1, definition: abdominal wall incisional hernia is due to the abdominal wall incision of the fascia and/or muscle layer failed to completely heal, under the action of intra-abdominal pressure and the formation of hernia, its hernia sac may have complete or incomplete peritoneal epithelium. A subincisional myofascial defect of the abdominal wall may be palpable on examination or detected on imaging, which may or may not be accompanied by protrusion of intra-abdominal organs. The etiology of abdominal wall incisional hernia is complex and varied, and may include factors from both the patient’s own body and those related to the surgical operation. (1) The patient’s age, weight, nutritional status and other factors that cannot be changed or are not easy to change affect the healing of the abdominal wall incision, such as advanced age, malnutrition, diabetes mellitus, obesity, long-term use of steroid hormones, etc. are not conducive to the recovery of surgical trauma, which includes the healing of the incision. (2) Improper suture closure of the incision during surgery is one of the causes of incisional hernia. (3) Postoperative hematoma, infection or aseptic necrosis and liquefaction of subcutaneous fat in the incision is also a cause of incisional hernia. (4) Postoperative abdominal distension and increased intra-abdominal pressure, such as chronic cough and chronic obstructive pulmonary disease (COPD) can affect the healing of the abdominal wall incision, which is one of the factors for the formation of incisional hernia. 2, Pathology and pathophysiology Local skin changes Most commonly seen in large incisional hernias, thinning of the skin or scar tissue at the base of the hernia sac and color changes. Changes in the myofascia at the edge of the hernia After the incisional hernia occurs, the abdominal wall muscles and fascia contract and shift to the sides of the hernia ring, myofascial atrophy, fatty degeneration and tendon membrane retraction occur, making the edge of the defect hard. This is especially true of incisional hernias in certain areas, such as subxiphoid, subcostal and suprapubic, where part of the defect edge is only bony or cartilaginous tissue. Systemic effects of increased hernia sac volume in incisional hernia The normal function of the abdominal wall is maintained by the four pairs of muscles of the abdominal wall (rectus abdominis, external abdominal obliques, internal abdominal obliques, and transversus abdominis) in conjunction with the diaphragm. Thoracic and abdominal pressures interact and coordinate to participate in and regulate important physiologic processes such as respiration and retrograde blood flow. When there is a defect in the abdominal wall (incisional hernia), the defective portion of the abdominal wall loses the control and restraint of the abdominal muscles and diaphragm. In the case of a small incisional hernia, the defect in the abdominal wall is compensated by the remaining abdominal muscles and diaphragm. However, the incisional hernia (the volume of the hernia sac) gradually increases with the continuation of the course of the disease under the constant action of thoracic and abdominal pressure. Without effective treatment and control, the incisional hernia may eventually become decompensated, and the abdominal viscera may gradually be displaced out of their original position into the hernia sac. The ratio of hernia sac volume to abdominal cavity volume also changes, which may pose a threat to the body’s respiratory and circulatory systems, a condition known as “large incisional hernia with loss of abdominal domain”. The patient may have the following changes: (1) Respiratory and circulatory system. Due to the large abdominal wall defect, both the abdominal muscles and the diaphragm are limited in their ability to breathe. The outward protrusion of the abdominal hernia causes the diaphragm to move downward, the abdominal viscera to move outward, the intrathoracic pressure to decrease, the lung capacity to decrease, the return blood volume to decrease, and the cardiopulmonary function and reserve function to decrease further. (2) Abdominal organs . Mainly hollow viscera, bowel and bladder are particularly obvious. The herniation and displacement of viscera and the reduction of abdominal pressure will easily dilate the cavity organs and affect their blood circulation and peristalsis, plus the restriction of abdominal muscle function, often causing defecation and urination difficulties. (3) Changes in spine shape As a whole, the barrel-shaped shape of the abdominal cavity plays a role in maintaining the three-dimensional structure and stability of the spine, and the muscles of the anterior abdominal wall play a role like anterior scaffolding for the spine. When the abdominal wall muscles are defective or weak due to incisional hernia, this anterior scaffolding is impaired, which can lead to or aggravate spinal deformity, and patients with large incisional hernias may experience postural changes and spinal pain. In summary, the presence of a large incisional hernia with abdominal wall insufficiency implies a greater risk of surgical repair. Therefore, adequate preoperative evaluation and careful preparation of the patient is required. 3, abdominal wall incisional hernia classification Due to the different incisions, incisional hernia in the occurrence of the site and the size of the defect there are differences, which also caused the difficulty of repair and efficacy of a greater difference. Therefore, the development of an ideal incisional hernia classification method is of great significance in the selection of repair styles and methods, and the evaluation of therapeutic efficacy. However, there is currently no uniform international classification method. According to the classification method of incisional hernia of the European Hernia Society, combined with the clinical reality in China, the classification of incisional hernia should be comprehensively evaluated from the following three aspects. According to the size of the abdominal wall defect classification: (1) small incisional hernia: hernia ring maximum diameter <3cm; (2) medium incisional hernia: hernia ring maximum diameter of 3-5cm; (3) large incisional hernia: hernia ring maximum diameter >5-10cm; (4) huge incisional hernia: the hernia ring maximum diameter of 10cm, or hernia sac volume to abdominal cavity volume ratio >15% (regardless of its hernia ring maximum diameter). According to the hernia defect site classification (1) midline incisional hernia: including subxiphoid incisional hernia, supraumbilical incisional hernia, infraumbilical incisional hernia, suprapubic incisional hernia; (2) lateral abdominal wall incisional hernia: including subcostal incisional hernia, inguinal incisional hernia, and costo-iliac incisional hernia. According to whether the hernia recurrence classification can be divided into incipient incisional hernia and recurrent incisional hernia. 