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Dear Ivan: Please find a copy of an article written by Dr. Ron Alterman, the neurosurgeon who performs the Pallidotomy procedure at NYU Medical Center, it may help answer some of your questions. Also, I can arrange for you to speak with a gentleman from Maine who had the procedure in 1995. I wish you the best, Annie O'Sullivan Administrator NYU Center for the Study & Treatment of Movement Disorders P.S. The Learning Channel followed one of our patients during his "Pallidotomy" experience which is scheduled to air on March 16th. They met with him before his surgery, followed him into the hospital and operating room and interviewed him again a week after surgery. When I know the exact time, I will announce it to the list. Pallidotomy for Parkinson's Disease The NYU Center for the Study and Treatment of Movement Disorders Introduction Parkinson's disease (PD) is a neurologic disorder in which the nerve cells of the substantia nigra degenerate. These neurons are special for two reasons: 1- they are part of a brain system, the basal ganglia, which modulates movement and 2- they use the chemical dopamine to communicate with other neurons. The death of these dopaminergic neurons leads to an imbalance in the finely tuned basal ganlia system, resulting in a number of motor disturbances. Initially, this may be manifest as a mild tremor at rest, or stiffness in one extremity. With further degeneration, symptoms worsen and become debilitating. Stiffness, slowness of movement (bradykinesia), painful muscle cramps, and freezing (akinesia) may all result, making it difficult for the patient to perform such simple tasks as eating, walking, turning over in bed, or getting dressed. People's lives are destroyed. Family members watch helplessly as their loved one, once independent and vital, becomes increasingly dependent on others. Early on, PD responds well to medications. L-DOPA is the precursor molecule from which dopamine is formed. L-DOPA preparations such as Sinemet supplement the dopamine loss, ameliorating many Parkinsonian symptoms for many years. Pergolide and bromocriptine mimic dopamine's effects by stimulating the receptors in the brain to which dopamine normally binds. Eldepryl is believed to slow the process which leads to the death of the dopaminergic cells. These and other medications may be used alone, or in combination, depending on the patient's response, the preference of the treating physician, or other circumstances. L-DOPA therapy, however, is the mainstay of medical therapy for PD. In fact, a poor initial response to L-DOPA raises the possibility that the diagnosis of PD is incorrect. With time, the response to L-DOPA wanes. Patients respond to the medication less consistently and for shorter periods of time. They begin to suffer from medication side-effects, the so-called DOPA-induced dyskinesias (DID), and experience worsening "on-off" fluctuations. In the off state, these patients are rigid and immobile. They stare at the world with an expressionless "mask-like" face; many cannot stand without assistance from a walker or cane. In the on state they are freer and have less tremor, but severe dyskinesias neutralize the medication's positive effects. For many, the dyskinesias are worse than the PD, causing patients to limit the amount of medicine they take or to discontinue their medication entirely. In the latter stages of the disease, patients may have terrible gait imbalance and recurrent falls. They respond poorly to medication and are wheelchair bound. Dopaminergic neurons in the frontal lobes of the brain may also begin to degenerate causing a decline in cognitive abilities. What is Pallidotomy? Pallidotomy is a neuroablative procedure in which a small part of the globus pallidus, another part of the basal ganglia system, is destroyed. Animal models of PD have demonstrated that the loss of dopaminergic neurons causes the internal segment of globus pallidus (GPi) to become too active. This hyperactivity is believed to be responsible, in large part, for the stiffness and slowness experienced by Parkinson's patients, and may also contribute to tremor. By destroying part of GPi, the basal gangia system is "rebalanced" alleviating many parkinsonian symptoms. An unexplained benefit of pallidotomy is that DID is also relieved. Pallidotomy is not a new procedure. Neurosurgical pioneers including Irving Cooper at NYU, developed the operation in the 1950's and 60's. While their results were encouraging, the complication rates were quite high, and the procedure was abandoned in the late 1960's with the introduction of L-DOPA therapy. Over the last twenty-five years technological advances such as magnetic resonance imaging (MRI), microelectrode recording (MER), advanced stereotactic frames, and, of course, the computer revolution, have made it possible for neurosurgeons to refine the pallidotomy technique, yielding excellent therapeutic