Pelvic floor syndrome

　　1. Causes of Disease

　　Abnormalities in pelvic floor function are caused by neurological and/or muscular abnormalities. In pathological conditions, there may be dysfunction in fecal continence and/or defecation, leading to symptoms such as difficulty in defecation or fecal incontinence. The level of the lesion in patients may not be consistent and may be located in the pelvic floor or in the central nervous system. Some may have local anatomical abnormalities, such as rectal prolapse; some patients may alternate between difficulty in defecation and fecal incontinence at different stages. However, their common point is the dysfunction of the anal-rectal pelvic floor. Common causes are as follows:

　　1. Outlet Obstructed Constipation: This group of patients presents with extremely difficult passage of feces through the anal canal, with great effort in defecation. The etiology and mechanism are not very clear, and it may be a group of multifactorial dysfunction.

　　(1) Anal Spasm: The difficulty in defecating in this group of patients is due to the inability of the pelvic floor striated muscles, mainly the puborectalis muscle and the external anal sphincter, to relax. Sometimes the activity of the puborectalis muscle is反而 enhanced during defecation, losing coordination of movement, leading to incomplete perineal descent, causing difficulty defecating, incomplete defecation, and anal pain. Patients often abuse lubricants, enemas, and have fecal leakage and rectal pain.

　　(2) Adult Megacolon: Caused by the lack of certain ganglion cells at the anal-rectal junction, it is difficult to initiate defecation as feces reach the rectum, making it difficult to identify clinically.

　　(3) Impaired Anorectal Sensation: Due to long-term excessive force during defecation, the perineal nerve (which支配s the external anal sphincter, urinary sphincter, and puborectalis muscle) is damaged, causing delayed defecation sensation when the rectum is filled and expanded, with increased sensory threshold, and often accompanied by a reaction disorder of the external anal sphincter and puborectalis muscle to the filling and expansion of the rectum, causing difficulty defecating. Some are accompanied by fecal incontinence.

　　(4) Descending Perineum Syndrome: Caused by weakened pelvic floor muscle strength, possibly due to aging or nerve damage. During childbirth, it is easy to damage the sacral nerve (S3 and S4) that支配s the puborectalis muscle, once the pelvic floor muscle group is weakened, any exertion can cause significant perineal descent, leading to rectal dilation, excessive rectal mucosal prolapse into the rectum, often with difficulty defecating, frequent sensation of defecation, and strong anal resting pressure and narrowing pressure; repeated rapid descent of the pelvic floor pulls on the perineal nerve that支配s the external anal sphincter, leading to progressive nerve damage, and later incontinence of feces may occur.

　　2. Rectocele: Rectocele refers to the herniation of the anterior wall of the rectum into the posterior vaginal wall. It may be asymptomatic, but most patients present with difficulty defecating, and some complain of anal pain, fecal leakage, anal bleeding, and may also have symptoms such as vaginal prolapse and urinary incontinence. Physical examination or defecation radiography may reveal relaxation of the rectovaginal septum, with three types: low, middle, and high. The low position is above the levator ani muscle, originating from trauma during childbirth, mainly characterized by relaxation of the anal sphincter area (if incontinence of feces occurs, anal sphincteroplasty should be performed). The high position is more common in patients with perineal descent, with near-vaginal proximal prolapse, mostly presenting as intestinal prolapse and genital prolapse. The middle position rectocele is the most common, with typical patients needing to push against the vagina during defecation. If there is crumb-like feces, it needs to be picked out with fingers, or defecation radiography shows a segment of rectum that does not empty, or its length exceeds 3cm, etc., which is caused by rectocele.

　　3. Rectal prolapse (rectal prolapse) can manifest as anterior mucosal prolapse. Overexertion can cause rectal intussusception. The top of rectal intussusception or prolapse is tightly wrapped into the pelvic floor and traumatized, causing solitary rectal ulcer syndrome (solitary rectal ulcers). It can cause bleeding, anal pain, defecation disorders, etc. It is very likely that functional outlet obstruction occurs first, followed by secondary rectal prolapse due to excessive straining during defecation. Rectal prolapse and perineal prolapse will repeatedly pull and injure the pudendal nerve, leading to fecal incontinence.

