The average cross-sectional area statistics from the Avizo Fire quantification. The volume was normalized to the trachea length (volume divided by length). The sample sizes in each group and time point were the following: Scaffold-only 6 week (n=3), Scaffold-only 12 week (n=4), Scaffold-only AE (n=2); TGF-β3 6 week (n=3), TGF-β3 12 week (n=3), TGF-β3 AE (n=3); BMSC 6 week (n=4), BMSC 12 week (n=5), BMSC AE (n=1). The BMSC group was the only group to have significantly smaller average cross-sectional area than the native tracheas, aside from the AE (# significantly larger average cross-sectional area when compared to the AE in the same group [p<0.05], @ significantly larger average cross-sectional area when compared to the BMSC-group at week 12 [p<0.05], * significantly smaller average cross-sectional area when compared to the native tracheas [p<0.05]).