Double- vs. single-balloon enteroscopy: and the winner is…
27 August 2012 (online)
We read with interest the review by May on balloon-assisted enteroscopy . The author concluded that double-balloon enteroscopy (DBE) is superior to single-balloon enteroscopy (SBE). However, we would like to make some comments.
SBE represents one emerging technique for deep enteroscopy, in parallel with DBE and spiral enteroscopy. May focused her attention on the study by Takano et al. , in which a significant difference was found between DBE and SBE with respect to total enteroscopy rate (57 % and 0 %, respectively; P = 0.002). However, this study has two significant limitations. First, the authors had much more experience with DBE than with SBE: when they started the study, they had performed 248 DBE procedures but only 10 SBE procedures. Second, only 14 SBE procedures were carried out during the 24-month study period. This low case volume would have delayed the learning curve and made it difficult to achieve an adequate skill level. An indirect test that confirms this is the longer examination time and radiographic fluoroscopy time recorded for SBE procedures (185.9 ± 34.9 minutes vs. 160.7 ± 29.0 minutes for examination time [P = 0.03] and 14.5 ± 7.0 minutes vs. 9.3 ± 5.0 minutes for fluoroscopy time [P = 0.03]). In a multicenter US study, Mehdizadeh et al. showed a significant learning curve in acquiring the skills necessary to perform balloon-assisted enteroscopy, with a significant decline in overall procedure time and fluoroscopy time after the first 10 DBE cases . Moreover, in contrast to the total enteroscopy rate, Takano et al. showed that the diagnostic yield and therapeutic yield were not significantly different between SBE and DBE procedures, and concluded that both techniques seem to be interchangeable in daily clinical gastroenterology practice.
Recently, Domagk et al. published the first randomized multicenter, head-to-head comparison trial of DBE (by Fujinon) vs. SBE (by Olympus). The study demonstrated the noninferiority of SBE with respect to the insertion depth and complete visualization in a considerable number of patients (130 procedures) over a short study period (12 months) . Previous experience with SBE demonstrated that the total enteroscopy rate with SBE was between 5 % and 25 %    . These findings might be explained in part by inexperience in using the SBE technique. In an Italian multicenter prospective study, presented during the 2011 United European Gastroenterology Week (22 – 26 October; Stockholm, Sweden), the authors found a total enteroscopy rate for SBE of 47 %, higher than that previously reported in the literature . The endoscopists participating in this study were experienced in the SBE technique and had performed at least 30 SBE procedures before starting the study. These results are comparable with those reported in a recent review on DBE published by Xin et al. . They reported data on total enteroscopy from 23 studies involving 1143 patients. Successful total enteroscopy was achieved in 569 patients and the consequent pooled total enteroscopy rate was 44.0 %; the rate was similar between the two procedures.
Incidentally, the question remains whether the technically appreciated end point of “total enteroscopy rate” is preferable over the end point of “clinical impact.” Although depth of insertion remains the most common question posed to endoscopists performing deep enteroscopy, the answer to this question is often irrelevant: it is neither the depth of insertion nor the total enteroscopy rate (which appear to be similar between the two procedures), that are important but rather the clinical impact of the enteroscopy. In other words, what is important is the ability of the procedure to detect lesions and to allow for a therapeutic intervention.
In conclusion, data published to date are conflicting. More comparative studies between DBE and SBE are necessary in order to nominate the winner.
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