Endoscopic Transsphenoidal Surgery Outcomes in 331 Nonfunctioning Pituitary Adenoma Cases After a Single Surgeon Learning Curve

OBJECTIVE: The outcomes of recent endoscopic surgery of nonfunctioning pituitary adenomas (NFPAs) are controversial when compared with traditional microscopic surgery. We aimed to assess the outcomes of endoscopic transsphenoidal surgeries performed by 1 surgeon with 7 years of experience and elucidate the predictive factors for surgical outcomes for NFPAs. METHODS: We included 331 patients (155 men and 176 women) with clinical NFPAs who underwent transsphenoidal surgery because of visual symptoms by a single surgeon in Seoul National University Hospital from March 2010 to May 2016. We assessed the tumor removal rate, hormonal outcomes, visual outcomes, and complications. RESULTS: The gross total resection rate of endoscopic transsphenoidal surgery for NFPAs by a single surgeon was 74.9%. Cavernous sinus invasion, a high Knosp grade, large tumor size, previous surgery, and lack of surgical experience in the neurosurgeon elevated the risk for residual tumors. Visual deficits were improved in 73.4% of the patients, which was associated with tumor size, preoperative visual impairment score, previous radiation, and surgical experience. Hormonal status was improved in 15.4% and aggravated in 32.9% after surgery. There were no predictors for hormonal recovery. Transient diabetes insipidus (DI) was the most common complication (9.1%), and among these patients, 3.0% had persistent DI. CONCLUSIONS: Endoscopic transsphenoidal surgery by a well-experienced surgeon was an effective and safe treatment for NFPAs, but the hormonal outcomes were not changed compared with previous reports of microscopic surgery. Large tumor size and cavernous sinus invasion were still the barriers for achieving total resection.