55. Umbilical hernia, umbilical cysts and fistulas

1. Definition

• Umbilical hernia → hernia through the umbilical ring
  • Infantile (congenital) → through the unclosed umbilical ring after birth
  • Paraumbilical (adult) → through the linea alba just above or below the umbilicus
• Umbilical cyst, sinus or fistula → remains of the vitelline (omphalomesenteric) duct or urachus that did not close

2. Epidemiology

• Infantile umbilical hernia → about 10–20% of newborns; more in African-Caribbean, premature and low-birth-weight babies
• Most close by 2–3 years (over 80%)
• Paraumbilical hernia → adults over 35; women 3–5 times more than men; obese, multiparous
• Umbilical and paraumbilical → about 10% of primary abdominal wall hernias in adults
• Meckel's diverticulum → 2% of people ("rule of 2s")
• Urachal remnants → rare; more in boys

3. Aetiology and risk factors

Embryology (revision)

• Umbilical cord carries:
  • Two umbilical arteries → become the medial umbilical ligaments
  • One umbilical vein → becomes the ligamentum teres (in the falciform ligament)
  • Vitelline duct → joins the midgut to the yolk sac; normally closes by week 7–9
  • Allantois → urachus → joins the bladder to the umbilicus; becomes the median umbilical ligament
• After birth → the ring closes by scarring

Umbilical hernia

• Infant → umbilical ring not fully closed; prematurity, Down's syndrome, hypothyroidism, Beckwith-Wiedemann, mucopolysaccharidoses
• Adult → raised pressure on a weak linea alba:
  • Obesity, multiple pregnancies
  • Ascites (cirrhosis), peritoneal dialysis
  • Chronic cough, straining
  • Divarication of the recti
  • Laparoscopic port at the umbilicus

Cysts and fistulas

• Vitelline duct → whole duct open, part open, or fibrous band
• Urachus → whole or part open; bladder outlet obstruction keeps it open

4. Pathogenesis

• Infantile → true umbilical defect; wide neck, symmetric; strangulation very rare
• Paraumbilical → defect in the linea alba next to the umbilicus; narrow neck with fibrous edge; sac contains omentum or bowel; higher risk of incarceration and strangulation
• Ascites → hernia stretches thin; skin may ulcerate and rupture → ascitic leak, peritonitis (Flood syndrome)
• Infected remnants → abscess, discharge at the umbilicus

5. Classification

Umbilical hernia

• Infantile (true umbilical)
• Paraumbilical (supra- or infraumbilical)
• Adult true umbilical
• Exomphalos → congenital defect with a sac (see abdominal wall defects)
• EHS ventral hernia → M3 (umbilical); width W1 < 2 cm, W2 2–4 cm, W3 > 4 cm

Vitelline duct remnants

1. Patent vitelline duct (umbilical-ileal fistula) → whole duct open; faecal or ileal discharge from the umbilicus
2. Umbilical sinus → outer end open
3. Vitelline (enterocystoma) cyst → middle part open
4. Fibrous band → umbilicus to ileum; volvulus, obstruction
5. Meckel's diverticulum → inner end open (most common)
6. Umbilical polyp (granuloma) → red mucosal tag

Urachal remnants

1. Patent urachus → urine leaks from the umbilicus
2. Urachal cyst → middle part; lower midline mass, infection
3. Urachal sinus → outer end; discharge
4. Urachal (vesicourachal) diverticulum → bladder end; urinary infection, stones
5. Urachal adenocarcinoma → rare; at the bladder dome

6. Clinical picture

Symptoms

• Infant → soft bulge at the umbilicus, larger on crying; painless
• Adult paraumbilical → lump beside the umbilicus, pain, dragging, colic; may become irreducible
• Large hernia → skin changes, intertrigo, ulceration
• Strangulation → painful, tense, red, irreducible lump, vomiting
• Remnants:
  • Discharge from the umbilicus → faeces or bowel content (vitelline) or urine (urachus), mucus, pus
  • Red moist polyp
  • Lower abdominal midline mass, fever, dysuria (infected urachal cyst)
  • Bowel obstruction (band, volvulus)

