Right colectomy from open to robotic — a single-center experience with functional outcomes in a learning-curve setting

Right colectomy (RC) with complete mesocolic excision (CME) for carcinoma of the ascending colon is a frequently performed standard procedure in general surgery. Several different techniques are known for oncologic RC with CME, ranging from conventional open surgery (COS) to hybrid or total minimally invasive approaches with different variants of extracorporal or intracorporal techniques for the ileo-colic anastomosis, respectively [1‐3]. Thereby, numerous studies have proven the non-inferiority of minimally invasive surgery in colorectal cancer concerning oncological long-term results compared with COS as the benchmark [4‐7]. Although conventional laparoscopy had broadly been applicated as standard in surgery of the left colon and rectum over the last decades, minimally invasive approaches using conventional laparoscopy are sparsely introduced into clinical routine practice for oncologic resections of the right colon [8‐11]. However, through increasing numbers and availability of robotic programs, growing experiences with, further development in as well as technical advantages of robotic-assisted surgery over conventional laparoscopy [2, 8, 12‐16], minimally invasive robotic approaches for RC are constantly evolving and progressively established in the clinical routine [9, 11, 16‐18]. Although costs of minimally invasive approaches, especially of robotic surgery, are considerably higher compared with COS [11, 17, 19, 20], some evidences exist in the current literature concerning improved postoperative short-term outcome and morbidity, respectively, of patients after minimally invasive RC with CME [11, 17, 18, 20‐24]. Particularly the total minimally invasive approach with intracorporal anastomosis is beneficial considering postoperative pain [25], surgical site infections [22, 26], and complications urging re-interventions [22, 26, 27] and finally results overall in a shorter recovery and decreased postoperative length of hospital stay [22, 25‐29]. After this had been extensively shown in studies and confirmed by systematic reviews and metaanalyses for conventional laparoscopic apporaches [30], current literature reveals further improvements of intraoperative visualization resulting in higher lymph node yield and postoperative patient outcome with growing experiences in minimally invasive robotic surgery for RC with CME [8, 24, 30, 31]. Nevertheless, the beneficial impact of robotic-assisted or total robotic surgery in comparison with COS as the benchmark approach for oncologic RC with CME on postoperative outcome, especially including systemic inflammation, functional bowel recovery, and their association with duration of hospitalization, currently remains elusively. While postoperative bowel dysmotility and paralysis is a temporary physiologic reaction after abdominal surgery, a prolonged state of bowel dysfunction and paralytic ileus is an extraordinary frequent clinical problem in patients after surgery of the right hemicolon [24, 32]. Nonetheless, their pathophysiology is currently not fully understood, but delayed postoperative return to normal bowel function is a major threat for patients, which frequently results in high risk for harmful acid aspiration, impaired patient comfort, and general postoperative outcome and prolongs hospital stay as well as recovery of affected patients and consequently increases public health costs [33‐35].

We herein report the experiences with oncologic RC including CME from a nation-wide benchmark center for robotic colorectal surgery [36] with regard to postoperative bowel recovery and patient outcome. Before implementation of the robotic program at that institution, RC was approached by COS. During the learning curve of robotic surgery, the complex procedure of oncologic RC with CME was initially performed by a robotic-assisted approach with extracorporal ileo-colic anastomosis and was finally converted to total minimally invasive robotic surgery with intracorporal anastomosis, giving the opportunity to compare both minimally invasive approaches with standard COS in the era of robotic surgery.

The present study describes beneficial effects of the total robotic approach on postoperative bowel recovery and general patient outcome during the learning curve of robotic RC with CME. Since implementation of the robotic surgery program, the institution had been evolved to a nation-wide benchmark center for robotic colorectal surgery [36]. However, we came from conventional open surgery as the generally accepted standard procedure and went directly to robotic surgery for oncologic RC without taking the detour via conventional laparoscopy. Hence, a comparison of conventional laparoscopy directly with robotic surgery was not performed herein, which might be a weak limitation of the present study. However, as our experience and data from the recent literature proof as well as nationwide research in medical care show, robotic surgery allows consistent results even for surgeons with no prior experience in minimally invasive, conventional laparoscopic surgery after adequate and structured training [4‐7, 9, 11, 16, 37]. Although non-inferiority was proven by randomized trials early in 2005 and 2007 for laparoscopic compared with conventional open colorectal resections for cancer, conventional laparoscopic approaches did not reach general acceptance in many European countries [4‐7, 9, 37]. Especially the rate of laparoscopically performed right colectomies remains low [9] with an overall increasing trend towards robotic surgery [11, 16]. This reflects the situation in many surgical departments, as ours: the decision is made between COS or robotic surgery, but conventional laparoscopy is not considered for oncologic RC. Thereby, the literature reveals for patients after robotic surgery some impactful advantages with respect to relevant clinical outcome parameters moreover laparoscopy [11, 16, 24, 31], including higher lymph node yield during CME and shorter intracorporal hand-sewn anastomosis time due to improvements in ergonomics, handling, and visualization through the robot [8, 12, 31, 38].

