Page 22 - Read Online

Page 2 of 11 Ziogas et al. Mini-invasive Surg 2020;4:69 I http://dx.doi.org/10.20517/2574-1225.2020.63

INTRODUCTION
The introduction of minimally-invasive technology in the approach of liver disorders in the early 1990s
[1-5]
has since revolutionized the field of liver surgery . Laparoscopic liver surgery does not only include pure
laparoscopy, but also hand-assisted laparoscopic, as well as hybrid approaches, where the initial part of the
procedure (i.e., liver mobilization, early dissection) is done laparoscopically, while later a small incision is
made to complete the transection of the liver parenchyma . The liver is classified in individual territories
[6,7]
[8,9]
according to the segmentation of the vessels and bile ducts, introduced by Couinaud in the 1950s , and
the Brisbane 2000 nomenclature is utilized to define minor and major hepatectomy in the field of liver
surgery [10,11] . Minor hepatectomy is defined as the resection of two or fewer Couinaud segments, while major
hepatectomy is the removal of three or more Couinaud segments . The first series on laparoscopic liver
[11]
resections consisted mostly of minor liver resections [3,4,12,13] . The first laparoscopic major hepatectomy (LMH)
was performed in 1997 . The higher risk for uncontrolled hemorrhage and the requirement of advanced
[14]
technical expertise, particularly related to major vessel dissection, have slowed the broader adoption of
minimally-invasive approaches for major hepatectomy .
[15]
The technological advances of our era have also led to the broader implementation of robotics in several fields
of surgery, including liver surgery. The ability to obtain three-dimensional and magnified intraoperative
vision, the significant decrease in hand tremor, as well as the benefit for the surgeon of operating under more
relaxed and comfortable circumstances, have led to a considerable growth in robotic surgery, which can
overcome the rigid instrumentation and the limited two-dimensional vision associated with laparoscopic
surgery [16,17] . These characteristics, along with the advent of wristed instruments, can lead to improved
dexterity and higher precision in surgical dissection; this is of particular benefit to liver resection, as hilar
dissection, curved transection of the liver parenchyma and the resection of lesions in the posterosuperior
segments can be more feasible with the use of a robot . The first large series of robotic liver resection was
[18]
reported in 2002 , and although most current experience is based on minor resections, several studies
[19]
have reported robotic major hepatectomy (RMH). This review aims to summarize the current state of
evidence about the outcomes after LMH vs. RMH. We acknowledge that there is still a very important
role for open hepatectomy in cases of multiple bilobar liver tumors or large tumors near critical vascular
structures. However, we will focus on the differences between LMH and RMH, as a full review of open
major hepatectomy is beyond the scope of this review.

INTERNATIONAL CONSENSUS AND LEARNING CURVES
Before engaging in a head-to-head comparison between LMH and RMH, it is worth mentioning two points
that may favor the former approach. First, LMH has been performed for many more years than its robotic
counterpart; second, irrespective of the procedural, hospitalization, and total economic cost, the cost of
purchasing a robot for a hospital is considerable and has been a major limiting factor to the broader adoption
of robotic liver surgery. These two points are of paramount importance, as data suggest that outcomes
improve as experience with a surgical approach grows . It is also worth mentioning that during the second
[20]
international consensus on laparoscopic liver surgery (Morioka 2014), the jury concluded that laparoscopic
minor hepatectomy had at that point already become standard practice, while LMH was still considered
to be an innovative procedure still under exploration . According to the 2018 international consensus
[11]
statement on robotic hepatectomy, RMH was deemed to be as safe and feasible as both LMH and open major
hepatectomy .
[21]

For the purpose of this review, we performed a non-systematic search of the PubMed bibliographic database
using combinations of the following terms: “laparoscopic”, “robotic”, “minimally invasive”, “hepatectomy”,
“major hepatectomy”, “liver resection”, and “major liver resection” (last search March 2020). We included
comparative or non-comparative studies reporting on the number of LMH and RMH cases. Tables 1, 2, and 3
present the previously published cases of RMH and LMH [6,7,12-14,20,22-109] , and it is apparent that the experience
with LMH is greater than that of the robotic approach.