Endoscopic Ultrasound-guided Radiofrequency Ablation Versus Surgical Resection for Treatment of Pancreatic Insulinoma.

BACKGROUND & AIMS: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is emerging as a safe and effective treatment for pancreatic neuroendocrine tumors. We aimed to compare EUS-RFA and surgical resection for the treatment of pancreatic insulinoma (PI). METHODS: Patients with sporadic PI who underwent EUS-RFA at 23 centers or surgical resection at 8 high-volume pancreatic surgery institutions between 2014 and 2022 were retrospectively identified and outcomes compared using a propensity-matching analysis. Primary outcome was safety. Secondary outcomes were clinical efficacy, hospital stay, and recurrence rate after EUS-RFA. RESULTS: Using propensity score matching, 89 patients were allocated in each group (1:1), and were evenly distributed in terms of age, sex, Charlson comorbidity index, American Society of Anesthesiologists score, body mass index, distance between lesion and main pancreatic duct, lesion site, size, and grade. Adverse event (AE) rate was 18.0% and 61.8% after EUS-RFA and surgery, respectively (P < .001). No severe AEs were observed in the EUS-RFA group compared with 15.7% after surgery (P < .0001). Clinical efficacy was 100% after surgery and 95.5% after EUS-RFA (P = .160). However, the mean duration of follow-up time was shorter in the EUS-RFA group (median, 23 months; interquartile range, 14-31 months vs 37 months; interquartile range, 17.5-67 months in the surgical group; P < .0001). Hospital stay was significantly longer in the surgical group (11.1 ± 9.7 vs 3.0 ± 2.5 days in the EUS-RFA group; P < .0001). Fifteen lesions (16.9%) recurred after EUS-RFA and underwent a successful repeat EUS-RFA (11 patients) or surgical resection (4 patients). CONCLUSION: EUS-RFA is safer than surgery and highly effective for the treatment of PI. If confirmed in a randomized study, EUS-RFA treatment can become first-line therapy for sporadic PI.

Comparing per-pass performance of 2 types of needles for EUS-guided fine-needle biopsy sampling of pancreatobiliary masses in a randomized trial.

BACKGROUND AND AIMS: EUS-guided fine-needle biopsy sampling (EUS-FNB) has largely replaced FNA for tissue diagnosis of pancreatobiliary mass lesions. However, the optimal number of passes required for the diagnosis of malignancy is not clear. We aimed to compare the per-pass performance of 2 types of fine-needle biopsy (FNB) needles for the detection of malignancy. METHODS: One hundred fourteen patients referred for EUS evaluation of solid pancreatobiliary mass lesions underwent randomization between biopsy sampling with a Franseen needle and a 3-prong tip needle with an asymmetric cutting surfaces. Four passes of EUS-FNB were taken from each mass lesion. Two pathologists blinded to needle type analyzed the specimens. The final diagnosis of malignancy was made based on FNB specimen pathology, surgery, or a follow-up of at least 6 months after EUS-FNB. The sensitivity of EUS-FNB to diagnose malignancy was compared between the 2 groups. The cumulative sensitivity of detection of malignancy by EUS-FNB was calculated after each pass in each arm. Other characteristics of the specimens including cellularity and blood contents were also compared between the 2 groups. In the primary analysis, lesions categorized as suspicious on EUS-FNB were considered nondiagnostic for malignancy. RESULTS: Ninety-eight patients (86%) had a final diagnosis of malignancy, and 16 patients (14%) had benign disease. Four passes of EUS-FNB with the Franseen needle detected malignancy in 44 of 47 patients (sensitivity, 93.6%; 95% confidence interval [CI], 82.5-98.7) and with the 3-prong asymmetric-tip needle in 50 of 51 patients (sensitivity, 98%; 95% CI, 89.6-99.9; P = .35). Two passes of EUS-FNB detected malignancy with a sensitivity of 91.5% (95% CI, 79.6-97.6) with the Franseen needle and 90.2% (95% CI, 78.6-96.7) with the 3-prong asymmetric-tip needle. The cumulative sensitivities at pass 3 were 93.6% (95% CI, 82.5-98.6) and 96.1% (95% CI, 86.5-99.5), respectively. Samples collected with the Franseen needle had significantly higher cellularity than samples collected with the 3-prong asymmetric-tip needle (P < .01). However, no difference as found between the 2 types of needles in term of specimen bloodiness. CONCLUSIONS: No significant differences were found in the diagnostic performance of the Franseen needle versus the 3-prong asymmetric-tip needle in patients with suspected pancreatobiliary cancer. However, the Franseen needle yielded higher cellularity of the specimen. Two passes of EUS-FNB are required to detect malignancy with at least 90% sensitivity with either type of needle. (Clinical trial registration number: NCT04975620.).

