Hernias-Summer_2024

Hernias VMS 5649 Small Animal Surgery

Definition

  • Protrusion of a tissue or organ through a defect in the wall of the anatomical cavity in which it normally lies.

Terminology

  • True Hernia: Anatomical hernial sac.

  • False Hernia: Lacks hernial sac.

  • Traumatic Hernias: Initially false hernias, which will develop hernial sac with chronicity.

  • Hernial Structures:

    • Neck

    • Ring

    • Hernial sac

    • Body wall

Classification

  • Types:

    • Ventral: Involving the front of the abdomen.

    • Congenital VS. Acquired: Present at birth vs. developed over time.

  • Anatomical Sites:

    • Umbilical

    • Paracostal

    • Cranial pubic ligament

    • Irreducible or ligament

    • Incarcerated

    • Complicated: Strangulation and Obstruction.

Incarceration

  • Definition: Contents become irreducible.

  • Risk: May lead to strangulation.

Strangulation

  • Definition: Blood supply compromised, leading to ischemia and potential necrosis.

Loss of Domain

  • Chronic Hernias: Particularly diaphragmatic.

  • Definition: Normal location too small to accommodate reduced contents, leading to compartment syndrome.

Anatomic Location

  • Internal Hernias: Occur through a ring of tissue within abdominal wall or thorax, e.g., diaphragmatic, hiatal, mesenteric, intercostal.

  • External Hernias: Defects in external wall of abdomen, e.g., ventral, cranial pubic ligament.

Additional Hernia Sites

  • Umbilical Hernia

  • Inguinal Hernia

  • Femoral Hernia

  • Scrotal Hernia

Pathogenesis

  • Types:

    • Congenital: Genetic and heritable factors.

    • Acquired: Traumatic, non-traumatic, and iatrogenic.

Diagnosis

  • Steps include:

    • Thorough history taking.

    • Physical examination.

    • Radiographic examination.

    • Ultrasound.

    • Advanced imaging techniques.

Principles of Herniorrhaphy

  1. Return contents to normal location.

  2. Secure ring closure.

  3. Tension-free closure.

  4. Utilize patient tissues.

Surgical Materials

  • Considerations:

    • Suture material (e.g., Monosof, PDS).

    • Type of hernia.

    • Condition of patient.

    • Risk factors for recurrent hernia.

Types of Herniorrhaphy

  • Open: Hernial sac incised and removed (freshening edges avoided).

  • Closed: Invert sac and contents without opening the hernial sac.

Umbilical Hernia

  • Cause: Failure of fusion of rectus abdominis muscle at umbilicus; may close spontaneously up to ≈ 6 months.

  • Breed Predispositions: Airedales, Pekingese, Basenji, Pointers, Weimaraner.

  • Clinical Signs: Soft round mass at umbilical scar, often reducible; may have gastrointestinal signs if obstructed.

  • Treatment:

    • Small (<3mm) or large (>2.5cm): use clinical judgment.

    • Patients < 6 months may close spontaneously.

    • Repair recommended during elective procedures.

Inguinal Hernia

  • Types:

    • Congenital or acquired.

    • Common in young ( < 2 years) and middle-aged intact female dogs and male dogs.

  • Breed Predispositions: Basenji, Basset hound, etc. Heritability noted in Cocker Spaniel and Dachshund.

  • Surgical Approach:

    • Female: Ventral midline can correct both sides.

    • Males: Inguinal approach.

Scrotal Hernia

  • Characteristics: Common in young dogs < 2 years; associated with cryptorchidism; usually unilateral.

  • Treatment: Incision over ring, reduce contents, close ring, and may castrate to facilitate repair.

Traumatic Abdominal Hernias

  • Cause: Associated with blunt trauma (HBC).

  • Clinical Signs: Bulging mass, asymmetric abdomen, reducibility.

  • Treatment: Stabilize patient first; emergency surgery might be necessary based on severity.

Acute vs. Chronic Abdominal Hernia Repair

  • Acute: Can explore abdomen and repair organ injuries; difficulty in reconstruction; tension-relieving patterns used.

  • Chronic: Less likely concurrent injuries; better anatomic closure achievable.

Cranial Pubic Ligament/Prepubic Tendon Avulsions

  • Surgical Considerations: Often associated with pelvic fractures; patient positioning is crucial during surgery.

Incisional Hernias

  • Types: Acute vs. chronic, with chronic being those that occur weeks, months, or years later.

  • Risk Factors: Poor surgical technique; altered tissue strength.

  • Diagnosis: Exaggerated swelling, serosanguinous discharge, radiographic signs.

  • Treatment: Determine and address underlying factors; anatomical closure recommended.