Elective robotic partial colon and rectal resections: series of 170 consecutive robot procedures involving the Da Vinci Xi robot by a community general surgeon

Robotic colorectal procedures may overcome the disadvantages of laparoscopic surgery. While the literature has multiple studies from specialized centers, experience from general surgeons is minimal. The purpose of this case series is to review elective partial colon and rectal resections by a general surgeon. 170 consecutive elective partial colon and rectal resections were reviewed. The cases were analyzed by type of procedure and total cases. The outcomes analyzed were procedure time, conversion rate, length of stay, complications, anastomotic leak, and node retrieval in the cancer cases. There were 71 right colon resections, 13 left colon resections, 44 sigmoid colon resection sand 42 low anterior resections performed. The mean length of procedure was 149 min. The conversion rate was 2.4%. The mean length of stay was 3.5 days. The percentage of cases one or more complications was 8.2%. There were 3 anastomotic leaks out of 159 anastomoses (1.9%). The mean lymph node retrieval was 28.4 for the 96 cancer cases. Robot partial colon and rectal resections on the Da Vinci Xi robot can be completed safely and efficiently by a community general surgeon. Prospective studies are needed to demonstrate reproducibility by community surgeons performing robot colon resections.


Introduction
Since the first laparoscopic colon resection described in the early 1990s, several factors led to the slow adaption of laparoscopy in colorectal surgery. These included technical difficulty, the lack of standardized technique, the adequacy of oncologic resection, concerns about early local and port site recurrences, longer operative times, and increased cost [1]. By 2012, 43.5% of only colon resection a were completed laparoscopic [2]. Robotic assisted laparoscopic surgery has been proposed to address some of the challenges associated with traditional laparoscopy.
Over the last 10 years, the use of robotic surgery among general surgeons and their specialties has increased. One study revealed an increase use of robotic surgery for all general surgery procedures from 1.8% in 2012 to 15.1% in 2018 [3]. The articulating wrists of the instruments, the improvement of the staplers and vessel sealers, the three dimensional visualization/improved clarity of the camera, as well as the ergonomic features make robotic surgery attractive. Another potential benefit of robotic surgery is decreased likelihood of conversion to open surgery. One disadvantage of the robot platform, is that it is costlier than traditional laparoscopy [4]. This may be due to the cost of the robot and instruments, as well as potentially longer OR times. Proponents of robot colectomy say that the cost is realized with decreased length of stay, although studies are conflicting. One study showed similar operative times as well as length of stay [5]. Another case matched study in 2021 showed significantly increased operative times, but these decreased with further experience [6]. Another advantage of the robot is that it may be easier to construct an intracorporeal anastomosis, which may reduce the handling of the tissues compared to extracorporeal anastomosis. Less manipulation and mobilization may help decrease the risk of ileus, and decrease the time of return of bowel function. A comparative study in 2015 showed a statistical significant earlier return of flatus in patients undergoing robot right colon resections compared to the laparoscopic group [7].
While the literature is full of studies from academic colorectal surgeons, reports examining robotic colon resection by general surgeons are sparse. With a large portion of colorectal resections being completed by general surgeons, it seems important to examine if the results from academic centers can be reproduced by general surgeons. We wanted to examine the first 170 elective robotic partial colectomies by a single community surgeon on the Da Vinci Xi and compare to published data from specialized centers.

Methods
IRB exemption was obtained prior to the review. From February 2018 through June 2022, we reviewed the charts of all the elective robotic partial colon and rectal resections attempted by a single general surgeon in practice at St. Mary's Medical Center in Huntington, WV. The facility is a 293 bed regional medical center for the southern part of West Virginia. The cases reviewed included right colon resections, left colon resections, sigmoid colon resections, and low anterior resections. We excluded total colectomies, abdominoperineal resections, and ileocolectomies because of relatively low volume for these cases. We also excluded urgent or emergent procedures due to differences in disease processes and indications for surgery. There were 170 robotic partial colon and rectal resections included in the review. We analyzed type of procedure, indication for procedure, length of time for the procedure, conversion to open rate, hospital length of stay, total complication rate, anastomotic leak rate, 30-day complication rate and the number of lymph nodes analyzed for the cancer procedures.
For all the colon and rectal resections, we accessed the abdominal cavity using the Veres needle, and established pneumoperitoneum. We placed 4 ports in the abdomen that varied in location based on the location of the resection. Extraction of all specimens was completed through a wound protector after extending one of the port site incisions.
For the right colons, the ileocolic pedicle was isolated and transected at the base using a robotic vascular stapler. Lateral mobilization of the colon and hepatic flexure were then completed. We finished transection of the mesentery using a vessel sealer, followed by transection of the terminal ileum and proximal transverse colon using the robotic staplers, completing the resection. We checked perfusion of the ends using fluorescence imaging after intravenous injection of isocyanide green. We then performed an isoperistaltic ileocolic anastomosis using the robotic stapler, closing the common enterotomy with an absorbable v-lock suture in 2 layers.
For left colon, sigmoid colon resections, and low anterior resections, the colon was mobilized. The splenic flexure was mobilized in all cases. Depending not the indication, the inferior mesenteric artery was transected at its base using a vascular stapler. The mesentery was transected using vessel sealer. The proximal and distal resections of the colon was completed with a robot stapler. We used fluorescence imaging to assess the ends prior to completion of the anastomosis. If an anastomosis was constructed, it was either done in a side-to-side isoperistaltic colon-to-colon anastomosis or a colorectal end-to-end anastomosis using a circular stapling device. We performed a leak test on the anastomosis by insulating air with a bulb syringe while submerging the anastomosis in irrigation fluid.

