Exorbitism correction of faciocraniosynostoses by monobloc frontofacial advancement with distraction osteogenesis

Monobloc frontofacial advancement with internal distraction osteogenesis is still a relatively new technique, and the literature on exorbitism correction of syndromal faciocraniosynostosis with monobloc advancement is scarce. Using a image processing software, we measured on axial computed tomographic scans the effect of monobloc advancement on the correction of exorbitism on a large series of patients (n=38) with syndromal faciocraniosynostosis who underwent surgery for correction of cranial and facial hypoplasia. A population reference of 23 patients without faciocraniosynostoses was also measured. For each orbit, globe protrusion was expressed as the ratio between the length of the globe that is above the interzygomatic line and eye size. The results indicate that monobloc has a symmetrical effect on both eyes that is correlated to the preoperative degree of exorbitism. Longitudinal data indicate that exorbitism correction changes with time. A mean preoperative globe protrusion of 0.86 dropped sharply to 0.54 at 6 months after distraction and increased to 0.61 at 16 months after distraction removal, a value that is not significantly different from the ratio of the control group (0.60). Overall, the data suggest that a certain degree of enophthalmos in the early postoperative period does not necessarily imply a sustained overcorrection.