Procedure times seem to be an aspect of economic disadvantages of robotic surgery. Although the literature proofs shorter time for intracorporal suturing of the anastomosis during robotic surgery [12, 38], the duration of the total robotic procedure is — in contrast to the data of the present ICA group — supposed being longer compared with conventional laparoscopy and COS [11, 39, 40]. But, there is currently no standardized definition available which data should be recorded for the operation time of robotic surgery and most publications on robotics do not discriminate between port setup time, time-consuming docking, robot time, or assisted time, which includes creation and closure of the minilaparotomy, extraction of the specimen, or different steps of surgery, for example, the time for extracorporal anastomosis as well [8, 41]. Nevertheless, slightly longer operation times in comparison with standard COS (p = 0.044) were only observed in the present study during the initial ECA phase, immediately after introduction of robotic surgery to oncological RC, but not thereafter. Though the operative time was defined in the present study as the continuum from the first incision to complete skin closure and consecutively includes all the previously mentioned surgical steps. Hence, these quite short operation times especially after these initial (ECA) cases might be an effect of the strong two-step learning curve setting described in here. Increases in surgeon experiences and team training are essential to improve performance in robotic surgery [8, 41, 42]. In the present study we started the program with the robotic-assisted approach; thereby the ileo-colic anastomosis was sewn by hand in the conventional manner through a transverse laparotomy (ECA patients). This first step allowed us to get in touch with robotics and to gain sufficient experiences with mobilization of the colon and appropriately approaching the CME, a crucial and difficult-to-perform step in minimally invasive RC [8]. Thereafter we went to the total minimally invasive approach with intracorporal hand-swen anastomosis (ICA patients), which can be safely performed by experienced robotic surgeons [3], as the next step. Although we only saw slight differences in operation times in direct group comparison between COS and ECA, learning curve analysis confirmed these results impressively: significant decrease over time during initial ECA patients, but not anymore thereafter (ECA: r² = 0.107, p = 0.048; ICA: r² = 0.002, p = 0.755; data not shown). However, the duration of operation times in COS patients might reflect a minor limitation of the study through the fact that in the present patient cohort open right colectomies were performed by different surgical teams, including different surgeons (n = 8) at different training levels. Thereby the open procedures were performed together with a well-experienced senior surgeon at least as the first assistant. In contrast, robotic surgeries were performed exclusively by two well-experienced senior surgeons in an experienced team. Nevertheless, by the decrease over time, we conclude that procedure durations approximate the standard COS approach for RC after the initial learning phase. This was the situation for the ICA cohort and, together with the low conversion to open surgery rate in ICA patients (n = 1/56, 1.8%), these data proved the sufficiency of our learning curve setting. However, this learning curve effect was not observed in total lymph node yield through CME over time as a global parameter for oncologic quality of surgical approaches. Both the decrease in operation time and constant lymph node yield over time indicate the efficacy of our learning curve setting, which was accordingly completed during the initial observational period of the present study [8, 14] and allows for the conclusion that the institutional development from COS via ECA to ICA had neither impaired oncologic quality during surgery nor patient safety.

