Évaluation de la stimulation du noyau sous-thalamique utilisant un cadre de Fischer adapté, un guidage par fusion IRM-scanner et un contrôle radiographique stéréotaxique peropératoire, dans la maladie de Parkinson

Abstract Background We present the method and results of an original technique to implant electrodes in the subthalamic nucleus (STN) to treat Parkinson's disease, based on adaptations of the Fisher ZD stereotactic frame. Methods Targets coordinates were calculated after fusion of stereotactic CT-scan and MRI images. STN was localized by its theoretical coordinates according to AC–PC and by its direct visualization on T2 images. Electrodes were implanted after local anesthesia, using peroperative multicanal microrecordings and test stimulation. Electrodes location was checked by peroperative perpendicular radiographs. To avoid projection of the frame arm on the area of interest on anteroposterior and lateral radiographs, the arm was fixed at 45° from the usual 90° position. This original fixation needed a trigonometric transformation of the X and Y stereotactic coordinates. Radiopaque markers, fixed on the frame, were identified on the radiographs, allowing the calculation of the stereotactic coordinates of the electrode tip, which were then entered in the stereotactic MRI, to check its location from the defined target. Results No problem due to adaptations of the frame occurred in the 60 patients. In all cases, peroperative radiographs allowed to confirm the correct location of electrodes. Six months after surgery, UPDRS III score without medication was decreased by 52% with stimulation “on”. UPDRS IV items 32, 33 and 39 scores were decreased by 75,7, 79,5 and 72%. Daily dopa-equivalent dose was decreased by 71%. One asymptomatic thalamic hematoma and two wound infections occurred. Conclusion This method was efficient and safe to implant deep electrodes.