A parastomal hernia (PSH) is a type of incisional hernia that occurs at the site of the stoma or immediately adjacent to the stoma (image 1). It forms when the abdominal wall defect, the trephine, is continually stretched by the tangential forces applied along the circumference of the abdominal wall opening .
The construction of an ostomy and the management of patients with an ileostomy or colostomy are reviewed separately. (See "Surgical principles of ostomy construction" and "Management of patients with a colostomy or ileostomy".)
A parastomal hernia (PSH) is the most frequent complication following the construction of a colostomy or an ileostomy. It has even been suggested that a certain degree of PSH is almost inevitable .
The reported incidence varies widely and is related to a number of factors including: the lack of a standard definition, type of ostomy constructed, and variability in the duration of follow-up after ostomy construction [3-13]. A minor degree of parastomal weakness is present in many patients and does not represent a true hernia .
A review found that PSH occurs in 1.8 to 28.3 percent of patients with end-ileostomy, 0 to 6.2 percent with loop ileostomy, 4.0 to 48.1 percent with end-colostomy, and 0 to 30.8 percent with loop colostomies . The lower rate for loop ostomy is related to the temporary nature of most of these stomas and the short duration of follow-up. Most parastomal hernias occur within the first two years of construction, and studies with longer follow-up report higher PSH rates .