Detection of orbicularis oris muscle defects in first degree relatives of cleft lip children using ultrasound

The severity of cleft lip (CL) varies considerably from complete bilateral CL and palate at one end of the spectrum to a minimal CL at the other. In some cases of microform clefting, there may be no visible manifestation of the defect on the lip surface (i.e., the defect is occult) and no residual functional deficit. This study used high resolution ultrasonography to detect subclinical anomalies of orbicularis oris muscle (OOM) in first degree relatives of CL +- cleft palate children and compared it with controls.

Thirty relatives of 25 children with non-syndromic CL or CL+ CP were identified for the study. Thirty subjects having negative family history of CL/P in three generations and absence of any minimal cleft features were taken as controls. Ultrasound scans of OOM of all the controls and relatives were taken. Statistical analysis was performed using standard χ2 tests with Yates correction.

Defects were seen in 13.3% of relatives and no defects were seen in controls, this was not statistically significant.

The data support the hypothesis that subclinical CL cases with subepithelial OOM defects do exist and Orbicularis oris discontinuities represent the mildest form of CL.