Factors that affect variability in impairment of maxillary growth in patients with cleft lip and palate treated using the same surgical protocol.

No consensus exists about the causes of restriction of maxillary growth in patients with cleft lip and palate (CLP). The aim of this study was to try to identify causes of this impairment other than the influence of surgical technique and skill. We analysed a sample of 129 consecutively treated 5-year-old children with unilateral cleft lip and palate (UCLP), who were operated on by the same surgeon with the same protocol. Multiple cephalometric measurements of the sample showed a wide distribution of values for maxillary growth. We selected SNA as a value describing maxillary position. Variables investigated were: initial cast measurements; timing of lip and of gingivoalveoloplasty (GAP)/palatal surgery; and presence of permanent lateral incisors. The significance of differences was investigated with Pearson's correlation and analysis of variance (ANOVA). The factor most significantly linked with maxillary protrusion was the presence or absence of the permanent lateral incisor, even when peg laterals and supernumerary laterals were considered. Initial width of the palate measured on infant casts correlated with maxillary growth, but the timing of GAP did not. Although surgical skill and technique may be the most important factors responsible for impairment of maxillary growth, inherent tissue hypoplasia, possibly the lack of lateral incisors, seems to be the most important non-iatrogenic factor.