Correlation Between Soft and Hard Tissue Changes in the Zygomaticomaxillary Region After Bone Contouring Surgery for Fibrous Dysplasia-A Preliminary Study.

PURPOSE: The purpose of the present study was to determine the correlation between the soft and hard tissue changes in the zygomaticomaxillary region after facial bone contouring surgery for patients with craniofacial fibrous dysplasia (FD).

MATERIALS AND

METHODS

The present study was a retrospective case series that reviewed the cases of 13 patients with craniofacial FD in the zygomaticomaxillary region who had undergone navigation-guided facial bone contouring surgery from January 2013 to October 2017. Pre- and postoperative computed tomography (>3 months) were collected. The pre- and postoperative soft and hard tissues were placed in the same spatial coordinate system using multipoint registration to measure the distances between the corresponding pre- and postoperative points of the soft and hard tissues. The outcome variable was the corresponding soft tissue change. The correlation between the hard and soft tissue changes was obtained using correlation analysis with SPSS software (IBM Corp, Armonk, NY). The linear regression equation of the soft and hard tissue changes was used to predict the corresponding soft tissue changes.

RESULTS

The Pearson correlation coefficient of the zygomatic region was 0.954 (P < .001) and the coefficient for the maxillary region was 0.758 (P < .001). The linear regression index (R2) for the zygomatic and maxillary regions was 0.910 (P < .001) and 0.575 (P < .001), respectively. The β value of the linear regression equation for the zygomatic and maxillary regions was 0.815 (P < .001) and 0.52 (P < .001), respectively.

CONCLUSIONS

The soft and hard tissue changes were highly correlated in both the zygomatic area and the maxillary area, and the variance of the maxillary area was slightly greater than that in the zygomatic area. This implied that the change of 1 mm of bone tissue along the tangent direction of the bone contour will cause a change of 0.815 mm in the soft tissue in the zygomatic region and 0.52 mm in soft tissue in the maxillary region.