Welcome to the information site for the Indiana University Movement Disorder Surgery Program.
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Surgical treatment of some movement disorders can be of great benefit for certain types of patients. It has been available at select centers for the past seven or eight years. Movement disorders which have been shown to benefit significantly from operative intervention include Parkinson's disease (PD), essential tremor (ET), and some types of dystonia.

Movement disorder surgery is an example of stereotactic surgery. The word "stereotactic" means to touch (something) in three dimensional space. When applied to surgery it refers to operations which are performed using guided probes passed through "silent" areas of the brain as opposed to procedures where the skull is opened and the surgeon directly manipulates the areas of interest. The probes are guided by a stereotactic frame (Figure 3) which attaches to the patient using four pins which anchor to the skull. An image (usually an MRI scan) of the head and brain with the frame in place is then obtained and fairly simple geometric techniques are used to plot a path (trajectory) passing from a dime-sized opening in the skull to the desired target in the brain.

Stereotactic surgery was introduced into neurosurgery in the late 1940's and it was applied to the treatment of PD very soon thereafter. It continued to be fairly widely utilized until the introduction of L-DOPA in 1968. Because of the optimism surrounding this medical management, the surgical treatment of movement disorders was virtually abandoned for the next twenty years. It gradually became apparent, however, that some patients, after being on medication for a number of years reached a point at which they no longer had adequate control of their symptoms. For this reason, interest again began to develop in the surgical treatment of these diseases. Beginning in about 1992, in Sweden, some of the prior operations were re-introduced, generally in modified form reflecting advancements in medical imaging and other improvements. At about the same time, surgeons at Emory University popularized the process of intra-operative physiologic monitoring which appeared to significantly improve the accuracy of the surgical targeting.

The Indiana University Movement Disorder Surgery (IUMDS) program began in 1995 doing procedures such as pallidotomy for PD, thalamotomy for ET and some deep brain stimulator (DBS) implantation for PD. Although these procedures produced excellent results, by November, 1999, convincing evidence had developed that DBS using the subthalamic nucleus (STN) as the target (Figure 1) offered significant advantages in most PD patients and we switched then to STN-DBS as the primary initial treatment modality for PD patients, and thalamic DBS for ET patients. More recently, we have obtained excellent results using DBS in the Globus Pallidus for treatment of dystonia. Pallidotomy and thalamotomy are still done in selected patients for certain indications.

The IUMDS program continues to be a cooperative effort between the Departments of Neurosurgery and Neurology. All patients are followed jointly by faculty physicians in both disciplines. Patients are generally referred for surgery after their neurologist has made the determination that they are refractory to medical management. This means that their symptoms are no longer consistently well-controlled by any combination of medication (please see About the Procedure for a more detailed discussion of this situation). This is a determination that can only be made by a neurologist familiar with all the medical options including newer drugs which may have been recently introduced. To insure consistency in this regard and because all stimulator programming is done in the IU Neurology Clinic, all patients have an initial evaluation by one of the IU movement disorder neurologists.

Once it has been determined that all appropriate medical treatment options have been exhausted, patients will be considered for movement disorder surgery. The various options are discussed between the patient, the movement disorder neurologist and the neurosurgeon and the procedure felt to be most likely beneficial for the individual patient is recommended. Once the patient decides to proceed, a surgical date is arranged and appropriate pre-operative studies are carried out.

Surgery scheduling is dependent upon the procedure. Intra-operative electrophysiologic monitoring is utilized for all movement disorder surgery at IUMC. This involves the participation of three members of the neurosurgical faculty (two neurosurgeons and a neurophysiologist) for each case. DBS implantation is typically done in two separate trips to the operating room. The electrode implantation is done on a Wednesday. On Thursday the patient has an MRI scan to confirm position of the electrodes and is then returned to the operating room on Friday for a short procedure under general anesthesia to implant the generators. The electrode implantation is a stereotactic procedure and is done under local anesthesia for the purpose of increasing patient safety and to allow intra-operative testing of electrode effectiveness. This portion of the operation often takes 7 - 8 hours. Thus the procedure is divided as above to minimize patient (and surgeon!) fatigue. Pallidotomies and thalamotomies are done on Wednesdays also, but an additional trip to the operating room is not required since there is no generator to implant.

Patients are typically discharged the day after the last surgical procedure, i.e. Saturday for DBS cases, or Thursday for pallidotomies or thalamotomies. The stimulators are not turned on until the patient returns for their first post-operative visit about a month after surgery. This is because the procedure of introducing the electrode into the brain produces a small amount of edema (swelling) around the electrode site. In fact, patients often note some temporary symptomatic improvement from this effect. If the stimulator were activated immediately after implantation while the edema was still present, the settings required for optimal effect would change continuously as the edema resolved over the ensuing 10 - 14 days. Therefore it is best to wait until the settings would be expected to remain stable for at least some period of time.

A number of the stimulation parameters such as stimulation rate, amplitude (strength), pulse width and the specific combination of the four contacts on the electrode are physician-modifiable. This is usually referred to as programming and is a crucial part of the process necessary to achieve optimal results. Although there are typical ranges within which patients will experience beneficial effects, the ideal setting is likely to be different for each individual patient. The initial programming session at which the stimulator is activated for the first time often requires several hours because the patient must be observed for a period of time after each modification is made. Concomitant with programming, the patient's medication must be adjusted to reflect the stimulator settings. Subsequent programming sessions are carried out at 2 to 4 week intervals until the optimal combination of stimulator settings and medication dosage for each individual patient is determined. Then patients still need to be checked periodically. Post-operative stimulator programming and the consequent change in medication schedules is a delicate and time-consuming procedure. Thus it is strongly recommended that patients return to the IUMDS clinic to have these services performed. However, we do appreciate the inconvenience of having to travel long distances for follow-up appointments. Furthermore, we are dependent upon the goodwill of our referring neurologists. Therefore every effort is made to return the patients to the care of their local neurologists as quickly and to as large an extent as possible. Patients themselves cannot modify these parameters settings but can turn the stimulator on and off. There is rarely any need to do so, however, and typically patients do not do anything to the stimulators in between programming sessions.

In properly selected patients, movement disorder surgery can produce remarkable results. Please review other sections of this website for a more detailed discussion of the selection process and the surgical procedures.