Small Duct Size Research Articles

Predictors of post-operative pancreatic fistula formation in pancreatic neuroendocrine tumors: A national surgical quality improvement program analysis

BackgroundPost-operative pancreatic fistula (POPF) is a serious complication following pancreas surgery. We aimed to establish factors associated with POPF specifically in patients with pancreatic neuroendocrine tumors (PNET). MethodsThe 2014–2018 American College of Surgeons National Surgical Quality Improvement Program database was querried for patients undergoing resection for PNET. The impact of patient, tumor, and operative factors on POPF formation was evaluated. Results3532 patient underwent resections for PNET. The POPF rate was significantly higher in patients with PNET (24.8%) versus non-PNET (16.4%) (p < 0.0001). Male sex (OR 1.45, 95% CI 1.11–1.89), enucleation (OR 3.14, 95% CI 1.10–8.98), pancreaticoduodenectomy (OR 1.51, 95% CI 1.13–2.03), small duct size <3 mm (OR 3.24, 95% CI 1.62–6.48), and soft gland texture (OR 1.81, 95% CI 1.18–2.77) were independently associated with POPF in PNET patients on multivariable analysis. ConclusionsPOPF is more common in patients undergoing resection for PNET and is dictated primarily by surgical approach and gland characteristics.

External validation of four Pancreatic Fistula Risk Score models in the Deep South US: Do racial disparities affect pancreatic fistula prediction?

BackgroundFistula Risk Score (FRS) models often lack adequate discrimination for clinically relevant postoperative pancreatic fistula (CR-POPF) on external validation. We tested four FRS models in the Deep South United States and sought to determine if CR-POPF discrimination was affected by racial disparities. MethodsA single-institution retrospective cohort study of patients who underwent pancreatoduodenectomies between 2013 and 2019 was performed. FRS discrimination for CR-POPF was assessed using ROC curves for both the entire patient population, and for Black vs White patients. ResultsThe Alternative FRS maintains adequate CR-POPF discrimination when considering the patient population as a whole, but inadequately predicts CR-POPF when applied to the Black patient population. The Sun-FRS provides adequate CR-POPF discrimination for Black patients when considering risk grade. Only soft pancreatic gland texture and small duct size were significantly associated with CR-POPF in this patient population. DiscussionInstitutions should assess their preferred FRS model to determine if it provides adequate CR-POPF discrimination among a racially diverse patient population. Further studies are needed to determine how racial disparities influence CR-POPF prediction to better guide postoperative management.

Video review reveals technical factors predictive of biliary stricture and cholangitis after robotic pancreaticoduodenectomy

BackgroundCholangitis due to anastomotic stricture of the hepaticojejunostomy (HJ) following pancreaticoduodenectomy (PD), while uncommon, adversely affects postoperative quality-of-life. While prior studies have identified patient-related risk factors for these biliary complications, technical risk factors have not been systematically examined. Video review of surgical procedures has helped define technical details predictive of postoperative complications in bariatric and hepato-pancreato-biliary (HPB) surgery. Similarly, the present study utilized video review to identify technical factors associated with cholangitis and anastomotic biliary stricture following robotic PD. MethodsThis was an observational study. A blinded experienced HPB surgeon reviewed videos of post-learning-curve HJs performed during robotic PD and extracted 20 technical variables. Other demographic and clinical variables were collected from a prospectively maintained database. Results241 robotic PD videos were reviewed. 29 (12.0%) developed cholangitis and/or biliary stricture, with a median time-to-event of 189 (IQR 78–365) days. Several clinical and technical factors were independently predictive of cholangitis and/or biliary stricture: preoperative radiotherapy, small duct size (<10 mm diameter), increased distance of the HJ (>10 mm) from the hilar plate, and continuous suturing technique. ConclusionPost-hoc video review of HJ is a powerful method to predict biliary complications. Moreover, altering specific technical factors might enable surgeons to improve postoperative outcomes.

Postoperative pancreatic fistula after pancreatic resection.

