Experimental study of the mental nerve regeneration: Comparison among primary and secondary microsurgical repair techniques [Studio sperimentale sulla rigenerazione del nerve mentoniero: Confronto tra tecniche microchirurgiche di riparazione primaria e secondaria]

The Authors propose to evaluate the differences between primary (immediately after the lesion) and secondary (three months after the lesion) reparative microsurgical techniques, involving the only sensitive trigeminal branch (mental nerve). It is pointed out the choice between the use of sensitive (mental nerve) or mixed (common peroneal nerve) auto-grafts to repair secondly lesions with loss of substance. The studied groups formed by inbred rats have been: primary neurorrhaphy, sensitive auto-grafting and mixed auto-grafting; secondary neurorrhaphy, sensitive auto-grafting and mixed auto-grafting. The function's recovery has been studied with neurophysiological techniques (the thresholds of electrically and mechanically evoked head withdrawal) and histochemistry (HRP-WGA labelled trigeminal ganglion cells). The results show that the neurorrhaphy is the best reconstructive technique only when it is primary. The best results in the primary auto-grafting groups have been reached with the sensitive auto-grafting. No particular differences have been shown in the secondary repair groups. The secondary repair techniques haven't shown important differences among themselves, all reporting encouraging results. This study points out how the trigeminal ganglion cells preserve regenerative capacities also a long period after the lesion, and how it is sufficient to connect correctly the nerve stumps to restore the function independently from the utilized technique