Surgical outcome of endoscopic endonasal approach as a modality of management for large and giant pituitary adenomas: a retrospective case series

Large and giant pituitary adenomas (defined as tumors of maximal diameter ≥ 3–3.9 cm and ≥ 4 cm, respectively) present considerable surgical challenges regarding the extent of resection and perioperative morbidity. Endoscopic endonasal resection is considered the most effective treatment for pituitary adenomas. It allows for better visualization, maneuverability, and access to distant and lateral tumor compartments, ultimately enhancing the extent of resection. This article evaluates our initial experience with endoscopic endonasal resection of large and giant pituitary adenomas. The clinical outcomes, perioperative complications, and extent of tumor resection would be specifically addressed. The primary goal of surgery was to decompress the optic pathways, and the secondary goals were to achieve maximal safe resection and hormonal control in hormone-secreting adenomas. The degree of tumor resection was classified as gross-total resection (100%), near-total resection (90–100%), subtotal resection (70–90%), and partial resection (< 70%). 42 patients were included in this study. A good visual outcome achieved with 80% improvement in visual symptoms. Gross-total resection (GTR) was achieved in 19 patients (45.2%), near-total resection (NTR) was achieved in 12 patients (28.6%), subtotal resection (STR) in 6 patients (14.3%), and partial resection in the remaining 5 patients (11.9%). Subgroup analysis revealed that GTR, NTR rates were higher in large, compared to giant tumors. GTR, NTR rates of large adenomas were 59.3%, and 29.6%, compared to 20%, and 26.7% in giant adenomas respectively (p-value: 0.01428). Surgical complications were observed in 19 patients (45.2%) with CSF leakage being the most common complication (11 patients, 26.2%). Post-operative diabetes insipidus was observed in 5 patients (11.9%), major vascular injury in one case (2.4%), transient post-op 6th nerve palsy observed in 3 patients (7.1%), while two patients (4.8%) presented with post-operative paranasal sinuses infection. Endoscopic endonasal transsphenoidal resection of large and giant pituitary adenomas is a safe and efficient procedure. Large adenomas (3–3.9 cm) have excellent resection rates and lower complications than giant adenomas (≥ 4 cm), which may require extending our approach to achieve more tumor resection rates in the future. However, only adequate resection of these giant adenomas can be enough to achieve the main surgical goals of visual improvement, hormonal control, and decompression of surrounding structures.