A propensity score matching study of totally robotic right hemicolectomy versus robot-assisted right hemicolectomy

To compare and analyze the differences in safety, feasibility and short-term efficacy between robot-assisted right hemicolectomy (RARH) and totally robotic right hemicolectomy (TRRH). We collected the information of 184 patients who underwent right hemicolectomy in the Second Xiangya Hospital of Central South University from July 2016 to December 2021. We matched 148 patients (74 with robot-assisted right hemicolectomy and 74 with totally robotic right hemicolectomy) to conduct a retrospective analysis of their clinical outcomes. The incision lengths were 5.14 ± 0.60 cm in the RARH group and 4.74 ± 0.55 cm in the TRRH (p < 0.001). The blood losses were 86.28 ± 52.57 mL in the RARH group and 69.19 ± 44.78 mL in the TRRH (p = 0.035). The operative times were 197.50 min (171.25–242.25) in the RARH group and 160.00 min (145.00–188.75) in the TRRH (p < 0.001). The postoperative hospital stays were 11.18 ± 4.32 days in the RARH group and 9.53 ± 4.42 days in the TRRH (p = 0.023). The NRS pain scores were 3.05 ± 0.23 in the RARH group and 2.96 ± 0.26 in the TRRH (p = 0.019). The abdominal drainage extraction times were 7.54 ± 1.44 days in the RARH group and 7.00 ± 1.25 days in the TRRH (p = 0.016). Postoperative complications in the RARH group are fewer than TRRH (p = 0.033). TRRH is safe and feasible. Compared with RARHs, the TRRHs resulted in shorter incision lengths, operative times, intraoperative blood losses, postoperative hospital stays, first flatus times, first liquid diet times, and drainage tube removal times, and they improved NRS pain scores and postoperative complication frequencies.


Introduction
Colorectal cancer, a common digestive system malignancy, has shown annual morbidity and mortality rate increments with the life expectancy extension and dietary habit changes experienced by Chinese people [1,2]. Laparoscopic surgery is the most common surgical treatment for resectable colorectal cancer. However, the success of the procedure depends on imaging tools' features (most commonly in 2D) such as assistant cameras, ergonomic design, and the mobility of laparoscopic instruments. Operating on the free abdominal organs through the narrow pelvic space is difficult [3]. Robotic surgery was developed to overcome the shortcomings of laparoscopic surgery. The camera controlled by the surgeon provides stable amplification of 3-D images, high degree of angle and range of motion freedom, good ergonomics, and vibration filtering advantages to facilitate the anastomosis and reconstruction procedures [4,5]. A few studies have assessed the safety and feasibility of telerobotic-assisted right hemicolectomy, but the same variables remain unclear in TRRH due to lack of reports. Thus, in this study, we aimed to evaluate the safety and feasibility of TRRH to improve the quality of the evidence. Minimally invasive technologies have resulted in the development of intracorporeal anastomoses (IAs), which reduce the abdominal wall incision length needed for specimen removal and reduce the pressure changes under mesenteric traction. Therefore, IAs can reduce the risks of mesenteric torsion, wound infection, and incisional hernia. Studies have shown that IA after laparoscopic colectomy can reduce visceral injury and tissue stretching, contribute to faster intestinal function recovery, and shorten hospital stays [6]. However, laparoscopic IAs remain challenging. The Da Vinci system has gained recognition in the clinical practice due to the continuous improvement of surgical techniques. To the best of our knowledge, two studies have compared laparoscopic and robotic right hemicolectomies considering both anastomosis types (IA or extracorporeal anastomoses [EAs]) [7,8] and one study has compared laparoscopic EA with robotic IA [8]. Few studies have reported the safety and efficacy of the Da Vinci-assisted and the total Da Vinci lower right hemicolectomy procedures [9]. In their study, Gerbaud et al. [9] compared IA by TRRH with EA by RARH; they found intraoperative blood loss value differences between the two groups, but their study population involved only 42 cases (23 in the TRRH group and 19 in the RARH group) and the baseline levels were not balanced between them. Randomized controlled trials for RARH and TRRHs are lacking. Therefore, in our study, we used propensity score matching (PSM) to evaluate perioperative data and oncological outcomes after the two types of operations. Our purpose was to investigate the short-term outcomes of both RARHs and TRRHs.

