Role of balloon enteroscopy for obscure gastrointestinal bleeding in those with surgically altered anatomy: A systematic review

BACKGROUND Obscure gastrointestinal(GI)bleeding is defined as persistent bleeding despite negative evaluation with both esophagogastroduodenoscopy and colonoscopy and can be secondary to small intestinal pathology.Standard endoscopy as well as push endoscopy can be a challenge in those with altered anatomy given inaccessible areas as well as perforation risk.Single and double balloon enteroscopy can be warranted in this patient population in instances of obscure GI bleed.AIM To assess the safety and diagnostic efficacy of balloon enteroscopy for obscure GI bleeding in patients with surgically altered anatomy.METHODS A search was conducted through PubMed,MEDLINE,Google Scholar,Scopus,and Embase with the key words“enteroscopy,”“obscure bleeding,”and“altered anatomy,”to identify relevant articles in English with no restricted time frame.A search within the Reference Citation Analysis database was conducted to ensure inclusion of the latest high impact articles.Study types included in the review were prospective and retrospective reviews,case series,and case reports.The reference lists of these papers were also reviewed to find further papers that were applicable.The authors extracted the data from the studies that fit inclusion criteria.Data of interest included type of study,type of procedure,and type of altered anatomy,as well as the number of patients with any diagnostic or therapeutic intervention.Data was also recorded on procedure tolerance and complications.The data was analyzed with descriptive statistics.RESULTS Our literature search yielded 14 studies that were included.There were 68 procedures performed with 61 unique patients subjected to these procedures.Forty-four(65%)of the procedures were double balloon,21(31%)were single balloon,and 3(4%)were classified as through the scope balloon assisted.The most common altered anatomy types included Gastric Bypass Roux-en-Y,Pylorus Sparing Whipple,Orthotopic Liver Transplantation with Roux-en-Y,and Gastrojejunostomy Roux-en-Y.The procedures were successfully performed in each patient.There were 5(7%)procedures that were complicated by perforation.Amongst the available data,the diagnostic yield was 48/59(81%)and a therapeutic yield of 39/59(66%).One patient was recommended surgical revision of their altered anatomy following enteroscopy.CONCLUSION Balloon enteroscopy is a useful diagnostic modality in investigating obscure GI bleeding within those with surgically altered anatomy;however,precautions must be taken as this population may have increased perforation risk.

A meta-analysis of the yield of capsule endoscopy compared to double-balloon enteroscopy in patients with small bowel diseases

AIM:To compare the diagnostic yield of capsule endoscopy (CE) with that of double-balloon enteroscopy (DBE). METHODS:Pubmed,Embase,Elsevier ScienceDirect,the China Academic Journals Full-text Database,and Cochrane Controlled Trials Register were searched for the trials comparing the yield of CE with that of DBE. Outcome measure was odds ratio (OR) of the yield. Fixed or random model method was used for data analysis. RESULTS:Eight studies (n = 277) which prospectively compared the yield of CE and DBE were collected. The results of meta-analysis indicated that there was no difference between the yield of CE and DBE 170/277 vs 156/277,OR 1.21 (95% CI:0.64-2.29). Based on sub analysis,the yield of CE was significantly higher than that of double-balloon enteroscopy without combination of oral and anal insertion approaches 137/219 vs 110/219,OR 1.67 (95% CI:1.14-2.44),P < 0.01),but not superior to the yield of DBE with combination of the two insertion approaches 26/48 vs 37/48,OR 0.33 (95% CI:0.05-2.21),P > 0.05). A focused meta-analysis of the fully published articles concerning obscure GI bleeding was also performed and showed similar results wherein the yield of CE was significantly higher than that of DBE without combination of oral and anal insertion approaches 118/191 vs 96/191,fixed model:OR 1.61 (95% CI:1.07-2.43),P < 0.05) and the yield of CE was significantly lower than that of DBE by oral and anal combinatory approaches 11/24 vs 21/24,fixed model:OR 0.12 (95% CI:0.03-0.52),P < 0.01). CONCLUSION:With combination of oral and anal approaches,the yield of DBE might be at least as high asthat of CE. Decisions made regarding the initial approach should depend on patient's physical status,technology availability,patient's preferences,and potential for therapeutic endoscopy.

