Accuracy and inter-operator variability of small bowel length measurement at laparoscopy

Benny Gazer, MD¹, Avinoam Nevler, MD¹, Barak Bar-Zakai, MD², Udi Willentz, DVM³, Ofer Doron³, Mordechai Gutman, MD¹, Danny Rosin, MD¹. ¹Chaim Sheba Medical Center, ²Kaplan Medical Center, ³Lahav CRO

Introduction: Measurement and assessment of bowel length is a necessary surgical skill needed in various laparoscopic procedures to achieve good outcomes and avoid complications such as postoperative malabsorption or blind loop syndrome. The current study is aimed at assessing reliability and interrater variability of small bowel length assessment during laparoscopic procedures in an in-vivo porcine model, as the first step towards developing a standardized laparoscopic method for measuring small bowel length.

Methods: Ten senior surgeons, experienced in laparoscopic surgery (>1000 Laparoscopic Procedures) were required to assess and mark randomly assigned lengths of small bowel (range 25-197cm) in both laparoscopic and open approaches using color coded vessel loops (Figure 1) in an in- vivo porcine model. The marked distances were later measured by the researchers with surgical tape measure, and actual distances were compared to the pre-assigned distances. Means of measurements and differences were calculated for the laparoscopic and open phases. Bland-Altman plots and one sample t-tests were performed using the Statistics Package for Social Studies (IBM SPSS Statistics Ver.20). This study was approved by the regional animal bioethics committee.

Results: In the laparoscopic phase of the experiment, all the measurements were shorter than the assigned distances (Interquartile range 58.9-79.0%). The difference between the assigned distances and the distances assessed by the participants was 33.8 cm±28.7cm. This difference was statistically significant (P<0.001, 95%CI 17.8-49.7, Figure 2).

In the laparotomy phase, the mean difference and standard deviation were lower (1.5cm±SD 15cm) and not statistically significant (P =0.7) as shown in Figure 3.

Conclusions: The results of our study suggest that small bowel length assessment during laparoscopic procedures is inaccurate and non-reliable with a substantial inter-operator variability. Laparoscopic assessments were repeatedly shorter than requested. These results stress the need for developing a standard laparoscopic technique for measuring small bowel length which is simple, reproducible, and easy to learn.

Figure 1