Endoscopic transsphenoidal pituitary surgery: a single surgeon experience and the learning curve

Endoscopic transsphenoidal surgery for pituitary adenomas has been introduced as an alternative to transsphenoidal microsurgery. This is the first Australian study to evaluate a single surgeon's experience by comparing our results with other series and attempting to identify a learning curve. Retrospective analysis was carried out on 79 consecutively treated patients by fully endoscopic transsphenoidal surgery by a single neurosurgeon over a period spanning from July 1998 to September 2010 at St George Public and Private hospitals. The mean age at time of surgery was 56.7 years (SD +/- 16.3, range 26-85) and the mean follow-up period was 38.2 months (SD +/- 33, range 1-136). Gross total resection (GTR) was noted in 63% of patients, endocrinological cure was achieved in 53% and visual field improvements were noted in 86% of patients. Intra-operative CSF leaks occurred in 19% of procedures, while the rates of post-operative CSF rhinorrhea was 3% and post-operative diabetes insipidus was 13%. There was one post-operative death (1%). Compared to microsurgery, intra-operative CSF leaks and meningitis seem less frequent with an endoscopic approach. With increasing experience, we found a non-statistically significant trend towards higher rates of GTR, and improved visual fields. Endocrinological cure rates were clearly better with experience (p < 0.01). There may be a learning curve that can be overcome in 30-40 cases. Endoscopic transsphenoidal surgery provides similar tumour and patient outcomes when compared to transsphenoidal microsurgery. In this single surgeon's experience, there was a trend to indicate improved performance with more case experience.