Does surgical sequencing influence the accuracy of maxillary positioning in bimaxillary cleft orthognathic surgery?

PURPOSE: To evaluate whether the sequence of osteotomies influences the accuracy of maxillary positioning in patients with cleft palate ± cleft lip undergoing bimaxillary orthognathic surgery (OGS). METHODS: This was a prospective study of patients with Veau 2-4 clefts who underwent bimaxillary OGS at tertiary-care children’s hospital over a 3-year period. The primary predictor variable was the sequence of osteotomies (maxilla-first versus mandible-first). The primary outcome of interest was the concordance between the planned and achieved maxillary position, as assessed using linear and angular measurements. Secondary study predictors were demographic and surgical variables. Differences between groups were compared using non-parametric independent samples tests for continuous measures (data reported as median and interquartile range, IQR) and chi-squared tests for categorical measures. For all analyses, p≤ 0.05 was considered significant. RESULTS: Subjects who underwent maxilla-first (n=15) and mandible-first (n=16) operations were comparable with regard to age, gender, cleft type, skeletal classification, segmental maxillary osteotomy, and magnitude of maxillary movement (p ≥ 0.09). The planned sagittal and vertical positions of the maxilla were similarly accurate between the two groups (p ≥ 0.68). Angular accuracy was also comparable (p ≥ 0.56) between the study groups. CONCLUSION: In patients with CP ± CL undergoing bimaxillary orthognathic surgery, use of mandible-first sequencing, when compared to maxilla-first sequencing, does not impact accuracy of maxillary positioning in the immediate post-operative period in well-selected patients.