**3.1 Major resections**

Major hepatectomies (resection of 3 or more contiguous segments) and extended hepatectomies with bile duct resections are complex, challenging procedures. High volume specialist centres have shown a minimally invasive approach to be feasible but the results from the only prospective randomised trial (ORANGE-II plus) are yet to be published [8, 10, 16]. At present, less than 10% of major liver resections are performed laparoscopically, largely due to the challenges posed by the location of the liver, its proximity to major vasculature and the difficulty in appreciating the complex biliary and hepatic vascular anatomy during a laparoscopic procedure [17]. Utilising a robotic approach may negate these disadvantages, with improved views and dexterity facilitating a precise hilar and hepatocaval dissection, advanced suturing and easier biliary-enteric anastomosis.

Specialised centres have published favourable outcomes (**Table 1**) and a limited number of multi centre comparative studies have demonstrated positive results [18–21]. A recent review of outcomes from 584 major robotic liver resections demonstrated acceptable blood loss, operation time, R0 resection rate, length of hospital stay and post op morbidity. When directly compared to laparoscopy, robotic major hepatectomies demonstrated significantly improved rates of post-operative


*RH, right hemi-hepatectomy; LH, left hemi-hepatectomy; RTS, right tri-sectionectomy; ERH, extended right hemihepatectomy; LLS, left lateral secitonectomy; SgVII, segment 6. Morbidity rate, includes post op complications from Clavien Dindo grades I-V. Mortality rate, 30 day post-operative mortality.*

### **Table 1.**

*Published series focused on outcomes following robotic major hepatectomies in the literature.*

critical care admission, 90 day re-admission rate and a similar length of stay and complication rate [22].

The robotic approach has also been shown to be feasible for simultaneous resection of a colorectal primary malignancy and the associated liver metastasis. Analysis of a small number of major hepatic resection with synchronous colorectal resection, demonstrated robotic resection to have acceptable morbidity and oncological outcomes [23].

The robotic approach has also been considered as an alternative to open surgery for hepatectomies requiring more extended resections and or biliary reconstructions. Outcomes published by 2 specialist centres demonstrated the robotic approach as a safe and feasible alternative to open surgery for hilar cholangiocarcinoma. However whilst technically feasible and safe, the results did not demonstrate equivalence to open surgery. Indeed they reported longer operative times and a higher estimated blood loss relative to open surgery. Furthermore, robotic resection was associated with poorer oncological outcomes with a lower recurrence free survival rate [24, 25].

Given the relative infancy of robotic innovation within the field of minimally invasive surgery, it is perhaps unsurprising that the literature around major robotic liver surgery is somewhat limited. The utility of a laparoscopic approach to major hepatectomy is only presently under investigation and any advantages relative to open surgery remains unestablished. Within this context, it is unclear if open or laparoscopic surgery should be the standard against which robotic surgery is held. At present, level II and III evidence suggests that robotic surgery is safe, feasible, and certainly non inferior to laparoscopic or open surgery. However it remains uncertain if this will translate to clinically significant short and long term outcomes in larger, prospective studies.

#### **3.2 Minor resections**

Minor hepatic resections, a category encompassing non-anatomical wedge resections, left lateral sectionectomies, segmentectomies and bisegmentectomies, are the most commonly performed minimally invasive hepatic operative interventions in both the laparoscopic and robotic settings [10, 17].

While the evidence discussed above suggests the multitude of technical advantages as well as non-inferiority of the robotic approach to major hepatic resections, it is pertinent to critically examine the role of robotic surgery in minor resections if aiming to confer improved operative outcomes to the greatest number of patients.

In keeping with the increasing trend for parenchymal sparing liver resection, non-anatomical and anatomical wedge resections are the mostly commonly performed robotic liver minor resection [10]. Indeed, a minimal access approach to resect only small amounts of hepatic tissue seems logical considering the morbidity associated with large abdominal incision; a position supported by international consensus in 2008 [26]. Particular difficulties exist, however, when performing laparoscopic in the postero-superior segments of the liver where a combination of the costal margin and rigidity of laparoscopic instruments conspire to make operative access difficult [12].

