The unwanted third wheel in the Calot's triangle: Incidence and surgical significance of caterpillar hump of right hepatic artery with a systematic review of the literature

BACKGROUND: Caterpillar hump of the right hepatic artery is a rare variation increasing the risk of vascular and biliary injuries during hepatobiliary surgery. The aim of this study is to record the cases of the right hepatic artery forming caterpillar hump in a cohort of patients underwent laparoscopic cholecystectomy and to report a review of the literature systematically conducted. METHODS: We reviewed clinical and surgical video data of 230 patients with symptomatic cholelithiasis treated with laparoscopic cholecystectomy between January 2016 and August 2017. A systematic literature search in PubMed, Medline, Cochrane and Ovid databases until 30th June 2017 was also performed in accordance with the PRISMA statement. RESULTS: Our institutional data indicated that 1.3% of 230 patients presented caterpillar hump right hepatic artery. The systematic review included 16 studies reporting data from a total of 498 human cadavers and 579 patients submitted to cholecystectomy. The overall proportion of surgical patients with the caterpillar hump right hepatic artery was 6.9%. CONCLUSIONS: Variations of the cystic artery are not just an anatomical dissertation, assuming a very crucial role in surgical strategies to avoid uncontrolled vascular lesions. A meticulous knowledge of the hepatobiliary triangle in association with all elements of 'Culture of Safety in Cholecystectomy' is mandatory for surgeons facing more than two structures within Calot's triangle.