An incisional hernia develops when a section of your intestine or abdominal tissue pushes through a weakened area of your abdominal wall at the site of a previous surgical scar. This condition is one of the most common complications following abdominal surgery, and while most cases are not immediately life-threatening, they require careful attention and proper treatment to prevent serious complications.
How Common Are Incisional Hernias?
Incisional hernias represent a significant health concern for people who have undergone abdominal surgery. According to medical experts, up to 20% of people who have a laparotomy (open abdominal surgery) will develop this type of hernia at some point after their operation. The incidence varies depending on the type of surgery performed, with some studies suggesting the rate can range from 10% to as high as 33% following abdominal operations. [1][3][4]
These hernias can appear at any time following surgery. Some people notice a bulge within a few months of their operation, while others may not develop symptoms until several years later. Research indicates that most incisional hernias occur within the first year after abdominal surgery, though the timeline varies considerably from person to person. [4][9]
Incisional hernias are slightly more common following emergency surgical procedures compared to planned operations. They also occur more frequently after surgeries that require larger incisions, particularly those made vertically down the middle of the abdomen. However, they can develop even after minimally invasive procedures such as laparoscopic or robotic surgery, though the risk is generally lower with these techniques. [3]
What Causes an Incisional Hernia to Develop?
The fundamental cause of an incisional hernia is the failure of the abdominal wall to heal properly after surgery. When surgeons operate on your abdomen, they must cut through several layers of tissue, including skin, fat, and muscle. These layers need to grow back together tightly to maintain the strength and integrity of your abdominal wall. When this healing process doesn’t occur as it should, a gap or area of weakness can develop. [2][3]
Your abdominal cavity is under constant pressure from your internal organs, and this pressure naturally pushes against your abdominal wall. Normally, strong muscles and connective tissue hold everything in place. However, if the surgical incision site heals with a weakness, the pressure inside your abdomen can force tissue or organs to push through this weakened area, creating a bulge beneath your skin. This bulge is the hernia. [4]
The location of your surgical incision plays a role in hernia development. Midline incisions, which run vertically down the center of your abdomen, are associated with a higher rate of incisional hernias compared to incisions made in other locations. The type of material used to close the incision and the technique employed by the surgeon also influence the likelihood of hernia formation. [3]
Risk Factors That Increase Your Chances
While anyone who has had abdominal surgery can develop an incisional hernia, certain factors significantly increase the risk. Understanding these risk factors can help you take preventive measures and recognize when you might be at higher risk. [1][3]
Medical conditions that affect wound healing are among the most significant risk factors. If you have diabetes, your body’s ability to heal wounds is compromised, which can lead to weaker scar tissue at the incision site. People with kidney failure or other chronic diseases that impair tissue repair face similar challenges. Long-term use of certain medications, particularly corticosteroids and immunosuppressants, can also interfere with proper wound healing and increase hernia risk. [1][3]
Obesity is a major risk factor for incisional hernia development. When you carry excess weight, the pressure inside your abdomen is greater, which puts more strain on healing tissues. This increased pressure makes it harder for the surgical site to heal properly and easier for organs or tissue to push through any areas of weakness. Studies consistently show that people with a high body mass index are more likely to develop incisional hernias and experience complications after hernia repair surgery. [3][5]
Smoking significantly increases your risk of developing an incisional hernia. Tobacco use interferes with your body’s ability to form collagen, a protein that is essential for strong, healthy tissue. As collagen production decreases, the tissues in your abdominal wall become weaker and more vulnerable to hernia formation. Additionally, chronic coughing associated with smoking places repeated strain on the abdominal wall, further increasing the risk. Research shows that smokers are four times more likely to experience recurring hernias after surgical repair. [15]
Lung diseases that cause chronic coughing, such as chronic obstructive pulmonary disease (COPD), place repeated stress on the abdominal wall. Each time you cough forcefully, pressure builds inside your abdomen and pushes against the healing incision site. Over time, this repeated strain can prevent proper healing or cause an already healed incision to weaken. [1]
Surgical site infections are another important risk factor. When an infection develops at the incision site, it disrupts the normal healing process and can lead to the formation of weak scar tissue. Infections may also cause fluid accumulation or the formation of a hematoma (a collection of blood) at the wound site, both of which can interfere with proper healing. [2][3]
Emergency surgeries carry a higher risk of incisional hernia compared to planned procedures. This may be because emergency operations often occur under less-than-ideal conditions, and patients may have underlying health issues that compromise healing. The urgency of the situation may also limit the surgical team’s options for how they approach and close the incision. [3]
Recognizing the Symptoms
The symptoms of an incisional hernia can vary considerably depending on the size of the hernia and your individual circumstances. Some people with small hernias experience no symptoms at all and only discover the hernia during a routine physical examination. However, as hernias grow larger, they typically begin causing noticeable signs. [1][4]
The most common and recognizable symptom is a visible bulge or lump near your surgical scar. This bulge represents the tissue or organ that has pushed through the weakened area of your abdominal wall. The bulge may be soft to the touch and can vary in size. You might notice that it becomes more prominent when you stand up, cough, sneeze, or strain during a bowel movement. When you lie down flat, the bulge may disappear or become less noticeable as the pressure inside your abdomen decreases. [1][4]
Pain is another common symptom, though not everyone with an incisional hernia experiences discomfort. Small hernias, typically those measuring about 2 inches (5 centimeters) or less, often don’t cause pain. Larger hernias, particularly those measuring more than 4 inches (10 centimeters), are more likely to be painful. The pain can range from a sharp, sudden sensation to a dull, persistent ache. Many people find that their pain worsens when they engage in activities that increase abdominal pressure, such as lifting heavy objects, coughing, sneezing, or straining to have a bowel movement. [1]
