Prediction of postoperative pancreatic fistula and pancreatitis after pancreatoduodenectomy or distal pancreatectomy: A review

BACKGROUND AND OBJECTIVE

Postoperative pancreatic fistula (POPF) is the leading cause of morbidity and early mortality in patients undergoing pancreatic resection. In addition, recent studies have identified postoperative acute pancreatitis (POAP) as an independent contributor to morbidity. Most perioperative mitigation strategies experimented for POPF have been shown to be in vain with no consensus on the best perioperative management. Clinical prediction models have been developed with the hope of identifying high POPF risk patients with the leading idea of finding subpopulations possibly benefiting from pre-existing or novel mitigation strategies. The aim of this review was to map out the existing prediction modeling studies to better understand the current stage of POPF prediction modeling, and the methodology behind them.

METHODS

A narrative review of the existing POPF prediction model studies was performed. Studies published before September 2022 were included.

RESULTS

While the number of POPF prediction models for pancreatoduodenectomy has increased, none of the currently existing models stand out from the crowd. For distal pancreatectomy, two unique POPF prediction models exist, but due to their freshness, no further external validation or adoption in clinics or research has been reported. There seems to be a lack of adherence to correct methodology or reporting guidelines in most of the studies, which has rendered external validity-if assessed-low. Few of the most recent studies have demonstrated preoperative assessment of pancreatic aspects from computed tomography (CT) scans to provide relatively strong predictors of POPF.

CONCLUSIONS

Main goal for the future would be to reach a consensus on the most important POPF predictors and prediction model. At their current state, few models have demonstrated adequate transportability and generalizability to be up to the task. Better understanding of POPF pathophysiology and the possible driving force of acute inflammation and POAP might be required before such a prediction model can be accessed.

[Pancreaticoduodenectomy - results and prospects (two-center study)]

OBJECTIVE

To summarize the results of pancreaticoduodenectomy (PD) for pancreatic tumors and complications of chronic pancreatitis regarding prediction and prevention of postoperative complications.

MATERIAL AND METHODS

There were 336 PD procedures between 2016 and mid-2022 in two centers. We assessed the factors influencing specific postoperative complications (postoperative pancreatitis, pancreatic fistula, gastric stasis, arrosive bleeding). Several risk factors were distinguished: baseline pancreatic disease and tumor size, CT-signs of a «soft» gland, intraoperative assessment of the pancreas, number of functioning acinar structures. We assessed surgical prevention of pancreatic fistula via preserving adequate blood supply to the pancreatic stump. The last one is provided by extended pancreatic resection and reconstructive stage of surgery, i.e. Roux-en-Y hepatico- and duodenojejunostomy with isolation of pancreaticojejunostomy on the second loop.

RESULTS

Postoperative pancreatitis underlies specific complications after PD. The risk of pancreatic fistula in case of postoperative pancreatitis increases by 5.3 times compared to patients without pancreatitis. Postoperative pancreatic fistula is more common in patients with T1 and T2 tumors. According to univariate analysis, only pancreatic fistula significantly affects the risk of gastric stasis. Among 336 people who underwent PD, pancreatic fistula occurred in 69 patients (20.5%), gastric stasis - in 61 (18.2%), pancreatic fistula complicated by arrosive bleeding - in 45 (13.4%) patients. Mortality rate was 3.6% (n=15).

CONCLUSION

Modern prognostic criteria are valuable to predict specific complications after PD. A promising way to prevent postoperative pancreatitis can be extended pancreatic resection considering angioarchitectonics of the pancreatic stump. Roux-en-Y pancreaticojejunostomy is advisable to reduce aggressiveness of pancreatic fistula.

[Postoperative pancreatitis after pancreatoduodenectomy]

OBJECTIVE

Retrospective assessment of the influence of postoperative pancreatitis in development of pancreatic fistula.

MATERIAL AND METHODS

The study included 173 patients after pancreatoduodenectomy performed between 2016 and 2019. Postoperative pancreatitis within the 1^st postoperative day was verified considering blood amylase > 125 U/L. Patients with postoperative pancreatitis (n=36) were included in the main group, the control group consisted of 137 patients without pancreatitis. Postoperative pancreatic fistula was determined according to the ISGPS 2016 classification. Statistical analysis of the effect of postoperative pancreatitis on development of pancreatic fistula was carried out using relative risk and odds ratio with 95% confidence interval in both groups.

RESULTS

Postoperative pancreatitis occurred in 36 (20.8%) out of 173 patients after pancreatoduodenectomy. Pancreatic fistula occurred in 18 (50%) cases. Among 137 patients without postoperative pancreatitis, only 18 (13.1%) patients developed severe pancreatic fistula. Relative risk was 3.8 (95% CI 2.22-6.51, p<0.0001), odds ratio - 6.6 (95% CI 2.91-15.01, p<0.0001).

CONCLUSION

Postoperative pancreatitis significantly influences development of severe pancreatic fistula.

Postoperative pancreatic fistula: a review of traditional and emerging concepts

Postoperative pancreatic fistula (POPF) remains the major cause of morbidity after pancreatic resection, affecting up to 41% of cases. With the recent development of a consensus definition of POPF, there has been a large number of reports examining various risk factors, prediction models, and mitigation strategies for this costly complication. Despite these strategies, the rates of POPF have not significantly diminished. Here, we review the literature and evidence regarding both traditional and emerging concepts in POPF prediction, prevention, and management. In particular, we review the evidence for the association between postoperative pancreatitis and POPF, and present a novel proposed mechanism for the development of POPF.