Intracordal Injections With Allogenic Cartilage in a Canine Paralyzed Vocal Fold Model: Long-Term Results

Objective To determine whether detergent treated allogenic cartilage can be used as a substitute for autologous cartilage in a canine paralyzed vocal fold model. Material and Methods Twelve canines underwent a right recurrent laryngeal nerve resection with injections of allogenic auricular cartilage (harvested 7 days prior, treated with detergent, and minced), with a hyaluronic acid hydrogel (0.2آ mL) into the right thyroarytenoid muscle, and with a pressure syringe under direct laryngoscopy. Two animals were sacrificed and larynges removed at each time point: 1-, 3-, 6-, 12-, 18-, and 24-months post injection. Hematoxylin-eosin and immunohistochemistry for expression of major histocompatibility complex-II (MHC-II) antigen was measured to assess histomorphology and gross volume and loss of antigenicity of the injected allogenic cartilage. Results Injected allogenic cartilage maintained its position and volume in the vocalis muscle throughout 24 months. Cartilage was characterized with empty lacunae indicating possible loss of viability. Fibrotic changes were noted in the surrounding cartilage. MCH-II antigen was not identified in the perichondrium and/or cartilage. Inflammatory reaction, granuloma, or foreign body reaction was not observed at any time point. Conclusions These preliminary results suggest that allogenic auricular cartilage grafts treated with detergent are well tolerated and may be an effective material for volumetric augmentation in the paralyzed vocal fold.