Incisional hernia of the abdominal wall is one of the long-term complications after abdominal surgery, with an incidence of about 2% to 11%, which can increase to 23% if the incision is infected. Currently, there are about 200,000 incisional hernia repairs in the United States in a year, with elderly patients aged >65 years accounting for 39% of the cases. In recent years, with the widespread use of synthetic biomaterials and the popularity of laparoscopic techniques, repair of incisional hernias and reconstruction of the abdominal wall are not too difficult at the purely surgical level. However, surgery on patients with huge incisional hernias is still full of challenges in any hospital and for doctors at all levels, because a large number of intestinal tubes, omentum and other internal organs that have been herniated outside the abdominal cavity for a long time have to be put into the abdominal cavity at once, and the patient may suffer from life-threatening respiratory, circulatory and organ dysfunction after surgery. On the other hand, the larger the incisional hernia, the higher the recurrence rate after surgery, and the literature reports that its postoperative recurrence rate can be in the range of 12% to 54%. Therefore, surgery for giant incisional hernia of the abdominal wall should never be taken lightly. Giant incisional hernia surgery itself may endanger the patient’s life The Hernia and Abdominal Wall Surgery Group of the Chinese Society for Surgery defined a giant incisional hernia as a hernia causing an abdominal wall defect >250px or more. In fact, today this definition does not seem to be strict and comprehensive. We believe that the definition of a giant incisional hernia should not only be a defect of the abdominal wall >250 px, but also the ratio of the volume of the hernia sac to the volume of the abdominal cavity should be defined. In other words, if the hernia contents are fully retracted, whether the patient’s abdominal pressure is altered should be a consideration in the definition of a giant hernia. I have treated some patients with huge incisional hernias, the largest of which was about 500px×750px×1000px. In these patients, the patient’s diaphragm has shifted downward due to the long-term herniation of a large number of organs such as intestines and omentum out of the abdominal cavity, and the original volume of the abdominal domain has decreased due to the huge size of the hernia sac. If the contents of the hernia are simply incorporated into the abdominal cavity without prior preparation, the patient’s diaphragm may be elevated, the intra-abdominal pressure may rise rapidly, the lung volume may decrease, the return blood volume may decrease, the renal blood flow may decrease, and the burden on cardiopulmonary function may increase, resulting in abdominal compartment syndrome (ACS), which is life-threatening. In fact, more than 60 years ago, it was pointed out that “surgery with a large incisional hernia is a potentially fatal procedure that can cause respiratory failure and altered hemodynamics”. In today’s clinical practice, we have indeed seen and managed patients with large incisional hernias who required postoperative ventilatory support in critical cases. Therefore, we emphasize that patients with giant incisional hernia should be given full attention, properly evaluated and carefully prepared, and should not be considered as simple as putting a patch and fixing it with a staple gun. 2. Assessment of the size of incisional hernia and the effect of repair surgery on the patient’s general condition For patients with huge incisional hernia, the true size cannot be accurately and comprehensively determined by physical examination alone. Therefore, imaging techniques such as CT and MRI must be added to show the site and size of the abdominal wall defect and the contents of the hernia sac. It is important to emphasize that since conventional CT and MRI examinations are performed in the supine position, the contents of the hernia can be partially or mostly retracted into the abdominal cavity in most patients with large incisional hernias in the supine position. Therefore, it does not accurately and truly reflect the size of the hernia volume in the daily state. We suggest that CT and MRI examinations of such patients should be performed in the lateral position, which may give a true picture of the hernia volume. In addition to determining the size of the abdominal wall defect (to prepare the appropriate repair material), the ratio of the hernia sac volume to the abdominal cavity volume should be calculated for the analysis of the imaging data; if the ratio is >20%, the patient should be considered to have a large hernia sac and a reduced abdominal volume. Surgery in this group of patients may have systemic effects and a significantly increased incidence of postoperative ACS. Proper preparation is required and surgery should not be rushed. Preoperative preparation of patients with giant incisional hernia with a ratio of hernia sac volume to abdominal cavity volume >20% generally requires abdominal cavity expansion, i.e. artificial pneumoperitoneum. In fact, pneumoperitoneum is an older treatment method, dating back to before the advent of antituberculosis drugs, when it was mainly used to treat tuberculosis and tuberculous peritonitis. As early as 1940, Dr. Goni Moreno introduced the use of oxygen intraperitoneally for the preoperative preparation of patients with large incisional hernias, but the effect of the pneumoperitoneum was reduced by the rapid absorption of oxygen into the abdominal cavity. As a result, improvements have been made, and nowadays, general air is injected, and the method of abdominal expansion with artificial pneumoperitoneum is accepted by more surgeons. The indications for preoperative artificial pneumoperitoneum include: (1) greater difficulty in anticipation of repair, such as multiple and dense adhesions. (2) A significant protrusion of the hernia sac outside the body, the so-called “second abdominal cavity”, where