Sigmoid colon torsion

　　First, Etiology

　　The sigmoid colon loop is prone to volvulus, which is related to the following factors.

　　1. Anatomical Factors:The sigmoid colon is abnormally long, and the attachment site of the sigmoid colon mesentery is narrow, with the proximal and distal intestinal tubes close to each other. The mobility of the intestinal loop is large, which is the anatomical basis for volvulus.

　　2. Pathological Factors:Based on the above anatomical factors, such as pelvic inflammation, adhesion, and scar formation, the root of the sigmoid colon mesentery may become shortened. Enlarged lymph nodes, tumors, cysts, and other masses within the intestinal wall or mesentery may be predisposing factors for volvulus.

　　3. Changes in Colonic Motility:Overeating, excessive fiber residue in food, constipation, intestinal ascaris clumps, congenital megacolon, and other factors can increase the weight of the intestinal loop itself. Due to gravity, sudden changes in body position and posture are prone to volvulus. Abuse of laxatives, psychiatric patients, abdominal trauma can cause hyperperistalsis. Elderly people with long-term bed rest and hypokalemia often have intestinal paralysis. Practice has proven that abnormal changes in intestinal motility are closely related to intestinal volvulus.

　　Second, Pathogenesis

　　Sigmoid colon volvulus can occur in either clockwise or counterclockwise directions. The degree of influence on intestinal blood circulation caused by volvulus mainly depends on the extent and tightness of the volvulus. For example, when the volvulus is 180°, mesenteric blood circulation can be unobstructed, and only the rectum located behind the sigmoid colon wall is compressed, resulting in a simple intestinal obstruction. When the volvulus exceeds 360°, it will inevitably cause绞窄性闭襻性肠梗阻. With an increase in the volume of gas and fluid in the intestinal lumen, the sigmoid colon becomes overly distended due to the volvulus. Initially, venous blood flow stops, leading to congestion and thrombosis, which further aggravates circulatory disorders. Arterial blood flow will also stop. The volvulus forms an ideal anaerobic environment, where anaerobic and aerobic bacteria can multiply simultaneously in large quantities within a few hours, destroying the intestinal mucosal barrier function, increasing permeability, and allowing intestinal bacteria and certain toxic substances to leak into the peritoneal cavity and be absorbed into the blood. On the other hand, they can directly invade the portal venous system, causing sepsis and toxicosis. Severe cases may ultimately die from a mixed shock of infectious and hypovolemic conditions.

　　Acute sigmoid colon volvulus often complicates with intestinal necrosis or perforation, presenting clinical symptoms of acute abdomen.

　　Cecum volvulus is a complication of sigmoid volvulus, presenting with acute colicky pain in the right lower quadrant, accompanied by vomiting, abdominal distension, non-passage of gas and feces, and typical symptoms of intestinal obstruction. A tender mass can often be palpated in the right upper or middle quadrant, with tympany on abdominal percussion and varying degrees of peritoneal irritation signs. Transverse colon volvulus is mostly functional, presenting as acute upper abdominal pain, which improves after defecation and排气. Volvulus caused by adhesions is often due to abdominal inflammation or surgery, with symptoms of绞痛 in the upper middle abdomen, accompanied by nausea, vomiting, constipation, and a distended, tender colon tube can be palpated in the upper middle abdomen.

　　Patients with sigmoid volvulus often have a history of chronic constipation, with abdominal pain and progressive abdominal distension as the main clinical manifestations. According to the acuteness of onset, it can be divided into subacute type and acute fulminant type.

　　1. Subacute type:Common, accounting for 75% to 85% of sigmoid volvulus cases, mostly in elderly patients, with a slow onset, a history of irregular abdominal pain attacks and pain relief after defecation and排气, with the main symptoms being persistent, lower abdominal distension, with intermittent exacerbation, without defecation and排气; nausea and vomiting, but with less vomiting, and fecal odor in late vomiting, with progressive abdominal distension as a characteristic.

