Objective: To investigate the technical feasibility of laparoscopic complete mesocolic excision (CME) for the radical treatment of right hemicolectomy. Methods We retrospectively analyzed the clinicopathological data and video data of 35 cases of laparoscopic CME performed at Ruijin Hospital of Shanghai Jiaotong University School of Medicine from March 2010 to September 2011, and analyzed their safety and technical feasibility; we used the West grading system to evaluate the surgical quality; we described the surgical access, anatomical levels and technical points of laparoscopic CME by anatomical drawing. Results (1) The visceral layer of fascia was wrapped around the entire colonic mesentery in an “envelope-like” manner, requiring sharp separation of the visceral wall layer of fascia by ultrasonic knife to achieve root ligation of blood vessels and complete mesenteric resection. (2) The intermediate approach takes the anatomical projection of the ileocolic vessels as the starting point, dissects the vessels along the main line of the superior mesenteric vein, and enters the natural surgical plane between the Told and the anterior renal fascia. (3) For cancers of the cecum and ascending colon, lymph nodes in the root of the ileum, right colon and middle colonic vessels should be cleared; for cancers of the hepatic flexure of the colon, group 6 lymph nodes should be cleared and the gastric omentum on the side of the greater curvature of the stomach 10-15 cm away from the tumor should be removed. (4) All 35 cases successfully completed laparoscopic CME; the quality of surgery was judged as grade C in 33 cases; the median number of lymph nodes cleared was 19 (15-25), and 25% of stage III patients had positive lymph nodes in the root of the mesentery; the median operation time was 2.6 (2-4) h, intraoperative bleeding was 80 (50-300) mL, postoperative time to exhaustion was 2 (1-4) d, and hospitalization time was 12 (6-20) d; 1 case of pulmonary infection, 1 case of bleeding, and 1 case of celiac leakage occurred after surgery. Conclusion CME is a new concept based on embryological anatomy and oncologic surgery and is expected to become a standardized surgical approach; intermediate access laparoscopic CME is technically feasible, and whether it improves the long-term outcome is to be confirmed by controlled studies.
Currently, total mesorectal excision (TME) has become the standardized surgical approach for lower and middle rectal cancer, and it has been recognized that it can reduce the local recurrence rate and make the long-term outcome of rectal cancer close to that of colon cancer [1-2]. In 2009, Hohenberger et al [3] proposed the first surgical procedure similar to TME: complete mesocolic excision (CME), which was found to reduce the local recurrence rate and improve the prognosis of colorectal cancer. It is expected to become the standard procedure for the radical treatment of colon cancer. The American COST confirmed that laparoscopic colon cancer surgery can achieve the same curative and 5-year survival rate as traditional open surgery [4], making laparoscopic surgery a better choice for the radical treatment of colon cancer. CME with conventional open surgery has been proven to be feasible and safe [5-9]. No study has reported whether laparoscopic CME can achieve the same results as open surgery from the technical aspect. The aim of this study was to investigate the technical points and difficulties of laparoscopic CME for the radical treatment of right hemicolectomy colon cancer. It is reported as follows.
1. Materials and methods
1.1 General data There were 35 cases of laparoscopic CME performed at the Clinical Medical Center of Minimally Invasive Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, from March 2010 to September 2011, including 18 male and 17 female cases, aged 35-84 years old, with an average of 65 years old. The surgical situation and postoperative recovery were analyzed. The UICC 6th edition staging system was used for tumor staging. A comparative anatomical approach was used to study the video and image data of laparoscopic CME and to explore the surgical access, surgical planes and technical points of laparoscopic CME.
Inclusion criteria: (1) clear pathological examination of cecum, ascending colon and colonic hepatic flexure cancer; (2) preoperative staging without distant metastasis; (3) tumor length diameter <6 cm; (4) elective surgery cases. Exclusion criteria: (1) non-cancerous cases such as malignant lymphoma of the right hemicolectomy; (2) distant metastasis found in preoperative staging; (3) huge tumor, extensive infiltration with surrounding tissues and organs (or) and tumor fusion encircling important blood vessels; (4) emergency surgery cases.
1.2 Surgical methods
1.2.1 Key points of CME technique Similar to TME, the dirty layer of fascia is “envelope-like” around the whole colonic mesentery.
1.2.2 Laparoscopic CME approach An intermediate surgical approach is used, with the anatomical projection of the ileocolic vessels (ICA and ICV) as the starting point, and the vessels are dissected along the main line of the superior mesenteric vein (SMV) (see Figure 1A, 1B, 2A, 2B).
