gms | German Medical Science

Objective: Exoscopic 3D4K video systems (EX) have recently been introduced as an alternative to conventional operating microscopes (OM). However, experience in handling and setup remains scarce and superiority to OM has not yet been proven, inciting skepticism of the new technology. EX digital fluorescence modes may facilitate glioma resection, however it is unknown how this affects outcome. This study evaluated the practicability of exoscopic surgery in a wide range of cranial procedures, focusing on digital fluorescence guided resection of primary GBM.

Methods: All operations performed at a single neurosurgical center between 08/2018 and 05/2020 were evaluated. Exoscopic tumor resections were compared with operations using OM during the same period. Patient positionings, surgeons’ comfort and fluorescence modes including ICG and 5-ALA were evaluated in a wide range of neurosurgical approaches. Duration of surgery, tumor localization and size, type of surgical approaches, extent of resection and postoperative deficits were assessed statistically as well as handling and optical issues by a standardized questionnaire. Follow-up data and extent of resection (EOR) by post-op MRI were analyzed for primary GBM.

Results: During this period, 513 EX operations were performed and compared to 101 OM surgeries. EX was generally rated as a valuable surgical tool, 3D optics in white light and fluorescence imaging were rated similar to conventional OM. EX operations were performed in 30 cases of metastases and 18 of recurrent glioma. EX resection of primary GBM occurred in n=8 cases using 5-ALA fluorescence. The median follow-up time was 161 days (range 114 – 208 days), 2/8 patients died after 31 and 303 days, respectively. Radiographic extent of resection, time of hospitalization, steroid use and median duration of operation (EX 156 min – OM 154 min) proved identical to conventional OM in primary GBM patients.

Conclusion: EX has been used and well established for a significant number of neurosurgical procedures. While presuming that the technical methodology as such when achieving identical EOR will not influence outcome of glioma surgery, proof of equipoise between different techniques expands the spectrum of surgical environments so that neurosurgeons have a choice to work according to their preferred ergonomics.