Double balloon enteroscopy in children:Diagnosis,treatment,and safety

AIM:To assess the feasibility and utility of double balloon enteroscopy(DBE)in the management of small bowel diseases in children. METHODS:Fourteen patients(10 males)with a median age of 12.9 years(range 8.1-16.7)underwent DBE; 5 for Peutz-Jeghers syndrome(PJ syndrome),2 for chronic abdominal pain,4 for obscure gastrointestinal (GI)bleeding,2 with angiomatous malformations(1 blue rubber bleb nevus syndrome)having persistent GI bleeding,and 1 with Cowden's syndrome with multiple polyps and previous intussusception.Eleven procedures were performed under general anesthesia and 3 with deep sedation. RESULTS:The entire small bowel was examined in 6 patients,and a length between 200 cm and 320 cm distal to pylorus in the remaining 8.Seven patients had both antegrade(trans-oral)and retrograde(transanal and via ileostomy)examinations.One patient underwent DBE with planned laparoscopic assistance.The remaining 6 had trans-oral examination only.The median examination time was 118 min(range 95-195). No complications were encountered.Polyps were detected and successfully removed in all 5 patients with PJ syndrome,in a patient with tubulo-villous adenoma of the duodenum,in a patient with significant anemia and occult bleeding,and in a patient with Cowden's syndrome.A diagnosis was made in a patient with multiple angiomata not amenable to endotherapy,and in 1 with a discrete angioma which was treated with argon plasma coagulation.The source of bleeding was identified in a further patient with varices.DBE was normal or revealed minor mucosal friability in the remaining 3 patients.Hence a diagnostic yield of 11/14 with therapeutic success in 9/14 was achieved. CONCLUSION:Double balloon enteroscopy can be a useful diagnostic and therapeutic tool for small bowel disease in children,allowing endo-therapeutic intervention beyond the reach of the conventional endoscope.

Evaluation of “top-down” treatment of early Crohn's disease by double balloon enteroscopy

AIM: To assess &#x0201c;top-down&#x0201d; treatment for deep remission of early moderate to severe Crohn&#x02019;s disease (CD) by double balloon enteroscopy.

Double balloon enteroscopy examinations in general anesthesia

AIM:To demonstrate that the double balloon enteroscopy(DBE) can be safely performed in general anesthesia with intubation.METHODS:We performed a retrospective examination between August 2005 and November 2008 amongpatients receiving intubation narcosis due to DBE examination.The patients were grouped based on sex,age and physical status.Anesthesia records includedduration of anesthesia,quantity of medication usedand anesthesia-related complications.We determinedthe frequency of complications in the different groupsand their relation with the quantity of medication usedand the duration of anesthesia.RESULTS:We compiled data for 108 cases of general anesthesia with intubation.We did not observeany permanent anesthesia-related complications;themost frequent side effects of anesthesia were hypo-tension(30.55%),desaturation(21.29%),and apnea(17.59%).These complications were significantly more frequent among patients with multiple additional diseases [hypotension(23.1% vs 76.9%,P = 0.005),desaturation(12.3% vs 69.2%,P < 0.001) and apnea(7.7% vs 53.8%,P = 0.001)],however,their incidence was not proportional to the quantity of medication used or the duration of anesthesia.CONCLUSION:General anesthesia with intubation is definitely a viable option among DBE methods.It is highly recommended in patients with multiple additional diseases.

Double balloon enteroscopy in the old: Experience from China

AIM: To evaluate the safety, efficacy and management of double balloon enteroscopy (DBE) carried out in those aged individuals with suspicious small intestine diseases. METHODS: DBE is a wonderful invention of the past decade and is widely used as an examination tool for the gastrointestinal tract. From January 2003 to July 2011, data from patients who were ≥ 65 years old and underwent DBE examination in the Nanfang Hospital were included in a retrospective analysis.RESULTS: Fifty-nine individuals were found and subsequently analyzed. The mean age was 69.63 ± 3.89 years (range 65-84), 34 were males. Indications for DBE were melena/hematochezia (36 cases), abdominal pain (15 cases), diarrhea (3 cases), stool change (1 case), weight loss (1 case), vomiting (2 cases), and debilitation (1 case). The average duration of symptoms was 33.34 ± 64.24 mo. Twenty-seven patients suffered from age-related diseases. Severe complications were not found during and after DBE. Comparison between systolic and diastolic blood pressure before and after DBE was statistically significant (mean ± SD, P < 0.01, P < 0.05, respectively). Small bowel pathologies were found by DBE in 35 patients, definite diagnoses were made in 31 cases, and detection rate and diagnostic yield for DBE were 68.6% and 60.8%, respectively. CONCLUSION: DBE is a safe and effective method for gastrointestinal examination in the aged population. Aging alone is not a risk factor for elderly patients with suspicious gastrointestinal diseases and thorough preparation prior to the DBE procedure should be made for individuals with multiple diseases especially cardiopulmonary disorders.

