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.