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Myopectineal Orifice (MPO) of Fruchaud

Definition and Historical Background

• Sabiston Textbook of Surgery, p. 1683

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Anatomy

• Lateral (muscular) space - transmits the iliopsoas complex and femoral nerve
• Medial (vascular) space - transmits the femoral artery, vein, and the femoral canal (the potential space for femoral hernias)

• Mulholland and Greenfield's Surgery, p. 3632

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Hernia Types Through the MPO

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Surgical Significance: The Critical View of the MPO

The 9 Steps to Achieve the Critical View:

1. Identify and dissect the pubis across the midline and Cooper's ligament (Zone 2)
2. Rule out a direct hernia by clearing fat from Hesselbach's triangle
3. Dissect at least 2 cm between Cooper's ligament and the bladder (Space of Retzius)
4. Rule out femoral hernia by dissecting between Cooper's ligament and the external iliac vein (Zone 3)
5. Thoroughly dissect peritoneum and indirect hernia sac off the spermatic cord/round ligament
6. Identify the vas deferens and gonadal vessels - parietalize the cord (reduce the indirect sac)
7. Dissect peritoneum laterally toward ASIS to create Space of Bogros (Zone 1 lateral space)
8. Visualize the entire MPO including all critical structures in Zones 1, 2, and 3
9. Only then - place mesh (minimum 15 x 10 cm, no creases or folds)

• Fischer's Mastery of Surgery, 8th ed., p. 6101

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Mesh Coverage

• Medial: At least to the pubic symphysis (across to contralateral Cooper's ligament if direct hernia present)
• Superior: 3-4 cm above the internal inguinal ring onto the anterior abdominal wall
• Inferior: 1-2 cm below the pubis, into the Space of Retzius
• Lateral: Lying against the psoas muscle
• Minimum size: 15 x 10 cm (some guidelines recommend 14 x 11 cm or larger)
• The mesh must not be split around the cord

• Mulholland and Greenfield's Surgery, p. 3814
• Sabiston Textbook of Surgery, p. 1685

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Key Anatomical Hazards Within the MPO

• Corona mortis - aberrant obturator artery/vein crossing Cooper's ligament, connecting inferior epigastric and obturator vessels; can bleed catastrophically if injured
• Triangle of Doom - between vas deferens (medially) and gonadal vessels (laterally); contains the external iliac vessels - no staples or tacks here
• Triangle of Pain - lateral to the gonadal vessels; contains the femoral branch of the genitofemoral nerve and the lateral femoral cutaneous nerve - no fixation here
• Genitofemoral nerve (genital and femoral branches) run posterior to the transversalis sling (TS) on the surface of the psoas
• Femoral nerve runs deep within the psoas, emerging laterally beneath the inguinal ligament

Inguinal Hernia - Basic to Detailed

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1. What Is a Hernia?

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2. Overview: Sites of Abdominal Wall Hernias

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3. Anatomy of the Inguinal Canal

Walls of the Inguinal Canal

Rings

• Deep (internal) inguinal ring: A defect in the transversalis fascia. Lies at the midpoint of the inguinal ligament (midway between ASIS and pubic tubercle), ~2-3 cm above the femoral artery pulse. The inferior epigastric vessels run just medial to this ring - this is the key landmark distinguishing direct from indirect hernias.
• Superficial (external) inguinal ring: An inverted V-shaped defect in the external oblique aponeurosis, just above and medial to the pubic tubercle.

Contents of the Inguinal Canal

• Vas deferens
• Testicular artery and veins (pampiniform plexus)
• Cremasteric artery and vein
• Artery to vas deferens
• Genital branch of the genitofemoral nerve
• Cremasteric muscle fibers (from internal oblique)
• Lymphatics from the testis

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4. Hesselbach's Triangle

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5. Types of Inguinal Hernia

Indirect (Lateral / Oblique) Inguinal Hernia

• Exits the peritoneum lateral to the inferior epigastric vessels, through the deep inguinal ring
• Follows the path of testicular descent (along the processus vaginalis)
• The hernia sac is a constituent of the spermatic cord - covered by internal spermatic fascia, cremasteric fascia, and external spermatic fascia
• Can descend all the way into the scrotum (inguinoscrotal hernia)
• Can be congenital (patent processus vaginalis) or acquired
• More common in young males and on the right side (right testis descends later)

