Virtual reality based quantitative evaluation of the effect of orbitotomy on frontal lobe retraction during tuberculum sellae meningioma surgery

This study aimed to evaluate the effects of orbitotomy on tuberculum sellae meningioma surgery using the supraorbital approach through a quantitative assessment of brain retraction and stratified effect by tumor size. An in-silico study was conducted using three-dimensional (3D) head models generated from the imaging data of 35 patients (70 hemispheres) without brain deformation, created with a surgical simulation software (GRID, Kompath Inc., Tokyo, Japan). A skull base tumor model was created by inserting virtual hemispherical tumors of varying diameters (20, 30, 40, and 50 mm) into the tuberculum sellae within the 3D model. Supraorbital craniotomy was performed on the skull base tumor model, and the distance of frontal lobe retraction required to access the tumor apex was measured with and without orbitotomy. Imaging data from 35 patients (70 hemispheres) revealed that orbitotomy statistically reduced frontal lobe retraction by 0.8 mm for 20 mm tumors, 1.55 mm for 30 mm tumors, 2.8 mm for 40 mm tumors, and 3.31 mm for 50 mm tumors (p < 0.01 for all findings). A comparison of the effects of orbitotomy according to tumor size showed the highest impact on tumors larger than 40 mm. This study quantified changes in brain retraction associated with adding orbitotomy for tumors of various sizes. These findings provide specific estimates for each tumor size, serving as a guideline for determining the indications for orbitotomy and contributing to optimizing skull base surgical approaches.