Outcomes of colon self-expandable metal stents for malignant vs benign indications at a tertiary care center and review of literature

BACKGROUND Endoscopic placement of a self-expandable metal stent(SEMS)is a minimally invasive treatment for use in malignant and benign colonic obstruction.However,their widespread use is still limited with a nationwide analysis showing only 5.4%of patients with colon obstruction undergoing stent placement.This underutilization could be due to perceived increase risk of complications with stent placement.AIM To review long-and short-term clinical success of SEMS use for colonic obstruction at our center.METHODS We retrospectively reviewed all the patients who underwent colonic SEMS placement over aeighteen year period (August 2004 through August 2022) at our academic center. Demographicsincluding age, gender, indication (malignant and benign), technical success, clinical success,complications (perforation, stent migration), mortality, and outcomes were recorded.RESULTSSixty three patients underwent colon SEMS over an 18-year period. Fifty-five cases were formalignant indications, 8 were for benign conditions. The benign strictures included diverticulardisease stricturing (n = 4), fistula closure (n = 2), extrinsic fibroid compression (n = 1), and ischemicstricture (n = 1). Forty-three of the malignant cases were due to intrinsic obstruction from primaryor recurrent colon cancer;12 were from extrinsic compression. Fifty-four strictures occurred on theleft side, 3 occurred on the right and the rest in transverse colon. The total malignant case (n = 55)procedural success rate was 95% vs 100% for benign cases (P = 1.0, NS). Overall complication ratewas significantly higher for benign group: Four complications were observed in the malignantgroup (stent migration, restenosis) vs 2 of 8 (25%) for benign obstruction (1-perforation, 1-stentmigration) (P = 0.02). When stratifying complications of perforation and stent migration there wasno significant difference between the two groups (P = 0.14, NS).CONCLUSIONColon SEMS remains a worthwhile option for colonic obstruction related to malignancy and has ahigh procedural and clinical success rate. Benign indications for SEMS placement appear to havesimilar success to malignant. While there appears to be a higher overall complication rate inbenign cases, our study is limited by sample size. When evaluating for perforation alone theredoes not appear to be any significant difference between the two groups. SEMS placement may bea practical option for indications other that malignant obstruction. Interventional endoscopistsshould be aware and discuss the risk for complications in setting of benign conditions. Indicationsin these cases should be discussed in a multi-disciplinary fashion with colorectal surgery.

Evaluation of Patients with Severe Aortic Stenosis after TAVI with Self-Expandable vs. Balloon-Expandable Devices

Background: The introduction of transcatheter aortic valve implantation (TAVI) for the treatment of severe aortic stenosis (SAS) has expanded the therapeutic possibilities for successfully managing SAS in cases with intermediate and high surgical risks. However, the complications and outcomes of new devices have not been studied enough. Hence, the purpose of this study is to evaluate the midterm results of the Core Valve and Evolute R self-expandable (SE) devices versus the Edwards SAPIEN balloon-expandable (BE) devices. Methods and Material: This was a quasi-experimental study conducted in Tehran, Iran, from May 2012 to June 2017. SAS patients who were not ideal candidates for surgery were randomly assigned to either SE or BE groups. For each patient, a questionnaire, including four sections comprised of Basic characteristics, echocardiographic, angiographic, and Computed Tomography (CT) scan data was filled. TAVI was followed by echocardiography a week later and after three months they were reevaluated by another questionnaire. Results: The total number of patients was 60. The mean ages of patients undergoing the procedure with SE or BE devices were 81.2 ± 8 and 79.8 ± 7, respectively. Mortality occurred in 20% of the patients (5 cases in the SE group and 7 cases in the BE);mortality causes were 66.6 % cardiac and 33% non-cardiac. Moderate to severe Paravalvular leakage in both groups did not differ significantly. The mortality rate was 5 (41.6%) in the SE group versus 7 (58.3%) in the BE group (P > 0.05). Conclusion: In conclusion, the BE group did not experience fewer paravalvular leaks in comparison with the SE. Morbidity and mortality between the BE and the SE groups did not differ significantly.

