ABSTRACT
BACKGROUND AND OBJECTIVES: Recurrent laryngeal nerve (RLN) damage commonly occurs from a thyroid surgery and causes communication impairment, aspiration and dysphagia. The purpose of this study is to develop a polycaprolactone (PCL) nerve guide conduit (NGC) coated with conductive materials for facilitating regeneration from the RLN defects and to evaluate the usefulness of the PCL NGC coated with conductive materials in a rabbit model. MATERIALS AND METHODS: The PCL NGCs coated with conductive materials were fabricated for this study. The types of conductive materials were single-walled carbon nanotubes (SWNTs) and poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) which were coated on the PCL NGCs by layer-by-layer (LBL) assembly techniques. An 8-mm segment of left RLN was resected in 24 New Zealand white rabbits. Three different NGCs (PCL and PCL with two conductive materials) were interposed between both stumps and fixed with suture. For the assessment of functional regeneration, the vocal cord mobility was observed using endoscopic system after RLN stimulation, and the motion change was analyzed. The atrophies of thyroarytenoid muscle and nerve growth were evaluated by Hematoxylin-Eosin (H-E) and toluidine blue (T-B) staining, respectively. Immunohistochemical study using anti-neurofilament, S-100 staining was further performed to evaluate the nerve regeneration. RESULTS: In endoscopic evaluation, the group with conductive PCL NGCs showed an improved tendency of vocal cord mobility compared to that of the other group. Nerve growth was observed with the time for 8 weeks in all groups and immunohistochemical staining revealed the expression of neurofilament and S-100 in regenerated nerve in all groups. The atrophies of thyroarytenoid muscle in the group with conductive PCL NGCs was also shown to be decreased compared to that of the nonconductive PCL NGC group. CONCLUSION: The study shows that PCL NGC coated with conductive materials appears to be a good alternative option for the repair and regeneration of RNL damages.