A number of robotic minor resection cases series from enthusiast centres report broadly equivalent operative times, operative blood loss and post-operative morbidity without significant differences to laparoscopic approaches, although the technical benefit of the robotic endo-articulated wrists were repeatedly emphasised as a partial solution to the difficulties involved with postero-superior segment resections [10, 20, 27, 28]. Furthermore, the use of robotic tremor filtration and gain reduction adjustments were reported to facilitate a greater degree of parenchymal

**17**

*Robotic Liver Surgery*

*DOI: http://dx.doi.org/10.5772/intechopen.99123*

anatomical wedge resections.

forward minor hepatectomies [7].

**4. Oncological outcomes**

**4.1 Hepatocellular carcinoma (HCC)**

sparing surgery and finer hilar or hepato-caval dissection, technical feats which can be challenging in the laparoscopic setting, potentially reducing requirement for conversion to open [27, 29]. These studies are retrospective, and while some include propensity score matching, prospective randomised controlled trial data is lacking. Results from the Dutch ORANGE-SEGMENTS trial investigating the role of open vs. laparoscopic postero-superior liver segmental resection and results are awaited, but to date no such trials are ongoing in regard to robotic non-anatomical and

Left lateral sectionectomy consists of the resection of hepatic segments II and III. The minimally invasive approach has become standard of care for this minor resection with comparative ease of access to the left lateral section, a relatively distant relationship to major vasculature and often minimal difficult mobilisation requirement leading this hepatic resection to be considered one of the more straight

A small number of retrospective studies have aimed to compare the laparoscopic to open approach in left lateral sectionectomy [30–32]. These studies compared a small number of robotic left lateral sectionectomies with retrospective laparoscopic approaches, finding broadly similar results, with no significant differences in operative blood loss, clinical outcomes or operative time, although increased operative costs. A further study, which examined a subgroup of more complex left lateral sectionectomy, with BMI >30, larger tumours or closure operative proximity to major vasculature, reported a significant reduction in operative blood loss, although no significant difference in the overall study group [33]. These results led authors to conclude that the laparoscopic approach to left lateral sectionectomy should remain the standard of care, although it is notable that while gold standard, the only randomised controlled trial comparing laparoscopic vs. open left lateral sectionectomy, ORANGE-II, failed to show a significant difference in outcome when compared the laparoscopic to open approach to left lateral sectionectomy [34]. This result was, in part, due to premature trial cessation due to slow trial recruitment, perhaps reflecting the board uptake of minimal access approach to left lateral sectionectomy. It remains possible that with evidence of clinical non-inferiority of robotics, enthusiastic uptake may further popularise the robotic approach in a similar fashion.

Given that liver resections are predominantly carried out for malignant pathology, oncological standards such as resection margins, lymph node yields, recurrence and disease free survival are the critical outcomes against which robotic hepatectomy should be evaluated. To that end, we have recently published a review of the literature and found robotic liver surgery to be equivalent with regards to the completeness of the resection margin (96% R0) [35]. Although there are a limited number of studies reporting longer term oncological outcomes such as recurrence

HCC is the predominant malignancy for which a robotic approach has been utilised, with 40% of the cases published in the literature indicating this as the underlying indication [22]. Three studies have examined the longer term oncological outcomes following robotic hepatectomy in this cohort and found the oncological outcomes to be comparable. Two of these studies compared robotic surgery to open resection and reported a similar 3 year disease free rate at 64% (Lim et al) and

and disease free survival, the results so far have been promising.

### *Robotic Liver Surgery DOI: http://dx.doi.org/10.5772/intechopen.99123*

*Latest Developments in Medical Robotics Systems*

complication rate [22].

logical outcomes [23].

survival rate [24, 25].

in larger, prospective studies.

**3.2 Minor resections**

tive access difficult [12].

critical care admission, 90 day re-admission rate and a similar length of stay and

The robotic approach has also been shown to be feasible for simultaneous resection of a colorectal primary malignancy and the associated liver metastasis. Analysis of a small number of major hepatic resection with synchronous colorectal resection, demonstrated robotic resection to have acceptable morbidity and onco-

The robotic approach has also been considered as an alternative to open surgery for hepatectomies requiring more extended resections and or biliary reconstructions. Outcomes published by 2 specialist centres demonstrated the robotic approach as a safe and feasible alternative to open surgery for hilar cholangiocarcinoma. However whilst technically feasible and safe, the results did not demonstrate equivalence to open surgery. Indeed they reported longer operative times and a higher estimated blood loss relative to open surgery. Furthermore, robotic resection was associated with poorer oncological outcomes with a lower recurrence free

