Hernia indd

Interparietal hernia
Interparietal hernias refer to hernias located in the fascial planes of 
the anterior abdominal wall muscles that do not exit into the subcu-
taneous tissue. These most commonly occur in the inguinal region. 
Similar to the Richter and Littre hernias, these have a high rate of 
incarceration and strangulation
(4)
.
Amyand Hernia
Named after the surgeon who performed the first appendicectomy, 
this rare form of inguinal hernia (<1% of inguinal hernia) is when 
the appendix is included in the hernial sac and becomes incarcer-
ated. The resultant appendicitis in incarcerated hernia is commonly 
misdiagnosed as an ordinary incarcerated hernia. Symptoms mim-
icking appendicitis may occur. Treatment consists of a combination 
of appendectomy and hernia repair. Diagnosis is rarely made pre-
operatively and the medical history and the physical examination 
usually point to incarcerated hernia with localized peritonitis.
Littre’s hernia
Littre hernia refers to a hernial sac containing a Meckel’s diverticu-
lum. As a Meckel’s diverticulum is a common congenital abnor-
mality, it is not surprising that they become involved in hernias. 
Although Littre’s original report related to femoral hernias, the 
Meckel’s diverticulum can be involved in inguinal hernias (50%), 
femoral (20%), umbilical (20%) and others (10%) 
(13)
. The diagnosis 
of a strangulated Littre’s hernia is unlikely to be made preoperatively 
as the presenting signs and symptoms are more subtle and evolve 
more slowly than those of strangulated small intestine
(11)
.
Summary
Abdominal wall hernias are diagnosed by careful history and physi-
cal examination combined with clinical acumen. Medical imaging 
is usually reserved for hernia complications. Plain abdominal x-rays, 
US, CT, MRI and Herniography are all useful investigations in the 
appropriate setting. Knowledge of the relevant anatomy is important 
in differentiating the type of hernia and in identifying those hernias 
that are at risk of complications. The radiologist must be familiar 
with the imaging finding in the unusual hernias.