Recovery of the Psoas Muscle Index in Living Donors after a Right Lobe Hepatectomy for Liver Transplantation: A Single-Center Experience

Objective: The development of sarcopenia leads to adverse postoperative outcomes. However, no study has investigated perioperative loss in core muscle and the correlation between core muscle and residual liver volume in living donors for liver transplant. Patients and Methods: A total of 457 adult healthy donors who underwent a right lobe hepatectomy without the middle hepatic vein for elective liver transplant were retrospectively analyzed. Abdominal computed tomography was performed within 1 month before surgery and the first week and 3 months after the surgery. The average psoas muscle area between lumbar vertebrae 3 and 4 was measured and normalized by height squared (psoas muscle index [PMI] = psoas muscle area/height²). The initial whole liver volume and remnant left lobe volume were measured on computed tomography images. Results: The study cohort included 279 men (61.1%) and 178 women (38.9%). The median preoperative PMIs were 420.9 mm²/m² (interquartile range, 360.6–487.0 mm²/m²) in men and 280.9 mm²/m² (interquartile range, 243.5–318.7 mm²/m²) in women. The PMIs in men and women significantly decreased during the first week after surgery, and gradually recovered to preoperative levels during the first 3 months after surgery. Based on the ratio between the remnant left lobe and initial whole liver volume (≥30%), the increase in remnant left lobe volume was not correlated with the decrease in PMI on postoperative day 7. A postoperative U-shaped recovery in the core muscles was present in both male and female donors, independent of the remnant liver ratio. Conclusions: Despite the requirements of partial liver regeneration and surgical wound repair, healthy donors did not suffer from sustained core muscle loss after surgery.