Prevention of pancreatic fistula with a new synthetic, absorbable sealant: evaluation in a dog model

The Learning Curve for Pancreaticoduodenectomy: The Experience of a Single Surgeon

BACKGROUND AND AIMS

Pancreaticoduodenectomy (PD) is a complex and high-skill demanding procedure often associated with significant morbidity and mortality. However, the results have improved over the past two decades. However, there is a paucity of research concerning the learning curve for PD. Our aim was to report the outcomes of 100 consecutive PDs representing a single surgeon's learning curve and to depict the factors that influenced the learning process.

METHODS

We reviewed the first 121 PDs performed at our academic center (2013-2019) by a single surgeon; 110 were PDs (5 laparoscopic and 105 open) and 11 were total PDs (1 laparoscopic and 10 open). Subsequent statistics was performed on the first 100 PDs, with attention paid to the learning curve and survival rate at 5 years. The data were analyzed comparing the first 50 cases (Group 1) to the last 50 cases (Group 2).

RESULTS

The most frequent histopathological tumor type was pancreatic ductal adenocarcinoma (50%). A total of 39% of patients had preoperative biliary drainage and 45% presented with positive biliary cultures. The preferred reconstruction technique included pancreaticogastrostomy (99%), in situ hepaticojejunostomy (70%), and precolic gastro-jejunal anastomosis (88%). Postoperative complications included biliary fistula (1%), pancreatic fistula (8%), pancreatic stump bleeding (4%), and delayed gastric emptying (13%). The mean operative time decreased after the first 50 cases (p < 0.001) and blood loss after 60 cases (p = 0.046). R1 resections lowered after 25 cases (p = 0.025). Vascular resections (17%) did not influence the rate of complications (p = 0.8). The survival rate at 5 years for pancreatic adenocarcinoma was 32.93%.

CONCLUSIONS

Outcomes improve as surgeon experience increases, with proper training being the most important factor for minimizing the impact of the learning curve over the postoperative complications. Analyzing the learning curve from the perspective of a single surgeon is mandatory for accurate statistical results and interpretation.

A novel rat model for the study of postoperative pancreatic fistula

While over the past several decades mortality after pancreatic surgery has decreased to <5%, postoperative morbidity remains remarkably high, ranging from 15% to 65%. The development of a postoperative pancreatic fistula (POPF) is a significant contributor to morbidity in patients undergoing pancreatic surgery. POPF can lead to life-threatening conditions such as intra-abdominal abscess, uncontrolled hemorrhage, sepsis, and death. Rates of POPF have not significantly changed over time, despite the introduction of multiple technical and pharmacologic interventions aimed at their treatment and prevention. Unfortunately, there are few POPF experimental models that have been described in the literature and existing models are unable to reliably reproduce the clinical sequelae of POPF, limiting the development of new methods to prevent and treat POPF. Herein, we describe a new rat experimental model that reliably creates a POPF via transection of the common pancreatic duct.

A novel hydrogel sheet prevents postoperative pancreatic fistula in a rat model

Aim

To evaluate the efficacy of a novel hydrogel sheet in preventing postoperative pancreatic fistula (POPF).

Background

Postoperative pancreatic fistula is a life‐threatening complication. As no study has reported the use of hydrogel sheets in preventing POPF, their effectiveness for that purpose remains unclear.

Methods

A novel hydrogel sheet made of polyvinyl alcohol (PVA) was prepared by the freeze‐thaw method. The pancreatic ducts and surrounding pancreatic parenchyma of rats were transected to induce a pancreatic fistula. Next, the sheet was attached to the transection site. Ascitic fluid amylase and lipase concentrations were measured. Neoveil^®, a nonwoven polyglycolic acid (PGA) felt, is already clinically used as an absorbable reinforcing material at pancreatic transection sites. Neoveil^® was used for comparison, as was VIEWGEL^®, which is marketed as a wound dressing.

Results

The hydrogel sheet remained in place 48 hours postoperatively. The ascitic amylase concentrations in the control, VIEWGEL^®‐treated, Neoveil^®‐treated, and hydrogel‐treated rats, respectively, were 4992.4 ± 5355.7, 1068.4 ± 269.1, 730.2 ± 425.2, and 303.1 ± 240.1 IU/L; the ascitic lipase concentrations were 2279.8 ± 3395.2, 169.5 ± 100.6, 90.4 ± 71.0, and 86.8 ± 59.8 IU/L. The ascitic amylase and lipase levels were significantly lower in the hydrogel group than in the other groups (P < .05).

Conclusions

This novel hydrogel sheet effectively prevents pancreatic fistulas and has promising clinical application potential.

Development of a novel rat model with pancreatic fistula and the prevention of this complication using tissue-engineered myoblast sheets

BACKGROUND

Pancreatic fistula (PF) is one of the most important complications of pancreatic surgery. The aims of this study were to establish a PF model in rats and to investigate the efficacy of our new method for preventing PF, which utilizes myoblast sheets made using tissue engineering techniques.