The failure of pancreatic anastomosis after the proximal pancreaticoduodenectomy (PD) and the failure of pancreatic stump after the distal pancreatectomy with a resulting postoperative pancreatic fistula remain the most feared complications after pancreatic resection. Surgeons have been trying to find a reliable reconstructive technique of pancreatic anastomosis for decades. A literature search was performed to January 2020. Studies giving a detailed description of the pancreatic anastomosis after open PD and pancreatic stump closure techniques after the distal pancreatectomy were included. The aim of this study was review reported data derived from meta-analyses concerning the incidence of POPF according to the International Study Group of Pancreatic Surgery. A comparison of various surgical techniques and their impact on POPF incidence was made. In the group of clinically relevant POPF (CR- POPF), a well established difference between the patients undergoing POPF-associated interventional drainage or reoperation was observed. Meta-analyses showed that the patients with CR- POPF were statistically more likely to have a small duct size, soft gland texture, particular pancreatic neoplasms and an excessive intraoperative blood loss. Grade C POPF following PD, although uncommon, occurs with a defined incidence and is associated with a substantial morbidity, prolonged hospitalization, delayed recovery and a significant mortality. According to the results of various meta-analyses, pancreatogastrostomy and pancreatojejunostomy seemed to be comparable anastomotic techniques following PD (Ref. 54).

Pasireotide does not prevent postoperative pancreatic fistula: a prospective study

BackgroundPancreatic fistula is a major cause of morbidity after pancreas surgery. In 2014, a single-center, randomized-controlled trial found pasireotide decreased pancreatic fistula rates. However, this finding has not been validated, nor has pasireotide been widely adopted. MethodsA single-arm study in 111 consecutive patients undergoing pancreatic resection April 2015–October 2016 was conducted. Beginning immediately before surgery, patients received 900 μg subcutaneous pasireotide twice daily for up to seven days. Fistula rates were compared to 168 historical controls from July 2013 to March 2015. The primary outcome was Grade B/C fistula, as defined by the International Study Group on Pancreatic Fistula (ISGPF). ResultsThere were no significant differences between the pasireotide group and historical controls in demographics, comorbidities, operation type, malignancy, gland texture, or pancreatic duct size. Pasireotide did not reduce fistula rate (15.5% control versus 17.1% pasireotide, p = 0.72). In subgroup analyses of pancreaticoduodenectomy or distal pancreatectomy, or patients with soft gland texture and/or small duct size, there was no decrease in fistulas. Thirty-nine patients (38%) experienced dose-limiting nausea. ConclusionsIn an appropriately-powered, single-institution prospective study, pasireotide was not validated as a preventive measure for pancreatic fistula.

Analytical considerations of local thermal non-equilibrium conditions for thermal transport in metal foams

As a new-type extending surface, metal foam owns great potential in next generation heat transfer technologies. Convective heat transfer performance in metal foams is numerically investigated based on the local thermal equilibrium (LTE) model and the local thermal non-equilibrium (LTNE) model. The solid–fluid temperature difference and relative deviation are put forward for quantifying LTNE effect. The effects of basic parameters on heat transfer are analysed in depth and the LTNE conditions in metal-foam tube for efficient heat exchangers are summarized. It is indicated that the relative deviation is a more suitable criterion for LTNE effect in metal foam than the solid–fluid temperature difference. The LTNE effect in metal foam is conspicuous for low porosity, large fluid–solid thermal conductivity difference, small duct size, low pore density, and low Reynolds number. Measures lowering proportion of local convective thermal resistance in total thermal resistance, or the ratio of thermal resistance of solid to that of fluid can weaken LTNE effect in metal foam. There is no necessary relationship between thermal performance of metal-foam heat exchangers and corresponding LTNE effect. Clarifying LTNE conditions in porous foams can lay a foundation for the demarcating criterion of LTE/LTNE models. This can also guide quick and accurate thermal design and verification of metal-foam heat exchangers.