The advantages concerning short-term outcomes of minimally invasive surgery over COS in colorectal surgery are obviously evident and had been extensively shown in the current literature for RC by laparoscopic approaches, whereby oncological outcomes were not inferior [1, 43]. Although operation times of minimally invasive routes were considerably longer in previous literature, beneficial effects of minimally invasive surgery for RC were also reproduced by the robotic approaches in the present study: rate of major morbidity including re-operations, postoperative bleeding, anastomotic complications, and rates of surgical site infections, reflected by longer length of postoperative hospitalization and higher rates in CCI in the COS group [10, 11, 16, 17, 30, 31, 44]. In the recent literature no differences have been shown regarding anastomotic complications, i.e., leackages and bleeding, in comparsion of different types of anastomoses (intracorporal versus extracorporal or hand-sewn versus stapling, et cetera) [3, 45‐48]. Vice versa, the intraabdominal creation of the anastomosis itself, including shorter incision length [49‐51] and alternatives of the extraction site, i.e., Pfannenstiel versus midline or pararectal incisions [26, 50‐52], correlate with reduced rates of surgical site infections [26, 27, 31, 53] and incisional hernia [51, 54] during short-term and long-term follow-up after RC. Furthermore, a lower pain level [50], a shorter duration until normalization of bowel function including a faster food tolerance, and time to passage of first postoperative flatus and stool contribute to improved patient comfort, enhanced patient recovery, and result in shorter length of postoperative hospital stay in patients after total minimally invasive RC with intracorporal anastomosis [26, 27, 49, 50, 52, 55].

Prolonged postoperative bowel dysfunction and ileus observed in up to 30% of the patients are frequent pathologies after RC [24] and cause prolonged food intolerance, significant dyscomfort, and potential severe morbidity for the affected patients [33‐35]. Time to first stool was decided as the surrogate parameter of postoperative bowel recovery in the present study, which allows for comparison with the literature; however core outcome sets for defining postoperative gastrointestinal recovery or prolonged bowel dysfunction and ileus had not been described, yet [56]. Postoperative gastrointestinal dysmotility is a physiologic and temporary reaction following abdominal surgery, but usually returns to normal function rapidly [33, 57]. The pathophysiology of prolonged postoperative bowel dysfunction is uncertainly multifactorial but currently not fully understood [58]. Although the literature previously suggests that intracorporal anastomoses are beneficial regarding the duration of postoperative bowel recovery, our data give some important insights in the pathophysiology of prolonged gastrointestinal dysfunction: neither duration of surgery nor extent of CME with central lymph node harvesting but greater extent of ileo-colic manipulation, higher trauma to the abdominal cavity, and more severe systemic inflammatory response, both might trigger opioid-based pain therapy, contribute to prolonged gastrointestinal dysfunction in the COS and ECA groups (p = 0.0009 and p = 0.020 versus ICA, respectively) [33, 57, 59]. Furthermore, regression analyses clearly demonstrate the harmful effect of gastrointestinal dysfunction on patient outcome: delayed postoperative bowel dysfunction contributes to longer postoperative in-hospital stay especially in patients who underwent COS (r² = 0.187, p = 0.045) for oncologic RC. This was comparable with other severe postoperative complications. These results reveal that the ICA procedure is clinically more effective with regard to postoperative bowel recovery and length of postoperative hospitalization.

Nevertheless, higher initial and running costs, stronger investment in surgical instruments and consumables, and longer operation times lead to ongoing debate if the benefits of robotic surgery justify economic concerns, especially competing with conventional laparoscopy [1, 11, 21, 24]. Aspects, which might finally overcome initial economic burdens, include the optimization of the surgical procedure by decreasing the duration over time through surgical team formation and strong adherence to the learning curve as well as the use of more cost-effective techniques and materials (hand-sewn instead of stapler anastomosis, conventional laparoscopic instead of robotic staplers, reduction of robotic ports). However, the most powerful impact from a clinical and economic view have lower complication rates, faster recovery, and shorter length of in-hospital stay after robotic compared with both COS and laparoscopic RC [11, 16, 20, 24]. Thus, in our study robotic surgery let to a significant reduction in cost-intensive postoperative complications, duration at the intensive care unit, and length of postoperative in-hospital stay by one third from median 12 (COS) to 8 days (both robotic approaches: ECA and ICA, p < 0.01 each in comparison with COS). This might all together turn initial economic disadvantages into a potential benefit and increases the revenue for robotic cases.

In conclusion, the results of this single-center experience demonstrate that implementation of a robotic program for right colectomies with CME is safely feasible even without experiences in conventional laparoscopic surgery in that field. Beginning the learning curve with the robotic-assisted approach and extracorporal anastomosis is approporiate; conversion to total-robotic surgery with intracorporal anastomosis after enough experiences and surgical skills had been acquired provides excellent outcome for the patients. Especially the effects of total minimally invasive robotic surgery on postoperative functional bowel recovery and wound complications positively impact on length of hospitalization and patient comfort. This might overcome economic concerns regarding robotic surgery.