Extrusion forces of resorbable tacks and titanium screws in laryngeal chondrosynthesis

Laryngotracheal trauma, partial laryngectomy and phonosurgery may necessitate reconstruction of the cartilaginous skeleton to ensure the quality of respiration and voice. The present report focuses on initial experience gained with a new resorbable material for plates and tacks that allows chondrosynthesis of the laryngeal skeleton. A comparison of the extrusion forces necessary to pull out the resorbable tacks versus conventional titanium screws and the degree of deformation until failure represent the experimental parameters of reconstruction quality under investigation. The PolyMax system (Synthes, Oberdorf, Switzerland) was used in a human cadaver dissection. Sixteen tacks with a diameter of 1.5 mm and sixteen titanium screws with a diameter of 1 mm were placed into the two wings of the thyroid cartilage. Extrusion forces and the degree of deformation occurring until mechanical failure of the device-body interface were measured for the two types of fixation systems. Results in N and mm were compared using a two-sided Wilcoxon test. Neither variable differed significantly between the two groups. However, within the two groups, the necessary strength to pull the tacks or the screws out of the cartilage varied markedly depending on both the inhomogeneous quality of cartilage and the degree of calcification. The PolyMax system with the tacks is recommended as an effective tool for reconstructing the cartilaginous skeleton of the larynx and the trachea with the inherent advantage of resorption as well as avoidance of a second surgery for material removal.