fROM: WE MOVE News (http://www.imakenews.com/wemovenews/e_article000489397.cfm?x=b698y9t,b23F7l0n)
November 17, 2005
Avoidable Causes of DBS Failure
Why is this study important?
In 1997, the Food and Drug Administration approved the use of deep brain stimulation (DBS) for the treatment of Parkinson's disease and essential tremor and, in 2003, also approved the use of DBS for the treatment of dystonia. (Click here for more information on DBS.) Since that time, thousands of people have had operations for the placement of DBS electrodes and stimulators. At first, most patients were treated at centers that specialize in the treatment of movement disorders. However, as more surgeons have learned how to implant the electrodes, and more neurologists have learned how to program them, the operations are now being performed at less-specialized centers. Currently, there are no consensus-approved guidelines for the
* Selection of patients who are most likely to benefit from this treatment
* Training of surgeons who implant the electrodes
* Training of personnel who program the stimulators
* How, when, and where the programming takes place
* How to educate patients and physicians about complications
* How the complications should be managed
What was the purpose of the study?
The researchers hoped to be able to improve the treatment of dystonia, PD, and ET with DBS by studying a series of patients who had less than favorable results after their operations for placement of DBS leads and stimulators. "Favorable" was defined as being able to decrease the amount of medication that was required before the DBS operation and maintain the same level of functioning.
Who participated in the study?
Over a two-year period, 41 patients who had had their operations elsewhere were evaluated at one of two movement disorder centers: the University of Florida or Beth Israel Medical Center in New York. All of the patients were having problems with DBS treatment for PD, ET, or dystonia. Neurologists and neurosurgeons who specialize in the treatment of movement disorders at both of these institutions examined the patients, their medical records, and the DBS leads and stimulators.
What were the results of the study?
The most important factor in predicting outcome of treatment with DBS is proper patient selection. In 32 of the 41 patients, the specialists agreed with the diagnosis that had been made before the operation. In nine patients, the diagnosis was changed. In five patients, a condition was diagnosed that would not have been expected to benefit from DBS.
Thirty patients had seen a movement disorders specialist before the operation. Fourteen patients had neuropsychological testing before the operation. Five patients did not take the correct medicine for a long enough period of time before the operation to determine whether or not the medicine was effective. Five patients were also found to have had severe problems with thinking clearly (cognitive impairment) before the operation.
Nineteen of the 41 patients had the DBS leads in the wrong place. When the surgeons at the University of Florida or at Beth Israel Medical Center replaced the leads, seven of the patients had marked improvement and three others had partial improvement (defined as symptom improvement but not to the level expected by the researchers). Three patients had problems with the batteries in the neurostimulator, two had infections, and one had a broken lead.
Seven patients had no access to programming for their stimulators-two because they moved and two because their doctors moved. Eight more patients had had their operations at centers far from their homes, and they had trouble finding a device programmer who was near them. In 15 patients, programming appeared to be inadequate. The specialists were able to reprogram 51% of these leads, but the sessions took almost twice as long as normal. Thirty patients required one or more medication changes.
After being treated by movement disorders specialists at these two centers, 21 of the 41 patients in whom DBS had been previously determined to have "failed" had good outcomes. In addition, another six patients had modest improvement.
What was the authors' conclusion?
"This study highlights the important point that all of these complications were potentially preventable. As more DBS is performed, practitioners will need to be aware of the timeline of preventable problems, which may include failures of triage, screening, surgery, and postoperative follow-up. . . This case series provides important insight into the common reasons for 'DBS failures' and proposes some effective strategies for their management."
Okun M, Tagliati M, Pourar M, et al. Management of referred deep brain stimulation failures. A retrospective analysis from 2 movement disorders centers. Arch Neurol 2005;62:1-6.
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