Comparison of the Outcomes of Endoscopic and Microscopic Surgery in Cushing's Disease

Background: Cushing's disease (CD) constitutes a challenging condition even for the experienced pituitary surgeon. It is uncertain whether the endoscopic technique has improved the results compared with the traditional microsurgical technique.

Methods: A retrospective review was conducted for CD cases at our institution between 1998 and 2010. Patients' charts were reviewed for demographic, clinical, laboratory, and radiological details in all cases. We also reviewed surgical technique and outcome. Analysis was done to identify predictors of outcome and the details of failed cases. Remission was defined as normal postoperative 24-hour urinary free cortisol (24-h UFC) or suppression of morning serum cortisol to <50 nmol/L after 1 mg of dexamethasone.

Results: Forty-two patients met our inclusion criteria. Thirty-one (74%) were women. The average age of the patients was 50 years (range, 20–69 years). Eighteen patients (43%) had a microadenoma, 15 patients (36%) had a macroadenoma, and 9 patients (21%) showed no evidence of an adenoma on MRI. The surgeon identified a pituitary adenoma intraoperatively in 37 cases. Thirty-sex patients had selective adenomectomy and 6 patients had hypophysectomy. Seventeen patients had an endoscopic transsphenoidal surgery (endo TSS) and 25 had microscopic transsphenoidal procedure (micro TSS). Remission was achieved initially in 31 patients, while long-term remission was achieved in 29 (69%) patients. Repeat transsphenoidal surgery and cavernous sinus (CS) invasion predicted lack of postoperative remission (P value < 0.0001 and 0.0249, respectively). Patients' subjective symptomatic improvement and drop of serum cortisol in the postoperative period to less than 100 nmol/L correlated with long-term remission (P values < 0.0001 and 0.0046, respectively). There was no significant difference in remission rate between the endo TSS and the micro TSS (P value 0.5046). Average follow-up period was 33 months (range, 3–102 months).

Conclusions: Revision surgery and CS invasion predicted poor remission rate for CD. Within the size of our study, there was no difference in outcome between endo TSS and micro TSS.