Total laryngectomy is a surgical treatment for extensive cancer of the larynx or hypopharynx, which alters speech, swallowing, and respiration. During the last two decades, surgical voice restoration procedures comprising tracheo-esophageal puncture techniques with insertion of a so-called "voice prosthesis" have greatly improved successful voice acquisition following laryngectomy (see Chapter 1 for a literature survey). Most voice prostheses are made of silicone rubber because of its excellent mechanical and molding properties. However, the major drawback is engendered by concurrent microbial colonization of the devices. Clinically, voice prostheses have to be replaced when, due to biofilm formation, patients complain about leakage of food and liquid or increased air flow resistance.
Infection and deterioration of implanted polymeric medical devices is a major problem in
medicine. Since microbial adhesion to implanted devices is determined by its surface properties, prevention of biofilm formation could involve the modification of the surface properties of the voice prosthesis. As silicone rubber is known to be hydrophobic, we first attempted to hydrophilize the silicone rubber surface in order to enhance its anti-fouling properties. RF plasma treatment is often a useful method to hydrophilize polymer surfaces, but effects of a single plasma treatment of silicone rubber are usually transient due to the high mobility of its siloxane backbone. Therefore, in Chapter 2 and 3, solutions has been proposed to overcome this problem so-called hydrophobic recovery.