Methods: Twenty-four New Zealand rabbits were divided into four groups, each of which included six rabbits. The third and fourth costal cartilages in both hemithoraces were excised totally in all groups. The perichondrial beds were closed at both hemithoraces, but reshaped cartilages were implanted into the left hemithorax. Group 1 and group 2 were selected as control groups. After surgery, groups 3 and 4 received hyperbaric oxygen treatment of 2.5 ATA pressure once a day for one week. The rabbits in groups 1 and 3 were sacrificed at the fourth week and in groups 2 and 4 at the eighth week after the operation. A numerical scoring scheme modified from histological evaluations of fracture healing was used to assess the neochondrogenesis and scar tissue formation. Histopathological scoring was made according to the amount of fibrous tissue and cartilage in perichondrial bed for each specimen.

Results: According to the numerical scoring scheme, the score of left perichondrial bed was significantly higher for group 4, compared to the other groups (p=0.027). However, it was not significant in the right perichondrial bed (p=0.063). The differences in the diameter of the newly developed cartilage was not significant among the groups (p>0.05).

Conclusion: Our study indicated that receiving postoperative hyperbaric oxygen treatment increased the chondrogenesis in the perichondrial bed in rabbits, which is very important to obtain a flexible and stable chest wall after the correction of pectus deformities.