Efficacy and safety of traditional Chinese medicine external washing in the treatment of postoperative wound of diabetes complicated with anal fistula: study protocol of a randomized, double-blind, placebo-controlled, multi-center clinical trial.

INTERVENTION: Intervention group:traditional Chinese medicine external washing;Placebo group:placebo; CONDITION: postoperative wound of diabetes complicated with anal fistula PRIMARY OUTCOME: inflammatory mediator levels;blood glucose;wound pathogen distribution;wound healing; SECONDARY OUTCOME: blood lipid;SF‐36; INCLUSION CRITERIA: 1. Confirmed diabetes mellitus with postoperative anal fistula. The diagnostic criteria for anal fistula will refer to the Guidelines for Clinical Diagnosis and Treatment of Anal Fistula (2006 Edition) jointly formulated by the Colorectal and Anal Surgery Group of Chinese Society of Surgery, Anorectal Branch of Chinese Society of Traditional Chinese Medicine and Specialized Committee of Colorectal and Anal Diseases, Chinese Association of Modern Medicine. 2. Aged 18 to 75. 3. 4cm2 = Postoperative wound area<30cm2. 4. TCM syndrome differentiation is dampness‐heat blood stasis syndromereferring to the People's Republic of China Industry Standard for Traditional Chinese Medicine Diagnosis and Efficacy Criteria for Anal Leakage Syndrome. 5. No previous surgery for anorectal disease, no abnormal anal morphology or function. 6. Voluntary participation and signed informed consent.