[Comparative study of cartilaginous and synthetic laryngotracheoplasty. An experimental study in rabbits]

The most significant advance in the treatment of laryngotracheal stenosis in children is the augmentative laryngotracheoplasty using a graft of autologous rib cartilage (ARC). In order to reduce the potential morbidity of this technique due to the additional surgical procedure, the use of a ceramic, hydroxyapatite (HA), implant was compared to ARC in a randomized experimental study in 99 New Zealand rabbits: 32 rabbits had ARC grafts, 33 had HA implants covered with a graft of perichondrium (HAP) and 33 had naked HA implants. At 3 months, immediately before necropsy, there was no significant clinical difference between the 3 groups of animals. Histological examination was performed in 81 animals. Implants were found in 54 specimens. More implants were found in the ARC group than in the HA groups (p < 0.003). No difference was noted between the 3 groups in the epithelial covering of the implant, the amount of inflammation, the analysis of the interface between the implant and the cricoid cartilage and in the viability of the graft. No implant was found in 27 animals. However, scar bands of approximately the same width as the implant were responsible for cricoid diastasis in 23 cases. Therefore, it seems that the missing implant played the role of spacer. While this experimental study does not eliminate HA as a augmentative implant in the subglottic region of the rabbit, the evolution of the scar bans must be followed for a longer period in rabbits before considering the clinical application of this technique.