Experimental and clinical evaluation of laryngeal chondrosynthesis

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.

Titanium vocal fold medializing implant: introducing a novel implant system for external vocal fold medialization

With the increasing worldwide spread of the Isshiki technique for external vocal fold medialization, some disadvantages and limitations have also emerged. and an increasing demand for a ready-made and standardized implant system can be observed. For this reason. I started experimental and clinical investigations with the goal of replacing the silicone with a safer material, and also simplifying and standardizing the surgical procedure. In particular, the danger of implant dislocation should be excluded with greater certainty. As a result, I have developed an implant made of medical-grade titanium. My surgical experiences in 20 patients with this newly developed titanium vocal fold medializing implant revealed that vocal fold medialization could be performed easily and that no perioperative complications occurred in any case. The major advantage was a significant reduction of operative time due to the preformed implant. This is not only more convenient for both the surgeon and the patient, but is also critical for obtaining optimal results due to the reduced intralaryngeal swelling and hematoma. The reduction of the glottic gap by the operation was statistically significant. Significant improvement of all voice parameters was achieved and demonstrated by a statistically significant reduction of the voice dysfunction index. Compared to the current techniques and implant systems, I see the following additional advantages: 1) titanium is a relatively safe implant material with excellent biocompatibility: 2) the design of the implant ensures optimal fixation and stabilization: 3) the implantation technique and handling is simple and time-saving; 4) the titanium sheet is easy to shape and adapt to the individual situation: and 5) only 2 sizes of implants, and no expensive instruments, are required.

Histopathology of laryngeal changes after long-term chondrosynthesis

Two patients treated for laryngeal tumors at the University of Lübeck are presented. Both underwent laryngeal reconstructions with plate and screw fixation systems immediately following partial laryngectomies. Recurrent disease was found at 14 and 55 months, respectively, and was subsequently managed by total laryngectomy. The laryngectomy specimens with the plate and screws in situ were evaluated histopathologically, paying special attention to the reaction of local tissue to the implants. Findings showed that the metallic plates were fixed with screws in the bony trabeculae of the laryngeal skeleton. The histological response showed primary wound healing without evidence of sequestration or implant loosening, as often associated with excess mechanical stress. Furthermore, there were no signs of tissue necrosis or widespread chronic inflammation. In both patients, a small discrete area of chronic inflammation and soft tissue fibrosis was noted adjacent to the screw heads. This study supports our previously documented clinical experience that the use of chondrosynthetic techniques is almost complication-free and is an ideal system for performing precise anatomical reconstruction of the laryngeal skeleton.