Cavernous Sinus Invasion in Pituitary Adenomas: Systematic Review and Pooled Data Meta-Analysis of Radiologic Criteria and Comparison of Endoscopic and Microscopic Surgery

Background: Despite the substantial impact of cavernous sinus invasion (CSI) in pituitary adenoma surgery, its radiologic determination has been inconsistent and variable, and the role of endonasal endoscopic surgery has been unclear. This is a systematic review and pooled data meta-analysis of the literature to ascertain the best radiologic criteria for CSI and verify the efficacy and safety of an endonasal endoscopic approach.

Methods: We searched the MEDLINE database (1993-2015) to identify studies on radiologic criteria for CSI and endonasal surgery. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the studies included were reviewed for CSI criteria, gross total resection (GTR), endocrine remission, cranial nerve deficits, carotid injury, and other complications.

Results: The prevalence of CSI was 43% radiographically compared with 18% intraoperatively (P < 0.001). The radiologic criteria of inferolateral venous compartment obliteration and Knosp 3-4 had the highest correlation with intraoperative CSI and the lowest correlation with GTR. Microscopy had significantly overestimated intraoperative CSI compared with endoscopy (P < 0.001) for each Knosp grade. Endoscopy had significantly higher GTR than did microscopy particularly for Knosp 3-4 (47% vs. 21%; P = 0.001). Carotid injury and cranial nerve deficits occurred in 0.9% and 5%, respectively, with endoscopy. Among endoscopic series with CSI, GTR% showed significant correlation with number of patients in the series (P ≤ 0.01) but no correlation with complications, indicating the relative safety of endonasal endoscopy in experienced hands for removing tumors with CSI.

Conclusions: Knosp 3-4 remains the best objective indicator of CSI. Microscopy tends to overestimate intraoperative CSI compared with endoscopy. Among pituitary adenomas with CSI, GTR in endoscopic series is higher than microscopy and improves with experience without significant additional morbidity.