Premaxillary protrusion assessment by the maxilla-nasion-mandible angle in fetuses with facial clefts.

OBJECTIVE

The aim of the study was to measure the degree of premaxillary protrusion in fetuses with orofacial clefts of various severities.

METHODS

The maxilla-nasion-mandible (MNM) angle was measured retrospectively on by multiplanar corrected volumes. Sixty-two fetuses with orofacial clefts and known outcome volumes of the fetal head were available.

RESULTS

In 48 of the 62 cases, the MNM angle could be measured [mean gestational age 23 (range, 18-30) weeks]. The mean MNM angle was normal in all nine cases with cleft lip and intact alveolar ridge (15.2°; range, 12.5°- 16.9°). In 24 cases with unilateral cleft lip with or without cleft palate (UCL/P), the mean MNM angle was 20.0° (range, 13.3-26.2°), being above the 95th percentile in 79% (n = 19) and normal in 21% (n = 5). In 14 bilateral cleft lip and palate (BCL/P) cases, the mean MNM angle was 26.5° (range, 19.2°-33.7°) and above the 95th percentile in all cases. There was no difference in MNM angle between isolated clefts and clefts associated with other anomalies. In one case with a Tessier 4 cleft, the MNM angle was above the 95th percentile (25.2°).

CONCLUSION

The premaxilla tends to protrude in both BCL/P as UCL/P cases. The degree of protrusion varies greatly, especially in the BCL/P group.