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

Non-specific re-innervation of target organs caused by misdirected axonal g rowth at the repair site is regarded as one reason for a poor functional ou tcome after peripheral nerve transsection and repair. This study investigat es 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 suture s (A x 6), fascicular repair of tibial and peroneal nerves respectively (B x 8), and the same as in group B, but separating both nerves using an Integ ra (R) -sheet with silicone (C x 8), or Integra (R) without silicone (D x 8 ). As control, solely the tibial nerve was transsected and repaired (E x 5) . Final investigations after 4 months revealed that in group C, 50% of the In tegra (R) -silicone sheets were dislocated. No dislocation was found in gro up D. Muscle contraction force of the gastrocnemius muscle was significantl y higher in group E as compared to all other groups. However although not s ignificant, group D showed a consistently higher muscle contraction force t han groups A, B, and C. Histology in groups A, B, and C with dislocated she ets demonstrated multiple axons growing from the tibial to the peroneal ner ve and vice versa. In groups D and E, no such axonal growth was visible. Th ese findings were confirmed by a significantly higher rate of specific rein nervation of the soleus muscle using sequential retrograde double labelling technique. Results of this study suggest that an artificial sheet such as Integra (R) bears the potential of preventing aberrant re-innervation between repaired adjacent nerves resulting in improved motor recovery. Clinically, this tech nique may be of importance for brachial plexus, sciatic nerve, and facial n erve repair.