It has been recently noted that laryngeal paralysis results in a complex alteration of the glottis. The membranous segment of the paralyzed vocal fold is shortened, and, during phonation, patients use hyperfunction to shorten the normal vocal fold to about the same length. Additionally, if the paralyzed vocal fold is not near the midline, the angle between the membranous and cartilaginous segments of the vocal fold is decreased, resulting in a "posterior" gap which cannot be closed by hyperadduction of the normal side. To determine whether arytenoid adduction addresses these problems, videolaryngoscopy was analyzed in 11 patients before and after surgery, and results were compared to patient satisfaction and acoustic and aerodynamic assessment. The posterior gap and glottic competence were improved in all patients, but only 6 had improvement in symptoms. Two had persistent vocal fold bowing but achieved good function after Teflon injection. Three patients, all with paralysis for more than 20 years, had no increase in vocal fold length and very little subjective vocal improvement. Arytenoid adduction is most effective in acute cases. Poor functional results in chronic paralysis are related to failure to achieve vocal fold lengthening, presumably due to soft-tissue contracture.