A pilonidal sinus is a small tract present in or near the natal cleft at the top of the buttocks. They commonly form around a dilated hair follicle into which hairs, desquamated skin, and other debris become entrapped leading to secondary infection (the pit is the primary cause).
There are two traditional methods for excising the pilonidal sinuses and two for closing the wound. Regarding the excision the first is a midline approach, the second off-midline. When closing the wound following the excision of pilonidal sinuses one method is to leave the wound open (therefore allowing healing through secondary intention), the second method is for primary closure. Risks involved have been structured around the categories mentioned here, however, within these categories there are a number of different surgical procedures for which individual risks have not been given.
Rhomboid flap: the sinus tracts are excised and a rhomboid flap is transposed to cover the defect.
V-Y advancement flap: in this technique a V incision is made, this is then approached to cover the defective as a Y shape.
Bascom procedure: lateral (or off-line) incision to access the pilonidal cavity followed by curettage. The midline pits are then excised separately. The midline incisions are closed, the lateral incisions is left open.
Karydakis procedure: A midline elliptical incision of the sinus down to the sacrum. A flap is then created by undercutting the midline side of the wound and advanced across the wound to the opposite side and sutured in place. The skin is then closed.
Marsupialization: the sinus is incised; the borders are raised and stitched to form a pouch. This gradually loses and may need to be packed until this has happened.