Hernia - A Comprehensive Clinical Overview

Definition

Classification

By Reducibility / Clinical State

The risk of strangulation depends heavily on the size of the hernia neck. Femoral hernias strangulate in up to 40–50% of cases at presentation, while incisional hernias strangulate in only ~2%. Among all patients with small bowel obstruction from hernia, intestinal ischaemia occurs in up to 75% and necrosis in over 25%. - Sleisenger & Fordtran's GI and Liver Disease; Maingot's Abdominal Operations

By Location

External (Abdominal Wall) Hernias

• Inguinal (direct and indirect)
• Femoral
• Umbilical / Paraumbilical
• Epigastric
• Spigelian
• Incisional (ventral)
• Obturator
• Lumbar (Petit's triangle, Grynfeltt-Lesshaft)
• Perineal
• Sciatic

Internal Hernias

• Congenital: paraduodenal, through the foramen of Winslow
• Iatrogenic: after Roux-en-Y gastric bypass (Petersen's defect), colectomy, pancreaticoduodenectomy - Maingot's

Inguinal Hernia (Most Common)

Epidemiology

• Most common hernia overall; ~10:1 male to female predominance
• More frequent on the right side
• A patient with one inguinal hernia has a 50% lifetime risk of developing one on the other side - Bailey & Love

Anatomy of the Inguinal Canal

• Anteriorly: external oblique aponeurosis
• Posteriorly: transversalis fascia (reinforced medially by the conjoint tendon)
• Superiorly: arching fibres of internal oblique and transversus abdominis, forming the conjoint tendon
• Inferiorly: inguinal ligament (rolled-under edge of external oblique)

Types

Indirect (Lateral / Oblique) Inguinal Hernia

• Passes through the deep inguinal ring lateral to the inferior epigastric vessels
• Travels obliquely through the inguinal canal in the path of the processus vaginalis
• Can descend into the scrotum (scrotal hernia)
• Can be congenital (due to a patent processus vaginalis, failure of closure before birth) or acquired
• All paediatric inguinal hernias are indirect by definition
• Higher risk of strangulation than direct hernias due to a narrower neck

Direct (Medial) Inguinal Hernia

• Always acquired - due to weakness in the posterior wall medial to the inferior epigastric vessels
• Protrudes through Hesselbach's triangle (boundaries: inferior epigastric vessels laterally, lateral border of rectus abdominis medially, inguinal ligament inferiorly)
• Broad base - rarely strangulates
• More common in elderly men
• The bladder can be pulled into a direct hernia

Sliding Hernia

• An indirect hernia where a retroperitoneal organ (e.g., sigmoid colon on the left, caecum on the right) forms part of the wall of the hernia sac
• Needs careful identification at surgery to avoid bowel injury during sac excision - Bailey & Love

Pantaloon (Saddle-bag) Hernia

• Combined direct and indirect hernia straddling the inferior epigastric vessels, creating a "pantaloon" shape

Femoral Hernia

Anatomy

• Protrudes through the femoral canal - a small space just medial to the femoral vein, bounded by:
  • Laterally: femoral vein
  • Anteriorly: inguinal ligament
  • Posteriorly: pectineal (Astley Cooper's) ligament
  • Medially: lacunar (Gimbernat's) ligament - has a sharp, unyielding edge that impedes reduction
• Appears below and lateral to the pubic tubercle (inguinal hernia is above and medial)

Key Clinical Points

• Less common than inguinal hernia
• More common in women (wider female pelvis enlarges the femoral canal)
• Commonly seen in thin, elderly women
• Easily missed on examination
• ~50% present as an emergency with strangulation - highest strangulation rate of all hernias
• The femoral pulse is lateral to the hernia; a saphena varix (enlarged saphenous vein) is an important differential - it disappears on lying down and has a fluid thrill - Bailey & Love

Umbilical Hernia

In Children

• Occurs in up to 10% of infants; higher in premature babies and Black infants (8x higher)
• Increases in size with crying; rarely strangulates under age 3
• 95% resolve spontaneously by age 2 - conservative management is appropriate
• Surgical repair is indicated if it persists beyond age 2 - Bailey & Love

