A total of 218 patients had undergone PD at Yamanashi University between January 2012 and December 2019. Among them, patients who were judged to have a hard pancreas based on intraoperative findings by a surgeon, or with a main pancreatic duct diameter of over 2 mm by magnetic resonance cholangiopancreatography (MRCP) were 98. Patients with a past history of pancreatitis were also included in this group.Of these, only 2 patients had POPF. Since they were considered to be a low risk group of POPF, we excluded them in this study.
The remaining 120 patients who were judged to have a soft pancreas based on intraoperative findings by surgeons, and patients with a main pancreatic duct diameter of 2 mm or less were selected. We divided them into two groups according to the PJ techniques. 53 patients underwent the modified technique (from April 2017 to December 2019; M group), and the remaining 67 patients underwent the conventional technique (from January 2012 to March 2017; C group). The clinical characteristics and pathological examinations were collected from electronic medical records. To supplement the perioperative data, we examined a review of the surgical and anesthetic charts of each patient. This study was approved by the Human Research Ethics Committee of Faculty of Medicine, University of Yamanashi (No. H30232).
For the patients with pancreatic cancer, we performed a subtotal stomach-preserving pancreatoduodenectomy. For the patients with other diseases, we performed a pylorus-preserving pancreatoduodenectomy. Portal vein and/or superior mesenteric vein resection was performed in combination with PD in patients with possible or definite tumor invasion. Reconstruction was performed according to the modified Child’s technique. After the jejunal limb was brought up through the antecolic route, we performed an end-to-side PJ first, followed by an end-to-side hepaticojejunostomy and end-to-side gastrojejunostomy. Two closed drainage tubes were routinely placed near the region where the PJ was being performed and at the underside of the hepaticojejunostomy. All the operations were performed by a hepato-pancreato-biliary team.
Conventional anastomosis for PJ
The outer layer of the end-to-side PJ was sutured in concentric circles centered on the duct-to-mucosa anastomosis. The anastomosis was constructed using 4-0 Vascufil (double-armed polybutester, Tyco Healthcare Co., USA).
1) First, a 5-Fr external stenting tube was inserted into the pancreatic duct through the anastomotic site of the jejunal wall. 2) The duct-to-mucosa anastomosis was performed in an end-to-side fashion with eight absorbable interrupted sutures using 5–0 PDS-II (Johnson and Johnson Co., Tokyo, Japan) and an external stent from the main pancreatic duct (Figure 1a). 3) Before the sutures of the duct-to-mucosa were tied, the needle of the 4-0 Vascufil was used to penetrate the pancreatic parenchyma from the cut surface of the pancreas to the posterior wall. The serous muscle layer of the jejunum was then penetrated in three small steps so as not to penetrate through all the layers of the wall. This was performed from the outside toward the insertion portion of the stent tube. The anastomosis of the posterior wall was performed at three places in total. 4) The anastomosis of both the upper and lower edges was performed. The needle of the 4-0 Vascufil penetrated through the pancreatic parenchyma from the wall of the pancreas to the cut surface near the duct-to-mucosa anastomosis. The serous muscle layer of the jejunum was then penetrated in three steps from near the insertion portion of the stent tube toward the outside (Figure 1b). 5) Then, all three sutures of the posterior wall threads were tied. Subsequently, the sutures of the duct-to-mucosa were tied. 6) Finally, the anastomosis of the anterior pancreatic wall was performed. The needle of the 4-0 Vascufil penetrated through the pancreatic parenchyma from the anterior wall of the pancreas to the cut surface near the duct-to-mucosa anastomosis. The serous muscle layer of the jejunum was then penetrated in three steps from near the insertion portion of the stent tube toward the outside. These procedures were performed at three places in total (Figure 1c).
Modified anastomosis: Triangular mattress suite method
We made changes to the anastomosis of the anterior pancreatic wall and both the upper and lower edges. The needle at the pancreatic side of the double-armed 4-0 Vascufil was sutured at a point 5 – 8 mm to the lateral side of the previous suture, which penetrated the jejunal seromuscular wall like a triangular mattress suite (Figure 1d). Then, all five sutures were tied gently to prevent the tearing of the pancreatic parenchyma. This procedure completely covered the needle holes of the pancreatic wall with the jejunal serosa (Figure 1e).
Prophylactic somatostatin analogs were not administered to prevent POPF. The amylase level in the drainage fluid (D-Amy) was routinely measured on postoperative days (PODs) 1 and 3. The drainage tube was removed on POD 3 if the drainage fluid was clear regardless of the amount of drainage fluid or D-Amy, indicating that no bacterial infection existed. POPF was diagnosed according to the International Study Group of Pancreatic Fistula criteria .
The following factors that may be associated with the formation of POPF were analyzed in this study: sex, age, BMI, white blood cell (WBC) count in peripheral blood, C-reactive protein (CRP), serum albumin, hemoglobin A1c (HbA1c), operative time, volume of blood loss, intraoperative blood transfusion, D-Amy and surgical procedures.
Data were expressed as the mean ± standard deviation. Patient characteristics and intraoperative and postoperative factors between the two groups were compared using Chi-square statistics, Fisher’s exact test and the Mann–Whitney U test. Significance was defined as a p-value <0.05. The statistical analyses were performed using SPSS version 23.0 software (SPSS Inc, Chicago, IL, USA).