Given the relative infancy of robotic innovation within the field of minimally invasive surgery, it is perhaps unsurprising that the literature around major robotic liver surgery is somewhat limited. The utility of a laparoscopic approach to major hepatectomy is only presently under investigation and any advantages relative to open surgery remains unestablished. Within this context, it is unclear if open or laparoscopic surgery should be the standard against which robotic surgery is held. At present, level II and III evidence suggests that robotic surgery is safe, feasible, and certainly non inferior to laparoscopic or open surgery. However it remains uncertain if this will translate to clinically significant short and long term outcomes

Minor hepatic resections, a category encompassing non-anatomical wedge resections, left lateral sectionectomies, segmentectomies and bisegmentectomies, are the most commonly performed minimally invasive hepatic operative interven-

While the evidence discussed above suggests the multitude of technical advantages as well as non-inferiority of the robotic approach to major hepatic resections, it is pertinent to critically examine the role of robotic surgery in minor resections if aiming to confer improved operative outcomes to the greatest number of patients. In keeping with the increasing trend for parenchymal sparing liver resection, non-anatomical and anatomical wedge resections are the mostly commonly performed robotic liver minor resection [10]. Indeed, a minimal access approach to resect only small amounts of hepatic tissue seems logical considering the morbidity associated with large abdominal incision; a position supported by international consensus in 2008 [26]. Particular difficulties exist, however, when performing laparoscopic in the postero-superior segments of the liver where a combination of the costal margin and rigidity of laparoscopic instruments conspire to make opera-

A number of robotic minor resection cases series from enthusiast centres report broadly equivalent operative times, operative blood loss and post-operative morbidity without significant differences to laparoscopic approaches, although the technical benefit of the robotic endo-articulated wrists were repeatedly emphasised as a partial solution to the difficulties involved with postero-superior segment resections [10, 20, 27, 28]. Furthermore, the use of robotic tremor filtration and gain reduction adjustments were reported to facilitate a greater degree of parenchymal

tions in both the laparoscopic and robotic settings [10, 17].

**16**

sparing surgery and finer hilar or hepato-caval dissection, technical feats which can be challenging in the laparoscopic setting, potentially reducing requirement for conversion to open [27, 29]. These studies are retrospective, and while some include propensity score matching, prospective randomised controlled trial data is lacking. Results from the Dutch ORANGE-SEGMENTS trial investigating the role of open vs. laparoscopic postero-superior liver segmental resection and results are awaited, but to date no such trials are ongoing in regard to robotic non-anatomical and anatomical wedge resections.

Left lateral sectionectomy consists of the resection of hepatic segments II and III. The minimally invasive approach has become standard of care for this minor resection with comparative ease of access to the left lateral section, a relatively distant relationship to major vasculature and often minimal difficult mobilisation requirement leading this hepatic resection to be considered one of the more straight forward minor hepatectomies [7].

A small number of retrospective studies have aimed to compare the laparoscopic to open approach in left lateral sectionectomy [30–32]. These studies compared a small number of robotic left lateral sectionectomies with retrospective laparoscopic approaches, finding broadly similar results, with no significant differences in operative blood loss, clinical outcomes or operative time, although increased operative costs. A further study, which examined a subgroup of more complex left lateral sectionectomy, with BMI >30, larger tumours or closure operative proximity to major vasculature, reported a significant reduction in operative blood loss, although no significant difference in the overall study group [33]. These results led authors to conclude that the laparoscopic approach to left lateral sectionectomy should remain the standard of care, although it is notable that while gold standard, the only randomised controlled trial comparing laparoscopic vs. open left lateral sectionectomy, ORANGE-II, failed to show a significant difference in outcome when compared the laparoscopic to open approach to left lateral sectionectomy [34]. This result was, in part, due to premature trial cessation due to slow trial recruitment, perhaps reflecting the board uptake of minimal access approach to left lateral sectionectomy. It remains possible that with evidence of clinical non-inferiority of robotics, enthusiastic uptake may further popularise the robotic approach in a similar fashion.