Dietary intake of fatty acids and risk of pancreatic cancer: Golestan cohort study.

BACKGROUND: As pancreatic cancer (PC) is a malignancy with poor prognosis, finding strategies for its prevention became a notable priority. Among all the factors influencing the risk of PC, dietary items especially fats are considered as the most modifiable risk factors.This study is designed to assess the associations of dietary intake of fatty acids with the risk of PC incidence. METHODS: A total of 50,045 adults between 40 and 75 years old participated in this cohort study in 2004-2008 and were followed up to the present. Intakes of fatty acids was evaluated by validated food-frequency questionnaire (FFQ). Cox proportional hazards regression model was used to estimate hazard ratio (HR) with 95 % confidence interval of differing levels of dietary intakes of fatty acids for incidence of PC. RESULTS: At the end of follow-up period, 76 cases of PC were identified and 46,904 participants without history of cancer, acute kidney disorders, fibrosis and cirrhosis were included in the study. Dietary total saturated fatty acids (SFAS) was associated with PC risk (HR = 1.05 (1.01-1.09), Ptrend=0.01), whereas dietary total monounsaturated fatty acids (MUFAS) was inversely associated with the risk of PC (HR = 0.92 (0.86-0.99), Ptrend=0.04). Dietary total polyunsaturated fatty acids (PUFAS) did show a protective but not significant association with the risk of PC (HR = 0.91(0.84-1.00), Ptrend=0.05). CONCLUSIONS: The amount of total fat intake is not a risk factor for PC in our study and focusing on the intake of specific fatty acids becomes more striking. Unsaturated fatty acids including PUFAS and especially MUFAS are considered as protective dietary factors in PC prevention. In contrast, total SFAS is positively associated with the increased risk of PC. However, very long chain and odd-chain saturated fatty acids intake may be protective against PC.

Pharmacological prophylaxis versus pancreatic duct stenting plus pharmacological prophylaxis for prevention of post-ERCP pancreatitis in high risk patients: a randomized trial.

BACKGROUND: Acute pancreatitis is a serious complication of endoscopic retrograde cholangiopancreatography (ERCP). The aim of this noninferiority study was to evaluate the effectiveness of pancreatic duct (PD) stenting plus pharmacological prophylaxis vs. pharmacological prophylaxis alone in the prevention of post-ERCP pancreatitis (PEP) in high risk patients. METHODS: In this randomized, controlled, double-blind, noninferiority trial, patients at high risk of developing PEP were randomly allocated to pharmacological prophylaxis (rectal indomethacin, sublingual isosorbide dinitrate, and intravenous hydration with Ringer's lactate) plus PD stenting (group A) or pharmacological prophylaxis alone (group B). The rate and severity of PEP, serum amylase levels, and length of hospital stay after ERCP were assessed. RESULTS: During 21 months, a total of 414 patients (mean age 55.5 ±â€Š17.0 years; 60.2 % female) were enrolled (207 in each group). PEP occurred in 59 patients (14.3 %, 95 % confidence interval [CI] 11.1 % - 17.9 %: 26 patients [12.6 %, 95 %CI 8.6 % - 17.6 %] in group A and 33 [15.9 %, 95 %CI 11.4 % - 21.4 %] in group B). There was no significant difference between the two groups in PEP severity (P = 0.59), amylase levels after 2 hours (P = 0.31) or 24 hours (P = 0.08), and length of hospital stay (P = 0.07). CONCLUSIONS: The study failed to demonstrate noninferiority or inferiority of pharmacological prophylaxis alone compared with PD stenting plus pharmacological prophylaxis in the prevention of PEP in high risk patients.