Self-expandable metallic stent placement plus laparoscopy for acute malignant colorectal obstruction

AIM:To investigate the clinical advantages of the stent-laparoscopy approach to treat colorectal cancer(CRC)patients with acute colorectal obstruction(ACO).METHODS:From April 2008 to April 2012,surgeryrelated parameters,complications,overall survival(OS),and disease-free survival(DFS)of 74 consecutive patients with left-sided CRC presented with ACO who underwent self-expandable metallic stent(SEMS)placement followed by one-stage open(n=58)or laparoscopic resection(n=16)were evaluated retrospectively.The stent-laparoscopy group was also compared with a control group of 96 CRC patients who underwent regular laparoscopy without ACO between January 2010 and December 2011 to explore whether SEMS placement influenced the laparoscopic procedure or reduced long-term survival by influencing CRC oncological characteristics.RESULTS:The characteristics of patients among these groups were comparable.The rate of conversion to open surgery was 12.5%in the stent-laparoscopy group.Bowel function recovery and postoperative hospital stay were significantly shorter(3.3±0.9 d vs 4.2±1.5 d and 6.7±1.1 d vs 9.5±6.7 d,P=0.016 and P=0.005),and surgical time was significantly longer(152.1±44.4 min vs 127.4±38.4 min,P=0.045)in the stent-laparoscopy group than in the stent-open group.Surgery-related complications and the rate of admission to the intensive care unit were lower in the stent-laparoscopy group.There were no significant differences in the interval between stenting and surgery,intraoperative blood loss,OS,and DFS between the two stent groups.Compared with those in the stentlaparoscopy group,all surgery-related parameters,complications,OS,and DFS in the control group were comparable.CONCLUSION:The stent-laparoscopy approach is a feasible,rapid,and minimally invasive option for patients with ACO caused by left-sided CRC and can achieve a favorable long-term prognosis.

Clinical outcomes of self-expandable stent placement for benign esophageal diseases: A pooled analysis of the literature

AIM: To analyze the outcomes of self-expandable stent placement for benign esophageal strictures and benign esophageal leaks in the literature.METHODS: The Pub Med, Embase and Cochrane databases were searched for relevant articles published between January 2000 and July 2014. Eight prospective studies were identified that analyzed the outcomes of stent placement for refractory benign esophageal strictures. The outcomes of stent placement for benign esophageal leaks, perforations and fistulae were extracted from 20 retrospective studies that were published after the inclusion period of a recent systematic review. Data were pooled and analyzed using descriptive statistics.RESULTS: Fully covered self-expandable metal stents(FC SEMS)(n = 85), biodegradable(BD) stents(n = 77) and self-expandable plastic stents(SEPS)(n = 70) were inserted in 232 patients with refractory benign esophageal strictures. The overall clinical success rate was 24.2% and according to stent type 14.1% for FC SEMS, 32.9% for BD stents and 27.1% for SEPS. Stent migration occurred in 24.6% of cases. The overall complication rate was 31.0%, including major(17.7%) and minor(13.4%) complications. A total of 643 patients were treated with self-expandable stents mainly for postsurgical leaks(64.5%), iatrogenic perforations(19.6%), Boerhaave's syndrome(7.8%) and fistulae(3.7%). FC SEMS and partially covered SEMS were used in the majority of patients. Successful closure of the defect was achieved in 76.8% of patients and according to etiology in 81.4% for postsurgical leaks, 86.0% for perforations and 64.7% for fistulae. The pooled stent migration rate was 16.5%. Stent-related complications occurred in 13.4% of patients, including major(7.8%) and minor(5.5%) complications.CONCLUSION: The outcomes of stent placement for refractory benign esophageal strictures were poor. However, randomized trials are needed to put this into perspective. The evidence on successful stent placement for benign esophageal leaks, perforationsand fistulae is promising.