In Adults

• Predisposed by obesity, pregnancy, cirrhosis with ascites - conditions that increase intra-abdominal pressure or thin the linea alba
• The neck is often narrow, making strangulation common (~60% at emergency surgery)
• Umbilical hernias account for ~15% of emergency hernia surgery - Sleisenger & Fordtran's
• Paraumbilical hernias (adjacent to but not exactly at the umbilicus) are now classified together with umbilical hernias under current guidelines

Incisional (Ventral) Hernia

• Occurs through a weakness at a previous surgical wound
• Risk factors: wound infection, obesity, malnutrition, steroid use, poor surgical technique, raised intra-abdominal pressure
• Usually has a wide neck - relatively low strangulation rate (~2%) compared with inguinal/femoral types
• Management: surgical repair with mesh (open or laparoscopic). Larger defects require component separation techniques - Bailey & Love; Maingot's

Other Notable Hernias

Diagnosis

Clinical

• History: a groin, abdominal, or other lump that increases with standing, coughing, or straining; reducible on lying down; dragging or aching discomfort
• Examination: impulse on coughing, reducibility, site relative to anatomical landmarks (pubic tubercle, ASIS), transillumination (to differentiate from hydrocele)

Investigations

• Usually clinical - imaging is rarely needed for straightforward hernias
• Ultrasound: useful for occult hernias, differentiating groin masses; limited sensitivity in supine patients (hernia may reduce)
• CT scan: most useful for obese patients, suspected internal hernias, incarcerated/strangulated hernias, or preoperative planning for complex abdominal wall hernias
• MRI: useful for occult or sports hernia (athletic pubalgia) - Bailey & Love
• Herniography (contrast injection into the peritoneum) is rarely used today

Principles of Surgical Repair

Terminology

• Herniorrhaphy: repair by suture closure of the defect alone (used in children, where the anatomy is normal)
• Hernioplasty: reconstruction of the weakened abdominal wall (needed in adults)

Open Repairs (Inguinal)

Mesh plug repairs (e.g., Perfix plug) are not recommended by the 2018 European Hernia Society (EHS) guidelines due to risks of meshoma and migration into adjacent structures (bladder, bowel, vessels). - Bailey & Love

Laparoscopic Repairs

Femoral Hernia Repair Approaches

• Lockwood (low approach): through the groin below the inguinal ligament; useful for elective cases
• Lotheissen (high approach): via the inguinal canal; risk of weakening the canal
• McEvedy (high extraperitoneal approach): preferred for strangulated femoral hernias as it provides access for bowel resection

Complications of Hernia and Hernia Repair

Complications of Untreated Hernia

• Incarceration (irreducibility)
• Intestinal obstruction
• Strangulation and bowel necrosis
• Perforation, peritonitis, sepsis

Complications of Surgery

• Immediate: bleeding, haematoma, urinary retention, wound complications, femoral nerve block (from local anaesthetic)
• Short-term: seroma (common after laparoscopic repair; may mimic recurrence), wound infection, testicular swelling
• Long-term:
  • Recurrence: target <5% at 5 years in specialist centres; mesh repairs have lower rates than suture alone
  • Chronic pain (>3 months): affects up to 20% after open mesh repair, less after laparoscopic repair; can be neuralgic (nerve injury or irritation from mesh/suture), somatic, or visceral
  • Mesh complications: infection, migration, erosion into viscera, meshoma formation
  • Ischaemic orchitis / testicular atrophy: rare but serious; results from damage to the vas deferens or testicular vessels - Bailey & Love

Specialist hernia surgeons have demonstrably lower recurrence and chronic pain rates regardless of the technique used. - Bailey & Love, 28th Ed.

Special Situations

Paediatric Inguinal Hernia

• All congenital; all indirect; due to patent processus vaginalis
• High incarceration risk in infants due to narrow internal ring
• Repaired by herniorrhaphy (ligation of the patent processus vaginalis) without mesh
• If incarcerated but not strangulated: attempt gentle manual reduction under sedation, then repair within 24 h
• Emergency repair if strangulated (may require laparotomy + bowel resection) - Schwartz's Surgery, 11th Ed.

