Background: Postoperative liver regeneration is essential for maintaining hepatic function. This study evaluated the rate, determinants, and volumetric patterns of early liver regeneration after hemihepatectomy. Methods: A retrospective review was conducted of 50 patients who underwent right or left hemihepatectomy between April 2019 and March 2025. Liver and spleen volumes (SV) were assessed preoperatively, at postoperative day (POD) 1 week, and at POD 3 months. Early liver regeneration rate (LRR) was defined as the percentage increase in remnant liver volume at POD 1 week relative to the preoperative future liver remnant (FLR), and patients were categorized into low (<50%) and high (≥50%) LRR groups. Clinical, biochemical, and volumetric variables were compared, and predictors of regeneration were identified using multivariable analyses. Regeneration patterns were also examined according to whether the FLR/standard liver volume (SLV) ratio was <50% or ≥50%. Results: FLR/SLV was the strongest independent predictor of rapid early liver regeneration (p<0.001). Remnants with FLR/SLV <50% exhibited rapid and sustained regeneration, whereas those with FLR/SLV ≥50% showed slower regrowth that plateaued after reaching approximately 90% of SLV. SV increased at POD 1 week in all patients; however, only the FLR/SLV ≥50% group showed a reduction by POD 3 months, whereas the <50% group maintained elevated volumes. Conclusions FLR/SLV reliably predicts early postoperative liver regeneration. Smaller remnants regenerate more rapidly, whereas persistent splenic enlargement suggests a sustained portal hemodynamic burden. Combined evaluation of FLR/SLV and SV may enhance perioperative risk assessment and surgical planning.

Background: Platelet-rich plasma (PRP) has been proposed to enhance liver regeneration, but its effects remain inconsistent across experimental models. This study evaluated whether autologous PRP promotes hepatic regeneration after major hepatectomy in rabbits and assessed the feasibility of this experimental approach. Methods: Twenty-one male New Zealand white rabbits underwent major hepatectomy and received saline (control) or PRP via portal vein or subcutaneous injection. Survival, pre- and postoperative laboratory results, regenerated liver weight, biochemical markers, and histologic features were compared. Results: Overall survival was 42%. Portal vein injection resulted in significantly higher mortality than subcutaneous injection (66% vs. 33%; p=0.050). Regenerated liver weight (approximately 60–70 g) and the graft-to-body weight ratio did not differ between groups. One PRP-treated rabbit demonstrated pronounced hepatic plate thickening, but overall regenerative markers showed no significant benefit. PRP preparations displayed variable leukocyte content. Conclusions PRP did not provide a measurable regenerative advantage in this rabbit major hepatectomy model. The high mortality and heterogeneous PRP composition emphasize the need for safer experimental designs and standardized PRP preparations to accurately assess its regenerative capacity.