Incisional Hernia
Incisional hernia occurs through a previous surgical incision site. It affects approximately 10-15% of laparotomy wounds and is a common late surgical complication.
Key Facts
Occurs in 10-15% of laparotomy wounds; up to 23% in emergency laparotomies Risk factors: Wound infection (strongest modifiable factor), obesity, emergency surgery, vertical midline incision, malnutrition, immunosuppression, chronic cough Usually presents as a bulge at the previous incision site, increasing with straining Can cause significant morbidity: Pain, cosmetic concern, bowel obstruction, strangulation Mesh repair (open or laparoscopic) is superior to primary suture repair — recurrence ~10-15% vs ~30-50% Laparoscopic repair: Lower wound infection rate and shorter recovery; recommended by NICE (IPG134) Incarceration and strangulation can occur — same principles as other hernias Prevention: Mass closure of laparotomy (Jenkins rule — suture length:wound length ≥4:1), avoid wound infection
Overview
Key Facts
Incisional hernias are a common and significant complication of abdominal surgery. Prevention through optimal wound closure technique and post-operative care is paramount.
Epidemiology
Affects ~10-15% of all laparotomy wounds. Incidence is higher after emergency surgery (~23%), wound infection (~30%), and obesity. Most develop within 1-3 years of surgery but can present decades later.
Aetiology
Risk factors:
- Surgical: Wound infection (strongest modifiable factor), vertical midline incision, emergency surgery, re-operation, drain sites
- Patient: Obesity, malnutrition, diabetes, smoking, chronic cough/COPD, immunosuppression, connective tissue disorders, age >60
- Technical: Inadequate closure technique, inappropriate suture material
Pathophysiology
- Failure of fascial healing at the surgical incision site
- Increased intra-abdominal pressure (obesity, chronic cough, ascites) exacerbates defect
- Progressive enlargement over time as abdominal contents herniate through the defect
- Loss of domain: Large hernias → abdominal contents permanently outside abdomen → respiratory compromise, loss of abdominal domain
Clinical Presentation
Typical Presentation
- Bulge at previous surgical incision, increasing with standing/straining
- Reducible in most cases
- May be asymptomatic or cause pain, dragging sensation
- Cosmetic concern, especially with large hernias
Complications
- Incarceration → obstruction → strangulation (same spectrum as other hernias)
- Skin complications over large hernias (ulceration, dermatitis)
- Respiratory compromise with very large hernias (loss of domain)
Red Flags
- Tender, irreducible incisional hernia — strangulation
- Signs of bowel obstruction
- Overlying skin changes — compromise of contents
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Seroma | Fluctuant, non-reducible, post-operative, no cough impulse | US |
| Wound abscess | Tender, warm, erythematous, may discharge | US, blood cultures |
| Rectus diastasis | Midline bulge on sitting up, no fascial defect | Clinical, CT |
| Malignant deposit | Hard, non-reducible, growing | CT, biopsy |
| Subcutaneous lipoma | Soft, non-tender, no cough impulse | Clinical |
Diagnosis / Investigation
Bedside
- Clinical examination: Usually diagnostic; examine lying and standing
Imaging
- CT abdomen: Defines defect size, contents, complications, loss of domain
- Ultrasound: If clinical uncertainty
- CT is essential for surgical planning in large or complex hernias
Management
Conservative
- Watchful waiting: For asymptomatic small hernias in high-risk surgical patients
- Abdominal binder: Symptomatic relief; does not prevent enlargement or complications
- Optimise risk factors: Weight loss, smoking cessation, glycaemic control, treat chronic cough
Surgical
- Mesh repair is superior to primary suture repair
- Open mesh repair: Onlay, sublay (retromuscular — Rives-Stoppa), or underlay (intraperitoneal)
- Sublay (retromuscular) placement has lowest recurrence rate
- Laparoscopic repair (IPOM — intraperitoneal onlay mesh): Lower wound infection, faster recovery; NICE IPG134
- Component separation: For large hernias with loss of domain — allows tension-free closure
- Botulinum toxin A: Pre-operative injection to relax lateral abdominal wall muscles → aids closure of large defects (progressive pneumoperitoneum is an alternative)
Emergency
- Strangulated incisional hernia → emergency surgery, possible bowel resection
Referral Criteria
- Symptomatic incisional hernia — surgical referral
- Enlarging hernia — surgical referral
- Complicated hernia — emergency surgery
Prognosis
- Mesh repair recurrence: ~10-15% (vs ~30-50% for primary suture repair)
- Surgical site infection: ~5-10% (mesh-related)
- Chronic pain: ~5-10% post-repair
- Loss of domain: Complex surgical challenge; higher morbidity
- Prevention: Optimal primary wound closure technique is the most effective strategy
Other Relevant Information
Jenkins Rule for Laparotomy Closure
| Principle | Detail |
|---|---|
| Suture:wound length ratio | ≥4:1 |
| Suture type | Slowly absorbable (e.g., PDS/looped PDS) or non-absorbable |
| Bite size | ≥1cm from wound edge |
| Stitch interval | ≤1cm apart |
| Technique | Mass closure (all layers except skin and peritoneum) |
| Goal | Small bites technique — reduces incisional hernia rate by ~30% (STITCH trial) |