Use of Vernier caliper to measure diameter and anastomotic index of end‐to‐end jejunojejunostomy in horses

We thank Professors Gandini and Giusto for their careful review of our paper and their relevant comments. ¹  Contrary to their proposal, however, none of the studies in question actually measured diameter, even if they stated that they did. ² The same applies to a recent manuscript in Veterinary Surgery regarding small colon anastomosis. ³ Ideally, measuring diameter would require converting the anastomosis to a circular form, which was not done in these studies. In our study, we used “lumen size” and measured this from the antimesenteric to mesenteric side in the anastomosis and control segments. ¹

In our study, the inside forks of the caliper spanned the anastomosis—Figure 1 in Seitz‐Cherner et al. ¹ —and were spread until clear resistance to further expansion was reached. This measured lumen size under maximum expansion relative to a contiguous control segment, which was expanded in a similar manner to generate an anastomotic index. ¹ Presumably this use of the caliper produces the 20% increase referred to by Gandini and Giusto, as in a clinical case with anastomotic distension. In this system, the same operator conducted measurements and the “stop” point of intestinal expansion by the caliper was recorded as a mean of three consecutive measurements per segment. To extend beyond that stop point could have disrupted the construct. However, we agree that there is a subjective element to this system and some form of standardization or calibration is needed.

FIGURE 1.

Anastomosis with mod‐IL pattern placed on ex vivo equine jejunum. Inner jaws of the caliper are inserted through stab incisions into the lumen to span the anastomosis before full expansion and final measurement. Note the expanded appearance of the anastomosis compared with the control segment (right).

Figure 1 from Seitz‐Cherner et al. does not show a segment markedly stretched ¹ and is therefore not comparable to the image from the paper by Baldwin and Gillen. ² The legend for our Figure 1 states that the caliper is in place “before full expansion and final measurement.” The legend also states that the segment appears “expanded compared to the control segment.” This appearance was generated purely by the anastomosis relative to the contiguous control segment, without expansion by the caliper. These images should therefore not be viewed collectively, contrary to what was proposed. Our Figure 1 supports an important concept because it demonstrates that the angled incision in the anastomosis can preserve lumen size, relative to a control segment. ¹

The concerns expressed by Gandini and Giusto regarding ex vivo versus in vivo measurements are confusing because a contrast is proposed for the comparison that they do not describe. We demonstrated a difference between in vivo and ex vivo conditions that should factor into the interpretation of ex vivo studies. We propose that muscular tone of the intestinal wall in vivo can counter expansion attempts. ¹ Consequently, data from ex vivo studies should be extrapolated to in vivo conditions with care. We are not quite sure why this conclusion is considered inappropriate within the study design, even if the measurement method may not be ideal.

We agree that the caliper method described by Gandini and Giusto ⁴ might be preferable to those used by Baldwin and Gillen² and St. Blanc et al. ³ Figure 1 from Seitz‐Cherner demonstrates correct usage, whereby the inside jaws of the instrument are used to spread the suture line and measure the internal length of the anastomosis simultaneously. ¹

We fully agree that the caliper method of measuring lumen expansion to assess anastomosis size is subjective and that we should seek better systems, as stated by Gandini and Giusto and addressed by Seitz‐Cherner. ¹ Although this topic is worthy of discussion and the method needs improvement, we might not fully agree with the negative impact that the limitations described have on the studies in question.

DATA AVAILABILITY STATEMENT

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.