Abstract
INTRODUCTION One reason neurosurgeons have adopted fully endoscopic transsphenoidal surgery over microscopic surgery is that the visualization advantages (ie, panoramic and angled viewing, high magnification, superior illumination) are thought to translate into improved extent of tumor resection. An analysis of the primary endpoint of the TRANSSPHER study demonstrated that unadjusted rates of gross total tumor removal (GTR) versus subtotal removal were similar, with a trend toward better GTR rates in the endoscopic cohort in tumors with cavernous sinus invasion. In this abstract, we evaluate the volumetric extent of tumor resection. METHODS The TRANSSPHER study is a prospective controlled outcomes study comparing endoscopic and microscopic transsphenoidal surgery. Volumetric extent of tumor resection was determined at the coordinating site using manual segmentation of preoperative and postoperative pituitary contrasted MRI scans by reviewers blinded to surgical technique. RESULTS A total of 259 patients were treated by 15 surgeons (11 endoscopic, 4 microscopic) at 7 US pituitary centers between February 2015 and June 2017. A total of 240 patients (92.7%) were available for follow-up. The 2 cohorts were similar with respect to patient demographics (P > .51) and Knosp grade (P = .80); however, the microscopic surgeons were more experienced as measured by career number of cases (P = .001). Preoperative tumor volumes were similar (endoscopic 7.1 cm3 ± 5.7 vs microscopic 7.4 cm3 ± 7.8, P = .25). There were no differences in percent tumor removed (98.1% ± 5.7 vs 97.6% ± 7.7, P = .51), volume of residual tumor (0.24 cm3 ± 0.96 vs 0.26 cm3 ± 0.84, P = .86), and percentage of patients with near-total resections (>90% resection) (154/165 [93.3%] vs 68/75 [90.7%], P = .44). Planned subgroup analyses of Knosp grade 3-4 tumors (93.6% vs 91.5%, P = .61) and large tumors (>3 cm) (95.9% vs 97.0%, P = .52) demonstrated no significant differences. CONCLUSION This unadjusted analysis does not support the hypothesis that endoscopic visualization improves extent of tumor resection over microscopic surgery for nonfunctioning adenomas. A multivariate analysis of independent predictors of extent of resection is forthcoming.