Delay of denervation atrophy by sensory protection in an end-to-side neurorrhaphy model: a pilot study

Object: Temporary sensory innervation delays the atrophy process. A major disadvantage of most experimental models is that sensory-protected muscles must be denervated a second time to allow reinnervation by the affected nerve. The aim of this study was to assess the effect of sensory protection on denervated gastrocnemius muscle in an end-to-side neurorrhaphy model, in which denervated muscles may be preserved until axons of the native nerve reach their target without the necessity for a second operation.

Methods: The tibial nerve of 24 female Lewis rats was transected. Twelve animals acted as the controls. In the other 12 animals, the end of the sural nerve was connected to the side of the distal tibial nerve stump (sensory protection group). At 5 and 10 weeks, wet gastrocnemius muscle weight was reported as a ratio of the operated to the unoperated side. For histological analysis, muscle samples were rapidly frozen and sections were stained with haematoxylin and eosin, Oil Red O stain and modified Gomori trichrome stain.

Results: The difference between the sensory protection group and the control group was statistically significant at 5 (0.36±0.01 and 0.29±0.01, respectively; p<0.001) and 10 weeks postoperatively (0.28±0.01 and 0.19±0.00, respectively; p<0.001). Histological observations revealed that sensory-protected muscles underwent less atrophy.

Conclusion: Sensory protection delays atrophy in an end-to-side neurorrhaphy model.