LARYNOOTRACHEAL TRAUMA 195 If there is a linear fracture down the thyroid then the aim of treatment is to reduce the fracture and to prevent the anterior ends of the vocal cords from joining together to form a web. This is done by using a piece of 0-18 mm thick tantalum sheeting, cut to the shape shown (Fig. 98), which is placed keel end first between the cords, and fixed by pressing the flanges over the thyroid Fig. 98. McNaught keeL Fig. 99. Solid stent mould, made to the shape of the larynx, used to reform the shattered larynx. cartilage which is wired. This is called a McNaught keel and is left in place for 5 weeks. The neck, but not the larynx, must be reopened to remove it. When the thyroid cartilage is shattered the same principles are used but the larynx must be refashioned around a solid stent mould, which is made to the shape of the larynx (Fig. 99), wired in place and left for at least 8 weeks. This can be removed endoscopically. Fractures of the hyoid are much easier to treat. The fracture is exposed and the piece of bone on either side of the fracture is removed leaving a gap in the hyoid which causes no functional problem.