Clinical materials
We defined the following inclusion criteria: ① patients between 18 and 80 years of age; ② presence of right colon cancer preoperatively confirmed by colonoscopic biopsy or computed tomography (CT); ③ conscious patients without cognitive impairment. We excluded patients with any of the following conditions from our study: ① acute intestinal obstruction, perforation, hemorrhage, or any other situation requiring emergency operations; ② multifocal colon cancer, distant metastasis or extensive abdominal metastasis; ③ metabolic disease, multiple organ failure, coagulation disorders, or other contraindications for surgical operations.
Based on the above-mentioned criteria, we designed a descriptive case series study to retrospectively review the clinical data of patients who had undergone TRRH from July 2016 to December 2021. We analyzed the data of 184 patients. Preoperative routine examinations such as chest X-rays, abdominal CTs, tumor marker examinations, and colonoscopies were performed to confirm the preoperative diagnosis and assess tumor staging. We adopted the surgical indications and contraindications recommended in the Expert Consensus of Robotic Surgery in Colorectal Cancer (2015 edition) [10]. The study was approved by the ethics committee. All patients signed a written informed consent. A single surgical team led by an experienced surgeon performed all the surgical operations, they followed a medialto-lateral approach for a complete mesocolic excision (CME) [11] followed by an antegrade anastomosis.
All patients were intubated and given general anesthesia in the supine position; the patient position was adjusted into a reverse Trendelenburg with an angle of 15-30° and a 20-25° left tilt. Figure 1 shows the port placement positions.
Pneumoperitoneum was established at 8-15 mmHg (1 mmHg = 0.133 kPa). The robotic arm system sat on the right shoulder, its center line crossing the laparoscopic hole to form a 45° angle from a transversal line crossing the right shoulder. A proper gap between the operation table and the patient's buttocks is needed to prevent the robotic arm from colliding with the right leg of the patient when dissociating the hepatic flexure. The surgeon performed the following procedures: 1) Operating area exposure: a medial-to-lateral approach was used, lifting the right mesentery revealed the intersection of the ileocolic artery and the superior mesenteric vein. 2) Vessels dissections: arteriovenous branches along the superior mesenteric vessels and lymph nodes were dissected. The ileocolonic artery and vein, the right colon artery and vein, the middle colon artery and vein or the right branch of the middle colon artery and vein were sequentially clipped and cut. The right gastro-omental artery and vein were severed on the pancreas during extended right hemicolectomies for ascending colon cancer and carcinoma of the transverse colon. 3) Ascending colon dissection: starting from right side of the superior mesenteric vein, along the avascular plane between Gerota's and Toldt's fasciae, the surgeon mobilized the colon in a medial-to-lateral direction to carry out its dissection (in a bottom up and inside-out manner) on the surface of the right spermatic cord or ovarian vessels, right ureter, pancreas and duodenum. During this step, the knee of the duodenum is a landmark to guide the dissection upwards, over the third duodenal portion and the pancreatic head along Fredet's fascia, whereas the right ureter and the gonadic vessels are left below the plane of dissection. 4) Hepatic flexure dissection: the right gastroepiploic vessels and related lymph nodes were dissected in patients with tumors in the ascending colon or hepatic flexure.
In addition, at least 10 cm of the omentum around from the tumor were dissected and resected. 5) Lateral peritoneum dissection. 6) Anastomosis: In the RARH group patients, an incision was made through the epigastrium, and the terminal ileum and transverse colon were pulled out outward to perform an end-to-side EA. In the TRRH group patients, an incision was made through the lower abdomen, the terminal ileum and transverse colon were cutoff with a robotic cutter and closure device, the terminal ileum and transverse colon were moved closer to the mesangial margin to perform a side-to-side IA. The other incisions were stapled with a cutter closure device.
A perioperative period therapy plan was set up and carried out by surgeons of the colorectal cancer team in our hospital, in accordance with the National Comprehensive Cancer Network (NCCN) guidelines. Postoperative routine parenteral nutrition and other symptomatic routine treatments were applied, and all patients received intravenous prophylactic antibiotics for less than 48 h. Surgeons removed drainage tubes after the operation as appropriate.

Outcome measures
We analyzed the following outcome measures: ① basic information; ② perioperative results including intraoperative, postoperative recovery, and postoperative complications indicators; ③ pathological results.

