Endoscopic-approach development for minimally invasive orbital surgery

Purpose: Orbital tumors and pseudotumor cerebri are sometimes treated with surgical approaches. Our previous studies suggest that potentially endoscopy may be useful for minimally invasive orbital surgery. This study proposed to improve the approach technique for accessing the posterior orbital space via endoscopy, as well as assess visibility improvements with CO 2 insufflation to posterior orbital tissues. Methods: An inferior transconjunctival approach accessed the posterior orbital space in non-survival pigs. Various guidance tubes were compared to assess ability to guide the endoscope to the posterior orbit with the greatest ease and visibility. FEL energy application (6.1 mm, 2.7 ± 0.5 mJ, 30 Hz, delivered via glass-hollow waveguide) was attempted via endoscopy. The effect of CO 2 gas insufflation was assessed by analyzing visibility of the stuctures before and after CO 2 application. Results: The posterior orbit was accessed via endoscopy in all except the first attempted eye. A beveled transparent butyrate tube provided the best guidance for the endoscope and an opaque metal tube provided the worst guidance. The optic nerve was encountered and FEL energy was applied with the butyrate tube in 8 orbits. Visibility was adequate without CO 2 insufflation, and did not improve with CO 2 . Conclusions: The posterior orbit was successfully accessed using endoscopy. The optic nerve was exposed and treated with FEL energy. CO 2 insufflation did not further enhance visibility in this study. Application of endoscopy for posterior orbital procedures is feasible, but extreme surgical care is required and further study with human cadaveric eyes is needed.