1.Recognition of the rectal mesentery
According to traditional anatomy, the mesentery is a structure containing nutrient supplying blood vessels, lymphatic vessels, innervated nerves and fat wrapped by two layers of peritoneum, and generally only the endo-peritoneal organs such as transverse colon and small intestine have this membrane, while the meso-peritoneal organs ascending colon, descending colon, upper rectum and extra-peritoneal organs – middle and lower rectum, usually do not have mesentery. However, since the concept of TME was introduced by Prof. Heald in 1982, especially in recent years, there have been numerous publications and conferences at home and abroad, especially when the surgeon lifts the rectum and pulls it upward during surgery, the “rectal mesentery” does exist and is attached to both sides of the middle and upper rectum with a certain degree of mobility. This fact is slightly different from the previous anatomical concept of “mesentery”, and Professor Heald believes that it is helpful to propose a surgically significant rectal mesentery, which is of great importance for postoperative pathology, and that the “Surgeryre- defininganatomy” should be discussed with anatomists. defininganatomy” by surgery to redefine anatomy.
2. Keys and techniques of total mesenteric resection
Professor Heald used clear anatomical atlas and surgical video to show that the pelvic fascia contains two parts, one covering the surface of the sacrococcygeal bone called the anterior sacral fascia Denonvillier’s fascia, and the other wrapping around the posterior rectal mesentery called the intrinsic rectal fascia. professor Heald emphasized that the key and technique of TME is to fully pull the rectum upward to make its mesentery spreading, and the electric knife under direct vision For resection of high rectal cancer and its mesentery, the lower part should reach 5 cm below the lower pole of the tumor in the intestinal wall; the lateral side of the rectum should be cut at the root of the lateral ligament; the distance from the abdominal aorta and the splenic vein should be 1 cm below the rectum, respectively. The lateral rectum should be cut at the root of the lateral ligament; the submesenteric arteries and veins should be ligated 1 cm below the abdominal aorta and splenic vein, respectively, and the proximal rectal mesentery and the fat and lymphatic tissue contained therein should be removed.
However, Prof. Heald points out that not all TMEs can cut the vessels at such a high level, depending on the length of the patient’s sigmoid colon and its mesentery, which is too short to be suitable, and that the vessels can only be ligated at the root of the superior rectal artery, leaving the left colonic artery and vein intact. He himself is usually able to ligate the root of the submesenteric vessels in only 70% of cases. In other words, does the difference in the plane of vessel ligation affect the extent of mesenteric lymph node dissection, resulting in inconsistent standards of total mesenteric resection in the same group of patients with rectal cancer and ultimately interfering with prognostic evaluation? In about 20% of patients, the ligament is crossed by the middle rectal artery and is located on one side. Japanese scholars describe the ligament as an “onion”, and they advocate lateral lymph node dissection like “peeling an onion” from the inside out. However, Prof. Heald believes that once the tumor invades the intrinsic rectal fascia, any lateral debridement will not help, and likewise, total mesenteric resection will not be able to achieve the purpose of radical cure.
3.The value of total mesorectal resection with inferior rectal margin and frozen section
However, when the author asked about the surgery of low rectal cancer, the intestinal wall is resected 2cm, and the mesentery is resected 5cm, so the intestinal wall is stripped around “too low” or “too light”. “The anastomosis is usually 5-8 cm from the anal verge, and the blood supply to the rectal stump is often maintained by the inferior rectal artery, i.e., the anal artery, so the anastomosis should not be too tight. Professor Heald emphasized that these techniques generally do not result in anastomotic leakage.
For lower rectal cancer, it is usually safe to resect 2 cm of the lower edge of the rectum, that is, during surgery, 1 closure is first put on the lower pole of the rectal tumor 1 cm, and another closure is clamped below it, but it is not struck first, and the intestinal canal is cut off, and it is enough to visually check whether the whole mesentery is intact and the lower cut end is safe. If it is not reliable enough, another closure device is put on and 1 cm of the intestinal canal is resected additionally, and the anastomosis is then completed. Only for patients with low-differentiated adenocarcinoma or intraoperative suspicion of the lower cut margin, or for those with <2 cm lower cut margin, routine frozen margin examination is required.
TME is not suitable for this group of patients. In his own experience, the 5 cm safe inferior rectal margin previously advocated for low-grade rectal cancer can be safely reduced to 2 cm for most well-differentiated rectal cancers, and intraoperative frozen section examination is the gatekeeper for suspicious patients. However, Prof. Heald is more confident in visual observation and surgeon’s finger, and rarely applies frozen section, the trick of operation is to grasp the details.
4. Emphasis on rectum, the unique value of TME
In 1993, Prof. Heald reported 135 cases of Duke stage C patients treated with TME without any other adjuvant treatment, and the local recurrence rate was only 5%. 1998, he reported 465 consecutive cases of rectal cancer, of which 407 cases were treated with TME, and the 5-year and 10-year survival rates were 68% and 66%, respectively, while the 5-year and 10-year local recurrence rates were only 6% and 8%.
Prof. Heald emphasized that postoperative chemotherapy or radiotherapy is often associated with significant side effects and is expensive, except for palliative resection or in patients whose tumors have invaded beyond the intrinsic fascial layer of the rectum and require necessary adjuvant therapy. The correct plane and gap between the anterior sacrum and the rectum are maintained, the rectum, the tumor, the mesentery and its attached vasculature, lymphatic and adipose tissues are completely removed, and the erigentpillar of the erectile nerve column next to the lateral ligament is protected, which can completely achieve the goal of surgical cure alone.
