Artikel
Directional deep brain stimulation: An intraoperative double-blind pilot study
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Veröffentlicht: | 13. Mai 2014 |
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Gliederung
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Objective: Although DBS has shown to drastically improve symptoms of a variety of neurological conditions, the occurrence of acute disabling or even chronic side effects may limit the ability to deliver adequate current necessary to reach the maximal benefit. Computed models have suggested that reduction in electrode size and the ability to provide directional stimulation could increase the efficacy of DBS therapies. However, this has never been demonstrated in human. The objective of the present study is to assess the effect of directional stimulation on the current threshold window between positive and side effects, defined as the therapeutic window (TW), compared to omnidirectional stimulation.
Method: We applied directional stimulation intraoperatively in the STN of 11 patients with Parkinson’s disease and in the Vim of 2 with essential tremor selected to undergo DBS. 3 different directions of stimulation as well as omnidirectional stimulation were assessed at the trajectory chosen for implantation of the definitive electrode with increments of 0.1 mA.
Results: All but one patient, showed a benefit of directional stimulation compared to omnidirectional. A best direction of stimulation was observed in all the patients. The TW in the best direction of 1.93 mA:1.0-2.9 mA) was wider (p = 0.003) than the 2nd best direction (1.43 mA:0.2-2.9mA) and than the 3rd best direction (0.96mA:0-2.1mA) (p=0.002). Compared to omnidirectional direction, TW in the best direction was 41.3% wider (p=0.037). The current threshold producing meaningful therapeutic effect in the best direction was 0.67 mA (0.3-1.0 mA) and was 43% lower (p=0.002) than in omnidirectional stimulation. No complication due to insertion of the directional electrode or stimulation were encountered in the directional test phase.
Conclusions: Intraoperative directional DBS applied in the STN and the Vim with a reduced electrode size significantly widened the therapeutic window and lowered the current needed for beneficial effects, compared to omnidirectional stimulation. The observed side effects related to direction of stimulation were consistent with the anatomical location of surrounding structures. This new approach opens the door to an improved DBS therapy. Chronic implantation is further needed to confirm these findings