Association between pituitary adenoma consistency, resection techniques, and patient outcomes: a single-institution experience

OBJECTIVE The present study aimed to investigate the association between pituitary adenoma (PA) consistency and other measurable tumor characteristics, extent of resection (EOR), postoperative complications, and outcomes. METHODS In total, 507 PA resections were intraoperatively assigned a consistency grade from 1 (cystic/hemorrhagic tumors) to 5 (calcified tumors) based on intraoperative tumor characteristics. Tumor consistency was analyzed in tertiles (grades 1 and 2, grade 3, and grades 4 and 5) to determine associations with tumor characteristics, EOR, recurrence, postoperative outcomes, and complications. RESULTS The cohort in this study included primarily macroadenomas (93.3%) comprised mostly of nonfunctional PAs (NFPAs) (79.5%), with 77.1% showing suprasellar extension, 16.6% showing infrasellar invasion, and 46.4% showing cavernous sinus invasion (CSI). PA consistency grades were as follows: grade 1 or 2 (40.6%), grade 3 (39.3%), and grade 4 or 5 (20.1%). Compared with grade 1 or 2, higher-consistency PAs were more common in men (p = 0.001) and trended toward lower rates of gross-total resection (GTR) (67.6% vs 53.5%, p = 0.06). Higher PA consistency was predictive of any postoperative complication (OR 1.23, 95% CI 1.05–1.43; p = 0.009), specifically including transient diabetes insipidus (DI) (OR 1.45, 95% CI 1.12–1.85; p = 0.004) and cranial nerve (CN) paresis (OR 3.45, 95% CI 1.56–7.69; p = 0.002). Higher consistency was a strong predictor of CN palsy (OR 3.33, 95% CI 1.52–7.30; p = 0.004) for NFPAs. Higher-consistency PAs were more frequently adrenocorticotropic hormone–positive in both univariable (OR 1.33, 95% CI 1.11–1.60; p = 0.002) and multivariable (OR 1.38, 95% CI 1.11–1.69; p = 0.004) analyses. Higher consistency was associated with lower rates of GTR on stratification by CSI for Knosp grade 3 (p < 0.001) and grade 4 (p < 0.001) PAs, but not in low-grade (Knosp grades 1 and 2) PAs. CONCLUSIONS Tumor consistency is an important consideration for the resection strategy, particularly for PAs with CSI, and a predictor of intraoperative CSF leaks and perioperative complications and outcomes, including EOR, CN paresis, and transient DI.