Choi N, et al. - Given additional injection laryngoplasty (IL) will be one of the next choices to treat cases of insufficient voice improvement following IL, but there is inadequate knowledge regarding the voice outcomes concerning an additional IL, so, researchers undertook this retrospective comparative study in a single institution in order to gain insight into this topic. Participants were patients having unilateral vocal fold paralysis, who took IL (N = 76) twice due to insufficient voice improvement. Following both the first and second rounds of IL, a significant improvement was evident in aspiration, maximum phonation time, jitter percentage, shimmer percentage, and noise to harmonic ratio. Following both the first and second rounds of IL, a significant improvement was also noted in the voice handicap index–30. Findings revealed that further improvement of voice in patients who experienced unsatisfactory voice outcomes despite initial IL could be achieved with additional IL, in selected patients.