Rectal and Anal Canal Diseases
Part I Anatomy of the rectum and anal canal (combined with the wall chart)
The rectum is the end of the large intestine, and the continuation of the colon is similar to the colon, but it is different from the colon because of its anatomical and clinical particularities.
The rectum is connected to the sigmoid colon and the anal canal in the lower part. It is about 12-15cm long. It starts from the third sacral vertebra and descends from the anterior sacrum until the coccyx plane meets the anal canal to form a 90° bend. The upper part of the rectum is the same thickness as the colon, and the lower part expands into the ampulla of the rectum, which is the place where stool is temporarily stored. The upper 1/3 of the rectum is covered with peritoneum on the front and both sides; the middle 1/3 only has the peritoneum on the front and is folded back into a rectal bladder depression or rectal uterine depression; the lower 1/3 is all located outside the peritoneum, so that the rectum is in the abdominal cavity The inside and outside account for half.
The muscular layer of the rectum is the same as the colon and is divided into two layers, the outer longitudinal muscle and the inner circular muscle. The circular muscle layer extends to the lower end of the rectum and thickens, forming the internal anal sphincter. The lower end of the longitudinal muscle layer is connected to the levator ani muscle and the internal and external sphincter, and plays a certain role with the sphincter during defecation. The rectal mucosa is close to the intestinal wall, and there is no spiral fold formed by the colonic mucosa when observed under a rectal microscope, but there are three horizontal half-moon folds in the ampulla of the rectum. Fold.
Because the lower end of the rectum is connected to the smaller anal canal, its mucosa presents 8 to 10 raised longitudinal folds, which are called anal columns. There is a half-moon fold between the bases of two adjacent anal columns, called anal flaps. The rectal mucosa between the anal flap and the anal column forms many pockets called anal sinuses (or crypts). The ostium of the anal sinus is upward, 3～5mm deep, and there is an anal gland opening at the bottom.
Due to the anatomical characteristics here, it is vulnerable to injury and infection. At the point where the anal canal connects with the anal column, there is a triangular papillary bulge called anal papilla. These anatomical structures form an irregular line at the junction of the rectum and anal canal, called the dentate line.
Anatomy does not have the term mesorectum. The mesorectum in surgery refers to the connective tissue that surrounds the rectum at the back and on both sides of the middle and lower rectum and forms a semicircle of 1.5 to 2.0 cm. It contains arteries, veins, and lymph. The tissue and a large amount of adipose tissue go up from the front of the 3rd sacral vertebra and down to the pelvic diaphragm.
The anal cushion is located at the junction of the rectum and anal canal, also known as the rectal anal canal transition area (hemorrhoid area). This area is a circular, about 1.5 cm wide, spongy tissue belt, rich in fibrous muscle tissue (Treitz muscle) mixed with blood vessels, connective tissue, elastic tissue and smooth muscle fibers. Treitz wraps around the rectal venous plexus in a network-like structure to form a supportive frame that fixes the anal cushion to the internal sphincter. The anal cushion is like a rubber cushion to help the sphincter to close the anus.
The anal canal is the end of the digestive tract, from the dentate line up to the anal margin, about 1.5 to 2 cm long. The inner layer of the anal canal is the upper part of the transitional epithelium, and the lower part is the squamous epithelium. The anal canal is surrounded by internal and external sphincter muscles.
Internal anal sphincter
The internal anal sphincter is an involuntary muscle, which is actually an extended and thickened circular muscle at the lower end of the rectum, surrounding the upper 2/3 of the anal canal.
The external anal sphincter is a voluntary muscle, which is penetrated by the longitudinal rectal muscle and levator ani muscle fibers and divided into three parts: subcutaneous, superficial and deep parts.
The lower part of the skin is a circular muscle bundle, located in the subcutaneous layer of the lower end of the anal canal, below the internal anal sphincter; during digital rectal examination, it can be palpated that there is a circular shallow groove between the internal anal sphincter and the external anal sphincter, called The white line is equivalent to the boundary line of the lower 1/3 of the anal canal.
The superficial part is an elliptical muscle bundle, which starts from the tailbone and divides forward into two bundles, surrounding the anal canal and ending at the perineum; the part connected with the coccyx forms a strong ligament, called the anal-caudal ligament.
The deep part is located on the outer and upper part of the superficial part is the circular muscle bundle, and the back part merges with the puborectal muscle fibers.
