Article
Replacing standard DBS with a directional lead system in patients with advanced essential tremor – results from the “RESCUED – trial”
Austausch von Standard-DBS Elektroden für ein direktionales System in Patienten mit fortgeschrittenem essentiellen Tremor – Ergebnisse der „RESCUED- Studie“
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Authors
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Marie T. Krüger
- Kantonsspital Sankt Gallen, Neurochirurgie, St. Gallen, Switzerland; University of British Columbia, Neurosurgery, Vancouver, Canada
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Josue Avecillas-Chasin
- University of British Columbia, Neurosurgery, Vancouver, Canada
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Christopher R. Honey
- University of British Columbia, Neurosurgery, Vancouver, Canada
| Published: | June 26, 2020 |
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Outline
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Objective: Patients with advanced Essential Tremor (ET) treated with deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) can experience reduced tremor control with progression of their disease. Initially, tremor improvement can be obtained by increasing the stimulation. Eventually, this can cause side effects as the standard lead causes unwanted stimulation of adjacent regions (e.g. internal capsule). In this study, we replaced the standard leads with directional leads in a cohort of patients with advanced ET and insufficient tremor control. This prospective trial was designed to evaluate the clinical benefits and complications of directional leads in this cohort of patients.
Methods: Six patients with advanced ET and bilateral DBS with standard leads in the VIM were entered into the study. Patients must have initially experienced optimal tremor control but later developed tremor, which could only be controlled with concurrent unwanted side-effects. Leads must have been optimally placed (post-operative CT fusion). Patients then had their standard DBS system (sDBS, Medtronic) replaced with directional leads (dDBS, Boston Scientific). Tremor rating scale (TRS) and quality of life tests were performed before and after replacement surgery. The primary endpoint was the degree of tremor reduction with no side effect for the standard and directional lead systems. The secondary endpoints were improvements in quality of life measures e.g. QUEST.
Results: When comparing the amount of tremor (OFF-ON) with no side effects before (sDBS) and after replacement (dDBS), there is a statistically significant improvement (Wilcoxon Signed-Rank Test: p< 0.05) in favour of the dDBS system. The results of the QUEST (Quality of Life in Essential Tremor Questioner) and VHI (Voice Handicap Index) show an improvement in most patients (5/6). The amount of hours needed to program the directional leads, reflect a learning curve (from 28 hours for the first to four hours for the last patient). There were no complications from surgery.
Conclusion: Directional leads can significantly improve tremor without additional side effects in advanced ET patients with VIM DBS when compared to standard DBS leads. This can improve patients’ quality of life related to their tremor and voice. Exchanging systems is a safe option for advanced ET patients. Furthermore our data supports the initial implantation of dDBS to improve patients’ tremor without side-effects in less severely affected patients at an earlier stage.
