Specificity of reinnervation and motor recovery after interposition of an artificial barrier between transected and repaired nerves in adjacency : an experimental study in the rat

• Non-specific re-innervation of target organs caused by misdirected axonal growth at the repair site is regarded as one reason for a poor functional outcome after peripheral nerve transsection and repair. This study investigates the rate of aberrant re-innervation and its influence on motor recovery in the rat sciatic nerve using artificial sheets as barrier between tibial and peroneal nerves.The sciatic nerve was transsected and repaired as follows: epineural sutures (A × 6), fascicular repair of tibial and peroneal nerves respectively (B × 8), and the same as in group B, but separating both nerves using an Integra®-sheet with silicone (C × 8), or Integra® without silicone (D × 8). As control, solely the tibial nerve was transsected and repaired (E × 5).Final investigations after 4 months revealed that in group C, 50% of the Integra®-silicone sheets were dislocated. No dislocation was found in group D. Muscle contraction force of the gastrocnemius muscle was significantly higher in group E as compared to all other groups. However although not significant, group D showed a consistently higher muscle contraction force than groups A, B, and C. Histology in groups A, B, and C with dislocated sheets demonstrated multiple axons growing from the tibial to the peroneal nerve and vice versa. In groups D and E, no such axonal growth was visible. These findings were confirmed by a significantly higher rate of specific re-innervation of the soleus muscle using sequential retrograde double labelling technique.Results of this study suggest that an artificial sheet such as Integra® bears the potential of preventing aberrant re-innervation between repaired adjacent nerves resulting in improved motor recovery. Clinically, this technique may be of importance for brachial plexus, sciatic nerve, and facial nerve repair.

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