Critical Appraisal and Clinical Significance of the Variations in the Portal and Hepatic Venous Anatomy in Liver Surgery

Introduction: Anatomical variations of the portal(PV) and hepatic veins(HV) are of significance in the planning and execution of liver resections and LDLT surgery. The current study is aimed at critical assessment of correlation among the anomalies of PV and HV that may be of further clinical significance. Methods: One hundred consecutive patients who had a dual phase CT contrast study prior to liver surgery were included. Anatomical variants were retrospectively recorded according to Nakamura classification for PV and Soyer classification for HV. Scans with distorted anatomy due to large lesions, previous surgery, inadequate images were excluded. Results: Sixty five patients were included. Conventional anatomy was most commonly encountered in the PV(Type A: 73%) compared to HVs. Single trunk of the HV(normal) that helps in planning appropriate venous reconstruction is seen with MHV:63%, LHV:38%, RHV:26%. Single trunk of all the 3HVs is noted in 6%. Early branching (Type B)(35%) and leash of vessels in the right posterior segment(Type C)(31%) are the common variants of RHV and needs considered while performing anatomical/non-anatomical resections of segments 5,6,7. Common LHV and MHV trunk with early division of LHV is the common variant of LHV (38%) and will need attention in laparoscopic left/left lateral hepatectomy. PV variant anatomy is rarely associated with conventional anatomy of all 3HVs(2%). Conclusion: Awareness of the association of variations of HV, PV might help younger surgeons in mitigating intra-operative risks of bleeding and venous ischemia. Further appraisal of the results will help consolidating the above clinically useful information.