Surgery :Hernias and the abdominal wall

🩹 Hernias and the abdominal wall . Hernias are among the commonest reasons for surgery. Most are harmless bulges, but a hernia that becomes painful, tender and irreducible can strangulate -cutting off the blood supply to bowel -and needs emergency surgery. Femoral hernias in older women are the classic dangerous ones. Always examine the hernial orifices in anyone with bowel obstruction.
Your four questions for every patient: Is this a hernia, and which type? Is it reducible, or is it incarcerated, obstructed or strangulated? Does it need surgery -routinely, urgently or as an emergency? Is the patient fit, and what are their wishes and risk factors (smoking, obesity, cough, constipation)?

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What Is a Hernia?

• A hernia -part of an organ or tissue (usually bowel or fat) pushes through a weakness in the wall of the cavity that normally contains it.
• Terms:
  • Reducible -goes back in (by itself when lying down, or with gentle pressure).
  • Irreducible (incarcerated) -can't be pushed back, but the blood supply is intact.
  • Obstructed -bowel trapped in the hernia is blocked → bowel obstruction.
  • Strangulated -the blood supply to the trapped tissue is cut off → ischaemia and gangrene within hours -emergency.
  • Richter's hernia -only part of the bowel wall is trapped -it can strangulate without causing obstruction (easily missed).
  • Sliding hernia -part of the hernia sac wall is formed by an organ (e.g. bladder or caecum).
• Risk factors -conditions that raise abdominal pressure (chronic cough, constipation, straining to pass urine -prostate enlargement, heavy lifting, obesity, pregnancy, ascites, peritoneal dialysis) and those that weaken the wall (age, previous surgery, wound infection, smoking, steroids, connective tissue disorders, male sex for inguinal hernias).
• Symptoms -a lump that appears on standing, coughing or straining and goes away when lying down; aching or dragging discomfort; sometimes none.

Anatomy of the Groin

• Inguinal canal -an oblique passage about 4 cm long above the medial half of the inguinal ligament, carrying the spermatic cord in men (the round ligament in women) and the ilioinguinal nerve.
• Deep (internal) ring -a hole in the transversalis fascia, about 1–1.5 cm above the midpoint of the inguinal ligament, just lateral to the inferior epigastric vessels.
• Superficial (external) ring -a gap in the external oblique aponeurosis, above and medial to the pubic tubercle.
• Walls ("MALT") -roof: Muscles (internal oblique and transversus); anterior: Aponeurosis of external oblique; floor: inguinal Ligament; posterior: Transversalis fascia (and conjoint tendon medially).
• Hesselbach's triangle -bounded by the inferior epigastric vessels (lateral), the edge of rectus abdominis (medial) and the inguinal ligament (below) -the site of direct inguinal hernias.
• Femoral canal -below the inguinal ligament, medial to the femoral vein (from lateral to medial: Nerve, Artery, Vein, Empty space, Lymphatics -"NAVEL"); its narrow, rigid neck explains why femoral hernias strangulate.
• Landmarks -the pubic tubercle is the key: inguinal hernias appear above and medial to it; femoral hernias below and lateral to it.

Examining a Groin Lump

• Examine standing and lying, both sides, with the patient's consent and a chaperone; expose from the umbilicus to the upper thighs, including the scrotum.
• Inspect -site, size, shape, skin changes, scars; ask the patient to cough and watch for a bulge.
• Palpate -tenderness, temperature, consistency, cough impulse, reducibility (ask the patient to reduce it, or reduce gently lying down), relationship to the pubic tubercle.
• Scrotal lumps -can you get above it? If not, it is coming from the groin (an inguinoscrotal hernia); if you can, it arises in the scrotum (hydrocele, cyst, testicular mass -see the Urology page).
• Deep ring occlusion test -pressing over the deep ring after reduction; if the hernia doesn't reappear on coughing, it suggests an indirect hernia -but this is unreliable at distinguishing direct from indirect (the surgeon confirms at operation).
• Also check -the other side, abdomen (masses, ascites, scars), causes of raised pressure (cough, constipation, prostate symptoms), and the testes.
• Imaging -usually not needed; ultrasound if the diagnosis is unclear (small or occult hernias, groin pain); CT in obstruction or for complex abdominal wall hernias.