Statistical analysis
We expressed data as frequencies and percentages (%). The differences between groups were analyzed using Chi-square or Fisher's exact tests. We tested the normality of measurement data using the Shapiro-Wilk method. We calculated means ± standard deviations (mean ± SD) to describe normally distributed measurement data, and we applied t tests for comparisons between groups. We calculated medians and upper and lower quartiles (p 25 , p 75 ) for measurement data with skewed distributions, and we used the Mann-Whitney rank-sum test for comparisons between groups. We set the different surgical procedures as grouping variables and combined clinical characteristics and ASA scores as matching variables to obtain a 1:1 propensity score matching. The random number seed was set as 1234, the clamp value was 0.05, and the matching was done on the basis of the nearest neighbor matching method. We matched 148 patients (74 in TRRH group and 74 in the RARH group). All tests were two-sided, and we considered all differences with p-values < 0.05 as statistically significant. We used R (Version 4.1.0) as the propensity score matching software and SPSS 23.0 for the statistical analysis.

Basic information
After approval by the ethics committee of our institution, we collected the clinical data of 184 patients who had received right hemicolectomy in the Second Xiangya Hospital of Central South University from July 2016 to December 2021 for propensity score matching. After matching, we used the data of 148 patients (74 with TRAH and 74 with TRRH) for analysis. The RARH group consisted of 42 men and 32 women, and the TRRH group of 37 men and 37 women (p = 0.410). The mean age of the individuals in the RARH group was 58.84 ± 11.78 years and that of those in the TRRH group was 57.88 ± 14.21 years (p = 0.656). The mean body mass indexes BMIs were 22.42 kg/m 2 (20.92-24.54) for the RARH group and 21.44 kg/m 2 (20.21-24.17) for the TRRH group (p = 0.140). We found 12 (16.2%) patients with comorbidities and 62 (83.8%) without them in the RARH group, and 11 (14.9%) patients with comorbidities and 63 (85.1%) patients without them in the TRRH group (p = 0.821). In the RARH group, 14 patients (18.9%) had a history of abdominal surgery and 60 (81.1%) did not; and, in the TRRH group, 16 patients (21.6%) had a history of abdominal surgery and 58 (78.4%) did not (p = 0.683). We found 10 patients (13.5%) with combined surgical operations and 64 (86.5%) without them in the RARH group; and, we found 10 patients (13.5%) with combined surgical operations and 64 (86.5%) without them in the TRRH group (p = 1.000). The patients' ASA grades in the RARH group included p2 (33 patients, 44.6%), p3 (39 patients, 52.7%), and p4 (2 patients, 2.7%). The ASA grades in the TRRH group included p2 (33 patients, 44.6%), p3 (39 patients, 52.7%), and p4 (2 patients, 2.7%) (p = 1.000; Table 1).

Perioperative results
No emergency laparotomies were required in either group. The incision lengths were 5.14 ± 0.60 cm in the RARH group and 4.74 ± 0.55 cm in the TRRH group (p < 0.001). The blood losses were 86.28 ± 52.57 mL in the RARH group and 69.19 ± 44.78 mL in the TRRH group (p = 0.035). The operation time of the RARH group was 197.50 min (171. 25-242.25), and that of the TRRH group was 160.00 min (145.00-188.75) (p < 0.001; Table 2).
The postoperative hospital stays were 11.18 ± 4.32 days in the RARH group and 9.53 ± 4.42 days in the TRRH group (p = 0.023). The first flatus times were 3.70 ± 1.31 days in the RARH group and 3.34 ± 1.07 days in the TRRH group (p = 0.064). The first fluid diet times were 4.76 ± 1.19 days in the RARH group and 4.35 ± 1.07 days in the TRRH group (p = 0.046). NRS pain scores were 3.05 ± 0.23 in the RARH group and 2.96 ± 0.26 in the TRRH group (p = 0.019). The gastric tube extraction times were 1.62 ± 0.54 days in the RARH group and 1.70 ± 0.49 days in the TRRH group (p = 0.223). The abdominal drainage tube removal times were 7.54 ± 1.44 days in the RARH group and 7.00 ± 1.25 days in the TRRH group (p = 0.016) ( Table 3).

