对直肠恶性肿瘤扩散和肛门括约肌机能的病理生理学研究的进展,促进了外科医生在手术中向尽可能保留肛门机能方面而努力——使手术限于直肠结肠切除,保留肛门而又保证不降低疗效。这就要求手术中保留肛门括约肌和必要长度的肛管粘膜。医生面对直肠恶性肿瘤病人,首先需解决三个问题:①施行直肠乙状结肠切除吻合还是连肛门剐除?防止肿瘤扩散的安全界限如何?②为保存肛门自动性和反射性控制机能而又无肿瘤扩散危险,最少需保存多少直肠肛管 Advances in the study of the pathophysiology of rectal malignancy spread and anal sphincter function have prompted surgeons to strive to preserve as far as possible the function of the anus in the surgery - to limit the operation to rectal colon resection, to retain the anus and not to reduce the efficacy. This requires the preservation of the anal sphincter and the necessary length of the anal mucosa. In the face of patients with rectal cancer, doctors need to solve three problems first: (1) To perform rectosigmoid resection and anastomosis or even to remove the anus; (2) To prevent the proliferation of tumors, what is the safety margin? 2) To preserve the anus automatism and reflex control function without tumors Probability of spread, at least how much rectal anal canal