Hernia: The Complete Medical Guide

What is a hernia?

A hernia is the protrusion of an organ or tissue — usually part of the intestine or the fatty apron of the abdomen (omentum) — through a weak spot or opening in the muscle or fascia that normally contains it.

A hernia typically appears as a bulge under the skin that gets bigger when standing, coughing or lifting, and shrinks or disappears when lying down.

The three parts of a hernia

1. Hernia defect (neck): the hole or weak point in the abdominal wall. A narrow neck with large contents increases the risk of strangulation.
2. Hernia sac: a pouch of peritoneum (the lining of the abdomen) pushed through the defect.
3. Contents: usually omentum (fat) or small bowel, sometimes colon, bladder or ovary.

Hernia in numbers

• Inguinal hernia is by far the most common type, accounting for about 75% of abdominal wall hernias.
• Lifetime risk of inguinal hernia is about 27% in men and 3% in women.
• More than 20 million groin hernia repairs are performed worldwide each year.
• Incisional hernia develops after 10–20% of abdominal operations, and in 30% or more of high-risk patients.
• 1–5% of children are born with an inguinal hernia, rising to about 30% in premature babies.
• Umbilical hernia is very common in infants and usually closes by itself by age 4–5.
• Femoral hernia is less common but has the highest risk of strangulation, and is more frequent in women.

Abdominal wall anatomy made simple

The abdominal wall is a multi-layered shield: skin and fat, the rectus abdominis ("six-pack") muscles joined in the midline by the linea alba, three lateral muscles (external oblique, internal oblique, transversus abdominis), and deep transversalis fascia and peritoneum.

Natural weak points include the inguinal canal, the umbilicus, the linea alba, the femoral canal and the oesophageal hiatus of the diaphragm. Most hernias occur exactly there. Any surgical scar is also a new weak point where an incisional hernia may develop.

Types of hernia

Rare hernias

• Spigelian hernia at the lateral edge of the rectus muscle — often needs CT to diagnose.
• Obturator hernia in the pelvis, typically in thin elderly women, often presenting as bowel obstruction.
• Lumbar hernia in the lower back.
• Parastomal hernia around a stoma.
• Richter's hernia, where only part of the bowel wall is trapped and can strangulate without obvious obstruction.
• Littre's (Meckel's diverticulum) and Amyand's (appendix) hernias.
• Sportsman's hernia — usually not a true hernia but an injury of the groin muscles and tendons in athletes.

Note: Diastasis recti (separation of the abdominal muscles) is not a hernia — there is no defect or sac, only widening of the linea alba. It frequently coexists with umbilical hernia after pregnancy.

Hernia symptoms

• A bulge that appears when standing, coughing or straining and disappears when lying down.
• Heaviness, dragging or burning at the site, worse at the end of the day.
• Pain when lifting or bending.
• In men, scrotal swelling with indirect inguinal hernia.
• With hiatal hernia: heartburn, reflux and difficulty swallowing, with no visible bulge.

Many hernias are asymptomatic and found by chance. Read more: Hernia symptoms and diagnosis.

Causes and risk factors

A hernia develops when two factors meet: a weak abdominal wall and increased intra-abdominal pressure.

Weakness: congenital defects (patent processus vaginalis, open umbilical ring), ageing, previous surgery and wound infection, genetics and collagen quality (family history roughly doubles the risk), and smoking.

Pressure: obesity, chronic cough, chronic constipation, prostate enlargement, pregnancy, heavy lifting and ascites.

Full details: Hernia causes, risk factors and prevention.

When is a hernia dangerous?

1. Reducible hernia: goes back in when lying down or with gentle pressure — the most common and least dangerous state.
2. Incarcerated (irreducible) hernia: contents stay trapped outside. Needs urgent surgical assessment.
3. Strangulated hernia: blood supply to the trapped bowel is cut off — a surgical emergency requiring an operation within hours.

Go to the emergency department immediately if you have: sudden severe pain at the hernia, a hard tender bulge that will not go back, red or dark discolouration of the skin, nausea and vomiting, abdominal distension, inability to pass gas or stool, or fever. Read: Hernia complications and strangulation.

Diagnosis

Most hernias are diagnosed by clinical examination — standing and lying, with a cough test. When needed:

• Dynamic ultrasound — first-line imaging for small or uncertain hernias.
• CT scan — best for large incisional, complex or rare hernias and surgical planning.
• MRI — for unexplained groin pain and sportsman's hernia.
• Upper endoscopy and barium swallow — for hiatal hernia.

Hernia treatment

Does a hernia go away on its own?

No. Adult hernias do not heal without surgery and tend to grow over time. The only exception is umbilical hernia in infants, which usually closes spontaneously. No medicine, herb or exercise closes a hernia defect.

