Rectal prolapse is the downward displacement of the mucosa or whole layer of the anal canal, rectum, and sigmoid colon. In recent years, it is less common, and the mucous membrane of the rectum is often prolapsed in children, and the whole layer of the rectum and sigmoid colon is mostly prolapsed in adults.
I. Etiology
The etiology of rectal prolapse is not fully understood, and is considered to be related to a variety of factors.
1. Anatomical factors
(1) the small curvature of the sacrococcygeal bone in children, the rectum vertically withstand intra-abdominal pressure, when the abdominal pressure increases, easy to form rectal prolapse.
(2) weak pelvic floor tissues and anal sphincter, female pregnancy and childbirth to pelvic floor tissue damage, elderly muscle relaxation, pediatric dysplasia, trauma, surgery injury to the pubic nerve or perianal sphincter.
(3) Long-term intra-abdominal pressure increase Constipation, diarrhea, chronic cough, prostate hypertrophy, urinary retention.
2.Pathological anatomical features
(1) Deepening of the Douglao depression.
(2) Separation of rectum and sacrum in a vertical position.
(3) The sigmoid colon is redundant.
(4) Separation of the anal levator muscle and relaxation of the anal sphincter.
Pathogenesis
1. Sliding hernia theory In 1912, Moschcowitz proposed that rectal prolapse is a sliding hernia formed by the protruding part of the rectum through the pelvic floor defect. Due to the pelvic floor defect, the rectal bladder sink or rectal uterine sink is too deep, and the increased intra-abdominal pressure presses the anterior wall of the rectum into the rectal jugular and gradually prolapses out of the anus.
2, the theory of intestinal pile-up In the larger abdominal pressure, the first loop pile-up is formed at the junction of the rectum and gradually deepens until it comes out of the anus. This process can be confirmed by defecography.
III. Classification
Mucosal prolapse of the rectum is called incomplete prolapse, and prolapse of the whole rectal wall is called complete prolapse. If the prolapsed rectal wall is inside the anus, it is called internal prolapse, and if it is outside the anus, it is called external prolapse. Rectal prolapse generally refers to the external prolapse of the rectum, and in 1975, the China Anal Academic Conference divided rectal prolapse into three degrees; Ⅰ degree prolapse: prolapse of the rectal mucosa when defecating or increasing abdominal pressure, with a length of less than 4 cm, which can be reset by itself after defecation. Ⅱ degree prolapse: the whole rectum prolapses when defecating, with a length of 4-8 cm, and must be reset by hand. Ⅲ degree prolapse: the anal canal, rectum and sigmoid colon prolapse more than 8 cm when defecating, which is difficult to reset.
IV. Diagnosis and differential diagnosis
Patients squatting to do defecation, prolapse can be gradually prolapse with the increase of abdominal pressure, complete rectal prolapse, prolapse spherical or inverted pagoda-like, the surface can be seen in the circumferential rectal mucosal folds. The tough and elastic rectal wall can be palpated by finger palpation. Rectal mucosal prolapse, a circular uniform mucosal prolapse with a soft texture. The mucosal prolapse of circumferential internal hemorrhoids is clearly visible as a mass of hemorrhoids in a lobulated shape, with normal mucosal depressions visible between the hemorrhoid blocks. Anal palpation: The anal sphincter is relaxed in patients with rectal prolapse, while the anal sphincter is strongly contracted in patients with circumferential internal hemorrhoids. After some surgeries, which cause anal defect, resulting in prolapse of rectal mucosa, such as after hemorrhoid circumcision, and after anal fistula, the mucosa is prolapsed in blocks or rings near the scar identification is not difficult yet.
V. Treatment
The treatment of rectal prolapse is considered from several aspects: fixation of prolapsed rectal mucosa and rectum with surrounding tissues, narrowing of rectum and anal canal, removal of prolapsed intestine to remove the source of prolapse, repair and fixation of pelvic floor tissues.
