Rectal prolapse is a condition in which the rectum, anal canal, and even part of the sigmoid colon descend and prolapse. It is common in the young and elderly, and often causes painful symptoms such as fecal incontinence. The initial cause is still not well understood and is the subject of much debate, but there are two popular theories, namely the sliding hernia theory and the intussusception theory. Surgery is still the main means of treating rectal prolapse, and there are two ways: transabdominal and perineal, with more than 100 transabdominal and dozens of perineal surgeries. 1.Delorme’s operation, that is, trans-perineal rectal mucosal resection and folding and suturing of the intestinal wall muscle layer. Delorme et al. proposed in 1900, he made a rectal mucosal sleeve resection outside the anus, and the prolapse was completely removed, saline was injected under the mucosa, the mucosa was circumferentially cut 1-2 cm from the dentate line to the submucosa, the mucosa was separated from the muscle layer into a sleeve shape until the top of the prolapse, and the mucosa was completely removed. Six sutures are then passed through the mucosal edge at the base of the prolapse and through several muscular layers, and then through the top mucosal edge. This procedure is mostly used to treat endoprostheses. It is ideal for small low prolapses and is also suitable for elderly and frail patients with limited life expectancy and prolapse symptoms. Satisfactory results have been reported by Senapati et al. who performed this procedure in 32 patients from 1978 to 1990, with a duration of 2 wk-10 years, with no postoperative loss and 4 recurrences during a mean follow-up period of 24 mo, with a recurrence rate of 15%. They concluded that although the recurrence rate of this procedure is higher than that of transabdominal rectal fixation (5%), there is no risk of opening the abdomen. Moreover, the Delorme procedure has a better long-term bowel function recovery compared to the high incidence of constipation (40%) after transabdominal rectal fixation. Tsunoda et al. [concluded that this procedure did not cause constipation and that it improved the sensory function of the anal sphincter and rectum, probably because it reduced the incidence of postoperative constipation. However, there are some unsatisfactory aspects of this procedure, as it has a high long-term recurrence rate, probably due to the fact that only part of the prolapse was removed without treating the underlying anatomical defect. It also does not treat the pelvic floor and outlet defects, and postoperative perineal descent persists. Watkins et al [3] performed a modified Delorme procedure in 52 patients with a mean prolapse length of 8.2 cm in 1975/2001-12 and a mean follow-up of 61.4 mo. 12 of them had incontinence before surgery and 10 of them improved after surgery. The incidence of prolapse at 5 years after surgery was 6% (3/52), and the overall recurrence rate at the end of 26 years was 10% (5/52). The incidence of complications was 4%. The recurrence rate was reduced with the implementation of appropriate modifications, and the procedure was safe for those with significant complications. Altemeier’s procedure is a partial transepithelial rectosigmoidectomy. This procedure was originally described by Mikulicz in 1889, and the most popular one is the modified perineal resection done by Altemeier et al. in 1971. He reported 106 patients with no postoperative deaths and only 3 recurrences. Kimmins et al. followed 63 patients for an average of 20.8 mo in 1993-02/1999-12. 70% of the patients had local anesthesia, the average resection length was 11.6 cm, and 83% of the patients used an anastomosis. The recurrence rate was 6.4%, and patients with recurrence could undergo this procedure again. Complications were low (10%). The procedure can be performed on an outpatient basis because 80% of patients can be discharged within 24 hours and do not require general anesthesia. Although the recurrence rate is slightly higher than that of transabdominal resection, the morbidity and cost are low, and the procedure can be easily and safely repeated. Habr-Gama et al. retrospectively analyzed 44 patients with rectal prolapse who underwent perineal rectosigmoidectomy with anal levator repair from 1985 to 2000. The mean duration of disease was 29.2(1-40) mo. The mean length of rectal prolapse was 8.3 cm and the mean length of resected bowel segment was 21.2 cm. The complication rate was 9.1%. There were no fatal cases in this procedure. The average length of stay was 3.9 d. During the average follow-up period of 49 mo, the recurrence rate was 7.1% (recurrence of prolapse in 2 patients and prolapse of rectal mucosa in 1 patient). Satisfactory functional improvement and an acceptable low recurrence rate were achieved in 36 patients (85.7%). For surgical instrumentation, Boccasanta et al [8] performed conventional monopolar electrocautery with manual anastomosis and scalpel and circular anastomosis in 58 patients in 1999-01/2003-12 and showed that the clinical and functional long-term outcomes of transperineal rectosigmoidectomy with myoplasty were not affected by surgical instrumentation or type of anorectal anastomosis. In high-risk patients, clinically pertinent short-term outcomes should be clearly studied. In addition, there is no risk of anastomotic fistula or pelvic abscess due to suspension of the support material, and no genitourinary problems associated with transabdominal surgery, but long-term results are poor, with a high recurrence rate of approximately 5-20%. It is mainly suitable for those who are too old and frail to tolerate transabdominal surgery and those who have long prolapsed bowel segments, cannot be repositioned or have necrosis of the intestinal canal. 