Efficacy and Complications of Endoscopic Skull Base Surgery for Giant Pituitary Adenomas

OBJECTIVE: We report surgical results and complications of endoscopic endonasal skull base surgery for giant pituitary adenomas. METHODS: This study included 34 pituitary adenomas >40 mm treated by endoscopic endonasal skull base surgery between 2002 and 2015. Removal rates, symptoms, and complications were analyzed by direction of tumor extension. RESULTS: Average tumor size was 45.5 mm. Near-total resection was achieved in 16 of 34 (47.1%) cases. Neartotal resection was achieved significantly more often in anterior extension types and round tumor in superior extension types compared with multiple extension types. The average residual amount in 18 partial resection cases was 30.2% of preoperative volume, with no significant difference between groups. Regrowth after partial resection occurred in 8 cases, but repeated surgery or stereotactic radiotherapy controlled tumor growth and improved symptoms. Postoperative improvement of visual field deficits was achieved in 23 of 25 (92.0%) cases. Postoperative complications included visual deterioration (n = 1), cerebrospinal fluid leakage (n = 2), and cerebral infarction secondary to perforator injury (n = 2). Symptomatic intratumoral hemorrhage occurred in 1 multiple extension type. CONCLUSIONS: Endoscopic endonasal skull base surgery enables less invasive and safer removal of various extension types of giant pituitary adenomas. Preservation of visual function is essential. Two-stage surgery or partial resection with additional treatments is possible without complications if a sufficient amount of resection is performed. In cases in which insufficient resection may be expected, alternative treatment, including combined-simultaneous resection, should be considered.