Objective: Study and correlate the distribution of the preoperative targets(PT) and the active contacts(AC) in STN DBS for PD.
Material and Methods: 23 parkinsonian patients selected for bilateral STN DBS surgery were included in this study. The final electrode (ACTIVA 3389, Medtronic) wasimplanted according to the preoperative target, intraoperative microrecording and assessment of the clinical e¤ectsof macrostimulation. The preoperative targeting of the STN wasperformed on an inversion recovery T2 weighted coronal sequence performed orthogonal to the AC-PC plane and based on visual anatomical structures surrounding the STN. The postoperative localisation of the final implanted electrodes was performed on a 3D T1-weighted gradient echo volumetric sequence and takes in consideration the study of the distortion artefact induced by the electrode ACTIVA 3389.
Results: The coordinatesof 46 PT and AC were obtained related to the midcommissural point. The mean PT was AP ¼ 2.7 (G0.9) mm, LAT ¼ 12.2 (G0.7) mm and VERT ¼ 6.3 (G1.6) mm. The mean AC wasAP ¼ 3.08 (G1.2) mm, LAT ¼ 11.9 (G1.1) mm and VERT ¼ 4.22 (G1.7) mm. According to the Schaltenbrand and Wahren atlas, the mean PT projects in the substantia nigra pars reticulata, we can expect that at least one contact of the electrode will project inside the STN. Conclusion: Considering that the distal tip of the final electrode is implanted at the target or below, study of the distribution of PT and AC shows that precision in reaching the STN seems mandatory in the selection of the active contact in STN DBS for PD.