Development of surgical protocol for implantation of tracheal prostheses in sheep

This article documents experiments performed in ewes to design an artificial larynx. The artificial larynx is composed of a hollow, porous tube that elongates the trachea and is capped with a valve that acts as a laryngeal sphincter. Through an industrial collaboration, our team developed a porous biomaterial that can be colonized by cervical tissues. This biomaterial has been used in animals to replace part of the trachea, but it is meant to eventually substitute for laryngeal cartilage. The tracheal prosthesis is a hollow cylindrical tube composed of titanium microbeads. We performed a study in large animals to establish an optimal surgical protocol for tracheal replacement in humans. The study included 11 sheep (n = 11) and compared 5 methods of implantation. We successfully established an optimal three-step surgical protocol to make the porous-titanium tracheal prosthesis functional: (1) large lumen endoprosthetics, (2) colonization by the peripheral tissues, and (3) endoprosthetic epithelialization. This study is the first step in developing an artificial larynx because it successfully identifies a biomaterial capable of extending the trachea to allow it to open at the junction of the upper aerodigestive tracts.