Watchful waiting

According to the HerniaSurge international guidelines (2018), men with an asymptomatic or minimally symptomatic inguinal hernia may choose watchful waiting; however, up to ~70% eventually need surgery within 5–10 years as symptoms increase. Women are advised to have groin hernias repaired because of the higher chance of a femoral hernia. Read: Hernia treatment without surgery.

Hernia truss

A truss may temporarily relieve symptoms in patients unfit for surgery, but it does not cure the hernia or prevent strangulation, and may cause skin problems and scarring that complicate later surgery.

Surgery — the only cure

Surgery returns the contents, closes the defect and usually reinforces the wall with mesh to prevent recurrence.

Types of hernia surgery

1. Open surgery

• Lichtenstein repair: the gold standard open inguinal repair with a tension-free mesh. Simple, safe and possible under local anaesthesia.
• Shouldice repair: a multilayer suture repair without mesh — excellent results in expert hands.
• Open umbilical and epigastric repair with mesh, or sutures for very small defects.

2. Laparoscopic hernia surgery

• TAPP: the surgeon enters the abdomen and places mesh behind the wall.
• TEP: works entirely in the preperitoneal space without entering the abdomen.
• eTEP: an extended technique for large inguinal, midline and incisional hernias, placing a large retromuscular mesh away from the bowel.
• IPOM: a coated mesh placed inside the abdomen for ventral hernias.

Advantages: less pain, faster return to work, less chronic pain, repair of both sides through the same ports, and detection of hidden hernias.

3. Robotic surgery

An extension of laparoscopy with 3D vision and greater precision — useful in complex hernias, but more expensive.

4. Abdominal wall reconstruction for large and complex hernias

• Rives-Stoppa (sublay/retromuscular) repair — one of the best-performing techniques for midline hernias.
• Component separation and transversus abdominis release (TAR) for giant hernias.
• Pre-operative Botox and progressive pneumoperitoneum to prepare patients with loss of domain.

Details: Hernia surgery: types, preparation and results.

Hernia mesh

Hernia mesh, usually made of polypropylene, reinforces the wall; the body's tissue grows through it to form a stronger layer. Studies show mesh significantly reduces recurrence compared with suture alone in most adult hernias.

Much of the online fear about "mesh harm" relates to transvaginal gynaecological mesh, which is different from hernia mesh. Rare complications exist — infection, adhesions, pain — so mesh choice, position and surgical expertise make the difference.

Read: Hernia mesh: types, safety and complications.

Preparing for surgery

• Stop smoking at least 4–6 weeks before surgery.
• Lose weight before elective repair of large ventral hernias.
• Control blood sugar in diabetes.
• Treat chronic cough, constipation and prostate problems.
• Review medications, especially blood thinners, with your doctor.

Recovery

• Most inguinal and umbilical hernia patients go home the same or next day.
• Walking starts on the day of surgery.
• Desk work usually after 3–7 days; heavy work after 3–6 weeks depending on the operation.
• International guidelines recommend returning to normal activity as pain allows after uncomplicated groin hernia repair.
• Eat normally with plenty of fibre and water to avoid constipation.

Details: Recovery after hernia surgery day by day.

Complications

Of an untreated hernia: enlargement, incarceration, strangulation, bowel obstruction and skin damage over large hernias.

After surgery: seroma, bruising, wound infection, temporary urinary retention, chronic post-herniorrhaphy pain (troublesome in a small percentage), and recurrence — all much less frequent with a specialist surgeon. Read: Hernia complications.

Prevention

You cannot prevent congenital hernias, but you can reduce risk and recurrence by maintaining a healthy weight, quitting smoking, treating chronic cough, constipation and prostate problems, lifting correctly (bend the knees, keep the back straight, breathe out while lifting), and strengthening your core under guidance.

Hernia in special groups

• Children: inguinal hernias are repaired soon after diagnosis; umbilical hernias are usually observed until age 4–5. Read: Hernia in children.
• Pregnancy: umbilical hernia is common; repair is usually postponed until after delivery.
• Athletes: chronic groin pain may be a "sportsman's hernia" requiring MRI.
• Elderly: age alone is not a contraindication; planned surgery is far safer than emergency surgery.

Myths and facts

When to see a doctor

See a doctor for any new bulge, a hernia that becomes painful or larger, or one that does not go back when lying down — and immediately for signs of strangulation. Choosing a surgeon specialised in hernia and abdominal wall surgery is one of the most important factors for success.

Summary

Hernia is very common, but in adults it is cured only by surgery, and modern laparoscopic and mesh repairs are safe and effective with rapid recovery. Do not ignore a hernia, know the warning signs, and choose a specialist. Explore: inguinal, umbilical, incisional, epigastric, femoral, hiatal and paediatric hernia.