Object: Patients submitted to surgical advancement of the upper and middle facial third might have a relapse of the skeletal retraction after the removal of the distractor devices. Clinical signs related to this process are usually represented by exophthalmos, Obstructive sleep apnea syndrome (OSAS) or prognathism; however, the analytic definition of the relapse is very difficult , conventional cephalometric methods being influenced by the spatial movement of "N" (nasion) or "Or" (orbital) points. The authors present a new cephalometric technique that could be used as a more objective mean of follow-up evaluation of patients undergoing craniofacial advancement.
Materials and methods: The cephalometric analysis proposed is based on angles, lines, areas and distances between BaS (Basion-Sella) axis and other craniofacial landmark points. We have defined this cephalometric technique as "BaS Analysis".
Conclusion: The "BaS analysis" is not influenced by splanchnocranium movements in the space; for this reason, it can be considered a useful method for cephalometric analysis in the follow-up of patients with craniofacial malformations.