The Hernia and Abdominal Wall Surgery Group of the Chinese Medical Association and the Hernia and Abdominal Wall Surgery Committee of the Chinese Association of Physicians and Surgeons have different affiliations, but they share the same goal, which is to improve the diagnosis and treatment level of hernia and abdominal wall surgery in China. To this end, the two groups collaborated with each other to prepare the Guidelines on Inguinal Hernia Diagnosis and Treatment for Adults in 2013, and then organized a revision and joint discussion in the beginning of 2014 to complete the Guidelines. It should be noted that the predecessor of the “Guidelines” is “Guidelines for the diagnosis and treatment of inguinal hernia in adults (2012 edition)”, and this revision is based on the progress of relevant disciplines at home and abroad in recent years and China’s national conditions, and added some provisions, with the aim of emphasizing the specialization and standardization of inguinal hernia surgical treatment, and to improve the level of treatment of hernia surgery in China. 1, the definition of inguinal hernia inguinal hernia refers to the occurrence of extra-abdominal hernia in the inguinal region, that is, in the inguinal region of the abdominal wall defect, there is a hernia sac protruding to the body surface of the structure, the abdominal organs or tissues can be formed through the congenital or acquired abdominal wall defects into the hernia sac. A typical inguinal hernia has a hernia ring, a hernia sac, hernia contents, and a hernia cover. According to the anatomical concept of “musculopubic foramen”, inguinal hernia includes hiatal hernia, straight hernia, femoral hernia, and the rare anterior and lateral femoral vascular hernia. 2, the etiology and pathophysiology of inguinal hernia 2.1 etiology (1) sheath not closed: for inguinal hernia occurrence of congenital factors. (2) Intra-abdominal pressure: intra-abdominal pressure and instantaneous intra-abdominal pressure changes are the driving force for the occurrence of extra-abdominal hernia. (3) Localized weakness of the abdominal wall: various causes of weakness of the abdominal wall in the inguinal region due to alterations in the metabolism or composition of the collagen of the tissue are associated with the development of inguinal hernia. (4) Others: genetic factors, long-term smoking, obesity, and low incisions in the lower abdomen may be associated with the development of inguinal hernia. 2.2 Pathophysiology When the organs or tissues in the abdominal cavity enter the hernia sac, due to the presence of the hernia ring, the hernia contents can be compressed, forming an incarcerated hernia. If the content is intestinal tube, it can cause mechanical obstruction of intestinal tube and produce a series of clinical manifestations and pathophysiological changes. With the prolongation of the pressure time, the intestinal tube appeared edema, oozing and the embedded intestinal tube blood flow obstruction, if not treated in time, can lead to necrosis of hernia content, perforation, and then serious peritonitis, or even life-threatening. 3.Classification and typing of inguinal hernia The purpose of classification and typing of inguinal hernia includes: ①accurately describe the condition; ②choose the appropriate treatment plan; ③comparison and evaluation of the therapeutic effect of different methods. 3.1 Classification 3.1.1 Classification according to the anatomical site where hernia occurs Inguinal hernia can be classified into hiatal hernia, straight hernia, femoral hernia, composite hernia and so on. (1) Hiatal hernia: a hernia that enters the inguinal canal from the internal ring. (2) Straight hernia: hernia protruding from the triangle of straight hernia. (3) Femoral hernia: a hernia that enters the femoral canal through the femoral ring. (4) Compound hernia: hernia in which two or more of the above types are present at the same time. (5) Perivascular femoral hernia: hernia located anteriorly or laterally in the femoral vessels, which is clinically rare. 3.1.2 Classification according to the status of the hernia contents into the hernia sac (1) easy to recurring hernia: hernia often appears when standing or activity, after lying down and resting or pushing with the hand can be returned to the abdominal cavity. (2) Refractory hernia: the hernia can not be completely retracted, but the contents of the hernia have not undergone organic pathological changes. Sliding hernia is a type of refractory hernia because part of the hernia sac is made up of abdominal viscera (e.g., cecum). (3) Incarcerated hernia: the hernia contents are compressed at the hernia ring and cannot be returned. Certain clinical symptoms (e.g., abdominal pain and signs of gastrointestinal obstruction) may be present, but hemodynamic disorders have not yet occurred. (4) strangulated hernia: the continuation of the incarcerated hernia course, the hernia content has developed blood transportation obstruction, if not treated in time, serious complications may occur, even life-threatening due to intestinal perforation and peritonitis. 