Extent of Resection, Visual and Endocrinological Outcomes for Endoscopic Endonasal Surgery for Recurrent Pituitary Adenomas

Object: The aim of this study is to the assess extent of tumor resection, complication rates, and visual and endocrinological outcomes after endoscopic endonasal surgery for recurrent or residual pituitary adenomas.

Methods: We retrospectively analyzed 61 patients that underwent endoscopic endonasal surgery for recurrent or residual pituitary adenomas from 2009–2016. All patients had previously undergone microscopic or endoscopic transsphenoidal procedures for pituitary adenomas.

Result: Most (80.3%) patients underwent one prior transsphenoidal operation, whereas the rest underwent two or more operations. The prior surgical approach was endoscopic endonasal in 55.7% and microscopic in 44.2% with equal proportion of transseptal and sublabial approaches. The mean preoperative maximal tumor diameter was 2.3 cm. Tumor commonly invaded the suprasellar cistern (63.9%) and the cavernous sinus (63.3%). Intraoperative cerebrospinal fluid (CSF) leak was encountered in 27 (44.2%) patients, but only 3 (4.9%) patients had a postoperative CSF leak. Gross total resection (GTR) was achieved in 31 (51.7%) patients overall. For Knosp grade 0–2 tumors, GTR was 68.4% and for Grade 3–4 tumors, it was 21.7% (p < 0.001). GTR was 73.1% for patients with previous microscopic transsphenoidal surgery and was 35.3% for patients with previous endoscopic endonasal surgery (p = 0.002). However, on multivariate analysis, only tumor size (p = 0.002) and cavernous sinus invasion (p < 0.001) were the only independent predictors for GTR. For patients with preoperative visual field deficits (n = 40), improvement occurred in 32.5% and no change in 62.5%. Visual deterioration occurred in 2 (5.0%) patients. New postoperative adrenal insufficiency, hypothyroidism, hypogonadism, and diabetes insipidus occurred in 6.5, 8.1, 6.5, and 4.9%, respectively. Rates of complications included meningitis (1.6%), medical complications (4.9%), postoperative hematoma (3.2%), and carotid artery injury/stroke (0%). Twelve (19.6%) patients required postoperative adjuvant radiotherapy for residual tumor.

Conclusion: We present the largest series of revision endoscopic endonasal operations for recurrent or residual pituitary adenoma after a prior transsphenoidal approach. Our study demonstrates that the endoscopic endonasal approach provides a safe and effective option for recurrent pituitary adenomas. Tumor size and cavernous sinus invasion were the primary determinants of extent of resection. Although patients with a prior microscopic approach had a significantly higher rate of GTR compared with those that had a prior endoscopic approach on univariate analysis, this was not statistically significant on multivariate analysis.