In this double-blinded , randomized , vehicle-controlled , prospective clinical trial , 60 consecutive consenting adults undergoing cleft lip scar revision ( CLSR ) surgery between July 2010 and March 2012 were randomized to receive botulinum toxin A ( n = 30 ) or vehicle ( normal saline ; n = 30 ) injections into the subjacent orbicularis oris muscle immediately after wound closure .