3.Thiersch’s operation is the anal canal loop reduction. In 1891, Thiersch first implanted a silver wire ring under the skin of the anal canal to tighten the relaxed anal sphincter and removed it 12 wk later. This procedure can be done under local anesthesia and is simple and less invasive. However, it cannot remove many causes of rectal prolapse, and complications such as fecal impaction, fracture or relaxation of the implanted ring, ulceration and infection at the place of ring placement, and acute prolapse occur, which are unsatisfactory and have a high recurrence rate. Later, surgeons tried many materials to improve this procedure, such as fascia, tendon, nylon, polypropylene, Teflon, etc., which are less prone to rupture and have fewer complications. Khanduja et al. modified this procedure by replacing the silver wire ring with a silicone ring and treated 16 emergency patients, all of whom were able to correct their prolapse. Therefore, this procedure is an old and practical one. In recent years, Gupta has described that this procedure combined with perineal subcutaneous coagulation-induced fibrosis for prolapse is more effective in older adults who are at greater risk for other surgical procedures. At 2 years of follow-up, two cases had complications, one of which was due to sepsis at the coil placement and required removal, and one of which had coil relaxation. Three cases recurred, one of which complained of fecal incontinence. It can be seen that this procedure has few indications, and it can be used as an adjuvant palliative treatment for mild rectal prolapse and for those who are too old and frail to tolerate other procedures. Gant (1923) treated complete prolapse with mucosal ligation and anal canal narrowing. Miwa (1966) popularized this procedure. The prolapse is first completely removed from the anus, the mucosa and submucosa are held up with a hemostatic forceps, and a non-absorbable suture is passed through the submucosa with a curved needle and ligated around the tip of the forceps to form a large mucosal node. Starting from the uppermost part of the prolapse, a circular ligature is made around the prolapse, with 4-6 nodes in each loop up to the top of the dentate line. The number of mucosal nodes varies according to the size of the prolapse, some up to 100, shortening the mucosa and reducing the prolapse. The prolapse is then retracted and a subcutaneous reduction of the anal canal is performed. Although this procedure is described in English textbooks, it is rarely used. In Japan, this procedure together with anal loop reduction has played a major role in the treatment of rectal prolapse since 1960. Yamana et al. suggested that the details of the technique (e.g., use of the Teflon band and the route relative to the deep side of the external dilator and the outside) play an important role in the success of the procedure. The results showed recurrence rates of 0%-31%, no deaths, and essentially no complications such as hemorrhage and severe sepsis. In addition, anal resting pressure and rectal sensation improved, which is a positive effect on bowel function. Therefore, we believe that this procedure with anal loop reduction is a better choice among perineal procedures. Arakawa (1979) reported treating 206 cases of complete prolapse, with a recurrence rate of 14%. Since Longo invented the procedure of produce of prolapse and hemorrhoids (PPH) for the treatment of severe internal prolapse in 1998 and used it in clinical practice, the domestic literature has reported the application of PPH with anastomosis for the treatment of internal prolapse with good results. PPH has been used to treat rectal mucosal prolapse with remarkable results. Zhang Lianyang et al. performed PPH on 42 patients with rectal mucosal prolapse, and the total effective rate was 88.1% (37/42), of which 81.8% (18/22) was for endorectal mucosal prolapse and 95.0% (19/20) was for extrarectal mucosal prolapse, which proved that PPH was better than endorectal mucosal prolapse in the treatment of extrarectal mucosal prolapse. Zheng Xin et al [16] reported that two cases of prolapsed rectal mucosa after surgery had heavy preoperative symptoms, so it was suggested that double purse-string sutures should be performed in such patients, and it was also reported that this