The use of robotics in colorectal surgery has been steadily increasing. However, longer operating times due to set up and docking and increased costs has limited its widespread adoption [6]. Moreover, additional training is required for staff to operate the machinery, and there is a learning curve for surgeons learning this new platform. However, more current studies have demonstrated significant reductions in length of stay, conversion to open surgery rate, and hospital costs for surgeons performing a high volume of robotic surgery [4]. A recent systematic review of robotic resections in diverticular disease demonstrated that robotic surgery for diverticular disease was associated with a reduced conversion to open surgery, but a longer operating time as compared to laparoscopic surgery [9]. In another study comparing outcomes of robotic versus laparoscopic colorectal surgery for both benign and malignant conditions, performed by surgeons experienced in both robotic and laparoscopic procedures, they found no statistical difference in length of stay, time to return of bowel function, and time to discontinuation of patient-controlled analgesia [10].
Robotic rectal surgery has advantages over laparoscopic surgery in terms of reducing length of hospital stay (LOS); translating to potential cost-savings, and reduced risks of hospital-associated complications for patients [4]. Studies have demonstrated a less complicated post-operative course with robotic surgeries, and a more rapid bowel recovery, which led to significantly shorter length of stay [11], and a quicker return to function post-operatively. In our study, there was a significantly shorter LOS after robotic surgery (p = 0.024). This was consistent with findings from Crippa et al. [12] who also reported a significantly shorter LOS in the robotic group when compared with the laparoscopic group in rectal cancer surgery; 21.45% in the robotic group had a LOS ≥ 6 days compared to 43.11% in the laparoscopic group (p < 0.001). Interestingly, robotic surgery was the only independent protective factor from prolonged LOS [12]. Patients undergoing robotic surgery were 38% less likely to remain in hospital for 6 days or more compared to laparoscopic surgery [12].
Gass et al. [13] compared robotic and laparoscopic left-sided colectomies and demonstrated no statistical difference in anastomotic leak rates or intraoperative complications between both groups [13]. This is similar to our study findings where there were only 6 patients who had post-operative complications and there was no significant difference (p = 0.609) in the complication rates between the two groups. None of the patients in our cohort had anastomotic leakages.
30-day mortality rates are reportedly low in both elective laparoscopic and robotic surgery for rectal cancer. Crippa et al. [12] showed both techniques had similar rates of 30-day mortality. Similarly, Myrseth et al. [14] also demonstrated that 30-day mortality did not differ between robotic-assisted resection and laparoscopic resection, which is consistent with other large studies [14]. This was similar in our study whereby there was no 30-day morbidity or mortality.
Longer operating times is one of the reasons for hesitancy in the uptake of robotic surgery. These are generally associated with a greater risk of complications including complications from prolonged general anaesthesia, bleeding and venous thromboembolism; shorter operating times have been a goal in improving surgical outcomes [15]. In the study by Gass et al. [13], operating time was significantly longer in robotic group compared to laparoscopic group for patients with diverticular disease for left-sided colectomies [13]. A confounding factor in that study for the longer operative time was proposed to be the use of the da Vinci Si® platform at the initial stages [n = 29 (16.2%) da Vinci Si® vs. n = 150 (83.8%) da Vinci Xi®] [13]. The newer da Vinci Xi® was subsequently easier to dock and set up. In the systematic review by Larkins et al. [9], operating time was longer with a robotic approach (p = 0.03) compared to laparoscopic approach [9]. Our study however demonstrated no significant difference in operating time in the laparoscopic and robotic anterior resection group (p = 0.095). Moreover, our study had included the robotic docking time as part of the total robotic operating time, and as such, we can deduce that the actual operating time was in fact shorter in the robotic group than in the laparoscopic approach. This could be attributed to better visualisation and articulating instruments with the robotic platform, especially when approaching a phlegmonous diverticular segment, as well as the experience of the colorectal surgeon who was already well versed in both laparoscopic and robotic surgery.
In another study by Parascandola et al. [16] describing a single surgeon’s experience in performing robotic-assisted low anterior resections, the mean operating time was 286 min, with a significant reduction in mean operating time from the first to the fourth quartile of cases, suggesting that the learning curve was reached after 55–65 cases.[16] Similar to the study by Gass et al. [13], our initial operating platform was also da Vinci Si®, which then progressed to the da Vinci Xi®. However, there was no significant reduction in mean operating time throughout our cases, once again suggesting that in experienced hands, setting up and docking of robot becomes much less arduous and requires minimal additional time. Some methods to improve operative time in robotic surgery include standardisation of docking steps and repetitive training with identical teams to reduce operative time [13]. One study found that operating times were almost identical in right-sided colectomy group where undocking the robot is not a requirement [10]. However, during left-sided robotic colon resections where robot repositioning was a mandatory step, there was a significant difference of approximately 30 minutes in favour of the laparoscopic group [10]. However, with the development of the integrated table motion for the da Vinci Xi® and variations in port placements, more flexibility and less re-docking may be required, which significantly reduces operating time [17].
Surgical experience plays a large role in the likelihood of conversion to open surgery. In the study by Kowalewski et al. [18] where surgeons had performed at least 100 robotic procedures, the odds of conversion were significantly lower with the robotic approach, independent from the number of laparoscopic procedures performed [18]. Conversion to open surgery is usually associated with more complications, longer hospital stays and poorer long-term outcomes [6, 14]. Many studies have shown that robotic surgery is associated with significantly lower conversion rates as opposed to laparoscopic surgery in rectal cancers [4, 12, 14, 19]. Our study also reflects this with a 0% conversion to open in the robotic group. This could be because robotic surgery allows improved access to difficult to reach regions such as the narrow pelvis. Laparoscopic surgery on the other hand does not have this advantage and access to areas such as a narrower pelvis in the obese are more difficult [4, 20]. In the ROLARR trial comparing robotic and laparoscopic rectal cancer surgery, the conversion rate to open surgery was not statistically significant. However, subgroup analysis showed that the conversion rate in the laparoscopic group was significantly higher in male and obese subpopulations than in the robotic group [7].
We understand that there will be a learning curve when learning a new technology, however with consistent volume and practice, we believe that the time taken for robotic surgery will be similar to that of laparoscopic surgery, if not shorter due to the precision and vision that the robotic platform provides in a difficult diverticular phlegmon or fistula resections.
Limitations
Our study findings should be interpreted in the context of the following limitations. Due to the retrospective nature of the analysis, there is potential of confounding by unmeasured factors. The number of the study is low, and results of this study represent a single surgeon and therefore may not be generalizable to other surgeons who have varying experience in either laparoscopic or robotic surgery. We acknowledge that there is a learning curve involved for each surgeon to become an experienced operator in each approach. Further research exploring the learning curve of surgeons and larger patient cohort is needed to confidently state the non-inferiority of each approach.