Increasing Number of Passes Beyond 4 Does Not Increase Sensitivity of Detection of Pancreatic Malignancy by Endoscopic Ultrasound-Guided Fine-Needle Aspiration.

BACKGROUND & AIMS: It is not clear exactly how many passes are required to determine whether pancreatic masses are malignant using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We aimed to define the per-pass diagnostic yield of EUS-FNA for establishing the malignancy of a pancreatic mass, and identify factors associated with detection of malignancies. METHODS: In a prospective study, 239 patients with solid pancreatic masses were randomly assigned to groups that underwent EUS-FNA, with the number of passes determined by an on-site cytopathology evaluation or set at 7 passes, at 3 tertiary referral centers. A final diagnosis of pancreatic malignancy was made based on findings from cytology, surgery, or a follow-up evaluation at least 1 year after EUS-FNA. The cumulative sensitivity of detection of malignancy by EUS-FNA was calculated after each pass; in the primary analysis, lesions categorized as malignant or suspicious were considered as positive findings. RESULTS: Pancreatic malignancies were found in 202 patients (84.5% of the study population). EUS-FNA detected malignancies with 96% sensitivity (95% confidence interval [CI], 92%-98%); 4 passes of EUS-FNA detected malignancies with 92% sensitivity (95% CI, 87%-95%). Tumor size greater than 2 cm was the only variable associated with positive results from cytology analysis (odds ratio, 7.8; 95% CI, 1.9-31.6). In masses larger than 2 cm, 4 passes of EUS-FNA detected malignancies with 93% sensitivity (95% CI, 89%-96%) and in masses ≤2 cm, 6 passes was associated with 82% sensitivity (95% CI, 61%-93%). Sensitivity of detection did not increase with increasing number of passes. CONCLUSIONS: In a prospective study, we found 4 passes of EUS-FNA to be sufficient to detect malignant pancreatic masses; increasing the number of passes did not increase the sensitivity of detection. Tumor size greater than 2 cm was associated with malignancy, and a greater number of passes may be required to evaluate masses 2 cm or less. ClinicalTrials.gov number, NCT01386931.

Diagnostic yield of EUS-guided FNA for malignant biliary stricture: a systematic review and meta-analysis.

BACKGROUND AND AIMS: EUS-guided FNA (EUS-FNA) is increasingly being used for tissue diagnosis of extrahepatic biliary strictures. The aim of this study was to determine the diagnostic yield of EUS-FNA in malignant biliary strictures. METHODS: A comprehensive literature review was carried out by 2 reviewers for studies evaluating the accuracy of EUS-FNA in biliary stricture. A meta-analysis was performed to determine the pooled estimates of sensitivity, specificity, likelihood ratios, and diagnostic odds ratio for EUS-FNA of extrahepatic biliary stricture. A Quality Assessment of Diagnostic Accuracy Studies questionnaire was used to assess the quality of the selected studies. Several sensitivity analyses were performed to assess the effect of the quality of the studies on the accuracy of the final results of the meta-analysis. RESULTS: Twenty studies involving 957 patients met inclusion criteria and were included in the meta-analysis. The pooled sensitivity and specificity of EUS-FNA for diagnosis of malignant biliary stricture were 80% (95% confidence interval [CI], 74%-86%), and 97% (95% CI, 94%-99%), respectively. The pooled positive likelihood ratio was 12.35 (95% CI, 7.37-20.72), and the negative likelihood ratio was 0.26 (95% CI, 0.18-0.38). The pooled diagnostic odds ratio for diagnosing a malignant biliary stricture was 70.53 (95% CI, 38.62-128.82). The area under the receiver-operating characteristic curve was 0.97. Sensitivity analyses showed that the quality of the included studies did not affect the accuracy of the final results of the meta-analysis. CONCLUSION: This meta-analysis demonstrates that EUS-FNA is sensitive and highly specific for diagnosing malignancy in biliary strictures. Further studies are needed to compare EUS--FNA with emerging methods including cholangioscopy-guided biopsy and laser endomicroscopy.

