How to deal with the variability of peripheral nerve lesion patterns after inguinal herniotomy? A descriptive approach for a new terminology in clinical practice.

Background: Inguinal hernia is one of the most common visceral surgical conditions in industrialised countries. The aim of the present observational clinical study was to investigate the dermatome patterns after nerve injury following inguinal hernia surgery and to demonstrate the marked individual anatomical and topographical variability of peripheral nerves in the inguinal region.

Methods: 220 patients were followed up for one year after inguinal herniotomy. Surgical treatment was performed either with tension-free mesh techniques or open according (Lichtenstein).

Results: One year after inguinal herniotomy, 25 patients (11.4 %) reported postoperative symptoms. Of these, 15 patients showed evidence of a distinct nerve lesion. The results of the clinical neurological examination sometimes differed considerably from the subjective perceptions of the patients. In addition, a marked individual variability in the dermatomes of surgically lesioned nerves was found, with discrepancies to the classical and conventional dermatome data in textbooks.

Conclusions: This study has shown that it is hardly possible to assign a specific lesional inguinal dermatome to a specific nerve, as nerves show a large individual variability in their anatomical, topographical location and thus in their dermatome boundaries. Therefore, we propose a descriptive approach to the terminology of peripheral inguinal nerve lesions using common regional landmarks. This will avoid a potentially erroneous dermatome assignment to a certain nerve and facilitate the reproducibility of lesion descriptions between different observers, thus facilitating communication in clinical practice.