A simple and accurate formula to estimate left hepatic graft volume in living-donor adult liver transplantation

Background. In the field of living-donor adult liver transplantation, a small-for-size graft often occurs, particularly when using left-lobe grafts. This is because of the limited volumes associated with left-lobe grafts. The accurate preoperative evaluation of graft volumes is crucial to avoid this complication. The aim of this study is to clarify the usefulness of a new formula to estimate the left-lobe graft volume. Method. In 61 left-lobe grafts, a new formula was created with stepwise regression analysis using the following variables: height, weight, the thoracic and abdominal distance from anterior to posterior side (A-P), and distance from left to right side (L-R) of the initial 20 donors. With another 41 donors, the difference between the actual and estimated graft volume using the formula and two-and three-dimensional computed tomography was prospectively evaluated. Results. On the basis of the results of the stepwise regression analysis, a new formula was created as follows: graft volume (ml)=313.4+7.7xweight (kg)-12.6xthoracic L-R (cm). The difference between the actual and estimated graft volumes using the formula was significantly better (10.8±9.5%) than that of the volumetry using two-dimensional computed tomography (16.3±10.1%) (P<0.05). Conclusions. In conclusion, the new formula can estimate the actual graft volume more accurately than conventional volumetry with two-dimensional computed tomography. The formula is useful to estimate the volume of left-lobe graft in living-donor adult liver transplantation.