Optimal instrument length for transumbilical laparoendoscopic single site (U-LESS) surgery

The aim of our study was to recommend a novel method for measuring the distance from the umbilicus to intra-abdominal organs, as well as recommend an instrument length that would accommodate transumbilical laparoendoscopic single-site (U-LESS) surgeries to these areas. From CT scans of 50 men and 50 women, we calculated the distance from the umbilicus to 11 intra-abdominal points of interest using two triangles oriented perpendicular to each other. Using known lengths of the triangles, we used the Pythagorean theorem to calculate distances with and without insufflation. Distances were measured from the umbilicus to the xyphoid process, superior most aspect of the spleen, neck of the gallbladder, bifurcation of the descending aorta, adrenal glands, superior pole(s) of the kidneys, inferior most aspect of the inguinal canal, suprapubic margin, and the apex of the prostate (or female bladder neck). We found that an instrument working length of 43 cm would be sufficient to facilitate U-LESS surgery for all of our patients to each of the measured points of interest. The technique described in this paper serves as a useful method by which to measure the distance from the umbilicus to any intra-abdominal point of interest. These measurements would allow surgeons to correctly select instruments with adequate length when planning to perform U-LESS surgery.