Comparison of nasopharyngeal growth between patients with clefts and noncleft controls

This study was a comparison of the cephalometric growth characteristics of the nasopharyngeal structures between UCLP and noncleft controls.

Eighty patients with complete unilateral cleft lip and palate (UCLP group) and 82 noncleft controls (NCC group) were assigned to four developmental stages (i.e., stage 1, at 4 years; stage 2, at 8 years; stage 3, at 12 years; and stage 4, at 17 years of age). Measurements on the anteroposterior and the vertical dimensions were derived from reference lines and points of nasopharyngeal structures on the lateral cephalograms.

The results showed that there were no growth differences between the two groups at any stages in the regions of cranial base and cervical vertebrae, and that growth of the posterior maxilla in the UCLP group was significantly less at any stage in both A-P and vertical dimensions than in the NCC groups. As well, the nasopharyngeal triangle (Ho-At-PMP) in the groups showed almost parallel increase with stage, though with short vertical dimension in the UCLP group, and the soft palate length in the UCLP group was significantly less at stages 2, 3, and 4 compared to that in the NCC group. The adequate ratio (soft palate length/pharyngeal depth) in the UCLP group tended to decrease and was significantly less at stage 4 compared to that in the NCC group.

These results indicate that the growth of the cranial base and the upper cervical vertebrae is independent of the effect of clefts or of surgeries on clefts, and that the growth inhibition at the posterior maxilla results in morphologic disharmony of upper nasopharyngeal structures. This could be a potential factor for the reappearance of velopharyngeal incompetence at a later age.