Endoscopic Transsphenoidal Pituitary Surgery: Evidence for an Operative Learning Curve

Objectives: The use of the fiberoptic endoscope has been a recent innovation in pituitary surgery. We investigated the evidence for an “operative learning curve” after the introduction of endoscopic transsphenoidal surgery at our unit.

Design: Retrospective study.

Methods: The first 125 patients who underwent endoscopic transnasal transsphenoidal surgery for pituitary fossa lesions between 2005 and 2007 by one surgeon were studied. Changes in a number of parameters were assessed between two 15-month time periods: Period 1, N = 53 patients, and Period 2; N = 72 patients.

Results: There were 67 (54%) patients with nonfunctioning adenomas (NFPA), 22 (18%) with acromegalies, and 10 (8%) with Cushing's disease. Between study periods 1 and 2, there was a decrease in the mean duration of surgery for NFPA (120 to 91mins; P < 0.01). This “learning effect” was not apparent for functioning adenomas, which also took longer to perform. The proportion of patients with an improvement in their preoperative VF deficits increased over the study period (80% to 93%; P < 0.05). There were nonsignificant trends toward improved endocrine remission rates for patients with Cushing's disease (50% to 83%), but operative complications, notably the rates of hypopituitarism, did not change. Overall length of hospital stay decreased between study periods 1 and 2 (7 to 4 days median; P < 0.01).

Conclusions: The improvements in the duration of surgery and visual outcome noted after approximately 50 endoscopic procedures would favor the existence of an “operative learning curve.” This further highlights the benefits of subspecialization in pituitary surgery.