Direct (Medial) Inguinal Hernia

• Exits medial to the inferior epigastric vessels, directly through the thinned transversalis fascia in Hesselbach's triangle
• Does NOT enter the inguinal canal - pushes directly forward and out of the superficial ring
• The hernia sac lies adjacent to (not within) the spermatic cord
• Always acquired - due to progressive weakening of the abdominal wall
• More common in elderly males
• Broadly based - rarely strangulates (in contrast to indirect hernias)
• The bladder can be pulled into a direct hernia (sliding direct hernia)

Comparison Table

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6. Laparoscopic View of the Three Hernia Defects

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7. Special Types

Sliding Hernia

Pantaloon (Saddlebag) Hernia

Inguinoscrotal Hernia

Richter's Hernia

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8. Embryology - Why Indirect Hernias Occur

• This explains why all congenital hernias are indirect
• It explains the higher incidence in premature infants
• Partial closure produces a hydrocele; full patency produces a communicating hydrocele or hernia

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9. Detailed Topographic Anatomy of Inguinal Hernias

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10. Diagnosis

Clinical Diagnosis

• History: Groin bulge that appears on standing/coughing, reduces on lying down; aching or dragging discomfort; referred pain to the inner thigh or scrotum
• Inspection: Visible swelling in the groin - increases with Valsalva/coughing
• Deep ring occlusion test: Reduce the hernia, apply finger pressure over the deep ring (midpoint of inguinal ligament). Ask the patient to cough:
  • Hernia controlled = indirect (lateral)
  • Hernia appears medially despite pressure = direct

Differentiating Direct vs. Indirect Clinically

Diagram: Laparoscopic colour-coded defects (yellow=direct, blue=indirect, green=femoral)

Investigations

• Usually not required for straightforward cases
• Ultrasound: First-line imaging for equivocal groin swellings
• CT/MRI: Used when ultrasound is inconclusive, for large or complex hernias, or occult hernias

Differential Diagnosis of a Groin Swelling

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11. Classification

European Hernia Society (EHS) Classification

• P = Primary; R = Recurrent
• L = Lateral (indirect); M = Medial (direct); F = Femoral
• Defect size in fingerbreadths (~1.5 cm each): 1 = ≤1 fb; 2 = 1-3 fb; 3 = ≥3 fb

Nyhus Classification (anatomical)

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12. Complications

Irreducibility

Incarceration (Obstruction)

Strangulation

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13. Management

Non-surgical Management

• Watchful waiting is safe for asymptomatic or minimally symptomatic direct hernias, particularly in elderly patients
• Surgical trusses are not recommended (do not prevent complications, cause skin damage)

Herniotomy (Children Only)

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14. Open Surgical Repair

A. Bassini Repair (Historical, 1890)

B. Shouldice Repair

C. Lichtenstein Tension-Free Hernioplasty (Gold Standard Open Repair)

• Medial edge overlaps the pubic tubercle by 1.5-2 cm (fixed to anterior rectus sheath)
• Inferior margin fixed to the shelving edge of the inguinal ligament
• Upper edge fixed to the internal oblique
• Lateral tails wrapped around the spermatic cord at the internal ring

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

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15. Laparoscopic / Minimally Invasive Repair

TAPP (Transabdominal Preperitoneal)

• Abdominal cavity is entered first (pneumoperitoneum)
• Peritoneum incised above the hernia defects
• Preperitoneal space dissected to expose the entire myopectineal orifice (MPO)
• Large mesh (≥15×10 cm) placed in the preperitoneal space covering all three hernia spaces (direct, indirect, femoral)
• Peritoneum closed over mesh

TEP (Totally Extraperitoneal)

• The preperitoneal space is accessed directly without entering the peritoneal cavity
• A dissecting balloon creates the preperitoneal working space
• Dissection and mesh placement as for TAPP
• Preferred by many as the peritoneal cavity is not breached

Advantages of Laparoscopic vs. Open

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16. Nerves at Risk During Inguinal Hernia Repair

