Parkinson's Disease

Movement Disorders Treatment: Neurosurgical Medical Clinic Program

Over the past few years, we have developed a movement disorder program at Scripps Memorial Hospital in La Jolla. This campus is uniquely equipped to treat individuals with Parkinson's disease and other movement disorders, such as essential (familial) tremor. One advantage is the presence of the Gamma Knife on site for selected radiosurgical treatment. The majority of patients are treated with deep brain stimulator placement in our operating rooms which are well-equipped for computer assisted stereotactic surgery.

Parkinson's DiseaseRecent developments in imaging and computer technology have resulted in dramatically new and effective surgical treatments for Parkinson's disease (PD) and other movement disorders. PD is a progressive brain disorder characterized by tremor, muscular rigidity, and slowness of movement (bradykinesia). Effective surgical treatment evolved in the late 1940s and 1950s to provide relief from these disabling symptoms. Using stereotactic guidance technology, surgeons defined portions of the deep brain: the basal ganglia in which destructive lesions effectively reduced tremor and rigidity.

The introduction of L-dopa in the 1960s brought a marked reduction in stereotactic surgery for PD. L-dopa alleviates bradykinesia, rigidity, and tremor, allowing patients to improve in activities of daily living. Its combination with carbidopa (as Sinemet) reduces severe side effects and revolutionized the medical treatment of PD. Unfortunately, after many years of use, higher doses of Sinemet are required. Many patients develop jerking and writhing movements (dyskinesias) and rapid, unpredictable fluctuations in symptoms (on-off phenomenon) as well as other side effects. The short amount of time Sinemet lasts after oral dosage and interference with its absorption from the stomach by food protein, further complicated its use.

As these pitfalls in the medical management of PD were becoming recognized, important advances in stereotactic surgery were also occurring. The invention of CT and MR brain imaging allowed direct visualization of internal brain anatomy. Powerful and inexpensive computers improved stereotactic technique. Animal models of Parkinson's disease, based on a neurotoxin, MPTP, provided a better understanding of the neurophysiology of PD. There was a rediscovery of the globus pallidus as an effective target to relieve rigidity, bradykinesia, tremor and the dyskinesias of L-dopa use. Finally, a new target, the subthalamic nucleus, has finally emerged as the most effective target for deep brain stimulation to lessen the symptoms of PD.

Other tremors also respond to deep brain stimulation. These include essential tremor, post traumatic tremor and tremor resulting form multiple sclerosis. Dystonias also respond to DBS.

Indications for Surgery:

  • Idiopathic Parkinson's disease disabled by at least two of three cardinal signs: tremor; rigidity; bradykinesia/akinesia
  • Good response to L-dopa: a predictor of surgical success
  • Mild to moderate disease; intractable and disabling motor fluctuations: dyskinesias; severe "off" periods; freezing spells
  • Unsatisfactory response to optimal medical management
  • Absence of dementia or other medical conditions
  • Essential (familial) tremor, or tremor from multiple sclerosis or trauma
  • Dystonia and other movement disorders

Types of Surgery:

There are three commonly used surgical techniques:

  • Ablative techniques are surgical procedures which destroy a small target within the brain by destroying the tissue with an electrode. The electrode is advanced into the target and the target tissue is coagulated with heat from the electrode tip using an electrical current.
  • Deep brain stimulation has several advantages over ablative lesions. Although the procedure is also minimally invasive, no brain tissue is destroyed and the effect of the procedure can be varied during the post-operative period by varying stimulation parameters by externally programming the stimulator. Additionally bilateral destructive lesions in the right and left thalamus for tremor are contraindicated by severe side effects. Bilateral stimulating electrodes can be placed in the thalamus with minimal side effects.
  • Gamma Knife ablative lesions can also be created non-invasively using radiosurgery with the Gamma Knife in a few, selected patients.

Surgical Targets:

  • Thalamus: tremor
  • Globus pallidus: rigidity, bradykinesia, dyskinesia, dystonia
  • Subthalamic Nucleus: rigidity, bradykinesia, dyskinesia, tremor, postural instability

Deep Brain Stimulation

Deep brain stimulation (DBS) in the subthalamic nucleus may improve all of the cardinal symptoms of PD: tremor, rigidity and bradykinesia. Also dyskinesia may improve from stimulation and from the reduction of Sinemet which often follows DBS surgery. Some patients can stop taking Sinemet altogether. The effect of DBS is long lasting and dramatic in many individuals. On-off fluctuations, freezing and gait instability also respond to DBS.

Parkinson's DiseaseYears ago, surgeons noted that high-frequency stimulation deep within the brain (in the thalamus) temporarily stopped tremor during the period of stimulation. Neurosurgeons used this stimulation technique to refine the position of the electrode in the ventrolateral thalamus (VIM) prior to making a permanent ablative lesionto treat tremor.. A decade ago Benebid and others began placing stimulation electrodes into brain targets and connecting these to implantable stimulators (similar to heart pacemakers) to relieve symptoms of PD and other movement disorders. Continuous stimulation probably blocks the overactive subthalamic nucleus and lessenes the symptoms of Parkinson's disease.

The current technique of DBS involves the placement of a stereotactic frame on the morning of surgery, using sedation and local anesthesia. The brain is imaged by MR and CT scan. Sophisticated computer software is used to establish the exact position of the target in relationship to the frame. Next, a small perforation is made in the skull using local anesthesia, and a stereotactic guidance system is affixed to the head frame. Once the system is adjusted to the coordinates of the target, the surgeon can safely and accurately advance the electrode to the target. Microelectrode recording and stimulation help to determine the accuracy of electrode placement. Finally the electrode is connected to the stimulator which is implanted beneath the skin in the upper chest.

We implant the electrodes into both sides of the brain and place the stimulator during one morning of surgery. Therefore, the patient makes only one visit to the hospital for the entire process.

After days to weeks, the stimulator is programmed to optimal effect using a small computer which communicates with the implanted stimulator by an external antenna. Usually several hours or programming are required, requiring close cooperation of the neurologist or neurophysiologist, the patient, and the family.

We have an active program of movement disorder surgery at Scripps Memorial Hospital with the active cooperation of several neurologists who are experienced in treating movement disorders and programming the stimulators. We have treated more than 130 patients so far and invite your inquiries.

Also visit the Medtronic home page for further information.

Gamma Knife Radiosurgery

Parkinson's DiseaseProfessor Lars Leksell developed Gamma Knife radiosurgery 40 years ago to treat functional brain diseases, such a pain conditions and movement disorders. Just as modern imaging techniques have revolutionized stereotactic surgery, they have also led to the increasing use of radiosurgery in the treatment of brain tumors and vascular malformations of the brain.

The Gamma Knife has value in treating selected patients with tremor by making a destructive lesion in the thalamus in a non-invasive manner. These patients have tremor on one side only or will require a deep brain stimulator in the opposite thalamus with tremor on both sides of the body.