Risk factors associated with the transmission of carbapenem-resistant Enterobacteriaceae via contaminated duodenoscopes.

BACKGROUND AND AIMS: The duodenoscopes used to perform ERCP have been implicated in several outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) infection. The risk factors for CRE transmission via contaminated duodenoscopes remain unclear. METHODS: In this retrospective, single-center, case-control study, all patients who underwent ERCP with either 1 of 2 contaminated duodenoscopes were evaluated. We compared the patients who acquired CRE (active infection or colonization) with those who did not. RESULTS: Between October 3, 2014, and January 28, 2015, a total of 125 procedures were performed on 115 patients by using either of the contaminated duodenoscopes. Culture data were available for 104 of the 115 exposed patients (90.4%). Among these patients, 15 (14.4%) became actively infected (n = 8, 7.7%) or colonized (n = 7, 6.7%) with CRE. On univariate analysis, recent antibiotic exposure (66.7% vs 37.1%; P = .046), active inpatient status (60.0% vs 28.1%; P = .034), and a history of cholangiocarcinoma (26.7% vs 3.4%; P = .008) were patient characteristics associated with an increased risk of CRE infection. Biliary stent placement (53.3% vs 22.5%; P = .024) during ERCP was a significant procedure-related risk factor. After adjusting for cholangiocarcinoma, biliary stent placement (odds ratio 3.62; 95% confidence interval, 1.12-11.67), and active inpatient status (odds ratio 3.74; 95% confidence interval, 1.15-12.12) remained independent risk factors for CRE transmission. CONCLUSIONS: In patients undergoing ERCP with a contaminated duodenoscope, biliary stent placement, a diagnosis of cholangiocarcinoma, and active inpatient status are associated with an increased risk of CRE transmission.

Utility of endoscopic ultrasound to diagnose remnant stones in symptomatic patients after cholecystectomy.

BACKGROUND AND STUDY AIMS: Stones in the cystic duct stump (CDS) or gallbladder remnant after cholecystectomy are difficult to identify. The aim of this study was to evaluate the utility of endoscopic ultrasound (EUS) in the diagnosis of stones in the CDS or gallbladder remnant in patients with postcholecystectomy syndrome. METHODS: A prospective study was conducted between January 2011 and December 2012 in consecutive patients with pancreaticobiliary-type pain or acute pancreatitis (n = 112) following cholecystectomy. Diagnostic modalities including EUS were used to diagnose the cause of postcholecystectomy syndrome. RESULTS: A total of 11 patients (10 %) were found to have stones in the gallbladder remnant (n = 8), CDS (n = 2), or both (n = 1). In eight patients, EUS was the first imaging procedure to make the diagnosis. Seven patients agreed to undergo repeat surgery, and six of them remained free of symptoms postoperatively after a median follow-up period of 4 months (range 1 - 13 months). CONCLUSION: EUS may be an important procedure to consider in the study of patients with symptoms after cholecystectomy, as the diagnosis of residual stones is frequently missed by other imaging modalities.

Impact of preoperative endoscopic ultrasound-guided fine needle aspiration on postoperative recurrence and survival in cholangiocarcinoma patients.

