Page 20 - herina surgery and possible lawsuits

transverses abdominis muscle also tenses the crura of the internal ring, derived from
its transversalis fascia. At the same time, the anterior wall of the canal, made up of
external oblique aponeurosis, presses on the internal inguinal ring and the floor of the

inguinal canal, counter balancing intra abdominal forces pushing outward. The
inguinal ligament is pulled upward by the same contraction, moving cranial to narrow
the inguinal canal. As muscular power diminishes with age or disease, i.e.,

neuropathy, wasting, etc., these protective mechanisms fail, leaving the transversalis
fascia at risk. [48]
Increased intra abdominal pressure as a cause of groin hernia has been promulgated since

the time of Cooper. He stated that the cause of hernia was mechanical disparity
between visceral pressure and resistances of abdominal musculature. If the first
increased over the second, the abdominal wall ruptured, and a hernia emerged. There

are factors that increase intra abdominal pressure includes cough, obesity,
constipation, pregnancy, ascites, and unusual exertion (e.g., heavy lifting), prostatism
etc. which leads a repeated mechanical stress and injury on the abdominal wall. If

healing takes place, it will be less strong and less resilient than the original tissue. If
there is actively raised intra abdominal pressure the counter mechanism activated and
hernia does not appear, but when it raise passively the abdominal muscles are relaxed
and counter mechanism do not activated leading to hernia. Excess body weight is no

longer considered to be a factor in the development of groin hernias. In fact, adiposity
may even have a protective influence against the development of a groin henna. [47,
48]

2. Metabolic Factors play important role in integnty of fascia transversalis. Transversalis
fascia is supported by muscle or aponeurosis fibres. These fibres are metabolically
active and constantly balance state of production and absorption of collagen. So the

factors affect these balance may have role in development of hernia.
Increased proteolytic activity may cause weakness in structural tissue. Matrix metallo-
protease (MMP)-2 over expression was measured in fibroblasts of patients with direct

inguinal hernias, and MMP-13 over expression was detected in patients with recurrent
inguinal hernias. Studies like these are observational, and it is not clear whether
increased MMP expression leads to direct inguinal hernia formation. Alternatively,
falling groin tissue may secondarily express increased MMP levels. Over expression

of enzymes has been noted m aneurysms as well. [49]

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