Unexpected Residual After Endoscopic Trans-Sphenoidal Surgery For Large And Giant Pituitary Adenomas
Kevin Kwan, Timothy White, Ivo Peto, Hussam Abu-Al-Shaar, Amir Dehdashti, Mark Eisenberg, Katie Wagner
Introduction: Large (>3cm) and giant (>4cm) pituitary adenomas pose a surgical challenge resulting in resection rates lower than other adenomas. Incomplete resection is usually seen with tumor lateral extensions, encasement of vital neurovascular structures or cavernous sinus where a residual is considered expected.
Objective: This study analyzes risk factors for presence and outcomes of unexpected residuals after endoscopic endonasal surgery.
Methods: A retrospective analysis of all patients with giant and large adenomas operated between 2015 and 2018 was performed. Patient demographics, surgical and radiological variables were analyzed, including suprasellar dimensions, tumor histology, MRI appearance, and endocrinological and visual status.
Results: Forty patients were included in the analysis comprising 30 large and 10 giant adenomas. The mean age was 57.85 years. The mean MRI follow-up was 5.9 months post-resection. In patients with large tumors, gross total resection (GTR) was achieved in 25 patients(83.3%), subtotal resection(STR) in four(13.3%) and inconclusive in one(3.3%). In patients with giant tumors, GTR was achieved in 5 patients (50%), STR in 4(40%) and inconclusive in one(10%). Residual tumors were identified in 9(22.5%), of which 7(77.7%) were unexpected. Increased longest working distance(LMax) was significantly associated with residual tumor(p=0.049). Association of unexpected residual tumor with larger retrosellar extension and increased LMAx were observed(p=0.003, p=0.018).
Conclusions: Large and giant adenomas are challenging lesions with high incomplete resection rates. The length of the working distance and retrosellar extension of the tumor seem to be associated with increased frequency of residual in these tumors. Prospective multicentric studies are needed to elucidate contributing factors associated with unexpected residuals.