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: the sliding hernia theory and the intussusception theory. Surgery is still the main treatment for rectal prolapse, with both transabdominal and transperineal approaches, and more than 200 methods, but “none of them are satisfactory”. Injection therapy was once “rejected” by people because of its high recurrence rate; however, it is gaining attention because it does not destroy the anatomical structure and physiological function of the rectum and colon, and does not have a series of complications caused by open or trans-perineal surgery. The progress of injection therapy for rectal prolapse is outlined below. 1, injection therapy drug selection Commonly used injection drugs are alcohol, 50% glucose, saline, milk, almond oil of petrocarbonate, 5% sodium cod liver oil, different concentrations of alum injection, peony times injection, anti-hemorrhoid injection, etc. The cure rate and complications of each drug are different. Some drugs have high cure rate but more complications, such as alcohol, almond oil of petrocarbonate, etc.; some drugs have less complications but low cure rate, such as saline, 50% glucose injection; some drugs are very effective and have few complications but require high injection technique, such as alum injection and anti-hemorrhoid injection. Qiu Yuhong et al [2] used 950 mL/L ethanol, Bahador et al [3] used 960 mL/L alcohol to treat pediatric rectal prolapse, Xu Dongsheng [4] used 50% glucose to treat anorectal prolapse, Wang Changjiang and Zhu Wenqiang [5] applied 5% cod liver oil sodium acid injection, Zganjer et al [6] used milk to treat rectal prolapse in infants and children, Sasaki et al [7 [8] used hypertonic saline for the treatment of rectal prolapse in children, Guiquan Ren and Ming Wang [9] used Paeonibe injection for the treatment of rectal prolapse in the elderly, Yu Duo [10] used 8% compound alum injection (alum 6 g, Huanglian 2 g, sodium citrate 1. 5 g, procaine hydrochloride 1 g, made up of 100 mL solution), Huashan Li et al [11, 12], Bao Han [13 et al [13] used the antihemorrhoid injection to treat complete rectal prolapse in adults, etc. In conclusion, with the development of injection therapy, the injectable drugs have been gradually expanded from the original Western medicine preparations to pure Chinese medicine preparations such as Paeonia Bui injection, as well as the combined Chinese and Western medicine formulations such as various alum preparations and anti-hemorrhoid injection. However, due to the increasing standardization of national drug requirements, some traditional preparations such as various compound alum injections have been banned from being injected into human body because they cannot meet the standards of new drugs listed on the market, and some drugs have been gradually eliminated. 2, injection therapy method selection Commonly used injection methods are rectal submucosal injection method, perirectal injection method, perianal injection method, point injection method, column injection method, fan injection method, two-way injection method, high and low injection method and so on. For example, Qiu Yuhong used perirectal injection, Xu Dongsheng used 50% dextrose circular submucosal injection, Wang Changjiang and Zhu Wenqiang used perianal injection, Yu Duo used subrectal mucosal and perirectal gap injection for rectal prolapse, Li Rizeng used subrectal mucosal injection and pelvic rectal gap injection, Yan Shuhua used column injection, Zhang Zhitao used subrectal mucosal dot injection and rectal Li Huashan et al. used double-layer four-step injection of eliminating hemorrhoids, Han Bao et al. used simple intra-rectal injection for degree I prolapse, and intra-rectal plus extra-rectal injection for degree II and III. 3, the indications of injection therapy Foreign scholars mostly use injection therapy to treat infants and children and incomplete rectal prolapse; domestic scholars apply injection therapy to all kinds of rectal prolapse. For example, Zganjer et al. used milk to treat rectal prolapse in infants and children, Sasaki et al. used almond oil of petrocarbonate injection to treat pediatric rectal prolapse, Bahador et al. used 96% alcohol injection to treat primary rectal prolapse in infants and children, Hachiro et al. used potassium aluminum sulfate tannic acid injection to treat rectal prolapse, Li Huashan et al. used double-layer four-step injection of elimination of hemorrhoids to treat complete rectal prolapse in adults The treatment of complete rectal prolapse in adults was carried out by a four-step, double-layer injection of Hemorrhoid Remover, and Han Bao used Hemorrhoid Remover to treat rectal prolapse, including degree I, II and III rectal prolapse. 