4, diagnosis Typical incisional hernia can be clearly diagnosed through clinical manifestations and physical examination, for small and hidden incisional hernia can be used ultrasound, CT or MRI auxiliary examination. CT or MRI in addition to clearly show the location of the abdominal wall defect, size, hernia content and its relationship with the abdominal organs, can also be used for calculating the volume of the hernia sac and the abdominal cavity, evaluation of the strength and elasticity of the abdominal wall, which is conducive to clinical treatment. 5, treatment of abdominal surgery incisional hernia can not be self-healing, and with the course of the disease and age has a tendency to gradually increase. Therefore, except for contraindications, patients with incisional hernia need to take active treatment. (1) Patients who are not suitable for surgery or who are not suitable for surgery for the time being can use lap band to limit the growth and development of incisional hernia. (2) The incisional hernia that is more than moderate should be repaired with material. (3) The myofascial defect should be closed as much as possible when using material repair. Timing of surgery (1) For patients with incipient incisional hernia and recurrent hernia without infection, it is recommended that repair surgery be performed after the incision has healed and after a period of clinical observation and follow-up. For patients with incisional infection, it is recommended that repair surgery be performed after the infection has been completely cured and the incision has healed, and after a period of observation (at least 3 months or longer). (2) For patients with recurrent hernia who have been repaired with patch material and developed infection, repair should be performed after six months or more of observation after the infection has been cured and the incision has healed. (3) In emergency surgery, patch materials should be used with caution, taking into account the risk of postoperative infection, and absorbable repair materials can be chosen for contaminated wounds. Surgical methods Simple suture repair Suitable for small incisional hernia. Non-absorbable sutures with continuous closure (suture length: incision length 4:1) are preferred. However, there is evidence of a high recurrence rate after 5 years of simple suture repair. Repair with the addition of a patch is indicated in patients with abdominal wall defects of more than a mid-incisional hernia. Depending on the level at which the patch is placed during abdominal wall reconstruction, it can be categorized as: (1) anterior abdominal wall muscle placement (onlay/overlay). (2) Interabdominal wall defect placement (inlay). (3) Posterior abdominal wall muscle (preperitoneal space) placement (sublay). (4) Intraperitoneal placement immediately adjacent to the peritoneum (IPOM/underlay). It is important to emphasize that when this type of repair is used, the patch material should have the property of preventing adhesion, and most of the laparoscopic incisional hernia repairs belong to this type of method. The abdominal wall dilatation and expansion with patch material repair is the tissue structure separation technique (component separationtechnique) with patch to strengthen the abdominal wall method, suitable for the midline or near midline abdominal wall incisional hernia and huge incisional hernia patients. Perioperative management Aggressively manage concomitant systemic illnesses in patients with incisional hernias from abdominal surgery. Closely monitor respiratory function, including routine chest X-ray, pulmonary function and blood gas analysis. For patients with respiratory insufficiency, adequate preoperative preparation should be carried out: for those with lung infection, preoperative antibiotic treatment should be applied, and surgery should be performed 1 week after infection control. The thorax and diaphragm should be calibrated by deep breathing. Smokers should quit smoking 2 weeks before surgery. For large incisional hernias, especially those with a ratio of hernia sac volume to abdominal volume >0.15, abdominal dilatation and abdominal muscle compliance training should be performed preoperatively in order to prevent respiratory failure and abdominal septal compartment syndrome from occurring after the hernia is returned to the abdominal cavity. The hernia can be returned to the abdominal cavity 2-3 weeks before the operation, and the abdominal cavity can be expanded by abdominal banding or progressive artificial pneumoperitoneum. After 2-3 weeks of the above preparatory measures, the patient’s lung function and blood gas analysis results should have improved significantly before surgery. Preoperative prophylactic antibiotics Prophylactic antibiotics can significantly reduce the incidence of incisional hernia infections in abdominal surgery, especially in elderly, diabetic, immunocompromised, large or multiple recurrent incisional hernia, the use of large biomaterials for repair, and incisions that may be subject to gastrointestinal bacterial contamination. Postoperative management (1) Adjust postoperative antibiotics according to experience and bacteriologic monitoring indicators, and the duration should depend on the patient’s condition. (2) Ensure that the closed drainage is airtight and the drainage is smooth, and the removal of the drainage tube should be based on the amount of drainage and the duration of drainage. (3) Wrap the abdomen with a lap band for more than 3 months after surgery to ensure complete healing of the incision. In the early postoperative period, the patient can move around in bed, and can get out of bed after 2-3 d. However, the patient can move around in bed after 3-6 months. However, strenuous activities and heavy labor are prohibited for 3 to 6 months after surgery.