Discussion
Colorectal cancer is one of the most commonly identified tumors in China, and its incidence rate has been on the rise [1]. In China, the annual incidence of colorectal cancer (ranking third) is approximately 370,000. The annual death toll is around 180,000, making it the fifth deadliest condition [12]. Colorectal cancer guidelines still emphasize a comprehensive treatment on the basis of an early diagnosis and operation. While open and laparoscopic surgeries are first-line therapies and major surgical options for resectable colorectal cancer, open surgery is associated with severe trauma and bleeding. Similarly, laparoscopic surgery offers limited motion and dexterity features and presents evident technical difficulties when used during right colectomies due to the lack of fixed anatomical markers and the diversity of vascular pedicles [13]. The evidence suggests that robotic surgical systems are superior to others during pelvic operations, especially during colorectal, urological and gynecological operations [14]. Robotic right hemicolectomies have gathered attention following the successful introduction of robotic surgical systems into the general abdominal surgery field. The robotic technique averts the limitations of conventional laparoscopic procedures. In addition, it provides the following advantages as a new surgical option for right hemicolectomies [15][16][17]: (1) direct three-dimensional view, (2) hand-eye coordination, (3) hand tremor filtration, (4) high liberty degree of instruments, (5) visual amplification of tissues, organs and endowrist movements, and (6) a comfortable sitting position for the surgeon. Robotic right hemicolectomy is in its initial clinical application stages, and studies on TRAH are ongoing. A meta-analysis on data from 8 studies including 616 patients indicated that TRRH offers advantages over conventional laparoscopic surgery resulting in less intraoperative blood loss and time to first flatus [8]. In addition, a study on 70 operations revealed that RARH was safe and viable, but the operation time was longer and the cost was higher than with typical laparoscopic surgery, without a clear benefit [15]. Robotic technology advancements have rendered totally robotic surgery a new option for right colon cancer treatment, several foreign studies have compared TRRH with laparoscopic right hemicolectomy, and the results show the non-inferiority of TRRH [18][19][20][21].
Some researchers believe that TRRH is superior to laparoscopic surgery with shortened time to first flatus [18,22], and reduced intraoperative blood loss [22,23] and length of hospital stay [16]. Other researchers believe TRRH outcomes are similar to those of laparoscopic surgery [19]. Overall, most of those studies have shown that TRRH results in significantly shorter incision lengths and higher hospitalization costs than the corresponding laparoscopic operation [18][19][20][21]. Minimally invasive techniques have led to the development of IA. IA after colon resection can reduce visceral injury and tissue stretching, helping patients to recover the intestinal function more rapidly, and thus shortening their hospital stay [24]. However, IA has a long learning curve, and it presents risks of abdominal fecal overflow and other disadvantages [25]. The three-dimensional view of the robot and the large operating space in the abdominal cavity  [26,27]. At our center, on the basis of the evidence, we apply either of these two robotic surgical methods in our clinical practice. Specifically, we carry out counterclockwise sharp dissections under the right mesentery in an insideout manner using the Da Vinci robot using methods of totally robotic medial-to-lateral approach and complete mesocolic excision (CME) [15]; thus, allowing the surgeon to operate under direct vision to greatly reduce the risk of unplanned peripheral tissue damage that is high under indirect-vision operations. In this study, right hemicolectomies were successfully completed in both groups under robotic operation without the need for laparotomies. We had no accidental superior mesenteric vessel or abdominal organ injuries in either group. Moreover, operating under direct vision can shorten operating times, thereby reducing a prolonged anesthesia risks. In our study, the operation time of the RARH group was 197.50 min (171. 25-242.25), significantly longer than that of the TRRH group, which was 160.00 min (145.00, 188.75; p < 0.001). The operation durations of both procedures were significantly shorter than those reported by Trastulli et al. [18] and Yozgatli et al. [28] under TRRH (287.4 ± 76.4 min and 286 ± 77 min, respectively). This may be due to measurement inconsistencies in the studies. To reduce the influence of mechanical arm installation and other preoperative preparations on the operation duration, we ensured the time measured was exclusively the operating time. This reduced to some extent the influence of the length required for robotic arm installation and its learning curve. Interestingly, studies have shown total laparoscopic approaches being longer than laparoscopically assisted approaches, a finding differing from ours in our robotic analysis [16]. Totally robotic approaches probably benefit from the improved maneuverability of robots during vascular anastomoses. Surgical procedures under direct vision help control the bleeding of ileocolonic vessels (especially of the superior mesenteric veins). In our study, the amount of blood loss in the RARH group was 86.28 ± 52.57 mL, which was higher than that in the TRRH group at 69.19 ± 44.78 mL (p = 0.035). This result is consistent with that of Gerbaud et al. [9]. However, other studies found no significant