1.Transanal canal treatment
(1) Injection therapy The therapy is divided into submucosal rectal injection method and perirectal injection method. The therapy is to inject sclerosing agent into the submucosa, posterior rectal space, pelvic rectal space to produce a sterile inflammatory response, so that the rectal mucosa and muscle layer, rectum and surrounding tissue fixed. Operation essentials: the drug should be used to sclerosing agent, subrectal mucosal injection: needle from the dentate line, located at the truncated position 3.6.9, needle at the dentate line, the operator is guided in the anus to perform subrectal mucosal layer columnar injection, not injected into the muscle layer. Perirectal injection method: the puncture point is taken at the truncated position 3.6.9, 1.5-2.0 cm from the anal verge, the index finger of the left hand is guided in the anus, through the skin, subcutaneous, into the sciatic rectal fossa, break through the resistance of the anal levator muscle, into the pelvic rectal gap, the posterior side into the posterior rectal gap, the needle tip can slide freely outside the intestinal wall to inject 5-7 ml of the drug, after treatment, attention should be paid to the control of defecation.
(2) rectal mucosal columnar resection suture: saddle anesthesia or sacral anesthesia, stone position 3.7.11 points, Alis traction on the dentate line, 18 cm vascular forceps longitudinal clamp rectal mucosa 4-6 cm, resection of mucosa on the clamp, continuous suture from the proximal rectum to the dentate line. After surgery, three columns of mucosa are formed and fixed with the base, which is more reliable than injection therapy.
Transanal canal therapy is currently an important means of treating Ⅰ-Ⅱ rectal prolapse, mainly for pediatric patients, and can still be given to patients who cannot tolerate surgery or are unwilling to undergo surgery, with the disadvantage of higher injection drug and operation technique and high recurrence rate. Acute and chronic proctitis and diarrhea patients are prohibited. In China, there is a combination of sclerotherapy and anal canal tightening, the efficacy is better.
2. Transabdominal surgery
(1) transabdominal rectal suspension and fixation currently long with: transabdominal prerectal suspension and fixation (Ripstein surgery): the surgical method is to use mesh band or other materials around the rectum, fixed in the presacral fascia or periosteum, and suture with the anterior rectal wall, so as to straighten and fix the rectum and avoid vertical rectal pressure, the operation does not need to remove the intestinal canal, pay attention to the mesh band wrapped around the front wall to leave a gap, to prevent too tight. The procedure does not require resection of the intestinal canal. Intraoperative fixation should not damage the anterior sacral plexus. Teflon, Marlex and absorbable mesh belts are commonly used, and it has been reported that Marlex mesh belts can reduce the probability of local infection. Ivalon implantation stiffens the rectum and induces aseptic inflammatory fibrosis, which effectively prevents the formation of rectal condyloma and rectal prolapse.
In transabdominal rectal suspension and fixation surgery, due to the inflammatory effect of the implant material, the rectal wall stiffens and hardens, and the rectal function decreases significantly, and constipation and defecation difficulties and rectal stricture often occur. Strict aseptic operation and hemostasis during surgery, pelvic septic infection of the implant material will become very difficult to deal with.
(2) anterior rectal wall folding (Shen Kefei surgery) through the anterior rectal wall multi-layer (generally 3~5 layers) folding to make the anterior rectal wall shorten, harden, and make the muscle layer with mucosa and surrounding tissues fixed to treat rectal prolapse, the freeing of the anterior rectal wall should be adequate, folding should be from telemetry to proximal measurement, now this surgery is used to the freeing of the posterior rectal space should also be adequate, while rectosacral fixation, raising the trap Douglas, reconstruction of pelvic floor muscles and other treatments.
(3) Anterior rectotomy is a more common surgical procedure for the treatment of rectal prolapse. The surgery removes the long prolapsed sigmoid colon and the upper rectum, eliminates the prolapsed source bowel section, and the surgical efficacy is certain. The surgical anastomosis should pay attention to the size of the intestinal caliber and the inconsistent thickness of the intestinal wall in the proximal and distal measured sections to prevent anastomotic leakage. In the case of thickening of the distal rectal intestinal wall attention should be paid to the length of the stapled leg of the closure device, the closure often fails and should not be applied reluctantly, manual anastomosis is more reliable. The anastomosis should be as low as possible, with a high anastomotic position, the retained distal rectal mucosa may still be prolapsed. Due to the damage and relaxation of the anal sphincter caused by long-term prolapse, as well as the inflammatory stimulating effect of the anastomosis, most patients have more frequent defecation and less control, so anal tightening is feasible. However, the treatment effect is better for patients with rectal prolapse accompanied by constipation.
