Injection laryngoplasty (also known as vocal fold injection) is a medical procedure used to treat a voice box (larynx) where one of the vocal cords is weak, paralyzed, or atrophied.

In simple terms, a "filler" material is injected into the affected vocal cord to "bulk it up." This moves the paralyzed cord closer to the middle, allowing the healthy cord to meet it properly. When the cords can touch again, it restores the ability to speak clearly and swallow safely.