Comparative Outcomes of Kimura vs. Warshaw Techniques in Spleen-Preserving Distal Pancreatectomy: A Systematic Review and Meta-Analysis

Purpose: The purpose of this research is to synthesize and evaluate the available comparative evidence on two principal surgical techniques for spleen-preserving distal pancreatectomy (SPDP): the Kimura technique (splenic vessel preservation) and the Warshaw technique (splenic vessel ligation). While SPDP is the standard of care for benign and low-grade malignant pancreatic tumors, uncertainty remains regarding which technique offers superior patient outcomes. Individual studies are often limited by sample size and design. This project aims to resolve clinical equipoise by providing a high-quality, quantitative synthesis of evidence to guide surgical decision-making and improve patient care. Methods: This study is a systematic review and meta-analysis conducted in accordance with the PRISMA 2020 and MOOSE guidelines. A comprehensive search was performed across multiple electronic databases (PubMed/MEDLINE, Embase, Cochrane Library, Scopus, CNKI) from inception to March 2025. Comparative studies (randomized controlled trials, cohort studies) directly comparing the Kimura and Warshaw techniques for SPDP were included. Two independent reviewers conducted study selection, data extraction, and risk of bias assessment using the Newcastle-Ottawa Scale (NOS) and ROBINS-I tool. The primary outcome is the incidence of splenic infarction. Secondary outcomes include postoperative pancreatic fistula, gastric varices, splenectomy rates, operative time, blood loss, and hospital length of stay. Statistical synthesis was performed using Review Manager 5.4, employing random- or fixed-effects models as appropriate. Heterogeneity was assessed using the I² statistic, and sensitivity/subgroup analyses were planned to explore robustness and sources of variation. Expected Outcomes: We anticipate that this meta-analysis will provide clear, evidence-based conclusions regarding the comparative safety and efficacy of the two techniques. Specifically, we expect the findings to demonstrate that the Kimura technique is associated with a significantly lower risk of splenic infarction, gastric varices, and clinically relevant postoperative pancreatic fistula, without meaningfully increasing operative time or blood loss. The results are expected to support the Kimura technique as the preferred approach when technically feasible, while affirming the Warshaw technique as a vital alternative in complex cases. The project will yield a manuscript for submission to a peer-reviewed surgical journal, with the goal of informing clinical practice guidelines and shaping future research directions in minimally invasive pancreatic surgery. Significance: This work addresses a persistent gap in surgical evidence that directly impacts patient outcomes. By clarifying which technique optimizes spleen preservation and minimizes complications, this review has the potential to reduce postoperative morbidity, improve long-term patient quality of life, and offer evidence-based guidance to surgeons worldwide. The project emphasizes methodological rigor, transparency, and open science principles, with all search strategies, data, and analytical code available to support reproducibility and further inquiry. Keywords: Spleen-preserving distal pancreatectomy, Kimura technique, Warshaw technique, splenic vessel preservation, meta-analysis, pancreatic surgery, postoperative outcomes, minimally invasive surgery.