Intraoperative MRI in pediatric brain tumor surgery: Optimizing surgical decision-making and extent of resection

Abstract Objective To assess the impact of intraoperative MRI (ioMRI) on the extent of resection (EoR) in pediatric brain tumor surgery and evaluate the benefits and limitations of its routine implementation. Methods Observational single-center study, including prospectively collected data of 118 ioMRI-guided intracranial tumor resections in 108 children that were performed at the University Hospital Zurich between May 2013 and October 2022. EoR was graded as gross total (GTR; no residual tumor), sub-total (STR; > 90% tumor resection), and partial resection (PR; < 90% tumor resection). Results A total of 118 ioMRI-guided interventions were performed in 108 individual children aged ≤ 18 years. The intended EoR determined pre-operatively was GTR in 81 cases (68.6%), STR in 24 (20.3%), and PR in 13 (11.0%). IoMRI confirmed the intended EoR achieved in 78/118 procedures (66.1%), demonstrating GTR in 48 cases (40.7%), STR in 50 (42.4%), and PR in 20 (16.9%). In 48 cases (40.7%), ioMRI findings prompted further intraoperative evaluation; additional tumor resection was performed in 45 cases (93.8%), resulting in improved EoR. The final EoR distribution after ioMRI-guidance was 80 GTR (67.8%), 25 STR (21.2%), and 13 PR (11.0%), resulting in a rate of achieving the intended EoR in 99.2% of cases (117/118). Surgical site infections (SSI) occurred in 4 cases (3.4%). Conclusions This study highlights the substantial impact of ioMRI in pediatric brain tumor surgery, demonstrating a high rate of surgical site reopening for residual tumor resection, which substantially improved the EoR and minimized the need for a second operation – without increasing SSI incidence.