Parastomal Hernia

Parastomal hernia is an incisional hernia created by making a defect in the abdominal wall during stoma creation (Figure 1).[1] The development of parastomal hernias depends on patient factors, the type of stoma, and the technique used to construct the stoma. The incidence is estimated to be 1.8%–28.3% for end ileostomies, 0%–6.2% for loop ileostomies, 4%–48% for end colostomies, and 0%–30.8% for loop colostomies.[2][3] Studies with long follow-up have shown the hernia rate after colostomy creation to be more than 50%.[4] Risk factors include advanced age, obesity, wound infection, increased intraabdominal pressure, chronic obstructive pulmonary disease, inflammatory bowel disease, malignancy, and use of steroids.[3][5][6] The technique used to construct the stoma has been shown to affect the rate of hernia. Emergency surgery, poor site selection, surgical approach (i.e., open vs laparoscopic) abdominal wall strength, and the size of the fascial aperture increase the risk. One study with mean follow-up of 26 months demonstrated that no patient with an abdominal wall aperture diameter ≤25 mm developed a parastomal hernia.[7]

Figure 1. Parastomal hernia

Patients with parastomal hernias may present with minimal or no symptoms or may present with a range of symptoms such as mild peristomal discomfort, difficulty in maintaining the stoma appliance, dermatitis, stoma prolapse, cosmetic disfigurement, bowel obstruction, and strangulation. These symptoms may impact patient quality of life.

Extraperitoneal tunneling,[8] stoma-fascia fixation, stapled ostomy creation,[9] and prophylactic mesh reinforcement[10] have been described as means to prevent parastomal hernias. Extraperitoneal tunneling is associated with lower rate of parastomal hernias but increased operative times and rate of complications. Data showing decreased incidence of parastomal hernias after prophylactic mesh placement using either biologic or synthetic mesh in a preperitoneal or sublay position have been inconclusive.[11][12] A meta-analysis of randomized trials showed that the rate of parastomal hernias was significantly decreased with prophylactic mesh placement. This significance was not sustained when only studies conducted in the past 5 years were analyzed (p = 0.10).[13] A multicenter, randomized, double-blind trial showed that there was no significant difference in parastomal hernia rates at 3-year follow-up when comparing patients with and without prophylactic mesh.[14]

Most patients with parastomal hernias can be managed conservatively by enterostomal nurses and with the use of stoma belts and optimization of stoma appliances. Leas than 20% of patients will require parastomal hernia repair.[2] All surgical approaches have a risk of recurrence. Local suture repair is simple in design but has >70% recurrence rate.[15][16][17] Relocation of the stoma has a significant combined risk of recurrent hernia at the original site, hernia at the new stoma site, and hernia at the laparotomy/laparoscopy site, with rates in the 24%–86% range.[15] Intraabdominal repair with mesh (Sugarbaker or keyhole, performed as an open or minimally invasive approach) is the most commonly used technique with recurrence rates of 2%–16%.[18] Hernia contents are reduced back into the abdominal cavity, and mesh is placed anterior to the rectus or external oblique fascia (onlay) or below the fascia and muscular layers (preperitoneal or sublay technique). Laparoscopic, robotic, and open approaches have been described.[19] Synthetic prosthetic mesh materials include polypropylene, polyester, or expanded polytetrafluoroethylene (ePTFE). Composite mesh has been specifically designed to be used in parastomal hernia repairs with a 3% complication rate.[20] Biologic mesh has similar complication rates compared with prosthetic mesh with increased risk of recurrence and significantly increased cost.[21]