3.1.3 Special types of hernia The contents entering the hernia sac are relatively special and have a certain impact on the development and treatment of the disease, including the following types. (1)Richter’s hernia: the contents of the incarcerated hernia are only part of the intestinal wall, and even though incarceration or strangulation occurs, there may be no clinical manifestation of intestinal obstruction. (2) Littre’s hernia: the content of the incarcerated hernia is a small bowel diverticulum (usually Meckel’s diverticulum). This type of hernia is prone to strangulation. (3) Maydll hernia: a retrograde incarcerated hernia in which two or more bowel loops enter the hernia sac, with the intervening bowel loops remaining in the abdominal cavity in the shape of a “W”. The bowel loops located in the hernia sac may be normalized in terms of hemodynamics, but bowel loops located in the abdominal cavity may be necrotic, and a thorough examination is required. (4) Amyand’s hernia: the hernia is composed of the appendix, which is often complicated by inflammation, necrosis, and suppuration that interfere with repair. 3.2 Typing On the basis of hernia classification, hernia conditions are more carefully divided. At present, there are more than ten types of inguinal hernia classification at home and abroad, but there is still a lack of clinical evidence on the appropriateness of the criteria. Therefore, the existing classification system is still imperfect and has a certain subjective color. At this stage, CHARTS, Nyhus, Bendavid, Stoppa, EHS and other typing systems are still in use, and it is believed in this revision that the existing typing systems can be referred to, but not recommended as a standard. 4, inguinal hernia diagnosis and differential diagnosis 4.1 Diagnosis Typical inguinal hernia can be based on history, symptoms and physical examination to establish a diagnosis. If the diagnosis is unclear and difficult, imaging studies such as B-mode ultrasound, MRI and/or CT may be used to help establish the diagnosis. Hernia sac reconstruction techniques in imaging can often lead to a definitive diagnosis of inguinal hernia. 4.2 Differential diagnosis It is recommended that when a diagnosis of inguinal hernia is made, a differential diagnosis should also be routinely made, taking into account all factors, to prevent the occurrence of herniorrhaphy in non-herniated patients. (1) Diseases that need to be differentiated when there is a mass in the inguinal region include large lymph nodes, arteriosarcoma, soft tissue tumors, abscesses, ectopic testes, round ligament cysts, and endometriosis. (2) For local pain and discomfort symptoms need to identify the disease: including adductor muscle tendonitis, pubic osteochondritis dissecans, hip arthritis, iliopubic bursitis, radiating low back pain, endometriosis, etc.. 5, inguinal hernia treatment clinically almost all inguinal hernia through surgery and get cured, at present the domestic medical market there are still some non-surgical treatment methods, such as “hernia local injection” and other non-surgical treatments, not only does not accord with the scientific principle, but also can bring a series of complications and adverse reactions to the patient, should be discarded. In terms of surgical methods and approaches, surgeons should choose according to the patient’s condition and their own skills. 5.1 Treatment Principles and Indications for Surgery (1) Asymptomatic inguinal hernia can be followed up and observed or treated with elective surgery according to the evidence of evidence-based medicine. In case of femoral hernia (timely surgical treatment is recommended because of higher probability of incarceration and strangulation or recent discovery of significant hernia sac enlargement). For those who cannot tolerate surgery due to old age and infirmity, etc., hernia tray can also be chosen for conservative treatment. (2) Symptomatic inguinal hernia should be selected for elective surgery. (3) Emergency surgery should be performed for incarcerated and strangulated hernias. (4) Surgical treatment of recurrent hernia: avoidance of anatomical difficulties caused by trauma from previous surgery is a consideration (e.g., if the previous surgery was a conventional open surgery, the recurrence should be repaired by posterior access or laparoscopic surgery for reoperation). In addition, the qualification and experience of the physician is a factor to be considered when choosing a treatment modality for recurrent hernia. 5.2 Surgical contraindications and precautions (1) Inguinal hernia in a non-emergency setting is a sterile procedure; therefore, the presence of an infected lesion in the surgical area should be considered a surgical contraindication. (2) Relative contraindications and precautions: the presence of factors that cause increased intra-abdominal pressure, such as severe ascites, prostatic hypertrophy, constipation and chronic cough, etc., need to be treated accordingly before surgery to minimize the occurrence of complications such as early postoperative recurrence. (3) A multidisciplinary treatment model is recommended for patients with large abdominal wall defects and large hernia sac cavities. Multidisciplinary consultation with plastic surgery, respiratory medicine and intensive care department is invited to participate and formulate the surgical plan to prevent the occurrence of abdominal compartment syndrome. (4) Surgical risk assessment, recommended to use the American Society of Anesthesiologists surgical risk assessment standards. 