results and low complication rates. These advances, combined with the understanding that L-DOPA will not work forever, have led to renewed interest in pallidotomy. NYU has continued as a leader in this work. Indications for Pallidotomy Pallidotomy is not for everyone. The primary goal of our work at the Center for Movement Disorders has been to refine the indications for the procedure, thereby reducing complications and avoiding surgery for those who will not improve. Good candidates typically have had PD for 5-10 years during which time they have been responsive to L-DOPA. Their PD is asymmetric (ie. one side of their body is affected more than the other). They have a predominance of stiffness, slowness, and muscle cramping; tremor is not their primary problem. In the on state they suffer from DID. Younger patients tend to respond better than older patients; however, no one is eliminated from consideration based solely on their age. "Midline" symptoms do not usually respond well to pallidotomy. These include low voice volume, swallowing difficulty, unsteadiness, falls, and freezing. Resting tremor improves in some patients, but this is not the best indication for the operation. Keep in mind that the above descriptions of good and poor indications are presented for the sake of comparison. Most individuals suffer from a combination of symptoms some of which will improve with pallidotomy. A detailed discussion between the patient and surgeon is critical so that the surgeon understands which symptoms are most bothersome to the patient and the patient understands just what the operation will and will not do. Only then can an informed decision be made. This decision, of course, is made in light of our clinical evaluation, the neuropsychological testing, and positron emission tomographic (PET) results. The Preoperative Workup Patients who are interested in undergoing pallidotomy at NYU must be evaluated by Dr. Enrico Fazzini, our Parkinson's neurologist, and Dr. Ron Alterman, our neurosurgeon. A recent MRI of the head must be available to rule out significant brain atrophy or other brain lesions. Such findings may eliminate a patient from consideration. If Drs. Fazzini and Alterman agree that the patient is potentially a good candidate for pallidotomy, arrangements are made for preoperative neuropsychological testing and a PET scan. Neuropsychological testing is performed by Dr. Ken Perrine or one of his associates at the Hospital for Joint Diseases. The tests typically take 2-3 hours to complete. These are performed in order to rule out subtle memory loss, an early sign of the dementia which may accompany PD. We have found that individuals with even subtle cognitive deficits are at increased risk for having more severe cognitive difficulties following pallidotomy. If these early changes are discovered, we will not proceed with surgery. The final hurdle is the PET scan. NYU is the only center in the world which employs PET scan results in its clinical decision making. In true PD, PET scanning reveals the hyperactivity in GPi which I discussed in the indtroduction. We have demonstrated that patients without this hyperactivity will not respond to pallidotomy and should not be operated. Most important, if the PET scan reveals too little activity in the region of GPi, the patient may have one of the so-called "Parkinson's Plus" syndromes, rarer disorders which resemble PD but involve more than the dopaminergic system. "Parkinson's Plus" syndromes do not improve with pallidotomy in our experience. Once a patient is deemed a good candidate for the surgery, they are sent for medical clearance and presurgical testing. Assuming the patient has no medical problems which make surgery unsafe, we proceed with the pallidotomy. The Surgery Pallidotomy patients are admitted 2 days prior to surgery so that we may complete the preoperative motor evaluation. On the day prior to surgery, a full evaluation is performed with the patient off and on medications. This evaluation includes the performance of timed motor tasks and stableometry, a machine which assesses the patients stability and motor responsiveness. The pallidotomy must be performed with the patient off medications for at least 12 hours so that on the evening prior to surgery, Parkinson's medications are again stopped. The operation is usually performed in the morning so that the time off medications is minimized. All told, the operation takes 4-5 hours to perform, but there are only 2-3 hours of actual operating time. The first step is to apply the stereotactic frame, a simple procedure which takes 5 minutes to perform. This frame is rigidly fixed to the skull at 4 points. Each site is anesthetized. The frame is necessary to achieve the millimeter accuracy we require to perform pallidotomy safely. An MRI is then obtained with the frame and the images are transferred to our computer planning system. The operation is planned on the computer and the initial