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Surgery for Parkinson's disease?

TORONTO, CANADA. It is estimated that more than one per cent of all Americans over 60 years of age suffer from Parkinson's disease (PD). There is no medical cure for the disease and some of the drugs used to treat its symptoms (levo- dopa) may ultimately speed its progression. This fact has rekindled the interest in using brain surgery to stop the disease or at least ameliorate its effects. Dr. Anthony Lang MD, a specialist in Parkinson's disease at the University of Toronto, has just published an excellent review of the current state-of-the-art surgery for PD. Dr. Lang warns that none of the surgical procedures used for PD today have been exposed to rigorous, double-blind, randomized clinical trials. Says Dr. Lang "As long as there are willing neurologists and surgeons and desperate patients, this problem will persist until the professional community decides to regulate the practice of its members or until external regulations are imposed." He lists the example of adrenal medullary transplantation which was quite popular for awhile, but which has now been abandoned as useless and dangerous.

Surgery for PD can involve incisions (lesions) made in various parts of the brain in an attempt to reduce tremors and other symptoms of the disease. Thalamotomy has now been used for 40 years. It is somewhat effective in reducing tremors, but can have serious side effects. Pallidotomy (surgery involving the globus pallidus region of the basal ganglia) was reintroduced in 1992, but is still the subject of great controversy; as a matter of fact, there is still no consensus as to where the incision should actually be made. Pallidotomy may help with dyskinesias (involuntary muscle movements) caused by leva-dopa, but its effects are short-lived (less than two years). Deep brain stimulation (DBS) involves the implantation of electrodes in the thalamus or globus pallidus areas of the brain. The electrodes are activated by an electronic device (similar to a pacemaker) installed in the chest cavity. Some preliminary results are promising, but again, there is no actual agreement as to where the electrodes should be placed and the only reasonably valid trial of this technique involved only 13 patients. Transplantation of human fetal tissue into the brains of PD patients is an emerging approach. This procedure requires the use of six to eight or more fetuses for each patient and, not surprisingly, is fraught with controversy. It may provide some benefits in patients younger than 60 years (none in patients older than 60 years) and can have serious side effects. Dr. Lang concludes his review with the observation that "Despite numerous claims, the evidence for benefit from surgical therapies in patients with PD is relatively weak." NOTE: This study was partly funded by Medtronic, Inc., a manufacturer of DBS equipment. [75 references]
Lang, Anthony E. Surgery for Parkinson disease: a critical evaluation of the state of the art. Archives of Neurology, Vol. 57, August 2000, pp. 1118- 25

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