Because the deep part of the external anal sphincter, the puborectalis muscle, the internal anal sphincter and the longitudinal rectal muscle fibers form a muscle ring, it can be clearly seen during digital rectal examination, called anorectal ring.
The external anal sphincter is composed of three muscle loops: the deep part is the upper ring, which merges with the puborectalis muscle and is attached to the pubic symphysis. It is lifted forward and upward during contraction; the superficial part is the middle ring, which is connected to the tailbone, and is simultaneously backward during contraction. Stretching; the lower part of the skin is the lower ring, which is connected to the subcutaneous front of the anus, and simultaneously pulls forward and downward when contracting. When the sphincter is contracted, the three rings are pulled in different directions while contracting to strengthen the function of the anal sphincter.
When the external anal sphincter contracts, the upper and lower rings pull the back wall of the anal canal forward, and the middle ring pulls the anterior wall of the anal canal backwards to close the anal canal; the three rings can repeatedly peristalize and contract to discharge the remaining in the anal canal stool. Among the three rings, the upper ring is the most important and can cause incontinence after being cut off; the lower ring has weaker function, so cutting does not cause incontinence.
The levator ani is a wide and thin muscle that forms the pelvic floor around the rectum. It consists of three parts: the puborectalis, pubococcygeus and iliac coccyx muscles, one on each side, and the puborectalis muscle part merges with the back of the external anal sphincter. , A total of the anal sphincter function.
On the levator ani muscles are: ①The pelvic rectal space, one on each side of the rectum, above the levator ani muscle, and below the pelvic peritoneum; ②The posterior rectal space, between the rectum and the sacrum, and also the levator ani muscle Above, it can communicate with the pelvic and rectal space on both sides.
Below the levator ani muscle: ①The ischial anal gap (also known as the ischiorectal gap), on both sides of the anal canal, located under the levator ani muscle, above the diaphragm of the ischial anal canal, one on each side, after passing through the anal canal Connected (here also called the deep posterior anal space). ②The space around the anus is located between the diaphragm of the ischial anal canal and the skin around the anus. The left and right sides are also connected behind the anal canal (here also called the superficial retroanal space).
Supply arteries of rectal anal canal
The supply arteries of the rectum and anal canal come from the superior rectal artery, inferior rectal artery, anal artery and middle sacral artery.
The superior rectal artery is the most important branch of the rectal supply artery. It comes from the inferior mesenteric artery and is divided into two branches on the upper back of the rectum. It descends along both sides of the rectum, penetrates the muscle layer and reaches the submucosa above the dentinal line. It is the main supply vessel for internal hemorrhoids. Its branches are located on the left, right front and right back. Therefore, these three places are the most common sites for hemorrhoids. Digital rectal examination can often touch the pulsation of the arterial branches at these sites, and they are also the main sites for injection of sclerosing agents to treat hemorrhoids.
The inferior rectal artery separates from the anterior trunk of the internal iliac arteries on both sides, and reaches the lower rectum through the pelvic rectal space. It is the main supply artery of the lower rectum and is anastomosed with the superior rectal artery on the dentinal line. The anal artery comes from the internal pudendal artery, supplies the anal canal through the ischial anal space, and is anastomosed with the upper and lower rectal arteries. The middle sacral artery is a small branch directly branched from the aorta. It runs down the sacrum and supplies the posterior wall of the lower end of the rectum. It is not important in the blood supply of the rectum.
The venous superior rectal venous plexus of the rectal anal canal is located in the submucosal layer above the dentinal line. It converges into several small veins, passes through the muscularis of the rectum to become the superior rectal vein, and returns to the portal vein through the inferior mesenteric vein. The inferior rectal venous plexus is located below the dentinal line and gathers the anal canal and its surrounding veins. The anal vein and the inferior rectal vein are formed outside the anal canal and the inferior rectal vein, which returns to the inferior vena cava through the internal pudendal vein and the internal iliac vein, respectively.
Lymphatic drainage of the rectum and anal canal
Upper, middle and lower three groups:
The upper group drains the part above the rectum (ampullary and above) of the attachment of the puborectalis muscle. Most of them go through the pararectal lymph nodes, and some of them are directly along the superior rectal artery and injected into the lymph nodes at the beginning of the superior rectal artery in the mesentery. This is the main way of rectal cancer metastasis.
The middle group drained from the lower edge of the upper group to the dentate line, and most of them were injected into the lymph nodes at the beginning of the inferior rectal artery through the levator ani muscle along the inferior rectal artery.
