Mandible, tongue, and airway in Pierre Robin sequence: a longitudinal cephalometric study.

The purpose of this retrospective longitudinal cephalometric study was to analyze size, growth, and relations of the mandible, tongue, and airway in the isolated, nonsyndromic Pierre Robin Sequence (PRS) infant. The objective was to understand better the early morphologic changes that occur in these structures. The data were obtained from lateral cephalometric radiographs taken in the first 2 years of life on 17 PRS infants, 26 isolated cleft palate (CP), and 26 normal control (N) infants. Mean values of each variable were compared using a univariate analysis of variance. A multivariate discriminant function analysis (DFA) was also used to characterize group differences. The three groups were distinct throughout the period of study. Differences were greater at the earliest age and the distinction was greater between the PRS and N infants with the CP infant in between, but having more similarity to the PRS infant. Initially, the PRS infant had a shorter tongue and mandibular length, narrower airway, smaller tongue area and the hyoid position was more posterior and inferior as compared to N. The tongue shape and position were specific to the PRS infants. This group distinction diminished with age and resulted from an increased mandibular growth rate in the PRS infant. These findings support the hypothesis of "partial mandibular catch-up growth" in the PRS infant. The increased growth rate in the PRS infant improved the airway dimension, which might be partly responsible for the natural resolution of the respiratory distress. This increased growth rate did not allow for the various structures to reach values equal to normal.