Rectal cancer is one of the most common malignant tumors in human beings, and about 85% of rectal cancers in China are of the lower segment. Since 1908, when Miles, a British surgical specialist, created the transabdominal perineal radical surgery (APR) for rectal cancer, it has been nearly a century since then. APR has become the accepted “gold standard” for the radical treatment of rectal cancer. Subsequent treatments for rectal cancer must be compared with APR to determine whether they are acceptable or not. However, APR requires the removal of the anus and a permanent abdominal wall colostomy, which causes great harm to the patient’s spirit and psychology as well as extreme discomfort in life, and some patients even refuse the surgery because of this reason. With the in-depth research on the anatomy and physiology of rectum, pathology and biological characteristics of rectal cancer, as well as the development of surgery and instruments in recent years, patients have more opportunities to preserve the anus while the tumor is cured. Therefore, the study of anal preservation surgery for low rectal cancer has become one of the key points in the surgical treatment of rectal cancer, and has gained considerable progress. Ren Hui, Department of Colorectal and Anal Surgery, Second Hospital of Jilin University
In recent years, studies have shown that the lymphatic spread of rectal cancer is mainly upward, especially above the peritoneal fold, and rarely spreads laterally and inferiorly, and only highly malignant or advanced cancer will spread retrogradely downward after the upward lymphatic vessels are blocked by cancer emboli, and most of the spread is less than 2.0 cm. According to the size, location, differentiation, infiltration and general condition of the patient, radical surgery for low rectal cancer that preserves the function of anal sphincter can improve the quality of life of patients. A lot of clinical practice and pelvic floor trial studies have shown that as long as the anal canal, anal sphincter and anal levator muscle are preserved intact, the anus can be preserved and normal defecation function can be maintained. It is also common to see people who seem to be unable to preserve the anus, but after sufficient intraoperative freeing of the rectum, the anus can be preserved. The shape of rectum is not straight in the pelvic cavity, but the lower 1/3 of it runs in an arc against the anterior sacral recess. When the rectum is fully freed and the bilateral lateral rectal ligaments are cut, it can be extended by about 3 cm, which provides favorable conditions for anal preservation surgery.
(1) Transabdominal proctocolectomy (Dixon surgery) Dixon surgery preserves part of the lower rectum and the complete anal canal, the internal and external anal sphincter and its innervated nerve and anal levator muscle, which is the most satisfactory surgery for controlling defecation function after preserving the anus among all kinds of rectal cancer radical surgery. The double anastomosis method of low anterior resection (LAR) and the developed coloanal anastomosis (CAA) are considered to be the new advances in the surgical treatment of rectal cancer in the 20th century. The introduction of the double anastomosis has made deeper operations easier. Therefore, the double anastomosis technique is one of the more advanced methods in rectal cancer anus-preserving surgery at present.
Total rectal mesenteric resection with preservation of vegetative nerve is performed in radical rectal cancer surgery. It refers to the preservation of the inferior abdominal nerve plexus when freeing the rectum, and after the ligation of the inferior mesenteric vessels, the left and right sides of the sigmoid mesentery have been opened, and the sigmoid colon is lifted forward and sharply separated from the loose tissue between the presacral fascia and the intrinsic rectal fascia to the tip of the tailbone under direct vision, thus keeping the intrinsic rectal fascia wrapped by the fascia intact, which is currently considered the most valuable measure to reduce the local recurrence rate. This is because even if the lymph nodes are not invaded, there are still nests of adenocarcinoma cells hidden in the rectal mesentery. If blunt separation is performed, not only is the resection of rectal mesentery incomplete, resulting in residual cancer, but it is also very likely to cause cancer cell spreading and implantation.