An incisional hernia is a bulge that pushes through the site of a previous surgical incision on your abdomen. It develops when the layers of your abdominal wall fail to heal properly after surgery, leaving a weak spot that allows tissue or part of the intestine to protrude. Roughly 9 to 11% of people who undergo abdominal surgery will develop one, sometimes years after the original operation.
How an Incisional Hernia Forms
Your abdominal wall is made of several layers of muscle and tough connective tissue called fascia. When a surgeon cuts through these layers, they stitch them back together afterward, and healing depends on the cut edges fusing tightly. If gaps remain between those edges, scar tissue fills in instead of strong fascia. Scar tissue is weaker and more prone to stretching under pressure.
For a hernia to fully develop, more than one layer of the abdominal wall has to fail. That’s why it doesn’t always happen right away. Ongoing pressure from inside the abdomen, whether from coughing, straining, or carrying extra weight, gradually pushes against the weakened spot until the tissue bulges outward. The hernia itself is essentially a sac of abdominal lining (and sometimes intestine or fatty tissue) poking through that gap.
What It Looks and Feels Like
The hallmark sign is a visible bulge near or along your surgical scar. It’s most noticeable when you’re standing upright or straining, such as during heavy lifting, coughing, or bearing down. Lying flat often makes it shrink or disappear entirely because gravity is no longer pushing contents through the opening.
Many incisional hernias cause only mild discomfort or a dragging sensation around the scar. Others are painless and discovered incidentally. Larger hernias can cause aching that worsens over the course of the day or after physical activity. In some cases, you can gently push the bulge back in, which is a sign that the hernia contents are still moving freely.
Risk Factors That Make It More Likely
Several factors increase the chance your surgical wound won’t heal strongly enough to resist a hernia. The biggest modifiable ones are obesity, smoking, and diabetes. A BMI over 30 raises the risk of wound complications that compromise healing, and guidelines from both the European Hernia Society and the Americas Hernia Society recommend getting BMI below 35 before elective repair and quitting smoking for at least four to six weeks beforehand.
Other factors include:
- Wound infection after the original surgery. Infection is one of the strongest predictors of later hernia development because it disrupts the healing process at its most critical stage.
- Midline incisions. Cuts running vertically down the center of the abdomen are under more tension and have higher hernia rates than other incision locations.
- Repeat surgeries through the same incision. Each reoperation weakens the tissue further.
- Chronic conditions that raise abdominal pressure. COPD, prolonged coughing, chronic kidney disease, and urinary obstruction all create sustained internal force against the healing wound.
When a Hernia Becomes an Emergency
Most incisional hernias are not dangerous, but two complications require urgent care. The first is incarceration, where the tissue that has pushed through the opening gets trapped and can no longer be pushed back in. The bulge becomes firm, tender, and doesn’t change with position.
If incarceration persists, blood flow to the trapped tissue gets cut off. This is strangulation, and it can cause the trapped bowel or tissue to die. Symptoms escalate to severe pain at the hernia site along with nausea, vomiting, bloating, and signs of bowel obstruction. In older adults, the local pain may be subtle, and the only clues might be vomiting and abdominal distension, which can be mistaken for a simple bowel blockage. Strangulated hernias need emergency surgery.
How It’s Diagnosed
A doctor can often diagnose an incisional hernia through a physical exam alone, especially if the bulge is obvious when you stand or bear down. When the hernia is small or the diagnosis is uncertain (particularly in patients with higher body weight where the bulge is harder to see or feel), imaging with a CT scan or ultrasound can confirm the defect and measure its size. Imaging also helps surgeons plan a repair by showing exactly how wide the opening is and what’s inside the hernia sac.
Surgical Repair Options
Incisional hernias don’t heal on their own. They tend to enlarge over time, and the standard treatment is surgical repair. The two main approaches are open surgery and laparoscopic (keyhole) surgery, and both typically involve placing a synthetic mesh over the weakened area to reinforce it.
Mesh reinforcement matters. When surgeons compared mesh repair to simple stitching of the defect, mesh brought the recurrence rate down to about 2.7% compared to 8.2% with stitches alone. The tradeoff is a slightly higher rate of fluid collection and wound infection at the mesh site, but the significant reduction in recurrence is why mesh has become the standard approach.
Laparoscopic vs. Open Repair
Laparoscopic repair uses small incisions and a camera to place the mesh from inside the abdomen. Compared to traditional open repair, the differences in recovery are significant. In one study, the average hospital stay after laparoscopic repair was about 2 days versus 8 days for open surgery. Operating time averaged roughly one hour for laparoscopic cases and nearly three hours for open procedures. Complications occurred in 16% of laparoscopic patients compared to 50% of those who had open repair. Both methods had very low recurrence rates.
Not every hernia is suitable for laparoscopic repair. Very large defects or hernias with significant scar tissue from prior surgeries may require an open approach. Some complex cases involve reconstructing the abdominal wall itself, which is a longer and more involved procedure.
Recovery After Repair
The most common recommendation is about four weeks of reduced lifting and physical labor after a standard mesh repair. A survey of hernia specialists found that more than half considered four weeks appropriate for the most common repair techniques. For complex repairs involving larger defects or abdominal wall reconstruction, many surgeons felt four weeks was too short and recommended five to sixteen weeks of restrictions instead.
In practice, pain is the most useful guide. Research has shown that even lifting 50 kilograms (about 110 pounds) causes only a negligible rise in abdominal pressure, so the concern is less about mechanical failure of the repair and more about letting the tissues heal comfortably. Most surgeons advise resuming full physical activity when you can do so without pain. After laparoscopic repair, many people return to normal daily activities within one to two weeks, with full exertion cleared around the four-week mark.
Prevention During the Initial Surgery
Because incisional hernias are so common after abdominal surgery, there’s growing interest in preventing them at the time of the original operation. Both the European and American Hernia Societies now recommend placing a preventive mesh during abdominal wall closure in high-risk patients. High-risk categories include people with diabetes, obesity, COPD, smoking history, immunosuppression, or those who developed a wound infection. Vascular surgery guidelines specifically recommend preventive mesh reinforcement when closing the abdomen after open aortic aneurysm repair, a procedure with particularly high hernia rates.
For patients who haven’t yet had surgery but know they’re at higher risk, losing weight and stopping smoking beforehand are the two most impactful steps. These changes improve wound healing and reduce the chronic abdominal pressure that contributes to hernia formation in the months after surgery.