Effect of lip closure on facial growth in the surgically induced cleft rabbit.

This project was designed to determine whether cleft lip repair has an influence on facial growth. To study this, 62 rabbits were divided into four groups: control, control without repair, Millard-type repair, and Bardach-type repair. Surgical clefts of the lip, alveolus, and the palate were created in 6-week-old rabbits. Periodic measurements were made of the pressure exerted by the lip on the maxillary alveolus. The animals were killed 20 weeks postoperatively. The skulls were processed and measurements were taken from the skulls. The pressure measurements showed a definite increase in lip pressure on the maxillary alveolus for the lip repair group. This pressure was high soon after surgery, rapidly returned toward the control level, but never reached it. Skull measurements indicate an inhibition in anterior maxillary growth for the “control without repair” group. This inhibition was even more profound in the two lip repair groups. No significant differences were found in maxillary width or mandibular length. When correlations were made to see if increased lip pressure resulted in decreased anterior maxillary growth, a significant correlation was found for both lip repair groups. This means that as the pressure of the lip repair increased, it resulted in a decrease in anterior maxillary growth. The data reported here indicates that cleft lip surgery must be considered as having a definite influence on anterior maxillary growth inhibition observed in the cleft lip and palate population. Further studies are indicated to determine the role of cleft palate repair on facial growth.