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17. Summary Flowchart

GROIN SWELLING
      |
Above inguinal ligament? → YES → INGUINAL HERNIA
      |
    Medial to IEV?         Lateral to IEV?
         ↓                        ↓
   DIRECT hernia           INDIRECT hernia
  (Hesselbach's Δ)        (through deep ring)
  Always acquired         Congenital or acquired
  Elderly, broad neck     Young, narrow neck
  Low strangulation       Higher strangulation
  risk                    risk

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Inguinal Hernia - Complete Reference (All Topics)

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PART 1: EPIDEMIOLOGY & RISK FACTORS

Risk Factors

• Chronic cough / COPD (strongly linked to direct hernias)
• Constipation / prostatism / bladder outlet obstruction
• Ascites
• Pregnancy
• Heavy lifting / physical exertion
• Valsalva maneuver

• Positive family history (8-fold increased lifetime risk)
• Low birthweight (<1500 g)
• Premature birth (patent processus vaginalis)
• Previous right lower quadrant incision (damages ilioinguinal nerve → weakens floor)
• Cigarette smoking (impairs collagen synthesis)

• Ehlers-Danlos syndrome
• Marfan syndrome
• Osteogenesis imperfecta
• α1-Antitrypsin deficiency
• Androgen insensitivity syndrome (very high incidence)

• Schwartz's Principles of Surgery, 11th ed., p. 1632

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PART 2: EMBRYOLOGY & PROCESSUS VAGINALIS

Degrees of Failure to Close

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PART 3: ANATOMY OF THE INGUINAL CANAL (DETAILED)

Layers of the Abdominal Wall at the Groin (Outside → In)

1. Skin
2. Scarpa's fascia (deep layer of superficial fascia)
3. External oblique muscle and aponeurosis
4. Internal oblique muscle
5. Transversus abdominis muscle
6. Transversalis fascia
7. Preperitoneal fat (Space of Bogros laterally; Space of Retzius medially)
8. Parietal peritoneum

Walls of the Inguinal Canal

Inguinal Canal Contents

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PART 4: HESSELBACH'S TRIANGLE (INGUINAL TRIANGLE)

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PART 5: TYPES OF INGUINAL HERNIA

The Key Landmark: Inferior Epigastric Vessels

• Hernia lateral to them = indirect
• Hernia medial to them = direct

Internal Hernia Openings (Posterior View)

• THIEME Atlas of Anatomy

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PART 6: NERVES OF THE INGUINAL REGION

Sensory Dermatomes - Why Nerve Injury Matters Clinically

Five Key Nerves

Triangle of Doom and Triangle of Pain

• Medial border: Vas deferens
• Lateral border: Gonadal vessels
• Apex: Deep inguinal ring
• Contains: External iliac artery and vein
• Risk: Catastrophic vascular injury if tacked during laparoscopic repair

• Superior border: Iliopubic tract
• Lateral border: Reflected peritoneum
• Superomedial: Gonadal vessels
• Contains: Femoral branch of GFN, lateral femoral cutaneous nerve, femoral nerve
• Risk: Nerve entrapment causing chronic neuropathic pain if tacked

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PART 7: PEDIATRIC INGUINAL HERNIA

Key Differences from Adults

Incarceration in Children

• Features: Firm, tense, non-reducible groin mass; irritability in infants; intestinal obstruction signs if bowel involved
• Management:
  1. Attempt gentle reduction (from below, toward internal ring) - may need light sedation
  2. If reduced: admit for observation, operate within 24h
  3. If cannot be reduced or strangulation suspected: emergency operation
  4. Strangulation: edematous, tender, erythematous swelling → emergency op with possible bowel resection

Bilateral Exploration in Children

• Incidence of bilateral PPV is ~60% at birth but falls with age
• Laparoscopic evaluation of the contralateral side through the hernia sac is now standard in many centers

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PART 8: CLINICAL FEATURES & EXAMINATION

Symptoms

• Groin bulge - appears on standing, coughing, straining; disappears on lying (reducible)
• Dragging ache in the groin / lower abdomen, worse during the day with activity
• Referred pain to inner thigh, scrotum, or labia (ilioinguinal nerve)
• Sudden onset of severe pain = complication (incarceration/strangulation)