Self-expandable metal stents in patients with postoperative delayed gastric emptying after distal gastrectomy

AIM To investigate the efficacy and safety of endoscopic stent insertion in patients with delayed gastric emptying after gastrectomy.METHODS In this study, we prospectively collected data from patients who underwent stent placement for delayed gastric emptying(DGE) after distal gastrectomy between June 2010 and April 2017, at a tertiary referral academic center. Clinical improvement, complications, and consequences after stent insertion were analyzed.RESULTS Technical success was achieved in all patients(100%). Early symptom improvement was observed in 15 of 20 patients(75%) and clinical success was achieved in all patients. Mean follow-up period was 1178.3 ± 844.1 d and median stent maintenance period was 51 d(range 6-2114 d). During the follow-up period, inserted stents were passed spontaneously per rectum without any complications in 14 of 20 patients(70%). Symptom improvement was maintained after stent placement without the requirement of any additional intervention in 19 of 20 patients(95%).CONCLUSION Endoscopic stent placement provides prompt relief of obstructive symptoms. Thus, it can be considered an effective and safe salvage technique for post-operative DGE.

Feasibility and safety of self-expandable metal stent in nonmalignant disease of the lower gastrointestinal tract

In recent years,self-expandable metal stents(SEMSs)have been employed to treat benign gastrointestinal strictures secondary to several conditions:Acute diverticulitis,radiation colitis,inflammatory bowel disease(IBD),and postanastomotic leakages and stenosis.Other applications include endometriosis and fistulas of the lower gastrointestinal tract.Although it may be technically feasible to proceed to stenting in the aforementioned benign diseases of the lower gastrointestinal tract,the outcome has been reported to be poor.In fact,in some settings(such as complicated diverticulitis and postsurgical anastomotic strictures),stenting seems to have a limited evidence-based benefit as a bridge to surgery,while in other settings(such as endometriosis,IBD,radiation colitis,etc.),even society guidelines are not able to guide the endoscopist through decisional algorithms for SEMS placement.The aim of this narrative paper is to review the scientific evidence regarding the use of SEMSs in nonmalignant diseases of the lower gastrointestinal tract,both in adult and pediatric settings.

Management of post-gastrectomy anastomosis site obstruction with a self-expandable metallic stent

Post-gastrectomy anastomosis site obstruction is a relatively rare complication after a subtotal gastrectomy.We present a case of a 75-year-old man who underwent a truncal vagotomy, omental patch, gastrojejunostomy, and Braun anastomosis for duodenal ulcer perforation and a gastric outlet obstruction.Following the 10 th postoperative day, the patient complained of abdominal discomfort and vomiting.We diagnosed post-gastrectomy anastomosis site obstruction by an upper gastrointestinal series and an upper endoscopic examination.We inserted a self-expandable metallic stent(SEMS) at the anastomosis site.The stent was fully expanded after deployment.On the day following the stent insertion, the patient began to eat, and his abdominal discomfort was resolved.This paper describes the successful management of post-gastrectomy anastomosis site obstruction with temporary placement of a SEMS.

Evaluation of anti-migration properties of biliary covered self-expandable metal stents

AIM: To assess anti-migration potential of six biliary covered self-expandable metal stents(C-SEMSs) by using a newly designed phantom model. METHODS: In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration(RFM) was measured by a force gauge on the stent end. Radial force(RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare(ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model.RESULTS: Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables(ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state.CONCLUSION: RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

Resolution of an esophageal leak and posterior gastric wall necrosis with esophageal self-expandable metal stents

The use of weight reduction surgeries has increased over the years with a higher proportion of these surgeries being sleeve gastrectomies,this has been associated with some complications including staple line leaks.We report a 32-year-old male who had undergone a laparoscopic gastric band surgery and subsequently a laparoscopic sleeve gastrectomy,this was complicated by both an staple line leak at the gastroesophageal junction as well as a large(> 4 cm) posterior gastric wall defect due to gastric wall necrosis. We used two co-axially inserted self-expandable stents(SEMS) in the management of this patient,5 stents were used over repeated endoscopy sessions and 20 wk. Both defects had resolved without the need for surgical intervention.This is the first reported case were SEMS are used for both a staple line leak as well as a gastric wall defect.We also review the literature on the use of SEMS in the management of leaks post weight reduction surgeries.

