i.e., right and
left) implants. It is more effective in younger and less disabled patients.
It is not effective in cases that have not shown a good response to L-DOPA.
In general, it improves signs and symptoms most that are present when a
patient is in the "off-state" (the wearing off state of L-DOPA, nearing the
time when the next dose is due). The exception to this is the "on-stage"
dyskinesias which also improve after STN DBS. DBS patients reduce their dose
of L-DOPA an average of 50%.
The surgery is performed under local anesthesia in order to allow testing of
the patient during surgery. However, many of the preliminary portions of the
operation, which do not require patient cooperation, are performed with
patient receiving a rapid-acting intravenous sedative and narcotic in order
to maximize comfort.
At
MCG, state- of- the- art imaging (MRI), computer workstation, and
microelectrode recording equipment is utilized. After sedation, a scalp
block is performed and a stereotaxic basering together with a localizer is
fixed to the patient's head. High resolution images of the target area are
obtained and transferred via ethernet to the computer workstation, which is
used to derive the target coordinates and pathway or trajectory for the
recording and stimulating electrodes and DBS electrode.
The patient is then taken to the operating room where the basering is fixed
to the operating table. The head is shaved, sterilized and draped. After
injecting local anesthetic, a transverse frontal incision is made and right
and left frontal bur holes (about 1/2 inch diameter) are made The aiming arc
is then placed on the basering and the microelectrode guide is attached to
it.
An
array of four microelectrodes is advanced to the right (and subsequently the
left) targets with continuous recording of electrical activity. Typically,
high frequency and amplitude electrical activity is recorded at the target
point and this activity is further amplified with passive movement of the
opposite arm. During the recording the patient is usually awake so that
recordings from the target site are optimized.
After completion of the recordings, the DBS electrode is introduced to the
target area. Proper positioning is confirmed with intraoperative fluoroscopy
.Stimulation is performed after the implant to assure that no unwanted motor
or speech responses are obtained. None of this is felt by the patient since
the brain is not pain-sensitive. The DBS electrode is then locked in place
with a silastic ring and ca, and fluoroscopy is repeated to assure proper
electrode position. After that the other side is implanted similarly. The
pictures below show postoperative MRIs with DBS electrodes in place.
After surgery, patients spend the first postoperative night in the ICU
(intensive care unit) for precautionary purposes. They then transfer to a
regular room, and usually are discharged home on the third postoperative
day.
The patient then returns within one to two weeks to have the two pulse
generators implanted as an outpatient procedure. Programming of the
stimulators will begin after that.
Patients often notice alleviation of rigidity and bradykinesia (and tremor
in cases with tremor) immediately after implantation, even before DBS is
begun. Successful implantation not uncommonly leads to transient increase in
dyskinesias in the immediate postoperative period. These will usually
respond to a decrease in L-DOPA dose.
Other Movement Disorders and Operations
Deep Brain Stimulation (DBS) is also used for essential or familial tremor .
This involves the permanent implantation of stimulating electrode (picture)
into a different area of the brain called the thalamus. The basic technique
is very similar to that of STN DBS. Patients with bilateral tremor will
require bilateral implantation, which is done in stages. Depending on the
patient's age and overall health the second operation is usually performed
three to six months after the first.
Pallidotomy for the most part has been replaced by STN DBS in PD. The
technique is similar to DBS except that a permanent lesion is made in a
different location instead of implanting a DBS electrode. Pallidotomy has
been used successfully for a condition referred to as dystonia which
involves increased tone and associated abnormal posturing of trunk and/or
limbs depending on the particular disorder. Depending on the etiology of the
dystonia, as many as 80% of patients have significant reduction in their
dystonia. Pictures 6a and 6b show a typical pallidotomy. Most recently, the
FDA has approved pallidal DBS for treatment of certain dystonias.
Thalamotomy
is rarely used since the introduction of DBS. Like pallidotomy, it is also a
destructive procedure that requires coagulating an approximately six
millimeter diameter area of the thalamus. It remains very effective in cases
of drug resistant intention tremor that occur as a result of severe head
trauma or multiple sclerosis.
Gamma knife
thalamotomy is a non-invasive technique that may be offered to patients with
disabling tremor who are not candidates for open thalamotomy or DBS.
Selective Rhizotomy with or without peripheral nerve or muscle sectioning is
used for medically refractory torticollis which is a cervical form of
dystonia that involves static or repetitive rhythmic turning of the head.
The Movement Disorder Surgery Team
Joseph R. Smith, M.D., F.A.C.S., Director of Functional & Stereotaxic
Neurosurgery
Kapil Sethi, M.D., Neurology, Chief, Section of Movement Disorders
John Morgan, M.D., P.h.D., Department of Neurology
Robbie Allen, Ph.D., Neurophysiologist, Southern Neurophysiology Associates
Caroline diDonato, Nurse Practitioner, Assistant Clinical Professor,
Movement Disorder Service
Gregory P. Lee, Ph.D. Neurology, Director of Neuropsychology Services
The program staff welcomes any inquiries or referrals and can be reached through MCG
Physicians Direct at 1-800-733-1828.