Postoperative internal hernia

　　There are many etiologies of internal hernia after resection, and the main reasons are as follows:

　　One, Postoperative anatomical abnormality

　　Internal hernia after gastric resection often occurs after Billroth II operation, and the abnormal anatomical relationship formed by the gastric jejunal anastomosis is the potential basis for the occurrence of internal hernia.

　　1. Formation of an abnormal posterior space: The existence of the posterior space is just the pathological basis for the occurrence of internal hernia, whether internal hernia occurs is still related to many factors: ① Postoperative time: In the early postoperative period, the posterior space adhesion has not yet formed, and the chance of internal hernia is relatively high. As the postoperative time extends, the posterior space gradually becomes adherent and occluded, and the chance of internal hernia will greatly decrease. ② Size of the posterior space: The size of the anastomotic posterior space is related to the extent of gastric tissue resection, the length of the input loop jejunum, the method of gastric jejunal anastomosis (whether the proximal jejunum is on the small curvature or the great curvature), the position of the transverse colon mesentery opening, and the height of the fixation on the residual stomach.

　　2. Formation of an abnormal transverse colon mesenteric cleft: The inconstant fixation of the transverse colon mesentery to the gastric wall can lead to suture loosening, wide suture spacing, or forgetting to repair and fix, and the small intestinal loop can herniate into the gap between the stomach and the transverse colon mesentery.

　　Two, Excessively long input loop

　　An excessively long input loop increases the posterior space, increasing the chance of internal hernia of the input loop and hernia of the jejunum into the output loop, which is another important factor in the occurrence of internal hernia.

　　Three, Postoperative adhesion, improper diet, and changes in position

　　In some cases, postoperative adhesion of varying degrees, as well as changes in the quality and quantity of postoperative diet, may promote hyperperistalsis and intestinal dysfunction, especially when there is a sudden change in position, which increases the posterior space, combined with increased abdominal pressure, causing the mesentery to pull upwards, all of which have varying degrees of influence on the occurrence of posterior hernia.

　　The main complications of internal hernia after resection include the following two aspects:

　　One, Rupture of the duodenal stump

　　Internal hernia occurs in the recent postoperative period, due to the incomplete healing of the duodenal stump, and the obstruction of the input loop caused by the internal hernia of the input loop can lead to accumulation of bile and pancreatic juice in the duodenal lumen, resulting in retentional dilatation, increased intraluminal pressure, and rupture.

　　Two, Acute pancreatitis

　　A small number of patients may develop acute pancreatitis due to internal hernia, the main reasons being:

　　1. Internal hernia of the input loop causes obstruction of the input loop, followed by accumulation of bile and pancreatic juice in the duodenal lumen, increased intraluminal pressure, leading to retrograde reflux of duodenal fluid into the pancreatic duct, and inducing acute pancreatitis.

　　2. Internal hernia of the output loop can also compress the jejunum of the input loop, causing obstruction of the input loop, and then induce acute pancreatitis.

　　Postoperative internal hernia after subtotal gastrectomy often occurs in the early postoperative period, with the shortest occurring 2 days after surgery, about half occurring within one month after surgery, 1/4 occurring between the 2nd and 12th month after surgery, and the remainder occurring after one year of surgery.

　　One, Clinical manifestations of acute intestinal obstruction

　　: The main manifestations of acute intestinal obstruction are acute high-grade complete small bowel obstruction. Most cases have an acute onset and a severe clinical course. If diagnosis and treatment are not timely, the mortality rate can reach up to 40%. Once internal hernia occurs after subtotal gastrectomy, a large amount of small intestine often continues to herniate into the posterior space. Since it is mostly the proximal jejunum that herniates, the patient often has little abdominal distension but frequent vomiting. However, the clinical symptoms and signs of internal hernia of the proximal loop and distal loop are different.

　　1. Internal hernia of the proximal loop: It presents as persistent pain in the upper abdomen, with less vomiting and vomiting without bile, little abdominal distension, and a palpable tender mass in the upper abdomen slightly to the left. Bowel sounds are usually not hyperactive, and gurgling sounds are rarely heard.