procedure could improve the symptoms of rectal prolapse. Wang Benjun measured the reflexion distance (the “S” shaped distance of the maximum free edge from the tooth line) after locating the tooth line, and then performed double purse-string sutures at 6 cm and 5 cm above the tooth line after exploring clearly. After surgery, the patient was treated with a long-term maintenance “package” to regulate the patient’s physical condition as a whole, with a total clinical efficiency of 93.3% and a total efficiency of 85.7% at 3 mo postoperative follow-up. Ma Hui’s double purse-string suture is 3-4 cm from the distal suture line to the dentate line and 1.0-1.5 cm from the proximal suture line to ensure that enough circular mucosa is removed to cause adhesions between the mucosa and the muscle layer for the purpose of treating endorectal prolapse, and the width of mucosa removed is 4-6 cm. All patients’ clinical symptoms basically disappeared and the patients felt satisfied. It has also been reported that longitudinal suturing of the rectal mucosa 6-8 cm in the parent hemorrhoid area at points 3, 7 and 11 on the dentate line during PPH can reduce postoperative recurrence and relieve defecation difficulties. For external prolapse, Qiu Lei et al. also achieved good results after PPH with three-point mucosal columnar sutures in the parent hemorrhoid area and high perirectal injection of hemorrhoid eliminating agent. All of them were cured after 6-18 mo of postoperative follow-up. For grade II and III rectal prolapse, double purse-string anastomosis can also achieve good results [21]. The PPH procedure for rectal prolapse is simple, with few complications and short healing time. The mechanism is that the inflammatory reaction causes fibrosis of the perirectal tissues, which leads to fixation of the rectal wall with the surrounding tissues, thus preventing the occurrence of prolapse. The choice of sclerosing agents includes: 5% glycerol petrolatum, 1% castor oil petrolatum, 1% quinine and urea hydrogen chloride, 70% ethanol, 30% saline, 25% saline, 50% dextrose, milk, each with different cure rates and complications. Some dosage forms are effective but have more complications, some do not have complications but have low cure rates, and some are effective and do not have complications but are difficult to inject. Shah et al [23] reviewed 17 patients under 5 years of age from 1995 to 2003 who were treated with submucosal hypertonic saline, with a cure rate of 14/17 (83%) with a single injection and 3 cases of sclerotherapy failure due to allergy to cow’s milk protein (CMP) in the diet. Abes et al. concluded that injection of hypertonic solution directly into the intestinal mucosa would cause mucosal cell damage, so a 15% relatively hypotonic solution was chosen instead of 30% to treat prolapse. In 1992-06/2003-05, a 15% saline solution was administered to 16 children. The patient was placed in a lithotomy position under general anesthesia, and the operator’s left index finger was placed in the anus for guidance to control the needle position. The submucosal tissue, the right perirectal area, the left perirectal area, and the posterior rectal area were selected, and the needle was inserted through the perianal skin, and saline was injected slowly while retracting the needle. The anterior rectal wall was not injected because it was close to the bladder neck. After the injection, the patient was discharged and given a stool softener to prevent constipation. The result was a primary cure rate of 15/16 (93.7%), with only one case requiring a second injection. Sasaki et al. treated 9 children (aged 5-14 years) with almond oil lithate injection for rectal prolapse. Postoperative anorectal manometry revealed normal anorectal reflex and other parameters after injection. Of the four patients who had complained of constipation, two had resolution of symptoms. Fahmy et al. compared the injection results of 98% normal ethanol, 5% almond oil lithate injection and dextranomer/hyaluronic acid copolymer (Deflux), which showed no mucosal necrosis and abscess formation with Deflux and no recurrence at long-term follow-up. The results showed no mucosal necrosis or abscess formation with Deflux and no recurrence at long-term follow-up. Ethanol is cheaper and more readily available and can be used as an alternative to Deflux. Hachiro et al [27] in 2005-10/2006-06 treated 14 adults with complete rectal prolapse [age 34-91 (mean 76) years] with sclerotherapy of potassium aluminum sulfate and ellagic acid injection. During a mean follow-up period of 6 mo, all 14 patients were cured without intraoperative or postoperative complications. Only one case required a second injection. There was no increase in constipation and no stricture. 