Kimura’s vs Warshaw’s technique for spleen preserving distal pancreatectomy: a systematic review and metaanalysis of high-quality studies
Executive Summary
This briefing document synthesizes high-quality evidence comparing the two primary modalities for spleen-preserving distal pancreatectomy (SPDP): the Kimura technique (KT), which preserves the splenic vessels, and the Warshaw technique (WT), which involves the resection of these vessels.
Based on a systematic review and meta-analysis of 17 high-quality studies involving 1,999 patients, the following critical takeaways have been identified:
Superiority of Kimura Technique: The Kimura technique is significantly superior to the Warshaw technique in reducing the risk of splenic infarction and the development of gastric varices.
Primary Outcomes: Patients undergoing the Kimura procedure had a substantially lower risk of splenic infarction (OR = 0.14) and a lower risk of splenic infarction requiring subsequent splenectomy (OR = 0.29).
Secondary Outcomes: Splenic vessel preservation was associated with a reduced risk of gastric varices (OR = 0.1). While intraoperative blood loss and operative times were generally comparable, the Kimura technique showed a near-significant trend toward lower rates of grade B/C postoperative pancreatic fistula (POPF).
Clinical Recommendation: For benign pancreatic tumors and low-grade malignancies, the Kimura technique should be considered the preferred approach unless splenic vessel involvement is suspected.
Background and Surgical Context
Distal pancreatectomy (DP) is the standard treatment for lesions in the body and tail of the pancreas. While malignant lesions typically require concurrent splenectomy for adequate lymphadenectomy, spleen preservation is prioritized for benign or low-grade malignant tumors (e.g., neuroendocrine tumors, cystic neoplasms, and IPMNs).
Preserving the spleen is vital for maintaining immune function and avoiding middle-to-long-term complications such as Overwhelming Post-Splenectomy Infections (OPSI), abdominal abscesses, and various forms of thrombosis.
The Two Primary Techniques
Comparative Analysis of Clinical Outcomes
The systematic review analyzed data from 1,999 patients, the majority of whom (1,867) underwent minimally invasive surgery (laparoscopic or robotic).
Primary Endpoints: Splenic Health
The most significant differences between the two techniques involve organ perfusion and the risk of infarction.
Splenic Infarction: The Kimura technique demonstrates a significantly lower risk of infarction compared to the Warshaw technique. After sensitivity analysis to remove heterogeneity, the Odds Ratio (OR) was 0.14 (p < 0.0001).
Infarction Leading to Splenectomy: When splenic hypoperfusion occurs in the Warshaw group, it more frequently results in clinically relevant infarction. Kimura patients showed a significantly lower risk of requiring a rescue splenectomy (OR 0.29; p = 0.0003).
Secondary Endpoints: Complications and Recovery
While many perioperative variables showed no statistically significant difference, specific trends emerged:
Gastric Varices: Preservation of the splenic vessels significantly limits the development of portal hypertension. The risk of gastric varices was substantially lower in the Kimura group (OR = 0.1; p < 0.0001).
Postoperative Pancreatic Fistula (POPF): Kimura patients exhibited a lower risk of grade B/C POPF (OR = 0.76), though this reached only near-significance (p = 0.08).
Blood Loss and Operative Time: Meta-analysis failed to identify significant differences in these areas. While some surgeons claim the Warshaw technique is faster, the evidence suggests that once sensitivity analysis is applied, operative times and blood loss are comparable between high-quality studies.
Hospital Stay: There was a slight trend toward reduced length of hospitalization for Kimura patients, though it was not statistically significant.
Summary of Meta-Analysis Findings
Methodological Quality and Risk of Bias
The analysis was restricted to "high-quality" studies, defined as those with a Newcastle–Ottawa Scale (NOS) score of ≥ 7.
Study Design: All 17 included studies were retrospective cohort studies.
Bias Assessment: The largest risk of bias was found in "deviations from intended interventions," which is common in surgical literature where intraoperative findings may force a change in technique (crossover).
Metaregression: Analysis was conducted to see if variables like year of publication, sample size, or surgeon experience (proxied by journal H-index) influenced outcomes. No independent predictors were found for splenic infarction, blood loss, or operative time, suggesting these outcomes are inherent to the techniques themselves rather than external factors.
Conclusion
The Kimura technique for splenic vessel-preserving distal pancreatectomy is superior to the Warshaw technique in terms of preserving splenic perfusion and preventing long-term complications like gastric varices. Although the Kimura technique is more technically demanding due to the need to dissect the pancreas from the splenic vein, it results in a significantly lower incidence of splenic infarction and subsequent rescue splenectomy.
For patients with benign or low-grade malignant tumors of the pancreatic body and tail, the Kimura technique should be the first-choice surgical modality. The Warshaw technique remains a viable alternative when splenic vessel involvement is suspected or when vessel preservation is not technically feasible.
