Hernias of the Anterolateral Abdominal Wall

Anatomy

  • Layers of the Abdominal Wall:
    • Skin: Epidermis, Dermis
    • Subcutaneous Fat (Superficial Fascia): Fatty (Camper) layer, Membranous (Scarpa) layer
    • Deep Fascia: Investing fascia, Lining fascia (transversalis fascia, psoas fascia, diaphragmatic fascia)
    • Muscle groups: Trunk wall muscles
    • Preperitoneal fat
    • Peritoneum: Parietal, Visceral, Mesentery
    • Fusion plane
  • Trunk Wall Organization:
    • Skin, Subcutaneous fat, Fatty Camper fascia, Membranous Scarpa fascia
    • Investing deep fascia (external oblique fascia)
    • External abdominal oblique muscle
    • Internal abdominal oblique muscle
    • Transversus abdominis muscle
    • Lining deep fascia (transversalis fascia, iliacus fascia, psoas fascia, etc.)
    • Preperitoneal fat, Parietal peritoneum
  • Abdominal Wall Key Points:
    • Central: Linea alba (fusion of rectus fascial layers).
    • Anterior and posterior rectus sheath encircle rectus muscles superiorly.
    • Posterior rectus sheath terminates at arcuate line.
    • Below arcuate line: rectus muscle and anterior rectus sheath only.
    • Lateral: External oblique, internal oblique, transversus abdominis, transversalis fascia.
  • Blood Supply:
    • Central: Superior and inferior epigastric vessels.
    • Lateral: Segmental branches.

Abdominal Hernia

  • Definition: Protrusion of an organ through its containing wall due to weakness.
  • Causes:
    • Congenital anatomical defect.
    • Penetration of abdominal wall by structures.
    • Acquired weakness (trauma, surgery, disease).
    • Increased intra-abdominal pressure.
  • Basic Features:
    • Occur at weak spots.
    • Reduce on lying down or with manipulation.
    • Expansile cough impulse.
  • Common Sites:
    • Inguinal, Umbilical/paraumbilical, Incisional, Femoral, Epigastric.
  • Clinical Presentation:
    • Asymptomatic (reducible).
    • Symptomatic (pain, cramping).
    • Incarcerated (non-reducible).
    • Strangulated (ischemic, urgent repair).
  • Incarceration: Trapping of contents, not always emergent.
  • Strangulation: Ischemia, requires urgent attention.
  • Strangulation Indicators: Nausea/vomiting, severe pain, tachycardia, fever, peritonitis, leukocytosis, acidosis.
  • Hernia factors : Defect characterization via CT scan useful for operative planning
  • Patient Factors:
    • Modifiable Risk Factors: functional status, smoking, obesity, and medical comorbidities may increase perioperative morbidity.
    • Nutritional optimization, weight management, and smoking cessation aid wound healing.

Inguinal Hernia

  • Anatomy of Inguinal Region:
    • External oblique muscle and aponeurosis.
    • Internal oblique muscle.
    • Transversalis fascia.
  • Indirect Inguinal Hernia:
    • Sac begins at the internal ring, inside the spermatic cord.
    • Can descend into the scrotum.
    • Reduces upwards, then laterally and backwards.
    • Controlled by pressure over the internal inguinal ring.
    • Bulge reappears in the middle of the inguinal region and flows medially and obliquely towards the scrotum
    • All age groups including children
  • Direct Inguinal Hernia:
    • Sac appears medial to the inferior epigastric artery, outside the spermatic cord.
    • Does not go down into the scrotum.
    • Reduces upwards and then straight backwards
    • Not controlled after reduction by pressure over internal inguinal ring.
    • Bulge reappears directly forwards
    • Rare in children and young adults
  • Inguinal Ligament: Runs between anterior superior iliac spine and pubic tubercle.
  • Internal Spermatic Fascia: Derived from transversalis fascia.
  • Cremaster Muscle and Fascia: From internal oblique muscle.
  • External Spermatic Fascia: From external oblique aponeurosis.
  • Weak spot: Half-moon shape gap beneath the arch of the internal oblique muscle.

Technique for Examination

  • Standing Examination: Start examination standing
  • Palpation: Flat on groin, parallel to inguinal ligament, other hand on patient's back
  • Lump Assessment:
    • Site and shape.
    • Scrotal extension.
    • Other swellings.
  • Scrotal Examination: Differentiate hernia from scrotal lump.
    • If lump passes into canal, it is a hernia
  • Lump Features:
    • Position, Temperature, Tenderness, Shape, Size, Tension, Composition, Reducibility.
  • Cough Impulse: Confirm by asking patient to cough and movement in one direction isn't enough
  • Reducibility Evaluation
    • Compress to soften, lift towards external ring.
    • Check if controlled (kept inside) by pressure at internal ring (indirect hernia).
  • Reappearance Observation:
    • Indirect hernia slides obliquely downwards, direct projects directly forwards.
  • Other Side: Check other inguinal region, bilateral hernias are quite common
  • Abdominal Exam: Check for factors raising intra-abdominal pressure.
  • Flat-Lying Cough: Helps determine if direct or indirect.

