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Page 6 of 10 Sebastián-Tomás et al. Mini-invasive Surg 2019;3:30 I http://dx.doi.org/10.20517/2574-1225.2019.29

described the OS and DFS after a mean follow-up of 29.2 months in the robotic group and 18.7 months in
the laparoscopic group. The OS was 100% in the robotic group and 94.1% in the laparoscopic group. The
DFS was 100% in the robotic group and 88.2% in the laparoscopic group. Studies comparing robotic and
open resections also found non-significant long-term outcomes between them. Five-year DFS was 73.2%
and 69.5% in the robotic and open groups, respectively. Five-year OS was 85.0% in the robotic and 76.1% in
[69]
the open approach .
Functional outcomes
Two trials evaluated the urinary function of using the International Prostate Symptom Score (I-PSS)
[65]
comparing robotic and laparoscopy TME. Lee et al. showed improved urinary continence for robotic
[65]
surgery at 3 months, but there was no statistical difference on I-PSS at 6 or 12 months after surgery .
Erectile dysfunction rates did not differ between robotic and laparoscopic groups (OR, 0.54; 95%CI: 0.19-1.58;
[66]
[64]
P = 0.26) . Somashekhar et al. analyzed erectile dysfunction and retrograde ejaculation using the
European Organization for Research and Treatment of Cancer questionnaire QLQ-C38. A total of 18 %
[70]
[66]
of male patients in the robotic group and 26% in the open group had sexual dysfunction . Li et al.
[70]
published a meta-analysis reporting lesser incidence of urinary retention using robotic TME . The
ROLARR trial evaluated bladder function, male sexual function and female sexual function separately by
using I-PSS, International Index of Erectile Function and Female Sexual Function Index, respectively. This
[26]
study did not find any differences between laparoscopic and robotic surgery after 6-months follow-up .
FUTURE PERSPECTIVES
Fluorescence-guided robotic rectal resection
[74]
Near-infrared (NIR) light (650-900 nm) has optimum characteristics for in vivo imaging , resulting in
higher penetration depth and minimum background auto-fluorescence . Indocyanine green (ICG) is
[75]
the only available fluorophore in the NIR window, it is confined into the vascular compartment through
binding plasmatic proteins presenting low toxicity . The applications of ICG are increasing, especially at
[76]
colorectal cancer surgery. NIR has been used for assessing tissue perfusion and to detect sentinel nodes,
peritoneal carcinomatosis, or liver metastases [77-80] . Anastomotic leak remains as the main complication
in colorectal surgery, ischemia of intestinal stumps constitutes a major risk factor [81,82] . To determine
the viability of the intestinal stumps when performing the anastomosis may decrease the odds of leak
development. The earliest RCT on the subject just showed a reduction (9% vs. 5%), but non-significant,
[83]
of the anastomotic leak rate in the fluorescence arm after colorectal resection . Only two retrospective
studies have been conducted using robotic technology [84,85] .

The “enhanced permeability and retention” effect is the mechanism involved. It reflects the affinity of ICG
towards tumoral and near-tumoral tissue due to neovascularization. Few studies are trying to elucidate
the role of ICG in carcinomatosis, with contrasting results [79,86] . Neoadjuvant therapy with bevacizumab
[87]
decreases the sensitivity of ICG to detect peritoneal metastases of colorectal cancer . Mucinous metastases
cannot be identified with ICG. A recent RCT comparing the use of white light versus NIR and ICG showed
[88]
increasing sensitivity from 80% to 96% . ICG can be alternatively used to improve surgical safety when
marking important structures, as the ureters or the hepatic ducts, and even for tattooing colonic neoplasms
[89]
instead of ink .
Robotic-assisted transanal TME
Over the last few years, the transanal approach gained popularity as seemed to facilitate complex pelvic
dissections. Several studies reported that Ta-TME achieved similar technical success and perioperative
[90]
outcomes than laparoscopic TME, with a lower conversion rate . Recent studies also showed that serious
complications secondary to wrong down-to-up dissection planes were not despicable, same for anastomotic