Parastomal Hernias

A s soon as a stoma is constructed, a potential site of weakness in the abdominal wall is instantly produced. Parastomal hernia occurs when weakness in the abdominal wall is sufficient to permit abdominal contents, usually the intestine, to protrude through the fascial defect around the stoma and into the subcutaneous tissue, creating a bulge on the abdomen. Parastomal herniation occurs in approximately 30% of all stomas¹ and is more common in colostomies than in ileostomies and urostomies.

Peristomal herniation has been attributed to many causes: 1) placement of the stoma outside the rectus sheath, 2) an oversized defect created in the abdominal wall through which the stoma protrudes, 3) increased intra-abdominal pressure, 4) location of the stoma in a midline incision, 5) wound infection at the mucocutaneous border, or 6) poor abdominal muscle tone due to aging and weight gain or loss.² The progress of a parastomal hernia is often gradual as the area next to the stoma stretches and becomes weaker over time. Every strain (coughing, laughing) or other increase in intra-abdominal pressure (with heavy lifting or strenuous abdominal exercise) causes the area around the stoma to bulge and/or the entire stoma to protrude as it is pushed forward by the intestine behind it.

An analysis of the United Ostomy Association's data registry of 16,470 patients³ found that hernia was the most common complication for patients with stomas located outside the rectus sheath. A small study in Europe found that the placement of the stoma on the abdomen did not influence the rate of para-colostomy hernia.⁴ Traditional practice, however, seems to support stomal placement through the rectus sheath as an optimal measure to prevent parastomal hernia formation.

As time passes, the size of a hernia will likely increase. These hernias are rarely painful but can be uncomfortable and cause embarrassment if they are large enough to be seen through clothing. Because the uneven abdominal contours around the stoma created by the hernia fluctuate as the hernia alternately protrudes and reduces in response to body movement or changes in intra-abdominal pressure, parastomal hernias can cause serious management problems that result in leakage, skin irritation, and shortened wear time.

Over the years, many surgical approaches to hernia repair have been implemented with the goal of making the abdominal wall tissue fit snugly around the stoma, leaving no weaknesses. Even though this may seem to be the simplest and most logical intervention, it is not always successful. Today, three techniques are currently used for repairing a parastomal hernia:¹ 1) localized fascial repair, 2) localized fascial repair with mesh, and 3) relocation of the stoma. Surgical options for treating primary large symptomatic parastomal hernias include local repair with mesh implantation and stomal relocation. Stomal relocation is a major surgery with laparotomy and necessitates moving the stoma to another site on the abdomen and repairing the hernia at the old site. Recurrent hernias are best treated by local repair with mesh implantation. The use of mesh over and beyond the weakened area reinforces the weakened muscle structure and spreads the mechanical load over a larger area. Controversy exists regarding which procedure should be used at what point in the progression of the hernia. Some clinicians believe that for first presentation parastomal hernias relocation should be the treatment and that recurrent hernias should be repaired with implantation of mesh.¹

Because of the high recurrence rates, small hernias that are not symptomatic or hernias in patients who are not surgical candidates are best managed conservatively. Such management consists of observation, the use of a hernia support belt designed to fit around the pouch and provide support to the abdominal wall, and ongoing patient education. The support belt should be applied with the patient in a recumbent position while the hernia is reduced. By virtue of their rigidity, some convex products pose the potential for pressure-related skin or stomal damage for a patient with a parastomal hernia. They should, therefore, be used with caution. Patients may be better served with flexible, low profile, or newer flangeless pouching systems worn under the hernia support belt.

With quality of life such a pivotal issue in today's healthcare environment, serious consideration should be given to the management of parastomal hernias. Nurses caring for stoma patients should instruct not only at-risk patients (those with colostomies, poorly sited stomas, weight gain, or poor abdominal muscle tone) but also all stoma patients on proper steps they can take to prevent the development of and progressive enlargement of a parastomal hernia. A new generation of flangeless pouching systems may assist in reducing leakage and preventing skin irritation as well as improve patient comfort for patients with parastomal hernias.

The development of a parastomal hernia creates multiple quality-of-life issues for the patient and consumes valuable healthcare resources. Patient education plays a critical role in preventing the progression of a parastomal hernia and conservative management of a small asymptomatic one. - OWM