Evidences supporting the vascular etiology of post-double balloon enteroscopy pancreatitis: Study in porcine model

Double balloon enteroscopy(DBE) is an endoscopic technique broadly used to diagnose and treat small bowel diseases. Among the associated complications of the oral DBE, post-procedure pancreatitis has taken the most attention due to its gravity and the thought that it might be associated to the technique itself and anatomical features of the pancreas. However, as the etiology has not been clarified yet, this paper aims to review the published literature and adds new results from a porcine animal model. Biochemical markers, histological sections and the vascular perfusion of the pancreas were monitored in the pig during DBE practice. A reduced perfusion of the pancreas and bowel, the presence of defined hypoxic areas and disseminated necrotic zones were found in the pancreatic tissue of pigs. All these evidences contribute to support a vascular distress as the most likely etiology of the post-DBE pancreatitis.

Evaluation of the diagnostic and therapeutic utility of retrograde through-the-scope balloon enteroscopy and single-balloon enteroscopy

BACKGROUND Retrograde single balloon enteroscopy(SBE)is a minimally invasive procedure which is less frequently performed compared with antegrade SBE.There are few studies on the retrograde through-the-scope enteroscopy(TTSE),a novel technique for evaluation of the small bowel.AIM To compare the clinical utility and safety of retrograde TTSE with retrograde SBE.METHODS Clinical data and complications of retrograde TTSE(2014-2018)and retrograde SBE(2011-2018)performed in a community hospital were reviewed and presented as mean±SD or frequency(%)and compared using proper statistical tests.Technical success was defined as insertion of the enteroscope>20 cm beyond ileocecal valve.RESULTS Data obtained from 54 retrograde SBE in 49 patients and 27 retrograde TTSE in 26 patients were studied.The most common indication for retrograde enteroscopy was iron deficiency anemia(41 patients)followed by gastrointestinal bleeding(37 patients),and chronic diarrhea(7 patients).The duration of retrograde SBE procedure(91.9±34.2 min)was significantly longer compared with retrograde TTSE(70.5±30.7 min)(P=0.04).Technical success was comparable in TTSE[23/27(85.2%)]and SBE[41/54(75.9%)(P=0.33)].The mean depth of insertion beyond the ileocecal valve in retrograde SBE(92.5±70.0 cm)tended to be longer compared with retrograde TTSE(64.6±49.0 cm)(P=0.08).No complication was observed in this study.CONCLUSION Both retrograde TTSE and retrograde SBE are feasible and safe.Retrograde TTSE takes a shorter time and has a comparable technical success with SBE.TTSE has a lower capacity of small bowel insertion.

Clinical profile,diagnostic yield,and procedural outcomes of single balloon enteroscopy:A tertiary care hospital experience

BACKGROUND Single balloon enteroscopy(SBE)allows ease of access for small bowel visualization and has multiple diagnostic and therapeutic indications.It provides the advantage of performing various therapeutic interventions alongside the diagnostic procedure.SBE has also been considered a relatively safe procedure with no major complications.AIM To investigate the indications,safety,and clinical yield of SBE,and determine its effect on disease outcome.METHODS A retrospective,descriptive study was conducted at a tertiary care hospital in Karachi,Pakistan.Medical records of 56 adult patients(≥18 years)who underwent SBE between July 2013 and December 2021 were reviewed and data were collected using a structured proforma.A descriptive analysis of the variables was performed using Statistical Package of Social Sciences Version 19.Results are reported as the mean±SD for quantitative variables and numbers and percentages for qualitative variables.Missing data are reported as unknown.RESULTS A total of 56 patients who underwent 61 SBE procedures were included.The mean age was 50.93±16.16 years,with 53.6%of them being males.Hypertension(39.3%)and diabetes mellitus(25.0%)were the most common pre-existing comorbidities.Obscure gastrointestinal bleed(39.3%)was the most common indication for enteroscopy,followed by chronic diarrhea(19.7%)and unexplained anemia(16.4%).The majority of procedures were performed in the endoscopy suite(90.2%)under monitored anaesthesia care(93.4%).Most procedures were diagnostic(91.8%)and completed without complications(95.1%).The depth of examination ranged from 95 cm to 500 cm with a mean of 282.05±90.04 cm.The most common findings were inflammation and ulcerations(29.5%),followed by masses(19.7%)and vascular malformations(14.8%).As a result of the findings,a new diagnosis was made in 47.5%of the cases and a previous one was ruled out in 24.6%of them;65.6%of the cases had a change in management.CONCLUSION SBE is a suitable modality for investigating diseases in the small bowel.It is shown to be technically efficient and reasonably safe and is associated with high diagnostic and therapeutic yield.