BACKGROUND AND STUDY AIM: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is frequently performed for suspected biliary tumors for diagnosis and staging but carries a theoretical risk of needle-track seeding. We aimed to evaluate the impact of preoperative EUS-FNA on long-term outcomes for patients with cholangiocarcinoma (CCA). PATIENTS AND METHODS: In a retrospective single-center study of consecutive patients with CCA with preoperative EUS-FNA, main outcome measures were overall survival and progression-free survival. RESULTS: In 150 patients with confirmed CCA, 61 underwent preoperative FNA. Median overall survival was 18.5 months (95% confidence limits [CL] 15.4, 25.7): 111 patients died and 39 survived. Of the 150 patients, 119 underwent curative-intent surgical resection, with median progression-free survival of 17.8 months (95% CL 14.5, 22.8); 89/119 patients had tumor recurrence or died, and 30/119 remained alive and disease-free. On multivariable analysis, overall survival was associated with: undergoing curative-intent surgery (hazard ratio [HR] 5.79, P = 0.001), lack of lymph node involvement (HR 1.89, P = 0.011), younger age (HR 1.51 for every 10 years, P < 0.0015), and small tumor size (HR 1.11 for every 1 cm, P = 0.029). For patients undergoing curative-intent surgery, on multivariable analysis, improved progression-free survival was associated with: lack of lymph node involvement (HR 1.88, P = 0.010), smaller tumor size (HR 1.16 for every 1 cm smaller, P = 0.003), and younger age (HR 1.53 for every 10 years, P < 0.001). Number of needle passes showed no statistically significant impact on overall survival. CONCLUSION: Preoperative EUS-FNA in patients with CCA does not appear to adversely affect overall or progression-free survival.

Randomized placebo-controlled trial of mesenchymal stem cell transplantation in decompensated cirrhosis.

BACKGROUND & AIMS: There has been great interest in recent years to take advantage of bone marrow stem cells to treat cirrhosis. Our uncontrolled trial showed promising results for bone marrow mesenchymal stem cell (MSC) transplantation in cirrhosis. Therefore, we conducted a randomized, placebo-controlled trial to evaluate the efficacy of autologous MSC transplantation in cirrhosis. METHODS: The enrolled patients with decompensated cirrhosis were randomly assigned to receive MSC or placebo infusions. A median of 195 million (range: 120-295 million) cultured MSCs were infused through a peripheral vein. The primary outcome was absolute changes in MELD score. Secondary outcomes were absolute changes in Child score, liver function tests and liver volumes between the MSC and placebo group 12 months after infusion. RESULTS: A total of 27 patients were enrolled. Of these, 15 patients received MSC and 12 patients received placebo. One patient in the MSC group and one patient in the placebo group were lost to follow-up. Three patients in the MSC group died of liver failure 3 months (one patient), or 5 months (two patients) after cellular infusion. The baseline MELD scores of the deceased patients were significantly higher than those who remained alive in either group (20.0 vs. 15.1; P = 0.02). The absolute changes in Child scores, MELD scores, serum albumin, INR, serum transaminases and liver volumes did not differ significantly between the MSC and placebo groups at 12 months of follow-up. CONCLUSION: Based on this randomized controlled trial, autologous bone marrow MSC transplantation through peripheral vein probably has no beneficial effect in cirrhotic patients. Further studies with higher number of patients are warranted to better clarify the impact of MSC infusion through peripheral vein or portal vein in cirrhosis.

Cell and cell-derivative-based therapy for liver diseases: current approaches and future promises.

INTRODUCTION: According to the recent updates from World Health Organization, liver diseases are the 12th most common cause of mortality. Currently, orthotopic liver transplantation (OLT) is the most effective and the only treatment for end-stage liver diseases. Owing to several shortcomings like finite numbers of healthy organ donors, lifelong immunosuppression, and complexity of the procedure, cell and cell-derivatives therapies have emerged as a potential therapeutic alternative for liver diseases. Various cell types and therapies have been proposed and their therapeutic effects evaluated in preclinical or clinical studies, including hepatocytes, hepatocyte-like cells (HLCs) derived from stem cells, human liver stem cells (HLSCs), combination therapies with various types of cells, organoids, and implantable cell-biomaterial constructs with synthetic and natural polymers or even decellularized extracellular matrix (ECM). AREAS COVERED: In this review, we highlighted the current status of cell and cell-derivative-based therapies for liver diseases. Furthermore, we discussed future prospects of using HLCs, liver organoids, and their combination therapies. EXPERT OPINION: Promising application of stem cell-based techniques including iPSC technology has been integrated into novel techniques such as gene editing, directed differentiation, and organoid technology. iPSCs offer promising prospects to represent novel therapeutic strategies and modeling liver diseases.

