Have we really understood when the efforts of laparoscopic liver resection are justified?-a complexity-based appraisal of the differential benefit.

Background: The implementation of minimally invasive liver resection surgery (MILS) programs starts from procedures with a low degree of technical difficulty. Data regarding the real short-term advantage of laparoscopy according to technical difficulty are still lacking. The aim of the present study is to evaluate the differential benefit of laparoscopic over open technique according to the technical difficulty of the procedures and to investigate if efforts associated with laparoscopic approach are always justified. Methods: Nine hundred and thirty-six MILS resections performed between 2005 and 2018 were stratified according to technical complexity (low, intermediate and high difficulty) and to approach (MILS or open) and matched in a 1:1 ratio using propensity scores to obtain three pairs of groups (Pair 1: Low-MILS and Low-Open, including 274 cases respectively; Pair 2: Int-MILS and Int-Open, including 237 patients respectively; Pair 3: High-MILS and High-Open, including 226 patients respectively). Results: MILS approach resulted in a statistically significant lower blood loss, reduced morbidity, reduced and shorter time for functional recover and length of stay within all pairs. The evaluation of the differential benefit showed a greater advantage of laparoscopic approach in high degree procedures compared with intermediate and low degree, both in terms of blood loss (-250 and -200 mL respectively) and morbidity rate (-5.7% and -4.1% respectively). Conclusions: The favorable biological scenario associated with laparoscopic approach allows to obtain significant benefits in the setting of technically complex procedures. The commitment towards MILS approach should be therefore stronger in this setting, where the advantage of laparoscopy seems to be enhanced.