AERODYNAMIC CHARACTERISTICS OF THE NIJDAM VOICE PROSTHESIS IN RELATION TO TRACHEOESOPHAGEAL WALL THICKNESS

Tracheo-esophageal speech using various pros theses is currently the m ost successful form of voice and speech rehabilitation for laryngectom ees. Main inter-device differences are durability and trans-device pre ssure loss during speech. The valveless indwelling Nijdam voice prosth esis is a new voice prosthesis. A barrier mechanism is created by a co mbination of the esophageal mucosa and the umbrella-like ''hat'' of th e prosthesis that covers the esophageal side of the tracheo-esophageal fistula. The Nijdam prosthesis can be used clinically for longer peri ods of time when compared to such other indwelling voice prostheses as the Provox prosthesis and the low-resistance Groningen prosthesis. Ho wever, trans-device pressure loss during speech has been unknown. Adju stment of the shaft length of the Nijdam voice prosthesis to tracheo-e sophageal wall thickness was expected to affect trans-device pressure loss during speech. We report the results of in vitro tests to quantif y the effect of tracheo-esophageal wall thickness on trans-device pres sure loss. In the present study pressure loss was measured at differen t air flow rates in relation to tracheo-esophageal wall thickness. Fin dings demonstrated that when shaft length of the Nijdam prosthesis cor responded exactly to tracheo-esophageal wall thickness, trans-device p ressure loss was comparable to that of the Provox prosthesis. If a rel atively shorter Nijdam prosthesis was chosen to prevent aspiration fro m occurring, the pressure loss across the prosthesis increased to that of the low-resistance Groningen prosthesis.