A randomized comparative study evaluating water-jet with CUSA for parenchymal dissection in living-donor liver procurement: WORLD trial.

Introduction: Water-Jet (WJ) dissection is an innovative technique for liver surgery that uses high-pressure saline jets to selectively dissect liver parenchyma while preserving vascular and biliary structures. Compared to the Cavitron Ultrasonic Surgical Aspirator (CUSA), WJ offers advantages such as reduced thermal damage, lower blood loss, and shorter operative times. These benefits are particularly important in living-donor liver transplantation (LDLT), where donor safety and rapid recovery are critical. This WORLD trial ("W"ater-Jet versus CUSA f"o"r Liver Pa"r"enchymal Transection in "L"iving "D"onor Liver Transplantation) aims to compare the efficacy and safety of WJ and CUSA in LDLT.

Methods and analysis: This single-blind, randomized controlled trial will include 48 living liver donors, allocated in a 1:1 ratio to the WJ or CUSA group. Experienced surgeons will perform liver parenchymal transection using standardized protocols. The primary endpoint is transection speed (cm²/min), with secondary outcomes including operative time, blood loss, complication rates, length of postoperative hospital stays, and postoperative liver function tests. Statistical analysis will assess the non-inferiority of WJ using JMP and R software, with a one-sided α of 2.5% and 80% power.

Ethics and dissemination: This study protocol was approved by the institutional review board of Kyushu University (No. 20232001). The study is registered in UMIN-CTR as UMIN000051662. Written informed consent will be obtained from all participants. The results will be published in a peer-reviewed journal and will be presented at medical meetings.