Histologic features after surgery associating liver partition and portal vein ligation for staged hepatectomy versus those after hepatectomy with portal vein embolization

Objective. We compared histologic findings in nonneoplastic portions of liver resected during surgery associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) with those from hepatectomy after portal vein embolization (PVE). Summary background data. Effects of congestion and ischemia in ALPPS on hepatocyte regeneration are incompletely understood, as are those on hepatocyte maturity. Methods. Specimens obtained from 8 patients treated with ALPPS and from 14 patients treated with hepatectomy after PVE were examined by light and electron microscopy. Results. Extrapolated kinetic growth of the future liver remnant (FLR) for ALPPS was 14.4 +/- 4.8 mL/d, which was faster than for PVE (3.6 +/- 2.2 mL/d; P < .001). Microscopically, the FLR showed greater hepatocyte cell density and smaller hepatocyte size in ALPPS than in PVE (P < .01 for each). Bright appearing hepatocytes and sinusoidal narrowing were more frequent in ALPPS (50% and 50 %) than in PVE (0% and 8.3 %; P = .025 for each). In the deportalized ventral aspect of the anterior section, hepatocyte atrophy, hepatocyte degeneration or necrosis, sinusoidal dilation, fibrosis, and congestion were more frequent in ALPPS than in PVE (P = .001, P = .002, P < .001, and P < .001, respectively). Electron microscopy frequently showed vacant-appearing hepatocytic cytoplasm filled with glycogen granules in the FLR in ALPPS. Fewer cytoplasmic organelles and lipofuscin granules were observed in ALPPS than in PVE. Conclusion. In the FLR, regenerative hepatocytes in ALPPS were morphologically immature compared with PVE. ALPPS should be performed with caution, considering limited functional increase in the FLR reflecting immaturity of the regenerative hepatocytes.