4, the efficacy and safety of injection therapy The literature reports that injection therapy has achieved good efficacy, and fewer complications, with considerable safety. For example, Qiu Yuhong used 95% ethanol for perirectal injection to treat 32 cases of pediatric rectal prolapse, and the symptoms disappeared in 25 cases, and 7 cases were cured after the second injection. Two children had transient fecal incontinence after surgery, and one case had urinary retention. Xu Dongsheng treated 11 cases of rectal prolapse using 50% glucose circular dot injection into the submucosa, with a cure rate of 64% (7 cases) and a total efficiency of 91% (10 cases). Wang Changjiang and Zhu Wenqiang applied 5% cod liver oil sodium acid injection for perianal injection in 38 cases, among which 2 cases had acute enteritis caused by improper diet after injection, resulting in failure of the first injection, which was cured by two injections, and 3 patients had difficulty in urination. Zganjer et al. used milk to treat 86 cases of rectal prolapse in infants and children and showed a cure rate of 95.3% (82 cases), while the remaining 4 cases were treated surgically. Sasaki et al. treated 9 cases of rectal prolapse in pediatric patients with almond oil injection of petrocarbonate, and all 9 patients were cured without any complications. Shah et al. used hypertonic saline submucosal injection to treat 17 cases of rectal prolapse in children, with a cure rate of 83% (14/17), and 3 cases failed due to allergy to cow’s milk protein in food, and concluded that hypertonic saline injection was effective in early idiopathic rectal prolapse in children. Abe et al [18] concluded that hypertonic saline caused intestinal mucosal cell damage and confirmed that 15% saline injection was desirable because of its ease of operation, high safety and few complications, with a one-time cure rate of 93.7%. Bahador et al. used 96% alcohol injection to treat 165 cases of primary rectal prolapse in infants and children with satisfactory results. Fahmy et al [19] compared the effect of using 980 mL/L alcohol, 5% phenol almond oil and dextranomer/hyaluronic acid copoly-mer (Deflux) in the treatment of rectal prolapse in children and showed that Deflux injection had the lowest complication rate with no recurrence at long-term follow-up. Almond oil with 5% phenol is not preferred for treatment because of its high complication rate. Alcohol 980 mL/L is a cheap alternative to Deflux injection. Hachiro et al. treated 14 cases of rectal prolapse with potassium aluminum sulfate ellagic acid injection and all were cured without intraoperative or postoperative complications. One patient required repeat injections 1-2 mo later to cure. Ren Guiquan and Wang Ming [9] treated 20 cases of rectal prolapse in the elderly with Paeoniflora injection, 19 cases were cured and 1 case was improved, with a total effective rate of 98%. Yu Duo used 8% compound alum injection (alum 6 g, Huanglian 2 g, sodium citrate 1.5 g, procaine hydrochloride 1 g, made into 100 mL solution) to treat 63 cases of rectal prolapse by injecting into the rectal mucosa layer and perirectal space, with 100% efficiency and no recurrence in 3 years of long-term effect. Li Xin et al. also used homemade compound alum solution to treat 102 cases of rectal prolapse, with submucosal injection for rectal mucosal prolapse and perirectal interstitial injection for complete prolapse. Other types of alum preparations include compound alum injection, 5% alum injection, self-designed prolapse solution (6% alum injection) [23], and 12% alum solution, etc. The overall cure rate reached 100% after multiple injections, and no serious complications occurred. However, I have treated a case of total rectal necrosis after perirectal injection with 7% alum injection, and finally a permanent sigmoid colostomy had to be performed. It can be seen that if the choice of drugs and dosage is not appropriate, or improper injection methods, serious complications may occur. Since the invention of the hemorrhoid elimination injection at Guang’anmen Hospital of the Chinese Academy of Traditional Chinese Medicine in the 1980s, a breakthrough has been made not only in the treatment of hemorrhoids, but also in the treatment of rectal prolapse. In the past 10 years, the literature on the treatment of rectal prolapse with the injection of anti-hemorrhoid spirit is the most abundant, and it has generally achieved better efficacy. Li Huashan et al. treated 36 cases of complete rectal prolapse with a double-layer four-step injection of Hemorrhoid Ling, and the concentration of Hemorrhoid Ling injection was studied. The method was to randomly divide 36 patients into two groups A and B. Twenty cases in group A were in the high concentration group and 16 cases in group B were in the low concentration group. The results showed that 19 cases were clinically controlled in group A and 1 case was effective; 16 cases were clinically controlled in group B. No significant difference was found in the recent efficacy of the two