10.1 Inguinal, Femoral & Ventral Hernias

Inguinal, Femoral & Ventral Hernias

Abdominal wall hernias represent one of the most frequent surgical conditions encountered in general practice and clinical exams like the UPSC Combined Medical Services (CMS). A hernia is defined as an abnormal protrusion of a membrane-guided visceral content through a weakness or defect in the wall of its containing cavity.

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1. Anatomy of the Inguinal Canal

The inguinal canal is an oblique intermuscular passage roughly 4 cm in length directed inferiorly, medially, and anteriorly in the lower anterior abdominal wall. It extends from the deep inguinal ring to the superficial inguinal ring.

Anatomical Boundaries & Landmarks

• Deep Inguinal Ring: A U-shaped defect in the fascia transversalis, located 1.5 cm above the mid-inguinal point (the midpoint between the Anterior Superior Iliac Spine [ASIS] and the Pubic Symphysis). Note: Do not confuse this with the midpoint of the inguinal ligament (between ASIS and Pubic Tubercle).
• Superficial Inguinal Ring: A triangular opening in the external oblique aponeurosis, situated superior and lateral to the pubic tubercle.
• Anterior Wall: External oblique aponeurosis along its entire length, reinforced laterally by the internal oblique muscle.
• Posterior Wall: Fascia transversalis along its entire length, reinforced medially by the conjoint tendon (formed by the fused aponeuroses of internal oblique and transversus abdominis).
• Roof: Arched lower fibers of the internal oblique and transversus abdominis muscles.
• Floor: Inguinal ligament (Poupart's) rolled-in lower edge, reinforced medially by the lacunar ligament (Gimbernat's).
• Contents: Spermatic cord in males (containing 3 arteries: testicular, cremasteric, artery to vas; 3 nerves: ilioinguinal [outside cord], genital branch of genitofemoral, sympathetic fibers; 3 other structures: vas deferens, pampiniform plexus of veins, lymphatics), Round ligament of uterus in females, and the Ilioinguinal nerve (enters canal between internal and external oblique muscles, exits superficial ring).

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2. Direct vs. Indirect Inguinal Hernia

Hesselbach's Triangle Boundaries

• Medial Boundary: Lateral border of the rectus abdominis muscle.
• Lateral Boundary: Inferior epigastric vessels.
• Inferior Boundary: Inguinal ligament (Poupart's).
• Floor: Fascia transversalis (weakened in direct hernia).

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3. Surgical Classification: Nyhus Classification

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4. Femoral Hernia

Femoral hernia accounts for ~5% of all groin hernias but carries the highest incidence of incarceration and strangulation (15-20%). It occurs when abdominal contents pass through the femoral canal into the thigh.

Femoral Canal Boundaries

• Anterior: Inguinal ligament.
• Posterior: Pectineal ligament (Cooper's ligament) covering the pectineus bone.
• Medial: Lacunar ligament (Gimbernat's) - sharp, rigid boundary responsible for strangulation.
• Lateral: Femoral vein (separated by a fibrous septum).
• Clinical Presentation: Swelling situated below and lateral to the pubic tubercle (unlike inguinal hernia which is above and medial). More common in females due to a wider pelvis and broader lacunar ligament.
• Surgical Approaches:
  1. Low Approach (Lockwood): Incision below inguinal ligament; suitable for uncomplicated elective cases.
  2. High Approach (McEvedy): Vertical paramedian or transrectus incision; choice in emergency setting for strangulated femoral hernia with bowel resection.
  3. Transinguinal Approach (Lotheissen): Incision through posterior wall of inguinal canal.

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5. Ventral & Incisional Hernias

• Epigastric Hernia: Protrusion of extraperitoneal fat (and eventually peritoneal sac) through decussating fibers of the linea alba between Xiphoid process and Umbilicus. Presents as a small, tender, non-reducible midline lump.
• Umbilical vs. Paraumbilical Hernia:
  • Umbilical: Congenital defect in infants due to incomplete closure of umbilical ring; >90% resolve spontaneously by age 3-5 years.
  • Paraumbilical: Acquired defect in adults occurring through the supra- or infra-umbilical defect. Associated with multiparity, obesity, and ascites. High risk of strangulation.
• Incisional Hernia: Protrusion through a previous operative scar. Risk factors include wound infection, emergency laparotomy, midline incision, obesity, steroid therapy, and malnutrition. Treatment requires mesh repair (sublay/Rives-Stoppa or IPOM).

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6. Surgical Repair Techniques & Complications

• Lichtenstein Tension-Free Mesh Repair: Gold-standard open repair. A synthetic non-absorbable polypropylene mesh is sutured to the pubic tubercle, lacunar ligament, inguinal ligament inferiorly, and internal oblique aponeurosis superiorly, reinforcing the posterior wall.
• Tissue Repairs (Non-Mesh):
  • Shouldice Repair: 4-layer continuous suture repair of fascia transversalis; lowest recurrence rate among tissue repairs.
  • Bassini Repair: Suturing conjoint tendon to inguinal ligament.
  • McVay Repair: Suturing conjoint tendon to Cooper's ligament (covers both direct and femoral defects).
• Laparoscopic Repairs:
  • TEP (Totally Extraperitoneal): Preperitoneal space entered without violating peritoneal cavity.
  • TAPP (Transabdominal Preperitoneal): Peritoneal cavity entered, mesh placed in preperitoneal space.
• Postoperative Complications:
  • Chronic Groin Pain (Inguinodynia): Pain lasting >3 months post-op due to entrapment or injury of the ilioinguinal, iliohypogastric, or genital branch of genitofemoral nerve.
  • Ischemic Orchitis & Testicular Atrophy: Caused by thrombosis of the pampiniform venous plexus following extensive dissection of a large indirect sac.
  • Recurrence: Main causes are inadequate mesh size (<15x10 cm), failure to overlap pubic tubercle by 2 cm, and infection.