Incidence of "Caterpillar hump" of right hepatic artery in the "Calot triangle" among a selected population in Sri Lanka. A chart review

Introduction: "Caterpillar hump" of the right hepatic artery in the triangle of Calot, is a rare variation that increases the risk of vascular and biliary injuries during laparoscopic cholecystectomy. This study aims to determine the prevalence of right hepatic artery forming "Caterpillar hump" in a selected cohort of patients who underwent laparoscopic cholecystectomy in a private hospital in Sri Lanka.Methods: A retrospective chart review was conducted to determine the prevalence of "Caterpillar hump" of the right hepatic artery among patients who underwent laparoscopic cholecystectomy for symptomatic cholelithiasis in a private hospital in Colombo, Sri Lanka, from 2015 to 2022. Data were retrieved from the available records at hospitals from 2015 to 2022. There were 79 patients recode during the study period. These records consist of manually written bed head charts, discharge summaries and electronic medical records. Patient records which did not clearly mention the Calot triangle vasculature or illegible handwriting were excluded from the study. Out of that, only 75 [94.9%] patients' charts were eligible for the study. Data on demographic and Calot triangle vasculature was recorded during surgery and retrieved from the hospital records. Ethical approval for the study was obtained from the hospital's ethical committee.Results: Among the patients who underwent laparoscopic cholecystectomy, 50 (66.7%) were female, and 25(33.3%) were male patients, with a mean (±SD) age of 57.4±4.8 years (range 18–81). The prevalence of the "Caterpillar hump" right hepatic artery in the calot's triangle among the study sample was 4 % ( 3/75). Two were females and one male. In all cases, the vascular variation was reported in a single-loop fashion, and no double-loop configuration was noted.Conclusions: This study showed that the right hepatic artery was subjected to this rare anatomical variation. This anomalous presentation increased the risk of vessel ligation or injury during laparoscopic Cholecystectomy. Thus, the awareness of caterpillar hump within Calot triangle, during surgical procedures is useful.