　　4. Chronic Anal Pain Syndrome (chronic anal pain syndromes) mainly includes levator syndrome (levator syndrome), spasmodic anal pain (proctalgia fugax), coccydynia, descending perineum syndrome (descending perineum syndrome, DPS), and chronic idiopathic anal pain. Among them, the cause of spasmodic anal pain is levator and coccygeus muscle spasm, and hereditary anal internal sphincter myopathy may also be related to pain. In addition, sigmoid colon contraction may also play a role. Coccydynia may be functional, and the cause is unclear.

　　1. Levator Syndrome: Levator syndrome (levator syndrome) is related to levator spasm and often has no obvious cause. It manifests as anal and rectal pain, which is usually not severe,呈钝痛或压迫感，and worsens when sitting, disappearing when standing or lying down, hence it often occurs during the day. It can also manifest as a persistent burning sensation, which patients often describe as a feeling of 'sitting on a ball'. The pain can radiate to the buttocks, and anal palpation can trigger pain. Long-distance driving, female childbirth, and urogenital surgery may worsen the pain. Some patients are related to mental tension. Physical examination shows no positive findings, and sometimes the levator muscle may be palpated as tense, even in a cord-like state. It should be noted to exclude other organic causes.

　　Spasmodic anal pain: Spasmodic anal pain (proctalgia fugax), also known as transient anal pain, is a variant of levator syndrome, caused by levator spasm, rectal and anal canal ischemia, or rectal spasm. It may also be related to psychological factors, with a higher incidence among women, most of whom are professional women, often accompanied by excessive anxiety or neurotic tendencies. It manifests as episodic severe pain,呈绞痛、灼痛、刺痛，which can occur after defecation or unpleasant sexual intercourse, especially at night, when the patient may be woken up by the pain. The pain is persistent, non-radiating, lasting from a few seconds to several minutes, and during an attack, rectal palpation can detect levator spasm, or rectoscopy shows spasm at the junction of the rectum and sigmoid colon (difficult to pass through).

　　(3) Coccydynia: Coccydynia is characterized by pain in the lower sacrum, perineum, anal canal, thigh, and coccygeal area, presenting as persistent dull pain, burning sensation, or spasmodic pain, which can be accompanied by tenderness in the sacrococcygeal region and levator ani spasm. It is often triggered by defecation, sitting, coccygeal trauma, and most of the time occurs during the day. Most patients are anxious or depressed, and psychological treatment has a certain effect.

　　(4) Descending perineum syndrome (descending perineum syndrome, DPS): The descending perineum syndrome is a pelvic floor disease caused by various reasons leading to the degeneration and dysfunction of pelvic floor muscles, manifested as the descent of the perineum beyond the normal range when at rest or during defecation. In cases of obesity, advanced age, perineal nerve injury caused by delivery, anal surgery narrowing, etc., the tension of the pelvic floor muscle group decreases. Due to excessive effort during defecation, the rectal mucosa can prolapse, the mucosa of the anterior rectal wall can sink into the anal canal and be difficult to复位, and stimulate the patient to produce a feeling of descent, causing a vicious cycle, making the perineum continue to descend, and forming the descending perineum syndrome. Patients have a feeling of incomplete defecation, anal distension, difficulty in defecation, and perineal pain. When defecating or walking, a mass can prolapse from the anus. Physical examination shows that when the patient performs a simulated defecation action, the perineum appears spherical. Digital rectal examination shows reduced tension of the anal sphincter muscle. If an anal scope examination is performed, the distal end of the anal scope can be blocked by rectal mucosa.

　　(5) Chronic idiopathic anal pain: This condition is more common in women, mainly manifested as a persistent pulsating burning sensation in the middle segment of the anal canal, as if a ball is inside the anal canal, or intermittent, can be unilateral, radiating to the abdomen, thigh, sacrum, and vagina, and can be accompanied by pelvic or spinal surgery, myelography, or perineal descent. It is often induced by sitting, can occur at any time, often in the latter half of the day, and can be relieved when lying down.

