Abstract
Studies of the influence of surgery on facial growth in cleft lip and palate must take into account inherent variations in craniofacial form independent of surgery. Primary surgery, the most important iatrogenic influence on facial form, can differ in technique, timing, and sequence, and one of the major challenges in researching the topic is the remarkably varied clinical protocols in current use. Unfortunately, systematic attempts to compare dentofacial outcomes reported in the literature are unlikely to be reliable, as methodologic biases cannot be overcome. Rigorous intercenter studies can improve the dependability of data and provide evidence of the success of cleft services as a whole, but they are still subject to biases introduced by differences in surgical skills and underlying craniofacial form. These shortcomings are finally being overcome through multicenter randomized control trials.