ConservativeapproachinPeutz-JeghersSyndrome:Single-balloon enteroscopyandsmallbowelpolypectomy

AIM: To assess the usefulness of the balloon assisted enteroscopy in preventing surgical intervention in pa-tients with Peutz-Jeghers syndrome (PJS) having a small bowel large polyps. METHODS: Seven consecutive asymptomatic pts(age 15-38 years) with PJS have been collected; six under-went polypectomy using single balloon enteroscopy(Olympus SIF Q180) with antegrade approach using push and pull technique. SBE system consists of the SIF-Q180 enteroscope, an overtube balloon control unit(OBCU Olympus Balloon Control Unit) and a dispos-able silicone splinting tube with balloon(ST-SB1). All procedures were performed under general anesthesia. Previously all pts received wireless capsule endos-copy(WCE). Prophylactic polypectomy was reservedmainly in pts who had polyps > 15 mm in diameter. The balloon is inflated and deflated by a balloon control unit with a safety pressure setting range from-6.0 kPa to +5.4 kPa. Informed consent has been obtained from pts or parents for each procedure.RESULTS: Six pts underwent polypectomy of small bowel polyps; in 5 pts a large polyp > 15 mm(range 20-50 mm in diameter) was resected; in 1 patient with WCE negative, SBE was performed for previous surgi-cal resection of gastrointestinal stromal tumors. In 2 pts endoscopic clips were placed due to a polypectomy. No surgical complication have been reported. SBE with resection of small bowel large polyps in PJS pts was useful to avoid gastrointestinal bleeding and emergency laparotomy due to intestinal intussuscep-tions. No gastrointestinal tumors were found in sub-sequent enteroscopic surveillance in all seven pts. In order surveillance, all pts received WCE, upper en-doscopy, ileocolonoscopy every 2 years. No pts had extraintestinal malignant lesions. SBE was performed when WCE was positive for significant polyps(> 15 mm).CONCLUSION: The effective of prophylactic polyp-ectomy of small bowel large polyps(> 15 mm) could be the first line treatment for conservative approach in management of PJS patients.

Two case reports of acute upper gastrointestinal bleeding from duodenal ulcers after Roux-en-Y gastric bypass surgery: Endoscopic diagnosis and therapy by single balloon or push enteroscopy after missed diagnosis by standard esophagogastroduodenoscopy

The diagnosis and opportunity for endoscopic therapy of gastric or duodenal lesions may be missed at esophagogastroduodenoscopy(EGD) because of technical difficulty in intubating at EGD the postoperatively excluded stomach and proximal duodenum in patients status post Roux-en-Y gastric bypass(RYGB). Two cases are reported of acute upper gastrointestinal bleeding 10 or 11 years status postRYGB, performed for morbid obesity, in which the EGD was non-diagnostic due to failure to intubate the excluded stomach and proximal duodenum, whereas subsequent push enteroscopy or single balloon enteroscopy were diagnostic and revealed 4-cm-wide or 5-mm-wide bulbar ulcers and even permitted application of endoscopic therapy. These case reports suggest consideration of push enteroscopy, or single balloon enteroscopy, where available, in the endoscopic evaluation of acute UGI bleeding in patients status post RYGB surgery when the EGD was non-diagnostic because of failure to intubate these excluded segments.