The lower group of drainage is below the anal canal, mainly subcutaneously injected into the superficial inguinal lymph nodes through the perineum and inner thigh, and then upward through the extrailiac and parailiac lymph nodes; there are also parailiac lymph nodes through the obturator artery.
Nerves of the rectal anal canal
The anal canal is mainly innervated by the subrectal nerve and the presphincter nerve, the branches of the pudendal nerve, as well as the coccygeal nerve and the perineal branch of the fourth sacral nerve.
The rectal nerve has sympathetic and parasympathetic nerves. The sympathetic nerve mainly comes from the presacral (lower abdominal) nerve plexus. This plexus is below the aorta and is divided into left and right branches outside the fascia propria of the rectum, each of which converges downwards with the parasympathetic nerve of the sacrum, forming a pelvic nerve plexus on both sides of the lateral rectal ligament. Presacral nerve injury causes the seminal vesicles and prostate to lose contraction and cannot ejaculate. The sacral parasympathetic nerve is branched from the 2nd to 4th sacral nerves and is the main nerve that innervates urination and erection of the penis. It should be injured in a hurry during surgery.
①The above is the mucosa, and the following is the skin; ②The above is the superior rectal venous plexus, and below the dentate line is the inferior rectal venous plexus, so near the dentate line is the anastomosis of the portal and systemic veins; ③The above is the superior and inferior rectal artery Supply, the following is an anal artery supply; ④The above lymphatic drainage mainly enters the abdominal aorta or intrailiac lymph nodes, and the following lymph node drainage mainly enters the inguinal lymph nodes and extrailiac lymph nodes; ⑤The above rectal mucosa is innervated by the autonomic nervous system and is painless. The skin of the anal canal below the dentate line is innervated by the internal pudendal nerves, and the pain is obvious.
Physiological function of rectal anal canal
Mainly bowel movements. The cecum can absorb a small amount of water, salt, glucose and some drugs, and it can also secrete mucus to facilitate bowel movements. Under normal circumstances, stool is stored in the sigmoid colon. When there is no defecation, there is basically no stool in the rectum and the anal canal is closed. The colon moves, the stool descends into the rectum, and the rectal ampulla swells, causing stool and internal anal sphincter reflex relaxation. At the same time, the body autonomously relaxes the external anal sphincter and increases abdominal pressure to excrete stool.
The lower part of the rectum is the main site of defecation reflex, which is an important part of defecation function; if the rectum is completely removed, even if the sphincter is retained, due to the loss of the defecation reflex site, fecal incontinence may still occur. Only by keeping at least 5cm of the rectum connected to the anal canal can normal bowel function be maintained.
The second part of the anal canal inspection method (combined with multimedia)
Check body position
The patient lies on the left side, with his left lower limb slightly bent, and some lower limbs are close to the abdomen.
The patient kneels on the examination table, the head, neck and front chest are cushioned, the forearms are flexed on the chest, and the buttocks are raised. This is the most common position for examining the rectum and anal canal. Anal speculum and rigid sigmoidoscopy are easy to insert, and it is also the prostate. Regular posture for massage.
The patient lies supine on a special examination table, with both lower limbs raised and abducted, hip flexion and knee flexion. This is a common posture for rectal and anal surgery, and this posture is also selected when a bipartite consultation is required.
Take down the posture of squatting and defecation to check internal hemorrhoids, prolapse and rectal polyps, etc. When squatting, the rectum and anal canal bear the greatest pressure, which can lower the rectum by 1~2cm, so the most serious cases of internal hemorrhoids and prolapse can be seen.
Stand with your lower limbs slightly apart, lean forward, and hold your hands on the support. This method is the most common position for anal inspection.
Digital rectal examination
1. Fully lubricate, check the perianal area first.
2. Test the tightness of the anal sphincter and touch the anorectal ring.
3. Check the anorectal wall for tenderness, fluctuations, lumps and stenosis.
4. Normal men can reach the prostate and women can reach the cervix.
5. Check double diagnosis when necessary.
6. Take out the finger cot and observe whether there is blood or mucus. Check the sigmoidoscopy if necessary.
Film degree exam
1. Line inspection
2. Intracavitary ultrasound examination
3. CT examination
4. MRI examination
Rectal and anal canal function test
1. Rectal pressure measurement
2. Balloon expulsion test
3. Anorectal EMG Part 5: Ulcerative Colitis
Part Three Anal Fissure (combined with multimedia)
Anal fissure is a small ulcer formed after laceration of the skin layer of the anal canal below the dentate line. The direction is parallel to the longitudinal axis of the anal canal, about 0.5 to 1.0 cm long, fusiform or elliptical, often causing severe perianal pain. It is more common in young and middle-aged people. The vast majority of anal fissures are located on the posterior midline of the anal canal, and can also be located on the anterior midline. The side is very rare, if there is an intestinal inflammatory disease or tumor.
