What Is a Hernia? Types, Symptoms and When Repair Is Needed

A hernia is a protrusion of tissue or an organ through a weak spot or opening in the wall that normally contains it. The abdominal wall is the most common site: a layered structure of muscle and tough connective tissue (fascia) that holds the abdominal contents in place. Where that wall is naturally thinner, has been weakened by surgery, or is placed under repeated strain, abdominal fat or a loop of bowel can push through and form a bulge.

The main types of abdominal wall hernia

• Inguinal hernia — in the groin, through the inguinal canal. By far the most common type, and much more common in men than in women. It can be indirect (through the deep inguinal ring) or direct (through a weak area of the posterior wall of the canal).
• Femoral hernia — just below the groin crease, through the femoral canal. Less common, more frequent in women, and with a higher risk of becoming trapped, so it is usually repaired promptly.
• Umbilical and para-umbilical hernia — at or beside the navel. Common in infants, where many close on their own, and in adults, where they tend to enlarge.
• Epigastric hernia — in the midline between the navel and the breastbone, usually containing fat.
• Incisional hernia — through the scar of a previous abdominal operation. A significant proportion of midline laparotomies develop one over time.
• Ventral hernia — a general term for hernias of the front abdominal wall, including umbilical, epigastric and incisional hernias.

A hiatal hernia, in which part of the stomach moves up through the diaphragm, is a different condition with different treatment and is not covered here.

Why hernias develop

Most hernias result from a combination of a weak point and increased pressure inside the abdomen. Contributing factors include heavy lifting and straining, chronic cough, constipation, pregnancy, obesity, smoking (which impairs collagen and wound healing), connective-tissue factors, ageing and — for incisional hernias — wound infection or poor healing after previous surgery.

Symptoms

The typical sign is a bulge that is more obvious when standing, coughing or straining and that may disappear when lying down. Many people describe a dragging, aching or heavy feeling, especially at the end of the day. Some hernias cause no symptoms and are found on examination.

Warning signs that need urgent care

A hernia becomes an emergency when its contents are trapped (incarcerated) or their blood supply is cut off (strangulated). Seek urgent medical attention for:

• a hernia bulge that becomes firm, tender and cannot be pushed back;
• sudden, severe or increasing pain at the hernia;
• nausea, vomiting, a swollen abdomen or inability to pass wind or stool;
• redness or discolouration of the skin over the hernia, or fever.

How hernias are repaired

Hernias do not heal by themselves in adults; surgery is the only definitive treatment. For some adults with small, minimally symptomatic inguinal hernias, a surgeon may advise watchful waiting, but many of these patients eventually choose repair as symptoms increase.

Repair can be performed:

• Open — through an incision over the hernia, for example the Lichtenstein tension-free repair for inguinal hernia.
• Laparoscopically — through small ports, for example TAPP or TEP for inguinal hernia, or intraperitoneal onlay mesh (IPOM) repair for ventral hernias.
• Robotically — a minimally invasive variant now used in many centres.

In most adult hernia repairs today the defect is reinforced with a surgical mesh, which spreads the load across a wider area and allows tissue to integrate with the implant. We look at how mesh repair compares with suture repair in Mesh vs Non-Mesh Hernia Repair.

Which mesh for which hernia?

The choice depends on the hernia, the approach and the plane in which the mesh is placed:

• Open and laparoscopic groin repairs commonly use a flat knitted polypropylene mesh such as Knit, or a pre-shaped anatomical mesh such as Knit 3D.
• Repairs in which the mesh will face the bowel need a composite mesh with a visceral-side barrier — Silene, Teflene, Ultralene or Duolene.
• Where a lighter permanent footprint is preferred, a partially absorbable mesh such as Monosolve V2 is an option.

The final choice always rests with the operating surgeon.

This article is general information for healthcare professionals and patients and is not medical advice. Anyone with a suspected hernia should be assessed by a doctor.