STELLAN HERTEGARD, MD, PHD; LIISA D'AGATA AKE DAHLQVIST, MD; CLAUDE LAURENT, MD, PHD; ELISABETH SEDERHOLM, SLP; LARS HALLEN, MD; PER TESTAD, MSC
HUDDINGE, SWEDEN

Glottal insufficiency may result from unilateral vocal fold paresis, atrophy, or scar defects of the vocal folds. The voice is often weak or aphonic with severe speech problems. Materials such as Teflon, silicone, or collagen have been used as augmentation substances in order to increase the vocal fold mass and improve glottal closure. Problems with inflammation, migration, or resorption have limited the success of treatment. Therefore, new natively derived injection materials have been studied. In a prospective study, 83 patients with glottal insufficiency were included (mean age, 66 years; range, 22 to 90 years). We report results from 64 patients (45 men and 19 women) who were randomized for injection treatment with Hylan B gel, a cross-linked hyaluronan, or bovine collagen into one vocal fold. Most injections (64°l0) were given under local anesthesia. Videostroboscopic larynx recordings, subjective symptom ratings (VAS scales), and digital audio voice recordings were obtained before and 6 and 12 months after treatment. Computerized measurements of vocal fold parameters were made from digitized videostroboscopic larynx recordings. The Soundwell program was used for analysis of the fundamental frequency, perturbation, and long-time average spectrum. Nonparametric statistical methods were used to analyze the data (Wilcoxon rank sign test, Mann-Whitney). At 6 months' follow-up, the patients reported improved voice according to the VAS scales for both collagen and Hylan B gel. The vocal fold measurements showed a significant decrease in minimum glottal area (improved glottal closure) and improved glottal vibrations for the Hylan B gel. The acoustic analysis showed significantly decreased perturbation and increased level of the first formant for the Hylan B gel. The results for the collagen group did not show any significant changes. Measurements at the vocal fold medial edge indicated a significantly smaller degree of resorption for Hylan B gel patients than for the collagen group. Three patients out of all 83 in the study had a temporary inflammation in the injected vocal fold (all after Hylan B gel injections). However, it resolved with conservative medical treatment within I month. The results from 12 months will be reported. Both Hylan B gel and collagen can be relatively safely used for injection treatment of glottal insufficiency. The analysis of videostroboscopy and acoustic voice analysis showed significant improvement for the patients treated with the Hylan B gel as compared to collagen.