The cause of anal fissure is unclear, and it may be related to many factors. Long-term constipation and mechanical trauma during defecation caused by dry stool are the direct cause of most anal fissures. The superficial part of the external anal sphincter forms the anal caudal ligament behind the anal canal. It has poor flexibility and rigidity. The blood supply in this area is also poor. The anal canal and the rectum continue at an angle. During defecation, the posterior wall of the anal canal bears the greatest pressure, so the posterior midline Vulnerable to damage.
Acute anal fissures have neat edges, shallow bottom, red and elastic, and no scar formation. Chronic anal fissures have recurring attacks, with irregular bottom depth, hard texture, thickened edges, fibrosis, and pale granulation. The anal flap and anal papilla at the upper end of the cleft are edema, forming hypertrophic nipple; the lower skin is blocked due to inflammation, edema and venous and lymphatic drainage, forming a bag-like skin hanging down and protruding outside the anus, called "sentinel hemorrhoids." Because of anal fissure, "sentinel hemorrhoids", and nipple hypertrophy often coexist, it is called "anal fissure triad".
Patients with anal fissure have typical clinical manifestations, namely pain, constipation and bleeding.
The pain is severe and has a typical periodicity: during defecation, the nerve endings in the anal fissure are stimulated, and anal burning or knife-like pain is immediately felt, which is called pain during defecation; it can be relieved after a few minutes, called intermittent period; Later, due to the contraction and spasm of the anal sphincter, severe pain again, this period can last for half to several hours, clinically called sphincter contracture pain. The pain relieved until the sphincter muscle was fatigued and relaxed, but pain occurred again when defecation again. The above is called anal fissure pain cycle.
Constipation Unwilling to defecate because of fear of pain. Over time, it will cause constipation. The stool will become harder and dry. Constipation will aggravate anal fissures, forming a vicious circle.
Blood in the stool When defecation, a small amount of blood is often seen on the surface of the stool or on the toilet paper, or drips of blood, heavy bleeding is rare.
Diagnosis and differential diagnosis
Based on the typical clinical history and the "triad of anal fissures" found during anal examination, it is not difficult to make a diagnosis. It should be distinguished from anal ulcers caused by other diseases, such as crohn disease, ulcerative colitis, tuberculosis, perianal tumors, syphilis, chancroid and other perianal ulcers.
The treatment of acute or initial anal fissures can be treated by sitz bathing and moisturizing the stool; chronic anal fissures can be treated by sitz bathing, moisturizing the stool to expand the anus; prolonged anal fissures, conservative treatments ineffective, and severe symptoms can be treated with surgery .
1. Non-surgical treatment
The principle is to relieve sphincter spasm, relieve pain, help defecation, interrupt the vicious circle, and promote local healing. ①Sit bath with 1:5000 potassium permanganate warm water after defecation to keep the area clean. ②Oral laxatives or paraffin oil can make the stool soft and smooth; increase drinking water and multi-fiber food to correct constipation and keep the stool smooth. ③Anus expansion: After local anesthesia for the anal fissure, the patient is lying on his side. After expanding the anus with the index finger, gradually extend the two middle fingers and maintain the expansion for 5 minutes. After expansion, sphincter spasm can be relieved, wound surface can be enlarged, and crack healing can be promoted. However, this method has a high recurrence rate, and can cause blood, perianal abscess, and fecal incontinence.
2. Surgical therapy
(1) Anal fissure resection
That is, all the proliferating fissures, "sentinel hemorrhoids", hypertrophic anal papillae, inflamed crypts and deep unhealthy tissues are removed until the anal sphincter is exposed, and part of the external sphincter skin or internal sphincter can be cut off at the same time, and the wound is open and drained. The disadvantage is slower healing.
