Bone Resection Versus Setback in Reduction Malarplasty: A Quantitative Analysis of the Migration of the Summit of the Zygoma

We hypothesized that the amount of bone resection and setback together controls the effect of reducing the zygomatic body during reduction malarplasty; however, quantitative analyses of this movement are lacking.

A retrospective study of patients who underwent reduction malarplasty between Aug. 2013 and Jan. 2015 was performed. We used 3-dimensional computed tomography (3D CT) scanning to measure movements of the summit of the zygoma (SOZ). We analyzed 394 zygomas in 197 patients.

The bone resection amount was not significantly correlated with the anteroposterior movement of the SOZ (p = 0.270); in contrast, the setback amount, was significantly correlated with anteroposterior SOZ movement (p < 0.001). The bone resection amount was not correlated with cephalocaudal movement (p = 0.158); however, cephalocaudal movement was significantly correlated with the setback amount (p < 0.001). Both the bone resection amount and the setback amount were correlated with mediolateral movement (p < 0.001). The amount of bone resection determined the mediolateral movement. Both the bone resection amount and the setback amount were correlated with the mean movement distance of the SOZ (p < 0.001). Both the R ² (0.704 > 0.084) and β (0.839 > 0.290) values indicated that the setback amount made a larger contribution to the SOZ movement distance than did the bone resection amount.

Whereas bone resection was the major factor in the medial movement of the SOZ, bone setback was the major factor in the anterior and superior movement of the SOZ and a minor factor in the medial movement. The results indicate that both bone reposition and bone resection are important factors in maximizing surgical results of the reduction malarplasty.

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