Risk Factors of Avulsion Fracture after Iliac Crestal Flap for Jaw Reconstruction

The iliac crestal flap is often used in maxillofacial reconstruction surgery because it has a similar bone contour to jaw bone. However, complications occur frequently in this flap, and the avulsion fracture of the anterior superior iliac spine (ASIS) occurs only in rare cases. The purpose of this study is to evaluate the risk factors affecting fractures that may occur after iliac crestal flap harvesting. In this study, we performed preoperative and postoperative CT scans of the iliac bones of 22 patients who underwent iliac crestal flaps between February 2013 and July 2019. Three of these patients had fractures within 1 month after surgery. After converting DICOM files to a three-dimensional model using Mimics software, some reference points were defined for analysis. The patients were classified into fracture and non-fracture groups. The patients’ age and sex, harvested bone, residual bone and absolute bed rest (ABR) periods were investigated. The patients’ age and sex were not associated with fracture occurrence. There was a statistically significant difference in the width of the anterior–superior part of residual bone. The fracture group showed statistically significantly shorter ABR periods. In the case of the iliac crestal flap, it was found that the factors that can affect the occurrence of fractures are the width of the residual bone and the ABR period. Iliac avulsion fracture can be prevented when the remaining bone is sufficient and the ABR period is prolonged sufficiently.