Burning a tiny hole deep in the brain can relieve some symptoms of Parkinson's disease for more than five years, though certain major improvements wear off, researchers reported today.
The surgery is called pallidotomy and involves the removal of a part of the brain that controls movement. It can be useful when medicine alone cannot control the progressive neurological disorder, doctors in Toronto concluded in their study published today in the New England Journal of Medicine.
The surgery is different from that undergone by actor Michael J. Fox, the Parkinson's patient who left television last month to focus on finding a cure. Fox had a thalamotomy, a decades-old operation that destroys overactive, tremor-causing nerve cells by burning or freezing a pea-size spot in the brain.
The study is a follow-up to one published in 1997 about the first 40 patients the doctors treated with pallidotomy.
Doctors knew that, over the short term, pallidotomy can relieve symptoms such as tremors and stiffness, as well as uncontrollable arm and leg movements caused by the medicines used to treat Parkinson's disease.
The earlier study of 40 patients found significant improvement both while taking medications and off them.
The follow-up found that the reduction in tremors and rigidity while off medication was nearly as marked 4 1/2 years afterward as at the first checkup six months after the operation. So was the reduction in the twitches and jerks caused by medicine.
But improvements in the level of daily functioning did not last. The study did not give details, except as composite scores in several scales designed for Parkinson's patients.
In addition, only 20 of the patients could be included in the follow-up, and they were generally the ones who had responded best at the start, wrote Dr. Jennifer Fine, a neurosurgeon at Toronto Western Hospital.
``This bias may limit the general applicability of our results,'' Fine wrote.
On the Net:
Unified Parkinson's Disease Rating Scale: http://www.wemove.org/parâ€”rs.html
NIH agenda for Parkinson's research: http://www.ninds.nih.gov/whatsnew/pdagenda2000/nihparkinsonsagenda.htm