(2) Internal anal sphincterotomy
The internal sphincter of the anal canal is a circular involuntary muscle. Its spasm and contraction are the main cause of pain in anal fissure. The surgical method is to make a small incision on one side of the anal canal from the anal margin 1 to 1.5 cm to reach the lower edge of the internal sphincter. After determining the intersphincter groove, the internal sphincter is separated to the dentate line, the internal sphincter is cut, and then expanded to 4 fingers, electrocautery or After compression to stop the bleeding, the incision can be sutured, and the enlarged nipples and sentinel hemorrhoids can be removed together, and the anal fissure will heal by itself in a few weeks. This method has a high cure rate, but improper surgery can cause anal incontinence.
The fourth part of the rectal anal abscess (combined with multimedia)
Perirectal abscess refers to an acute purulent infection that occurs in or around the soft tissues around the rectal and anal canal and forms an abscess. Anal fistula is often formed after abscess rupture or incision. Abscess is the acute stage of inflammation around the anorectum, while anal fistula is the chronic stage.
Etiology and pathology
The vast majority of perirectal abscesses are caused by anal gland infection. The opening of the anal glands is in the anal sinus and is mostly located between the internal and external sphincter. Because the opening of the anal sinus is upward, diarrhea and constipation can easily lead to anal sinusitis. After the infection extends to the anal gland, the intersphincter infection is likely to occur first. The space around the rectum and anal canal is loose fatty connective tissue, and the infection can easily spread and spread.
Perirectal abscess can also be secondary to perianal skin infection, injury, anal fissure, internal hemorrhoids, drug injection, sacrococcygeal osteomyelitis and so on. Patients with crohn's disease, ulcerative colitis and hematological diseases are prone to perirectal abscesses.
Taking the levator ani muscle as the boundary, the perirectal abscess can be divided into lower levator ani muscle abscess and upper levator anus abscess: the former includes perianal abscess, ischiorectal space abscess; the latter includes pelvic rectal space abscess, posterior rectal space abscess, High intermuscular abscess.
1. Perianal abscess: Subcutaneous abscess around the anus is the most common, mostly caused by anal gland infection spreading out through the underside of the external sphincter skin. It is often located behind the anus or under the lateral skin, usually not large. The main symptoms are persistent perianal throbbing pain, inconvenience, restlessness, and systemic infectious symptoms are not obvious. The lesion is obviously red and swollen, with induration and tenderness. Abscess formation may be fluctuating, and pus is drawn out during puncture.
2 ischial anal interstitial abscess: also known as ischial rectal fossa abscess, also more common. Mostly formed by the spread of anal gland infection through the external sphincter to the ischi-rectal space. It can also be caused by the spread of an abscess around the rectum. Due to the large space between the ischi and rectum, the abscess formed is also large and deep, with a volume of about 60-90 ml. At the time of the onset, persistent pain on the affected side occurred and gradually worsened, followed by persistent throbbing pain, restlessness, increased pain during defecation or walking, dysuria and tenesmus; obvious symptoms of systemic infection, such as headache, fatigue, fever, loss of appetite . nausea. Chills and so on. In the early stage, the local physical signs are not obvious. Later, the affected side of the anus will be red and swollen, and the hips will be asymmetrical; there will be deep tenderness or even fluctuating feeling on the affected side during local palpation or digital anal examination. If it is not cut in time, the abscess often penetrates down into the space around the anal canal and then penetrates through the skin to form an anal fistula.
3. Pelvic rectal space abscess: also known as pelvic rectal fossa abscess. It is mostly caused by anal gland abscess or ischiorectal abscess piercing the levator ani muscle into the pelvic rectal space. It can also be caused by proctitis, rectal ulcer and rectal trauma. Because this gap is deeper and has a larger space, the systemic symptoms caused by it are heavier but the local symptoms are not obvious. There are symptoms of systemic poisoning in the early stage, such as fever, chills, and general fatigue. The local manifestation is a feeling of rectal swelling and inexhaustible defecation, especially discomfort during defecation, often accompanied by dysuria. The examination of the perineum is mostly normal, and the digital rectal examination can touch the lumps and bulges on the rectal wall, with tenderness and fluctuation. Diagnosis is mainly based on puncture and extraction of pus, positioning with fingers through the rectum, and inserting a needle from the skin around the anus. If necessary, make anal canal ultrasound or CT examination to confirm.
4. Others: there are anal sphincter interstitial abscess, posterior rectal interstitial abscess, high intermuscular abscess. An abscess in the rectal wall (submucosal abscess). Due to the deep location, most of the local symptoms are not obvious, mainly manifested as perineum and rectal swelling feeling, and increased pain during defecation; patients also have different degrees of systemic infection symptoms. Painful mass on digital rectal examination
1. Non-surgical treatment: ① Antibiotic treatment: 2 to 3 kinds of antibiotics that are effective against Gram-negative bacilli can be combined. ②Side bath with warm water. ③ Local physical therapy. ④Oral laxatives or paraffin oil to relieve pain during defecation.
