Influence of endoscopic sinus surgery on voice quality.

Twenty-one patients with documented chronic paranasal sinusitis and in need of endoscopic endonasal sinus surgery were subjected to voice analysis. Tape recordings of different sustained vowels were performed pre- and postoperatively. All voice samples were examined with a sound spectrographic analysis system. Patients having known nasal obstruction detected by active anterior rhinomanometry were excluded from further study. Analysis of pre- and postoperative spectrograms focused on changes in center frequency or bandwidth of the first four formants, as well as variations in specific differences of the formant frequencies and amplitudes. The different subgroups of patients revealed a series of significant changes in the parameters studied. The vowels [a:] and [i:] showed inverse changes in measured values, while evaluation of the vowel [u:] was restricted due to artifactual scattering of individual values. In general, band-width diminished and energy peaks of formants increased postoperatively. In 6 of 21 patients (approximately one-third of the cases), patients or other individuals detected perceptual changes of speech postoperatively. Based on our data, we recommend informing all patients, and voice professionals in particular, about the possible effects of endonasal sinus surgery on altering speech.