　　5. Idiopathic fecal incontinence (idiopathic fecal incontinence) is also known as neurogenic fecal incontinence, whose etiology is the progressive damage to the nerves that支配盆底横纹肌及肛外括约肌 and the decreased function of the internal sphincter muscle. Most patients have a decrease in anal resting pressure and narrowing pressure, abnormal electromyography of the external anal sphincter muscle, indicating that neurological lesions are the underlying cause. Some patients have a significantly increased rectal pressure, exceeding the anal pressure, leading to fecal leakage. Many patients with fecal incontinence have a blunted anal-rectal angle. If there is no significant decrease in anal resting pressure and narrowing pressure, fecal incontinence may not occur; if the anal sphincter function is incomplete, but as long as the anal-rectal angle is still normal, it is usually still possible to control the formation of feces.

　　Second, pathogenesis

　　The anatomical structure of the anorectal region and the pelvic floor is relatively complex, with both striated muscle and smooth muscle parts, mainly including:

　　1. The rectum, levator ani, puborectalis muscle, and the sacral nerves that innervate them.

　　2. The external anal sphincter and perineal nerves.

　　3. The anal internal sphincter (smooth muscle) and endogenous and autonomic nerves, etc. These muscle groups are highly coordinated in defecation control and defecation. The central nervous system, peripheral nervous system, and enteric nervous system participate in the regulation. Gastrointestinal hormones may also play a certain role. Factors related to defecation control and defecation.

　　（1）Factors related to defecation control: The reason why defecation can be controlled is due to the role of the high-pressure zone of the anal canal, the constrictive pressure of the external anal sphincter, and the “valve” role of the anorectal angle. In addition, the compliance of the rectal wall and the anorectal inhibitory reflex also play a regulatory role in defecation control, and the formed feces itself also has a role in defecation control. The factors for defecation control include:

　　①High-pressure zone of the anal canal: About 4cm long, the anal canal is in a high-pressure state at rest, mainly produced by the continuous contraction of the anal internal sphincter. The contraction of the anal internal sphincter prevents the leakage of intestinal contents, and the pressure difference between the high-pressure zone of the anal canal and the intrarectal pressure is an important condition for long-term defecation control.

　　②Constrictive pressure of the external anal sphincter: If defecation cannot be performed immediately, the external anal sphincter and the puborectalis muscle of the pelvic floor contract, producing a constrictive pressure 2-3 times higher than the resting pressure, which strengthens the role of defecation control, but the duration is short, often not exceeding 1 minute. Therefore, if the intrarectal pressure increases significantly, the intestinal contents in the proximal anal canal may leak.

　　③The role of the anorectal angle “valve”: When in a resting left lateral position, this angle is 102°±18°, and when sitting, it is 109°±17°. When the pelvic floor muscle group contracts, the pelvic floor is elevated, and the angle becomes smaller, playing a “valve” role.

　　④Anorectal inhibitory reflex: Normally, when feces enter the rectum, it will cause an anorectal inhibitory reflex, that is, the anal internal sphincter relaxes, and the anal external sphincter contracts. The latter prevents the expulsion of rectal contents and has a role in defecation control. If defecation cannot be performed immediately, the anal internal sphincter will no longer relax.

　　⑤Rectal wall compliance: When the rectal contents increase, the rectum can passively adapt to tension, and the intraluminal pressure remains very low. This rectal wall relaxation can effectively prevent the intraluminal pressure from exceeding the anal pressure, playing a role in defecation control. However, if the rectal contents continue to increase, the intrarectal pressure will increase, and the maximum tolerance capacity is usually 200-300ml.

　　⑥ The role of stool shaping in the colon: It is more difficult to expel formed stools than watery stools, which is also one of the stool control mechanisms. Watery stools can enter the rectum in large quantities, overcoming the stool control mechanism, and are prone to cause incontinence. Under normal circumstances, the above control mechanisms are perfect, and fecal incontinence will not occur.

