Histology of injected autologous fascia in the paralyzed canine vocal fold

Objective: To evaluate the histology of minced and injected autologous fasc ia graft in the augmentation of unilateral vocal fold paralysis. Study Desi gn: Prospective study using a canine model, Methods: Nine dogs were operate d. At first, a piece of fascia was harvested hom fascia lata and minced int o tiny chips with a scalpel, Cutting off a section of the recurrent nerve p aralyzed the right vocal fold, The minced fascia-paste (0.1 mL) was injecte d using a pressure syringe into the paralyzed thyroarytenoid muscle under d irect laryngoscopy, Two animals were killed at 3 days, one at 10 days, thre e at 6 months, and three at 12 months postinjection, Each dog underwent lar yngectomy and serial coronal sections of paraffin blocks from the posterior part of the vocal folds were made. Results The dogs experienced no complic ations perioperatively or during follow-up. Under microscopy, muscle of the paralyzed vocal fold was atrophied in comparison to the contralateral cont rol, There was an acute inflammatory reaction induced by the graft. This di d not exist in the specimens taken at 6 and 12 months, No extensive edema, areas of necrosis, or formation of granulomas was seen at any time. Maturat ion of the graft was characterized by active collagen remodeling up to 12 m onths. At that time the graft consisted of firm, condensed fibrous tissue, Scar formation around the graft was moderate, and the subepithelial layer o f the vocal fold remained undisturbed. Each graft consisted of singular for eign bodies from the polyamide mincing plate We cannot exclude that their p resence would have had an impact on the final architecture of the graft. Co nclusion: In a canine vocal fold, the fi ee fascia graft is well tolerated and after 12 months a well organized, collagen rich tissue is seen on histo logical sections. The findings are in accordance with clinical studies appl ying free fascia grafts.