DYNAMIC BEHAVIOR OF THE PROVOX AND STAFFIERI PROSTHESES FOR VOICE REHABILITATION FOLLOWING TOTAL LARYNGECTOMY

The present study evaluated the differences in aerodynamic behavior be tween the 1990 Provox and 1986 Staffieri voice prostheses for total la ryngectomy patients. Both prostheses were submitted to in vitro labora tory testing to assess their aerodynamic behavior under different cond itions of air flow through the valve and tracheal side pressure. In ad dition, six patients using the Provox and another six using the Staffi eri prostheses were submitted to a dynamic study of phonation. This la tter study evaluated the intratracheal pressure corresponding to the d ifferent intensities at which the vowel sound /a/ was pronounced. In v itro measurements revealed significant differences between the two pro stheses, with the best results achieved with Provox. In contrast, the in vivo measurements did not reveal any significant differences betwee n the two groups of patients in the 50-79 dBSPL range, although there was some difference at intensities equal to or greater than 80 dBSPL. Again, in this latter case the best results were achieved with the Pro vox. However, the ideal prosthesis has yet to be found. In some patien ts, the so-called low-resistance prostheses fail to maintain their aer odynamic performances, most likely because anatomic resistors interfer e with the effort (i.e., pressure) required to produce a voice. At pre sent the choice of prosthesis is best determined on an individual pati ent-to-patient basis.