Soft tissue response in the rabbit larynx following implantation of Lactosorb (PLA/PGA copolymer) prosthesis for medialization laryngoplasty

This project is designed to provide initial data regarding the use of polylactic acid/polyglycolic acid (PLA/PGA) copolymer (“LactoSorbâ€‌ [Walter Lorenz Corp]), an alloplastic, resorbable material, as a prosthesis in an animal model of vocal fold medialization. Fifteen New Zealand white rabbits were utilized for left medialization laryngoplasty with LactoSorb implants after undergoing left recurrent laryngeal nerve section. At 1, 3, 6, and 9 months, the rabbits were sacrificed and their larynges were evaluated both grossly and histologically for tissue response to, and resorption characteristics of the implant, tissue cellularity, maintenance of vocal fold medialization, and airway patency. Additionally, 4 rabbits were used as controls, implanted with silicone rubber medialization implants, and sacrificed at 9 months for comparison. One rabbit underwent no surgery and was likewise used as a control. Grossly, no airway obstruction was noted, and no extrusions of the implants occurred. The LactoSorb implant maintained medialization in each group of sacrificed rabbits. Histologic findings revealed a very discrete, fibrous capsule around the implant in the 1- and 3-month rabbits, and the LactoSorb was still grossly visible. At 6 months, the thin fibrous capsule partially remained; at 9 months, the capsule was no longer evident, and the implant was no longer grossly visible. Endoscopic findings at the time of sacrifice in those rabbits implanted with silicone rubber included grossly patent airways with maintenance of medialization. In the rabbits implanted with silicone rubber, the histologic findings are similar to those described elsewhere.1 LactoSorb, because of its intermittent resorption rate, could offer an ideal alternative to currently utilized temporary, or resorbable, materials, and as such will hopefully prove an invaluable tool in the laryngologistʹs treatment planning and surgical repair of the patient with a paralyzed vocal fold.