Hernia indd

Paraumbilical Hernias
Para-umbilical hernias occur through the linea alba in the region of 
the umbilicus and usually relate to diastasis of the rectus abdomi-
nis muscles 
(6)
. Para-umbilical hernias do not reduce spontaneously 
and have a high prevalence of incarceration (irreducible sac) and 
strangulation (ischaemia caused by compromised blood supply) sec-
ondary to their small hiatal necks. They are far more common than 
acquired umbilical hernias within the adult population as the defect 
is not through the original umbilical scar but rather via an acquired 
defect in the linea alba. Acquired umbilical hernias behave like 
para-umbilical hernia in that they have tendency to incarcerate and 
strangulate. Incarceration is up to 14 times more common in adults 
than children 
(7)
.

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In terms of aetiology, 20% of lumbar hernias are congenital and 25% 
are traumatic 
(16)
. Most of the primary lumbar triangle hernias occur 
through the inferior lumbar triangle. The neck of an inferior lumbar 
hernia is usually large hence strangulation is uncommon. Inferior 
lumbar hernias occur more often in males and on the left side. 
Traumatic lumbar hernias following surgery (e.g. kidney procedure, 
bone graft harvest from iliac crest, latissimus dorsi flap), blunt in-
jury or penetrating injury may be large and may not conform to the 
anatomical boundaries of the lumbar region 
(4,5)
. They may contain 
retroperitoneal fat, kidney, colon or intraperitoneal structures (most 
commonly small intestine). Incarceration and strangulation may oc-
cur. 
Patients usually present with a protruding bulge in lumbar region. 
These hernias are difficult to diagnose in obese patients. CT allows 
differentiation from haematoma, renal mass, abscess and other soft 
tissue tumours.