Right colon
There were a total of 71 robotic right colon resections. The case distribution included the following: 50 cases for cancer, 16 cases for benign polyps, 1 case for appendices cancer, 1 case for lipomatous lesion of ileocecal valve, 1 case for colitis, 1 case for ulcer/mass, and 1 case for Crohn's disease. The mean age was 70 years-old (range 32-90). There were 26 males and 46 females. The mean BMI was 31.5 (range 16.3-56.2). The mean operative time was 135 min (range 75-307). There were 0 conversions to open procedure. The mean length of stay was 4.1 days (range 2-24). There were 5 complications or 7.0% of cases. The complications included 2 atrial fibrillation, 1 postoperative ileus, 1 anastomotic leak, and 1 MI. There were 71 anastomoses constructed. The anastomotic leak rate with the one leak was 1.4%. There was a mean lymph node retrieval of 28.5 (range 8-64) on the 50 cancer cases.

Left colon
There were 13 left colon resections. The case distribution included the following: 10 cases for cancer, 2 cases for colitis, and 1 case for a benign polyp. The mean age was 64 years (range 40-88). There were 6 males and 7 females. The mean BMI was 31.0 (range 19.3-48.0). The mean operative time was 180 min (range 107-309). There were zero cases converted to open. The mean length of stay was 2.9 days (range 2-9). There was 1 complication of a postoperative ileus for a complication rate of 7.7%. Of the 13 anastomoses created, there were no anastomotic leaks. There was a mean lymph node retrieval of 29.2 (range 21-42) for the 10 cancer cases.

Sigmoid colon
There 44 robotic sigmoid colon resections. The case distribution included the following: 31 cases for diverticulitis, 12 cases for cancer, and 1 case for benign stricture from colitis. The mean age was 68 years-old (range 23-89). There were 28 males and 16 females. The mean BMI was 32.9 (range 17.8-53.2). The mean operative time was 137 min (range 79-262). There were 3 conversions out of the 44 cases with a conversion rate of 6.8%. The mean length of stay was 2.9 days (range 1-13). There was only 1 complication of pneumonia making the complication rate 2.3%. There were 42 anastomoses created and 2 end colostomies. There were no anastomotic leaks. The mean lymph node retrieval was 28.0 (range 13-48) for the 12 cancer cases.

Low anterior resection
There were 42 robot low anterior resections completed. The case distribution included the following: 23 cases for cancer, 17 cases for diverticulitis, and 2 cases for benign polyps. The mean age was 65 years-old (range 27-87). There were 15 males and 27 females. The mean BMI was 30.4 (range 15.3-46.5). The mean operative time was 180 min (range 96-324). There was 1 conversion to open or 2.4% of cases. The mean length of stay was 3.6 days (range 2-60). There were 7 complications out of the 42 cases or 16.7%. The complications were two anastomotic leaks, three pelvic abscesses, one ileus, one multi system organ failure/death. The mortality rate in these cases was 2.4%. There were 33 anastomoses, nine end colostomies, and one loop ileostomy. There were 2 anastomotic leaks out of 33 anastomoses created or 6.1%. The mean lymph node retrieval for the 23 cancer cases was 32.7 (range 8-87).

Total
In total, there were 170 robotic partial colon and rectal resections. The case distribution is as follows: 95 cases for cancer, 48 cases for diverticulitis, 19 cases for benign polyps, 3 cases for colitis, 1 case for Crohn's disease, 1 case for appendiceal cancer, 1 case for an ulcer/mass, 1 case for benign stricture, and 1 case for benign lipomatous lesion of ileocecal valve. The mean age was 65 years-old (range 23-90). There were 75 males and 95 females. The mean BMI was 31.5 (range 15.3-56.2). The mean operative time was 149 min (range 75-324). There were 4 conversions to open or 2.4%. The mean length of stay was 3.5 days (range 1-60). There were a total of 14 complications or 8.2%. The mortality rate for all cases was 0.59%. There were 159 anastomoses, 11 colostomies, and 1 loop ileostomy. The anastomotic leak rate was 1.9% or 3 cases out of 159 anastomoses. The mean lymph node retrieval for the 96 cancer cases was 28.4 (range 8-87).

