Vocal fold healing after laser cordectomy with adjuvant cryotherapy.

Objectives: To understand the effect of adjuvant cryotherapy on glottic wound healing after endoscopic CO2 laser cordectomy.

Study Design: Canine acute injury model with videolaryngostroboscopic and histopathologic outcomes analysis.

Methods: Twelve adult male dogs underwent bilateral endoscopic CO2 laser transmuscular cordectomy followed by randomized unilateral endoscopic glottic cryotherapy. The animals were randomly divided into four groups and underwent videolaryngostroboscopy followed by sacrifice at 0, 2, 6, and 12 weeks postoperatively. Three untreated male dogs served as controls. Histopathologic sections were prepared with Alcian blue, Giemsa, hematoxylin-eosin, movat's, Masson's trichrome, and picrosirius stains.

Results: Videostroboscopy demonstrated an earlier restoration of glottic volume and a return of mucosal waves among vocal folds treated with combined therapy by 6 weeks posttreatment. The mean depth of inflammatory reaction in the vocal cords treated with combined therapy was 1.07 mm versus 1.15 mm in vocal cords treated with CO2 laser therapy alone. At 2 and 6 weeks postoperatively, combined treatment was associated with a decreased volume of collagen. At 12 weeks postoperatively, combined treatment was associated with greater collagen organization, normalized collagen histoarchitecture, and decreased keratinization.

Conclusions: Adjuvant cryotherapy appears to alter glottis-specific wound healing, leading to decreased and more organized collagen formation and decreased keratinization with a resultant improvement in glottic function, when compared with CO2 laser surgery alone, in an acute canine injury model. Studies in humans are ongoing to further evaluate the clinical potential of cryotherapy on glottic wound healing.