Total mesorectal excision (TME) has become the gold standard for mid-low rectal cancer surgery. However, for some patients with obesity and narrow pelvis, there are great challenges in both open and laparoscopic surgery. Transanal total mesorectal excision (taTME) uses a transanal approach, in " bottom-up" direction, which reduces the difficulty of distal mesorectal excision and may improve the quality of the TME specimen. The taTME provides a direct sight of the tumor and the distal resection margin is more precise. However, whether taTME can achieve complete total mesorectal excision, especially for mid-rectal cancer, is still controversial. This study compares the quality and integrity of mesorectum among open surgery, laparoscopic surgery, and taTME surgery according to TME principles and quality evaluation criteria of TME specimen. In conclusion, the integrity of mesorectum of taTME specimens for low-rectal cancer is good. But for the mid-rectal cancer, the integrity of mesorectum of taTME specimens and long-term efficacy are still controversial and need high-level evidence support.
Humans ; Laparoscopy ; Mesocolon ; Obesity ; Rectal Neoplasms ; Rectum ; surgery

The precise anatomic surgery is the cornerstone of curative resection and is becoming a trend of modern surgery. Currently, there are still many inadequate resections of colon cancer continue to be performed. Complete mesocolic excision (CME) according to the surgical plane, based on the principles of oncology, is a high-quality radical operation obtaining optimal oncological pathological specimen, with precise surgical concept throughout the entire surgical procedure. CME has been proposed for three years. Although there are still some controversies, CME has set off a worldwide climax of emphasis on quality of colon surgery. It is time to focus on the quality of colon-cancer surgery in order to ensure that all patients with colon cancer receive the highest possible chance for cure.
Colonic Neoplasms ; Consensus ; Digestive System Surgical Procedures ; Humans ; Mesocolon ; surgery

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

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*

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*

Objective: To investigate the anatomic characteristics of the left parietal peritoneum and its surgical implementation while dissecting in left retro-mesocolic space. Methods: A descriptive case series research methods was used. (1) surgical videos of 35 patients who underwent laparoscopic radical resection (complete mobilization of splenic flexure) of colorectal cancer in Union Hospital of Fujian Medical University between January 2018 and December 2018 were reviewed; (2) four specimens after radical resection of rectal cancer performing in June 2020 were prospectively enrolled and reviewed; (3) five specimens of left parietal peritoneum from 5 cadaveric abdomen (3 males and 2 females) were enrolled and reviewed as well; Tissues of 3 unseparated regions, namely the root of the inferior mesenteric artery (IMA), the medial region and the lateral region (including kidney tissue), from above the 5 cadaveric abdominal specimens were selected to perform Masson staining and histopathological examination. Results: (1) Surgical video observation: "Staggered layer phenomenon" and typical left parietal peritoneum was found in 77.1% (27/35) of patients when the left retro-mesocolic space was separated from the lateral and central approaches. The left parietal peritoneum presented as a rigid fascia barrier between the lateral and central approaches, which was a translucent dense connective tissue fascia. After the splenic flexure were completely mobilized, the left parietal peritoneum stump continued to the cephalic side. (2) Observation of 4 surgical specimens: The dorsal side of the left mesocolon specimen was studied, and the left parietal peritoneum stump edge was identified. The outside of the stump edge was the left hemicolon dorsal layer, which was continuously downward to the rectal fascia propria. (3) Cadaveric abdominal specimens: The left retro-mesocolic space was separated through lateral and central approaches, and the rigid fascia barrier, essentially the left parietal peritoneum and Gerota fascia, was encountered. Cross-section view showed that the left parietal peritoneum could be further detached from the dorsal layer of the left mesocolon from the outside, but could not be further detached from the inside out. (4) Histological examination: There was no obvious fascia structure in the IMA root region, while outside the IMA root region, the left bundle of inferior mesenteric plexus penetrating Gerota fascia was observed. There were 4 layers of fascias in the medial region, including the ventral layer of the left mesocolon, the dorsal layer of the left mesocolon, left parietal peritoneum and Gerota fascia. Small vessels were observed between the dorsal layer of the left mesocolon and the left parietal peritoneum. In lateral region, renal tissue and renal fascia were observed. Three layers of fascia structures were observed clearly under high power field, including the dorsal layer of the left mesocolon, left parietal peritoneum, and Gerota fascia. Conclusions: The left parietal peritoneum is the anatomical basis of the "staggered layer phenomenon" from the lateral or central approaches during the separation of left retro-mesocolic space. The small vessels in the dissection plane are the anatomical basis of intraoperative microbleeding, which need pre-coagulation. The central part of Gerota fascia is penetrated by the branches of the inferior mesenteric plexus, which results in a relatively dense surgical plane. Thus, during the dissection through the central approach, it is easy to involve in wrong surgical plane by deeper dissection.
Colon, Transverse ; Colonic Neoplasms/surgery* ; Dissection ; Female ; Humans ; Laparoscopy ; Male ; Mesocolon ; Peritoneum ; Rectal Neoplasms/surgery*

