MRI-guided DBS of STN under general anesthesia for Parkinson's disease: results and microlesion effect analysis

The efficacy of the subthalamic nucleus (STN) stimulation for Parkinson's disease has been widely established. The microlesion effect (MLE) due to deep brain stimulation (DBS) electrode implantation has been reputed to be a good predictor for long-term efficacy of the procedure but its analysis in asleep implantation is still unclear. We thus analyzed MLE rate in our strategy of targeting the STN on MRI under general anesthesia and its correlation with our long-term results.

We retrospectively analyzed 32 consecutive parkinsonian patients implanted with a DBS targeting the STN bilaterally under general anesthesia between October 2013 and December 2020. Targeting was performed after head frame and localizer placement using a stereotactic peroperative robotic 3D fluoroscopy (Artis Zeego, Siemens) fused with preoperative CT and MRI data. We collected intraoperative data, postoperative occurrence of MLE, modification of Unified Parkinson Disease Rating Scale item III (UPDRS III) postoperatively and at subsequent visit, as well as reduction of medication.

The mean operative time was 223 min. No permanent complication occurred. MLE was observed in 90.7%. The mean follow-up time was 17 months. The UPDRS III for the off medication/on stimulation condition improved by 64.8% from baseline. The mean dose reduction of Prolopa after the surgical procedure was 31.3%.

Direct targeting of STN under general anesthesia based on preoperative CT and MRI data fused with a preoperative 3D fluoroscopy is safe. It allows for a high rate of postoperative MLE (90.7%) and results in prolonged clinical improvement.