2. Surgical treatment: Incision and drainage of abscess is the main method to treat abscess around rectum and anal canal. Once the diagnosis is clear, incision and drainage should be done. The operation method varies with the location of the abscess.
Abscess around the anus can be performed under local anesthesia. Make a cross-shaped incision at the most obvious part of the fluctuation, and cut off the surrounding skin to make the incision oval without packing to ensure smooth drainage.
Interstitial abscess of the ischial anal canal should be performed under spinal anesthesia or sacral anesthesia. First, puncture the place with obvious tenderness with a thick needle. After extracting the pus, make an arc-shaped incision parallel to the anal margin at the place. The incision should be sufficient Long, the abscess cavity can be explored with fingers. The incision should be 3 to 5 cm away from the anal margin to avoid damage to the sphincter. Tubes or oil gauze strips should be placed for drainage.
Pelvic and rectal space abscess should be performed under spinal or general anesthesia. The incision site is different due to the source of the abscess: ①The abscess originating from the intersphincter should be incised and drained in the corresponding part of the rectal wall under anoscope. Suture to stop bleeding; if drainage through the ischi-rectal space, anal sphincter external fistula is likely to occur in the future ②It originates from an abscess in the ischi-rectal space, and the drainage method is the same as that of the ischi-rectal space. If it is incised and drained through the rectal wall, it is easy to cause difficult to treat Suprasphincter fistula in the anal canal. .
For abscesses in other parts, if the location is low, cut and drain directly on the perianal skin; if the location is high, the rectal wall should be cut and drained under anoscope.
Part 5 Rectal prolapse (combined with multimedia)
Part or all of the rectal wall shifts downward, which is called rectal prolapse. Part of the rectal wall moves down, that is, the rectal mucosa moves down, which is called mucosal prolapse or incomplete prolapse; the full-thickness of the rectal wall moves down is called complete prolapse. If the rectal wall that moves downward is called internal prolapse in the anorectal cavity, it is called external prolapse when it moves downward and out of the anus.
Etiology and pathology: The etiology is unknown and related to many factors.
1 Anatomical factors: infants with dysplasia, malnutrition, elderly and infirm, prone to weakness and weakness of the levator ani muscle and pelvic floor fascia; small curvature and over-straight sacrum in children; surgery, traumatic injury to the surrounding anorectal muscles or nerves, etc. All factors can weaken the fixation and support of the tissues around the rectum to the rectum, and the rectum is easy to prolapse.
2 Increased negative pressure: such as constipation, diarrhea, enlarged prostate, chronic cough, dysuria, multiple childbirth, etc., often increase abdominal pressure and push the rectum downward.
3 Others: internal hemorrhoids and rectal polyps often prolapse, pulling the rectal mucosa downwards to induce mucosal prolapse.
At present, there are two theories that cause complete rectal prolapse: 1. Sliding hernia theory: due to increased intra-abdominal pressure and pelvic floor tissue relaxation, the rectal bladder depression or rectal uterine depression is pushed down and displaced. , Press the anterior wall of the rectum into the ampulla of the rectum, and finally protrude outside the anus. 2 Intussusception theory: Intussusception begins at the junction of the rectum and sigmoid colon. Under the influence of factors such as increased abdominal pressure and pelvic floor relaxation, the intussusception part continues to move downwards, eventually causing the rectum to protrude outside the anus.
The pathological change of rectal mucosal prolapse is that the connective tissue between the lower rectal mucosa and the muscular layer is too loose, and the mucosal layer moves down; complete prolapse is that the connective tissue around the fixed rectum is too loose, so that the entire rectal wall moves down. The prolapsed rectal mucosa may have inflammation, erosion, ulcers, bleeding, and even incarcerated necrosis. Anal sphincter muscles continue to stretch and passively relax, which can cause anal incontinence, and prolapse worsens after incontinence. Rectal prolapse in young children is mostly mucosal prolapse, which usually heals on its own before 5 years old; as long as the factors that cause prolapse exist in adult rectal prolapse, the gray is getting worse.