Objective: To investigate the anatomic characteristics of the right retroperitoneal fascia and its surgical implementation while performing complete mesocolic excision (CME) for right colon cancer. Methods: A descriptive study was carried out. (1) Clinicopathological data and surgical videos of 17 non-consecutive patients undergoing laparoscopic right hemicolectomy (extended right hemicolectomy) with CME for right colon cancer at Department of Colorectal Surgery of Union Hospital, Fujian Medical University between January 2020 and October 2020 were retrospectively collected. The construction of right retroperitoneal fascia was observed from caudal dorsal direction and caudal ventral direction. (2) Three postoperative specimens from 3 cases undergoing laparoscopic right hemicolectomy with CME for right colon cancer in June 2020 were prospectively included to observe anatomy and examine histology. (3) Five abdominal cadaver specimens from the Department of Anatomy of Fujian Medical University were enrolled, including 3 males and 2 females. Anatomical observation and histological studies were performed from the cranial approach and the caudal dorsal approach. Masson staining was used to examine the histology. Results: (1) Surgical video observation: The typical structure of right retroperitoneal fascia could be observed in all the 17 patients. The fascia was a rigid barrier between the posterior space of the ascending colon and the anterior pancreaticoduodenal space behind the transverse colon. The right retroperitoneal fascia should be sharply cut to communicate between the two spaces to avoid entering the right mesocolon by mistake. The severed ventral stump of the right retroperitoneal fascia ran along the dorsal side of the right hemicolon to the lateral side, and the dorsal stump covered the level of the duodenum caudally, and continued to move downward, covering the surface of Gerota's fascia. (2) Observation of 3 surgical specimens: The dorsal side of the right mesocolon was smooth and intact, which could be anchored in the corresponding area of the lateral edge of the duodenum. The ventral stump of the right retroperitoneal fascia could be seen, which attached to the dorsal side of the right mesocolon semi-circularly. Masson staining observation: The ventral stump of the right retroperitoneal fascia ran cephalad, fused with the dorsal side of the right mesocolon tightly and curled. The caudal side of confluence and the dorsal side of the right mesocolon presented a bilobed structure. (3) Anatomy of 5 cadaveric specimens: The right retroperitoneal fascia was a thin fascia structure, which was a rigid barrier between the anterior pancreaticoduodenal space behind the transverse colon and the posterior space of the ascending colon. The ventral stump of the right retroperitoneal fascia (including the dorsal side of the right mesocolon), the dorsal stump of the right retroperitoneal fascia (including part of the duodenal wall) and the dorsal side of the right mesocolon were retrieved for histological examination. The ventral stump of the right retroperitoneal fascia fused with the dorsal side of the right mesocolon by the cephalic side, and the dorsal side of the right hemi-mesocolon on the fusion level by caudal side gradually separated into a double-layer loose fascial structure. The dorsal stump of the right retroperitoneal fascia covered the surface of the duodenum level, moved on from the ventral side to the surface of the prerenal fascia, and continued to the caudal side. Conclusions: The right retroperitoneal fascia is a rigid barrier between the anterior pancreaticoduodenal space behind the transverse colon and the posterior space of the ascending colon. The Toldt fascia formed by fusion with the dorsal lobe of the right colon travels to the edge of the descending and horizontal part of the duodenum and separates again. The right retroperitoneal fascia is attached to the edge of the duodenum, reversing and running on the surface of the prerenal fascia, while the dorsal lobe of the right colon runs in front of the pancreas and duodenum, and shifts to the pancreaticoduodenal fascia. During the operation, this fascia should be identified and cut to penetrate the anterior pancreaticoduodenal space behind the transverse colon and the posterior ascending colon space, which helps to ensure the integrity of the dorsal side of the right hemi-mesocolon.
Abdominal Wall ; Colectomy ; Colonic Neoplasms/surgery* ; Fascia ; Female ; Humans ; Laparoscopy ; Male ; Mesocolon/surgery* ; Retrospective Studies

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*

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*

Laparoscopic radical colectomies have been more widely used gradually, among which laparoscopic extended right hemicolectomy is considered as the most difficult procedure. The difficulty of extended right hemicolectomy lies in the need to dissect lymph nodes along the superior mesenteric vein (SMV) and disconnect numerous and possible aberrant vessels. To address this problem, we emphasize two points in key vessel assessment: getting familiar with the anatomy along the medial-to-lateral approach and having a good understanding about the preoperative imaging presentations. An accurately preoperative imaging assessment by abdominal enhanced CT can help the surgeon understand the relative position of the key vessels to be dealt with during operation and the situation of the possible aberrant vessels so as to guide the procedure more effectively and facilitate the prevention and management of the intraoperative complications. During operation, the operator should pay special attention to the management of the vessels in the ileocolic vessel region, Henle's trunk and middle colon vessels. The operation highlights of the key vessels are as follows: (1) The ileocolic vessels: identifying the Toldt's gap correctly and opening the vascular sheath of the SMV securely; making sure that the duodenum is well protected. (2) Henle's trunk: dissecting along the surface of the Henle's trunk; preserving the anterior superior pancreaticoduodenal vein (ASPDV) and main trunk of the Henle's trunk; disconnecting the roots of the right colic vein (RCV) and right gastroepiploic vein (RGEV), and then dissecting lymph nodes along the surface of the pancreas. (3) The middle colon vessels: identifying the root of the middle colon vessel along the lower edge of the pancreas; avoiding entering behind the pancreas; mobilizing the transverse mesocolon sufficiently along the surface of the pancreas. Finally, we discuss and analyze the disputes currently existing in laparoscopic extended right hemicolectomy, including dissection of No.6 lymph nodes, naking the SMA and dissecting lymph nodes around the roots of the branches of SMA. This article shares our experience about laparoscopic extended right hemicolectomy, hoping that it could help beginners master the technique more safely and skillfully.
Colectomy ; methods ; Colon, Transverse ; Colonic Neoplasms ; surgery ; Humans ; Laparoscopy ; Mesocolon ; surgery