Signs

• Infant → central, symmetric bulge; defect felt with a fingertip; reduces easily
• Paraumbilical → crescent-shaped umbilicus (sac displaces the umbilicus to one side); firm neck; cough impulse
• Ascites → tense, thin-skinned, shiny hernia
• Granuloma → small pink tissue after the cord separates (no mucosa)
• Polyp → mucosa (bowel); does not respond to silver nitrate

7. Diagnosis

• Hernia → clinical
• Ultrasound → small or obese patients, contents
• CT → obese patients, multiple defects, complications, divarication
• Remnants:
  • Ultrasound of the umbilicus and bladder → cysts, urachal tract
  • Fistulogram (sinogram) → contrast fills ileum (vitelline) or bladder (urachus)
  • Micturating cystourethrogram → patent urachus; exclude bladder outlet obstruction
  • Discharge analysis → creatinine (urine), bile, bowel content
  • Meckel's scan (technetium pertechnetate) → bleeding Meckel's
  • Biopsy of a polyp → gastric or intestinal mucosa

8. Differential diagnosis

• Umbilical granuloma versus polyp
• Paraumbilical hernia versus lipoma, divarication of the recti (no defect)
• Sister Mary Joseph nodule → umbilical metastasis (stomach, colon, ovary, pancreas)
• Umbilical endometriosis (cyclical bleeding)
• Omphalitis (infection of the cord stump in newborns)
• Caput medusae → portal hypertension
• Pilonidal sinus of the umbilicus
• Cullen's sign → periumbilical bruising (pancreatitis, ruptured ectopic)

9. Treatment

Conservative

• Infantile umbilical hernia → wait; most close by 2–3 years
  • No strapping or coins (no benefit, skin damage)
  • Repair if → persists after 3–4 years, defect > 1.5–2 cm, growing, incarcerated, or symptomatic
• Umbilical granuloma → silver nitrate cautery, or salt application, or ligation
• Ascites → control the ascites first (diuretics, paracentesis, TIPS); repair after

Surgical: umbilical hernia

• Infant:
  1. Curved infraumbilical skin-crease incision
  2. Dissect and reduce the sac
  3. Close the fascia with absorbable sutures
  4. Fix the umbilical skin down to the repair (keeps the navel shape)
• Adult paraumbilical → repair almost always (risk of strangulation):
  • Defect < 1 cm → sutured repair with non-absorbable sutures
  • Defect ≥ 1 cm → mesh (preperitoneal flat mesh or patch) → lower recurrence than suture (EHS guidelines)
  • Large defects, obese, recurrent, multiple defects → laparoscopic IPOM or open retromuscular (Rives-Stoppa) mesh
  • Mayo "vest-over-pants" repair → historical; no better than simple closure
  • Very large hernia with skin damage → excise the umbilicus (omphalectomy)
• Strangulated → emergency repair; open the sac, resect dead omentum or bowel; sutured or biological mesh if contaminated
• Cirrhosis with ascites → emergency repair for rupture or strangulation; elective repair after ascites is controlled

Surgical: remnants

• Vitelline remnants → excise the whole tract with a wedge of ileum, or short ileal resection with anastomosis, via an umbilical or small laparotomy incision
• Umbilical polyp → excise; explore for a deeper remnant
• Urachal remnants → complete excision of the tract down to the bladder dome, with a cuff of bladder (prevents recurrence and cancer)
  • Infected urachal cyst → drain first, antibiotics, then excise later
  • Correct any bladder outlet obstruction

10. Complications

• Hernia → incarceration, strangulation, skin ulceration, rupture (ascites)
• Repair → seroma, wound infection, recurrence (higher with suture repair, obesity, smoking), mesh infection, umbilical skin necrosis
• Vitelline → bleeding (ectopic gastric mucosa), obstruction, volvulus, intussusception, Meckel's diverticulitis
• Urachal → infection, abscess, stones, urachal carcinoma