Clinical manifestations: The main symptom is prolapse of a mass from the anus. The swelling is small when starting, and it comes out during defecation, and then resets itself after defecation. Later, the body will be removed to reduce poverty and increase in volume. After defecation, it must be dragged back into the anus by hand, accompanied by incomplete defecation. Finally, when coughing, strenuously or even standing up, she comes out immediately. Subsequently, the prolapse worsens, causing varying degrees of anal incontinence, often accompanied by mucus outflow, resulting in eczema and itching of the perianal skin. Due to difficulty in emptying the rectum, constipation often occurs, and the number of stools increases, and it becomes sheep feces. The mucous membrane is eroded and blood flows out after ulceration. Internal prolapse often has no obvious symptoms and is occasionally discovered during colonoscopy.
During the examination, the patient was asked to squat down and hold his breath to prolapse the rectum. Partial prolapse can be seen as a round, red, smooth surface mass. The length of mucosal folds in a "radial" prolapse is generally no more than 3 cm; digital examination only touches two folded mucous membranes; the anal sphincter is weak in contraction during digital rectal examination. When the patient is instructed to contract forcefully, only a slight contraction is felt. If rectal prolapse is incomplete, there are "concentric rings" folds on the surface of the mucosa, which drag out longer, and the prolapsed part is a two-layer intestinal wall fold, which is thicker on palpation; during digital rectal examination, the anus is enlarged and the anal sphincter is relaxed. Weakness; when the anal canal is not prolapsed, there is a deep annular groove between the anus and the prolapsed anal canal.
Colonoscopy of the sigmoid colon showed congestion and edema of the distal rectum. The proximal rectum was inserted into the distal rectum during defecation angiography.
Treatment: The treatment of rectal prolapse varies with age and severity, and is mainly to eliminate the predisposing factors of rectal prolapse; rectal prolapse in children is mainly treated conservatively, and the recognized complete rectal prolapse is mainly treated by surgery .
1. General treatment. Children with rectal prolapse may heal itself. You should pay attention to shortening the time of defecation, reset the prolapsed rectum immediately after defecation, take the prone position, and fix the buttocks with tape. Adults should also actively treat constipation, cough and other diseases that cause increased abdominal pressure to avoid aggravation of prolapse and recurrence after surgical treatment.
2 Injection therapy The sclerosing agent is injected into the submucosa of the prolapsed site to cause aseptic inflammation of the mucosa and muscle layer, and adhesion and fixation. Commonly used hardeners are 5% carbolic acid vegetable oil, 5% quinine hydrochloride urea aqueous solution. The effect is good for children and the elderly, and adults are prone to relapse.
3 Surgical treatment There are many surgical methods for adult complete rectal prolapse, each with its advantages and disadvantages and different recurrence rates. There are four surgical approaches: transabdominal, transperineum, transabdominal perineum, and transsacral. The first two approaches are more widely used.
Rectal suspension fixation is effective in treating rectal prolapse. After the rectum is freed during the operation, the rectum and sigmoid colon can be fixed on the surrounding tissues by various methods, mainly on the tissues on both sides of the sacrum. Be careful not to damage the peripheral nerves and the presacral nerve plexus; the loose pelvic floor can be sutured at the same time Fascia, levator ani muscle, lengthy sigmoid colon and rectum are removed.
The perineal surgery is safe, but the recurrence rate is high. The prolapsed rectum and even the sigmoid colon can be directly excised and sutured from the anus. Rectal mucosal prolapse can be removed by hemorrhoid ring resection. Elderly and weak people can simply perform anal ring constriction, that is, under local anesthesia or spinal anesthesia, make a small incision on the front and back of the anus, use a vascular forceps to subcutaneously go around the anus for a circle of separation, use metal wire or polyester Wrap around the anus under the skin, remove the implant under the skin after 2-3 months, shrink the anus to prevent anal prolapse.
Part VI: Rectal polyps (combined with multimedia)
Rectal polyps generally refer to raised lesions that protrude from the rectal mucosa to the intestinal cavity. There are many types of polyps and they are very common. Except for juvenile polyps, which mostly occur in children aged 5-10 years, other rectal polyps mostly occur in children over 40 years old. The older the age, the higher the incidence. The rectum is a frequent site of polyps, and colon polyps are often combined.