Internal Hernia After Laparoscopic Gastric Bypass

• Incidence 0.2-3% (much higher than with open approach)
• Due to lack of adhesion formation and marked weight loss reducing mesenteric fat (enlarging potential hernia openings)
• Petersen's defect: most common site (posterior to the alimentary limb)
• Presents with intermittent periumbilical pain, nausea, vomiting; CT may be non-diagnostic as the hernia can spontaneously reduce
• All mesenteric defects should be closed at the time of initial RYGB - Maingot's Abdominal Operations

Recent Evidence (2024-2025)

• A systematic review on incarcerated/strangulated inguinal hernias (EAST Practice Management Guideline, 2025) provides updated guidance on urgent surgical intervention, emphasising early operative management for strangulated hernias. [PMID: 40671180]
• A 2025 systematic review on hiatus hernia classification highlights ongoing variability in classification systems for hiatal hernias, emphasising the need for standardisation. [PMID: 40485346]

Lichtenstein Tension-Free Inguinal Hernia Repair

Step-by-Step Surgical Technique Guide

Principle: Introduced by Dr. Irving Lichtenstein in 1984, this tension-free technique reinforces the posterior wall of the inguinal canal with a flat polypropylene mesh, eliminating the tissue tension that caused pain and high recurrence rates with earlier suture repairs. It is currently the most widely performed inguinal hernia repair in the world.

Pre-operative Preparation

• Inject a field block along the line of incision (subcutaneous and deep to external oblique)
• Infiltrate around the pubic tubercle
• Block the ilioinguinal and iliohypogastric nerves medial to the ASIS

STEP 1 - Skin Incision

• Mark an oblique incision 2 cm above and parallel to the inguinal ligament, running from just medial to the anterior superior iliac spine (ASIS) to just lateral to the pubic tubercle
• Length: 6-8 cm
• Incise skin and subcutaneous fat; ligate or cauterise superficial epigastric and superficial circumflex iliac veins to control bleeding

Current Surgical Therapy 14e

STEP 2 - Exposure of External Oblique Aponeurosis

• Deepen dissection through Camper's and Scarpa's fascia to reach the shiny, white external oblique aponeurosis
• Identify the external (superficial) inguinal ring medially - an inverted V-shaped defect in the aponeurosis
• Create superior and inferior flaps of skin and subcutaneous tissue to expose:
  • The full width of the external oblique
  • The shelving edge of the inguinal ligament inferiorly
  • The aponeurotic portion of internal oblique superiorly

STEP 3 - Opening the Inguinal Canal

• Using Metzenbaum scissors, incise the external oblique along the direction of its fibres, starting at the external ring and extending laterally beyond the level of the deep inguinal ring (superolateral direction)
• This opens the anterior wall of the inguinal canal and exposes its contents
• Evert the two flaps of external oblique aponeurosis and hold them with retractors

Bailey and Love's Short Practice of Surgery, 28th Ed.

STEP 4 - Nerve Identification and Protection ⚠️

• All three nerves can be identified in 70-90% of cases with careful dissection
• Identification and protection reduces chronic pain incidence to <1% in experienced hands
• If a nerve is trapped, damaged, or likely to be compressed by mesh: perform elective neurectomy at that time (resect a segment and bury the end in muscle)

Lichtenstein technique - 10 recommendations, PMC11297121 (2024)

STEP 5 - Isolation of the Spermatic Cord

• At the level of the pubic tubercle, encircle the spermatic cord (in men) or the round ligament (in women) with a Penrose drain for easy retraction
• Gently separate the cord from the floor (posterior wall) of the canal by blunt dissection

STEP 6 - Hernia Sac Dissection and Management

Indirect Hernia Sac

• The indirect sac lies on the anterolateral surface of the cord
• Divide overlying cremasteric fibres to expose the sac fully
• Separate the sac from the vas deferens and testicular vessels with careful sharp/blunt dissection - avoid injury to the vas
• For small/moderate sacs: simply ligate the sac at the neck with an absorbable suture and excise the distal portion, or invert the sac through the deep ring (no excision needed)
• For large/scrotal sacs: do not attempt full dissection to the neck (risk of haematoma, ischaemic orchitis). Divide the sac at mid-canal, oversew the proximal end, and leave the distal sac in situ (open or closed)

Direct Hernia Sac / Posterior Wall Weakness

• Inspect the posterior wall (floor of the canal) medial to the inferior epigastric vessels
• A direct defect is imbricated or inverted by plication of the transversalis fascia with an absorbable suture
• Unlike suture repairs, there is no attempt to formally reconstruct the floor - the mesh will reinforce it

Current Surgical Therapy 14e; Bailey & Love 28th Ed.

