Endoscopic Transsphenoidal Pituitary Surgery: Evidence of an Operative Learning Curve

BACKGROUND: The use of the fiberoptic endoscope is a recent innovation in pituitary surgery. OBJECTIVE: To investigate the evidence of an operative learning curve after the introduction of endoscopic transsphenoidal surgery in our unit. METHODS: The first 125 patients who underwent endoscopic transnasal transsphenoidal surgery for pituitary fossa lesions between 2005 and 2007 performed by 1 surgeon were studied. Changes in a number of parameters were assessed between 2 equal 15-month time periods: period 1 (53 patients) and period 2 (72 patients). RESULTS: There were 67 patients (54%) with nonfunctioning adenomas, 22 (18%) with acromegaly, and 10 (8%) with Cushing's disease. Between study periods 1 and 2, there was a decrease in the mean duration of surgery for nonfunctioning adenomas (from 120 minutes to 91 minutes; P < .01). This learning effect was not apparent for functioning adenomas, the surgery for which also took longer to perform. The proportion of patients with an improvement in their preoperative visual field deficits increased over the study period (from 80% to 93%; P < .05). There were nonsignificant trends toward improved endocrine remission rates for patients with Cushing's disease (from 50% to 83%), but operative complications, notably the rates of hypopituitarism, did not change. Overall length of hospital stay decreased between time periods 1 and 2 (from 7 to 4 days median; P < .01). CONCLUSION: The improvements in the duration of surgery and visual outcome noted after about 50 endoscopic procedures would favor the existence of an operative learning curve for these parameters. This further highlights the benefits of subspecialization in pituitary surgery.