trusses, trunks, belts, etc.) are unclear. Surgery Surgery is recommended for some types of hernias to prevent complications such as obstruction of the bowel or strangulation of the tissue, although umbilical hernias and hiatus hernias may be watched, or are treated with medication. Most abdominal hernias can be surgically repaired, but surgery has complications. Time needed for recovery after treatment is reduced if hernias are operated on laparoscopically. However, open surgery can be done sometimes without general anesthesia. Robot-assisted hernia surgery has also recently gained popularity as safe alternatives to open surgery. Uncomplicated hernias are principally repaired by pushing back, or "reducing", the herniated tissue, and then mending the weakness in muscle tissue (an operation called herniorrhaphy). If complications have occurred, the surgeon will check the viability of the herniated organ and remove part of it if necessary. Muscle reinforcement techniques often involve synthetic materials (a mesh prosthesis). The mesh is placed either over the defect (anterior repair) or under the defect (posterior repair). At times staples are used to keep the mesh in place. These mesh repair methods are often called "tension free" repairs because, unlike some suture methods (e.g., Shouldice), muscle is not pulled together under tension. However, this widely used terminology is misleading, as there are many tension-free suture methods that do not use mesh (e.g., Desarda, Guarnieri, Lipton-Estrin, etc.). Evidence suggests that tension-free methods (with or without mesh) often have lower percentage of recurrences and the fastest recovery period compared to tension suture methods. However, among other possible complications, prosthetic mesh usage seems to have a higher incidence of chronic pain and can also cause infections. The frequency of surgical correction ranges from 10 per 100,000 (U.K.) to 28 per 100,000 (U.S.). Recovery Many patients are managed through day surgery centers and are able to return to work within a week or two, though intense activities are prohibited for a longer period. People who have their hernias repaired with mesh often recover within a month, but pain can last longer. Surgical complications may include pain that lasts more than three months, surgical site infections, nerve and blood vessel injuries, injury to nearby organs, and hernia recurrence. Pain that lasts more than three months occurs in about 10% of people following hernia repair. Epidemiology About 27% of males and 3% of females develop a groin hernia at some time in their lives. In 2013 about 25 million