　　(2) Related factors of defecation: The main related factors for initiating defecation are:

　　① Colonic peristalsis: It can push the intestinal contents to the distal colon. When the contents of the sigmoid colon reach a certain amount, it contracts, and the stool enters the rectum, causing the rectum to dilate and triggering the rectum-anal inhibitory reflex. Due to the relaxation of the internal anal sphincter and local expansion, the rectal contents can enter the proximal part of the anal canal, allowing the local mucosal receptors to perceive the intestinal contents as liquid, solid, or gas. If conditions permit, enter the defecation state.

　　② During defecation, the external and internal anal sphincters and the puborectalis muscle are relaxed, the pelvic floor descends, forming a funnel, the anal-rectal angle becomes larger, and the increased intra-abdominal pressure acts directly on the stool to expel it. The entire left half of the colon contracts to empty the stool. After defecation, the external anal sphincter and the puborectalis muscle alternate in contraction, which is the end reflex. This reflex can promote the tension recovery of the internal anal sphincter and close the anal canal.

　　③ After eating, the rectal volume decreases, while the tension of the rectal wall increases. This reflex is beneficial to rectal emptying.

　　Due to dry and hard stools, the effort and incomplete defecation, long-term straining during defecation often results in bloody stools and mucus, which often indicates rectal prolapse. There may also be related solitary rectal ulcers. Many patients with fecal incontinence have a blunted anal-rectal angle. If there is no significant decrease in the resting pressure and narrowing pressure inside the anus, fecal incontinence may not occur. If there is incomplete function of the anal sphincter muscle, but as long as the anal-rectal angle is still normal, it is usually still possible to control the formation of feces.

　　The most common symptoms include constipation, fecal incontinence, pelvic floor pressure, pain, urgency, difficulty in defecation, and rectal prolapse, among which constipation is the most ambiguous symptom. The defecation frequency of the vast majority of patients is 3 times/d to 3 times/week. If asked carefully, it will suggest difficulty, effort, discomfort, or lack of defecation desire, and inability to initiate defecation.

　　If 1/4 of the time is needed to strain during defecation, it indicates pelvic floor dysfunction, pelvic floor pressure, difficulty or inability to defecate, and a sense of obstruction also suggests pelvic floor dysfunction. Please note that about 50% of normal people occasionally experience incomplete defecation, and 10% may have this symptom frequently. Long-term straining during defecation often results in bloody stools and mucus, which often indicates rectal prolapse. There may also be related solitary rectal ulcers, but it is necessary to exclude the possibility of tumors and inflammatory bowel diseases.

　　50% of patients with fecal incontinence do not actively report this symptom unless asked in detail. These patients have a long history of straining during defecation, and childbirth is an important factor causing pelvic floor injury. To understand the situation of childbirth, perineal incision or laceration, traction technique, prolonged labor, and birth of a macrosomic baby are all important risk factors.

　　Prevent and treat the etiological diseases that cause pelvic floor syndrome. The most prominent advantage of seaweed is its rich abnormal soft fiber, which is a dedicated 'cleaner' in the human intestinal tract, and the coarse fiber in seaweed is difficult to be digested by the human gastrointestinal tract, which can increase peristalsis and smooth defecation after eating. Regularly eating seaweed soup can also clear harmful substances accumulated in the intestinal lumen, maintain intestinal health, and is beneficial for prevention.

　　The use of manometric instruments to measure rectal pressure is helpful for the diagnosis of pelvic floor syndrome, generally including the measurement of anal length, anal resting pressure, rectal narrowing pressure, and defecation pressure, but attention should be paid to the fact that although gastrointestinal pressure measurement is very important for the diagnosis of diseases with esophageal, small intestinal, and Oddi sphincter motility disorders, and adult-type Hirschsprung's disease, in some cases, the results of rectal manometry may have a significant gap from the clinical situation of patients with pelvic floor syndrome, so the results of rectal pressure measurement should be treated with caution.