Revision of bilateral self-expandable metallic stents placed using the stent-in-stent technique for malignant hilar biliary obstruction

Background: Endoscopic biliary decompression using bilateral self-expandable metallic stent(SEMS) placed using the stent-in-stent(SIS) technique is considered favorable for unresectable malignant hilar biliary obstruction(MHBO). However, occlusion of the bilateral SIS placement is frequent and revision can be challenging. This study was performed to investigate the efficacy, the long-term patency and the appropriate approach for revision of occluded bilateral SIS placement in unresectable MHBO. Methods: From January 2011 to July 2016, thirty-eight patients with unresectable MHBO underwent revision of occluded bilateral SIS placement. Clinical data including success rates and patency of revision, were retrospectively analyzed. Results: The technical success rate of revision was 76.3%. The clinical success rate of revision was 51.7% and mean patency of revision was 49.1 days. No significant predictive factor for clinical failure of revision was observed. The cell size of SEMS was not found to have significant effects on clinical success rates or revision patency. Conclusions: Revision of occluded bilateral SIS placement for MHBO showed fair patency and clinical success rate. Revision method and cell size of SEMS were not found to influence clinical outcomes.

Placement of a fully covered self-expandable metal stent in a young patient with chronic pancreatitis

Plastic stent insertion is a treatment option for pancreatic duct stricture with chronic pancreatitis.However, recurrent stricture is a limitation after removing the plastic stent.Self-expandable metal stents have long diameters and patency.A metal stent has become an established management option for pancreatic duct stricture caused by malignancy but its use in benign stricture is still controversial.We introduce a young patient who had chronic pancreatitis and underwent several plastic stent insertions due to recurrent pancreatic duct stricture.His symptoms improved after using a fully covered self-expandable metal covered stent and there was no recurrence found at follow-up at the outpatient department.

Chronic pancreatic pain successfully treated by endoscopic ultrasound-guided pancreaticogastrostomy using fully covered self-expandable metallic stent

One of the most common symptoms presenting in patients with chronic pancreatitis is pancreatic-type pain.Obstruction of the main pancreatic duct in chronic pancreatitis can be treated by a multitude of therapeutic approaches,ranging from pharmacologic,endoscopic and radiologic treatments to surgical interventions.When the conservative treatment approaches fail to resolve symptomatic cases,however,endoscopic retrograde pancreatography with pancreatic duct drainage is the preferred second approach,despite its well-recognized drawbacks.When the conventional transpapillary approach fails to achieve the necessary drainage,the patients may benefit from application of the less invasive endoscopic ultrasound(EUS)-guided pancreatic duct interventions.Here,we describe the case of a 42-year-old man who presented with severe abdominal pain that had lasted for 3 mo.Computed tomography scanning showed evidence of chronic obstructive pancreatitis with pancreatic duct stricture at genu.After conventional endoscopic retrograde pancreaticography failed to eliminate the symptoms,EUS-guided pancreaticogastrostomy(PGS)was applied using a fully covered,self-expandable,10-mm diameter metallic stent.The treatment resolved the case and the patient experienced no adverse events.EUS-guided PGS with a regular biliary fully covered,self-expandable metallic stent effectively and safely treated pancreatictype pain in chronic pancreatitis.