coordinates for the target are selected. The scalp is then shaved where the operation is to be performed, and the operation is begun. Accuracy is everything; therefore the patient's head is fixed in position for the operation. Every effort is made to make the patient as comfortable as possible. This includes placement of an air pillow behind the neck, pillows below the knees, and a nurse who will massage any cramps the patient experiences. For those who urinate frequently, a catheter is placed in the bladder to drain urine during the operation. It is promptly removed after surgery. The operation is performed through a 1/4 inch incision and a tiny hole that is drilled through the skull. The microelectrode is then inserted into the brain. Each recording session takes 20-30 minutes to complete. Typically only one or two trajectories are required, but sometimes 3 or 4 passes are needed in order to assure proper placement of the lesion. During microelectrode recording, the patient must remain perfectly still and quiet. This tends to be the most difficult part of the operation for most patients and every effort is made to keep them comfortable during this time. When recording has revealed our desired trajectory and target point, the microelectrode is replaced by our lesioning electrode and test stimulation is performed. The brain is stimulated with very low voltages to determine our proximity to critical structures which we want to preserve. These structures are the internal capsule and the optic tract. Damage to the former can cause paralysis while injury to the latter can cause partial blindness. The patient's cooperation during this phase of the operation is critical to the safety of the procedure. Our final safety check is to make a "test lesion". This is performed by warming the electrode so that the surrounding tissue is "stunned" but not destroyed. The patient is then examined, looking for any new signs of weakness. Once all of the safety checks are complete, the lesions are made. Typically, 4-5 lesions are made at 2 mm intervals along the lesioning trajectory. Each lesion takes 1 minute to perform. After lesioning, the electrode is removed and the incision closed with a single suture. The stereotactic frame is removed and a head wrap applied. The patient is then taken to CT scan to rule out a hemorrhage. Assuming no hemorrhage occured, the patient is taken to ICU where he or she will spend the night. In most cases, the patient is in ICU by lunch time. They may eat immediately and their Parkinson's medications are resumed. Post-operative Care Patients are observed in the ICU overnight for the sake of precaution. In most instances, the patient can be discharged home the next day or the day after. Patients return to NYU one week post-op for suture removal and a post-operative MRI which demonstrates the exact location of the lesion. Patients are usually followed by Dr. Fazzini every three months for the first year. During this time adjustments may be made in the medications depending on the patient's changing physiology. At the anniversary of the operation each year, we ask patients to return for a day of testing with Dr. Sterio. What can you expect? The response to pallidotomy is dependent on the patient's symptoms. A relief from stiffness is often noted on the operating table while the lesions are being made. Dyskinesias secondary to the medication are almost universally eliminated, something which the patient notices after taking 1 or 2 doses in the ICU. Family members may note more facial expression. There is often an emotional let down in the first week after surgery. In hospital, patient's often feel euphoric due to their new found freedoms and their delight at having survived. Once the newness of it all has worn off, there can be a slight let down which is often mistaken for a return of symptoms. It is important to keep in mind that there are dramatic physiologic changes occuring in the patient's brain which take 3-4 months to complete. During this time, as is always the case with PD, some days will be better than others. Try to keep a long-range perspective and not get discouraged by 1 or 2 "bad days". It is our experience that the full effects of the pallidotomy cannot be assessed until 6 months post-operatively. Concluding Remarks Thanks to many technological advances, modern pallidotomy is much safer and accurate than the procedure which was performed 35 years ago. Pallidotomy's continuing success has provided an invaluable therapeutic option for many PD patients whose response to medications is waning. The keys to a successful pallidotomy are careful patient selection and attention to details while performing the surgery. We believe that the excellent results and low complication rates achieved by the NYU Center for the Study and Treatment of Movement Disorders speak for themselves. Our physicians are available for consultation by appointment. We can be reached by phone at 212-263-1483.