FEMORAL HERNIA
A protrusion of parts of the abdominal viscus or of peritoneal fatty tissue through the femoral ring is termed a femoral hernia. Its incidence is far lower than that of the inguinal hernias. It is very seldom seen in children and is more common in women than in men (ratio 3:1). The right side is affected twice as frequently as is the left. Femoral hernias appear to be an acquired condition resulting from weakening or disruption of the fibromuscular tissue caused by an underlying connective tissue disorder or following injury or from increased intraabdominal pressure. The higher incidence in parous women suggests muscular weakening related to pregnancy or childbirth, but this finding has not been demonstrated in studies.
The
protruding structures, pushing ahead their peritoneal covering and adherent tissue
(mostly fat tissue), descend almost vertically behind and beneath the inguinal ligament
and through the femoral ring. This ring presents the superior margin of the only
potential space in most persons, known as the femoral canal, which is in reality
the most medial portion of the venous compartment of the femoral sheath (i.e., anteriorly,
a downward prolongation of the transversalis fascia over the femoral vessels, and
posteriorly, a continuation of the pectineal fascia derived from the iliac fascia).
Medially, these two fascial layers are adherent to each other, and as they descend,
they blend with the adventitia of the vessels, so that the sheath assumes a funnel-like
configuration around the vessels. Just below the inguinal ligament, the femoral
sheath (and its most medial portion, the femoral canal) lies under cover of the
fascia lata, except in the region of the fossa ovalis, where the cover consists
of the much weaker cribriform fascia. An advancing femoral hernia, after having
entered the femoral ring, opens up the femoral canal, displacing and narrowing
the femoral vein. The hernial sac usually emerges through the fossa ovalis,
pushing the cribriform fascia ahead of it. The sac may then turn upward and may even extend to the region in front of or above the
inguinal ligament by following the superficial epigastric vessels, or the
sac may turn medially toward or into the scrotum or labium majus, respectively.
Laterally, the sac may pass over the femoral vessels or may descend downward
along the saphenous vein. The neck, however, remains always below the inguinal
ligament and lateral to the pubic tubercle, and the fundus of the sac lies usually
in the medial part of the Scarpa triangle (trigonum femorale). A rather surprising
number of varieties, some indeed very rare, have been described. The sac may
rest on the femoral sheath anterior to the femoral vessels (prevascular hernia)
or may descend behind the vessels (retrovascular hernia). The sac may
become divided at the femoral ring, one part following the normal route and another
being directed toward the obturator foramen. A femoral hernia may also become
bilocular by virtue of an aberrant obturator artery. It also has been observed
that a direct inguinal hernia may shift to the femoral region instead of descending
into the scrotum (cruroscrotal hernia), thus simulating a femoral
hernia.
Femoral
hernias can be easily overlooked if small, but when part of the intestine is contained
in the sac, pain is likely to be severe. Complications occurs with great frequency,
with 40% of cases presenting as emergencies as strangulation or incarceration. The
diagnosis can usually be made upon finding a soft bulge at the femoral fossa located
above the inguinal ligament and lateral to the pubic tubercle. Difficulties in the
differential diagnosis may arise if the hernial sac has turned upward over the inguinal
ligament along the superficial epigastric vein. In diagnosing a femoral hernia,
reducible or not, one must exclude also inguinal adenitis, lipoma, varicosities
of the saphenous vein, psoas abscess, obturator hernia, hydrocele of the femoral
sac, hydatid cysts, dermoid cysts, and other
processes, which can produce a local, soft, and fluctuant swelling. The omentum
and small bowel are the most frequently herniated structures, but the presence of
an appendix (usually inflamed), a Meckel diverticulum, or a portion of the bladder
(type of sliding hernia), ureter, or broad ligament has also been observed.
The
treatment of a femoral hernia is surgical. Due to the higher incidence of complications,
surgical repair of a femoral hernia is recommended earlier rather than later.
Open repair using the nonmesh McVay
technique is preferred to treat complicated femoral hernias; there is an
increased risk for recurrence due to tension at the suture line, however. The use
of mesh reduces the chance of recurrence. Various mesh repair techniques can be
used, except for the Lichtenstein repair, which does not cover the femoral ring.
Laparoscopic repair of femoral hernias is also possible; both the transabdominal
preperitoneal hernia repair and the totally extraperitoneal hernia repair can
be used.
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