Histology and Stroboscopic Findings after Injection of Artecoll(R) and Restylane(R) into Paralyzed Canine Vocal Fold: in vivo Canine Study

BACKGROUND AND OBJECTIVES: The aims of this study are to introduce Artecoll and Restaylane, that have been available for facial augmentation, as new materials for injection laryngoplasty, to investigate the mucosal wave of true vocal folds after the injection of these two materials into the true vocal fold, and to assess its biocompatibility and durability. SUBJECTS AND METHOD: After complete paralysisof the right recurrent laryngeal nerve of 6 Beagle dogs, the dogs were divided into the Artecoll injection group and the Restylane injection group, and Artecoll or Restylane was injected into vocalis muscle and vocal ligament. The recurrent laryngeal nerve of the opposite side was stimulated, the posterior commissure was sutured, and the mucosal wave of true vocal folds was examined by stroboscopy in in vivo canine study 1, 3, and 6 months after the injection. And, histopathological change of the injected materials after total laryngectomy was examined by hematoxylin and eosin (H & E) staining and masson trichrome staining. RESULTS: In both the Artecoll injection and the Restylane injection groups, the mucosal wave of true vocal folds was detected by stroboscopic examination until 6 months after the injection, and the difference of the mucosal wave of true vocal folds between these two groups was difficult to detect. Histological studies revealed that the injected materials remained in the vocal ligament and vocalis muscle and theses two materials were resorbed with time, Artecoll showing less resorption. These two materials were biocompatible and, particularly, Restylane showed less foreign body reaction. CONCLUSION: Since both Artecoll and Restylane are biocompatible and durable, they areconsidered as the suitable material for injection larygoplasty, and additional long-term studies are required