A novel method of tracheal anastomosis healing using a single submucosal injection of basic fibroblast growth factor: initial report

OBJECTIVES: For the technical management of tracheal anastomosis, developing new and simple methods is required to relieve anastomotic tension. This study aimed to investigate whether basic fibroblast growth factor (bFGF) only once injected immediately before anastomosis promotes cartilage regeneration at the tracheal anastomosis and whether the regenerated cartilage has the effect of reinforcing the anastomosis in a rabbit model. METHODS: New Zealand white rabbits were anaesthetized, and the cervical trachea was exposed through a cervical midline incision, followed by resection of the 10th tracheal cartilage. The rabbits were categorized into 2 groups: the bFGF group (n = 6) and the control group (n = 6). In the former group, bFGF (25 μg) was administered into the submucosal layer of the cartilage using a 27-G needle immediately before tracheal anastomosis. The animals were sacrificed 4 weeks later. Histological, mechanical and biochemical evaluations were performed on this anastomosed trachea. RESULTS: At 4 weeks of age, the anastomoses were spindle-shaped and displayed maximum diameter at the injection site compared with those in the control group. Histological evaluation showed that cartilage tissue had regenerated between the 9th and 11th tracheal cartilage rings. Tensile test showed that the anastomoses displayed a significantly high strain/stress ratio (P = 0.035). The collagen type II and glycosaminoglycan levels were significantly increased, and the collagen type I level was significantly decreased (P = 0.019, P = 0.013 and P = 0.045, respectively). CONCLUSIONS: A new wound-healing concept of airway anastomosis could be provided by the results that single injection of bFGF regenerated tracheal cartilage in rabbits and strengthened the anastomosis by bridging the regenerated and well-matured cartilage. Further investigation of this method will lead to potential clinical applications for reinforcement of tracheal anastomoses.