　　Physical examination: The patient generally has a good condition, with obvious abdominal distension, asymmetric distension, more severe on the left side, with only mild tenderness in the abdomen except for bowel necrosis, without significant peritoneal irritation signs. Sometimes, a tender, cystic mass can be felt, and auscultation reveals high-pitched bowel sounds or water-hammer sounds.

　　Elderly patients or those with weakened physical condition may have shock symptoms when the course is long.

　　2. Acute type:Rare, more common in young people, with an acute onset and rapid progression, presenting as typical symptoms of low intestinal obstruction, severe abdominal pain, diffuse abdominal pain; early and frequent vomiting, leading to shock due to significant fluid loss.

　　Physical examination: Abdominal distension is less than in subacute cases, with marked peritoneal irritation signs. There is tenderness and rebound tenderness throughout the abdomen, marked abdominal muscle tension, disappearance of bowel sounds, suggesting possible bowel necrosis.

　　1. Prevention

　　If sigmoid volvulus is caused by non-congenital developmental factors, preventive measures should be taken against the pathogenic factors (such as elderly individuals with habitual constipation, intra-abdominal adhesions after surgery, consumption of high-fiber foods, antecubital exercise after a full meal, etc.).

　　2. Prognosis

　　Timely treatment of sigmoid volvulus usually results in a good prognosis. However, if there is intestinal strangulation or even rupture and perforation, the prognosis is poor. If not treated promptly or properly, the mortality rate is high. If sigmoid volvulus improves after non-surgical treatment, further examination of the cause of the disease should be carried out, and if necessary, elective surgery can be performed to eliminate the cause to prevent recurrence.

　　1. X-ray examination

　　1. Abdominal X-ray film:Visible a large, isolated intestinal loop with marked air distension on the left side of the abdomen, extending from the pelvis to the upper middle abdomen, even below the diaphragm, occupying most of the abdominal cavity, forming what is called the 'curved tube' sign. Within the large sigmoid colon loop, it is often possible to see two liquid-gas interfaces at different levels, with varying degrees of distension in the left and right halves of the colon and small intestine.

　　2. Barium enema radiography:Barium is obstructed at the rectosigmoid junction, with the tip of the barium column in the shape of a cone or beak, and the volume of enema often does not reach 500ml (normally over 2000ml can be infused), and it flows outwards, which can prove that there is an obstruction in the sigmoid colon. This examination is only suitable for early twists with good general condition. When there are signs of peritoneal irritation or marked abdominal tenderness, it is contraindicated to perform barium enema examination, otherwise, there is a risk of bowel perforation.

　　Second, sigmoidoscopy examination.

　　Third, low-pressure saline enema experiment

　　The infusion of normal saline (500ml) can prove that the twist obstruction is located in the sigmoid colon.

　　1. Foods that are good for the body for sigmoid colon twist:

　　Diet should be high in protein and nutrition, with an abundance of fruits and vegetables such as bananas, strawberries, and apples. These are rich in nutrients and can enhance immunity by eating more foods like propolis. This can strengthen an individual's ability to resist disease. In addition, a reasonable diet should be balanced, with attention to adequate nutrition.

　　2. Foods to avoid for sigmoid colon twist:

　　Avoid smoking, drinking, spicy foods, greasy foods, smoking, and alcohol. Avoid eating cold foods. To avoid the recurrence of the disease.

　　First, treatment

　　Sigmoid colon twist was first described by Von Rokitansky in 1836. For more than 50 years after that, surgery to untwist the bowel was considered the standard treatment method. Since the postoperative mortality rate was still high, it was soon realized that the prognosis was more affected by the presence or absence of bowel necrosis, and attention was also paid to the fact that the choice of treatment was determined by the presence or absence of bowel necrosis, emphasizing that it is very important to handle the two different situations differently.