Examination Sequence

• Reduce the hernia manually
• Apply firm pressure with finger over the deep inguinal ring (1 cm above midpoint of inguinal ligament)
• Ask patient to cough:
  • Controlled by pressure = Indirect (lateral) hernia
  • Not controlled, appears medially = Direct (medial) hernia

Important Clinical Signs

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PART 9: INVESTIGATIONS

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PART 10: COMPLICATIONS

1. Irreducibility

2. Incarceration (Obstruction)

• Sudden onset of pain in a previously painless hernia
• Tense, tender, irreducible swelling
• Signs of intestinal obstruction (vomiting, distension, absolute constipation)

3. Strangulation

• Severe constant pain (not just colicky)
• Hard, tender, irreducible swelling, overlying skin may be red
• Systemic signs: fever, tachycardia, peritonism
• No bowel sounds may be audible in the hernia

• Narrow neck (indirect > direct; femoral > inguinal)
• Long-standing irreducible hernia
• Elderly female (femoral hernia risk is highest)

1. Emergency operation
2. Assess bowel viability: warm pad for 5 minutes, check peristalsis, color, Doppler flow
3. Viable bowel: reduce
4. Non-viable bowel: resection + anastomosis (or Hartmann's for grossly contaminated field)
5. Hernia repair: Mesh placement remains acceptable in clean-contaminated fields (no gross enteric spillage); primary tissue repair for contaminated/dirty fields

4. Richter's Hernia

5. Maydl's Hernia (W-hernia)

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PART 11: SURGICAL REPAIR - ALL TECHNIQUES

Decision Framework

Inguinal hernia confirmed
          |
    ┌─────┴─────┐
 Elective    Emergency
(reducible)  (incarcerated/strangulated)
          |
   ┌──────┴──────┐
  Adult        Child
    |             |
  Mesh          Herniotomy
  repair     (sac ligation only)
    |
  ┌────────────────────┐
  Open                 Laparoscopic
  (Lichtenstein)       (TEP or TAPP)
  ↓                    ↓
  Local/spinal/GA      GA required
  ↓                    ↓
  Single hernia        Bilateral / recurrent
  No prior surgery     Previous open repair

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OPEN REPAIRS

A. Herniotomy (Pediatric Only)

B. Bassini Repair (1890)

• Open external oblique aponeurosis
• Mobilize spermatic cord
• Excise/reduce hernia sac
• Suture conjoint tendon to inguinal ligament from pubic tubercle to deep ring
• Reconstitutes the posterior wall under tension
• High recurrence rate (~15% in most centers)

C. Shouldice Repair

• Superior results to Bassini (recurrence <2% at expert centers, but ~10% in general practice)
• Open and double-breast the transversalis fascia (two layers)
• Repair external oblique in two layers
• Technically demanding - preferred at specialized hernia centers

D. McVay (Cooper's Ligament) Repair

• Suture transversalis fascia/conjoint tendon to Cooper's ligament (pectineal ligament)
• Useful for femoral hernias (unlike Bassini)
• A relaxing incision in the anterior rectus sheath is needed to relieve tension

E. Lichtenstein Tension-Free Hernioplasty (Current Gold Standard Open)

1. Incise skin from pubic tubercle to just lateral to deep ring
2. Open external oblique aponeurosis; identify ilioinguinal nerve
3. Mobilize spermatic cord
4. Deal with hernia sac (excise/reduce indirect; invert direct)
5. Place flat mesh (keyhole for spermatic cord):
   • Medial: overlap pubic tubercle by 1.5-2 cm, fix to anterior rectus sheath
   • Inferior: fix to shelving edge of inguinal ligament
   • Superior: fix to internal oblique
   • Lateral tails: wrap snugly around cord at deep ring (not tight)
6. Close external oblique aponeurosis over mesh

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LAPAROSCOPIC REPAIRS

F. TAPP (Transabdominal Preperitoneal)

1. Pneumoperitoneum, 3 ports (umbilical 10 mm + 2×5 mm lateral)
2. Patient in Trendelenburg
3. Incise peritoneum above the hernia defects (medial umbilical ligament to ASIS)
4. Develop preperitoneal space - expose Cooper's ligament, pubic symphysis, deep ring
5. Reduce hernia sac from cord (parietalize cord)
6. Achieve Critical View of MPO (direct, indirect, femoral spaces all visualized)
7. Place mesh ≥15×10 cm covering entire MPO
8. Close peritoneum over mesh with tacks or suture

