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Kavalukas et al. Mini-invasive Surg 2020;4:61 I http://dx.doi.org/10.20517/2574-1225.2020.71 Page 3 of 8

Another comprehensive study of 2,735 patients showed a significantly higher rate of conversion in the
laparoscopic compared to robotic group. This was found throughout the general cohort as well as in rectal
[12]
specific procedures, which had a conversion rate of 7.8% vs. 21.2%, respectively (P < 0.001) . While these
studies boast large sample sizes, the two arms were unevenly matched in terms of number of patients,
which may have affected the results. This issue is common throughout the literature on this topic, given
the novelty of robotic surgery. A meta-analysis of four randomized controlled trials (the highest quality
evidence available), found a significant difference in conversion rates of patients undergoing colorectal
resections for cancer. The robotic procedures had lower rates of conversion to open (1.82%) vs. laparoscopic
[13]
procedures (9.48%), P < 0.04 .

Upon review of this data, one can safely argue that robotic procedures are associated with lower rates
of conversion compared to laparoscopic surgeries. However, it should be noted that there are many
confounding factors which may affect these results. Patients with a hostile abdomen, advanced tumours,
or other considerations may be planned to undergo laparoscopic instead of robotic surgery if the surgeon
is anticipating a high likelihood of conversion. Other scenarios may have presented with unexpected
intraoperative findings that would have required the case to be converted no matter which modality was
used.

Operative time
Successful performance of surgery is not measured by the time required to perform the task. However,
increased operative time correlates with many adverse perioperative outcomes. Data collected across
all surgery specialties demonstrates that operative time was 30 min longer in patients with surgical site
[14]
infections than in those without . Increased operative time has also been shown to result in higher rates
of ileus and length of stay [15,16] .

Advocates for laparoscopic surgery often attribute the time needed to dock the robot as a drawback to
robotic surgery. The progress of the surgery comes to a halt during this time, particularly with procedures
spanning two abdominal quadrants that require a second docking of the robot. Robot docking times have
a reported mean of 3-11 min [17,18] . Longer operative times in robotic compared to laparoscopic surgeries
were reported in earlier studies performed between 2010-2014 [9,12] , however, later studies have found no
difference in times comparing laparoscopic with robotic colorectal resections [11,19] .

Global utilization of the robot has enabled an international meta-analysis of 22 studies comparing operative
times, demonstrating a significant difference in favour of laparoscopic over robotic procedures . Surgeon
[20]
experience, case volume, and consistency of the operative team are major factors affecting operative
efficiency for both methods. A more detailed analysis of operative time will be discussed below with an
overview of the learning curve.

Cost
Laparoscopic instruments are repeatedly reusable, apart from energy devices and staplers which are
discarded after one operation. Robotic instruments are calibrated for a finite number of uses per instrument;
typically, after ten operations the instrument must be replaced. However, the individual instruments
contribute to only a small part compared to the cost of using the platform. It is difficult to capture cost
differences regarding the procedure itself, as many studies utilize the total cost of hospitalization as their
[21]
endpoint. Alharthi et al. looked at sigmoid colectomies and found a cost difference of $45,057 vs. $57,871
in favour of laparoscopic procedures. This margin has been repeatedly demonstrated on subsequent studies
including a meta-analysis of randomized controlled trials, with a reported average higher cost of $8,000-
$10,000 for robotic procedures [22,23] .