Injectable cross-linked bovine collagen has been shown to be effective in the management of glottic insufficiency. Previous studies have demonstrated that collagen injection is uniquely helpful in the management of atrophic vocal folds, minimal glottic insufficiency, scarred vocal folds, and focal defects or adynamic vocal fold segments. With the proliferation of new treatment options for glottic insufficiency, it seemed appropriate to target a specific population who were not ideal candidates for other forms of treatment. Since collagen injection had been shown safe and effective for vocal fold augmentation and yet remained an off-label application, this National Center for Voice and Speech study was conducted at the University of Wisconsin Clinical Science Center under an investigator device exemption and supported largely by the Federal Drug Administration Orphaned Product Division.
The primary aim of this project was to assess a treatment option for patients with glottic insufficiency for whom other forms of treatment were considered inadequate or contraindicated. Unlike earlier collagen injection studies, we excluded patients who were suitable candidates for other forms of treatment. The study was designed to allow rigorous voice assessment so that efficacy or failure of treatment could be objectively documented. A related question to be addressed was the relative efficacy of collagen in the treatment of several different vocal fold pathologic conditions. Although safety of collagen injection has be previously reported another aim of this study was to further document the safe use of this implant material in the human larynx.