Pituitary surgery for the management of acromegaly

Active acromegaly is almost always the result of a benign growth hormone (G H)-secreting adenoma of the pituitary gland. Because the same pituitary ste m cell can produce both GH and prolactin (PRL), many acromegalic patients a lso have hyperprolactinemia. The advantages of surgical excision of pituita ry adenomas associated with acromegaly include: (1) prompt decrease in GH; (2) reliable and immediate relief of the mass effect from the tumor (decomp ression of the optic nerves and chiasm), and (3) the opportunity to obtain tumor tissue for characterization and investigative study. Currently, more than 97% of operations for removal of pituitary tumors associated with acro megaly are done using the transsphenoidal approach rather than craniotomy. Technical advances to make the surgery safer continue to evolve, and includ e endoscopic approaches, computer-guided image-based intraoperative visuali zation, and intraoperative magnetic resonance imaging. Criteria for satisfa ctory remission of acromegaly after surgery are the same as those used for medical management. They include normal insulin-like growth factor (IGF)-I and suppression of GH to undetectable levels (<1.0 ng/ml) during an oral gl ucose tolerance test (OGTT). Data from a recent series of 86 patients opera ted upon for acromegaly at the University of Virginia and followed for more than 1 year have been reviewed. In patients receiving surgery as the initi al procedure, 67% had a normal IGF-I, and 52% suppressed to <1.0 ng/ml in a n OGTT. There was one true recurrence of disease diagnosed 81 months after surgery. Results are best in patients with noninvasive mi croadenomas. Gamm a knife radiosurgery has been a valuable adjunct in those patients who fail to achieve postoperative remission. Pathological evaluation of the tumors revealed that 16% expressed GH only, 25% stained for GH and glycoprotein ho rmones (follicle stimulating hormone, thyroid hormone, thyroid stimulating hormone, a-subunit), 21% for GH and PRL, and 33% for GH, PRL and glycoprote in hormones. There was one acidophil stem cell tumor and 10% had the mammos omatotroph subtype. This contemporary series was free of mortality or serio us complications. One patient had a transient cerebrospinal fluid leak and 3 developed transient SIADH with hyponatremia. Surgical treatment remains a n important aspect of the combined management of patients with acromegaly. Copyright (C) 2000 S. Karger AG. Basel.