Umbilical Hernia

Notes

Overview

Umbilical hernias are one of the most common surgical conditions in infants and children. In infantile umbilical hernia there is a pathological failure of obliteration of umbilical defect. Umbilical hernia can also occur in adults and is usually acquired due to increased intrabdominal pressure due to obesity, pregnancy, ascites. Management is surgery.

Definition

Hernia: A bulge or protrusion of an organ or tissue through an abnormal opening within the anatomic structure that normally confines it.
Umbilical hernia: Protrusion through umbilical ring, causing eversion of the umbilicus. Its attenuated fibres are at the apex of the hernia sac. It is often caused secondary to increases in volume of contents of abdominal cavity (e.g. from obesity, ascites, large benign or malignant intra-abdominal tumours).
Paraumbilical hernia: Paraumbilical hernias are situated just above the umbilicus, and unlike umbilical hernias, have no potential for spontaneous closure
Reducible: Refers to a hernia that can be moved back into place easily (either manually or spontaneously).
Irreducible: Refers to a hernia that CANNOT be moved back into place, remains budged. Irreducible hernia can lead to a incarcerated, obstructed or strangulated hernia.
Incarcerated: Refers to a hernia that cannot be pushed back. It does not necessarily mean that the hernia is strangulated or that obstruction is occurring (although both are possible). If spontaneously reduced, and patient feels better.
Obstructed hernia: gut hernia causing incarceration (momentum hernia does not cause incarceration because gut flow is normal).
Strangulated hernia: compression of blood flow to the strangulated bowel leading to necrosis.

Side note

The composition of a hernia is 1. the sac, 2. the covering of the sac 3. the content of the sac.

Anatomy and Physiology

Umbilical Cord traverses the abdominal wall through the umbilical ring to supply the featus with nutrients.

Umbilical vein
Paired umbilical arteries
Vitelline duct and allantois compose the umbilical cord.

Umbilical ring is a defect in the dense fascia of the linea alba.

After birth, the umbilical cord is cut leaving a stump (umbilical cord stump) that is still transversing the umbilical ring.
The umbilical ring normally closes by contracture after the cord is ligated and the umbilical vessels thrombosed. This is essentially healing of the umbilical ring defect.
The umbilical vein obliterates and becomes a fibrous cord (round ligament of the liver) which attaches to inferior margin of umbilical ring to provide strength and protection from umbilical hernia.

Side note

In 25% of infants, the round ligament attaches to superior border of umbilical ring, leaving a weakened umbilical floor composed of only peritoneum and umbilical fascia.

Aetiology and Risk Factors

Aetiology

During featal development and at birth the umbilicus is where the Umbilical cord supplies the featus/baby with nutrition, etc from the placenta.
At birth the umbilical defect is present at birth.
The umbilical cord is cut leaving a stump.
The stump of the umbilical cord heals, usually within a week of birth closing the umbilical defect.

Neonatal/infant umbilical hernia

The healing and closure of the umbilical defect is delayed, leading to the development of herniation.

Adult umbilical hernia

Reopening of the umbilical defect later in life, caused by conditions that cause thinning and stretching of the midline raphe (linea alba). Basically increased intraabdominal pressure due to:
- Obesity
- Repeated pregnancies
- Obesity
- Ascites

Risk Factors

Infants

Low birth weight (<1500g)
African-American ethnicity
Beckwith-Wiedemann syndrome (BWS)
Trisomy 21, 18
Congential Hypothyroidism

Adults – Causes of increased intra-abdominal pressure

Obesity
Pregnancy
Ascites (disease)

Clinical Manifestation

Swelling/lump in the umbilical region +/- reducible
Pain
Cough impulse
Dermatitis

Classification

UMBILICAL HERNIA
	Congenital	Acquired direct	Acquired indirect
Age
Aetiology	Umbilical hernia in neonates following ligation of the umbilical cord due to failure of umbilical ring to close