Acetaminophen-induced hepatotoxicity in mice is dependent on Tlr9 and the Nalp3 inflammasome.

Hepatocyte death results in a sterile inflammatory response that amplifies the initial insult and increases overall tissue injury. One important example of this type of injury is acetaminophen-induced liver injury, in which the initial toxic injury is followed by innate immune activation. Using mice deficient in Tlr9 and the inflammasome components Nalp3 (NACHT, LRR, and pyrin domain-containing protein 3), ASC (apoptosis-associated speck-like protein containing a CARD), and caspase-1, we have identified a nonredundant role for Tlr9 and the Nalp3 inflammasome in acetaminophen-induced liver injury. We have shown that acetaminophen treatment results in hepatocyte death and that free DNA released from apoptotic hepatocytes activates Tlr9. This triggers a signaling cascade that increases transcription of the genes encoding pro-IL-1beta and pro-IL-18 in sinusoidal endothelial cells. By activating caspase-1, the enzyme responsible for generating mature IL-1beta and IL-18 from pro-IL-1beta and pro-IL-18, respectively, the Nalp3 inflammasome plays a crucial role in the second step of proinflammatory cytokine activation following acetaminophen-induced liver injury. Tlr9 antagonists and aspirin reduced mortality from acetaminophen hepatotoxicity. The protective effect of aspirin on acetaminophen-induced liver injury was due to downregulation of proinflammatory cytokines, rather than inhibition of platelet degranulation or COX-1 inhibition. In summary, we have identified a 2-signal requirement (Tlr9 and the Nalp3 inflammasome) for acetaminophen-induced hepatotoxicity and some potential therapeutic approaches.

Utility of EUS-guided biopsy of extramural pelvic masses.

BACKGROUND: The diagnostic utility of EUS-guided FNA (EUS-FNA) and EUS-guided Trucut biopsy (EUS-TCB) of pelvic masses has not been well described. OBJECTIVE: To evaluate the utility of EUS in the diagnosis of pelvic masses. DESIGN: Retrospective cohort study. SETTING: Single tertiary referral hospital in Indianapolis, Indiana. PATIENTS: Consecutive patients referred for EUS evaluation of pelvic mass from January 2002 to July 2009. Patients with newly diagnosed rectal cancer or a known/suspected intramural mass were excluded. INTERVENTIONS: EUS-FNA and/or EUS-TCB. MAIN OUTCOME MEASUREMENTS: Endosonographic features and cytological and pathological findings were evaluated. The final diagnosis was confirmed by surgical pathology or cytology and clinical follow-up. The sensitivities and specificities of EUS-TCB were calculated in a subset of patients with available surgical pathology. RESULTS: A total of 69 patients were identified, and 40 with intramural lesions (n = 36) or incomplete follow-up (n = 4) were excluded. The remaining 29 patients (15 men, mean age 58.5 ± 10.8 years) with pelvic masses (mean size 40.8 ± 20.1 mm) were evaluated. EUS-FNA or EUS-TCB helped to make the diagnosis in 25 of 29 patients (86%). Compared with surgical pathology (available in 17 patients), EUS-FNA had a sensitivity of 88% (95% CI, 53%-98%) and specificity of 100% (95% CI, 65%-100%) for malignancy. EUS-TCB alone had a sensitivity of 67% (95% CI, 21%-94%) and specificity of 100% (95% CI, 34%-100%) for malignancy, but the combination of EUS-FNA and EUS-TCB had a sensitivity of 100% (95% CI, 68%-100%) and a specificity of 100% (95% CI, 68%-100%). Complications after EUS-FNA included a pelvic abscess in 2 patients (7%) with a cystic pelvic mass. LIMITATION: Single-center study. CONCLUSION: EUS-FNA and EUS-TCB are sensitive for the diagnosis of malignancy in pelvic masses. Sampling of cystic masses in this region is discouraged.

