Letter to the editor: "Incidence of contralateral occult inguinal hernia found at the time of laparoscopic trans-abdominal pre-peritoneal (TAPP) repair" by Griffin et al. (Hernia 14:345-349, 2010).

Dear Editor,

We read with great interest the recent article by Griffin et al. [1]. The authors studied the incidence of occult contralateral hernias during trans-abdominal pre-peritoneal (TAPP) repair and found an incidence of 22% in patients scheduled for unilateral repair. We would like to congratulate the authors on their work, but we have some criticisms to be discussed.

We noticed that a distinct definition of ‘occult hernia’ is lacking. Did the authors actually mean a patent processus vaginalis (PPV) or did they find a true herniation of abdominal content through the open processus? If it really concerned herniations, we missed the differentiation between direct and indirect hernias. Moreover, it must be concluded, then, that 22% of the patients had been misdiagnosed by clinical evaluation. We, therefore, expect the authors to mean PPV when using the term ‘occult hernia.’

We ourselves have studied PPV extensively. In an adult population undergoing laparoscopic surgery for treatment other than hernia repair, we found an incidence of 12% [2]. In a follow up study on the same study population 5 years later, we also found that patients with a PPV have a higher chance of developing an indirect hernia than patients with an obliterated processus vaginalis, 12 vs. 3% [3].

Since the majority of people with PPV will not develop hernias, whereas some people without PPV will, we think that the relationship between a PPV and the development of a hernia is not at all crystal clear. We, therefore, feel that care should be taken when casually repairing asymptomatic PPVs just because the contralateral side is being repaired. In this respect, it also has to be considered that a significant proportion of hernias, if having developed at all, will remain asymptomatic and will probably need no operation at all. Finally, the operating times are longer, the costs are higher, and, as with every operation, laparoscopic hernia repair is still not without complications [4].