the ratio of the patient’s hernia sac volume to the abdominal cavity volume exceeds 20%. The specific operation of the artificial pneumoperitoneum is as follows: Seldinger’s puncture technique is used, i.e. the needle is inserted into the abdominal cavity and a guiding wire is placed, and then a pigtail catheter (5F) is placed through the guiding outline wire, the puncture site should be far from the anterior abdominal wall of the incision, and after the placement of the tube, air is slowly injected with a 60mL syringe to establish the pneumoperitoneum. When the patient complains of abdominal, subcostal or shoulder pain, with or without mild nausea and soft and flaccid on both sides of the abdominal wall on palpation, the pneumoperitoneum should be stopped 2 to 3 times a week for about 2 weeks. For some difficult patients, a laparoscopic pneumoperitoneum machine can be used to perform pneumoperitoneum in the operating room before surgery. The advantages of artificial pneumoperitoneum are: (1) to expand the volume of the abdominal cavity and reduce the bulging of intra-abdominal organs. (2) Increase the compliance of abdominal muscles. (3) Loosens intra-abdominal adhesions and facilitates intraoperative separation of intestinal tubes and other tissues, reducing operative time and risk. (4) Improved macrovascular function. However, care should also be taken to prevent complications during artificial pneumoperitoneum, including: (1) subcutaneous and retroperitoneal emphysema. (2) Complication of mediastinal emphysema and pneumothorax. (3) Cardiovascular complications. (4) Rare complications such as gallbladder separation, intestinal pneumothorax, etc. These complications are usually temporary and mostly without serious consequences. 4. Respiratory function examination and preparation Respiratory function examination and preparation are very important for patients with giant incisional hernia. It is important to know whether the patient has a history of chronic lung disease and whether there are clinical symptoms such as cough, sputum and wheezing before surgery. Chest X-ray, pulmonary function measurements and arterial blood gas analysis are routinely performed to assess pulmonary ventilation and to determine the presence of occult respiratory insufficiency. For patients with chronic cough and pulmonary infection, mucolytic agents and antibiotics should be administered, and surgery should be performed 1 week after the symptoms improve and the infection is controlled. Smokers should stop smoking at least 2 weeks before surgery, perform thoracic and diaphragmatic exercises, and instruct patients to learn effective deep breathing and abdominal breathing to reduce postoperative respiratory restriction and hypoventilation. For patients with poor respiratory function, preoperative treatment should be performed to achieve the following standards of pulmonary function and blood gas analysis: (1) pulmonary function: spirometry ≥ 80%, residual air volume ≤ 40%. (2) Blood gas analysis: SaO2>93%, PaO2>85mmHg (1 mmHg=0.133kPa), PaCO2 35-45mmHg. Whether the operation can be performed depends partly on the effect of preparation, if the patient’s indexes still do not improve after preparation, the operation is not recommended even if the patient strongly requests it. For patients who are too old and frail to tolerate artificial pneumoperitoneum, we use a lap band with pressure to improve the patient’s thoracic breathing capacity. According to the size of the patient’s hernia defect, a wide multi-headed lap band is made and the abdomen is gradually wrapped with pressure as tolerated by the patient until all hernia contents are returned and maintained for more than 1 week. This method is noninvasive and simple to perform, but has the disadvantage of not increasing the abdominal volume significantly. After the hernia contents are returned, the patient can be operated after the lung function and blood gas analysis indexes reach the standard, otherwise the operation should be abandoned. 5. Prophylactic antibiotic application At present, most scholars at home and abroad advocate the prophylactic application of antibiotics before incisional hernia surgery, and a large number of clinical studies have shown that the application of prophylactic antibiotics can significantly reduce the infection rate of incisional hernia in abdominal surgery, especially in the elderly, diabetic, immunocompromised, huge or recurrent incisional hernia and those who use large biomaterials for repair, and it is more necessary for those whose incisions may suffer from gastrointestinal bacterial contamination [10]. The procedure is usually performed 45 min before surgery. It is usually given intravenously 45 min before surgery and does not need to be given more than one day in advance, but antibiotics should be administered to those with preoperative lung or incisional hernia site infections until the infection is controlled before surgery. 6. Timing and principles of surgery Incisional hernia cannot heal by itself, and all need surgery. For patients with poor general condition and medical comorbidities such as cardiopulmonary insufficiency, the appropriate timing of surgery should be selected after active preoperative preparation. For incisional hernia and recurrent hernia without a history of infection, repair is usually possible 3 to 6 months after the incision has healed. For recurrent incisional hernia caused by infection after repair with artificial material, bacterial culture should be taken from the subcutaneous tissue of the recurrence before reoperation. For small and medium incisional hernias with traumatic contamination, direct suture repair or autologous tissue graft repair is preferred, and if the defect is large, autologous tissue graft or absorbable biomaterials can be used for repair. If the contamination is not heavy, under good surgical technique, large-space mesh polypropylene patches can also be used for repair, and Teflon and its composite materials are generally not suitable for repair.