Endoscopic Endonasal Approach to the Growth Hormone-Secreting Pituitary Adenomas: Endocrinologic Outcome in 68 Patients

BACKGROUND: The endoscopic endonasal approach has recently become an acceptable option for resection of all pituitary adenomas. We assessed biochemical outcome of endoscopic endonasal surgery in growth hormone (GH)-secreting adenomas, including remission rate, predictors of remission, and associated complications. METHODS: Sixty-eight consecutive patients with acromegaly who underwent endoscopic endonasal surgery were analyzed prospectively. Tumors were classified according to size, Knosp grade, and Hardy-Wilson classification. Biochemical remission was defined as normal serum insulin-like growth factor 1 level and either a suppressed GH serum level less than 0.4 mu g/L during an oral glucose tolerance test or a random GH level less than 1.0 mu g/L at least 3 months after surgery. RESULTS: Total biochemical remission rate was 64.7%. Gross total resection was achieved in 61 of the 68 patients (89.7%). Remission was achieved in 12 of 16 microadenomas (75%) and 32 of 52 macroadenomas (61.5%). Based on univariate logistic regression analysis, preoperative variables predictive of remission were age (P = 0.004), Knosp grade (P = 0.023), and preoperative GH levels (P = 0.042). Three patients (4.4%) experienced postoperative panhypopituitarism, and permanent diabetes insipidus was seen in 4 patients (5.9%). Two patients (2.9%) developed cerebrospinal fluid leaks, which were treated by lumbar puncture in one case and early surgical repair in the other case. CONCLUSIONS: Endoscopic endonasal adenoma resection leads to a high rate of endocrinologic remission in GH-secreting adenomas with a low complication rate. Patients with older age, higher preoperative GH levels, and higher Knosp grades are less likely to achieve remission.