A parastomal hernia (PH) is defined as the herniation of any abdominal cavity content other than the ostomy itself through the ostomy orifice. It should be distinguished, however, from mucosal prolapse, which is a full-thickness protrusion of intestine through the stoma.
Parastomal hernias are a fairly common complication in patients with a definitive stoma, being observed in 30-50% of them. Thus they are more frequent overall than incisional ventral hernias. Most parastomal hernias occur within the first years after their stoma is created, but may arise much later, as the patients grow older and the abdominal wall may become weaker.
Parastomal hernias occur as a result of weakness in the abdominal wall which may or may not be associated with elevated intraabdominal pressure, or be due to a technical failure when the stoma is created.
Consequently, the main risk factors for parastomal hernias are:
- – Advanced age
- – Obesity
- – Malnutrition
- – Steroid use or other immunodeficience
- – Smoking and/or COPD
- – Wound infection
The diagnosis is established on the basis of clinical history and physical examination. The most frequent complaints are discomfort and difficulty in adapting ostomy appliances. The physical examination will show a bulge under the skin beside the ostomy, which is increased by
Valsalva’s maneuver and may be completely or partially reducible. In obese patients, the diagnosis of parastomal hernias by physical examination may be difficult. In these cases, when there is a complaint, a CT scan or ultrasound can be helpful for diagnosis. Moreover, these exams are helpful in evaluating the size of the hernia, as well as its contents.
Several classifications have been created over the years, until in 2014, the European Hernia Society created a consensus classification in order to improve the ability to compare different studies and their results, in addition to facilitating data collection.
The classification divides hernias into four types and distinguishes between primary and recurrent hernias. Hernias are rated according to size (≤ or > 5 cm) and presence or not of incisional hernia (cIH).
- – Type I: PH ≤5 cm with no cIH.
- – Type II: PH ≤5 cm with cIH.
- – Type III: PH >5 cm with no cIH.
- – Type IV: PH >5 cm with cIH.
- – P: primary PH.
- – R: recurrence after previous PH treatment.
There is no consensus on the timing of elective surgical treatment for parastomal hernias. Treatment should be tailored according to the patient’s symptoms and complaints and should take into consideration the patient’s comorbidities, quality of life and clinical status, as well as the risk associated with watchful waiting. The main symptoms leading to surgery are discomfort, pain, bowel obstruction and/or strangulation, and difficulty in proper fixation of ostomy appliances, leading to peristomal dermatitis and physical deformity. There are some clinical measures that can be taken to minimize symptoms, such as use of support garments, losing weight and follow-up with stomal nurses.
Many techniques have been proposed, from Sugarbaker to repositioning of the colostomy, open vs laparoscopic, biological or synthetic mesh vs no mesh. One of the most frequently employed techniques is the Sugarbaker technique, which consists of applying an intraperitoneal mesh covering the ostomy.
There are some intra and post-operative measures that can help to prevent the development of parastomal hernias, such as:
- – Correct positioning, placing the orifice through the rectus muscle
- – Avoiding excessive opening of the fascia (as small as possible, as long as it doesn’t compromise stoma perfusion)
- – Wearing a support garment (belt or underwear)
- – Avoiding heavy lifting and straining
- – Avoiding being overweight and maintaining a normal body mass index when possible – being overweight can place additional strain on your abdominal muscles.