It is unclear whether endoscopic transsphenoidal surgery (ETSS) or microsurgical transsphenoidal surgery (MTS) is a superior surgical approach for pituitary adenomas.

The objective of the study was to compare the outcome of surgery with ETSS and MTS by experienced pituitary surgeons using criteria of remission using current consensus criteria for acromegaly.

This was a retrospective review of prospectively recorded outcomes. The study was conducted at a tertiary referral center.

Remission was defined as a normal IGF-I level and either suppressed GH less than 0.4 ng/mL during an oral glucose tolerance test or random GH less than 1.0 ng/mL. The Youden indices were calculated to determine the optimal cutoffs for using immediate postoperative GH levels to predict the results of later testing for remission.

Preoperative demographics and tumor characteristics were not significantly different between patients undergoing ETSS (72 patients) or MTS (41 patients). Overall, postoperative remission was achieved in 20 of 23 microadenomas (87%) and 59 of 90 macroadenomas (66%). Remission rates and perioperative complications were not significantly different between ETSS and MTS groups, except for self-reported sinusitis and alterations in taste or smell, which were significantly higher in patients treated with ETSS. Preoperative variables predicting remission in multivariate analysis included GH less than 45 ng/mL [odds ratio (OR) 6.4, P = .010)] and Knosp score of 0–2 (OR 6.8, P < .001). Postoperative in-hospital GH less than 1.15 ng/mL provided the best predictor of remission (OR 7.7, P < .001; sensitivity of 73%, specificity of 85%) defined by follow-up testing.

Outcomes of transsphenoidal surgery for acromegaly by experienced pituitary surgeons do not differ between endoscopic and microscopic techniques. Regardless of the mode of resection, patients with high preoperative GH levels and Knosp scores are less likely to achieve remission. An immediate postoperative GH level of less than 1.15 ng/mL provides the best immediate predictor of remission, but long-term outcomes are indicated.