785 Impact of Key Factors of Enhanced Recovery Pathway and Preexisting Comorbidities on Complications and Length of Stay Following Colorectal Surgery

Background: Accurate prediction of postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) would help tailor optimal intraand postoperative management of this morbid complication. Distinct risk factors for ISGPF clinically relevant fistulas (CR-POPF), previously identified as small duct size, soft gland texture, high-risk pathology, and increased blood loss, are best discerned intraoperatively. The Fistula Risk Score (FRS), a 10 point scale derived at a single institution, relies on weighted influence of these four variables and has been shown to effectively predict (area under the curve of 0.942) CR-POPF development and its consequences. External validation of this tool would confirm its universal applicability. Methods: From 2001-2012, 594 PDs with pancreatojejunostomy reconstruction were performed by four pancreatic surgical specialists at three institutions. POPFs, when they occurred, were graded by ISGPF standards as biochemical (Grade A) or clinically relevant (Grades B and C). The FRS was calculated for each patient and clinical outcomes were evaluated across four discrete categories (Negligible Risk, 0 points; Low Risk, 1-2 points; Moderate Risk, 3-6 points; High Risk, 7-10 points). Receiver operator curve analysis was performed to judge model validity. Results: 142 patients developed any sort of POPF, of which 68 were CR-POPF (11.4% overall: 8.9% Grade B, 2.5% Grade C). There were 21 overall deaths, six of which were directly attributable to pancreatic fistula. Increasing FRS scores (0-10) correlated well with CR-POPF development (p,0.001), with an area under the curve of 0.716. When segregated by FRS risk groups, CR-POPFs occurred in Low, Moderate and High Risk patients 6.6%, 12.9% and 28.6% of the time respectively (figure). Clinical outcomes including complications, length of stay, and readmission rates, also increased across risk groups (table). Conclusion: This multi-institutional experience confirms the Fistula Risk Score as a valid tool for predicting the development of CR-POPF in patients undergoing pancreaticoduodenectomy. Patients devoid of any risk factors did not develop a CR-POPF, and the rate of CR-POPF approximately doubles with each subsequent risk zone. The lower value of the area under the curve in this analysis is attributable to the decreased rate of CR-POPF observed in the high risk group (29% vs. 89% originally). This difference might be ascribed to variations in operative technique, postoperative management styles, patient characteristics, and a larger sample size in the current study. Despite this, the FRS is validated as an accurate prediction tool, with widespread applicability, which can be readily translated into common practice.

The pancreaticojejunal anastomotic stent: Friend or foe?

The efficacy of pancreaticojejunal (P-J) anastomotic stents in preventing clinically relevant postoperative pancreatic fistulas (CR-POPF) after pancreatic resection is poorly understood. We sought to compare the outcomes of stented and nonstented patients in light of recognized risk-factors for the development of CR-POPF and to determine whether outcomes differed once there was a change in practice where use of stents was abandoned. A total of 444 patients underwent proximal pancreatic resection with P-J reconstruction from 2001 to 2011. At the surgeon's discretion, a PJ stent (5- or 8-Fr Silastic tube) was placed in 59 patients (13.3%; 46 internal, 13 external). Demographics, comorbidities, and adjusted outcomes were evaluated between groups of nonstented (n = 385) and stented patients; these outcomes included a subgroup analysis of internally and externally stented patients. Risk factors for CR-POPF (International Study Group on Pancreatic Fistula grade B/C) development have been previously defined as soft gland, small duct size, high-risk pathology, or excessive blood loss (>1,000 mL). Outcomes were interpreted in reference to the risk factor profile (the number of absolute risk factors present; 0-4), and to the fistula risk score, a prospectively validated score which accurately predicts the risk and impact of pancreatic fistula based on these variables. Preoperative demographics of age, sex, body mass index, American Society of Anesthesiologists class, and physiologic and operative severity score for the enumeration of mortality and morbidity (ie, POSSUM) score were equivalent between cohorts. The CR-POPF risk-factor profile and fistula risk score were greater in stented patients (P < .01). When compared with nonstented patients, stented patients actually had greater rates of CR-POPF (29% vs 11%), major complications (29% vs 14%), greater mean duration of stay (13.7 days vs 9.6 days), and total costs ($33,594 vs $22,411; all P < .05). When high-risk cases were scrutinized, P-J stent use did not offer protection, as CR-POPF was uniformly more common when stents were used. Rates and severity of CR-POPF did not increase when the use of stents was abandoned, further implying that they did not confer protection from fistula development. Extended postoperative imaging was available for 23 stented patients. Of these, one-third of stents were retained past 6 weeks, and one-fourth beyond 6 months. Four patients required additional procedures to manage stent-related complications. The use of P-J stents does not decrease the incidence or severity of CR-POPF after proximal pancreatic resection, both overall and for high-risk scenarios. In some patients, P-J stents may lead to short- and long-term adverse outcomes.