Efficacy of uncovered self-expandable metallic stent for colorectal obstruction by extracolonic malignancy

BACKGROUND Self-expandable metallic stent(SEMS)is widely used for malignant colorectal obstruction.Recently,SEMS has been used for palliative option for colorectal obstruction caused by extracolonic malignancy(ECM).AIM To evaluate the efficacy of SEMS for colorectal obstruction caused by ECM,and to identify the factors associated with stent occlusion.METHODS Seventy-two patients who were treated with uncovered SEMS insertion for malignant colorectal obstructions caused by colorectal metastasis or peritoneal seeding of ECM at Samsung Medical Center between April 2012 to March 2016 were enrolled.We analyzed technical and clinical outcomes of stent insertion,the factors associated with stent occlusion and long term outcomes after stent insertion.RESULTS Technical success rate was determined as 90.3%with a clinical success rate of 87.7%.Stent occlusion developed in 28.1%,with a median duration of 51 d.Further,81.3%with stent occlusion could be treated with secondary stent insertion.Clinical failure was observed to be related to the male sex(P=0.020)and right colon obstruction(P=0.017).Stent length≤10 cm was found to be associated with stent occlusion(P=0.003).Median survival time after stent insertion was 4.7 mo and 40.4%were able to receive their oncological treatments after stent insertion without surgery.CONCLUSION Uncovered SEMS is effective for the treatment of colorectal obstruction caused by ECM,considering life expectancy of patients with ECM.

Self-expandable metal stents for achalasia: Thinking out of the box!

Achalasia is a primary motor disorder of the esophagus diagnosed manometrically in the clinical setting of dysphagia to both solids and liquids. Currently established treatment options include pneumatic dilation, laparoscopic Heller myotomy, botulinum toxin injection performed endoscopically, oral agents that relax the lower esophageal sphincter and esophagectomy for refractory, end-stage disease. Despite their effectiveness, a significant proportion of patients eventually relapses and needs retreatment. In this setting, several new techniques are under investigation promising future enrichment of our therapeutic armamentarium for achalasic patients. Among them, peroral endoscopic myotomy and selfexpandable metal stents placed across the gastroesophageal junction represent the most encouraging modalities, as initial studies assessing their efficacy and safety indicate. This review highlights the role of selfexpandable metal stents in the management of patients with achalasia. Their possible position in the therapeutic algorithm of achalasia along with established and novel techniques is also assessed. Finally, the need for large prospective randomized trials is underlined in order to elucidate the numerous relevant issues.

Endoscopic transpapillary gallbladder drainage with replacement of a covered self-expandable metal stent

Endoscopic self-expandable metal stent (SEMS) placement has become a standard palliative therapy for pa- tients with malignant biliary obstruction. Acute cholecystitis after SEMS placement is a serious complication. We report a patient with an acute cholecystitis after covered SEMS placement, who was managed successfully with endoscopic transpapillary gallbladder drainage (ETGBD) and replacement of the covered SEMS. An 85-year-old man with pancreatic cancer suffered from acute cholecystitis after covered SEMS placement. It was impossible to perform percutaneous transhepatic gallbladder drainage. After removal of the covered SEMS with a snare, a 7Fr double pigtail stent was placed between the gallbladder and duodenum, subsequently followed by another covered SEMS insertion into the common bile duct beside the gallbladder stent. The cholecystitis improved immediately after ETGBD. ETGBD with replacement of the covered SEMS thus proved to be effective for treatment of patients with acute cholecystitis after covered SEMS placement.

Case of arterial hemorrhage after endoscopic papillary large balloon dilation for choledocholithiases using a covered self-expandable metallic stent

A 78-year-old male was admitted to our hospital because of choledocholithiasis.ERC demonstrated choledocholithiases with a maximum diameter of 13 mm, and we performed endoscopic papillary large balloon dilation(EPLBD) with a size of 15 mm.Immediately following the balloon deflation, spurting hemorrhage occurred from the orifice of the duodenal papilla.Although we performed endoscopic hemostasis by compressing the bleeding point with the large balloon catheter, we could not achieve hemostasis.Therefore, we placed a 10 mm fully covered selfexpandable metallic stent(SEMS) across the duodenal papilla, and the hemorrhage stopped immediately.After 1 wk of SEMS placement, duodenal endoscopy revealed ulcerative lesions in both the orifice of the duodenal papilla and the lower bile duct.A direct peroral cholangioscopy using an ultra-slim upper endoscope revealed a visible vessel with a longitudinal mucosal tear in the ulceration of the lower bile duct.We believe that the mucosal tear and subsequent ruptured vessel were caused by the EPLBD procedure.

