Article
Patterns of failure of deep brain stimulation
Ursachen für Misserfolge bei der Deep Brain Stimulation
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Published: | May 4, 2005 |
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Outline
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Objective
The importance of Deep Brain Stimulation (DBS) for the treatment of movement disorders is still growing. Many reports have been published so far on safety and effectiveness of DBS. In order to evaluate predictors for the outcome of DBS we retrospectively reviewed and analysed the cases of failure of DBS surgery.
Methods
Between 1996 and 2004 303 deep brain electrodes were implanted in 166 patients in two centres. Parkinson’s disease (PD) was found in 94 patients, of which the first 8 PD patients underwent GPi surgery. 15 patients with Dystonia were treated with GPi electrodes.
Results
For the evaluation of PD patients UPDRS III motor score was performed. We considered the operation as successful, if both a significant improvement in the ADL was reported by the patients and pending no permanent morbidity was determined at the 6 months follow-up. There was a significant improvement (p<0,001) in motor function (UPDRS III) for PD patients stimulated in the STN. Tremor patients also significantly benefited from surgery. In dystonia patients different results were achieved. The overall surgery related complication rates were 18% for the STN (16/86 patients, 1 intracerebral and 4 subcutaneous haemorrhages, 6 infections, 2 dislocations of electrodes, 7 permanent psychic deterioration, 5 unrelated deaths within 24 months, 11 surgical revisions), 7% for the VIM (4/57, 1 infection, 2 intracerebral haemorrhages, 1 MCA stroke, 1 related death, 1 dislocation, 1 revision) and 17% for the GPi (4/23 patients, 3 infections, 1 intracerebral haemorrhage, 3 revisions). Several reasons for failure of surgery were determined: in 2 patients Multi System Atrophy was considered retrospectively, in 2 patients effective stimulation in the STN lead to manic behaviour, 5 patients developed progressive dementia in the follow-up course. Psychotic deteriorations commonly occurred in cases of bilateral DBS in the STN (26 out of 86 patients). However, these were transient in most patients. In 5 patients permanent deficits lead to a reduction of DBS success. In 6 patients suboptimal electrode position limited the benefit from stimulation.
Conclusions
In conclusion it became obvious that careful selection of patients, accurate target determination, state of the art imaging techniques) and sophisticated neuropsychological screening are required to avoid DBS failure.