Inguinal Hernias

• The commonest hernia -much more common in men (lifetime risk about 1 in 4 men); can occur at any age.
• Indirect inguinal hernia:
  • Passes through the deep ring, lateral to the inferior epigastric vessels, along the canal, and can descend into the scrotum.
  • Caused by a persistent processus vaginalis (a congenital sac) -the type seen in children and young men.
  • More likely to become incarcerated than direct hernias.
• Direct inguinal hernia:
  • Bulges through the weak posterior wall (Hesselbach's triangle), medial to the inferior epigastric vessels.
  • An acquired weakness in older men; a wide neck -rarely strangulates; seldom enters the scrotum.
• Management:
  • Symptomatic hernias -offer repair (usually day case).
  • Minimal or no symptoms in men -watchful waiting is reasonable (low risk of complications), but many eventually develop symptoms and choose repair.
  • Women -repair because of the risk of a femoral hernia being mistaken for an inguinal one (laparoscopic repair covers both).
  • Children -repair soon after diagnosis (herniotomy), urgently in infants (high risk of incarceration).
• Reduce risk factors -stop smoking, treat chronic cough and constipation, investigate prostate symptoms, weight loss.

Femoral Hernias

• Through the femoral canal, below the inguinal ligament, below and lateral to the pubic tubercle, medial to the femoral vein.
• Who -more common in women (wider pelvis), especially older, thin women; but inguinal hernias are still more common in women overall.
• Features -a small, firm lump in the upper medial thigh; often irreducible and with no cough impulse; frequently presents with bowel obstruction (sometimes the lump is overlooked, especially in obese patients) or as a Richter's hernia.
• High risk of strangulation -the neck is narrow and rigid -so all femoral hernias should be repaired promptly (urgently if symptomatic), and an obstructed or strangulated femoral hernia needs emergency surgery.
• Differential -inguinal hernia, saphena varix (soft, bluish, disappears on lying down, cough thrill, varicose veins), enlarged lymph node, femoral artery aneurysm (pulsatile), psoas abscess, lipoma.

⚠️ Safety Pearl: In an older woman with small bowel obstruction and no previous surgery, look carefully for a small femoral hernia -it is easily missed, especially in obesity, and strangulates readily.

Umbilical, Paraumbilical and Epigastric Hernias

• Umbilical hernia in infants -through the umbilical ring; common (especially in premature babies and children of Black African or Caribbean family origin); soft, reducible, rarely complicated; most close by about 4–5 years -repair if persisting beyond that or very large.
• Paraumbilical hernia in adults -through the linea alba just above or below the umbilicus; risk factors -obesity, multiple pregnancies, ascites, previous laparoscopic port; narrow neck -risk of incarceration and strangulation; repair (often with mesh) if symptomatic.
• Umbilical hernias in cirrhosis with ascites -can ulcerate and rupture (leaking ascitic fluid -emergency); treat the ascites; repair is higher risk (specialist decision).
• Epigastric hernia -small defects in the linea alba between the umbilicus and xiphisternum, usually containing fat; can be painful; repair if symptomatic.
• Divarication of the recti -a midline bulge on sitting up, without a defect -not a hernia (see below).

Incisional and Parastomal Hernias

• Incisional hernia -through a previous surgical scar; occurs after a significant proportion of midline laparotomies, often in the first 1–2 years.
  • Risk factors -wound infection, obesity, smoking, steroids, diabetes, malnutrition, chronic cough, emergency surgery, poor closure technique; also after port sites.
  • Prevention -"small bites" closure technique, prophylactic mesh in some high-risk patients, treating wound infections promptly.
  • Features -bulge near the scar on standing or coughing; often a wide neck (lower risk of strangulation), but smaller or multiple defects can trap bowel.
  • Management -conservative (binder) or mesh repair (open or laparoscopic); very large hernias with "loss of domain" need specialist abdominal wall reconstruction; optimise weight and stop smoking first.
• Parastomal hernia -a hernia beside a stoma; very common (especially colostomies); causes bulging, difficulty with the stoma appliance, pain and obstruction; managed with support garments, or surgical repair (often with mesh) if symptomatic; prophylactic mesh is used at stoma formation in some centres.

Rarer Hernias

Hernia	Site	Key features
Spigelian	Along the semilunar line (lateral edge of rectus), usually below the umbilicus	Lies under the external oblique -hard to feel; pain and a vague lump; ultrasound or CT; risk of incarceration -repair
Obturator	Through the obturator canal in the pelvis	Thin, older women; presents with small bowel obstruction; Howship–Romberg sign (pain down the inner thigh to the knee from obturator nerve compression); CT diagnosis
Lumbar	Inferior (Petit's) or superior (Grynfeltt's) lumbar triangles	Flank bulge; after trauma or flank surgery
Perineal and sciatic	Pelvic floor, sciatic foramen	After abdominoperineal resection; very rare
Internal hernias	Inside the abdomen -through mesenteric defects	After gastric bypass (e.g. Petersen's space) -intermittent colicky pain, SBO; CT may be normal; low threshold for laparoscopy
Maydl's hernia	Two bowel loops in the sac ("W" hernia)	The loop inside the abdomen can strangulate unseen -inspect at surgery