groups. After 3-36 mo follow-up, there were 7 cases of relapse. Four of the relapsed cases were clinically controlled by re-injection of high concentrations, one by open colectomy, one by open rectal suspension and one by anastomotic loop rectal mucosal resection (PPH procedure). Although no significant effect of drug concentration on the recent and long-term efficacy was observed in this study, a positive correlation between efficacy and drug concentration was found in long-term clinical work, i.e., the higher the concentration, the better the efficacy. Han Bao et al. treated 266 cases of rectal prolapse with anti-hemorrhoid injection, and evaluated the injection site of the injection method. There were 158 cases (43.9%) with intra-rectal injection alone and 108 cases (56.1%) with intra- and extra-rectal injection. The results were cured in 263 cases (98.9%) and improved in 3 cases (1). 1%). There were no complications such as rectal stricture, haemorrhage, intestinal obstruction and infection. Li Rizeng treated 46 cases of prolapsed rectum with antihemorrhoid spirit, and only rectal mucosal injection was performed in Ⅰ degree prolapse, while rectal mucosal injection and pelvic rectal gap injection were performed in Ⅱ-Ⅲ prolapse. The results showed that 42 cases were cured at one time, 2 cases were improved, 0 cases were ineffective, 2 cases were cured after 2 injections, and no serious complications occurred. Zhang Zhitao used 1:1 subrectal mucosal spot injection of elimination hemorrhoid injection and high and low level injection around the rectum to treat adult complete rectal prolapse. The purpose of high level injection is to inject the medicine into both sides of the rectal pelvic gap and presacral gap; the purpose of low level injection is to inject the medicine into the lower part of the rectal prolapse sulcus. The injection point was at 3, 6 and 9 points from the anus at 1.5 cm from the truncated position. As a result, 25 cases were cured in one time, with a cure rate of 100%, and no recurrence was seen in the follow-up period of 3 years. It can be seen that the injection method, such as the injection site and the amount of drug used, has an important impact on the efficacy. For patients with severe prolapse (degree II and III), extra-rectal injection not only reduces the chance of infection, but also strengthens the adhesion and fixation between the rectum and the surrounding tissues, which significantly improves the efficacy after surgery. As we can see above, only by using different concentrations and different sites of injection methods of eliminating hemorrhoids for different degrees of rectal prolapse can we achieve better therapeutic effects. For rectal prolapse in children, there are many reports of injection therapy in the foreign literature, but there are no reports of treatment with Hemorrhoid Injection, probably because Hemorrhoid Injection is not yet available in the international market. In China, subrectal mucosal injection is often used for rectal prolapse in children, and if necessary, perirectal interstitial injection is also used. Xi Yanjun et al. treated 32 cases of pediatric rectal prolapse with subrectal mucosal punctal injection and perirectal interstitial injection with the solution of elimination of hemorrhoid injection; the result was that all 32 pediatric patients were cured at one time, and no recurrence was seen in all cases with 1-2 years of follow-up and no sequelae. Ye Ping [26] treated 20 cases of pediatric rectal prolapse with submucosal punctiform injection of elimination of hemorrhoids (1:1) injection with rectal interstitial injection; the result was that all 20 cases were cured at once, and no recurrence was seen after 1 year of postoperative follow-up. 6, other injection therapy Tang Xegang, etc. used ZT medical mucus coated adhesive injection in the pelvic rectal space and rectal posterior space, the treatment of Ⅱ degree rectal prolapse 13 cases. The medical adhesive was injected into the body to produce a strong adhesive force to fix the tissue and achieve the purpose of treatment. There were no obvious complications after the operation, except for 2 cases that needed second injection, the remaining 11 cases were cured in one time, and there was no recurrence at the follow-up for 2 years. Lv treated 134 cases of prolapse with perianal injection of tonic Zhong Yi Qi injection plus ion introduction, injecting 8-10 mL of this product into each of the puborectal muscle, anal levator muscle and pubococcygeus muscle at points 2, 4, 8 and 10, respectively, 2 cm from the anus, and reducing the amount for children, once every 5 days. The results were 119 cases cured, 12 cases effective, 3 cases ineffective, total effective rate 97.7%. 