Pilonidal sinus is a very common disease of the buttock region which mostly affects young adults (men more than women) and for many with the disease, the condition can be painful and long-lasting (chronic). The disease is thought to arise from ingrowing hair between the buttocks, which then becomes infected and forms into a "sinus" or tract. Patients with a pilonidal sinus usually present to their doctor with painful swelling around the buttock area, which may discharge pus-like substance. This disease is usually treated by surgery. Surgeons agree that the area where the infection has developed should be completely incised and removed. However, surgeons have not agreed whether the resulting wound should be stitched closed or left open to heal without stitches. This review of the published literature found that patients who had their wounds closed with stitches healed faster and returned to work earlier than patients whose wounds were left unstitched and allowed to heal "naturally". However, the review also found that patients who had their wounds closed with stitches were more likely to get the disease again compared to those who did not have their wounds closed by stitches. This means that each type of surgical treatment has its advantages and disadvantages, and that the decision about which type of surgical wound to select should also be guided by the patient's own desired goals for treatment. The review also found that if a decision had been made to close the wound with stitches, then the best way to reduce the risk of the disease coming back and reduce other complications (such as infection), was to use a wound technique where the line of stitches was moved away from between the buttocks. Therefore one definitive recommendation from this systematic review is that where a decision has been made to close the sinus wound using stitches, this wound should not lie in the central area of the buttocks.