A novel robot-guided minimally invasive technique for brain tumor biopsies

OBJECTIVE: As decisions regarding tumor diagnosis and subsequent treatment are increasingly based on molecular pathology, the frequency of brain biopsies is increasing. Robotic devices overcome limitations of frame-based and frameless techniques in terms of accuracy and usability. The aim of the present study was to present a novel, minimally invasive, robot-guided biopsy technique and compare the results with those of standard burr hole biopsy. METHODS: A tubular minimally invasive instrument set was custom-designed for the iSYS-1 robot-guided biopsies. Feasibility, accuracy, duration, and outcome were compared in a consecutive series of 66 cases of robot-guided stereotactic biopsies between the minimally invasive (32 patients) and standard (34 patients) procedures. RESULTS: Application of the minimally invasive instrument set was feasible in all patients. Compared with the standard burr hole technique, accuracy was significantly higher both at entry (median 1.5 mm range 0.2-3.2 mm vs 1.7 mm range 0.8-5.1 mm, p = 0.008) and at target (median 1.5 mm range 0.4-3.4 mm vs 2.0 mm range 0.8-3.9 mm, p = 0.019). The incision-to-suture time was significantly shorter (median 30 minutes range 15-50 minutes vs 37.5 minutes range 25-105 minutes, p < 0.001). The skin incision was significantly shorter (median 16.3 mm range 12.7-23.4 mm vs 28.4 mm range 20-42.2 mm, p = 0.002). A diagnostic tissue sample was obtained in all cases. CONCLUSIONS: Application of the novel instrument set was feasible in all patients. According to the authors' data, the minimally invasive robot-guidance procedure can significantly improve accuracy, reduce operating time, and improve the cosmetic result of stereotactic biopsies.