5.3 Qualification and training of surgeons (1) Routine inguinal hernia repair is not a “simple minor surgery” and should be performed by a surgeon who is licensed to practice medicine and has completed a residency and appropriate surgical training. (2) Physicians performing laparoscopic hernia repair are required to complete, pass, and be certified in the appropriate laparoscopic skills in addition to the above. (3) Training of hernia and abdominal wall surgeons: to be completed in training centers with appropriate qualifications (according to the relevant regulations of the Chinese Medical Association or the Chinese Medical Doctor’s Association). 5.4 Inguinal hernia repair materials Tension-free hernia repair using repair materials is currently the mainstay of surgical treatment. There is medical evidence that surgery using repair materials reduces postoperative pain, shortens recovery time, and decreases hernia recurrence rates. (1) Hernia repair materials are categorized as absorbable, partially absorbable and non-absorbable materials. (2) The implantation of the repair material should be strictly carried out in aseptic principle. The use of materials is not recommended for emergency surgery for incarcerated hernia, and the use of non-absorbable materials for repair is not recommended for surgery with the possibility of contamination. 5.5 Surgical operation methods Surgical treatment of inguinal hernia can be divided into two categories: conventional surgery and lumpectomy. (1) Conventional surgery can be further divided into tissue-to-tissue tension suture repair (also known as classical surgery), such as the Bassini and Shouldice procedures, and tension-free hernia repair using hernia repair materials. Tension-free hernia repairs include those that reinforce the posterior inguinal wall, such as plain sheet repairs (Lichtenstein, Trabucco, etc.) and mesh plug-plain sheet repairs (e.g., Rutkow, Millikan, etc.), as well as tension-free hernia repairs targeting the anterior peritoneal space of the “myopubic foramen”, such as Kugel, Gugel, Gugel, Gugel, Gugel, Gugel, and others. (2) Laparoscopic hernia repair: Kugel, Gilbert, Stoppa, etc.). (2) Laparoscopic inguinal hernia repair is divided into the following three categories according to the surgical route and principle: ① Transperitoneal extraperitoneal route repair (TEP), which does not enter the abdominal cavity and has the advantage of less interference with the abdominal cavity. Transperitoneal preperitoneal repair (TAPP), because it enters the abdominal cavity, it is easier to find bilateral hernias, composite hernias and hidden hernias. For incarcerated hernia and hernia content is not easy to return the case, but also easy to observe and deal with. (iii) Intraperitoneal patch repair (IPOM), used when the above two methods are difficult, is not recommended as the preferred method of laparoscopic surgery. When repairing by this method, the repair material should be anti-adhesion material. 5.6 Perioperative treatment (1) General treatment: ① In addition to the routine preoperative examination, elderly patients should be informed of and examined for cardiac, pulmonary, renal function and blood glucose level. ② Elderly patients with chronic medical diseases should be evaluated for their risk before surgery, especially for patients with respiratory and circulatory diseases, which need to be treated and dealt with before surgery. (2) Regarding the use of antibiotics: there is debate as to whether antimicrobials should be routinely applied prophylactically in inguinal hernia surgery. There is evidence that prophylactic application of antibiotics to high-risk groups can reduce the probability of infection. ①High-risk factors: including advanced age, diabetes, obesity, emaciation, multiple recurrent hernias, post-chemotherapy or radiotherapy and other immunocompromised conditions. ② Timing of prophylactic antibiotic application: it is recommended to start intravenous administration 30min to 1h before skin incision. 5.7 Complications (1) Early complications: hematoma and seroma at the surgical site, scrotal hematoma, scrotal effusion, bladder injury, vas deferens injury, urinary retention, early wound pain, and incision infection. (2) Late complications: chronic pain, spermatic cord and testicular complications (ischemic orchitis, testicular atrophy, etc.), delayed patch infection, patch migration, etc. (3) Recurrence: The various surgical methods currently available for the treatment of inguinal hernia still have the possibility of recurrence, and the overall surgical recurrence rate is 1% – 3%. The causes of hernia recurrence can be summarized in two aspects: surgical operation and patients themselves: such as incomplete separation of the hernia sac during the operation, improper fixation of the patch, postoperative hematoma, infection and so on are the factors of recurrence; patients with collagen metabolism disorders, chronic metabolic diseases and increased intra-abdominal pressure are also the factors of recurrence.