Clinical relevance of the caudate linguiform process (ponticulus hepatis) in human liver

Background: The caudate linguiform process (CLP), also known as Ponticulus Hepatis, is loosely defined as a bridge of hepatic parenchyma that overlaps the inferior vena cava (IVC) fossa, occasionally converting it into a canal. The primary objective of this study was to document anatomic variants of the CLP in the human liver. A secondary objective was to perform a systematic literature review of the CLP. Methodology: We analyzed cadaveric livers and selected those with a CLP for detailed examination. Two types of CLPs were defined: A partial CLP that leaves >9 mm of retrohepatic IVC exposed and a complete CLP that leaves <10 mm of IVC surface visible. The following data were recorded: CLP height, CLP width, CLP thickness, relationship to IVC, and width of exposed IVC. Results: A CLP was present in 36 (64%) of 56 cadaveric livers studied. There were 15 (41.7%) complete CLPs and 21 (58.3%) incomplete CLPs. Complete CLPs had a mean height of 54.22 ± 11.20 mm, width of 12.51 ± 3.56 mm, thickness of 7.39 ± 3.93 mm, and left only 6.38 ± 1.75 mm of exposed IVC. The incomplete CLPs had a mean height of 51.36 ± 11.19 mm, width of 11.44 ± 3.25 mm, thickness of 9.49 ± 4.38 mm and left 13.43 ± 3.35 mm of IVC exposed and accessible. Conclusions: We have proposed exact definitions of the CLP using specific anatomic points that are radiologically identifiable, reproducible, and clinically relevant. There is a high prevalence of CLPs in this population, with 42% being complete CLPs. By preventing access to the retrohepatic IVC, a CLP increases the technical complexity of the surgery.