METHODS

To establish a PF model, the rats underwent transection of each of four pancreatic ducts: the gastric, duodenal, common, and splenic ducts, respectively. Their ascitic amylase and lipase levels were then measured. To investigate the efficacy of myoblast sheets at preventing PF, a myoblast sheet was attached to the pancreatic stump in the PF models. The levels of amylase and lipase in both serum and ascites were then measured, and surgical specimens were investigated pathologically.

RESULTS

The new PF model established by transecting the splenic duct in rats may prove very useful. There were no significant differences in serum amylase and lipase levels between the myoblast sheet (+) group and the sheet (-) group. However, there were significant differences in ascitic amylase and lipase levels between the two groups (p < 0.05). Among the pathological findings, the number of inflammatory cells in the myoblast sheet group was smaller than that in the control group. In addition, the presence of the myoblast sheets on the surface of the pancreatic stump was confirmed by immunofluorescence staining.

CONCLUSION

Our data demonstrate the efficacy of the new rat model of PF presented herein, and that it might be possible to prevent PF using myoblast sheets.

Visualization of the leakage of pancreatic juice using a chymotrypsin-activated fluorescent probe

BACKGROUND

Pancreatic fistula (PF) remains the most serious complication after digestive surgery. It is difficult to prevent because of the inability to visualize the leakage of pancreatic juice during surgery or to evaluate the protease activity of leaked fluid, which is responsible for PF formation.

METHODS

The fluorescence intensities of a chymotrypsin probe (glutaryl-phenylalanine [corrected] hydroxymethyl rhodamine green with added trypsin) in pancreatic juice and in intestinal or abdominal fluids drained after pancreatic resection were evaluated. The chymotrypsin probe was sprayed on to filter papers that had been placed on the resected pancreatic stump in patients undergoing pancreaticoduodenectomy or central pancreatectomy. The ability of this technique to visualize the leakage of pancreatic juice and predict postoperative PF formation was assessed.

RESULTS

The fluorescence intensity of the chymotrypsin probe in 76 fluid samples correlated positively with amylase levels (r(s) = 0.678, P < 0.001). The fluorescence patterns of the pancreatic stump were classified grossly into the three types: duct (fluorescence signal visualized only on the stump of the main pancreatic duct, 16 patients), diffuse (ductal stump and surrounding pancreatic parenchyma, 7) and negative (no fluorescence signal, 7). Symptomatic PFs developed in 13 of 23 patients with duct- or diffuse-type fluorescence, but in none of the seven patients with negative-type fluorescence (P = 0.008).

CONCLUSION

The chymotrypsin probe enabled determination of the protease activity in drained pancreatic fluid samples and allowed real-time visualization of pancreatic juice leakage during surgery.

Animal models in pancreatic surgery: a plea for pork

There has been resurgence in the utilization of larger animal models in medicine over the last decade, particularly in the field of pancreatic research. With increasing pressures to more accurately replicate the human model prior to clinical application, an ideal animal model is necessary. Previous work in larger species (dog, pig) in pancreatic surgery research has identified several key anatomical differences that have led us to conclude that perhaps the swine is a model better fit for more accurate human representation.

Incidence of Postoperative Pancreatic Fistula and Hyperamylasemia after Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy

INTRODUCTION

The purpose of this study was to analyze the postoperative pancreatic morbidity of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of peritoneal surface malignancies (PSM).

PATIENTS AND METHODS

Two hundred and sixty five patients (87M/178F) with PSM underwent 270 consecutive procedures. The mean age was 52 years (range: 22-79 years). CRS was performed using peritonectomy procedures. HIPEC through the closed abdomen technique was conducted using cisplatin (CDDP 25 mg/m2/L of perfusate)+mitomycin C (MMC 3.3 mg/m2/L of perfusate) or CDDP (43 mg/L of perfusate)+doxorubicin (Dx 15.25 mg/L of perfusate), at 42.5 degrees C. Diagnosis and classification of postoperative pancreatic fistula (POPF) were performed according to the international study group on pancreatic fistula criteria. Serum amylase alterations were graded according to the National Cancer Institute (NCI) common terminology criteria for adverse events (CTCAE) v3.

RESULTS

POPF was observed in 13 (4.8%) cases. Three cases were classified as major (grade C). Two cases presented postoperative pancreatitis. G3-4 alteration of amylase was observed in 12.3% of the cases. Performing splenectomy and CDDP dosage for HIPEC >240 mg were proven to be independent risk factors for both G3-4 hyperamylasemia and POPF.

CONCLUSIONS

CRS+HIPEC presented an acceptable rate of pancreatic morbidity which did not contribute to the mortality related to the procedure. Most of the POPF were mild and/or easily controlled by conservative measures. Although not specific a normal amylasemia could be a useful marker of pancreatic integrity after CRS+HIPEC.