Experimental study on an airway prosthesis made of a new metastable β-type titanium alloy

Abstract

Surgical treatment of a subglottic stenosis can lead to a cricoid cartilage resection, cervical trachea resection, or both that has to be reconstructed with an artificial prosthesis. However, there is at present no standard treatment in the numerous reconstruction procedures, and many prostheses encounter inflammatory rejection and mechanical constraint problems. A porous, metastable β-type titanium alloy prosthesis was developed to improve subglottic rehabilitation. We have designed a porous type of airway prosthesis made of porous metastable β-type titanium alloy. We used this prosthesis (20 mm in length) to reconstruct the cricoid cartilage and the first tracheal ring in 10 mongrel dogs and evaluated its efficacy. One dog died of an accident with anesthesia at 1 week, 1 dog died of pneumonia about 1 month after the operation, and 6 dogs were killed between the third and eighth months after the operation. At death, all the prostheses had become completely incorporated into the host tissue. Endoscopic examination showed no airway obstruction for a postoperative period of 3 to 8 months in 8 dogs. Granulation was observed in 4 cases, and the porous, metastable β-type titanium alloy plate was exposed in 1 case, but these dogs were asymptomatic. Light microscopic and electron microscopic analysis showed a normal mucous membrane growth on the surface of the prosthesis and no visible granulation tissue in the reconstructed cricoid and tracheal cavity. This airway prosthesis provided good results in canine cricotracheal reconstruction, and this study presents the possibility of successful reconstruction of the cricoid and trachea with epithelial regeneration.