"Pre and Post Treatment Comparison of S/Z Ratio in Benign Laryngeal Lesions".

Abstract

Benign laryngeal lesions like vocal nodules, vocal polyp, vocal fold cysts are mostly found in patients complaining of change in voice. S/Z ratio has become the most frequently used clinical tool to assess phonatory mechanics. This study shows the pre-treatment and post-treatment comparison of S/Z ratios in patients with benign laryngeal lesions. To evaluate the outcome of microlaryngeal surgery in patients with benign laryngeal lesions using S/Z ratio as an outcome parameter. During this study, 65 patients with complaints of change in voice, with clinical evidence of benign laryngeal lesions underwent microlaryngeal surgery. Improvement in symptoms were measured preoperatively and postoperatively using S/Z ratio. This ratio was calculated by asking the patient to to maximally sustain 'S' and 'Z', repeated thrice. S/Z ratio was calculated by dividing the maximum duration for which /S/ was sustained by the maximum duration for which /Z/ was sustained. A ratio of more than 1.4 suggested a vocal cord disorder. There was statistically significant difference observed in S/Z ratio values, from pre-treatment to 6months post-treatment, with P value 0.001. Pre and post treatment assessment of patients with benign vocal fold lesions showed significant improvement in S/Z ratio postoperatively. It is the simplest and a reliable objective method of voice assessment and can also be used in assessing the outcome of the treatment.