Why Does Postoperative Pancreatic Fistula Occur After Hand-sewn Parenchymal Closure and Staple Closure in Distal Pancreatectomy?

Abstract

Hand-sewing (HS) and stapling are common parenchymal closure techniques after distal pancreatectomy. However, these methods cannot completely prevent postoperative pancreatic fistula (POPF). The mechanisms of POPF formation after closure are unknown. We performed distal pancreatectomy in mongrel dogs to identify the mechanisms of POPF formation after HS and staple closure. We measured the closed pancreatic duct burst pressures and examined the histology of the remnant pancreas. The after stapleclosure burst pressures depended on stapler height; lower pressures were associated with greater stapler heights. Post-HS closure burst pressures were significantly higher than those at each stapler height (P < 0.01). Post-HS closure pathologic findings showed extensive necrosis (day 3), and some regenerated pancreatic duct stumps (day 5). Necrosis was not observed around the stapled tissues. Although HS completely closes the pancreatic ducts, stump necrosis and blood flow disturbances may cause POPF. With stapler closure, pancreatic fluid leakage may occur even with appropriate stapler heights.

Results of Standard Stapler Closure of Pancreatic Remnant After Distal Spleno-Pancreatectomy for Adenocarcinoma

“…A higher extension of tissue necrosis with hand-sewn suture compared with stapler suture has been experimentally observed at a pathology examination in the pancreatic stump of mongrel dogs (12). Normal pancreatic parenchyma is soft and fragile (35), and a tight hand-sewn ligation may reduce blood flow to the pancreatic stump, thus leading to ischemia, necrosis, and development of POPF (12). Blood flow discrepancies may alter the proportion between regenerated pancreatic ducts under tension and granulation tissue with fluid from regenerated ducts flowing through the necrotic tissue.…”

“…Hand-sewn stump closure may induce a higher burst of pressure and more blood flow disturbances with tissue necrosis than staple closure. A higher extension of tissue necrosis with hand-sewn suture compared with stapler suture has been experimentally observed at a pathology examination in the pancreatic stump of mongrel dogs (12). Normal pancreatic parenchyma is soft and fragile (35), and a tight hand-sewn ligation may reduce blood flow to the pancreatic stump, thus leading to ischemia, necrosis, and development of POPF (12).…”

“…Stapler closure of the pancreatic stump may be supported by some experimental evidence based on the physiopathology of the pancreatic fistula (12). POPF is caused by leakage from regenerated pancreatic duct branches, whenever flow disturbances evolving toward necrosis occur over the cut surface of the pancreas.…”

“…The incidence of postoperative pancreatic fistula (POPF) after distal pancreatectomy varies from 10 to 40% (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). POPF is caused by leakage from the pancreatic duct branches that connect the main pancreatic duct with the cut surface (12). Although results of pancreatic surgery significantly improved in the last decades, the incidence of POPF has not significantly decreased, and it remains a cause of significant postoperative morbidity (13) as it may be followed by complications leading to re-operation (14), prolonged hospital stay, and increased costs (15).…”

“…Such variability in results and rate of fistula formation may be related both to technical factors and to patient-related variables, including American Society of Anesthesiologists (ASA) score, body mass index (BMI)/overweight, diabetes, hypoalbuminemia, pancreatic thickness, indication for operation (invasive ductal carcinoma, pancreatitis, neuroendocrine tumors), level of pancreatic transection, length, and complexity of operation, associated splenectomy, and intra-operative bleeding (12,(23)(24)(25)(26).…”