Reply to: “Minimize the Surgical Damage at the Stage-1 Operation by Combining Hybrid ALPPS and Nontotal Parenchymal Transection”
We would like to congratulate the authors for 2 successful Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) in a challenging situation reported by Lai et al.1 It confirms that the concept of the “hybrid ALPPS” is useful to achieve R0 resection of hepatic malignancy involving the right hepatic hilum. More importantly, it combined 2 components to minimize the surgical damage at the stage-1 operation to reduce postoperative complication: (i) hybrid ALPPS and (ii) nontotal parenchymal transection.
Hybrid ALPPS was proposed with the main objective of providing a “nontouch” technique with the oncological perspective of avoiding tumor spreading during the stage-1 operation, especially in patients with tumor infiltration of the right portal pedicel.2 Recently, the concept of combing in situ liver split with portal vein embolization (PVE) is systematically applied by de Santibañes et al,3 who are aiming to maximally reduce the aggressiveness and surgical impact of ALPPS at the first stage. In our practice, hybrid ALPPS is also a useful alternative in patients with portal trifurcation. In that case, the anterior branch of the right portal vein could be located far cranial to the posterior right portal vein, which makes a surgical division technical demanding.4
Partial ALPPS was advocated recently to minimizing the surgical complication after the first stage operation. Actually, the 2 cases we reported were indeed “hybrid partial ALPPS” per definition,2 as shown here by the 3-dimensional computer tomography reconstruction (Fig. 1). It was till 2015 that Petrowsky et al5 proposed to standardize the name of ALPPS with nontotal parenchymal transection at stage-1 operation as “partial ALPPS” to facilitate communication among clinicians. In the previous 2 cases in our report, partial ALPPS was achieved without dividing the dorsal portal vein branch of segment 4A to avoid transecting the segment 4 bile duct.2 This technical variation resulted from previous experience in which the bile leakage led to fatal outcome in patients with hilar cholangiocarcinoma after classic ALPPS.6 Since 2012, nontotal parenchymal transection was carried out systematically in the author's institute.4 In addition to minimization of the risk of bile leak, partial ALPPS could reduce the risk of hepatic ischemia by avoiding transection of the segment 4 artery or the middle hepatic vein.4
The Zurich group7 observed in an experimental model that partial (75%–80%) transection of the liver triggered a similar degree of hypertrophy of the future liver remnant compared with complete transection. On the basis of experimental observation and clinical implications, they switched from a complete to a well-defined partial transection (> 50% of the transection surface) in 2013.5 In partial ALPPS, a median hypertrophy of 60% was observed, compared with 61% after classic ALPPS approach, within a median time of 7 days. The results of the 2 cases from Lai et al and of our previous 2 cases found the same phenomenon with rapid hypertrophy of the future liver remnant could be achieved after “hybrid partial ALPPS.”
Among various technical variations to improve the patient safety,4 the concept of “partial ALPPS” not only lead to better outcomes in terms of liver-related complication,5,8 but also rise the question of liver hypertrophic triggers.7 Research on portal vein embolization, classic ALPPS and partial ALPPS might reveal the secret of rapid hypertrophy after liver partition.
We thank the authors to emphasize the “partial ALPPS” in the setting of hybrid procedure to ensure the patient safety. We share the same opinion of “minimal damage at the stage-1 operation” by “partial ALPPS” with the authors. Along with the development of laparoscopic liver surgery, hybrid partial ALPPS might be more extensively performed in a minimal invasive way to reduce the surgical complication.