Can end-to-side neurorrhaphy bridge large defects? An experimental study in rats

This study was undertaken to evaluate collateral sprouting capability in an end-to-side repair model with long regenerative distance. Forty-five rats were used and divided into four groups, according to the reparative procedure following peroneal nerve division: (A) "double" end-to-side neurorrhaphy with a regenerative distance of 0.6 cm; (B) "double" end-to-side neurorrhaphy with a regenerative distance of 1.2 cm; (C) end-to-end neurorrhaphy; and (D) nerve stumps buried into neighboring muscles. In all animals the contralateral healthy side served as a control. Functional assessment of nerve regeneration was performed at intervals up to 5 months using the Peroneal Function Index (PFI). Evaluation 150 days after surgery included peroneal and tibial nerve histologic and morphometric examination and wet weights of the tibialis anterior muscle. Functional evaluation and axonal counting data demonstrated that there was no statistically significant difference between groups A and B, or between groups A and C. There was no functional or histologic evidence of donor nerve deterioration. In conclusion, the present study confirms that "double" end-to-side neurorrhaphy may be useful for the repair of divided human nerves with long gaps.