1. Hemorrhoids, or hemorrhoids, are the most common anal diseases in clinic. In 1975, Thomson, an Englishman, put forward a modern concept of hemorrhoids [1]: Hemorrhoids are pathological hypertrophy of the anal cushion at the lower end of the rectum. According to the location, hemorrhoids can be divided into internal hemorrhoids, external hemorrhoids and mixed hemorrhoids.
2. At present, it is considered that Internal hemorrhoid is the pathological change or displacement of the supporting structure, vascular plexus and arteriovenous anastomosis branch of anal pad. External hemorrhoid is pathological dilation or thrombosis of subcutaneous vascular plexus distal to dentate line. Mixed hemorrhoid is a mixture of internal hemorrhoids and external hemorrhoids.
theory of varicose veins: venous plexus is the main structure to form anal cushion, and the formation of hemorrhoids is inevitably related to the pathological expansion and thrombosis of venous plexus. Anatomically, there is no venous valve in portal vein system and its branch rectal vein; The upper and lower rectal venous plexus is thin and shallow; The submucosal tissue of the terminal rectum is slack, and these factors can easily lead to blood stasis and venous dilatation. In addition, because the anorectal canal is located in the lowest part of abdominal cavity, many factors, such as long-term sitting, constipation, pregnancy, prostatic hypertrophy, pelvic giant tumor, etc., can all cause obstruction of rectal venous return. It is quite controversial at present.
Fourth, the theory that the anal cushion moves downwards: the anal cushion can close the anal canal and control defecation. Under normal circumstances, the anal pad is loosely attached to the anal canal muscle wall; When defecating, it is pushed downward by downward pressure, and then it retracts into the anal canal with the help of its own contraction. After the elastic retraction ability is weakened, the anal pad is congested and moves down to form hemorrhoids. The mainstream of western medicine supports the theory of anal cushion moving down.
5. Clinically, it is commonly called PPH (Procedure for Prolapse and Hemorrhoids) operation, which is mainly used to treat patients with Ⅲ and Ⅳ degree internal hemorrhoids, Ⅱ degree internal hemorrhoids and annular hemorrhoids who have failed in non-surgical treatment, and can also be used to treat patients with rectal mucosal prolapse. Its principle is to use a specially designed stapler to circularly remove the rectal mucosa 2-4cm away from the dentate line, so that the downward anal pad can be moved up and fixed to achieve the therapeutic purpose. It is characterized by high equipment cost.