　　1. Non-surgical treatment:Indicated for early twists with good general condition and mild clinical symptoms. For elderly and weak patients, if it is estimated that it has not developed into strangulated intestinal obstruction, non-surgical therapy can be considered. However, during the active treatment process for sigmoid colon twists, the patient's condition should be closely observed, including clinical symptoms, signs, and laboratory test results. Even experienced surgeons, in cases where preoperative diagnosis based on experience does not indicate necrosis, there is still a risk of about 30% that surgery confirms the occurrence of strangulation. Therefore, there is a risk of delaying the treatment of strangulated intestinal obstruction during non-surgical treatment for early intestinal twists. If symptoms and signs do not improve but worsen after 24 hours of conservative treatment, it is advisable to perform an operation to explore.

　　During the non-surgical treatment process, in addition to fasting, gastrointestinal decompression, fluid replacement, maintaining water and electrolyte balance, and early use of antibiotics to prevent infection, treatment for the twisted sigmoid colon is also needed.

　　(1) Sigmoidoscopy to relieve distension: The patient is in the knee-chest position, and the sigmoidoscope is inserted from the anus to the twist site. At this time, the mucosa should be carefully examined. If there is a change in mucosal color or the presence of blood-stained fluid, it should be suspected that the intestinal wall has necrosis, and this method is obviously not suitable. If the mucosa appears normal, a smooth stomach tube or rectal tube is carefully passed through the twist site into the dilated sigmoid colon pouch, a large amount of gas and intestinal contents will be smoothly discharged, emptying the dilated intestinal tract and the twist may be复位自行。

　　(2) Enema Therapy: For patients with sigmoid volvulus, 500ml of warm, hypertonic saline or soap water can be slowly infused into the rectum and sigmoid colon to promote the reduction of sigmoid volvulus through hydrostatic pressure. In order to achieve the purpose of safely handling emergencies, the enema pressure should not be too high, and it should not be reused to avoid necrosis and perforation of the twisted intestinal tract.

　　(3) Jostling Therapy: In recent years, there have been reports in China that this method has been used in the early stage of intestinal torsion, which can timely achieve reduction of sigmoid volvulus. However, it must be decided according to the patient's overall condition and the operator's experience, and it is not suitable for patients with peritonitis.

　　Ma Yong and others have encountered several cases of intestinal obstruction patients who were ready for surgery, and suddenly a large amount of feces was discharged from the anus during the journey to the operating room or after epidural anesthesia in the lateral recumbent position. This indicates that jostling and changes in body position can relieve intestinal obstruction. However, this can only show that jostling has a certain effect.

　　Method: The patient should be in a knee-elbow position, and the operator needs to straddle the patient's back, holding the patient's lower abdomen with both hands, gently massaging, then suddenly relaxing the abdomen after raising it, gradually increasing the jostling below the navel, or swinging the abdomen left and right, up and down repeatedly, for 3-5 minutes. After 1-2 jostles, the symptoms are usually relieved. If there is still no defecation and abdominal pain relief after 3-5 consecutive jostles, other treatments should be used.

　　2. Surgical Therapy:

　　(1) Indications for Surgery: At present, the treatment principle for sigmoid volvulus in China and abroad still mostly advocates the active adoption of surgical treatment. Because sigmoid volvulus is a closed-loop, strangulated intestinal obstruction, delayed treatment or inappropriate methods still have a high mortality rate. Boulvin reported that 51 patients with sigmoid volvulus were treated, resulting in 14 deaths (27%). Ma Yong and others advocate that surgery should be performed in the following situations: ① Complicated sigmoid volvulus with peritonitis, intestinal necrosis, and shock. ② Non-surgical therapy is ineffective, the course of the disease exceeds 48h, and there is a tendency towards intestinal necrosis. ③ Recurrence after surgical reduction, or after reduction with non-surgical treatment, due to the redundancy of the sigmoid colon, radical sigmoid colectomy should be performed to prevent recurrence.