Pathologically, polyps are often divided into neoplastic polyps and non-neoplastic polyps. Neoplastic polyps can be divided into tubular adenomas, villous adenomas and mixed adenomas, which have a tendency to become malignant. Non-neoplastic polyps include hyperplastic (metaplastic) polyps, inflammatory polyps, juvenile polyps, etc. Tubular adenomas are the most common, most of them are single, pedicled, generally less than 1 cm in diameter, and rarely become cancerous, such as rapid increase in volume and dysplasia, the cancer rate increases. Villous adenoma, also known as papillary adenoma, is villous and cauliflower-like protruding on the mucosal surface. The tumor is soft in texture, broad-based, sessile, and larger than tubular adenomas. It is more common in adults and more men than women. 90% occurs in the lower part of the rectum and sigmoid colon, prone to cancer. Juvenile polyps, also known as congenital polyps, are hampered polyps, which mainly occur in children under 10 years old. About 70%-80% occur in the rectum. They are mostly single, less than 1 cm. They tend to disappear naturally after puberty. Inflammatory polyps (pseudopolyps) occur in the regeneration and repair stage of colitis disease, and are more common in ulcerative colitis, crohn disease, intestinal tuberculosis, schistosomiasis, etc., mostly multiple, small in size, and may increase when the disease course is longer. Large, the histology shows fibrous granulation tissue. Hyperplastic polyps (metaplastic polyps) usually occur in the rectum, and usually start after 40 years of age. The incidence increases with age. Familial adenomatous polyposis is an autosomal phenotypic hereditary disease. The large intestine is full of polypoid adenomas of varying sizes, pedicled or sessile, and has a high tendency to become cancerous. It usually occurs after 12 years of age.
Clinical manifestations: Small polyps rarely cause symptoms. The most common symptom after polyps enlargement is internal rectal bleeding, which usually occurs after defecation. It is bright red blood and does not mix with feces. Most are intermittent bleeding, and the amount of bleeding is small, rarely causing anemia. Polyps at the lower part of the rectum can protrude out of the anus during defecation, appear bright red, cherry-like, and retract by themselves after defecation. When rectal polyps are complicated by infection, mucus, pus, bloody stools, frequent stools, tenesmus, and incomplete defecation may occur.
Diagnosis: Diagnosis mainly relies on digital rectal examination and rectal sigmoidoscopy. A soft, pedunculated, mobile, smooth, spherical mass can be felt in the rectum when the pointer is pointed. Rectal, sigmoidoscopy can directly observe the shape of polyps. After seeing rectal polyps, all large intestines should be further examined, because polyps are often frequent. Proctoscopy or sigmoidoscopy taking biopsy for pathological examination is an important method to determine the nature of polyps and determine the treatment method.
1Electrocautery resection If the polyp is located in a high position and cannot be removed from the anus, the polyp should be exposed through a proctoscope, sigmoidoscopy or fiber colonoscope, and the pedicled polyp should be removed by electrocautery with a snare. Guangji polyp electrocautery is not safe.
2 Transanal resection is suitable for lower rectal polyps. Perform under sacral anesthesia. After expanding the anus, use tissue forceps to pull out the polyp. For benign polyps with pedicles, ligate the pedicle and remove the polyps; for broad-based polyps, remove part of the mucosa including the surrounding polyps and suture the wound; if It is a villous adenoma, the tangent line is visible to the naked eye, and the margin of the adenoma is not less than 1 cm
3 Anoscopy microsurgical resection is suitable for local resection of adenomas and early rectal cancer in the upper rectum. After anesthesia, insert a microsurgery anoscope through the anus, enlarge the surgical field through a TV screen, and remove polyps under the microscope. Compared with electrocautery resection, the advantage is that the wound after resection can be sutured to avoid complications such as postoperative bleeding and perforation.
4 Laparotomy is suitable for cancerous polyps that are difficult to completely resect under endoscopy and are located in a high position, or wide-based polyps with a diameter greater than 2 cm. The tumor has become cancerous during laparotomy and should be treated according to the principles of rectal cancer surgery. Familial polyps will develop into cancer sooner or later, and radical surgery must be based on the distribution of rectal polyps to decide whether to preserve the rectum; rectal resection or rectal mucosal stripping is possible, transrectal mucosal stripping, transrectal muscle sheath and ileum storage bag anal canal anastomosis Wait.
In addition, inflammatory polyps are mainly used to treat primary bowel disease; hyperplastic polyps have no obvious symptoms and do not require special treatment.
1 "Surgery" unified textbook fifth edition.
2 Huang Jiasi Surgery (Fifth Edition)
3 The second edition of the original British edition of "Anorectal Surgery" by Keighley et al., UK.
4 Wang Jianping and Zhan Wenhua edited "Gastrointestinal Surgery".