Key Causes and Temporal Window of Unplanned Readmissions Following Transsphenoidal Pituitary Surgery: A Systematic Review and Meta-Analysis

Objective: Unplanned readmission (UR) after transsphenoidal pituitary surgery poses a significant healthcare burden, but its exact incidence, causes, and risk factors remain unclear. This meta-analysis aims to estimate the 30-day UR rate, identify its main causes, and explore associated risk factors. Methods: A systematic search of PubMed, Embase, Scopus, and Web of Science was conducted from inception to July 2025. Included studies reported 30-day UR rates and risk factors after transsphenoidal pituitary adenoma resection. Pooled incidence rates and odds ratios (ORs) with 95% confidence intervals (CIs) were derived using random-effects models. Heterogeneity was evaluated with I² statistics, and study quality was assessed using the Newcastle-Ottawa Scale. Results: Ten studies with 51,618 patients were included. The pooled 30-day UR rate was 9.68% (95% CI: 7.87–11.91). Hyponatremia (28.67%, 95% CI: 15.30–53.72) and cerebrospinal fluid leak (15.7%, 95% CI: 8.07–30.53) were the most common causes. Both all-cause and hyponatremia-related readmissions clustered early after surgery, with mean times of 9.96 days (95% CI: 6.51–13.42) and 8.05 days (95% CI: 5.86–10.25), respectively, suggesting a shared high-risk window around the first two weeks. No risk factor was reported in more than two studies, preventing meta-analysis of predictors. Conclusion: This meta-analysis confirms a high 30-day UR rate (nearly 10%) after transsphenoidal pituitary surgery, primarily due to hyponatremia and CSF leak. The aligned timing of readmissions underscores a critical post-discharge period. These findings emphasize the need for structured follow-up and early intervention—especially extended electrolyte monitoring and complication-specific management—to effectively reduce readmission risk.