Histomorphological Features of the Pancreatic Remnant as Independent Risk Factors for Postoperative Pancreatic Fistula: A Matched-Pairs Analysis

Background/Aims: Postoperative pancreatic fistula (POPF) is a major complication after resective pancreatic surgery. This study aimed to identify histomorphological features of the pancreatic remnant as independent determinants for the development of POPF. Methods: Twenty-five patients, 3.6% of 696 resections over a period of 5 years, who developed POPF were matched for age, gender, diagnosis, comorbidities, surgeon and procedure with 25 controls without POPF. Pancreatic duct size and index, fibrosis grade, fat content, edema, and signs of chronic and acute inflammation were measured in frozen sections of the resection margin and were then compared. Results: The POPF rate was 12.2 and 2.6% after distal pancreatectomy and pancreatoduodenectomy, respectively. The POPF group was characterized by a longer ICU and total postoperative stay, higher rate of reoperations and complications. Their pancreata were softer at palpation (88 vs. 56%). Their pancreatic duct was smaller (2.5 vs. 3.2 mm) and their pancreatic fat content higher (16 vs. 8%). High inter- and intralobular fat content, small duct size, low interlobular fibrosis grade and lack of signs of chronic pancreatitis were predictors of POPF development. A score including these parameters identified high-risk patients with a sensitivity of 92% and a specificity of 84%. Conclusion: Histomorphological features of the pancreatic remnant play an independent role as risk factors for the development of POPF. A simple histological score based on the frozen sections may already intraoperatively predict the risk of POPF development.

Removable intraductal stenting in duct-to-duct biliary reconstruction in liver transplantation

Biliary reconstruction during liver transplantation (LT) is most oftenly performed by duct-to-duct biliary anastomosis. We hypothesized that the internal stenting might diminish the incidence and severity of biliary complications in patients receiving small duct size donor grafts. The purpose of this study was to report a technique of biliary reconstruction, including intraductal stent tube (IST) placement followed by postoperative endoscopic removal. A custom-made segment of a T-tube was placed into the bile in 20 patients in whom the diameter of the graft bile duct was smaller than 5 mm. The tube was removed endoscopically 4-8 months after LT, or in case of IST-related adverse events. After a median follow-up of 15.2 (range 2.5-27.5) months, endoscopic removal of the IST was performed in 17 patients. No technical failure and no procedure-related complications were recorded during drain removal. Biliary complications occurred in four patients, including one cholangitis, one hemobilia, one asymptomatic biliary leakage, and one anastomotic stricture. No biliary complication occurred in the group of patients who underwent deceased donor whole graft LT. IST is technically feasible and safe, and may help to prevent severe biliary complication when duct-to-duct biliary anastomosis is performed on small size bile ducts.

Risk Prediction for Development of Pancreatic Fistula Using the ISGPF Classification Scheme

The International Study Group on Pancreatic Fistula (ISGPF) classification scheme has become a useful system for characterizing the clinical impact of pancreatic fistula. We sought to identify predictive factors that predispose patients to fistula, specifically those with clinical relevance (grades B/C), and to describe the clinical and economic significance of risk stratification within this framework. Overall, 233 consecutive pancreatoduodenectomies were performed between October 2001 and March 2007 in our institution. Pancreatic fistula is defined according to the ISGPF classification scheme. Logistic regression analysis was performed to identify risk factors for pancreatic fistula development. These features were then analyzed to determine whether additive risk severity equates to worsening clinical and economic impact. Fistulas of any extent occurred in 60 patients, but only 31 (14%) were clinically relevant. There are no identifiable risk factors for grade A biochemical fistulas. Multivariate analysis shows that small pancreatic duct size (<3 mm); soft gland texture; ampullary, duodenal, cystic, or islet cell pathology; and increased intraoperative blood loss (>1,000 ml) are associated with clinically relevant fistulae. An additive effect is further illustrated, in which clinical and economic outcomes progressively worsen as risk profile increases. Each additional risk factor increases the odds of developing a clinically relevant fistula by 52%. For pancreatoduodenectomy, small duct size; soft gland texture; ampullary, duodenal, cystic, or islet cell pathology; and increased intraoperative blood loss are convincing risk factors for the development clinically relevant fistulae as judged by ISGPF classification. As risk profile accrues, patients suffer more complications, encounter longer hospital stays, and incur greater hospital costs. These outcomes can be predicted in the operating room through accurate delineation of high-risk glands.

