Effect of Preoperative inhibition of Orbicularis Oris Muscle action On Philtrum length in primary Cleft Lip Repair

Hypothesis: Botulinum toxin injection before cleft lip repair will inhibit the Orbicularis Oris muscle action and decrease the tension applied on the wound edges during healing leading to improved esthetic outcome.
Methods: Thirty two patients, under 6 months of age, with complete unilateral cleft lip, were enrolled in this double-blind, randomized, placebo-controlled prospective study. Patients were randomly divided into two equal groups; in the BTX group, botulinum toxin type A (BTX-A) was injected while in the Placebo group normal saline was injected in 4 points in the subjacent orbicularis oris muscle on both edges of the cleft, one week before the primary lip repair. At six-month follow up patients were assessed, in blinded fashion, for length of philtrum ridge both in cleft and non-cleft sides as well as for scar width. Collected data were tabulated and statistically analyzed.
Results: Thirty patients completed the study. After 6 months, difference in philtrum length between cleft and non-cleft sides in the BTX group was significantly less than the placebo group (P=0.001). The scar width in the BTX group was also statistically significantly less than the Placebo group (P =0.001).
Conclusions: Inhibition of orbicularis oris muscle during wound healing by BTX injection, before primary repair of unilateral cleft lip, safely and effectively reduced the difference in philtrum length between cleft and non-cleft sides and it also reduced the width of the scar.