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Chouhan et al. Mini-invasive Surg 2018;2:18 I http://dx.doi.org/10.20517/2574-1225.2018.40 Page 3 of 7

A B

Figure 1. (A) The left neurovascular bundle (arrows) attached to the left seminal vesicle (SV) is dissected from the rectum (R); (B) the
right neurovascular bundle (arrows) attached to the right SV is dissected from the R

each). In multivariate analyses, the robotic approach was a significant positive prognostic factor for overall
survival and cancer-specific survival (P = 0.0040, HR = 0.333; P = 0.0161, HR = 0.367).

Lower conversion rates with robotic rectal surgery
As shown in a classic trial, higher conversion rates are associated with poor oncological outcomes and higher
mortality. A meta-analysis comparing robotic surgery with laparoscopic surgery found robotic surgery to
[19]
be associated with a lower conversion rate than open surgery , a finding seen in two other studies [20,21] .
This potentially may allow the surgeon to complete many challenging rectal cancer cases using MIS with
similar oncological outcomes. Data from the robotic vs. laparoscopic resection for rectal cancer (ROLARR)
trial have shown that robotic surgery reduced the conversion rate in obese males with low rectal cancer, a
[22]
challenging group for laparoscopic surgery .

Shorter learning curve with robotic surgery
The learning curve for laparoscopic colorectal surgery ranges between 30-70 cases . A robotic platform
[23]
which emulated open surgery with the advantage of a 3-dimensional magnified view, using articulating
instruments (as compared with the straight instrument in laparoscopy) and better ergonomics has been
shown to have a shorter learning curve, at some 20 cases [24,25] . However, the loss of haptic feedback with
robotic surgery may confound the robotic learning curve. An initial learning period of 30-40 cases and
experience in visual cues lead to the second phase, where surgeons start taking on more complex cases.

Better chance for nerve preservation
Studies comparing sexual dysfunction between laparoscopic surgery and open surgery have shown that
sexual function is significantly impaired after laparoscopic surgery [26-28] . However, robotic surgery has shown
improved post-operative sexual dysfunction and earlier functional recovery, compared with laparoscopic
[29]
surgery . Improved sexual and urinary functions after robotic surgery are reflections of better nerve
visualisations using a 3-dimensional magnified robotic platform [Figure 1].

Ability to assess vascularity of anastomosis
It is well known that distal perfusion is one of the main technical factors that affect the leak rate . Measures
[30]
such as bleeding from marginal vessels, mesenteric vessel pulsation, a lack of distal end discolouration and
[31]
negative leak tests are all unreliable and do not help predict postoperative leaks . Indocyanine green (ICG)
which is absorbed near infrared light and detected by a robotic NIR camera system helps assess the distal
[32]
bowel vascular supply and decrease anastomotic leak . In one study, the use of ICG has shown a 60%
[33]
reduction in the leak rate . It also visualizes unusual vascular anatomy such as the Arc of Riolan . Use of
[35]
[34]