Hiatus and Diaphragmatic Hernias

• Sliding hiatus hernia (most) -the gastro-oesophageal junction slides up into the chest; associated with reflux; managed with PPIs and lifestyle measures; surgery (fundoplication) for selected patients (see the Upper GI page).
• Rolling (paraoesophageal) hiatus hernia -part of the stomach rolls up beside the oesophagus while the junction stays in place; can twist (gastric volvulus) or strangulate -chest pain, vomiting, inability to vomit or pass an NG tube; symptomatic ones are usually repaired.
• Congenital diaphragmatic hernia -in newborns (usually left-sided -Bochdalek); bowel in the chest, lung hypoplasia, breathing difficulty at birth (see the Neonatology chapter); Morgagni hernias -anterior, often found incidentally in adults.
• Traumatic diaphragmatic rupture -after blunt or penetrating trauma (usually left side); may present years later with bowel obstruction or breathlessness.

Incarceration, Obstruction and Strangulation

• Features of a complicated hernia:
  • Incarcerated -a lump that won't go back, often with discomfort but no systemic upset.
  • Obstructed -plus colicky abdominal pain, vomiting, distension and constipation.
  • Strangulated -a tense, tender, red or dusky lump, constant pain, fever, tachycardia, raised white count and lactate, peritonism; the skin may be discoloured.
• Management:
  • Resuscitation, analgesia, nil by mouth, IV fluids, NG tube if obstructed, bloods (lactate), urgent surgical review.
  • Gentle reduction ("taxis") may be attempted for a recently incarcerated, non-tender hernia with no signs of strangulation, with analgesia -then plan early repair.
  • Don't forcibly reduce a tender, possibly strangulated hernia -you may push dead bowel back into the abdomen, or reduce the sac with the bowel still trapped ("reduction en masse").
  • Emergency surgery for obstruction or strangulation -inspect the bowel, resect if non-viable, repair the defect (mesh may be avoided in contaminated fields).
• Which hernias are most likely to strangulate -those with a narrow neck: femoral, paraumbilical, indirect inguinal, obturator, Spigelian; direct inguinal and large incisional hernias with wide necks are lower risk.

Hernia Repair

• Inguinal hernia repair:
  • Open mesh repair (Lichtenstein) -under general, regional or local anaesthetic; day case; good for unilateral primary hernias and frail patients.
  • Laparoscopic repair (TEP -totally extraperitoneal, or TAPP -transabdominal preperitoneal) -mesh placed behind the muscles; preferred for bilateral and recurrent (after open) hernias and in women; needs general anaesthesia; quicker return to activity and less chronic pain in some.
  • Children -herniotomy (tying off the sac) without mesh.
• Femoral hernia repair -open (low or high approach) or laparoscopic, usually with mesh; emergency repair with possible bowel resection if strangulated.
• Umbilical, paraumbilical and epigastric -sutured repair for small defects; mesh for larger ones (lower recurrence).
• Incisional -mesh repair (open or laparoscopic); complex reconstruction (component separation) for large defects.
• Before surgery -optimise smoking, weight, diabetes and cough; check anticoagulants; consent including risks of recurrence and chronic pain.
• Mesh -reduces recurrence; complications include infection, chronic pain, and rarely adhesions or erosion; mesh for hernia repair remains standard (unlike vaginal mesh, which has restrictions in the UK).

Complications of Repair and Recovery

• Early -pain, bruising and haematoma (scrotal swelling), seroma, wound infection, urinary retention (especially after laparoscopic or spinal anaesthesia in older men).
• Later:
  • Chronic groin pain -in a minority (around 1 in 10 have some, a few have severe pain); nerve irritation (ilioinguinal, iliohypogastric, genitofemoral) -analgesia, nerve blocks, sometimes surgery.
  • Recurrence -a few per cent after mesh repair; higher after emergency repair, infection, obesity and smoking.
  • Testicular problems -ischaemic orchitis and atrophy (damage to testicular blood vessels), injury to the vas deferens (fertility).
  • Mesh infection (may need removal), bowel or bladder injury (rare, mainly laparoscopic).
• Recovery advice -walk from the day of surgery; light activities within days; usually avoid heavy lifting for about 4–6 weeks (follow the surgeon's advice); return to desk work in 1–2 weeks, manual work longer; driving when able to do an emergency stop without pain; check with insurers.

