Metachronous inguinal hernias in children

Introduction: Hernia developing in the contralat­ eral groin in children presenting with unilateral inguinal hernia is a recognized problem. There is no consensus regarding the need for exploration of the contralateral groin in children presenting with a unilateral hernia. Objectives: To study the incidence of meta­ chronous inguinal hernia and to assess the justifi­ ability of not exploring the contralateral groin. Methods: All children operated for unilateral inguinal hernia in our unit between April 1995 and April 1998 were asked to present themselves for review in April 2000. Results: Hundred and forty six of the 247 children operated turned up for review. There were 96 (66%) boys and 50 (34%) girls. The ages ranged from 54 days to 11 years. Eight of the 50 girls (16%) and 14 of the 96 boys (15%) developed meta­ chronous inguinal hernias. Metachronous hernias developed in 5 of the 42 children (12%) who had their first operation at the age of 2 years or earlier. Conclusion: Routine exploration of the contralat­ eral groin of all children cannot be justified as only 15% developed metachronous hernias. Some sur­ geons are selective and explore the contralateral groins of all girls and in boys under 2 years. This policy also could not be justified as the incidence of metachronous hernia was equal in both sexes and was not higher in children of 2 years or younger. We recommend exploring the symptomatic groin only.


Introduction
Hernias developing in the contralateral groin (metachronous hernia) in children presenting with a unilateral inguinal hernia is a recognized prob lem. There is no consensus regarding the man agement of the asymptomatic groin in children presenting with a unilateral inguinal hernia. Many current surgeons advocate a selective rather than a routine exploration of the contralateral groin. However it has been our policy and of some others to operate on the symptomatic groin only.
The objectives of our study were to evaluate the incidence of a contralateral inguinal hernia (metachronoushemia) developing in the children we had operated on for a unilateral hernia and to assess the justifiability of not exploring the contralateral groin.

Methods
All children operated for unilateral inguinal hernia in the University Surgical Unit of the Lady Ridgeway Hospital for Children between April 1995 and April 1998 were asked to present them selves for review in April 2000. They were exam ined by one of the authors. Children with ascites, ventriculoperitoneal shunts and connec tive tissue disorders were excluded from the study.

Results
Two hundred and forty seven children were operated for a unilateral inguinal hernia between April 1995 and April 1998. Hundred and forty six (60%) children presented for review. There were 96 (66%) boys and 50 (34%) girls. The ages ranged from 54 days to 11 years. Table 1 shows the age distribution at the time of the first operation.

I. Lecturer, 2. Senior Lecturer, University Surgical Unit, Faculty of Medicine,University of Colombo and Lady Ridgeioay
Hospital for Children, Colombo 8, Sri Lanka. At review 22 children (15%) had a subsequent herniotomy in the contralateral groin, or presented with a metachronous hernia. Eight of these were girls and 14 were boys, making the incidence of metachronous hernia in girls 16% and in boys 15%. The distribution of metachronous hernia according to the age at the first operation is shown in Table 2. Five of the 42 children (12%) who had their first herniotomy at the age of 2 years or earlier developed metachronous inguinal hernias.  (1). Exploring the contralateral groin in addition to prolonging the surgery also puts the vas deferens and the testicular vessels of the male child at risk. Therefore most surgeons have given up routine exploration of the contralateral groin. We had a 15% incidence of metachronous hernia, which jus tifies the position against routine exploration of the contralateral groin. Other factors such as female sex, left sided primary hernia, and age under 2 years have been implicated by different workers as predictors of metachronous hernia (1). Such findings have led to the recommendation of a selective approach to contralateral groin explora tion. A standard text book of paediatric surgery recommends contralateral groin exploration in all males under 2 years and in females of any age (1). However our study demonstrated very close and low incidence of metachronous hernia in girls and boys, 16% (8 out of 50) and 15% (14 out of 96) respectively. Therefore we cannot justify the rec ommendation of exploring the asymptomatic groin of all girls. Exploring the contralateral groin of boys under 2 years was also difficult to justify as our study revealed an incidence of metachronous hernia of only 12% in children who were 2 years or younger at the first operation. These results were similar to those of 2 recently published series. Kemmotsu et al in a study The Ceylon journal of Medical Science involving 1001 children aged 1 to 11 years found an overall incidence of metachronous hernia de veloping in 11.6% (3). Ballantyne et al in a study of 181 infants detected metachronous hernia in only 7.7% (4). Both these studies show no change in the incidence of metachronous hernia with age, sex or the side of the primary hernia. Both studies concluded by not recommending contralateral groin exploration.
Therefore in the Sri Lankan setting where access to laparoscopy and pneumoperitonography is limited we recommend the policy of operating only the symptomatic groin in children present ing with a unilateral inguinal hernia.