Complications of airway self-expandable metallic stent in benign airway diseases

Objectives: To present the complications of Ultraflex Self-Expandable Metallic Stents (SEMSs) applied in patients with benign tracheobronchial diseases. Methods: Eighty patients received 124 SEMSs were retrospectively reviewed in a tertiary hospital. Results: The baseline characteristics of patients received SEMS implantation including age (mean + standard deviation: 62.5 + 14.8 years), gender (male, 60.5%), smoking (46.8%), forced expiratory volume in first one second (FEV1) (mean + standard deviation, 0.92 +0.41 L/s), follow-up days after SEMS implantation (median (interquartile range);457 (131 - 897)) and covered SEMS (33.9%) were listed. Symptoms improved after SEMS implantation among 95 patients (76.6%). Time to complications developed was 236 (median;interquartile range, 59 - 672) days. The overall complication rate was 41.9% after SEMS implantation. The complications included SEMS migration (6.5%), granuloma (19.3%) and SEMS fracture (16.1%). Successful management rates of SEMS migration, granuloma and SEMS fracture were up to 100%, 83.3%, and 85% respectively. Conclusions: Patients received SEMS implantation due to benign conditions had poor lung function and were old. The complication rate in patients with benign conditions was high after longer follow-up period, however, successful management achieved in most patients with complications.

Endoscopic therapy using a self-expandable metallic stent with an anti-migration system for postorthotopic liver transplantation anastomotic biliary stricture

BACKGROUND Endoscopic therapy using multiple plastic stents(MPSs)is the standard therapy for postorthotopic liver transplantation(p-OLT)anastomotic biliary stricture(ABS).However,this approach demands repeated procedures.Recent studies us-ing fully covered self-expandable metallic stents(FCSEMS)have shown en-couraging results,but migration occurs in 10%to 40%of cases.The objective of this retrospective study was to evaluate the efficacy of endoscopic treatment using FCSEMS with an anti-migration system(Am-FCSEMS)in patients with p-OLT ABS.AIM To evaluate the efficacy of endoscopic treatment using an Am-FCSEMS in patients with p-OLT ABS.METHODS This study was conducted in a private tertiary care centre in S?o Paulo,Brazil and was approved by our institution's Human Research Committee.From April 2018 to October 2020,regardless of previous endoscopic treatment(MPS or FCSEMS),17 patients with p-OLT ABS and indications for endoscopic therapy were included in this study.The exclusion criteria were pregnancy,nonanastomotic biliary or hilar stricture,hepatic artery stenosis/thrombosis,isolated biliary fistulae,a distance shorter than 2 cm from the stricture to the hepatic hilum,and patient refusal.The primary endpoint was the efficacy of p-OLT ABS endoscopic treatment using an Am-FCSEMS that re-mained in place for a 12-mo period.Biliary sphincterotomy was performed in patients with native papilla,and an Am-FCSEMS(10 mm in final diameter and 60 or 80 mm in length)was placed(Hanarostent TM MI Tech,Co).Balloon stricture dilation was performed only if necessary to introduce the stent.RESULTS Three patients were excluded due to loss to follow-up before stent removal.Among the 14 patients included and followed,7 were women,and the average age was 56 years(range:28-76).The average period of Am-FCSEMS placement was 362±109 d.Technical success occurred in all 14 patients(100%).There were no cases of distal stent migration.Complete resolution of the stricture occurred in 13/14 patients(92.85%).Adverse events occurred in 3/14 patients(21.42%):2 patients with mild acute pancreatitis(14.28%)and 1 patient(7.14%)with stent dysfunction(occlusion by biliary sludge and stones,which was treated endoscopically without the need for stent removal).No deaths occurred related to therapy.All stents were removed using foreign body forceps or snares without difficulty.After Am-FCSEMS removal,all 13 patients who had ABS resolution were followed-up for an average of 411±172 d,and there was no stricture recurrence or need for further endoscopic therapy.CONCLUSION In this retrospective study,endoscopy therapy using an Am-FCSEMS for p-OLT ABS was safe and effective,with a high stricture re-solution rate that was probably due to the absence of stent migration.

