The successful report of total mesorectal excision (TME)/complete mesocolic excision (CME) has encouraged people to apply this concept beyond colorectal surgery. However, the negative results of the JCOG1001 trial denied the effect of complete resection of the "mesogastrium" including the greater omentum on the oncological survival of gastric cancer patients. People even believe that the mesentery is unique in the intestine, because they have a vague understanding of the structure of the mesentery. The discovery of proximal segment of the dorsal mesogastrium (PSDM) proved that the greater omentum is not the mesogastrium, and further revised the structure (definition) of the mesentery and revealed its container characteristics, i.e. the mesentery is an envelope-like structure, which is formed by the primary fascia (and serosa) that enclose the tissue/organ/system and its feeding structures, leading to and suspended on the posterior wall of the body. Breakdown of this structure leads to the simultaneous reduction of surgical and oncological effects of surgery. People quickly realized the universality of this structure and causality which cannot be matched by the existing theories of organ anatomy and vascular anatomy, so a new theory and surgical map- membrane anatomy began to form, which led to radical surgery upgraded from histological en bloc resection to anatomic en bloc resection.
Humans ; Fascia/anatomy & histology* ; Laparoscopy ; Lymph Node Excision/methods* ; Mesentery/surgery* ; Mesocolon/surgery* ; Omentum ; Serous Membrane ; Clinical Trials as Topic

Complete mesocolic excision (CME) and D3 resection of right colon cancer have been widely implemented, but the definition and identification of the completeness of the mesentery have not been fully agreed, especially the dorsal and medial borders. In this paper, we proposed the dorsal fascia of the colonic mesentery as the dorsal border of the mesocolon and the line connecting the roots of the ileocolic artery and the middle colic artery (ICA-MCA line) as the medial border of the CME by systematically studying the relationship between the mesentery and the mesenteric bed from the theory of membrane anatomy, combined with surgical experience and in-depth review of ontogenetic anatomy. We also proposed the visible "superior mesenteric vein notch" and "middle colic artery triangle" on surgical specimens as identifiers of mesocolic completeness.
Humans ; Mesocolon/surgery* ; Lymph Node Excision ; Colectomy ; Laparoscopy ; Colonic Neoplasms/surgery*

Objective: To investigate anatomical morphology and classification of persistent descending mesocolon (PDM) in patients with left-sided colorectal cancer, as well as the safety of laparoscopic radical surgery for these patients. Methods: This is a descriptive study of case series. Relevant clinical data of 995 patients with left colon and rectal cancer who had undergone radical surgery in Fujian Medical University Union Hospital from July 2021 to September 2022 were extracted from the colorectal surgery database of our institution and retrospectively analyzed. Twenty-four (2.4%) were identified as PDM and their imaging data and intra-operative videos were reviewed. We determined the distribution and morphology of the descending colon and mesocolon, and evaluated the feasibility and complications of laparoscopic surgery. We classified PDM according to its anatomical characteristics as follows: Type 0: PDM combined with malrotation of the midgut or persistent ascending mesocolon; Type 1: unfixed mesocolon at the junction between transverse and descending colon; Type 2: PDM with descending colon shifted medially (Type 2A) or to the right side (Type 2B) of the abdominal aorta at the level of the origin of the inferior mesentery artery (IMA); and Type 3: the mesocolon of the descending-sigmoid junction unfixed and the descending colon shifted medially and caudally to the origin of IMA. Results: The diagnosis of PDM was determined based on preoperative imaging findings in 9 of the 24 patients (37.5%) with left-sided colorectal cancer, while the remaining diagnoses were made during intraoperative assessment. Among 24 patients, 22 were male and 2 were female. The mean age was (63±9) years. We classified PDM as follows: Type 0 accounted for 4.2% (1/24); Type 1 for 8.3% (2/24); Types 2A and 2B for 37.5% (9/24) and 25.0% (6/24), respectively; and Type 3 accounted for 25.0% (6/24). All patients with PDM had adhesions of the mesocolon that required adhesiolysis. Additionally, 20 (83.3%) of them had adhesions between the mesentery of the ileum and colon. Twelve patients (50.0%) required mobilization of the splenic flexure. The inferior mesenteric artery branches had a common trunk in 14 patients (58.3%). Twenty-four patients underwent D3 surgery without conversion to laparotomy; the origin of the IMA being preserved in 22 (91.7%) of them. Proximal colon ischemia occurred intraoperatively in two patients (8.3%) who had undergone high ligation at the origin of the IMA. One of these patients had a juxta-anal low rectal cancer and underwent intersphincteric abdominoperineal resection because of poor preoperative anal function. Laparoscopic subtotal colectomy was considered necessary for the other patient. The duration of surgery was (260±100) minutes and the median estimated blood loss was 50 (20-200) mL. The median number of No. 253 lymph nodes harvested was 3 (0-20), and one patient (4.2%) had No.253 nodal metastases. The median postoperative hospital stay was 8 (4-23) days, and the incidence of complications 16.7% (4/24). There were no instances of postoperative colon ischemia or necrosis observed. One patient (4.2%) with stage IIA rectal cancer developed Grade B (Clavien-Dindo III) anastomotic leak and underwent elective ileostomy. The other complications were Grade I-II. Conclusions: PDM is frequently associated with mesenteric adhesions. Our proposed classification can assist surgeons in identifying the descending colon and mesocolon during adhesion lysis in laparoscopic surgery. It is crucial to protect the colorectal blood supply at the resection margin to minimize the need for unplanned extended colectomy, the Hartmann procedure, or permanent stomas.
Humans ; Male ; Female ; Middle Aged ; Aged ; Mesocolon/surgery* ; Retrospective Studies ; Laparoscopy/methods* ; Rectal Neoplasms/surgery* ; Colectomy/methods* ; Ischemia

