Complications of injection laryngoplasty using calcium hydroxylapatite

Objective: To report the adverse effects of using calcium hydroxylapatite (CaHA) paste as a vocal fold filler.

Methods: Approval of this study was obtained through the institutional review board at Drexel University College of Medicine. Sixteen patients had 22 vocal fold injections with CaHA paste to treat glottic insufficiency. The initial procedures were performed at three different institutions between January 2006 and August 2009. Diagnosis and treatment of the complications in all cases were performed at our institution. Pre- and postinjection mucosal waves were assessed using strobovideolaryngoscopy when possible. All stroboscopic examinations were reviewed independently. Decreases in amplitude and waveform were classified as mild, moderate, or severe. Implant location was examined using computed tomography (CT) scan with 1-mm cuts through the larynx in patients suspected of having implant malposition. Vocal fold function was compared before and after injection, as well as after implant removal in selected cases. Histological section of explanted material was obtained. Major and minor complications were noted in 19 vocal folds.

Results: Ten major complications were encountered after surgery at three institutions. These included four vocal folds with adynamic mucosa, six with a severely decreased wave, and two granulomas affecting the vibratory margin. CT scanning confirmed six cases of implant malposition (possibly migration). Six implants were removed through endoscopic lateral cordotomy between 2 and 24 months after injection. Mucosal wave function recovered in five vocal folds after explantation. Minor complications were encountered in nine additional vocal folds. These included tissue inflammation marked by edema, erythema, and mild-to-moderate mucosal wave restriction and hypervascularity.

Conclusion: Injection laryngoplasty using CaHA paste has been regarded as an effective treatment for glottic insufficiency. In some patients, CaHA can cause an intense inflammatory reaction, potentially migrate, and compromise vocal fold function. It should be used with full understanding of the potential serious adverse reactions and risk of at least minor impairment of vibratory function.