differences in intraoperative blood losses between laparoscopic right hemicolectomy and total laparoscopic right hemicolectomy [7]. This may be related to the fact that ours was a retrospective study, and the statistics of blood loss were calculated from surgical records. The mean blood loss amounts in both our groups were less than those in Henry J. Lujan et al.'s study of conventional laparoscopic right hemicolectomy [29]. To some extent, this shows the advantages of the robot operating under counterclockwise free vision. Due to the inflexibility of the current laparoscopic operation, the specimen needs to fit a small abdominal incision. Most surgeons choose EA during laparoscopic right colon resections (laparoscopic-assisted rightside colon resection) [30]. The high degree of freedom of the robotic arm allows for both IAs and EAs. Some studies have shown that IAs have advantages over EA. Spinoglio G noted that the "potential advantages of intracorporeal anastomoses include the possibility of making smaller abdominal incisions at more convenient sites (such as McBurney or Pfannenstiel incisions) to extract specimens." [31] IAs provide better cosmetic results [32], reduce the incidence of incision hernias, and reduce postoperative pain [33]. In our study, the incision length of the RARH group was 5.14 ± 0.60 cm, longer than that of the TRRH group (4.74 ± 0.55 cm) with a statistically significant difference (p < 0.001). This further demonstrates the advantages of IAs. We found no instances of incisional hernia among our study population, although this may be because we only followed up patients for 30 days after surgery. The NRS pain score of the RARH group was higher than that of the TRRH group three days after surgery (p = 0.019), confirming the idea that IAs may reduce postoperative pain. Thus, in our hands, TRRHs had advantages over the RARHs in terms of incision length, esthetic degree, and postoperative pain.
Studies have shown that the application of IA during laparoscopic right hemicolectomies can reduce the incidence of short-term complications and the hospital stay lengths [18,25,32,34,35]. Considering the influence of clinical decision-making and preoperative preparation on the hospital stay length, we compared the hospital stay lengths by calculating the postoperative hospital stay lengths: the postoperative hospital stay in the RARH group (11.18 ± 4.32 days) was significantly longer than that in the TRRH group (9.53 ± 4.42 days; p = 0.023), which suggests that IAs can also reduce the postoperative hospital stay during robotic surgeries. The first flatus time (3.34 ± 1.07 days; p = 0.046) and the first fluid flow time (4.35 ± 1.07 days; p = 0.031) in the TRRH group were both shorter than those in the RARH group, indicating that TRRH was less traumatic and promoted a faster gastrointestinal function recovery than RARH. This may be due to the reduced visceral injury and tissue stretching achieved with endovascular anastomoses. Moreover, the abdominal drainage tube removal time in the RARH group (7.54 ± 1.44 days) was longer than that in the TRRH group (7.00 ± 1.25 days; p = 0.016); which also supports this view to some extent because the abdominal drainage tube removal time is affected by the degree of injury to the capillaries and lymphatic capillaries, and by the postoperative coagulation function.
According to the experience at our center, the full robot underside-to-side anastomosis can result in a wider anastomosis, longer mesangial margin and more intestinal wall tissue sutured, features that reduce the risk of anastomotic stenoses and anastomotic fistulas. The incidence of postoperative complications was lower in the TRRH than in the RARH group (p = 0.033). The total number of complications in this study was 15 (4%), a number consistent with those of other reports [36]. However, our small study population did not allow for analyses comparing specific complications. We found 5 patients (3.4%) with anastomosis-related complications (all anastomotic fistulas), a percentage similar to that in the report by Henry J. Lujan et al. [37]. Accordingly, robotic right hemicolectomy does not result in a higher incidence of postoperative anastomosis-related complications than that seen during the commonly used laparoscopic assistance. Bergamaschi et al. [38] showed that laparoscopic-assisted right hemicolectomy may increase the frequency of anastomotic stenoses caused by the number of sutures on the posterior intestinal wall, which is higher than the same number in fully laparoscopic right hemicolectomy. However, we found no patients with anastomotic stenosis. This may be because the robot provides improved flexibility and a clearer field of vision than the laparoscope. This further explains the shorter postoperative hospital stay in the TRRH group in our study. In addition, Trastulli S et al. reported a 3.9% incidence of intestinal obstruction after TRRH [18]. In our study, we found only 1 (0.7%) intestinal obstruction case in the RARH group. This may be due to the short follow-up time of our survey, and to our failure to include postoperative adhesion ileus in our study. Of note, in the TRRH group, 7 patients with chylous fistula (9.3%) underwent fasting and then initiated a low-oil diet, they had extended extubation times after surgery, which may be caused by the fact that the IA was carried out later than the EA In clinical application and the IA surgeon was closer to the vascular root when dissecting lymph nodes. IA provides a faster postoperative recovery and fewer complications than EA, but further large-scale studies should conduct multi-factor analyses of postoperative complications to determine other influencing factors.
