The segment IV approach: a useful method for achieving the critical view of safety during laparoscopic cholecystectomy in patients with anomalous bile duct

Background The critical view of safety (CVS) method can be achieved by avoiding vasculo-biliary injury resulting from misidentification during laparoscopic cholecystectomy (LC). Although achieving the CVS has become popular worldwide, there is no established standardized technique to achieve the CVS in patients with an anomalous bile duct (ABD). We recently reported our original approach for securing the CVS using a new landmark, the diagonal line of the segment IV of the liver (D-line). The D-line is an imaginary line that lies on the right border of the hilar plate. The cystic structure can be securely isolated along the D-line without any misidentification, regardless of the existence of an ABD. We named this approach the segment IV approach in LC. Methods In this study, we adopted the segment IV approach in patients with an ABD. Results From October 2015 to June 2020, 209 patients underwent LC using the segment IV approach. Among them, three (1.4%) were preoperatively diagnosed with an ABD. The branching point of the cystic duct was the posterior sectional duct, anterior sectional duct, or left hepatic duct in each patient. The CVS was achieved in all cases without any complications. Conclusion It is a promising technique, especially even for patients with an ABD during LC.