Angle of covered self-expandable metallic stents after placement is a risk factor for recurrent biliary obstruction

BACKGROUND Studies have shown that covered self-expandable metallic stents(CSEMS)with a low axial forces after placement can cause early recurrent biliary obstruction(RBO)due to precipitating sludge formation.AIM To ascertain whether the angle of CSEMS after placement is a risk factor for RBO in unresectable distal malignant biliary obstruction(MBO).METHODS Between January 2010 and March 2019,261 consecutive patients underwent selfexpandable metallic stent insertion by endoscopic retrograde cholangiopancreatography at our facility,and 87 patients were included in this study.We evaluated the risk factors for RBO,including the angle of CSEMS after placement as the primary outcome.We measured the obtuse angle of CSEMS after placement on an abdominal radiograph using the SYNAPSE PACS system.We also evaluated technical and functional success,adverse events,time to RBO(TRBO),non-RBO rate,survival time,cause of RBO,and reintervention procedure as secondary outcomes.RESULTS We divided the patients into two cohorts based on the presence or absence of RBO.The angle of CSEMS after placement(per 1°and per 10°)was evaluated using the multivariate Cox proportional hazard analysis,which was an independent risk factor for RBO in unresectable distal MBO[hazard ratio,0.97 and 0.71;95%confidence interval(CI):0.94-0.99 and 0.54-0.92;P=0.01 and 0.01,respectively].For early diagnosis of RBO,the cut-off value of the angle of CSEMS after placement using the receiver operating characteristic curve was 130°[sensitivity,50.0%;specificity 85.5%;area under the curve 0.70(95%CI:0.57-0.84)].TRBO in the<130°angle group was significantly shorter than that in the≥130°angle group(P<0.01).CONCLUSION This study suggests that the angle of the CSEMS after placement for unresectable distal MBO is a risk factor for RBO.These novel results provide pertinent information for future stent management.

Development of a biliary multi-hole self-expandable metallic stent for bile tract diseases: A case report

BACKGROUND Uncovered stents used for malignant obstructions in the biliary tree, especially in the hilar area, are prone to obstruction by tumor ingrowths. In comparison, however, covered stents may block bile duct branches and are at risk of migration. We have developed a multi-hole self-expandable metallic stent (MHSEMS), with a hole in each cell, to prevent the obstruction of bile duct branches. In addition, the holes may prevent migration due to small ingrowths by reducing the tension of the membrane. CASE SUMMARY MHSEMS were placed in five patients with a malignant obstruction and one with post-endoscopic sphincterotomy bleeding. Each MHSEMS was successfully deployed in all cases. Patients showed no complications. Two cases were reviewed. Case 1: A 74-year-old male presented with jaundice and was diagnosed with a sigmoid colon cancer and giant liver metastases in the right liver lobe. A MHSEMS was placed in the left bile duct. The jaundice improved and peroral cholangioscopy was performed. Case 2: A 90-year-old female was admitted to hospital for jaundice and diagnosed with cholangiocarcinoma. A MHSEMS was placed in the left bile duct but after 8 months the stent became obstructed by tumor ingrowth. We treated the patient by ablation therapy. A silicone cover separated the internal bile duct from the surrounding tissue, protecting the latter from thermal injury during treatment by endobiliary ablation of the reobstruction. CONCLUSION A MHSEMS is a new choice of stent for biliary tract diseases.