A collagen-coated PGA conduit for interpositional-jump graft with end-to-side neurorrhaphy for treating facial nerve paralysis in rat.

Abstract

PURPOSE: This study investigated the potential of collagen-coated polyglycolic acid (PGA) tube with interpositional jump graft (IPJG) in rat. MATERIALS AND METHODS: A total of 16 Lewis rats were used in this study. Facial nerve paralysis was created by ligating facial nerve trunk with a ligature clip. The rats were divided into 3 groups. Nerve conduit group (n&#x2009;=&#x2009;6) were treated by IPJG with collagen-coated PGA tubes between the facial nerve trunks and the hypoglossal nerves. Autograft group (n&#x2009;=&#x2009;6) were treated by IPJG with the greater auricular nerves. As the control group (n&#x2009;=&#x2009;4), non-treated-model rats with facial nerve paralysis were used. The number of myelinated fibers, fiber diameter, axon diameter, myelin thickness, and g-ratio, were analyzed histologically at 13 weeks after surgery. Compound muscle action potential (CMAP) and retrograde tracing were measured. RESULT: Although the number of myelinated fibers in autograft group (1957&#x2009;&#xb1;&#x2009;775) had significantly higher than that of nerve conduit group (90&#x2009;&#xb1;&#x2009;41, P&#x2009;<&#x2009;.05), the nerve conduit group showed the regeneration of myelinated nerve axons. CMAP amplitude values of the autograft (4706&#x2009;&#xb1;&#x2009;1154 &#xb5;V) and the nerve conduit groups (4119&#x2009;&#xb1;&#x2009;1397 &#xb5;V) were significantly higher than that of the control group (915&#x2009;&#xb1;&#x2009;789 &#xb5;V, P&#x2009;<&#x2009;.05). Retrograde tracing confirmed the double innervation of mimetic muscles by the facial and hypoglossal nucleus in both groups. CONCLUSION: This study showed histologically and physiologically the superior effectiveness of performing IPJG with a collagen-coated PGA conduit in a rat model.