Inguinal hernia is a protrusion of abdominal cavity into the inguinal canal. It has a very close relation with premature infants and affecting up to 25% of male infants. Overall incidence is more common in male rather than female gender. Previous study showed that the testicles only descent into the scrotum after 32 completed week gestation follows by the contraction of the processus vaginalis at the inguinal canal. As addition, studies revealed that premature infants having IH were more likely to have had lower gestational age, lower birth weight and required prolonged ventilator assistance.
There are 2 types of inguinal hernia; first is indirect inguinal hernia and second is direct inguinal hernia. Indirect inguinal hernias are congenital hernias. It is more common in males due to the way they develop in the womb. In male fetus, the spermatic cord and both testicles usually descend from intra abdominal cavity into the scrotum through inguinal canal. The entrance of the inguinal canal at the inguinal ring should close just after birth. However, it may not happen sometimes, particularly in premature infant. This will lead to abdominal weakness and allow fat or part of the small intestine slides through into the inguinal canal causing a hernia. The different in females is the indirect inguinal hernia is caused by the female organs or the small intestine sliding into the groin through a weakness in the abdominal wall. There is no canal involve.
Meanwhile, direct inguinal hernia is caused by connective tissue degeneration of the abdominal muscles which weaken during adulthood. It develops gradually because of the continuous stress of the muscles. Direct inguinal hernias can only occur in males. These hernias usually slide back and forth spontaneously and can often be reduced back into the abdomen with gentle massage.
The symptoms of inguinal hernia include a small bulge in one or both sides of the groin that may increase in size and disappear when lying down. Males can present as a swollen or enlarged scrotum. There is often associated with discomfort or sharp pain especially during straining, lifting, or exercising that usually improves when resting. In premature infant, it is mainly the clinical examination as the baby cannot obviously complain any pain. Excessive cry may suggest pain. The hernia may become incarcerated or strangulated. Incarcerated means the hernia cannot be reduce back to abdominal cavity and may later lead to strangulated hernia that require emergency operation. If surgery is not performed right away, the condition can become life threatening. The affected intestine may die and need resection. These two complications are rarely seen in infants.
In term of treatment, inguinal hernia is usually surgically managed. The operation mainly divided by two; open surgery or laparascopy. For adult, the surgeon will do herniorraphy or hernioplasty while in infancy they will do herniotomy. Traditionally in herniorraphy, the weak spot in the muscle wall will be repaired by sewing the edges of the healthy muscle tissue together. Today, a mesh patch (or patches) of synthetic material are now widely use. It will be sewn over the weakened area in the abdominal wall after the hernia is reduced back in the abdominal cavity, hence we get the term ‘hernioplasty’. In herniotomy, the patient processus vaginalis will be excised and ligated. Generally, it will be unnecessary to perform formal repair of the abdominal wall.
References:
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