Interpositional Jump-Graft Using a Hybrid Artificial Nerve-Conduit with Adipose-Derived Stem Cells for Rat Facial Nerve Paralysis Model

Purpose: Facial nerve paresis such as Bell’s palsy and Hunt`s syndrome appears suddenly in healthy individuals and recovers by conservative treatments in some cases. However, a non-recovery situation considerably reduces the quality of life of patients. Interpositional jump-graft (IPJG) technique with the hypoglossal nerve for supercharging can be applied in the case and becomes the subjects of many clinical reports. However, in IPJG case, an autologous nerve is required, and the donor site morbidity is unavoidable. Bio-degradable nerve conduits are made from polyglycolic acid (PGA) and used recently without donor site complications after providing autologous grafts. Hybrid artificial nerve conduits with adipose-derived stems cells (ASCs) also attract attention as a nerve-regeneration enhancing agent. This study used hybrid artificial nerve conduits to obtain IPJGs closely similar to autologous nerve grafts.

Materials and Methods: A ligature clip was used to crush the facial nerve trunk, thereby creating a partial facial nerve paresis model. A 10-mm-long biodegradable artificial nerve-conduit containing ASCs used to create an IPJG between the facial nerve trunk and the hypoglossal nerve (Hybrid PGA group). Thirteen weeks after the surgery, the outcome was physiologically compared with conventional IPJG with autograft using the greater auricular nerve (autograft group), non-ASCs artificial nerve group (PGA group) and non-treated group (control group).

Results: Compound muscle action potential amplitude was highest in the autograft group (4352 ± 1587 μV), followed by the Hybrid PGA group (3224 ± 1778 μV), PGA group (1960 ± 445 μV), and then control group (687 ± 490 μV). In the Hybrid PGA group, amplitude was significantly higher than in the PGA group (P < 0.05). Myelin thickness of autograft group (0.79 ± 0.03 μm) was significantly higher than that of Hybrid PGA group (0.68 ± 0.29 μm) (P < 0.01), and that of Hybrid PGA group was significantly higher than that of PGA group (0.44 ± 0.03 μm) (P < 0.01). Autograft, PGA, and Hybrid PGA groups showed a myelinated nerve regeneration with double innervation in hypoglossal and facial nerve nuclei for vibrissal muscle.

Conclusion: This study found that a conventional IPJG technique with an autologous nerve can be substituted with a hybrid artificial nerve-conduit with ASCs in a rat model with partial facial nerve paresis.