Inguinal Hernia. Elective/Emergency presentation

  • History:
    • Age.
    • Occupation.
    • Local symptoms, abdominal symptoms
    • Enlargement, pain.
  • Emergency:
    • Groin swelling will not reduce
    • Painful and tender
    • Cardinal symptoms of intestinal obstruction - colicky abdominal pain, vomiting, distension and absolute constiptation
  • Strangulated Hernia:
    • Tight ring constricts blood supply.
    • May cause intestinal obstruction.
    • Small sac may result to Richter's hernia
  • Complications:
    • Irreducible: contents cannot be replaced.
    • Incarcerated: contents imprisoned but alive.
    • Obstructed: lumen obstructed but bowel alive.
    • Strangulation: blood supply compromised.
  • Emergency - Check for - :Skin color, Temperature, Tenderness, Reducibility.
  • Appendicectomy: may increase incidence of direct right inguinal hernia.
  • Pantaloon Hernia: Both a direct and an indirect hernia in the same groin
  • Sliding Hernia: Partly extraperitoneal bowel within the sac.
  • Maydl's Hernia: Strangulation of a loop of bowel between two other bowel loops
  • Recurrent hernias - are more likely to present with local pain, tend to be direct etc

Inguinal Hernia in Females

  • Hernias follow the round ligament and are indirect.
  • Conditions Unique to Females:
    • Hydrocele of the canal of Nuck (fluid-filled distal sac of indirect hernia).
    • Haematocele of the round ligament (round ligament distended with blood, resolves post-pregnancy).

Femoral Hernia

  • Anatomy: Protrusion through the femoral canal is rare in children and common above 50 years old.
    • Boundaries: inguinal ligament (anteriorly), pubic ramus and pectineus muscle (posteriorly), lacunar ligament and pubic bone (medially), femoral vein (laterally).
  • Contents: loose areolar tissue and a lymph gland known as the gland of Cloquet
  • Symptoms: usually, the patient discovers the swelling. Femoral hernias are common in elderly due to obstruction or strangulation. Partial strangulation of the bowel wall (Richter’s hernia) is likely, because of the narrow neck
  • The sac remains palpable even when empty, so seems to be irreducible. May be bilateral.
  • Position: Neck below the inguinal ligament and lateral to pubic tubercle.
  • Femoral hernias are not usually tender unless strangulated.

Umbilical Hernia

  • True Umbilical Hernia: Through umbilical scar, tethered skin. In adults can be of raised intra-abdominal pressure
  • Paraumbilical Hernia: Adjacent to the umbilical scar, not into the center.
    • Develop in middle and old age.
    • More common in females than in males, and are associated with parity and obesity
    • Swelling and discomfort are symptoms.
  • Strangulation regularly occurs. extraperitoneal fat or omentum is common.

Epigastric Hernia

  • Protrusion of extraperitoneal fat between xiphisternum and umbilicus.
  • the patient complains of epigastric pain, which is localized exactly to the site of the hernia but often does not notice the underlying lump
  • Pain associated with eating is common.
  • Feel firm, no cough impulse, irreducible.

Rare abdominal hernias

  • Spigelian Occur at edge of the rectus sheath, below the umbilicus and above the inguinal area. Diagnosing is difficult in obese patients
  • Obturator come through obturator foramen resulting to small bowel obstruction. Compresses the obturator nerve which causes pain in the medial part of the thigh.
  • Lumbar and gluteal hernia associated with previous surgery. Diagnosis require imaging by magnetic resonance imaging

Surgical Approaches

  • Primary Repair: suture along is performed with small defects
  • Mesh Repair: placement of mesh is preferrable to reduce tissue tension reduce recurrence risk
  • Open Approach: shorter operative time, not demand general anesthesia, also may or may not require distant adhesiolysis

Umbilicus Abnormalities

  • Congenital: exomphalos, persistent fistulas.
  • Acquired: inflammation, tumor invasion.
  • Omphalitis: infection, foul smell.
    • The skin within and around the umbilicus is red and tender, and exuding a seropurulent discharge with a characteristic foul smell
  • Discharge Causes:
    • Congenital: Vitellointestinal remnant, patent urachus.
    • Acquired: Granuloma, Dermatitis (intertrigo), Ompholith, Fistula, Secondary carcinoma, Endometriosis.
  • Ompholith: Accumulation of sebaceous secretions, hair, and fluff. Patient will have a throbbing, painful and swollen umbilicus
  • Secondary Carcinoma (Sister Joseph’s Nodule): metastatic cancer presentation. The tumor cells reach the umbilicus via lymphatics that run in the edge of the falciform ligament alongside the obliterated umbilical vein, or by transperitoneal spread
  • Endometrioma: Ectopic endometrial tissue in the umbilicus.
  • Discoloration:
    • Caput medusa: portal hypertension and liver failure.
    • Yellow-blue bruising Cullen's sign/Grey Turner's sign: severe acute pancreatitis.
    • Bruising at the umbilicus: intra-abdominal bleeding