The extent of D3 lymphadenectomy for right colon cancer, especially the medial border of central lymph node dissection remains controversial. D3 lymphadenectomy and complete mesocolon excision (CME) are two standard procedures for locally advanced right colon carcinoma. D3 lymphadenectomy determines the medial border according to the distribution of the lymph nodes. The mainstream medial border should be the left side of superior mesenteric vein (SMV) according to the definition of D3, but there are also some reports that regards the left side of superior mesenteric artery (SMA) as the medial border. In contrast, the CME procedure emphasizes the beginning of the colonic mesentery and the left side of SMA should be considered as the medial border. Combined with the anatomical basis, oncological efficacy and technical feasibility of D3 lymph node dissection, we think that it is safe and feasible to take the left side of SMA as the medial boundary of D3 lymph node dissection. This procedure not only takes into account the integrity of mesangial and regional lymph node dissection, but also dissects more distant lymph nodes at risk of metastasis. It has its anatomical basis and potential oncological advantages. However, at present, this technical concept is still in the exploratory stage in practice, and the related clinical evidence is not sufficient.
Colectomy/methods* ; Colonic Neoplasms/surgery* ; Humans ; Laparoscopy/methods* ; Lymph Node Excision/methods* ; Mesocolon/surgery*

Total mesorectal excision (TME) represents the gold standard for radical resection in rectal cancer. The development in radiology and laparoscopic surgical equipment and the advancement in technology have led to a deepened understanding of the mesorectum and its surrounding structures. Both the accuracy of preoperative staging and the preciseness of the planes of TME surgical dissection have been enhanced. The postoperative local recurrence rate is reduced and the long-term survival of rectal cancer patients is improved. The preservation of the pelvic autonomic nervous system maintains the patient's urinary and sexual functions to the greatest extent possible, which in turn improves the patient's postoperative quality of life. A thorough understanding of the anatomy of the mesorectum and its surrounding structures is a prerequisite for successful TME. Herein, we review the basic concepts and the anatomy of the mesorectum in the current literature. Some important clinical issues are also discussed systematically in terms of imaging, surgery, and pathology.
Humans ; Laparoscopy/methods* ; Mesocolon/surgery* ; Quality of Life ; Rectal Neoplasms/surgery* ; Rectum/surgery*

Objective: At present, surgeons do not know enough about the mesenteric morphology of the colonic splenic flexure, resulting in many problems in the complete mesenteric resection of cancer around the splenic flexure. In this study, the morphology of the mesentery during the mobilization of the colonic splenic flexure was continuously observed in vivo, and from the embryological point of view, the unique mesenteric morphology of the colonic splenic flexure was reconstructed in three dimensions to help surgeons further understand the mesangial structure of the region. Methods: A total of 9 patients with left colon cancer who underwent laparoscopic radical resection with splenic flexure mobilization by the same group of surgeons in Union Hospital of Fujian Medical University from January 2018 to June 2019 were enrolled. The splenic flexure was mobilized using a "three-way approach" strategy based on a middle-lateral approach. During the process of splenic flexure mobilization, the morphology of the transverse mesocolon and descending mesocolon were observed and reconstructed from the embryological point of view. The lower margin of the pancreas was set as the axis, and 4 pictures for each patient (section 1-section 4) were taken during middle-lateral mobilization. Results: The median operation time of the splenic flexure mobilization procedure was 31 (12-55) minutes, and the median bleeding volume was 5 (2-30) ml. One patient suffered from lower splenic vessel injury during the operation and the bleeding was stopped successfully after hemostasis with an ultrasound scalpel. The transverse mesocolon root was observed in all 9 (100%) patients, locating under pancreas, whose inner side was more obvious and tough, and the structure gradually disappeared in the tail of the pancreatic body, replaced by smooth inter-transitional mesocolon and dorsal lobes of the descending colon. The mesenteric morphology of the splenic flexure was reconstructed by intraoperative observation. The transverse mesocolon was continuous with a fan-shaped descending mesocolon. During the embryonic stage, the medial part (section 1-section 2) of the transverse mesocolon and the descending mesocolon were pulled and folded by the superior mesenteric artery (SMA). Then, the transverse mesocolon root was formed by compression of the pancreas on the folding area of the transverse mesocolon and the descending mesocolon. The lateral side of the transverse mesocolon root (section 3-section 4) was distant from the mechanical traction of the SMA, and the corresponding folding area was not compressed by the tail of the pancreas. The posterior mesangial lobe of the transverse mesocolon and the descending mesocolon were continuous with each other, forming a smooth lobe. This smooth lobe laid flat on the corresponding membrane bed composed of the tail of pancreas, Gerota's fascia and inferior pole of the spleen. Conclusions: From an embryological point of view, this study reconstructs the mesenteric morphology of the splenic flexure and proposes a transverse mesocolon root structure that can be observed consistently intraopertively. Cutting the transverse mesocolon root at the level of Gerota's fascia can ensure the complete resection of the mesentery of the transverse colon.
Colectomy/methods* ; Colon, Transverse/surgery* ; Colonic Neoplasms/surgery* ; Dissection ; Fascia/anatomy & histology* ; Humans ; Laparoscopy ; Mesentery/surgery* ; Mesocolon/surgery* ; Pancreas/surgery* ; Photography ; Spleen/surgery*

