Predictors of visual and endocrine outcomes after endoscopic transsphenoidal surgery for pituitary adenomas

Surgery for pituitary adenoma is indicated for relief of mass effect and control of endocrinopathy. Setting benchmarks for visual and hormonal outcomes is important for monitoring performance of surgical centres, while understanding the preoperative factors that predict endocrine cure and visual improvement facilitates tailored counselling for patients prior to surgery. A prospective, consecutive cohort of surgically managed (endoscopic transsphenoidal) pituitary adenoma (n = 304) were analysed. Preoperative and postoperative endocrine and visual field assessments were performed and compared to demographic, imaging and pathological data. Larger adenomas tended to have preoperative endocrine deficiency (p < 0.001) and visual field defects (p < 0.001). The largest tumours did not experience normalisation of their endocrinopathy or visual fields with surgery. Of the adenomas with normal preoperative endocrine function, 92.0% (126/137) maintained this postoperatively; only 2 of the 11 patients with new hypopituitarism required long-term hormone replacement. Functional tumour cure was achieved in 65.2% (86/116) after surgery; 74.4% (32/43) of acromegalics and 70.0 (35/50) of Cushing's disease patients achieved hormonal control. All patients with isolated hyperprolactinaemia from stalk effect normalised with surgery, while only 15.9% (7/44) with hypopituitarism recovered normal endocrine function. New hypopituitarism was predicted by younger age and functional adenoma, particularly Cushing's disease. Resolution of endocrinopathy was less likely with reoperative cases and those with cavernous sinus invasion (Knosp grade > 2) or preoperative ophthalmoplegia. One-third of the cohort (102/304, 33.6%) had a preoperative field cut, most commonly an incomplete (51.0%) or complete (31.4%) bitemporal hemianopsia. Only two patients (2/304, 0.7%) had visual field worsening after surgery, while 71.6% (73/102) experienced partial or complete resolution of their field cut after surgery. Complete resolution of visual field defect was predicted by younger age and incomplete bitemporal hemianopsia. Surgery is a safe and effective therapy for pituitary adenomas. Nearly all patients experience improvement in visual fields, especially the young and those with incomplete bitemporal defects. Reoperative cases and those with cavernous sinus involvement (high Knosp grade/ophthalmoplegia) are less likely to have resolution of endocrinopathy. Visual worsening, new ophthalmoplegia or endocrinopathy were rare complications of surgery.