Selective Administration of Prophylactic Octreotide During Pancreaticoduodenectomy: A Clinical and Cost-Benefit Analysis in Low- and High-Risk Glands

The efficacy of prophylactic octreotide after pancreaticoduodenectomy has been rigorously scrutinized, yet few studies have specifically illustrated its impact in patients at high risk for pancreatic fistula. Applying a previously validated clinical classification scheme (International Study Group on Pancreatic Fistula) for postoperative pancreatic fistula severity, we examined whether prophylactic octreotide could effectuate a clinical or fiscal benefit, or both, after pancreatic resection. There were 227 consecutive patients who underwent pancreaticoduodenectomy from October 2001 to January 2007. At the surgeon's discretion, prophylactic octreotide was administered intraoperatively and continued postoperatively. Clinically relevant fistulas, requiring therapeutic interventions or resulting in severe clinical sequelae, were identified, as were other complications. Through multivariate analysis, risk factors for fistula were defined as soft gland texture; small duct size; ampullary, duodenal, cystic, or islet cell pathology; and increased blood loss. Beyond a traditional review of clinical outcomes, a novel economic cost-benefit analysis of octreotide prophylaxis was performed, with concentration of impact on high-risk glands (one or more risk factors). Overall, 55% of patients had at least one risk factor. Clinically relevant fistulas were present in 14.9% of all patients. High-risk glands resulted in significantly worse clinical and economic outcomes compared with low-risk glands (no risk factors present). Prophylactic octreotide in low-risk glands was neither clinically effective nor cost efficient after pancreaticoduodenectomy, contributing to $781 in overspending per patient--approximately equivalent to a 7-day postoperative course of octreotide. But in patients with high-risk glands, octreotide prophylaxis was associated with a decreased incidence (20% versus 35%) and morbidity of clinically relevant fistulas. These improved clinical outcomes were associated with reduced resource use, translating to considerable cost savings ($11,849) per high-risk patient. Octreotide prophylaxis is an effective approach to mitigate the negative impact of pancreatic fistulas, but to obtain maximal clinical value and cost benefit, octreotide should be administered exclusively to patients with high-risk glands.

Needle-knife sphincterotomy in a tertiary referral center: efficacy and complications

Background: The use of needle-knife sphincterotomy as a method of precut sphincterotomy has been criticized as potentially unsafe. Despite this, a number of tertiary referral centers have reported their successful use of this technique to increase the rate of common bile duct cannulation. Methods: We assessed the safety and efficacy of needle-knife sphincterotomy in 72 consecutive patients in whom attempts at standard common bile duct cannulation were unsuccessful. Bile duct diameters were correlated to the complication rate. Results: Cannulation of the common bile duct was successful immediately after needle-knife sphincterotomy in 50 patients (67%), and was successful in 17 of the 20 patients who underwent repeat ERCP, for a total cannulation rate of 93%. Eight patients (11%) experienced complications. Retroduodenal perforation during guide wire cannulation attempts and bleeding occurred as frequently as pancreatitis. Small duct size was a risk factor for complications. There was no procedure-related mortality, and all complications were managed medically. Conclusions: Needle-knife sphincterotomy was effective in facilitating cannulation in patients in whom standard cannulation attempts failed. Limiting guide wire manipulation of the fresh sphincterotomy site and excluding patients with small duct size may further reduce the complication rate. (Gastrointest Endosc 1996;44:48-53.)