Divarication, Haematoma and Abdominal Wall Lumps

• Divarication of the recti (diastasis recti) -widening of the linea alba between the rectus muscles, causing a midline ridge on sitting up; common after pregnancy and in obesity; no risk of strangulation; physiotherapy (core exercises); surgery rarely needed.
• Rectus sheath haematoma -bleeding into the rectus sheath (anticoagulants, coughing, trauma, injections): sudden abdominal wall pain and a tender mass that doesn't cross the midline and becomes more obvious on tensing the abdominal muscles (Fothergill's sign); CT confirms; usually conservative (review anticoagulation, transfuse if needed); embolisation if bleeding continues.
• Other abdominal wall lumps:
  • Lipoma -soft, mobile, painless.
  • Epidermoid (sebaceous) cyst -skin-attached with a central punctum.
  • Scar endometriosis -a painful lump in a caesarean scar that swells with periods.
  • Desmoid tumour -firm, slowly growing mass in the muscle (after pregnancy, in familial adenomatous polyposis).
  • Sister Mary Joseph nodule -a hard lump at the umbilicus from metastatic abdominal or pelvic cancer (stomach, ovary, colon, pancreas).
  • Abscesses, skin cancers, injection site lumps (insulin lipohypertrophy).

Hernias in Children

• Inguinal hernias -more common in boys and in premature babies; always indirect (patent processus vaginalis); a groin or scrotal swelling that comes and goes with crying; high risk of incarceration in infants -refer promptly for herniotomy (urgently if under about 6 months or incarcerated; incarcerated hernias in infants can damage the testis or bowel).
• Hydroceles in infants -a fluid-filled sac (communicating with the abdomen in many) -transilluminates; most resolve by 1–2 years; surgery if persisting.
• Umbilical hernias -very common; most resolve by 4–5 years.
• Irreducible groin swelling in a child -consider incarcerated hernia, testicular torsion, torsion of an undescended testis, or an encysted hydrocele of the cord -urgent surgical assessment.
• See the Paediatric Gastroenterology and Surgery chapter.

Groin and Abdominal Wall Lumps at a Glance

Lump	Key features	Action
Indirect inguinal hernia	Above and medial to the pubic tubercle, cough impulse, may enter the scrotum; children and young men	Repair if symptomatic; children -herniotomy
Direct inguinal hernia	Medial, broad bulge in Hesselbach's triangle; older men; rarely strangulates	Repair or watchful waiting
Femoral hernia	Below and lateral to the pubic tubercle; older women; often irreducible	Repair all -urgently
Saphena varix	Soft, bluish, disappears lying down, cough thrill, varicose veins	Vascular assessment
Lymph node	Firm, may be multiple; look for infection or cancer in the drainage area	Examine legs, perineum, anus; investigate
Femoral artery aneurysm	Pulsatile and expansile	Vascular referral
Hydrocele / epididymal cyst	Scrotal; can get above it; transilluminates	Ultrasound, urology
Undescended testis	Empty scrotum on that side	Paediatric surgery (orchidopexy)
Psoas abscess	Groin swelling with fever, hip flexion, back pain (TB, Crohn's, discitis)	CT, drainage
Paraumbilical hernia	Next to the umbilicus; obesity, ascites	Repair if symptomatic
Incisional hernia	Through a scar	Optimise, then mesh repair if symptomatic
Divarication of recti	Midline ridge on sitting up; no defect	Reassure; physiotherapy
Sister Mary Joseph nodule	Hard umbilical nodule	Look for intra-abdominal cancer

Spot the Diagnosis

Clue	Diagnosis
Groin bulge in a 6-week-old boy that appears when crying	Indirect inguinal hernia -prompt repair
Bulge passing into the scrotum in a 30-year-old man; can't get above it	Indirect inguinoscrotal hernia
Broad bulge medial to the inferior epigastric vessels in a 70-year-old man	Direct inguinal hernia
Small firm irreducible lump below and lateral to the pubic tubercle in an 80-year-old woman with vomiting	Obstructed femoral hernia
Strangulated hernia without obstruction	Richter's hernia
Soft bluish groin lump that disappears on lying down, with a cough thrill	Saphena varix
Thin older woman with SBO and pain down the inner thigh	Obturator hernia (Howship–Romberg sign)
Lateral lower abdominal pain with a vague lump at the edge of rectus	Spigelian hernia
Intermittent colicky pain 2 years after gastric bypass	Internal hernia
Bulge beside a colostomy making the bag leak	Parastomal hernia
Bulge in a laparotomy scar a year after a wound infection	Incisional hernia
Midline ridge on sitting up after three pregnancies, no defect	Divarication of the recti
Tender abdominal wall mass that persists on tensing the muscles, on warfarin	Rectus sheath haematoma
Painful lump in a caesarean scar that swells with each period	Scar endometriosis
Hard nodule at the umbilicus in a woman with weight loss	Sister Mary Joseph nodule (metastasis)
Leaking fluid from an umbilical hernia in cirrhosis with ascites	Ruptured umbilical hernia -emergency
Chest pain, retching without vomiting and an NG tube that won't pass	Gastric volvulus in a paraoesophageal hernia
Retention of urine after laparoscopic inguinal hernia repair	Post-operative urinary retention
Burning groin pain for 6 months after mesh repair	Chronic post-herniorrhaphy pain (nerve entrapment)
Small shrunken testis after hernia repair	Ischaemic orchitis and atrophy

