Objective:To study the impact of donor left hepatic vein classification and the reconstruction methods on hepatic venous outflow obstruction (HVOO) after pediatric living-donor liver transplantation using left lateral liver segments.Methods:A retrospective study was performed on the clinical data of 653 children recipients who underwent living-donor liver transplantation with left lateral liver segments from January 2014 to December 2020 at Tianjin First Central Hospital. There were 309 males and 344 females, aged 7.0 (6.0, 10.0) months, with an age range of 3-121 months. Based on the left hepatic vein on preoperative donor enhancement CT as well as the intraoperative reconstruction methods, the recipients were divided into 3 groups: type Ⅰ group ( n=514), anastomosis using a single opening was performed directly between the donor and the recipient; type Ⅱ group ( n=118), angioplasty was performed on two adjacent recipient venous orifices before anastomosis, and type Ⅲ group ( n=21), an interposition vessel was anastomosed to two widely spaced openings or the two veins were anastomosed separately. The preoperative general status of the patient, postoperative HVOO incidences, and graft and recipient survival rates were compared among the three groups. The patients were followed up by outpatient reexamination or telephone. Results:Graft to recipient weight ratio in the type Ⅲ group was smaller than that in the type Ⅰ group and the type Ⅱ group ( P<0.05). For all the 653 patients, the incidence of postoperative HVOO was 4.59% (30/653), with the incidences of HVOO in the 3 groups of patients were 4.1% for the type Ⅰ group (21/514), 5.1% for the type Ⅱ group (6/118), and 14.3% for the type Ⅲ group (3/21), respectively. There was no significant difference among the groups ( P>0.05). The recipient cumulative survival rates at 1 and 3 years after surgery in the type I group were 97.8% and 97.0%, and the corresponding rates in the type Ⅱ group were 96.5% and 94.2%, and in the type Ⅲ group were 94.1% and 86.9%, respectively. There was a significant difference between the type Ⅰ and type Ⅲ groups ( P=0.048). The graft cumulative survival rates at 1 and 3 years in the type Ⅰ group were 97.4% and 96.9%, and the corresponding rates in the type Ⅱ group were 94.9% and 92.5%, and in the type Ⅲ group were 94.1% and 86.9%, respectively. The difference in the postoperative graft cumulative survival rates between the type Ⅰ group and type Ⅱ group was significant ( P=0.044). Conclusions:The anatomy of the left hepatic vein supplying the left lateral liver segment was highly variable, and the majority of the variations could be reconstructed. A reasonable reconstructive method could reduce the incidence of postoperative HVOO and improved the outcomes of the graft.