An incisional hernia is a specific type of hernia that develops at the site of a previous surgical incision. This condition occurs when an organ or fatty tissue pushes through a weak spot in the surrounding muscle or connective tissue, often creating a visible bulge. It is a common complication following abdominal operations. Recognizing how this condition presents itself is important for timely evaluation and management.
What is an Incisional Hernia?
An incisional hernia forms when the layers of the abdominal wall, cut during a prior surgery, fail to heal completely or develop a structural weakness. The defect occurs in the fascia, the strong connective tissue layer that holds the muscles together. This failure allows pressure from inside the abdomen to push tissue outward through the weakened area.
The resulting protrusion is always located at or immediately adjacent to a surgical scar. The hernia sac typically contains abdominal fat, a portion of the omentum, or a loop of the intestine. While the condition can occur at any time, the highest susceptibility is generally three to six months following the original operation.
The incidence of this complication is relatively high, occurring in up to 20% of patients who undergo abdominal surgery involving an incision. Increased intra-abdominal pressure, such as from coughing or straining, forces the contents through the defect due to the reduced strength of the surgically repaired wall.
Common Signs and Discomfort
The most frequently noticed sign of an incisional hernia is a soft, visible bulge or lump near the surgical scar. This swelling becomes more pronounced when abdominal pressure is raised, such as when standing upright, coughing, or lifting heavy objects. The bulge often reduces in size or disappears entirely when a person lies down, as the internal contents fall back into the abdominal cavity.
Many people experience discomfort ranging from mild to moderate. A dull aching sensation is common, particularly after physical activity or prolonged standing. Other symptoms include a feeling of heaviness, pressure, or a persistent pulling sensation at the incision site, which may also feel mildly tender.
The ability of the hernia to be gently pushed back into the abdomen is known as reducibility, defining a non-complicated case. Discomfort and pain worsen with movements that strain the abdominal muscles. These symptoms usually indicate a stable hernia that can be addressed electively.
Factors That Increase Risk
The development of an incisional hernia is determined by factors affecting the body’s ability to heal and those that increase pressure on the surgical site. A major predisposing factor is a post-operative wound infection, which impairs the proper formation of strong scar tissue in the fascia. This infection can increase the risk of an incisional hernia by 70%.
Several conditions and behaviors compromise the body’s healing environment and increase the likelihood of developing this hernia type:
- A Body Mass Index (BMI) greater than 25, which causes excessive abdominal pressure.
- Chronic health issues, including diabetes mellitus and kidney failure.
- Use of certain medications, such as steroids or immunosuppressants.
- Smoking, as nicotine impairs collagen synthesis necessary for strong connective tissue.
- Activities that create excessive strain on the healing abdominal wall, such as heavy lifting, persistent coughing, or constipation.
- The nature of the original surgery, with emergency procedures and midline incisions carrying a greater inherent risk.
Warning Signs of Complications
While many incisional hernias remain stable, a sudden change in symptoms signals a medical complication requiring immediate attention. The most significant warning sign is the sudden onset of severe pain at the hernia site. This intense pain often indicates that the herniated tissue is trapped, a condition called incarceration.
A trapped hernia that cannot be gently pushed back into the abdomen is irreducible and can quickly progress to an emergency. If the blood supply to the incarcerated tissue is cut off, it becomes a strangulated hernia, which leads to tissue death. Symptoms of strangulation include fever, a rapid heart rate, and visible changes to the skin over the bulge, such as discoloration.
Gastrointestinal symptoms may also occur if a piece of intestine is trapped and obstructed, including nausea, vomiting, and an inability to pass gas or have a bowel movement. These acute, severe symptoms represent a life-threatening situation. Anyone experiencing this combination of signs should seek emergency medical care without delay.