The most serious complications after hernia mesh surgery can be deadly.

At the very least, they can cause severe pain. They almost always need revision surgery to correct.

The most serious complications of hernia mesh are also some of the most common.

Hernia mesh complications include adhesion, bowel obstruction or perforation, infection, rejection and migration.

More than 90 percent of the 1-million-plus hernia surgeries performed every year in the U.S. rely on hernia mesh for repairs.

Nearly one-third of people who undergo hernia surgeries experience some sort of complication, with excessive pain being the most frequent complaint, according to one study.

The U.S. Food and Drug Administration describes adhesions as “scar-like tissue that sticks tissues together.”

Chronic, often severe, pain may be a patient’s only symptom of a mesh adhesion. The condition can also lead to life-threatening bowel obstructions.

Intraperitoneal surgery is a technique that leaves mesh in contact with the intestines. The intestines and the repair stick together around the mesh.

Manufacturers have developed different materials or coatings to prevent adhesion. But the problem still occurs in some surgeries.

A 2009 study in the British Journal of Surgery found that the body absorbs the coating over time. The mesh then comes in contact with the intestines.

Researchers found that the coating reduced adhesions for up to a week. But after a month, there was no advantage in preventing them.

Hernia mesh can cause a bowel obstruction if it adheres to the intestines. Mesh sometimes creates obstructions when it migrates in the body. If it moves, mesh can entrap loops of the intestines.

Bowel obstructions are a dangerous condition. They need immediate treatment.

Left untreated, an obstruction can cut off blood flow, causing part of the intestine to die.

Surgeons may have to remove part of the intestine if mesh causes a bowel obstruction.

The FDA cites recalled mesh as a major cause of bowel perforation and obstruction.

Bowel perforation happens when hernia mesh punctures or erodes into the bowel.

Mesh may also perforate the abdominal wall or another organ in the abdomen.

A bowel perforation allows fecal matter and bacteria into the abdominal cavity. This can cause peritonitis.

Peritonitis is a dangerous form of inflammation.

Perforation can also cause sepsis, a sometimes fatal bloodstream infection.

People should consider any bowel perforation a life-threatening medical emergency.

Antibiotics can treat minor infections around the suture site on the skin.

Deep, chronic infections around hernia mesh are harder to treat.

Patients often need surgery to remove the mesh.

This is usually accompanied with intravenous antimicrobial treatments.

Chronic infection symptoms may not occur until years after hernia mesh surgery.

Materials in hernia surgical mesh may sometimes trigger the body’s immune response.

This can cause the body to reject the mesh.

Patients should seek medical attention if they experience mesh rejection symptoms.

If hernia mesh detaches after surgery, there is a risk it can migrate through the abdomen.

It can lead to adhesions, fistulas, abscesses and bowel obstruction or perforation.

Detachment is more likely to happen in laparoscopic (minimally invasive) hernia surgery techniques.

Migration may result in excess pain, or it may be symptom-free until it causes more severe damage.

One of the most common complications of hernia surgery is that hernias can come back.

Doctors call this “recurrence.”

Surgeons began using hernia mesh to overcome this problem. The idea is that mesh can further reinforce weakened tissue.

But using mesh is no guarantee against recurrence.

Mesh detachment or migration can let a hernia return. A patient’s health and lifestyle can also affect the chances of recurrence.

Hernia mesh complications can happen shortly after surgery or years later.

A 2016 study found that the number of complications increased over the course of five years.

Out of 3,242 study participants, 1,050 required another abdominal surgery.

Some hernia mesh complications share symptoms. But some symptoms are unique to a particular complication.

Hernia mesh complications can be hard to diagnose. People who experience these symptoms should tell their doctors that they have hernia mesh.

There are several diagnostic tests doctors can use to detect hernia mesh complications.

These include X-rays, CT scans and blood tests.

Depending on the complication, a surgeon may decide to perform surgery to remove the mesh.

Doctors may rely on surgery, medication or a combination of both to treat an adhesion or fistula.

Surgery may be the only option for patients with bowel or abdominal perforation.

Surgeons will have to remove the mesh and repair the hole.

They may also remove the damaged section of the bowel.