push and sonde enteroscopy were widely used for small - bowel endoscopy prior to the development of double - balloon enteroscopy ( dbe ) . however , due to the insufficient depth of intubation into the small bowel and the high rate of complications with push and sonde enteroscopy , new techniques that overcame these issues were needed . moreover
yamamoto et al .   was the first to develop and use dbe in 2001 .
based on the length , channel width , and clinical use , dbe is categorized into three types : diagnostic , therapeutic , and biliary dbe .
balloon enteroscopy can be used for all small - bowel pathologies including ileus and obstruction .
dbe is also very useful for endoscopic retrograde cholangiopancreatography ( ercp ) in cases with postsurgical anatomy ( roux - en - y gastric bypass or other types of gastric bypass surgery ) and cases of difficult colonoscopy .
the cecal intubation rate was 97% in cases of unsuccessful conventional colonoscopy , and the success rate of dbe - assisted ercp was 60% to 100% .
dbe should not be used in patients who are at risk for impaired general condition and perforation .
a watery diet and bowel cleansing should be implemented 1 day before the procedure to ensure a successful outcome .
the most important advantage of dbe is the applicability of therapeutic interventions during the procedure .
however , its disadvantages include a long learning curve , long processing time , and the requirement for patient sedation .
the average processing time was 92.437.6 minutes , and this period was significantly longer in the first 10 patients ( 109.144.6 minutes ; p<0.005 ) .
the total rate of diagnosis has been reported as 43% , and the cause of bleeding was unidentified in 51% cases . however , in a study by yamamoto et al . , who improved the technique , the mean procedure duration was 123 minutes and the oral , rectal , and all parts of small bowel could be investigated in 86% of patients over 178 enteroscopy procedures . in studies reported from europe ( 70 dbe procedures in 53 patients ) , the rate of observation of the entire small bowel was 8% and the average procedure time was 72 minutes . in the study conducted by fukumoto et al . , the rate of observation of the entire small bowel was higher , although the difference was not statistically significant .
the most important advantage of dbe is that it allows therapeutic approaches such as argon plasma coagulation ( apc ) , polypectomy ( fig .
1 ) , dilatation , foreign body removal , and stent placement during the procedure . may et al .  
reported that dbe procedures were performed in 60% of 353 patients who were admitted due to bleeding .
dbe was found to be diagnostically and therapeutically beneficial in 75% and 67% of these cases , respectively .
although the complication rate for dbe is 3.4% , this rate is reported to be 10.8% in cases of polypectomy ( bleeding - perforation ) and 0.9% in cases of apc . in a multicenter study that included 2,362 dbe procedures , 709 cases of pancreatitis , five cases of perforation ( three apc and two dilatation ) , and 18 cases of bleeding ( 13 after polypectomy )
although the complication rate is greater in patients undergoing interventional procedures , the complication rate remains within acceptable limits .
in a study comparing capsule endoscopy ( ce ) with dbe for gastrointestinal bleeding of unknown cause , it was found that both methods could identify the source of bleeding in some cases(table 1 ) . in a meta - analysis study that compared ce with dbe ,
the diagnosis rates for vascular , inflammatory , and polypoid lesions were similar ( figs . 2 - 4 ) .
the general diagnosis rate of these methods was also similar ( ce , 60% ; dbe , 57% ) .
in dbe , although the diagnosis rate of obstruction and bleeding of unknown origin are 81.3% and 80.6% , respectively , the diagnosis rates of diarrhea and abdominal pain are 36.5% and 37.7% , respectively .
dbe has been found to be cost - effective for the diagnosis of bleeding of unknown origin . even though dbe is invasive and
its duration of training and procedure time is long , it is usually the first choice as a therapeutic intervention in suitable patients .
thus , under appropriate conditions , both procedures are good and complementary to each other . depending on the clinical experience and the available equipment , a different and specific approach for each patient
if guidance can be obtained via radiologic methods , either dbe or direct surgery may serve as the first choice .
enteroscopy via the oral route may also be preferred for patients with active bleeding when no radiologic guidance is available .
dbe should not be performed in patients who have latex allergy . instead , single - balloon enteroscopy may be preferable in such cases . in disorders of the small intestine other than bleeding of unknown cause
in addition , dbe permits anal entry during the same session . moreover , dbe can be used to exclude diagnoses in suspicious cases , obtain biopsy specimens from suspicious areas , and achieve dilatation of the stenosis in crohn disease . in a study that compared dbe with single - balloon enteroscopy , dbe was shown to be three times more effective than total enteroscopic examination .
however , single - balloon enteroscopy was reported to be quicker and easier to learn .
the use of an additional cannula system and co2 instead of indoor air has also shown to increase the technical achievement rate with dbe , and decompress air during the examination in order to make deep intubation .
moreover , the placement of metal stents for malignant stricture of the small intestine is possible .
clinical admissions and alarming symptoms in patients are the main factors through which a treatment method is selected .
even if the result of ce is negative , enteroscopy or intraoperative enteroscopy should be performed if there is clinical suspicion .
 advances in technology have facilitated the common use of small - bowel imaging . 
 intraoperative enteroscopy was the gold standard method for small - bowel imaging 
 . however , noninvasive capsule endoscopy and invasive balloon enteroscopy are currently the main endoscopic procedures that are routinely used for small - bowel pathologies , and the indications for both techniques are similar . 
 although obstruction is a contraindication for capsule endoscopy , it is not considered to be problematic for double - balloon enteroscopy . 
 the most important advantage of double - balloon enteroscopy is the applicability of therapeutic interventions during the procedure ; however , double - balloon enteroscopy has certain advantages as well as disadvantages . 
INTRODUCTION
INDICATIONS AND CLINICAL SUCCESS
COMPARISON OF DBE WITH OTHER SMALL-BOWEL IMAGING METHODS
NEW DEVELOPMENTS
CONCLUSIONS