Topological approach of liver segmentation based on 3D visualization technology in surgical planning for split liver transplantation

Abstract

BACKGROUND Split liver transplantation (SLT) is a complex procedure. The left-lateral and right tri-segment splits are the most common surgical approaches and are based on the Couinaud liver segmentation theory. Notably, the liver surface following right tri-segment splits may exhibit different degrees of ischemic changes related to the destruction of the local portal vein blood flow topology. There is currently no consensus on preoperative evaluation and predictive strategy for hepatic segmental necrosis after SLT. AIM To investigate the application of the topological approach in liver segmentation based on 3D visualization technology in the surgical planning of SLT. METHODS Clinical data of 10 recipients and 5 donors who underwent SLT at Shenzhen Third People’s Hospital from January 2020 to January 2021 were retrospectively analyzed. Before surgery, all the donors were subjected to 3D modeling and evaluation. Based on the 3D-reconstructed models, the liver splitting procedure was simulated using the liver segmentation system described by Couinaud and a blood flow topology liver segmentation (BFTLS) method. In addition, the volume of the liver was also quantified. Statistical indexes mainly included the hepatic vasculature and expected volume of split grafts evaluated by 3D models, the actual liver volume, and the ischemia state of the hepatic segments during the actual surgery. RESULTS Among the 5 cases of split liver surgery, the liver was split into a left-lateral segment and right tri-segment in 4 cases, while 1 case was split using the left and right half liver splitting. All operations were successfully implemented according to the preoperative plan. According to Couinaud liver segmentation system and BFTLS methods, the volume of the left lateral segment was 359.00 ± 101.57 mL and 367.75 ± 99.73 mL, respectively, while that measured during the actual surgery was 397.50 ± 37.97 mL. The volume of segment IV (the portion of ischemic liver lobes) allocated to the right tri-segment was 136.31 ± 86.10 mL, as determined using the topological approach to liver segmentation. However, during the actual surgical intervention, ischemia of the right tri-segment section was observed in 4 cases, including 1 case of necrosis and bile leakage, with an ischemic liver volume of 238.7 mL. CONCLUSION 3D visualization technology can guide the preoperative planning of SLT and improve accuracy during the intervention. The simulated operation based on 3D visualization of blood flow topology may be useful to predict the degree of ischemia in the liver segment and provide a reference for determining whether the ischemic liver tissue should be removed during the surgery.

How to apply ex-vivo split liver transplantation safely and feasibly: A three-step approach

“…Additionally, adherence to conventional criteria for SLT, such as the graft-to-recipient weight ratio (GRWR), is crucial. Typically, a GRWR greater than 1% for adults[ 8 , 15 ] and between 2% to 4% for children is recommended. In our study, all the 25 recipients of SLT met these criteria and did not experience postoperative complications such as large-for-size or small-for-size graft syndromes.…”

“…Reyes et al [ 17 ] previously reported that the survival rates of recipients undergoing in-situ and ex-vivo liver splitting were comparable and similar to the survival rates of WLT recipients, in line with the findings of our study. Our literature review revealed that the majority of transplant centers have a preference for the in-situ liver-splitting approach[ 8 , 12 , 18 ]. In-situ liver splitting involves performing the procedure within the donor’s body for liver procurement.…”

“…Given the current organ shortage crisis, split liver transplantation (SLT) has emerged as a promising alternative for select patients with end-stage liver disease[ 1 - 4 ], offering clinical outcomes akin to those achieved through whole liver transplantation (WLT)[ 5 - 7 ]. The techniques for SLT involve primarily splitting off the left lateral section and the right trisegment, followed by further partitioning into the left and right hemi-livers or liver segments, contingent on the compatibility conditions between the donor and recipient[ 8 , 9 ].…”