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Hernia: A Comprehensive Overview

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1. Definition

• Reducible hernia – contents can be returned to the original cavity spontaneously or with manual pressure
• Irreducible / Incarcerated hernia – contents are trapped and cannot be reduced; may cause obstruction
• Strangulated hernia – vascular supply to the herniated contents is compromised; a surgical emergency

Hernias of all types are second only to adhesions as the most frequent causes of intestinal obstruction in western countries. — Mulholland and Greenfield's Surgery, 7e

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2. Classification / Types

By Location

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3. Causes & Pathophysiology

Indirect Inguinal Hernia

• Failure of closure of the processus vaginalis (a peritoneal diverticulum that accompanies the testis into the scrotum during fetal development)
• Explains the high incidence in premature infants (closure normally occurs before birth)
• By definition, all congenital hernias in children are indirect

Acquired Hernias (Direct, Femoral, Ventral)

• Weakness or defects in the abdominal wall fascia/musculature due to:
  • Degenerative changes in connective tissue (collagen metabolism defects)
  • Prior surgery → incisional hernias
  • Infection → poor wound healing
  • Increased intra-abdominal pressure (chronic straining, obesity, pregnancy)

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4. Risk Factors

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5. Symptoms & Clinical Presentation

Reducible Hernia

• Groin or abdominal bulge that appears with standing, coughing, straining (Valsalva)
• Disappears on lying down or with manual pressure
• Dull ache or pressure sensation at the site
• May be asymptomatic and noticed incidentally

Incarcerated Hernia

• Firm, tender, non-reducible bulge
• Pain at the hernia site
• Signs of intestinal obstruction: nausea, vomiting, abdominal distension, cessation of flatus/stool
• In infants: fussiness, irritability, firm groin mass

Strangulated Hernia

• Severe, constant pain at the hernia site
• Overlying skin changes: erythema, edema
• Systemic signs: fever, tachycardia, toxic appearance, peritonitis, sepsis
• Vomiting and complete obstruction
• Surgical emergency — bowel necrosis may follow rapidly

"Is the hernia easily reducible or incarcerated? Is the vascular supply to the bowel strangulated? A patient with an easily reducible hernia can be discharged safely for outpatient follow-up and elective repair, whereas an acutely incarcerated and strangulated hernia is [a surgical emergency]." — Roberts and Hedges' Clinical Procedures in Emergency Medicine

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6. Diagnosis

Clinical Assessment (Primary)

• History: location, onset, aggravating factors, obstructive symptoms
• Physical examination: Standing and supine; Valsalva maneuver to bring out the bulge
  • Palpate the inguinal canal by invaginating scrotal skin
  • Impulse felt at fingertip = indirect hernia; at pulp of finger = direct hernia
  • Assess reducibility and tenderness

Laboratory Studies

• Routine CBC, electrolytes, urinalysis — minimal diagnostic value for uncomplicated hernia; useful for pre-operative clearance or ruling out alternative diagnoses

Imaging

CT is the best-performing radiographic test for hernia diagnosis and can identify uncommon hernia types as well as demonstrate incarceration and strangulation. — Tintinalli's Emergency Medicine

Ultrasound Signs of Strangulation:

• Free fluid in the hernia sac
• Hyperechoic fat
• Wall thickening of herniated bowel
• Absence of peristalsis
• Loss of venous/lymphatic Doppler signal

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7. Treatment

Conservative (Non-Surgical)

• Watchful waiting is acceptable for asymptomatic or minimally symptomatic reducible inguinal hernias in men — risk of incarceration is low (~0.2%/year)
• Truss (mechanical support) — not recommended as definitive treatment; does not prevent progression
• Weight loss, cough treatment to reduce intra-abdominal pressure
• Note: Spontaneous resolution does NOT occur in children after infancy; children with inguinal hernia should undergo elective repair

Emergency Treatment (Incarcerated/Strangulated)

1. Attempted manual reduction (taxis) — for incarcerated hernias WITHOUT signs of strangulation:
   • NPO status
   • Adequate IV narcotic analgesia
   • Cold packs to reduce swelling
   • Grasp and elongate hernia neck with one hand; apply steady pressure proximally at the fascial defect
   • One or two attempts; consult surgery if unsuccessful
2. If strangulated: No reduction attempts; immediate surgical consultation; IV antibiotics; fluid resuscitation; urgent OR
3. Beware "reduction en masse" — apparent reduction but bowel remains incarcerated within the sac inside the peritoneal cavity; persistent pain despite apparent reduction requires imaging

Surgical Treatment

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8. Hernioplasty

Definition

"The herniorrhaphy performed in children involves closing off the patent processus vaginalis. This is to be contrasted with the hernioplasty performed in adults, which requires reconstruction of the inguinal floor." — Schwartz's Principles of Surgery, 11e

Open (Anterior) Approaches

A. Lichtenstein Tension-Free Repair (Gold Standard for Adults)

• A flat polypropylene mesh is placed over the inguinal floor and sutured into position, creating a tension-free repair
• Mesh covers Hesselbach's triangle and extends to the internal ring
• A slit in the mesh allows passage of the spermatic cord and creates a new internal ring
• Advantages: low recurrence (<1%), low tension, can be done under local anesthesia
• Current recommendation: open tissue repair preferred in contaminated/emergency cases; mesh reserved for elective/recurrent repairs

B. Plug and Patch (Rutkow-Robbins / Gilbert)

• A modification of Lichtenstein; a 3D polypropylene plug is placed into the internal inguinal ring (for indirect hernia) or the direct defect, followed by a flat mesh patch over the inguinal floor

C. Bassini Repair (Tissue — Historical)

• Classic tissue repair: transversalis fascia, transversus abdominis, and internal oblique muscles are sutured to the inguinal ligament
• Higher tension and recurrence compared to mesh repairs

D. Shouldice Repair (Best Tissue Repair)

• Four-layer running suture repair of the posterior wall (transversalis fascia)
• Best tissue repair technique; low recurrence in specialized centers
• Uses no mesh; preferred when mesh is contraindicated

E. McVay (Cooper's Ligament) Repair

• Transversalis fascia sutured to Cooper's ligament; also repairs femoral hernia
• Requires a relaxing incision to reduce tension

F. Desarda Repair (Mesh-Free)

• Strip of external oblique aponeurosis sutured to the inguinal ligament as a mesh substitute
• Introduced 2001; mesh-free option

Laparoscopic (Posterior) Approaches

Mesh Considerations

• Synthetic permanent mesh (polypropylene): most common; excellent long-term results
• Biologic mesh: for contaminated fields (bowel resection, infection)
• In contaminated/emergency cases: mesh use is controversial; tissue repair preferred to avoid mesh infection
• Risk with mesh: infection, chronic groin pain, mesh migration, ischemic orchitis (0.2–1%), seroma

Key Complications of Hernia Repair

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Summary Table

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