Some people describe unusual sensations in the area of their hernia. These might include aching, burning, or gurgling feelings near the surgical site. You might also experience a sensation of pulling or pressure in the affected area, even when you’re not actively using your abdominal muscles. These sensations can be intermittent or constant, depending on your activities and the size of the hernia. [2][4]
Digestive symptoms can occur, particularly if part of your intestine is involved in the hernia. Some people experience nausea, constipation, or notice that their stools become thinner than usual. These symptoms develop because the herniated section of intestine may not function as efficiently as it should. [2]
Preventing Incisional Hernias
While you cannot completely eliminate your risk of developing an incisional hernia, there are several steps you can take to significantly reduce your chances. The most important preventive measure is giving your body adequate time to heal after surgery. Your abdominal muscles need several weeks or even months to regain their strength, and protecting them during this critical period is essential. [1][9]
Avoiding strenuous activities in the months following your surgery is crucial. Your surgeon will provide specific guidance about when you can safely resume different types of activities. Generally, you should avoid heavy lifting, intense exercise, and activities that require you to strain your abdominal muscles for at least four to six weeks after surgery. When you do need to lift something, use proper technique by bending your knees and lifting with your legs rather than your back and abdomen. [2][9]
Maintaining a healthy weight is one of the most effective ways to prevent incisional hernias. If you are overweight or obese, losing weight can significantly reduce the pressure inside your abdomen and decrease the strain on your healing incision. Even modest weight loss can make a meaningful difference. If you were planning to lose weight before your surgery, discuss with your doctor whether it might be beneficial to wait until after you’ve achieved a healthier weight, if the surgery is not urgent. [5][9]
Preventing constipation and avoiding straining during bowel movements is important for protecting your healing abdominal wall. Straining increases pressure inside your abdomen, which can stress the surgical site. You can prevent constipation by drinking plenty of water, eating a diet rich in fiber, and staying as active as your doctor recommends. If you do experience constipation, stool softeners may be helpful and are often recommended following abdominal surgery. [2]
If you smoke, quitting is one of the best things you can do to prevent an incisional hernia. In addition to improving your overall health, stopping smoking enhances your body’s ability to heal properly. The benefits of quitting begin almost immediately, so even if your surgery is already scheduled, quitting now can still help. Your doctor can provide resources and support to help you quit smoking. [9][15]
If you have diabetes or other chronic conditions that affect wound healing, work closely with your healthcare team to manage these conditions effectively. Keeping your blood sugar levels well-controlled if you have diabetes can significantly improve your body’s ability to heal after surgery. Similarly, managing other chronic conditions optimally before and after surgery can reduce your risk of complications. [2]
Treating any persistent cough before surgery, when possible, can help reduce your risk. If you have a chronic cough due to allergies, asthma, or another treatable condition, addressing it before undergoing elective abdominal surgery may help prevent hernia formation. If you develop a cough after surgery, seek treatment promptly to minimize the strain on your healing abdomen. [9]
Understanding What Happens in Your Body
To understand an incisional hernia, it helps to know how your abdominal wall is structured and what changes occur when a hernia develops. Your abdominal wall is composed of several layers that work together to contain and protect your internal organs. The outermost layer is your skin, beneath which lies a layer of fat. Below the fat are the abdominal muscles, which provide the primary strength and support for your abdomen. The innermost layer is a thin membrane called the peritoneum, which lines the inside of your abdominal cavity. [3]
When surgeons perform abdominal surgery, they must cut through all these layers to access the organs inside. After the surgical procedure is complete, the layers are carefully closed with stitches or other closure methods. In a normal healing process, the cut edges of tissue grow back together, and new collagen forms to create strong scar tissue. This process typically takes several weeks, during which time the incision gradually regains strength. [3]
However, in some cases, the healing process doesn’t proceed as it should. The edges of the cut tissue may not grow together tightly enough, or the scar tissue that forms may be weaker than the original tissue. This creates a gap or area of weakness in the abdominal wall. Your abdominal cavity is under constant pressure from your organs and from activities like breathing, coughing, and moving. When there’s a weak spot in the abdominal wall, this pressure can push the peritoneum (the inner lining) through the gap, creating a sac. Parts of your intestine or other abdominal contents can then slide into this sac, forming the visible bulge that characterizes a hernia. [4]
The size of the gap in your abdominal wall determines the size of your hernia. Small gaps result in small hernias that might be barely noticeable, while larger gaps can allow more tissue to push through, creating larger and more obvious bulges. Over time, hernias tend to grow larger as the pressure inside your abdomen continues to push against the weakened area. This is why hernias typically don’t get better on their own and often require surgical intervention. [6]
In some hernias, the contents of the sac can slide back and forth through the gap. These are called reducible hernias, and the bulge may disappear when you lie down or when you gently push on it. In other cases, the contents become stuck in the sac and cannot be pushed back into the abdomen. This is called an incarcerated hernia, which is more concerning because it can lead to complications. [2][17]
The development of an incisional hernia is not simply a mechanical problem. Multiple biological factors influence whether and when a hernia forms. The quality and quantity of collagen your body produces affects the strength of your healing tissues. Your immune system’s response to the surgery influences how well the wound heals. Inflammation at the surgical site, whether from normal healing or from infection, plays a role in determining the final strength of the repaired tissue. All these factors interact to determine whether your abdominal wall heals with normal strength or develops areas of weakness that allow hernias to form. [3]