7, injection combined with other therapies for severe rectal prolapse, or comorbidities of rectal prolapse, injection alone is sometimes difficult to achieve the best results, while with some simple treatment often better results, the domestic literature have a lot of reports on this. Yan Shuhua made a 1:1 mixture of antihemorrhoid injection and 0.5% lidocaine, and administered columnar injections at 3, 6, 9, and 12 points, with a volume of 5-10 mL per injection, and ligated the loose mucosa at 3, 7, and 11 points of the distal anorectal junction, and injected the liquid under the mucosa between the ligated points to constrict the anal canal in 76 patients with complete rectal prolapse (degree II and III). All 76 cases were cured after 14-d review. Two cases of recurrence after 2 mo were treated by simple injection again, and the symptoms disappeared after 7 d. There was no recurrence after 1 year of follow-up. Zeng Hui et al. treated 23 patients with grade II or grade III rectal prolapse with 1:1 hemorrhoid eliminating spirit diluted solution by spot injection and interstitial injection plus multi-point ligation of rectal mucosa. The results showed that all 23 cases were cured at the time of discharge, and the average hospital stay was 8.9 d. The follow-up period was 1-2 years, and no sequelae such as recto-anal stenosis, colonic dysfunction, defecation disorder and sexual dysfunction were observed. In 23 cases, the anal sphincter function was also improved in different degrees compared with that before treatment. Peng Wen et al. treated 13 cases of complete rectal prolapse (degree I and II) with 20 mL of hemorrhoid elimination dilution (1:1 preparation of hemorrhoid elimination and saline) injected into the bilateral pelvic-rectal gap combined with anastomotic proctocolectomy (PPH), and the results showed that 13 patients had smooth defecation, no mass prolapse, basically no pain, or only mild swelling. All of them were cured without complications and sequelae, and there was no recurrence at 1-6 years of follow-up. Hou Chaofeng et al [31] treated patients with complete rectal prolapse with PPH using a 1:1 anti-hemorrhoid injection with three interstitial injections of 10-15 mL per interstitial, and the result was that 28 patients had no prolapse and complete retraction after the first defecation. The result was that 28 patients had no prolapse and complete retraction after the first defecation. There was no anal incontinence, hemorrhage, perianal infection and anal canal stricture in the whole group. Yao Jian et al [32] used a combination of connected submucosal injection, perirectal gap injection and anal retraction to treat third degree rectal prolapse. The results showed that all 15 cases were clinically cured, 11 cases were followed up, 10 cases were recurrence-free from 2 to 8 years, 1 case was mildly recurred after 6 months, and 4 cases were lost. Luo Hu [33] treated 38 cases of complete rectal prolapse by submucosal injection plus anal loop reduction, and the cure rate was 95%, which was significantly higher than the 79% cure rate by submucosal injection treatment alone or anal loop reduction alone. The results showed that 34 cases were cured after treatment, and one diabetic patient was cured after removal of sutures and adequate drainage due to incision infection. There was no prolapse, no rectal mucosal necrosis and no anal stricture. After follow-up for 1-6 years, 33 cases were cured, and 2 cases developed incomplete mucosal prolapse within 6 months after surgery, which were cured after re-injection of antihemorrhoid spirit. Shao Feng et al. treated 32 cases of rectal prolapse with a triple procedure (rectal mucosal columnar ligation + anal reduction + haemorrhoid injection), and all patients were cured recently with an average duration of 17 d. There was no recurrence at 0.5-2.0 years of follow-up, and no postoperative complications or sequelae were observed. Chen Meng et al. used a modified triple procedure (rectal mucosal alignment ligation + anal loop reduction + perihemorrhoid injection) to treat 25 patients with complete rectal prolapse, and all 25 patients were cured, with no recurrence and satisfactory results. The combined treatment of injection therapy also includes Chinese herbal medicine formula and drug fumigation, or combined with acupuncture treatment, etc. The postoperative cure rate was 84.6%-100.0%, and the overall efficiency reached 100%. Because of the complex pathogenesis of rectal prolapse, the treatment methods are diversified to solve the problem of rectal prolapse from different aspects. For example, multi-point ligation of rectal mucosa can effectively tighten and fix the loosened prolapsed mucosa, and at the same time form multiple dotted scar bands in the submucosa of the prolapsed lateral wall, which has the effect of scar fixation and fighting against intussusception. The PPH procedure directly removes the excess loose rectal mucosa and narrows the rectal cavity, while the stimulation of the titanium staple causes the mucosa to adhere closely