Background: The postoperative exocrine pancreatic function was compared between pancreatoduodenectomy and distal pancreatectomy, and we studied the relationship between the preoperative morphology of the pancreas expected to remain and pancreatic function after surgery.

Patients and methods: In 27 patients who underwent pylorus-preserving pancreatoduodenectomy (PPPD group) and 12 who underwent distal pancreatectomy (DP group), the exocrine pancreatic function was assessed using the BT-PABA excretion test before surgery and short term after surgery (≤2 months). Preoperative morphology of the pancreas at a presumed line of transection was also investigated on computed tomography.

Results: The mean urinary PABA excretion rate in the PPPD group decreased from 68.3% to 53.7% (P = 0.0029), whereas that in the DP group showed no significant change (70.7% versus 72.7%). The mean size of the main pancreatic duct at the presumed transection line in the PPPD group was significantly greater than that in the DP group (6.5 mm versus 2.6 mm, P = 0.0002). The mean parenchymal thickness of the pancreatic gland at the presumed transection line in the PPPD group was significantly smaller than that in the DP group (16.1 mm versus 18.6 mm, P = 0.04). The mean ratio of the pancreatic duct caliber to parenchymal thickness (duct-parenchymal ratio) in the PPPD group was significantly higher than that in the DP group (0.43 versus 0.14, P = 0.0004). There was a significant negative correlation between the postoperative PABA excretion rate and the duct-parenchymal ratio (P = 0.0057).

Conclusions: The postoperative exocrine pancreatic function after PPPD and DP was significantly influenced by the morphology of the pancreas at the presumed transection line. It is important to evaluate the preoperative morphology of the presumably remaining pancreas, especially duct-parenchymal ratio, to predict the exocrine pancreatic function short term after pancreatectomy.