　　(2) Surgical Method:

　　①Sigmoid Volvulus Reduction Surgery: Applicable to sigmoid volvulus without intestinal necrosis. An incision is made beside the midline of the lower left abdomen, and after laparotomy, the dilated and twisted sigmoid colon can be seen. The operator inserts the right hand into the pelvic cavity, guiding the assistant to insert the肛管 through the anus, passing through the twist, directly reaching the dilated sigmoid colon. Immediately, a large amount of gas and loose stool is discharged from the肛管, and the dilated intestinal tract is immediately relieved. The intestinal loop can be rotated in the opposite direction of the twist to achieve reduction. If the intestinal tract is significantly dilated and the肛导管 cannot enter the twisted intestinal loop, place a purse-string suture on the mesenteric side of the dilated intestinal loop, puncture and aspirate to reduce pressure in the center of the suture. After the decompression is completed, tie the purse-string suture, and pull the sigmoid colon out of the abdomen for reduction. However, this puncture method should be avoided as much as possible to prevent contamination of the abdominal cavity. After reduction, the tip of the肛管 should be placed beyond the distal obstructed loop of the intestinal cavity and retained, and it should be removed after 3 days. Although this operation is simple and effective, the chance of recurrence is high. Therefore, in recent years, it is more commonly advocated to fold the redundant part of the sigmoid colon parallelly after reduction and fix it to the inner side of the descending colon, which is meaningful for preventing recurrence.

　　② Sigmoid colon resection: The vitality of the intestinal segment should be carefully observed after the torsion is复位. The indications for resection are: A. Intestinal necrosis, loss of vitality; B. Torsion accompanied by other organic lesions; C. Prevent recurrence after复位.

　　After the strangulating factors are relieved, observe the signs of intestinal tract vitality loss. It can be determined that intestinal necrosis occurs when the following characteristics are present and should be resected: A. The color of the intestinal tract is dark black or purple black, and there is no improvement after hot compress observation; B. The intestinal wall loses tension, the intestinal tract is瘫痪扩张, and the serosa loses luster and elasticity; C. There is no peristalsis, and there is no contraction response to stimulation; D. The mesenteric artery has no pulsation, and the veins and small branches have extensive thrombosis; E. The peritoneal fluid is dark red, turbid, and has a fecal smell; F. The intestinal mucosa is eroded, shows patchy necrosis, and is easy to fall off.

　　(3) Selection of surgical methods:

　　① One-stage resection and end-to-end anastomosis: One-stage resection and anastomosis is the most ideal operation because it can prevent recurrence and achieve cure in one operation. However, it was previously believed that due to the special characteristics of local blood supply and intestinal bacteria in the left colon, one-stage resection and anastomosis of the necrotic segment was extremely dangerous. To prevent leakage, staged surgery should be performed. First, the necrotic intestinal segment should be resected and double腔造瘘 or proximal造瘘 should be performed, and the distal end should be closed. Later, a second-stage closure and reimplantation operation should be performed. In recent years, some people have reported that even if the sigmoid colon is twisted and necrotic, as long as the general condition of the body allows, it is still advocated to strive for one-stage resection and anastomosis. Xiangya First Hospital of Central South University has carried out a large number of one-stage resection and anastomosis after lavage with physiological saline and antibiotics in the intestinal tract, and has achieved satisfactory results.

　　② Colostomy: For patients with severe necrosis of the intestinal tract, late disease course, or delayed treatment, with infection in the abdominal cavity and severe toxic symptoms, life-saving should be the principle, and necrotic intestinal loop resection and double腔造瘘术 should be performed. If the torsion involves a large range of sigmoid colon and rectum, and the distal rectum cannot reach the abdominal wall to make a distal ostomy, Hartman's resection can be chosen, and the anastomosis between the proximal and distal ends can be reconstructed after about 3 months after the operation.

　　II. Prognosis

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