Figure 3.

(A) Required stereotactic equipment for the procedure: 2.15 mm PEEK ROSA adapter, 190 mm length slotted canula, RNS depth electrode, stereotactic ruler, bent cranial plate and cut segment of lead cap. The depth electrode is marked at three points: 190 and 200 mm, which flank the wide hub of the cannula, and the point corresponding to the outer table of the skull, measured on the stereotactic plan. This last point is important to mark, as it is the only one visible once the cannula is removed and the robot arm moved away. (B) After the electrode is inserted, a dog-bone cranial fixation miniplate is fastened to the skull to hold the electrode in place. We use the cut segment of the lead cap as a shock absorber around the lead. (C) After creating the craniectomy and securing the ferrule, the RNS leads are retrieved from their subgaleal position. (D) The RNS generator can be placed and connected to the depth electrodes. This can be performed either in the same prone position or after re-positioning the patient supine with the head turned.