STEP 7 - Mesh Positioning

• Medially: overlap the pubic symphysis by ≥2 cm
• Superiorly: extend 3-4 cm above the inguinal triangle (conjoint tendon)
• Laterally: extend 5-6 cm beyond the internal inguinal ring
• The mesh lies posterior to the spermatic cord, between the cord and the posterior canal wall

• Divide the mesh along its long axis from the lateral end, creating two tails:
  • Wider upper tail (approximately 2/3 of the mesh width)
  • Narrower lower tail (approximately 1/3)
• These tails will recreate the deep inguinal ring around the cord

STEP 8 - Mesh Fixation

Zone 1 - Medial Fixation (Pubic Tubercle)

• Secure the medial end of the mesh to the aponeurotic tissue overlying the pubic tubercle with 1-2 interrupted absorbable sutures
• Do NOT stitch to the periosteum of the pubic bone (risk of osteitis)
• Overlap the pubic tubercle by at least 2 cm to prevent medial recurrence

Zone 2 - Inferior Fixation (Inguinal Ligament)

• Using a continuous non-absorbable monofilament suture (e.g., 2-0 prolene), sew the lower edge of the mesh to the inguinal ligament, passing the needle through the ligament 3-4 times
• Run the suture from the pubic tubercle laterally to just past the deep inguinal ring
• Keep the mesh slightly relaxed (dome-shaped) rather than pulled taut - this compensates for mesh contraction and prevents recurrence under intra-abdominal pressure

Zone 3 - Superior Fixation (Internal Oblique / Conjoint Tendon)

• Place interrupted absorbable sutures (NOT running suture) to fix the upper edge of the mesh to the aponeurosis of the internal oblique or the conjoint tendon
• Restricted to medial to the deep inguinal ring - avoid suturing laterally where the iliohypogastric nerve courses
• Sutures should be loosely tied to prevent tissue necrosis and nerve entrapment

Alternative fixation: Cyanoacrylate (surgical glue) or self-adherent mesh - randomised trials (Matikainen 2017, 2021) show equivalent recurrence and chronic pain rates vs. suture fixation, with potentially faster operative time. - Current Surgical Therapy 14e

STEP 9 - Recreating the Internal (Deep) Inguinal Ring

• Cross the two mesh tails behind the spermatic cord (upper tail anterior to lower tail)
• Secure the tails with a single interrupted non-absorbable suture to snugly reform the internal ring around the cord
• The reconstructed ring should admit just the cord without compression - admit a fingertip alongside the cord to confirm adequate laxity
• The lateral portions of the tails lie flat beneath the external oblique

Crossing the tails behind the cord (rather than in front) prevents lateral recurrence. This is one of Lichtenstein's original five operative principles.

STEP 10 - Wound Closure

1. External oblique aponeurosis: continuous 2-0 absorbable suture, reconstituting the inguinal canal and re-forming the external ring (should admit just the cord)
2. Scarpa's fascia: interrupted 3-0 absorbable suture (reduces dead space and wound seroma)
3. Skin: subcuticular 3-0 absorbable suture or surgical staples

Critical Technical Points Summary

Post-operative Care

• Day surgery in the majority of cases
• Mobilise and eat/drink same day
• Return to light activity: 48-72 hours
• Return to desk work: 1-2 weeks
• Return to manual/heavy labour: 4-6 weeks
• Avoid constipation and straining (stool softeners if needed)
• Scrotal support / ice pack for swelling in the first 24-48 hours

Complications to Counsel Pre-operatively