Artikel
BS electrode implantation of the posterior subthalamic area for treatment of essential tremor: proposal of MRI-based anatomical landmarks
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Autoren
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Andreas Nowacki
- Department of Neurosurgery, Inselspital, University Hospital Bern, and University of Bern, Bern, Switzerland, Bern, Switzerland
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Ines Debove
- University Hospital Bern, Bern, Switzerland
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Markus Florian Oertel
- Klinik für Neurochirurgie, Universitätsspital Zürich, Universität Zürich, Zürich, Switzerland
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Michael Schuepbach
- Universitätsklinik für Neurologie, Zentrum für Bewegungsstörungen, Bern, Switzerland
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Claudio Pollo
- Bern, Switzerland
| Veröffentlicht: | 9. Juni 2017 |
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Gliederung
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Objective: Deep Brain Stimulation (DBS) is an approved treatment option for therapy of refractory essential tremor (ET). Although evidence exists about its therapeutic effect, the optimal location of stimulation to improve tremor is still a matter of debate. Apart from the Ventral Intermediate Thalamus (VIM), the posterior subthalamic area (PSA) including the Dentato-Rubro-Thalamic-Tract (DRTT) has more recently been proposed as an appropriate target. The objective of our study is to present our MRI-based targeting procedure and correlate it with the stimulation site, clinical outcome and DTI-based fiber tracking identification of the DRTT.
Methods: We present a prospective series of 9 patients with unilateral or bilateral DBS implantation in the PSA. T2-weighted MRI was used to target the PSA on axial slices 2-3 mm below midcommissural point (MCP) within the white matter between red nucleus and subthalamic nucleus using iPlan Net 3.0 (BrainLab). Fiber tracking of the DRTT was performed in each patient. Stimulation site was obtained by calculation of the position of the active contact and its corresponding Volume of Tissue Activated (VTA). Active contact positions and VTA were correlated to clinical outcome.
Results: The mean position of the active contact was LAT 10.54; AP -3.80 and VERT -1.59 mm with reference to MCP. Projection of the mean active contact position and its corresponding VTA onto the Morel stereotactic atlas revealed a stimulation site within the PSA in the proximity of the DRTT. This was correlated to DTI fibertracking. DBS resulted in 60% tremor reduction 3-6 months postoperatively on the Fahn–Tolosa–Marin Tremor Rating Scale (p<0.0001, two-way-ANOVA).
Conclusion: DBS of the PSA is effective in the treatment of ET. Our MRI-based anatomical landmarks seem to be reliable to target the PSA in each individual case. Our DTI findings suggest that the DRTT is involved in the efficacy of PSA DBS, although DRTT is not clearly identifiable in each patient.