Double-balloon-enteroscopy-based endoscopic retrograde cholangiopancreatography in post-surgical patients

AIM: To evaluate double balloon enteroscopy (DBE) in post-surgical patients to perform endoscopic retrograde cholangiopancreatography (ERCP) and interventions. METHODS: In 37 post-surgical patients, a stepwise approach was performed to reach normal papilla or enteral anastomoses of the biliary tract/pancreas. When conventional endoscopy failed, DBE-based ERCP was performed and standard parameters for DBE, ERCP and interventions were recorded. RESULTS: Push-enteroscopy (overall, 16 procedures) reached enteral anastomoses only in six out of 37 post-surgical patients (16.2%). DBE achieved a high rate of luminal access to the biliary tract in 23 of the remaining 31 patients (74.1%) and to the pancreatic duct (three patients). Among all DBE-based ERCPs (86 procedures), 21/23 patients (91.3%) were successfully treated. Interventions included ostium incision or papillotomy in 6/23 (26%) and 7/23 patients (30.4%), respectively. Biliary endoprosthesis insertion and regular exchange was achieved in 17/23 (73.9%) and 7/23 patients (30.4%), respectively. Furthermore, bile duct stone extraction as well as ostium and papillary dilation were performed in 5/23 (21.7%) and 3/23 patients (13.0%), respectively. Complications during DBE-based procedures were bleeding (1.1%), perforation (2.3%) and pancreatitis (2.3%), and minor complications occurred in up to 19.1%. CONCLUSION: The appropriate use of DBE yields a high rate of luminal access to papilla or enteral anastomoses in more than two-thirds of post-surgical patients, allowing important successful endoscopic therapeutic interventions.

Is enteroscopy necessary for diagnosis of celiac disease?

Celiac disease （CD） is an autoimmune inflammatory disease of the small intestine as a result of reaction to wheat protein, gluten. Exclusion of dietary gluten is the mainstay of the treatment that necessitates a precise diagnosis of the disease. Serological screen ing may aid in identifying patients with suspected CD, which should be confirmed by intestinal biopsy. It has been shown that duodenal biopsies are good for de- tection of the disease in most patients. However, there is a group of patients with positive serology and incon- clusive pathology. As a result of the widespread use of serology, many patients with equivocal findings grow quickly. Unfortunately current endoscopic methods can only diagnose villous atrophy, which can be present in the later grades of disease （i.e., Marsh m）. To diag- nose CD correctly, going deeper in the intestine may be necessary. Enteroscopy can reveal changes in CD in the intestinal mucosa in 10%-17% of cases that have negative histology at initial workup. Invasiveness of the method limits its use. Capsule endoscopy may be a good substitute for enteroscopy. However, both tech- niques should be reserved for patients with suspected diagnosis of complications. This paper reviews the cur- rent literature in terms of the value of enteroscopy for diagnosis of CD.

Endoscopic management of difficult common bile duct stones:Where are we now?A comprehensive review

Endoscopic management for difficult common bile duct(CBD)stones still presents a challenge for several reasons,including anatomic anomalies,patients’individual conditions and stone features.In recent years,variable methods have emerged that have attributed to higher stone removal success rates,reduced cost and lower adverse events.In this review,we outline a stepwise approach in CBD stone management.As first line therapy,endoscopic sphincterotomy and large balloon dilation are recommended,due to a 30%-50%reduction of the use of mechanical lithotripsy.On the other hand,cholangioscopy-assisted lithotripsy has been increasingly reported as an effective and safe alternative technique to mechanical lithotripsy but remains to be reserved in special settings due to limited large-scale evidence.As discussed,findings suggest that management needs to be tailored to the patient’s characteristics and anatomical conditions.Furthermore,we evaluate the management of CBD stones in various surgical altered anatomy(Billroth II,Roux-en-Y and Roux-en-Y gastric bypass).Moreover,we could conclude that cholangioscopy-assisted lithotripsy needs to be evaluated for primary use,rather than following a failed management option.In addition,we discuss the importance of dissecting other techniques,such as the primary use of interventional endoscopic ultrasound for the management of CBD stones when other techniques have failed.In conclusion,we recognize that endoscopic sphincterotomy and large balloon dilation,mechanical lithotripsy and intraductal lithotripsy substantiate an indication to the management of difficult CBD stones,but emerging techniques are in rapid evolution with encouraging results.