1.2.3 Surgical plane finding and maintenance: enter the natural surgical plane between the Told fascia and the anterior renal fascia, expose the head of the pancreas, fully free the duodenum, laterally to the lateral peritoneal reflex of the colon, and superiorly to the root of the transverse colonic mesentery (see Figure 3A, 3B). The root of the corresponding colonic blood supply vessels was dissected, and the entire colonic mesentery was severed and removed completely (see Figure 3A and 3B).
1.2.4 Key points of lymph node dissection For cecum and ascending colon cancer, the lymph nodes at the roots of the ileocolon, right colon and middle colonic vessels should be thoroughly dissected, while for transverse colon hepatic flexure cancer, the right artery of the gastrointestinal omentum should be dissected at the roots to dissect the group 6 lymph nodes and the gastric omentum along the vascular arch of the gastrointestinal omentum 10-15 cm away from the tumor (see Figure 4A, 4B); if necessary, the Kocher If necessary, Kocher approach was adopted to free the duodenum, pancreatic head and mesenteric root, sharply separate the colonic mesentery up to the superior mesenteric artery (SMA), and thoroughly expose the colonic supply vessels to clear the lymph nodes.
1.3 Observation indexes (1) Surgical quality assessment: the grading system of West et al [10] was used to evaluate the surgical quality. grade A intrinsic muscle level: only a small amount of colonic mesentery was resected, and the axial nearest cut edge reached the intrinsic muscle layer of the intestinal wall; grade B intra-systemic level: irregular resection of part of the colonic mesentery, and the axial nearest cut edge exceeded the intrinsic muscle layer of the intestinal wall; grade C colonic mesentery level: complete resection of the colonic mesentery, with the mesenteric dirty layer (2) Surgery and postoperative recovery indexes: surgery time, intraoperative bleeding, lymph node dissection range, number of lymph node dissection, length of specimen; postoperative recovery: time of exhaustion, time of eating fluids after surgery, days of postoperative hospitalization, postoperative complications.
1.4 Statistical methods The SPSS for Windows 15.0 software package was applied for statistical analysis. The measurement data were expressed as median (full distance). Count data were expressed as rates.
2 , Results
2.1 Clinicopathological findings There were 7 cases of cecum cancer, 10 cases of ascending colon cancer, and 18 cases of colonic hepatic flexure cancer. There were 7 cases of low differentiated adenocarcinoma, 20 cases of middle differentiated adenocarcinoma, 4 cases of high differentiated adenocarcinoma, 3 cases of adenocarcinoma combined with mucinous adenocarcinoma, and 1 case of indolent cell carcinoma. Postoperative UICC pathological stage: 15 cases in stage II; 20 cases in stage III.
2.2 Surgical quality grading According to the surgical quality grading system, 33 cases were graded as grade C, with complete resection of the colonic mesentery and high ligation of the feeding vessels, and the specimens were shown in Figure 5.
2.3 Lymph node dissection The length of the surgically resected specimen was (18.32 ± 8.26) cm. 19 (15-25) lymph nodes were dissected, and 5 (25%) stage III patients had positive lymph nodes in the root of the mesentery; 3 (17%) of the 18 cases had positive lymph node dissection in group 6 of the hepatic flexure of the colon, and 1 (5.5%) had positive lymph nodes in the gastric omentum on the side of the greater curvature of the stomach.
2.4 Surgical-related conditions There were no surgical deaths and no cases of transit in the whole group. The operation time was 2.5 (2~4) h, and the intraoperative bleeding was 80 (50~300) mL. 10 cases were treated with postoperative analgesic drugs (dulcolax).
2.5 Postoperative recovery Postoperative bowel evacuation time was 2 (1~4) d, resumption of liquid diet was 3 (3~5) d, postoperative bed activity was 3 (2~7) d, and hospital stay was 12 (6~20) d.
2.6 Surgical complications Three cases (8.6%) of complications occurred, one case of postoperative pulmonary infection, one case of bleeding, and one case of celiac leakage, all of which improved after symptomatic treatment. There were no fatal cases.
3. Discussion
3.1 Theoretical basis and efficacy of CME The total mesorectal excision (TME) reported by Heald [11] in 1982 and the circumferential resection margin (CRM) reported by Quirke et al [12] in 1986 are two contemporary It has become a standardized surgical approach for rectal cancer surgery, significantly reducing the local recurrence rate of rectal cancer and improving the prognosis. However, colon cancer surgery still lacks standardized criteria. tme emphasizes sharp separation of the visceral layer from the mural fascia and ensures the integrity of the visceral fascia to ensure complete removal of regional lymph nodes. Embryological anatomical studies suggest that the visceral and mural fascia also extend to the entire colon, covering the sigmoid colon, descending colon, to the posterior of the pancreas, including the duodenum, the head of the pancreas and the entire right hemicolectomy, covering the colonic mesentery in an “envelope-like” fashion [3]. Based on the “envelope” theory, Hohenburger et al. proposed complete mesenteric resection (CME) as the concept of standardized surgery for colon cancer in 2009. The group studied 1438 colon cancer patients and found that CME resected specimens were more compatible with oncological characteristics and that CME reduced the 5-year local recurrence rate and increased the 5-year tumor-related survival rate [3]. Therefore, CME and TME are one and the same and complement each other, and CME is an extension and development of TME.
