O-ARM Stereotactic Imaging in Deep Brain Stimulation for Parkinson's Disease (STEREOBLOC)

Evaluation of Intraoperative O-ARM Stereotactic Imaging Versus Conventional Pre-operative Stereotactic Imaging in Deep Brain Stimulation for Parkinson's Disease

During deep brain stimulation procedures in Parkinson's disease (PD), the most important prognostic element is the positioning of the surgical electrode in the subthalamic nucleus which is the anatomical target. The main objective of this project is therefore to compare 2 techniques thanks to a prospective comparative randomised open-label study: the use of O-ARM to acquire stereotactic imaging directly in the operating room and the standard technique requiring stereotactic imaging to be performed in the radiology department.

Prior to electrode implantation we perform stereotactic imaging which requires the fixation of a stereotactic frame on the patient's head before imaging (Magnetic Resonance Imaging MRI / Computed Tomography CT). Currently, it is necessary to transfer the patient to the imaging department outside of the operating room after the stereotactic frame has been placed, for imaging (either MRI or CT) and then to return to the operating room to begin the electrode implantation procedure. Since 2016, the new generation O-Arm 2 allows the acquisition of stereotactic imaging with the stereotactic frame in place by increasing the field of view (40 cm versus 20 cm previously) directly in the operating room. As a result, the transfer step to the MRI and CT scanner preoperatively may no longer be necessary, and the procedure can be started more quickly with greater comfort and safety for the patient and the anaesthesia team. Several teams around the world have begun to use framed O-Arm as the gold standard for stereotactic imaging. However, no randomised controlled study has been performed to date comparing O-Arm stereotactic imaging with pre-operative CT and/or MRI reference imaging.

The radial distance between the theoretical target and the electrode in the plane of the target regardless of the chosen trajectory (central, anterior, lateral). This distance corresponds to the minimum error between the target and the electrode. This measurement is made from the postoperative brain scan.

Automatic calculation of the vector distance between the middle of pad 1 on the electrode and the theoretical target by logicial.

Comparison of the anatomical location of the electrode compared to the anatomical target (subthalamic nucleus) after matching preoperative Magnetic Resonance Imaging (MRI) images

Time from the end of the stereotactic frame to the surgical incision and time from the entry into room to the exit from room after generator implantation.

Comparison of The Unified Parkinson's Disease Rating Scale (UPDRS) II, III and IV scores between baseline and 6 months and then at 6 months between the 2 groups. The UPDRS scale is composed of 47 items grouped into three parts : II, III and IV. Responses scale ranging from 0 (normal/no symptoms) to 4 (severe).

The change in Levodopa Equivalent Daily Dose (LEDD) before surgery and at 6 months compared between the 2 groups. This LEDD corresponds to the amount of antiparkinsonian treatments prescribed to the patient

Inclusion Criteria: Patients with a diagnosis of idiopathic Parkinson's disease at the stage of motor fluctuations despite optimal medical treatment Indication for Deep Brain Stimulation (DBS) of the subthalamic nucleus approved by the local multidisciplinary deep brain stimulation committee after an operability assessment (see Appendix) Informed and signed patient consent Affiliation to a social security scheme Exclusion Criteria: Significant cognitive decline assessed in a dedicated multidisciplinary consultation Contraindication to Magnetic Resonance Imaging (MRI) Presence of pathologies contraindicating deep brain stimulation No contraceptive treatment for women of childbearing age Pregnant or breastfeeding woman Anticoagulant or antiaggregant treatment that cannot be stopped Persons under legal protection (persons deprived of liberty or incapable of giving consent or under guardianship or tutelage...) Patient with severe psychiatric disorders