gms | German Medical Science

Objectives/Interrogation: Peripheral nerve physiology and regeneration has been observed and investigated in literature but surgical applications to reconstruct and restore motor or sensory functions are still in a developmental phase. Recent surgical attempts to treat proximal nerve injures include direct nerve restoration, transfer, and autografting measures with favorable results. In this report, we present a completely new tubulization method, the amnion muscle combined graft (AMCG) technique, that consists in the combination of the human amniotic membrane hollow conduit with autologous skeletal muscle fragments for repairing the substance loss of peripheral nerves and recover both sensory and motor functions.

Methods: In a series of patients with loss of substance of the median nerve ranging 3-5 cm at the wrist, excellent results graded as S4 in two cases, S3+ in two cases, and S3 in one case; M4 in four cases and M3 in one case were achieved. Moreover, we evaluate the final outcome of nerve regeneration morphologically and functionally, across the AMCG compared to nerve autograft in fourteen Wistar rats. Functional results were evaluated at 30, 60 and 90 days performing grasping tests. Morphological and stereological analyses were performed at T90 using high-resolution light microscopy and design-based stereology.

Results and Conclusions: Functional recovery was observed in both groups with AMCG conduits group showing lower values and a regeneration of median nerves with more myelinated fibres with the same axon size, but thinner myelin than the autograft group. Though the autograft remains the gold standard to restore wide nerve gaps, the AMCG conduit has proved to be effective in enabling nerve regeneration through a critical rat's nerve gap of 15 mm. No iatrogenic damage due to withdrawal of a healthy nerve from donor site was observed.

The amnion muscle combined graft (AMCG) conduits showed good clinical results in peripheral nerves gap repair. These results seem attributable to the biological characteristics of human amniotic membrane: Pluripotency, anti-inflammatory and low immunogenicity. The use of autologous sural nerve grafts is still the current gold standard for the repair of peripheral nerve injuries with wide substance losses, but with a poor rate of functional recovery after repair of mixed and motor nerves, a limited donor nerve supply, and morbidity of donor site.