Indirect Inguinal Hernia
An indirect inguinal hernia is considered mainly to be a
congenital lesion. It is denoted “indirect” because the bowel and peritoneum do
not herniate directly through a weakness in the abdominal wall. Rather, the
bowel and peritoneum move through a patent processus vaginalis (hence it being a
congenital defect) and into the scrotum. This also lends to the analogy that
“in”-direct hernias extend “in” through the internal ring. As such, they
technically protrude lateral to the inferior epigastric vessels.
The hernia itself consists of a sac of peritoneum extending
through the internal ring, antero-medial to the spermatic cord in males (or
round ligament in females), through which omentum or bowel can traverse.
The larger the defect and extension into the scrotum, the
higher the risk of incarceration and/or strangulation.
Probably the largest single risk factor for developing an inguinal hernia is
being male. Men are almost 10 times more likely to develop an inguinal
hernia than females. Other factors (which mainly lead to an increased
pressure in the lower abdomen) put the general population at risk. They
Indirect inguinal hernias typically cause a bulge in the groin (at the top of
or within the scrotum) and usually with increased abdominal pressure. The
bulge may or may not be painful. By
palpating the inguinal canal and asking the patient to cough while standing, one can usually
elicit the hernia. In fact, one can often times palpate an inguinal hernia
without invaginating the scrotum (as is typically taught in medical school).
Rather, by placing one's fingers over the inguinal canal and asking the patient
to cough, one can often feel the bulge against the lower abdominal wall.
As indirect and direct hernias are unreliably differentiated by physical exam
alone, the need to invaginate the scrotum to feel into the inguinal canal is
often more uncomfortable to the patient, than revealing to the physician.
Rarely, palpation is not even necessary, as the hernia is large enough to be
Indirect inguinal hernias are the most common type of hernia encountered.
Virtually any patient under the age of 25 presenting with hernia will have an
indirect hernia. They are more prevalent in men (the male to female ratio
being about 9:1). This is because, during their descent, the testicles and
blood vessels pass through the inguinal canal, making the opening from the
abdomen less likely to close completely.
Because indirect hernias originate through the deep inguinal ring, there is
an increased risk that bowel can slip into the canal, become swollen and
engorged, and become trapped outside the abdomen. This is known as
incarceration, and is the second leading cause of bowel obstruction (second only
to adhesions from previous surgery). Bowel can remain incarcerated for
long periods of time without leading to strangulation, however, if the
entrapment of bowel becomes so severe as to compromise blood flow, strangulation
ensues with the risk of bowel necrosis. Strangulation, therefore, is a