Dextranomeres in hyaluronan (DiHA): a promising substance in treating vocal cord insufficiency

The morphology of the rabbit vocal cord was studied after injecting a mixture of dextranomere microspheres in sodium hyaluronan solution (DiHA), two substances that are nonimmunogenic and biocompatible. DiHA is already in clinical use as a space filler in pediatric urology (Deflux R). Specimens from injected vocal cords were investigated by light microscopy at different time intervals up to 6 months after injection. On macroscopic examination a bulge was seen in the injected vocal cord, and on microscopic examination new fibrous connective tissue developed. Throughout the study a weak inflammatory reaction was observed, but no foreign body reaction. Hyaluronan disappeared from the injected site within 1 week, but the dextranomeres remained and were recovered intact up to 6 months after injection. The dextranomeres recruited fibroblasts that generated new collagen, resulting in endogenous soft tissue augmentation. It is conceivable that DiHA may become a useful injection material for treatment of vocal cord insufficiency.