Transsphenoidal microsurgery for newly diagnosed acromegaly: a personal view after more than 1,000 operations

The aim of this short review is to inform about the possibilities and limits of transnasal microsurgery in acromegaly. The current reports on surgical remissions, according to the strict criteria with international consensus using age- and sex-related normal levels for insulin-like growth factor-I and suppression of growth hormone (GH) with oral glucose tolerance below 1 mug/l, are more or less agreeable with values between 34 and 74%. In microadenomas (<10 mm in diameter), 59-95% remissions are published. Some improvement might be achieved in macroadenomas which presently have a chance of 26-68% to be satisfactorily operated on. Special instruments introduced by us to visualize and remove partially invasive adenoma parts are described. Intraoperative magnetic resonance imaging is discussed. With intraoperative measurement of GH, small adenoma rests <3 mm can be diagnosed. When GH did not sufficiently decline, an additional tumor search resulted in a significant improvement in results in resectable macroadenomas. With these techniques, we achieved remission rates which can hardly be further increased (micros 95%, macros 68%). In grossly invasive grade 4 adenomas, which are frequent in our unit, only an 80-95% reduction in tumor mass is feasible. Preoperative treatment with somatostatin analogues as used in most of our patients reduces the comorbidity and facilitates adenoma removal which is still controversially discussed in the literature. The complication rate of microsurgery in experienced hands is low.