D3 lymphadenectomy and complete mesocolic excision (CME) for colon cancer, which have been introduced to China for more than 10 years, are two major surgical principles worldwide. However, there are still many different opinions and misunderstandings about the core principles of D3 and CME, especially the similarities and differences between them. However, few articles have been published to discuss these issues specifically. Domestic scholars' understandings about D3 lymphadenectomy and CME for right hemicolectomy are quite different. Two different concepts including "D3/CME" and "D3+CME" have become mainstream views. The former equate D3 with CME and the latter seems to regard them as totally different principles. There is no consensus on which one is more reasonable. Therefore, this article aims to discuss the similarities and differences between D3 and CME for right hemicolectomy in perspectives of the theoretical background, surgical principles, extent of surgery and oncological outcomes. We believed that D3 and CME do not belong to the same concept, and that the scope of CME surgery for right-sided colon cancer is greater than and includes the scope of D3 surgery, and that D3 and CME are not complementary.
Colectomy/methods* ; Colonic Neoplasms/surgery* ; Humans ; Laparoscopy ; Lymph Node Excision/methods* ; Mesocolon/surgery*

The incidence of anastomotic leak after right hemicolectomy for cancer is relatively low, but it may be misjudged. In recent years, the results of some multi-center or nationwide registration studies in Europe have shown that the incidence of anastomotic leak is significantly higher than that of eastern countries. The reasons of these differences may be the different nature of the studies, the lack of rigor in diagnostic criteria or diagnostic methods, the difference in the level of specialization of hospitals or surgeons, and so on. Timely treatment of preoperative comorbidities, reasonable selection of preoperative bowel preparation and anastomotic technique/method might reduce the occurrence of anastomotic leak. The current evidence shows complete mesocolic excision (CME) does not increase the risk of anastomotic leak. The clinical features of ileo-colic anastomotic leak are different from those of rectal surgery. The mild cases can be treated conservatively, and the severe cases are suggested to receive timely diverting ileostomy.
Anastomosis, Surgical/adverse effects* ; Anastomotic Leak/surgery* ; Colectomy ; Europe ; Humans ; Mesocolon/surgery* ; Neoplasms ; Retrospective Studies ; Risk Factors

The mesentery is a continuous unity and the operation of digestive carcinoma is the process of mesenteric resection. This paper attempts to simplify the formation process of all kinds of fusion fascia in the process of digestive tract embryogenesis, and to illuminate the continuity of fusion fascia with a holistic concept. This is helpful for beginners to reversely dissect the fusion fascia and maintain the correct surgical plane during operation, and to achieve the purpose of complete mesenteric resection.
Colonic Neoplasms/surgery* ; Gastrointestinal Neoplasms/surgery* ; Humans ; Laparoscopy ; Mesentery/surgery* ; Mesocolon

Like other solid tumors, colon cancer surgery has undergone a century-old journey from lumpectomy to organ resection and then to lymphadenectomy. From the Toldt fascia to complete mesenteric resection, and from local resection to D3 radical treatment, local recurrence rates have been reduced, but remain a nuisance to surgeons and patients. Based on the theory of membrane anatomy, radical surgery for colon cancer will focus more on removing the mesocolon from the mesentery bed while maintaining the integrity of the posterior fascia to avoid the occurrence of "fifth metastasis" as much as possible. Thanks to the membrane anatomy theory, its strong reproducibility and replicability, a new phase of colorectal surgery is on the horizon.
Colectomy ; Colonic Neoplasms/surgery* ; Humans ; Laparoscopy ; Lymph Node Excision ; Mesentery/surgery* ; Mesocolon/surgery* ; Neoplasm Recurrence, Local ; Reproducibility of Results