gms | German Medical Science

Objective: In the last few years the number of patients requiring stereoelectroencephalography (SEEG) investigations as part of their presurgical work-up increases in all epilepsy centers in Germany. Most recently, robot-assisted procedures have attracted considerable attention and have in some centers replaced the more traditional frame-based stereotactic operations. Here we report our institutional experience with frameless robot-assisted stereotactic placement of intracerebral depth electrodes using the NeuromateRrobot.

Methods: Between August 2015 and October 2017 28 consecutive patients underwent robot-assisted stereotactic placement of intracerebral depth electrodes for extraoperative epilepsy monitoring. We specifically focused on the accuracy of the robot-assisted procedure. After fusion of the pre- and postsurgical MRIs the coordinates of the planned and actual entry and target points were defined and the respective deviations calculated as the Euclidean distances. The time between placement of the MRI reference-screw and end of placement of the last electrode was recorded as "operative time".

Results: 174 depth electrodes were implanted in 28 patients (mean 6 per patient, range 1-11). There were 9 female and 19 male patients. Mean age was 24 (3.6-61.4) years. Mean electrode length was 40.2 (12-97) mm. The mean entry point error was 1.72 (0.00-4.52) mm. The mean target point error was 1.95 (0.00-4.43) mm. In one case the postoperative MRI showed a small subdural hematoma without clinical relevance. There were no infectious complications. Mean time for the placement of one electrode was 40 (23.6-71.3) min. and operative time per electrode decreased with higher numbers of electrodes placed during the procedure.

Conclusion: The present study describes one of the largest patient series using frameless robot-assisted stereotactic placement of depth electrodes reported so far. The technique appears to be very safe. The accuracy of the procedure is comparable to traditional frame-based stereotactic operations [1]. In patients who require placement of a high number of electrodes the robot-assisted procedure may be less time-consuming than frame-based surgery.