　　2. Internal hernia of the distal loop: It presents as intermittent sharp pain in the upper abdomen or slightly to the left of the upper abdomen, with most patients accompanied by distension and pain in the lumbar and back regions, large-volume vomiting containing bile, relatively significant abdominal distension, and bowel sounds or gurgling sounds. There are no abdominal masses. X-ray examination shows delayed emptying of contrast material in the remnant stomach and obstruction of the distal loop, with the distal loop located behind the proximal loop in the oblique view. In addition, the proximal loop of the jejunal loop in patients with internal hernia of the distal loop can also be compressed at the hernia ring, causing obstruction, and thus showing symptoms and signs of both jejunal proximal loop and distal loop obstruction.

　　2. Diffuse peritonitis, toxic shock

　　With the progression of the disease, intestinal distension occurs, followed by circulatory impairment of the intestinal wall, and even strangulation. If the strangulation is not released in time, the circulatory impairment of the intestinal wall worsens, leading to necrosis of the small intestine and the appearance of symptoms of diffuse peritonitis. Due to necrosis of the small intestine, diffuse peritonitis, and the absorption of a large amount of toxins, patients can quickly develop toxic shock, and some patients have mucous bloody stools. Physical examination shows significant abdominal distension, decreased or absent bowel sounds, and obvious peritoneal irritation signs. Palpation shows mobile dullness when percussed, and abdominal puncture may yield bloody fluid. Systemic symptoms include fever, tachycardia, reduced pulse pressure, oliguria, and little improvement in symptoms after anti-shock treatment.

　　3. Disturbance of water, electrolyte, and acid-base balance

　　Due to the inability to eat and frequent vomiting, a large amount of gastrointestinal fluid and bile are lost, causing the obstructed intestinal tract to become overly distended, compressing the intestinal wall and causing venous return obstruction. Plasma leaks into the intestinal lumen and peritoneal cavity, leading to massive blood loss due to intestinal strangulation, causing severe dehydration, reduced blood volume, and metabolic acidosis.

　　The occurrence of internal hernia after subtotal gastrectomy is closely related to the surgical method and operation, and targeted measures can be taken to reduce the occurrence of internal hernia:

　　1. Choose the Billroth I technique for anastomosis.After a subtotal gastrectomy, the Billroth I technique of gastrojejunal anastomosis is used, which brings the gastrointestinal tract close to normal anatomical and physiological status, with fewer complications. To date, there have been no reports of internal hernia occurring after Billroth I gastrojejunal anastomosis in subtotal gastrectomy patients.

　　2. Eliminate or reduce the posterior space.The posterior space after gastrojejunal anastomosis is a potential basis for internal hernia. Appropriate measures can be taken during surgery, such as shortening the jejunal loop, to reduce the posterior space, which is conducive to reducing the chance of posterior hernia. When performing surgery for an internal hernia, it is routine to suture the posterior space after reduction to prevent recurrence of internal hernia.

　　3. Shorten the length of the input loop.A large number of literature reports have confirmed that the occurrence of internal hernia is closely related to the length of the input loop. Therefore, whether it is an anterior or posterior gastric jejunal anastomosis, shorten its length as much as possible to make the posterior space smaller, which will greatly reduce the probability of internal hernia. In patients with thick omentum, it is best to remove it during the anterior gastric jejunal anastomosis to shorten the length of the input loop and reduce the posterior space.

　　4. Choose an appropriate anastomosis method.Since most individuals have the duodenojejunal flexure on the left side of the spine, the small curvature anastomosis of the jejunal input loop in front of the colon can cause anatomical disorders such as anterior and posterior crossing of the jejunal loop and its mesentery, and requires a longer input loop, thus increasing the risk of postoperative internal hernia. It is recommended to adopt a posterior colon input loop small curvature anastomosis or an anterior colon large curvature anastomosis as much as possible to shorten the length of the jejunal input loop and avoid the crossing change of the bowel and mesentery.

　　5. The recovery of postoperative diet and physical labor should be appropriate.The quality and quantity of diet are closely related to gastrointestinal dysfunction, especially in the case of abdominal surgery where there is a certain amount of adhesion in the abdominal cavity. After a heavy meal, vigorous physical activity or overeating is more likely to cause gastrointestinal motility disorders and trigger internal hernia, which should be avoided as much as possible. After gastric surgery, it is advisable to eat in small and frequent meals, light and easy-to-digest food, and avoid vigorous physical activity after meals.

