Three Types of Collateral Arterial Supply to the Spleen After Spleen-Preserving Distal Pancreatectomies with Splenic Vessel Resection—How to Use This Knowledge for Organ(s) Preservation in Locally Advanced and Borderline Resectable Pancreatic Head Ca

Background: Spleen-preserving (SP) distal pancreatectomy (DP) with splenic vessel resection (SVR) (Warsaw procedure, WP) is an option for the treatment of tumors with low malignant potential. The reverse blood flow through the short gastric arteries (SGA) explains the preservation of the spleen after SVR, but leaves the source of the blood supply to the SGAs hidden. The types of blood supply to the spleen after WP and their incidence have not been previously described, nor has the significance of these types for locally advanced pancreatic head cancer (LAPHC) surgery been determined. Aim: To determine the main types of spleen blood supply after WP, and to assess the feasibility and safety of splenic artery (SA) rotation for the organ-preserving surgery of LAPHC. Methods: Retrospective analyses of demographic and perioperative data, including CT scans, overall (OS) and progression-free (PFS) survival after 71 SP DP SVR and 41 SP SVR pancreaticoduodenectomies (PD) and total pancreatectomies (TP) for LAPHC (2007–2025). Results: In 134 SP procedures, SA was resected in 115 cases (71DP, 9 TP, 3 central, and 32 PD). Indications for surgery were MCN (41), IPMN (14), CSA (3), NEN (25), SPPN (8), PHDAC (40), sarcoma (1), autoimmune (1), and calculous chronic pancreatitis (1). There were no deaths or ischemia-related splenectomies. Morbidity—31% (n23); Dindo–Clavien (D-C) > 3b-2.8%; POPF-grade B-n7 (10.6%); splenic infarctions on CT after SVR-n18 (23%), one symptomatic. CT revealed three types of arterial blood supply to the spleen after SPDP SVR: left gastric artery (LGA) type (n50, 70, 5%), gastro-epyploic arcade (GEA) type (n9, 12, 5%), and an intermediate type (n12, 17%). Spleen- and pancreas tail-preserving SVR pancreatectomies for LAPHC (n41) were accompanied by rotation of the SA to substitute resected SMA (n19) and CHA (n15) for 26 Whipples and 8TPs. There were no ischemic complications. D-C > 3–19.5%. Median OS and PFS for PDAC were 35 and 21 months for 29.5 months median follow-up. Conclusions: Despite the preservation of blood flow through all potential sources of splenic blood supply following resection of the splenic artery, the main collaterals supplying the spleen after WP are LGA branches (~90%). This knowledge, with strict adherence to the developed criteria, allows for the safe preservation of the spleen, pancreatic tail, and stomach during pancreatectomies with SA resection, including its rotation for the substitution of the SMA and CHA in LAPHC.