to the muscle layer and strengthens the whole rectum. Anal tightening is suitable for patients with prolapsed rectum who have weak anal contraction or loose anus, especially for elderly and frail patients who are not suitable for larger surgery. The external sphincter folding method is designed for elderly patients with loose rectal mucosa, enlarged intestinal cavity with anal relaxation, weak contraction and even anal incontinence. It can also enhance the tension of the sphincter muscle, which can make the anus position moderately forward and blunt the rectal angle, thus enhancing the pelvic floor’s supporting effect on the rectum. In conclusion, due to poor control of injection concentration and dose, the postoperative effect may not be good or serious complications may arise, but the combination of PPH, ligation therapy, anal loop reduction and external sphincter folding can reduce surgical complications and improve surgical efficacy. 8. Problems From the literature, we believe that the following problems remain to be solved in injection therapy. Second, the injection method is not perfect, the current injection method mainly includes two major parts, namely submucosal injection and perirectal space injection, some authors limited the injection site to submucosal, or to both sides and posterior side of the perirectal space, for the anterior rectum The existing classification and grading criteria for rectal prolapse are not very specific for guiding the treatment of rectal prolapse, because rectal prolapse is often combined with other pelvic floor dysfunctional diseases, such as uterovaginal prolapse, bladder prolapse, constipation and fecal incontinence, etc. Fifth, the mechanism of action of injection therapy for rectal prolapse has not been clarified, so that physicians are not sure about the injection method, injection site, drug concentration and dosage and their relationship with the efficacy, which affects the clinical efficacy and may even lead to some complications; sixth, recurrence, which is the main problem of injection therapy, has been reported. According to our observation, the overall recurrence rate of injection therapy is 16%, which is much higher than this rate, especially for female patients with uterine prolapse; seventh is the post-injection sequelae, such as fecal incontinence, anorectal swelling and pain, constipation, etc. How to solve the above-mentioned problems is to be continued by anorectal medical practitioners. 9.Conclusion Injection therapy for rectal prolapse is less invasive, economical, safe, efficacious, and easy to operate, suitable for hospitals at all levels, easily accepted by patients, and convenient for clinical promotion. In particular, the injection therapy of elimination of hemorrhoids has no serious complications even in large doses, and can be the first choice of treatment for rectal prolapse. The recent efficacy of the injection therapy is certain, and if the problem of recurrence can be solved, the fundamental problem of rectal prolapse treatment will be solved. Therefore, it may be an important direction of rectal prolapse research for a long time in the future to select different treatment methods and develop individualized treatment plans according to the different conditions of patients. Therefore, the research on rectal prolapse has always been a hot issue in anorectal medicine, because the long-term complete rectal prolapse will lead to the risk of anal incontinence, ulceration, bleeding, stricture and necrosis due to nerve damage in the pubic area. The treatment of rectal prolapse is mainly surgical, with more than 100 transabdominal surgical methods and laparoscopic surgery showing its latest progress; there are also dozens of transperineal surgeries, and injection therapy occupies an important position. Each procedure has its own advantages and disadvantages, and selective application of various procedures can greatly improve the outcome compared with a single procedure, and individualized treatment plans may be an important direction for future research. The contents of this paper basically cover the current status of research on injection therapy for rectal prolapse. The systematic study of injection therapy and the comprehensive and objective evaluation of the advantages and disadvantages of each injection therapy, its efficacy and problems are of certain guiding significance for clinical practice. However, the most widely accepted injection therapy is the injection of hemorrhoid elimination, which has positive recent efficacy, but the disadvantage is that there is still a certain recurrence rate. We can select the appropriate injection method according to the different conditions of patients and develop a personalized treatment plan to improve the efficacy and reduce the recurrence rate. Peer evaluation This paper is comprehensive, clear and of good value to clinicians.