Orbital resection by intranasal technique (ORBIT): a new classification system for reporting endoscopically resectable primary benign orbital tumors

Background: The Cavernous Hemangioma Exclusively Endonasal Resection (CHEER) staging system has become the gold standard for outcomes reporting in endoscopic orbital surgery for orbital cavernous hemangiomas (OCHs). A recent systematic review demonstrated similar outcomes between OCHs and other primary benign orbital tumors (PBOTs). Therefore, we hypothesized that a simplified and more comprehensive classification system could be developed to predict surgical outcomes of other PBOTs. Methods: Patient and tumor characteristics as well as surgical outcomes from 11 international centers were recorded. All tumors were retrospectively assigned an Orbital Resection by Intranasal Technique (ORBIT) class and stratified based on surgical approach as either exclusively endoscopic or combined (endoscopic and open). Outcomes based on approach were compared using chi-squared or Fisher's exact tests. The Cochrane-Armitage test for trend was used to analyze outcomes by class. Results: Findings from 110 PBOTs from 110 patients (age 49.0 ± 15.0 years, 51.9% female) were included in the analysis. Higher ORBIT class was associated with a lower likelihood of gross total resection (GTR). GTR was more likely to be achieved when an exclusively endoscopic approach was utilized (p < 0.05). Tumors resected using a combined approach tended to be larger, to present with diplopia, and to have an immediate postoperative cranial nerve palsy (p < 0.05). Conclusion: Endoscopic treatment of PBOTs is an effective approach, with favorable short-term and long-term postoperative outcomes as well as low rate of adverse events. The ORBIT classification system is an anatomic-based framework that effectively facilitates high-quality outcomes reporting for all PBOTs.