(4) Rectal resection and pull-out anastomosis The long prolapsed sigmoid colon and upper rectum were removed, the intestinal canal was severed in the abdominal cavity, and the distal end of the rectum was pulled out of the anus with an oval forceps after rinsing and dilation, and an incision was made at the tooth line of the anterior rectal wall, and the proximal end of the rectum was pulled out with an oval forceps and anastomosed while cutting, and the anastomosis was sent into the anus. The anastomosis position of the anastomosis is more than that of the anterior resection, the prolapsed rectum and mucosa are more completely resected, and the possibility of mucosa re-prolapse is less. Due to the hyperplasia and hypertrophy of the rectal wall in patients with long-term prolapse, the proximal intestinal canal is of small caliber and the distal intestinal canal is of large caliber after intestinal dissection, and the intra-abdominal double anastomosis with ultra-low anastomosis cannot be performed. We used this procedure to treat several patients with III degree rectal prolapse with satisfactory results.
(5) Total pelvic patch repair is suitable for elderly patients with pelvic multi-vessel prolapse, and a patch is implanted between the sacrum and perineum to the pubic bone via abdominal or perineal surgery to support the rectum, vagina and bladder. It can treat rectal prolapse, vaginal uterine prolapse and bladder prolapse at the same time. The surgical result is good but the rate of complications caused by the patch is high.
3. Trans-perineal surgery
(1) Trans-perineal rectosigmoid partial resection The prolapsed long intestinal wall tube anastomosis is removed in one stage through the perineum. It is mainly suitable for elderly and frail patients with long prolapsed intestinal segments or patients with prolapsed intussusception who are not suitable for transabdominal surgery. For patients with repositionable rectal prolapse, this procedure should be applied with caution, because the rectum forms a certain sequence in the process of prolapse, and it is almost impossible for the operator to pull out the patient after anesthesia, or to pull out the maximum length of prolapse at the time of prolapse, which may often result in incomplete resection. Or the intestinal canal may not be pulled out at all after anesthesia making the procedure impossible. The risk control of this procedure should pay attention to: the presence of small intestine and other abdominal contents herniated at the same time during the process of detachment; the anastomosis is performed under suture while cutting, the abdominal side is not under direct vision, the treatment of the mesenteric vessels should be careful and reliable, and the hemostasis of the anastomosis should be complete.
(2) Anal canal tightening A silicone band or silver or chromium wire is implanted subcutaneously around the anus to tighten the anus and removed after 12 weeks. The operation can be completed under local anesthesia, and the operation is simple. It can be used as an adjuvant treatment for those who are too old and weak to tolerate other operations, but the treatment is unsatisfactory and the recurrence rate is high because it cannot remove many causes of rectal prolapse. In China, the patient’s own anal sphincter or pectineal belt tightening is commonly used for treatment, avoiding complications such as infection and skin ulceration caused by the implantation of foreign bodies.
4, laparoscopic surgery for rectal prolapse With the gradual development of laparoscopic colorectal surgery in China’s anorectal surgery, this surgical method will replace the traditional into the abdomen conventional surgical methods, the current national development is still small. There are more reports of laparoscopic surgery for rectal prolapse abroad, including anterior rectal resection, rectal fixation, rectal suspension and pelvic floor patch implantation. There is no significant difference between the results of laparoscopic surgery and conventional caesarean surgery. The advantages of laparoscopic surgery are ease of operation, minimal invasiveness, low intraoperative bleeding, rapid postoperative recovery, small scar, aesthetics, short hospital stay and few complications. The disadvantages are mainly that the surgical results are affected by the level of technology, and it represents the development direction of surgical treatment of rectal prolapse.