Discussion
In this review, we report the first 170 elective robotic partial colon and rectal resections by a community general surgeon on the Da Vinci Xi robot. We report efficient mean length of procedure, low conversion rate, low complication rate, low anastomotic leak rate, low length of stay, and satisfactory lymph node yield in oncologic cases. These outcomes are equivalent to published data on both robotic colon resections as well as traditional laparoscopic cases.
Many studies show increased operative time with the robotic approach. In our series, the mean operative time for all cases was 149 min. In a large study in 2016 comparing laparoscopic colon resection a to robotic colon resections, the mean operative time of the robot colectomy was 233 min, whereas the laparoscopic colectomy was 180 min [8]. In another study, operative times were also similar between the laparoscopic vs. the robotic approach for colon resections (150.5 vs 169.5 min) [5]. Operative times specifically have been reported for right colon resection to be 165.31 min ± 43.08 in the laparoscopic group vs. 207.38 min ± 189.13 in the robot group [9]. A randomized trial in 2012 showed the duration of surgery was longer in the robot group (195 versus 130 min; P < 0·001) [10]. Our mean operative time for robotic right colon resection a was 135 min. Operative times for laparoscopic vs. rectal resections have been reported at 197.0 min and 231.5 min, respectively [5]. We reported mean operative time on robot low anterior resections as 180 min. Overall, our mean operative times were more comparable to the laparoscopic times reported, and more efficient than the robot times reported.
The conversion rate for all cases in this series was 2.4%. In a study comparing laparoscopic vs. robotic colon resections, the conversion rates were 10.3% and 12.2%, respectively [8]. In rectal cancer surgery, the conversion rate reported was 2.1% for robotic cases and 9.6% for laparoscopic cases [11]. We had conversion rate for low anterior resections of 2.4%. We had no conversions with right colon cases. In as systematic review by Waters et al. showed conversion rates less with robotic right colon resections (0-3.9%) versus laparoscopic right colon resections (0-18%) [12].
We reported an overall complication rate of 8.2%. The rates in the literature varies for colorectal surgery complications. A French study of 1421 colorectal surgery patients had a morbidity rate as high as 35% [13]. Longo et al. showed at least one or more complications in 1639 patients out of 5853 or 28% [14]. Specifically for robotic colectomy, a study of 1040 patients undergoing surgery for colorectal cancer, the overall, severe, local, and systemic complication rates were 12.2%, 2.4%, 8.8% and 3.5%, respectively [15].
Anastomotic leaks, a serious complication, have been reported with varying rates in the literature. In our study, there were 3 anastomotic leaks out of 159 anastomoses created or 1.9%. Miller et al. reported comparable leak rates between laparoscopic and robotic colon resections (3.1 vs 3.4%) [8]. In a large study of 13,684 partial colectomies, the overall anastomotic leak rate was 3.8% [16]. Our highest rate of leaks was 6.4% in the patients undergoing low anterior resection. A study citing 15 other studies reported anastomotic leak for low anterior resections varies from 0 to 36% [17].
One of the main reasons for the adoption of minimally invasive colorectal surgery is the decreased length of stay. In our study the mean length of stay was 3.5 days. Nolan et al. reported length of stay of 4 days for both the robot and laparoscopic colon and rectal resections [5]. In a comparative study of over 2400 minimally invasive colon resections, the mean length of stay was 4.8 days compared to 6.3 days, and was statistically significant [18]. One of the surprises that in the right colon subgroup the mean length of stay of 4.1 days, which was higher than the rest. There were four patients in the right colon subgroup that were outliers with higher length of stay due to complications. When these patients were removed the length of stay for right colon resections fell to a mean of 2.86 days. Tschann et al. reported average length of stay was 5.31 days with robotic cases and 6.15 days with laparoscopic cases [9].
The American Joint Committee on Cancer staging for cancer of the colon, a minimum of 12 lymph nodes (LN) has to be sampled for accurate staging. There may be improved survival with increased lymph node yield. One study concluded that lymph node yield of 20 or more was associated with better survival outcomes [19]. Our mean lymph node yield for the resections for cancer was 28.4.
There are very few colorectal surgeons in West Virginia. Despite being a referral center in the state, our facility has no colorectal surgeons. Also, many patients in our state do not want to travel out of state to larger, specialized centers. Due to this, much of colorectal surgery volume is addressed by general surgeons.
The short-term measures of successful robotic colon and rectal resections in this study are at least equivalent, if not better than published reports. Long term outcomes were not addressed in this review. Also, cost-outcomes were not analyzed. There are few randomized controlled trials in the current literature with regards to outcomes of robotic colorectal surgery.
Robot partial colectomy on the Da Vinci Xi robot can be completed safely and efficiently by community general surgeon for both benign and malignant disease compared to published standards. More prospective studies are needed to demonstrate adoption and reproducibility by community surgeons performing robot colon resections.
Author contributions Both authors contributed the entire process of preparing this manuscript.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflict of interest
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.