Some scholars once suggested that the ideal radical rectal cancer surgery should achieve the following criteria: cure of tumor, local control, good anal function, and basically normal urination and sexual function. After nearly 20 years of clinical practice, TME can achieve the above requirements more satisfactorily and should be regarded as an ideal surgical technique.
5.Management of special types of rectal cancer
Prof. Heald also discussed one special case of patient especially by video. A female, 42 years old, 24 weeks pregnant, had blood in the stool with difficult bowel movements for 1 week. The examination revealed a concurrent rectal cancer. The patient insisted on keeping the fetus. After discussion with the patient and her family, the treatment team decided to perform a cesarean section for rectal cancer and to continue to maintain the pregnancy until normal delivery. Given the intraoperative enlargement of the uterus, which interfered with the operation of TME, and the high malignancy of the tumor in the postoperative pathology report, chemotherapy was indicated, but there was concern about the impact on the development of the fetus; if chemotherapy was not given, the patient’s prognosis would be unfavorable.
As a result of the coordination between Professor Heald and the patient and the family, chemotherapy was not performed and efforts were made to maintain the health of the fetus. At this point, I asked Prof. Heald whether surgeons in similar situations in the UK need to have some kind of “treatment protocol” to refer to, otherwise it would not be considered a contraindication to “contraindication”. “No”, says Professor Heald, “Thatisusuallybasedonthepatient”, which usually depends on the patient. Thus, it seems that the principles and ethics of medicine are by no means the same, depending on the country and culture. When I asked whether laparoscopic rectal TME could be performed, Prof. Heald said that to really achieve the holyplane empty plane technique required for perfect TME, it is sometimes very difficult to perform a cesarean section, which takes 3-5h, while laparoscopic operation, I am afraid, “notsoeasy,andnotsoreally “is not that simple, not that exact.
6, rectal cancer total mesenteric resection and “Shanghai experience”
At the end of the 20th century, when TME for rectal cancer advocated by Prof. Heald began to be applied in China, especially after this “face-to-face” with Prof. Heald, the authors found, through comparison and reflection, and on the basis of reading a lot of literature, that the surgical operation for rectal cancer in the Department of Abdominal Surgery of the Affiliated Cancer Hospital of Fudan University was consistent with the standard of TME by Prof. Heald. The part of the TME standard of Professor Heald is as follows:1 sharp separation of the rectum under direct vision with electric knife, keeping the intrinsic fascia of the rectum and the holyplane of the anterior sacral space intact; the rectal mesentery at the level of reflexion is cut off at the root of the lateral rectal ligament close to the pelvic wall, and only 15% of patients have the middle rectal artery cut off and tied, and basically no lateral lymphatic clearance is done; the blood vessels are dealt with first after determining the operation style, so as to reduce the possible lymphatic or hematologic dissemination caused by operations near the circumferential tumor such as extrusion. After determining the procedure, the vessels are treated first to reduce the possible lymphatic or hematologic dissemination caused by operations near the circumferential tumor such as compression. And the non-compliant steps are as follows.
(1) ligation of rectal mesenteric vessels at the root of the superior rectal artery only; ligation of one or two terminal sigmoid vessels, as appropriate.
(2) The distance between the lower and middle rectal canal dissection margins is as low as 2-4 cm as possible, provided that a safe anastomosis can be ensured, but a negative dissection margin under intraoperative frozen section is required.
(3) The peri-intestinal fat or tissues below the plane of the distal intestinal canal section, generally only downward separation and resection <115cm, otherwise the anastomosis is too forced is more dangerous, it is too difficult to preserve the anus, then pull out or perform abdominal perineal resection.
(4) Basically, transverse colostomy and J-Poach J-shaped storage pouch are not done. Compared with Professor Heald, different operations have their advantages and disadvantages, and the emphasis is not the same.
7. Problems faced by total mesenteric resection for rectal cancer
When Professor Heald’s 1982 most classic “Themesorectuminrectalcancersurgery-thecluetopelvicrecurrence? During the 5-10 years after the publication of the article in the prestigious British Journal of Surgery, the surgical concept he advocated and the better treatment results he reported were not shared by Western surgeons and oncologists. During this time, Professor Heald traveled several times to Sweden, Norway and Germany in Northern Europe to perform a similar amount of clinical and basic work and came to the same and encouraging conclusions.
In the mid to late 1990s, Professor Heald came to North America, South Africa, Australia and Asia to introduce the technique, and a number of articles were subsequently published, largely agreeing with his views. In the late 1990s and the beginning of this century, there began to be more literature on TME in China and Hong Kong.
When the author talks about the “gold standard surgery” for rectal cancer, it has been stated in the literature that TME will “bury” and “replace” it —However, in fact, the global surgical community is still performing this procedure for a proportion of rectal cancer patients.
”Almost 20 years after the development of TME, there are still in fact some patients with rectal cancer around the world, including his hospital, who require abdominoperineal resection, depending on the patient’s and the surgeon’s understanding of the disease,” but he himself now rarely performs such procedures.
For low rectal cancer, TME has a higher incidence of anastomotic leakage due to the lower mesenteric detachment and poorer blood supply, with a reported incidence of 11%-16% after TME in 219 cases, which is significantly higher than 8% in the non-total mesenteric resection group. In addition, different surgical indications and operation standards directly affect the evaluation of prognosis. There are reports that the average invasion of rectal cancer into the lower intestinal wall is 218 cm, and only 2 cm of the lower edge of the tumor is removed, which is questionable. The value of comprehensive treatment still needs to be studied.
In conclusion, TME of rectal cancer is a very interesting and valuable topic, involving many factors such as anatomy, physiology, pathology, multidisciplinary treatment of surgery and tumor, and prognosis analysis. It is believed that through the unremitting efforts of the Eastern and Western academia, it will contribute to the depth and development of research.