Authors: Jianning Shao; Nathan Radakovich, BA; Hamid Borghei-Razavi, MD; Krishna Joshi, MD; Baha'eddin Muhsen, MD; Bryan Lee, MD; Gene Barnett, MD; Alireza Mohammadi, MD (Cleveland, OH)

Introduction: Stereotactic laser ablation (SLA) is a novel, minimally invasive alternative to surgical resection for intracranial lesions, especially in patients with poor functional status and tumors close in proximity to eloquent structures. However, this technique is not uniformly optimal for all patients. As one of the first institutions to adopt this technology, we present a comprehensive case series detailing the evolution of patient selection, surgical trends, and lessons learned over the past decade in the largest patient cohort on SLA treatment in brain tumors to date. Methods: Retrospective review was performed on 240 patients with various brain tumors treated with SLA. Extensive data on patient demographics, surgical and tumor characteristics, temporary (resolved within 6 months) and permanent complications, and follow-up data were collected. Consecutive patients were categorized into two time periods (2011-2014, 102 patients; 2015-2018, 138 patients), and statistical analysis was performed for both time periods. Results: Initially, SLA was predominantly utilized for upfront and recurrent gliomas (76.64%); recently, however, there has been a marked increase in SLA usage for metastases and radiation necrosis following radiosurgery failure (25 combined cases --> 58 combined cases; 23.4% --> 42.65%). Additionally, there is a trend against SLA usage for large tumors (diameter > 4cm, 15.65% --> 9.57%) due to poorer outcomes associated with these lesions. Surgically, advances in SLA technology led to shorter operation times (6.25 hours --> 3.6 hours) and better separation between tracts and the hyperthermic field, ultimately resulting in fewer temporary (39.17% --> 30.1%) and permanent (13.3% --> 7.5%) postoperative deficits. Lastly, better patient selection resulted in a lower mortality rate (4.17% --> 0.83%). Conclusion: Our study shows that the evolution of SLA usage at a single institution led to better patient selection and maturation of surgical panning, ultimately resulting in fewer complications and better outcomes.