Intrahepatic aneurysmal portosystemic venous shunt diagnosed on EUS.

Video 1EUS demonstration of aneurysmal intrahepatic portosystemic venous shunt.

Endoscopic or surgical treatment for necrotizing pancreatitis: Comprehensive systematic review and meta-analysis.

Background and study aims Treatment of necrotizing pancreatitis is changed over the past two decades with the availability of endoscopic, and minimally invasive surgical approaches. The aim of this systematic review was to assess outcomes of endoscopic drainage, and different types of surgical drainage approaches in necrotizing pancreatitis. Methods Medline, Embase, Scopus, and Web of Science were searched from 1998 to 2020 to assess outcomes in endoscopic drainage and various surgical drainage procedures. The assessed variables consisted of mortality, development of pancreatic or enteric fistula, new onset diabetes mellitus, and exocrine pancreatic insufficiency. Results One hundred seventy studies comprising 11,807 patients were included in the final analysis. The pooled mortality rate was 22 % (95 % confidence interval [CI]: 19%-26 %) in the open surgery (OS), 8 % (95 %CI:5 %-11 %) in minimally invasive surgery (MIS), 13 % (95 %CI: 9 %-18 %) in step-up approach, and 3 % (95 %CI:2 %-4 %) in the endoscopic drainage (ED). The pooled rate of fistula formation was 35 % (95 %CI:28 %-41 %) in the OS, 17 % (95 %CI: 12%-23 %) in MIS, 17 % (95 %CI: 9 %-27 %) in step-up approach, and 2 % (95 %CI: 0 %-4 %) in ED. There were 17 comparative studies comparing various surgical drainage methods with ED. The mortality rate was significantly lower in ED compared to OS (risk ratio [RR]: 30; 95 %CI: 0.20-0.45), and compared to MIS (RR: 0.40; 95 %CI: 0.26-0.6). Also, the rate of fistula formation was lower in ED compared to all other surgical drainage approaches. Conclusions This systematic review demonstrated lower rate of fistula formation with ED compared to various surgical drainage methods. A lower rate of mortality with ED was also observed in observational studies. PROSPERO Identifier: CRD42020139354.

Mesenchymal Stromal Cell Therapy Improves Refractory Perianal Fistula in Crohn's Disease: Case Series Clinical Interventional Study.

Objective: Perianal fistulas in Crohn's disease (CD) are the main challenges in inflammatory bowel diseases (IBDs). Some of the fistulas are refractory to any therapeutic strategy. The aim of this study was to evaluate the therapeutic effects of mesenchymal stromal cells (MSCs) as a novel promising modality for the treatment of fistulizing CD. Materials and Methods: This case series clinical interventional study was conducted from 2014 to 2017 at Shariati Hospital, an IBD referral center in Tehran, Iran. Refractory adult patients with CD who had draining perianal fistulas were enrolled in this study. All patients were examined by a colorectal surgeon and the fistula imaging studies were performed by pelvic magnetic resonance imaging (MRI). After autologous bone marrow (BM) aspiration and MSCs isolation, the cells were cultured and passaged under current good manufacturing practice (cGMP) conditions. Four intra-fistula injections of cells, each containing 40×106 MSCs suspended in fibrin glue, were administered by an expert surgeon every 4 weeks. Procedure safety, feasibility and closure of the perianal fistulas at week 24 were assessed. Clinical examination and MRI findings were considered as the primary end points. Results: In total, 5 patients (2 males and 3 females) were enrolled in this study. No adverse events were observed during the six-month follow-up in these patients. Both the Crohn's Disease Activity Index (CDAI) and Perianal Disease Activity Index (PDAI) scores decreased in all patients after cell injections and one patient achieved complete remission with closure of fistulas, discontinuation of fistula discharge, and closure of the external opening. Conclusion: Local injection of MSCs combined with fibrin glue is potentially a safe and effective therapeutic approach for complex perianal fistulas in patients with CD.