An uncommon cleft subtype of unilateral cleft lip and palate.

The finding that the vomer plays a crucial role in maxillary growth suggests that the bilateral cleft configuration of unilateral cleft lip and palate (UCLP), in which the vomer is detached from the non-cleft-side secondary hard palate, negatively influences palatal development, and this hypothesis was tested. Sixty persons with complete UCLP, including those with the vomer detached from (n = 30, b-UCLP) and attached to (n = 30, u-UCLP) the secondary hard palate, were analyzed morphologically, with the use of cast models taken at 10 days, 3 mos, and 12 mos of age. The anterio-posterior palatal length at 12 mos of age in those with b-UCLP was significantly shorter than that in those with u-UCLP, by 8.7% (p < 0.05). In addition, palatal width development in the first year in those with b-UCLP was also significantly retarded. These results suggest that the uncommon bilateral cleft subtype in UCLP should be included in the cleft classification.