　　6. The repair of the mesenteric opening should be reliable.The opening of the transverse colon mesentery is at the root, and the repair and fixation should be reliable, not too high, to avoid the occurrence of a tear in the transverse colon mesentery.

　　The main examination methods for internal hernia after resection are as follows.

　　1. Blood examination:

　　1. White blood cell count and classification: The number of white blood cells generally increases. The wider the scope of inflammation and the more severe the infection, the more obvious the increase in white blood cell count.

　　2. Hemoglobin and hematocrit: In cases of severe dehydration, blood becomes concentrated, and hemoglobin and hematocrit slightly increase.

　　2. Serum electrolytes (K, Na, Cl-): Serum electrolytes can reflect the status of water, electrolytes, and acid-base balance.

　　3. Blood gas analysis: Blood gas analysis shows a decrease in pH, SB, and a negative BE, with a compensatory decrease in PCO2, suggesting the possibility of metabolic acidosis.

　　4. Serum amylase: Serum amylase levels exceeding 500U suggest acute pancreatitis, as serum amylase increases within 2-12 hours after onset and returns to normal within 48-72 hours. At this time, the total amount of amylase in 2 hours of urine can be measured, and when the amylase level in urine per hour exceeds 300U, the accuracy of diagnosis is relatively high.

　　5. Amylase/creatinine clearance value: During acute pancreatitis, the renal clearance of amylase is higher than creatinine, so when this value is greater than 5, it highly suggests acute pancreatitis. If it is a simple input loop obstruction, serum amylase may increase, but the amylase/creatinine clearance value does not increase, which is significant for differential diagnosis.

　　Patients with postoperative internal hernia should drink more water and eat light, nutritious liquid and semi-liquid foods. Supplement a variety of vitamins, eat more fresh vegetables and fruits. Avoid spicy food such as chili, Sichuan pepper, raw scallions, raw garlic, white wine, and frozen food.

　　Due to the relationship between intestinal peristalsis and gravity, once this disease occurs, it often becomes more severe, leading to rapid development of intestinal strangulation and necrosis, and the occurrence of diffuse peritonitis and toxic shock. To reduce mortality, prevent short bowel syndrome and malnutrition caused by the resection of a large amount of necrotic intestinal tract, early diagnosis and laparotomy are the key to treatment.

　　I. Preoperative Preparation:

　　Patients with this disease have undergone surgery in the recent past, plus intestinal obstruction caused by internal hernia, the general condition is usually poor. Attention should be paid to improve the overall condition before surgery, quickly replenish blood volume, correct metabolic acidosis, apply broad-spectrum antibiotics for anti-infection, and treat toxic shock.

　　II. Key Points of Surgery:

　　1. Repositioning of the intestinal loop: For patients with severe expansion of the herniated intestinal loop and difficulty in repositioning, it is advisable to first reduce the intraluminal pressure of the intestinal cavity before repositioning. When repositioning the intestinal loop, the herniated intestinal loop should be pushed back in the opposite direction of the hernia, and it is forbidden to pull with force.

　　2. Resection of necrotic intestinal loop and gastrointestinal reconstruction: For incarcerated intestinal loops that are strangulated and necrotic, the necrotic intestinal loop should be resected, and the gastrojejunal Roux-Y anastomosis should be performed instead. If there is a suspicion of blood supply in the herniated intestinal loop, measures such as warm saline pad hot compress, 0.25% to 0.5% procaine blockage of the mesentery, and oxygen inhalation to increase the blood oxygen partial pressure in the body can be taken to try to restore the vitality of the suspicious intestinal tract, and then decide whether to resect or retain, or resect less of the related intestinal loops. For longer input loops, side-to-side anastomosis of the input and output loops or Roux-Y anastomosis can be performed.

　　3. Close the posterior space: The posterior space of patients with internal hernia after gastric resection is generally significantly expanded, so the intestinal loop must be closed after repositioning, otherwise it is easy to recur again.

　　4. Check the duodenal残端: During surgery, it is necessary not to neglect the examination of the duodenal残端, especially for patients who develop internal hernia early after surgery. If there is a rupture of the duodenal残端, duodenal fistula or intraperitoneal double tube drainage should be performed.

　　For patients with hernia of the transverse mesocolon, the incarcerated intestinal tract should be repositioned during surgery, and the transverse mesocolon should be re-fixed to the stomach wall to eliminate the gap between them.