Postoperative edema refers to a series of symptoms such as edema, congestion, thrombosis, bulging, swelling or pain in the anal canal and anal margin skin due to local blood and lymphatic circulation disorders, increased vascular osmotic pressure, and excessive water retention in the tissue interstices. In addition to the local inflammatory reaction after surgery, inflammatory edema can be formed at the anal verge. 1.1 In local anesthesia, local anesthetic drug injection is too shallow and overly concentrated, and the injection is not uniform, so that the anesthetic is retained in the subcutaneous tissue space and artificial edema occurs. 1.2 After anorectal surgery, the anal canal and anal margin are compressed by the dressing or the anal sphincter spasms, or too many sutures, which completely close the trauma surface, resulting in blood vessels, lymph vessels and blocking the reflux of blood and lymphatic fluid, resulting in edema from subcutaneous fluid leakage from the anus. 1.3 During the surgery of mixed hemorrhoids, if only the internal hemorrhoids are treated, but the external hemorrhoids are not treated or treated too little, the subcutaneous venous plexus is not stripped, or the incision is decompressed at the end of the circumferential internal hemorrhoid ligation, which causes the anorectal blood circulation to be impaired and edema occurs. 1.4 Anal canal surgery, excision of too much tissue, excessive suture tension, resulting in obstruction of blood and lymphatic return, resulting in edema. 1.5 Post-operative poor urination and defecation, if squatting for too long, or hemorrhoid nucleus prolapsed and embedded, resulting in blood return obstruction and stasis edema. 1.6 Postoperative injury surface secondary infection, increased exudate and tissue edema. 1.7 Stasis edema occurs due to dry stool and obstruction of feces in the rectal jugular, which compresses blood vessels and hinders blood return. 1.8 Some women with loose skin, complete intraoperative excision, well preserved skin bridges, and thorough stripping of the venous plexus are not seen on the second day after surgery, but edema can occur with excessive squatting time. 1.9 Excessive postoperative sitz bath time, prolonged squatting, and high temperature of the sitz bath solution lead to oozing blood or thrombosis edema on the trabecular surface. 1.10 Premenstrual pelvic congestion in women can easily form edema after surgery 2. Prevention 2.1 When injecting local anesthetics, enter the needle at 1cm outside the anal verge, not too shallow and too concentrated drugs should be fan-shaped and evenly injected into the muscle layer tissue. 2.2 The external part of the mixed hemorrhoids should be treated correctly, the incision should be radiolucent, the flap should be aligned neatly, the skin of the external hemorrhoid bulge should be excised thoroughly, and the external hemorrhoid plexus should be stripped completely so that the trauma is drained smoothly. The technique should be gentle and not rough to destroy the normal tissue. The position of the internal hemorrhoid ligation should not be lower than the tooth line to avoid ligating the skin. 2.3 Once the injected or ligated internal hemorrhoid is prolapsed after surgery, it should be ligated and removed in time to prevent edema from occurring. 3.4 When anal fistula and internal hemorrhoids coexist, the internal hemorrhoids should be dealt with first or operated on at the same time as the internal hemorrhoids. Otherwise, if the fistula is removed first, the anal canal will be relaxed and the internal hemorrhoid will easily come out, which will not be easy to reset and return, resulting in edema. 2.5 For those who have difficulty in defecation, they should do a good job of laxation, softening the stool and facilitating urination in time to prevent constipation or flaccid colonic laxation disorders and avoid formation of fecal stones, otherwise squatting too long and defecating angrily can occur edema. 2.6 After anorectal surgery, in general, the patient has frequent urge to urinate, anal down, want to defecate, which is mostly a normal reaction after stimulation, should be due to the patient appropriate control. Pre-operative preparation of the patient’s mind. 2.7 Postoperative bathing solution should be moderate temperature, not too high, close to body temperature is appropriate, as far as possible side position warm compress, not long squatting. 2.8 Women avoid pre-menstrual and post-menstrual surgery. 3, treatment 3.1 local available magnesium sulfate 30 ~ 60g, add boiling water 200 ~ 500m1 dissolved, wet compress the affected area, 2 ~ 3 times a day, each 10 minutes. Or concentrated salt water wet compress 3.2 if belong to the dressing compression is too tight, affecting the local blood, lymph circulation and bruising edema, can be appropriate loose dressing, reduce the local pressure, promote blood, lymphatic reflux. 3.3 Local use of alum lotion, fumigation of the affected area 1~2 times a day, 10~20 minutes each time. 3.4 Topical application of Jingwanhong ointment and Ma Yinglong hemorrhoid nursery to the affected area. 3.5 When there is thrombosis, the thrombus should be removed in time to promote healing. 3.6 If the stool is dry, use topical enemas with open cork or warm salt water. 3.7 Inflammatory edema caused by infection should be anti-inflammatory and analgesic, and antibiotics should be used appropriately, if there is abscess formation, the abscess should be excised in time to prevent the spread of infection. 3.8 Actively change the medication and clean up the secretions of the wound in time.