Thickness of Orbicularis Oris Muscle in Unilateral Cleft Lip

Abstract

Our protocol for closure of unilateral complete or severe incomplete cleft lip begins with active dentofacial orthopedics (Latham device) followed by nasolabial adhesion and alveolar gingivoperioplasty. We have observed that preliminary adhesion provides more orbicularis oris muscle for the second-stage labial repair. A quantitative prospective assessment of all patients undergoing nasolabial adhesion by the senior author between November of 2009 and July of 2010 was undertaken to assess whether there is an increase in lateral orbicularis oris muscle mass by the time of formal repair. Standard anthropometric points were placed before nasolabial adhesion and again at the second-stage closure. Ultrasonographic measurements of orbicularis muscle thickness were made on both lateral labial elements along a line drawn between sbal and cphi. The mean interval increase in thickness of lateral orbicularis oris was determined. Sixteen patients underwent nasolabial adhesion during the study period. Four patients with asymmetric bilateral cleft lip patients and 2 patients who did not have a second ultrasonographic study were excluded. The remaining 10 patients in the study had a nasolabial adhesion at a mean age of 3.9 months (range, 3.1-4.3 months). Mean orbicularis oris thickness before adhesion was 0.7 mm on the cleft side and 1.2 mm on the noncleft side. The increase in orbicularis thickness after the mean interoperative interval of 2.9 months (range, 2.6-3.5 months) was calculated. On the cleft side, there was 0.8 mm (138%) mean increase in orbicularis oris muscle thickness compared with 0.4 mm (32%) mean increase on the noncleft side. Labial adhesion in preparation for repair of unilateral complete or severe incomplete cleft lip results in a measurable increased thickness of lateral orbicularis oris. This additional muscular bulk is useful in construction of the philtral ridge.