G. TEP (Totally Extraperitoneal)

1. Small infraumbilical incision to preperitoneal space (anterior rectus sheath opened, retracted)
2. Balloon dissector (or digital/blunt dissection) creates working space in preperitoneal plane
3. CO₂ insufflation of preperitoneal space (not peritoneal cavity)
4. Identical dissection and mesh placement as TAPP
5. Peritoneal cavity is never entered

Mesh Placement in Laparoscopic Repair

• Medial: pubic symphysis (contralateral Cooper's ligament for large direct hernias)
• Superior: 3-4 cm above deep ring
• Inferior: 1-2 cm below pubis into Space of Retzius
• Lateral: against psoas muscle
• Minimum size: 15 × 10 cm (14 × 11 cm also acceptable)
• Never split the mesh around the cord

Fixation in Laparoscopic Repair

• Mesh fixation is not mandatory in the preperitoneal space for small to moderate hernias
• When used, fixation should be confined to safe zones (above iliopubic tract medially; avoid triangles of doom and pain)
• Absorbable tacks preferred over permanent to reduce chronic pain risk

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PART 12: POSTOPERATIVE COMPLICATIONS

Early Complications

Late Complications

1. Recurrence

• Open mesh (Lichtenstein): ~1-5% at 5 years in experienced hands
• Laparoscopic (TEP/TAPP): ~1-4% at 5 years
• Causes: missed hernia defect (especially femoral), inadequate mesh overlap, mesh migration, technical error

2. Chronic Postoperative Inguinal Pain (CPIP)

• Defined as pain persisting >3-6 months after surgery
• Incidence: up to 15% have some CPIP; ~10% have moderate-severe pain
• Only 1-3% seek medical attention for it
• Two types:
  • Neuropathic: Direct nerve injury (cut, crushed, stretched, caught in suture/tack), neuroma formation, mesh pressing on nerve
  • Mechanical (somatic): Mesh mass effect (especially plugs), musculoskeletal restriction, tension from tissue repairs
• Management:
  • NSAIDs + reassurance (most resolve spontaneously)
  • Nerve blocks (diagnostic + therapeutic)
  • If severe and immediate (recovery room): re-explore before scarring
  • Triple neurectomy (ilioinguinal, iliohypogastric, genital branch GFN) + neuroma excision + adhesiolysis + foreign body removal if required
  • Best managed at multidisciplinary pain centers

• Preoperative pain at surgical site
• Open > laparoscopic repair
• Female sex
• Younger age
• High acute postoperative pain
• Psychological factors

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PART 13: SPECIAL SITUATIONS

Bilateral Inguinal Hernia

• Lifetime risk of contralateral hernia after unilateral repair is ~50%
• Laparoscopic repair is preferred for simultaneous bilateral repair (single anesthetic, both sides through same ports)
• Open bilateral repair requires two separate groin incisions

Inguinal Hernia in Women

• Much less common (M:F = 10:1), but femoral hernias are proportionally more common in women
• Always check for a femoral hernia component in women
• Laparoscopic view best distinguishes inguinal from femoral hernias
• Round ligament is in the sac (not cord structures); can be divided at operation
• Ovary or fallopian tube can be the hernia contents

Hernia in Pregnancy

• Open tension-free repair under local anesthesia can be safely performed
• Timing: ideally second trimester if repair is needed electively
• Laparoscopic repair is generally avoided in pregnancy

Recurrent Inguinal Hernia

• After previous anterior open repair: use laparoscopic (TEP or TAPP) - Grade A
• After previous laparoscopic repair: use open anterior (Lichtenstein)
• The principle: always approach from the virgin tissue plane

Hernia with Contamination (Emergency with Strangulation)

• Bowel resection is not an absolute contraindication to mesh
• Synthetic mesh acceptable in clean-contaminated fields (no gross spillage)
• Use primary tissue repair (McVay or Bassini) in grossly contaminated/dirty fields
• Biologic meshes (acellular dermal matrix) can be used when primary repair is not feasible in contaminated fields

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PART 14: SUMMARY TABLE - DIRECT vs. INDIRECT vs. FEMORAL

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