Introduction: Congenital scoliosis and fused ribs can create athree-dimensional deformity affecting the normal thoracic growth and function resulting in thoracic insufficiency syndrome. The objective of this study was to develop an animal model to evaluate the effect of chest deformity on pre- and post-natal lung development and volume. There is currently no animal model of chest wall deformity mimicking the thoracic insufficiency syndrome seen in humans available to study the impact of an expansion thoracoplasty.
Method: Fetal surgery was performed in 8 ewes between 65 and 70 days gestation (term:140d) under anesthesia. Following exposure through a hysterotomy, a left thoracic deformity was created in 9 fetal lambs by either tying 3 ribs together or adding resection of the 7th rib in addition to partial destruction of the vertebral body.
Results: All 9 lambs who underwent surgery were born at term through vaginal delivery and suffered from a scoliotic and thoracic deformity ranging from mild to severe (Cobb 10 – 70). They were all sacrificed at 2 months of age for necropsy except for one animal who died earlier from failure to thrive. The scoliotic and chest wall deformities were maintained during the post-natal period.
Conclusion: We have successfully created a model of congenital thoracic deformity that can be used to study the impact of the deformity on lung development and to evaluate treatment strategies. This novel approach is attractive because it could theoretically recreate a form of congenital scoliosis/thoracic insufficiency syndrome seen clinically very early in life.
Significance: Congenital human chest wall deformity represents a disease continuum that starts early during fetal life and progresses thereafter. Therefore, the detrimental impact of the thoracic deformity on lung development is established prior to birth. This animal model will allow the evaluation of thoracic growth modulation, the evaluation of lung development during normal growth and in the presence of a prenatal chest wall deformity, as well as the evaluation of the impact of different treatment strategies on the deformity as well as lung development.