Robotic right living donor hepatectomy with intermittent inflow occlusion: true clinical benefit or just another chapter in the ischemic preconditioning story?

Right donor hepatectomy for living donor liver transplantation is predominantly performed through an open approach, with robotic hepatectomies remaining limited to highly specialized hepatobiliary centers. Against this background, Kunju and colleagues present what is, to our knowledge, the first randomized controlled trial addressing a specific technical modification—intermittent inflow occlusion (IIO)—in robotic right donor hepatectomy (1). The study is a timely and commendable effort in a field where prospective data remain scarce. The authors deserve therefore recognition for generating randomized evidence in this domain. The trial was conducted at a high-volume transplant center with experience beyond the robotic learning curve, and recruitment was completed within a remarkably short timeframe. These are meaningful strengths.

IIO was applied using Pringle maneuvers with 15-minute clamping intervals and 10-minute reperfusion phases, reaching a cumulative ischemic duration of approximately 42 minutes in the experimental arm. The result was a statistically significant reduction in intraoperative blood loss of approximately 55 mL. The question is less whether this difference is real than whether it translates into clinically meaningful benefit. In both study arms, absolute blood loss was already low, transfusion rates were not meaningfully affected, and donor safety was not in question. Blood loss is objective and measurable, but its suitability as a primary endpoint in modern minimally invasive donor hepatectomy (in a high-volume center) deserves consideration.

This finding becomes more nuanced when placed alongside other perioperative hemostatic strategies. Low central venous pressure (CVP) anesthesia has been shown in randomized settings to reduce blood loss in open surgery but not in minimally invasive liver surgery (2). The authors report the use of fluid-restricted anesthesia with low CVP, but detailed intraoperative hemodynamic data are unfortunately not provided. It therefore remains difficult to determine how consistently this strategy was applied across study arms. The effect attributed to IIO may partly reflect hemodynamic variability rather than a specific benefit of inflow occlusion itself.

The statistical assumptions of the trial design also warrant careful consideration. The sample size calculation was based on unpublished pilot data and assumed a mean blood loss difference of 125 mL—more than twice the 55 mL ultimately observed. Actual blood loss in both groups was also substantially higher than anticipated, and variability was considerable relative to the estimated effect size. When observed effect sizes diverge markedly from initial assumptions, the robustness of the power calculation may be affected. These discrepancies do not invalidate the findings but make it more challenging to interpret statistical significance as a direct indicator of clinical relevance.

Beyond the primary endpoint, the observation of lower postoperative transaminase levels and improved coagulation parameters in recipients of IIO grafts is an intriguing finding. The authors propose an ischemic preconditioning mechanism—brief hepatic ischemia attenuating subsequent ischemia–reperfusion injury in the transplanted graft. This explanation is biologically plausible but remains to be confirmed. No intraoperative biopsies were obtained, and no biochemical markers of ischemia–reperfusion injury were measured. The existing clinical evidence on ischemic conditioning in liver surgery is heterogeneous. In a randomized trial from our group evaluating ischemic preconditioning in liver resection, no significant differences in postoperative transaminase levels were observed, although the majority of patients underwent minor hepatectomies. In major hepatectomy, a true preconditioning may be observed as suggested by previous reports in the literature (3,4). Whether the findings of Kunju and colleagues reflect true preconditioning, however, cannot be fully determined from the available data.

The use of IIO has so far yielded conflicting results, suggesting that its effectiveness is likely context-dependent and influenced by surgical approach, extent of resection, and baseline hemorrhagic risk (5-7). In minimally invasive liver surgery, pneumoperitoneum, low CVP anesthesia, and refined parenchymal transection techniques already provide substantial hemostatic control, potentially limiting the incremental benefit of routine inflow occlusion (8-10). This perspective is supported by randomized data in robotic liver surgery, where comparable blood loss was observed without systematic inflow occlusion (11). From a technical standpoint, the parenchymal transection technique employed in this trial—bipolar energy in combination with monopolar shears—deserves further consideration. This approach is functionally comparable to the scissor hepatectomy technique, which has been shown to achieve precise dissection and reliable hemostasis in robotic liver surgery without the need for advanced energy devices (12). Its use in both study arms likely contributed to the low blood loss observed in both groups. Other outcomes were restricted to the early postoperative period, and 90-day morbidity as well as longer-term donor and recipient outcomes were not fully reported, leaving potential delayed effects uncertain. Generalizability may be influenced by center-specific practices, including the routine use of right lobe grafts with subtotal middle hepatic vein reconstruction, which may differ from approaches in other centers.

Taken together, this randomized trial represents an important contribution and a meaningful step toward evidence-based robotic liver surgery. IIO appears safe and feasible in this setting and may be associated with modest reductions in intraoperative blood loss. However, the clinical relevance of this reduction remains uncertain, and the observed differences in recipient biochemical parameters require further validation and mechanistic clarification. While safety and feasibility are clearly demonstrated, they alone may not be sufficient to justify routine adoption.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Translational Gastroenterology and Hepatology. The article has undergone external peer review.

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Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tgh.amegroups.com/article/view/10.21037/tgh-2026-0090/coif). The authors have no conflicts of interest to declare.

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