title: A novel miniature robotic device for frameless implantation of depth electrodes in refractory epilepsy.
abstract: OBJECTIVE The authors' group recently published a novel technique for a navigation-guided frameless stereotactic approach for the placement of depth electrodes in epilepsy patients. To improve the accuracy of the trajectory and enhance the procedural workflow, the authors implemented the iSys1 miniature robotic device in the present study into this routine. METHODS As a first step, a preclinical phantom study was performed using a human skull model, and the accuracy and timing between 5 electrodes implanted with the manual technique and 5 with the aid of the robot were compared. After this phantom study showed an increased accuracy with robot-assisted electrode placement and confirmed the robot's ability to maintain stability despite the rotational forces and the leverage effect from drilling and screwing, patients were enrolled and analyzed for robot-assisted depth electrode placement at the authors' institution from January 2014 to December 2015. All procedures were performed with the S7 Surgical Navigation System with Synergy Cranial software and the iSys1 miniature robotic device. RESULTS Ninety-three electrodes were implanted in 16 patients (median age 33 years, range 3-55 years; 9 females, 7 males). The authors saw a significant increase in accuracy compared with their manual technique, with a median deviation from the planned entry and target points of 1.3 mm (range 0.1-3.4 mm) and 1.5 mm (range 0.3-6.7 mm), respectively. For the last 5 patients (31 electrodes) of this series the authors modified their technique in placing a guide for implantation of depth electrodes (GIDE) on the bone and saw a significant further increase in the accuracy at the entry point to 1.18 ± 0.5 mm (mean ± SD) compared with 1.54 ± 0.8 mm for the first 11 patients (p = 0.021). The median length of the trajectories was 45.4 mm (range 19-102.6 mm). The mean duration of depth electrode placement from the start of trajectory alignment to fixation of the electrode was 15.7 minutes (range 8.5-26.6 minutes), which was significantly faster than with the manual technique. In 12 patients, depth electrode placement was combined with subdural electrode placement. The procedure was well tolerated in all patients. The authors did not encounter any case of hemorrhage or neurological deficit related to the electrode placement. In 1 patient with a psoriasis vulgaris, a superficial wound infection was encountered. Adequate physiological recordings were obtained from all electrodes. No additional electrodes had to be implanted because of misplacement. CONCLUSIONS The iSys1 robotic device is a versatile and easy to use tool for frameless implantation of depth electrodes for the treatment of epilepsy. It increased the accuracy of the authors' manual technique by 60% at the entry point and over 30% at the target. It further enhanced and expedited the authors' procedural workflow.
authors: Department of Neurosurgery; and.
authors: Christian
authors: C
authors: Dorfer
authors: Department of Neurosurgery; and.
authors: Georgi
authors: G
authors: Minchev
authors: Department of Neurosurgery; and.
authors: Thomas
authors: T
authors: Czech
authors: Department of Neurosurgery; and.
authors: Harald
authors: H
authors: Stefanits
authors: Departments of 2 Pediatrics and Adolescence Medicine and.
authors: Martha
authors: M
authors: Feucht
authors: Neurology, Epilepsy Monitoring Unit, Medical University Vienna.
authors: Ekaterina
authors: E
authors: Pataraia
authors: Second Neurological Department, General Hospital Hietzing, Vienna; and.
authors: Christoph
authors: C
authors: Baumgartner
authors: Austrian Center of Medical Innovation and Technology (ACMIT), Wiener Neustadt, Austria.
authors: Gernot
authors: G
authors: Kronreif
authors: Department of Neurosurgery; and.
authors: Stefan
authors: S
authors: Wolfsberger
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D046690:Deep Brain Stimulation / Q000295:instrumentation*; D000069279:Drug Resistant Epilepsy / Q000628:therapy*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D065287:Robotic Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D055815:Young Adult
keywords: EEG = electroencephalography; GIDE = guide for implantation of depth electrodes; RPU = robotic positioning unit; SEEG; depth electrodes; diagnostic and operative techniques; epilepsy; frameless stereotaxy; robot; stereo-electroencephalography