Cushing disease (CD) constitutes a challenging condition for the pituitary surgeon. Given the variety of factors affecting outcomes in CD, it is uncertain whether the newer endoscopic technique improves the results of surgery.

A review was conducted of CD cases at our institution between 2000 and 2010. Analysis was done to: determine if surgical technique had an effect on outcome, identify the predictors of outcome and provide details of failed cases. Remission was defined as normal postoperative 24-hour urinary free cortisol (24-h UFC), suppression of morning serum cortisol to <50 nmol/L after 1mg of dexamethasone or being dependent on steroid replacement.

Forty-two patients met our inclusion criteria. Average follow-up period was 33 months. There were 15 macroadenomas and 27 microadenomas. Seventeen patients had an endoscopic transsphenoidal surgery and twenty-five patients had a microscopic transsphenoidal procedure. Long-term overall remission was achieved in 26 (62%) patients. There was no significant difference in remission rates between the two techniques (p value 0.757). Patient's subjective symptomatic improvement and drop of morning serum cortisol in the postoperative period to less than 100 nmol/L correlated with long-term remission (p value 0.0031and 0.0101, respectively) while repeat surgery was the only predictor of the lack of postoperative remission (p value 0.0008).

Revision surgery predicted poor remission rate for CD. Within the power of our study size, there was no difference in outcome between the endoscopic and microscopic approaches. Surgical outcomes should be reviewed in association with remission criteria used in a study.