Update on imaging of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome(PJS) is a rare, autosomal dominant disease linked to a mutation of the STK 11 gene and is characterized by the development of benign hamartomatous polyps in the gastrointestinal tract in association with a hyperpigmentation on the lips and oral mucosa. Patients affected by PJS have an increased risk of developing gastrointestinal and extra-digestive cancer. Malignancy most commonly occurs in the smallbowel. Extra-intestinal malignancies are mostly breast cancer and gynecological tumors or, to a lesser extent, pancreatic cancer. These polyps are also at risk of acute gastrointestinal bleeding, intussusception and bowel obstruction. Recent guidelines recommend regular smallbowel surveillance to reduce these risks associated with PJS. Small-bowel surveillance allows for the detection of large polyps and the further referral of selected PJS patients for endoscopic enteroscopy or surgery. Video capsule endoscopy, double balloon pushed enteroscopy,multidetector computed tomography and magnetic resonance enteroclysis or enterography, all of which are relatively new techniques, have an important role in the management of patients suffering from PJS. This review illustrates the pathological, clinical and imaging features of small-bowel abnormalities as well as the role and performance of the most recent imaging modalities for the detection and follow-up of PJS patients.

Treatment of gastrointestinal bleeding in left ventricular assist devices:A comprehensive review

Left ventricular assist devices(LVAD)are increasingly become common as life prolonging therapy in patients with advanced heart failure.Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps.Unfortunately,continuous flow LVADs are fraught with complications such as gastrointestinal(GI)bleeding that are primarily attributed to the formation of arteriovenous malformations.With frequent GI bleeding,antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events.Small bowel bleeds account for 15%as the source and patients often undergo multiple endoscopic procedures.Treatment strategies include resuscitative measures and endoscopic therapies.Medical treatment is with octreotide.Novel treatment options include thalidomide,angiotensin converting enzyme inhibitors/angiotensinⅡreceptor blockers,estrogen-based hormonal therapies,doxycycline,desmopressin and bevacizumab.Current research has explored the mechanism of frequent GI bleeds in this population,including destruction of von Willebrand factor,upregulation of tissue factor,vascular endothelial growth factor,tumor necrosis factor-α,tumor growth factor-β,and angiopoetin-2,and downregulation of angiopoetin-1.In addition,healthcare resource utilization is only increasing in this patient population with higher admissions,readmissions,blood product utilization,and endoscopy.While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages,these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years.

Assessment of multi-modality evaluations of obscure gastrointestinal bleeding

AIMTo determine the frequency of bleeding source detection in patients with obscure gastrointestinal bleeding (OGIB) who underwent double balloon enteroscopy (DBE) after pre-procedure imaging [multiphase computed tomography enterography (MPCTE), video capsule endoscopy (VCE), or both] and assess the impact of imaging on DBE diagnostic yield.METHODSRetrospective cohort study using a prospectively maintained database of all adult patients presenting with OGIB who underwent DBE from September 1st, 2002 to June 30th, 2013 at a single tertiary center.RESULTSFour hundred and ninety five patients (52% females; median age 68 years) underwent DBE for OGIB. AVCE and/or MPCTE performed within 1 year prior to DBE (in 441 patients) increased the diagnostic yield of DBE (67.1% with preceding imaging vs 59.5% without). Using DBE as the gold standard, VCE and MPCTE had a diagnostic yield of 72.7% and 32.5% respectively. There were no increased odds of finding a bleeding site at DBE compared to VCE (OR = 1.3, P = 0.150). There were increased odds of finding a bleeding site at DBE compared to MPCTE (OR = 5.9, P < 0.001). In inpatients with overt OGIB, diagnostic yield of DBE was not affected by preceding imaging.CONCLUSIONDBE is a safe and well-tolerated procedure for the diagnosis and treatment of OGIB, with a diagnostic yield that may be increased after obtaining a preceding VCE or MPCTE. However, inpatients with active ongoing bleeding may benefit from proceeding directly to antegrade DBE.

Strategies to manage the difficult colonoscopy

During endoscopy,an endoscopist is inevitably faced with the occasional“difficult colonoscopy,”in which the endoscopist finds it challenging to advance the endoscope to the cecum.Beyond optimization of technique,with minimized looping,minimal insufflation,sufficient sedation,and abdominal splinting when needed,sometimes additional tools may be needed.In this review,we cover available techniques and technologies to help navigate the difficult colonoscopy,including the ultrathin colonoscope,rigidizing overtube,balloon-assisted colonoscopy and the abdominal compression device.