　　In 85% of patients with anal pain during defecation, transanal ultrasound can detect shortening and thickening of the anal sphincter muscle (the shortening and thickening of the puborectalis muscle is more significant), while the same changes are only seen in 35% of the normal population, and transanal ultrasound examination is of certain significance for the diagnosis of pelvic floor muscle coordination disorders and anal spasm.

　　The application of defecation imaging technology to measure the patient's anal-rectal angle, anal superior distance, intestinal pubic distance, and length and depth of the puborectalis muscle indentation, if the puborectalis muscle does not relax and/or contract during forceful defecation, the anal-rectal angle does not increase or decrease, and the puborectal indentation and indentation deepening and widening can be seen, and when the rectal ampulla is narrow, pelvic floor syndrome can be diagnosed.

　　In addition to routine treatment, attention should be paid to diet for patients with pelvic floor syndrome: it is advisable to eat nutritious, easy-to-digest, and light foods, eat more fruits and vegetables, drink more water. Avoid spicy foods. Avoid greasy and rich foods. Eat light and reduce the intake of spicy and stimulating foods.

　　First, treatment

　　Due to the unclear etiology and pathophysiology of pelvic floor syndrome, there are many shortcomings in the current treatment methods for the disease.

　　1. For patients with constipation caused by obstructive constipation who have experienced unfortunate events, their mental state should be adjusted. Some patients may need to take laxatives. For patients who are ineffective with high-fiber diets, the colonic transit time under a sufficient fiber diet should be re-measured to determine whether the patient is suitable for high-fiber diets.

　　Patients with anal spasm can be treated with Botulinum toxin (Botulinum toxin, Botox) injection, with 10U Botox injected into each side of the puborectalis muscle or 20U Botox injected into the posterior part of each side of the puborectalis muscle, which has a good therapeutic effect on anal spasm, and the side effects and complications of this therapy are relatively few, and there have been no complications found to be life-threatening to patients so far.

　　2. Rectal Prolapse There are many treatment methods for rectal prolapse. Under colonoscopy direct vision, injection needles are used to draw drugs (such as Hemorrhoid Elimination Injection) and inject them into the high rectal mucosa. By causing aseptic inflammation and fibrosis between the rectal mucosa and the muscular layer or the high rectal part and the surrounding tissues, it causes adhesion and fixation between the rectum and the surrounding tissues. In addition, rectal prolapse is one of the indications for surgery. The current surgical methods for rectal prolapse include: rectal scar fixation surgery, intestinal resection, anal sphincter folding surgery, rectal suspension fixation surgery, and anal ring contraction surgery. Each of the above surgical methods has its own advantages and disadvantages, and should be selected according to the patient's clinical condition and the surgeon's technical level. Whether to perform surgical treatment for occult rectal prolapse is still controversial at present. Since biofeedback therapy has good efficacy for some patients, it is better to start with functional exercise first.

　　3. Fecal Incontinence (encopresis) If there is injury to the anal external sphincter causing fecal incontinence during delivery or rectal and anal canal trauma, then the surgery for anal sphincteroplasty and perineal reconstruction often has good efficacy.

　　For neurogenic fecal incontinence caused by congenital spinal cord developmental malformation, bilateral iliac psoas transfer to strengthen the pelvic floor muscle substitute surgery can be adopted. After surgery, combined with coordination and coordination training of the pelvic floor muscle and adjacent muscle, rectal reflex induction training and defecation reflex rehabilitation training can often achieve good efficacy.

　　II. Prognosis

　　Before considering surgery for patients with pelvic floor syndrome, biofeedback therapy should be performed first. This is a training activity that can only be carried out under the detailed guidance of a physiotherapist. By exercising the pelvic floor specifically, it has certain efficacy for constipation and anal pain. For patients who have failed to respond to the above treatment, it is still necessary to be very cautious when selecting elective surgical treatment. Even for patients with constipation who also have severe anal pain, the elimination of pain should not be the ultimate goal of surgical treatment. The efficacy of the current rectal muscle splitting and anal sphincterectomy is not very certain.