3.2 Key points and difficulties of laparoscopic CME
3.2.1 Surgical access selection There are two surgical accesses to achieve CME, namely, the peripheral access (lateral access) and the medial access. In traditional open surgery, the peripheral access is mostly used to free the right hemicocele and sharply separate the visceral fascia covering the pancreas and mesentery from the mural peritoneum covering the retroperitoneal tissue up to the superior mesenteric artery to expose the colonic supply vessels. In contrast, the surgical approach of laparoscopic CME has not been reported in the literature. In our group, CME was successfully achieved using the intermediate surgical approach, which starts with the anatomical projection of the ileocolic vessels [13], dissects the vessels along the main line of the superior mesenteric vein, then enters the natural surgical plane until the lateral peritoneum of the colon is reflexed, followed by a central root dissection of the colonic vessels to achieve complete resection of the entire colonic mesentery. The difference between the two surgical approaches is that the former is to free the colon first and then separate the root of the ligated vessels, which is relatively easy to operate, while the latter is to separate the ligated vessels first and then the intestinal segment, which is more in line with the principle of radical tumor treatment. In our opinion, the intermediate approach is more consistent with the principle of “tumor free” and facilitates laparoscopic CME of the right hemicolectomy.
In 2005, Guillou et al [14] proposed to grade the quality of surgery according to the pathological manifestations of resected colon specimens: intrinsic muscle level (poor), intracolonic level (good), and colonic mesenteric level (excellent). prognosis of different quality surgeries and found that the overall survival of patients who underwent surgery at the colonic mesenteric level was significantly longer than other surgical quality groups. Thus CME is a surgical approach of the highest quality, with more emphasis on finding and maintaining the anatomical level and complete lymphatic clearance. Of the 35 cases in our group, 33 were of surgical quality grade C and 2 were of grade B, suggesting that CME can be achieved at the technical level laparoscopically. what are the technical points and difficulties? We believe that (1) ultrasonic knife can be used to open the superior mesenteric vein vascular sheath, which facilitates the correct search of the avascular plane between Told’s fascia and anterior renal fascia, effectively avoiding the level too shallow to enter the colonic mesentery leading to bleeding and mesenteric defect, and the level too deep to damage the retroperitoneal ureter and other important organs; it facilitates the search of the colonic blood supply vessels from the root, thus realizing accurate root ligation and clearing the central group lymph nodes. (2) The working surface of the ultrasonic cutter head needs to be kept away from the vessels during vascular dissection, and the non-working surface is used against the vessels, which can effectively avoid the injury of important vessels such as the superior mesenteric vessels that can lead to hemorrhage. (3) The first assistant needs to fan out the colonic mesentery during surgery to maintain certain tension and adjust the traction position as needed, which can effectively overcome the shortage of laparoscopic surgery against traction as compared with open surgery. (4) A relatively fixed surgical group and systematic technical training can shorten the learning curve of laparoscopic CME.
3.3 CME and D3 radical surgery Is CME a new surgical approach or a new concept? However, the introduction of the TME concept provided a theoretical basis in oncologic surgery and embryological anatomy for radical rectal cancer, which led to unprecedented standardization of the procedure and its application worldwide. Compared with traditional D3 radical surgery for right hemicolectomy, CME emphasizes: (1) maximum clearance of lymph nodes along the root dissection of tumor drainage vessels; (2) finding and maintaining the embryological anatomical surgical plane to ensure smooth and intact visceral fascia without defects. (3) Based on the course of the colonic blood supply vessels, the scope of resection is greater. It should be said that CME is an innovation and sublimation of traditional radical surgery in theory and practice. And does CME increase the complications of surgery? The complications in this group were 8.6%, and all of them improved after non-surgical treatment, and there were no fatal cases, which is consistent with the results of Hohenburger’s study, suggesting that CME is safe. However, more high-level evidence-based evidence is needed to support whether CME surgery improves the 5-year survival rate and prognosis of colon cancer compared with conventional D3 radical surgery.
To date, there have been no revolutionary theoretical and practical advances in colon cancer surgery. CME presents a new concept for radical right hemicolectomy based on embryological anatomy and oncologic surgery, and is expected to become a standardized surgical approach and repeat the history of TME. Intermediate access laparoscopic CME is technically feasible, and whether it improves long-term outcome is to be confirmed by RCT studies.