7/10 patients with fecal incontinence had relief of symptoms. Professor Huang Naijian, a famous anorectal expert in China, through the collection of rectal prolapse animal specimens and the establishment of animal models, proposed that the essence of human rectal prolapse is rectal and rectal overlap, and its prolapse plane is mostly in the rectal jug abdomen, and its position is relatively constant. In contrast, the sigmoid colon is inserted into the rectum, which is the result of the aggravation of rectal prolapse, that is, due to the gradual development of the disease, the lower intestine prolapses and involves the higher intestine to descend. This is the reason why the combination of Chinese and Western medicine with alum injection therapy can cure the prolapsed intestinal canal up to 15 cm in length. In addition, for complete rectal prolapse, Li Huashan et al [29] reported good results by using double-layer 4-step injection therapy with anti-hemorrhoid injection. The so-called double-layer 4-step injection therapy refers to the injection of the outer rectal layer (perirectal space) and the inner rectal layer (submucosal layer) in 4 steps. The medication (e.g., anti-hemorrhoid injection) is injected into: (1) both sides of the pelvic rectal space: to fix the adhesion between the rectum and the lateral rectal ligament; (2) the posterior rectal space: to fix the adhesion between the rectum and the anterior sacral fascia; (3) the submucosal layer of the rectum: to fix the adhesion between the loose rectal mucosa and the muscle layer, so as to achieve the treatment purpose. In addition, Zhang Yansheng et al [30] reported that subrectal mucosal injection and suture to produce scar support fixation, perirectal high interstitial injection of hemorrhoidal sclerosing agent, and anal canal tightening to seal the caudal triangle to achieve effective treatment of complete rectal prolapse and reduce the possibility of recurrence by single injection. It can be seen that the treatment of complete rectal prolapse can be enhanced by combining the traditional injection therapy with some auxiliary treatment measures, such as anal loop reduction, tightening, sphincter folding [31], and scar rectal fixation, to achieve a higher goal of one-stage cure. 7. Conclusion Rectal prolapse is still a difficult problem, because its pathogenesis is the result of a combination of factors, there is no clear and effective treatment option, and surgery is still the main means to cure this disease. (5) elimination of the Douglas cavity; (6) repair of a sliding perineal hernia. Theuerkauf et al. combined the results of various surgical procedures for rectal prolapse, with a total of 3?505 cases treated, 48 deaths, 2?858 cases followed up, and 480 recurrences. Among them, 54 Altemeier procedures were performed without death, 54 cases were followed up, and 2 cases of recurrence; 336 Delorme procedures were performed, 8 cases of death, 328 cases were followed up, and 82 cases of recurrence. The variety of surgical approaches also demonstrates that no single approach is suitable for all patients, and the evaluation of the merits of each approach requires a large number of randomized controlled trials. Raftopoulos et al. observed the recurrence rate of 643 adults with complete rectal prolapse after transabdominal surgery in a long-term multicenter follow-up and found that the average recurrence rate was 1.06% at 1 year, 6.61% at 5 years, and 28.92% at 10 years after surgery. There was no significant effect of different medical units, surgical approaches, surgical methods and surgical techniques on the postoperative recurrence rate. Kim et al. followed up 372 adults with complete rectal prolapse (1976-1994) and found a recurrence rate of 5.1% (mean follow-up 98 mo) for transabdominal surgery and 15.8% (mean follow-up 47 mo) for perineal surgery. Transabdominal surgery has a low recurrence rate and is ideal for young, strong patients. However, abdominal surgery requires either free or fixed rectum, or resection of colon, or both, so the complications are relatively high, such as infection, anastomotic leak, and mortality. In the treatment of rectal prolapse in China, injection therapy has been widely used, especially for the treatment of complete rectal prolapse in adults with elimination of hemorrhoid injection, which is a double-layer 4-step injection method or perirectal injection, or injection with PPH and anal tightening, all of which have achieved better results. Injection therapy has many advantages such as no pain, few complications, short hospitalization time, low medical cost, and reusability. However, its efficacy is closely related to the drug dose, concentration, injection method and number of injections. Moreover, there is a lack of randomized controlled studies or cohort studies with large samples of open or other perineal procedures, and long-term clinical follow-up analysis. The long-term efficacy is the key to evaluate this therapy. In conclusion, the selective use of various procedures can greatly improve the efficacy of the treatment compared with the use of a single procedure. Further research on the pathogenesis of rectal prolapse, differentiation of different types of rectal prolapse, and the establishment of individualized treatment plans may be important directions for future research. 8