Reply to Lenz et al.

We have read the letter of Lenz et al. with interest and would like to make some comments.

We agree that in our comparison trial only the Fujinon device was used for both the single-balloon and the double-balloon technique. The aim of the study had been to compare techniques, not scopes.

Concerning the relatively short period of training for the SBE technique in our study, it can be stated that both techniques are push-and-pull techniques and handling is easy to learn. The results demonstrate, that the training period was long enough. In our trial the complete enteroscopy rate in the SBE group was twofold higher than that in the Domagk study (22 % vs. 11 %) – despite the fact that Domagk et al. claim a greater experience with the SBE technique than our participating centers.

A third point concerns the presentation of first results of the study by Domagk et al. before completion of the study. Lenz et al. state that preliminary results were not presented at the UEGW 2010 in Barcelona before completion of the study. But the first (preliminary) results, with 71 patients, were presented at UEGW 2009 in London, as published in GUT November 2009, vol 58, Suppl II (not 2010, this was a mistake on my part).

Within this abstract complete enteroscopy was defined as the only primary end point, whereas insertion depth and other parameters were defined as secondary end points. The rate of complete enteroscopy had been 15 % for the DBE group and 6 % for the SBE group at that time. Therefore, at least on the basis of the abstract, a change in the definition of the primary end point was made. In addition, it is unusual to define more than one primary end point for a study.

Complete enteroscopy rates can be estimated for general “routine” experience as approximately 20 % – 40 % [1] [2]. For experienced centers higher rates should be expected, at least if the study is focusing on that point. Furthermore, it was stated, that the diagnostic yield of both methods is similar and the two enteroscopy techniques are therefore equal. This is partly correct, because the diagnostic yield shows only one side of the coin. In the case of those diseases that often present with multifocal lesions (e. g. angiodysplasias, Crohn’s stenoses, polyps), a diagnosis can be made if one lesion is detected, but for therapeutic and clinical management, the extent of a disease is often important. For example, in the case of multiple angiodysplasias that are spread over the small bowel in a patient with anemia, it is desirable to treat as much of them as possible. Additionally, the term “diagnostic yield” does not encompass the value of a negative complete enteroscopy, which can be important for the further management of a patient.

Finally, it should be pointed out, that of course not all patients need a complete enteroscopy. In our experience this is necessary only in approximately 20 % – 25 % of all the patients with an indication for enteroscopy. Of course, good results can be achieved with all enteroscopy techniques, depending on the experience of the endoscopist. Complete enteroscopy is a suitable parameter for studies from the scientific point of view, because it is an objective parameter. On the other hand, it signifies deep insertion and demonstrates the value of the second balloon if it is really needed, e. g. in difficult anatomy or if a very deep insertion or complete enteroscopy is mandatory.

• References

• 1 Xin L, Liao Z, Jiang YP et al. Indications detectability, positive findings, total enteroscopy, and complications of diagnostic double-balloon endoscopy: a systematic review of data of the first decade of use. Gastrointest Endosc 2011; 74: 563-570
• 2 Möschler O, May A, Müller MK et al. Complications in and performance of double-balloon enteroscopy (DBE): results from a large prospective DBE database in Germany. Endoscopy 2011; 43: 484-489