Healing of abdominal incisional hernia in infant rats

Incisional hernia following major laparotomy in adult humans occurs in 5 per cent of cases. Spontaneous healing of such hernias does not occur. We have devised a model for producing abdominal wall incisional hernia in the rat by dividing the linea alba subcutaneously through a small transverse skin incision. In adult rats (n = 17), an incisional hernia formed and progressively increased in size over 32 weeks. In 3-week-old infant rats (n = 17), all developed herniation immediately. In eight rats, these hernias progressively increased. In three, the hernias were healed at the third week, but recurred at the fourth, eighth and 12th weeks, respectively. In the remaining six animals, the hernias healed spontaneously at 3 weeks and remained healed. A similar observation of spontaneous healing of incisional hernias in children has been reported in one clinical paper. This animal model provides a useful means of studying the clinical difference between adult and infant with respect to incisional hernia.