In the published literature, the operative time of most robotic right colon surgeries is significantly longer than that of laparoscopic surgeries, a fact that increases anesthesia and other costs. [39,40] Robotic surgeries cost approximately $ 2000-5000 [41][42][43]. To the best of our knowledge, no studies have estimated the costs of robotic right hemicolectomy with either IA or EA. In this study, the total hospitalization cost of the RARH group was 122,300.06 yuan (111,839.74-133,756.46) and the total hospitalization cost of the TRRH group was 118,415.97 yuan (111,051.20-124,054.70), but the difference between the groups was not significant (p = 0.187). The cost of either of our groups was higher than the cost of the laparoscopic group in the above study. The initial costs of robotic surgical operations are likely to increase further due to management and promotion activities, but wide implementation and technological advancements will reduce the costs in the future. With improved surgeons' expertise in robotics and decreased fixed costs, robotic surgery may become the most cost-effective approach [44]. However, further investigation and cost analyses are needed to confirm this prediction.
One of the most important prognostic factors in right colon cancer is the number of lymph nodes harvested with the surgical specimen [45][46][47][48]. Through advantages like high-definition view, tremor filtration, and amplification, totally robotic procedures can prevent the rupture of lymph nodes, or gain an edge in the number of lymph nodes harvested. The American Joint Committee on Cancer (AJCC) consensus has recommended that right hemicolectomies extract at least 12 lymph nodes to achieve a radical cure. Studies have shown that robots can reduce lymph node damage during dissections, and they can completely remove lymph nodes (even fused ones) [49,50]. Tumors in the hepatic flexure of the transverse colon are difficult to remove with laparoscopic and open right hemicolectomies [18]. In this study, 18.51 ± 5.10 lymph nodes were dissected in the robot-assisted group. The number of lymph nodes dissected in the TRRH group was 19.24 ± 7.53 (p = 0.491), a number close to those reported in other studies [51]. All the operations on the 44 patients with tumors in the transverse colon and liver region reached the standard of 12 extracted lymph nodes (the precondition for a successful completion of surgery). The ratio of the number of lymph nodes extracted to the length of the surgical specimen (LN/LSS) is also an important prognostic indicator [52]. In our study, we found no significant differences in the LN/LSS ratio between the RARH and the TRRH groups, suggesting similar tumor eradication performances for both groups. However, TRRH may improve the postoperative recovery of patients with difficult-to-reach tumor locations and/or large lymph nodes.
Ours was a retrospective study with selection and recall biases. We matched patients on both groups according to their age, sex, BMI, presence of complications, history of abdominal or combined surgery, anesthesia ASA grade, and mass location to reduce these biases and make our results more reliable. According to studies, the number of operations required to complete the learning curve of a robotic right hemicolectomy is approximately 16 [53,54], and this learning curve may also affect the research results. The experience of our team of surgeons far exceeds the 16 operations.
Based on our results, the robot training and surgical cooperation of our team can be improved further. Long-term and randomized controlled studies are needed to determine the value and indications of these two surgical methods. In addition, a multicenter study with a large population should confirm detailed analyses and comparisons of the postoperative complications after these surgical methods. Cost-benefit analyses will be helpful for clinicians deciding which method to use.
This study provides one of the largest clinical outcome comparisons between RARH and TRRH. We believe our findings demonstrate the safety and efficacy of the robotic approach in the treatment of non-metastatic adenocarcinomas of the right colon. This will provide a certain basis for clinicians to choose surgical strategies in the future, and also provide a new research direction for other researchers.

Conclusion
We reached two main conclusions with our study: (1) TRRH in the hands of an experienced colorectal surgeon is safe and feasible. (2) Compared with RARH, the TRRH procedure seems to require a shorter incision length, operative time, postoperative hospital stay, first flatus time, first liquid diet time, and drainage tube removal time; in addition, TRRH results in a lower NRS pain score and less intraoperative blood loss and postoperative complications.