Thursday, August 31, 2006
Brain surgery might make the ordeal of Parkinson's disease a little easier for some patients, according to a study published in this week's issue of the New England Journal of Medicine.
While several medications can help control the symptoms of this degenerative disease, they can produce side effects, including uncontrollable body movements that can be almost as disturbing as the shaking and tremors of the disease itself.
...."For patients and their families, this is a landmark study because it focuses on what is really important to them: quality of life. And it shows, very clearly, that DBS improves quality of life," said Dr. Jaimie Henderson, director of stereotactic and functional neurosurgery at Stanford University Medical Center.
...Most doctors already know that deep-brain stimulation helps Parkinson's patients, but this study is the first to prove that the surgery brings greater overall benefits. [Most doctors know this? On what is this assertion based? The interviews with the neurosurgeons?-ed]
...."Hopefully, this study will provide enough evidence to convince these physicians of what functional neurosurgeons have known for years: DBS is the best treatment for Parkinson's disease when medicine begins to fail," Henderson said.
At the very, very end we learn that there are potential complications - like dying - from the surgery. And the reporter did interview one lone dissenting voice:
One doctor voiced concern about the enthusiasm this study might generate. "It is important to stress that DBS is not a cure," said Dr. William J. Weiner, director of the Maryland Parkinson's Disease and Movement Disorders Center.
He said the study also does not help doctors understand if the surgery is best for patients early in their diagnosis, or for those with more advanced cases of the disease.
"This study will not help us decide this issue, and there may be an over reaction to the results of the study," Weiner said. "It may also push patients and neurologists into performing DBS before it is required."
ABC news doesn't tell us if Dr. Jaime Henderson has any financial ties to Medtronic, the maker of the electronic stimulator, but Reuters points out that 21 of the 38 authors of the study do.
The study did show some improvement in the stimulated patients. It measuered outcomes in several ways - through some standardized Parkinson symptom evaluation questionairre's and through patient diaries. I'm not familiar enough with the symptom evaluation questionairre's to know if the differences are signficiant or not, but it appears from the data that everyone - the medicated and the stimulated - started out in the middle-range and stayed there, though there was more improvement in the scores at six months among the stimulated. (It should also be noted that the medicated group was slightly weighted toward more severe illness from the beginning than the stimulated group.)
The diary information is easier to interpret. Both the stimulated and the medicated spent the same amount sleeping and in a state they described as "neither fully mobile nor fully immobile" at the beginning and the end of the study. The stimulated people went from a mean of having six hours of being immobilized by their disease to only two hours a day of immobility, while the medicated people remained steady at five hours. The stimulated group also went from three hours a day without troublesome tremors to seven hours a day. That is a dramatic improvement. It means having a full day of almost normal activity.
But it comes at a price:
Serious adverse events were more common with neurostimulation than with medication alone (13 percent vs. 4 percent, P<0.04) and included a fatal intracerebral hemorrhage. The overall frequency of adverse events was higher in the medication group (64 percent vs. 50 percent, P=0.08).
Other serious adverse events were infection at the site of the stimulator, worsening of mobility, and stimulator malfunction. They also included a death from pneumonia and suicide, but it's impossible to say that they had anything to do with the stimulator. And to be fair to the stimulator, the adverse events were few.
But any surgery comes with a risk, and we would do well to consider them carefully before going forward with routine brain stimulators for Parkinson's disease. Espeically for the frail elderly who are a long way from the 53-67 years old study subjects.
posted by Sydney on 8/31/2006 07:53:00 AM 0 comments