Problem: Various methods have been studied to improve tracheal healing after surgery. Previous experiments have demonstrated the benefits of hyaluronic acid (HA) not only in wound healing in the tympanic membrane, skin, and articular cartilage but also in decreasing adhesions in abdominal operations. The goal of this project was to study the effects of hyaluronic acid on tracheal wound healing.

Methods: Twenty-two New Zealand white rabbits, (11 experimental, 11 control) had a 2 mm round defect created in the third tracheal ring. The experimental group had an 8 mm round sodium hyaluronate-based sponge (SEPRAPACK^TM) fixed over the defect using fibrin glue (Hemaseel^TM). The control group had a plain 8 mm collagen sponge placed in a similar manner. Tracheal tissue was harvested at 4 weeks postop and histologically scored in regard to inflammation, connective tissue organization, epithelial closure, chondrocyte death, and cartilage regeneration (clonal cell formation) at the area of injury. Statistical analysis was done using the Mann-Whitney U and Fisher-Exact tests.

Results: Inflammatory cell infiltration was significantly increased at the area of injury in the control group compared to the HA-treated wound (P = 0.014). In the HA-treated group a lower percentage of animals had chondrocyte death at the wound edge (45.5%−HA vs 81.8%−control) (P = 0.183) and a greater percentage of animals demonstrated new clonal cell formation (72.7%−HA vs 54.5%−control) (P = 0.659). No differences were seen in connective tissue organization and epithelial closure.

Conclusion: These results show that HA significantly decreases inflammation in tracheal wounds in a rabbit model. Although not statistically significant, the results also suggest that HA may be chondroprotective, as demonstrated in articular cartilage models.

Significance: Poor wound healing including cartilage ring damage can contribute to airway compromise especially in an infant after tracheal surgery. This experiment suggests that HA may be useful as an adjunct in improving postoperative tracheal repair.

Support: (1) The Friedberg Research Fund in the Department of Otolaryngology at Rush University Medical Center. (2) SEPRAPACK^TM and Hemaseel ^TM were both donated by GYRUS ENT and HAEMACURE, respectively under no obligation by the authors.