IRB 00006477.

We conducted the reported risk stratification study for PD using a nationwide surgical database. PD outcomes in the national population were satisfactory, and the risk model could help improve surgical practice quality.

Perineural invasion is an important prognostic factor in pancreatic cancer, increasing as the cancer becomes undifferentiated. Even if there are no cancer cells at the margin of the pancreas at the time of surgery, the cancer cells may spread further to the noncancerous pancreas or retroperitoneum. Sufficient dissection of the neural plexus or intraoperative radiation may be required.

Background Preservation of the spleen in distal pancreatectomy has recently attracted considerable attention. Since our first trial and success with spleen-preserving distal pancreatectomy with conservation of the splenic artery and vein for tumors of the pancreas and chronic pancreatitis, this procedure (Kimura's procedure) has been performed very frequently. Methods The techniques for spleen-preserving distal pancreatectomy (SpDP) with conservation of the splenic artery and vein are clarified. The splenic vein is identified behind the pancreas and within the thin connective tissue membrane (fusion fascia of Toldt). The connective tissue membrane is cut longitudinally above the splenic vein. It is important to remove the splenic vein from the pancreas by working from the body of the pancreas toward the spleen (median approach), because it is very difficult to remove it in the other direction. The pancreas is removed from the splenic artery by proceeding from the spleen toward the head of the pancreas. Results Preservation of the spleen offers various advantages. The maximum platelet levels in blood serum are significantly lower in postoperative patients with splenic preservation than in those with splenectomy. The platelet count was maximal on postoperative day 10 in the 16 patients with SpDP and the count was maximal on postoperative day 13 in the 16 patients with distal pancreatectomy with splenectomy (DPS), and there was a smaller increase in the patients with SpDP than in the patients with DPS. Postoperative bleeding from an ablated splenic artery and vein in SpDP has not been encountered. Either DPS or spleen preservation without preservation of the splenic artery and vein may reduce the blood supply to the residual proximal stomach after distal gastrectomy, which is different from the findings in the Kimura procedure. Conclusion In SpDP, a very slight elevation of the platelet count in serum may help to prevent infarction of the lungs and brain compared to DPS. Another advantage of SpDP performed according to our procedure is that the blood supply to the proximal stomach is conserved in patients with SpDP who undergo distal gastrectomy with resection of the left gastric artery. Benign lesions, as well as low-grade malignancy of the body and tail of the pancreas, may be indications for this procedure. Surgeons should know the techniques and significance of SpDP with conservation of the splenic artery and vein, which is a very safe and reliable method.