Background and study aims: In double-balloon enteroscopy (DBE) the use of a reliable and practical method to
calculate the insertion depth of the endoscope could help to improve diagnosis accuracy
and optimize the effort and cost of the technique. The objectives of this work were
to compare and evaluate two methods of estimating the insertion depth and to obtain
a descriptive model capable of representing the exploration dynamics and efficiency
in terms of advanced distance and time.
Methods: Oral DBE was performed in 25 pigs. Insertion depth was calculated during the procedure
by: 1) estimation of time and distance for each push and pull cycle during progression;
and 2) estimation of distance during withdrawal. At the maximum insertion depth a
tattoo was placed, and the observed measures for the two methods were compared with
the distance between the pylorus and the mark after euthanasia and necropsy of the
animals 1 week after DBE.
Results: The average insertion depth during progression, withdrawal, and after necropsy was
324.92 cm, 317.23 cm, and 342.05 cm, respectively (P
Anova = 0.72). The Pearson correlation coefficient (r > 0.85; P < 0.001) and paired Brand – Altman plots demonstrated high agreement between progression
and necropsy (0.03 % difference) and between withdrawal and necropsy (6.9 % difference).
The exploration dynamics and efficiency in terms of advanced distance per cycle and
time fitted to potential and logarithmic regression models, respectively.
Conclusions: Measurement of insertion depth in vivo was validated in the porcine model during
progression and withdrawal. Estimation during progression was more accurate and allowed
exploration dynamics and efficiency to be plotted, which might be used as approximate
reference values for humans.
