Comparison of reinnervation for preservation of denervated muscle volume with motor and sensory nerve: an experimental study.

Prevention of the atrophy of denervated muscles is essential for a good outcome in facial contouring and oral reconstruction. In this study, we compared the effectiveness of end-to-end and end-to-side neurorrhaphy of the motor nerve, and end-to-end neurorrhaphy of the sensory nerve, all of which are frequently used in such reconstruction for the prevention of muscle atrophy. Wistar rats were divided into four groups: group 1, motor nerve division of semi-membranosus without repair; group 2, motor nerve division and end-to-end coaptation to the saphenous nerve; group 3, motor nerve division and end-to-side coaptation to the sciatic nerve; and group 4, motor nerve division and end-to-end repair. Measurement of semi-membranosus volume, histological evaluation and staining of neuromuscular junctions that were carried out 3 months postoperatively revealed that muscle volume preservation was larger in groups 3 and 4 than in the other two groups (p<0.05), but slightly superior in group 4 (p<0.05). There was no statistical difference between groups 2 and 1; histologically, muscle architecture was better preserved in group 2 than in group 1; reactivation of the neuromuscular junctions was observed in all except group 1. End-to-side repair of motor nerves is one of the better options for the preservation of muscle volume when end-to-end nerve repair is not indicated. Sensory protection may also provide some advantages in the preservation of muscle volume.