Exam-style Scenarios

1. An 82-year-old thin woman has vomited for 2 days with colicky abdominal pain and distension. She has had no previous surgery. There is a small, firm, tender lump in her right groin below and lateral to the pubic tubercle.
Answer: Obstructed (possibly strangulated) right femoral hernia.

• Resuscitate -IV fluids, analgesia, NG tube, bloods including lactate; consent and urgent theatre.
• Don't attempt forcible reduction; emergency repair with inspection of the bowel and resection if non-viable.
• Consider CT if the diagnosis is uncertain, but don't delay surgery for imaging if strangulation is likely.

2. A 58-year-old man has a right groin bulge for a year that goes away when he lies down. It causes mild aching after a long day at work. He smokes and has a chronic cough.
Answer: Symptomatic reducible right inguinal hernia.

• Offer elective repair (open mesh or laparoscopic); explain risks -chronic pain, recurrence, haematoma, retention, testicular problems.
• Optimise before surgery -stop smoking, investigate and treat the cough (chest X-ray if indicated), check for prostate symptoms and constipation.
• Advise on warning signs of incarceration or strangulation while waiting.

3. A 70-year-old man had a laparotomy for a perforated diverticulum 18 months ago, complicated by a wound infection. He now has a large bulge in his midline scar that is reducible. BMI 38, smoker, HbA1c 78.
Answer: Incisional hernia -optimise before elective repair.

• Weight loss, smoking cessation and better diabetes control reduce complications and recurrence.
• CT to assess the defect size and any other defects; consider an abdominal binder meanwhile.
• Mesh repair (open or laparoscopic, or complex reconstruction if very large) once optimised; urgent surgery if it becomes painful and irreducible.

4. A 7-week-old baby boy born at 32 weeks has a swelling in his left groin that appears when he cries and goes away when he settles.
Answer: Indirect inguinal hernia in a premature infant.

• Refer promptly to paediatric surgery for herniotomy -high risk of incarceration in infants.
• Teach parents the warning signs -a hard, tender swelling that doesn't go back, vomiting, distress -seek urgent help.
• Check the other side and the testes (undescended testis is more common in prematurity).

Key Points

• A hernia can be reducible, incarcerated, obstructed or strangulated; strangulation is an emergency.
• Richter's hernia can strangulate without obstruction.
• Inguinal hernias lie above and medial to the pubic tubercle; femoral hernias below and lateral.
• Indirect inguinal hernias pass lateral to the inferior epigastric vessels; direct ones medial (Hesselbach's triangle).
• Children's inguinal hernias are indirect -repair promptly, urgently in infants.
• Minimally symptomatic inguinal hernias in men can be watched; symptomatic ones repaired.
• All femoral hernias should be repaired -high strangulation risk; common in older women.
• Always examine hernial orifices in bowel obstruction.
• Obturator hernia -thin older woman, SBO, inner thigh pain (Howship–Romberg).
• Don't forcibly reduce a tender hernia; gentle taxis only for non-tender recent incarceration.
• Laparoscopic repair suits bilateral and recurrent inguinal hernias and women.
• Chronic groin pain and recurrence are the main long-term risks of repair.
• Optimise smoking, weight, cough and diabetes before elective repair.
• Divarication of the recti is not a hernia and doesn't strangulate.
• Rectus sheath haematoma -tender mass on anticoagulants, persists on tensing the muscles.

Guidelines and Further Reading

• HerniaSurge Group: International guidelines for groin hernia management
• European Hernia Society: Guidelines on incisional, umbilical, epigastric and parastomal hernias
• Royal College of Surgeons of England: Commissioning guide -groin hernia
• NICE: Laparoscopic surgery for inguinal hernia repair
• BNF -for current doses