The Importance of Segment 4 Anatomy on Outcomes Following Living Donor Left Lateral Segmentectomy

During left lateral section (LLS) resection for live liver donation, the vascular inflow and the bile drainage of segment 4 (S4) are compromised. We investigated the long-term changes of S4 after donation and their potential prognostic impact on living liver donors.

This was a retrospective analysis of 42 consecutive left lateral (LLS, S2/3) liver resections for living donation.

There were 25 female and 17 male donors. Median age was 33 y and median body mass index was 26. Median LLS, S2/3, volume was 262 cc, and median sS4 volume was 160 cc. Complications were encountered in three donors (7%). An independent extrahepatic S4 artery (S4A) (with a proximal left heptic artery or a right hepatic artery origin) was identified in 41% of the donors. Ligation of the independent S4A was not associated with the rate of post resection liver dysfunction, complications, or the degree of S4 atrophy. Having a dominant S4 portal triad pedicle feeding the right anterior sectors, segment 5/8, of the liver was associated with increased parenchymal damage as evidenced by a higher peak of alanine aminotransferase but was not associated with postoperative complications. The median degree of atrophy of S4 at 1 y post donation as noted on imaging was 66%. The presence of a dominant S4 portal triad pedicle and the peak alanine aminotransferase early postoperatively were both predictors of the degree of S4 atrophy post donation.

The presence of an independent S4A or dominant S4 portal triad pedicle feeding the liver right anterior sectors, segment 5/8, should not be a contraindication for left lateral segment living donation.