Failure Rates Based on Alveolar Cleft Volume: An Analysis of the Critical-Sized Defect for Alveolar Bone Grafting.

Background: Alveolar bone grafting (ABG) using iliac crest bone graft (ICBG) is best practice for children with complete cleft lip and palate. With the advent of recombinant human bone morphogenetic protein (rhBMP-2) and demineralized bone matrix (DBM), excellent results can still be achieved while avoiding donor-site morbidity. This study aims to determine the critical-sized defects by analyzing graft failure rates for ICBG and rhBMP-2/DBM to guide surgeons performing ABG.
Methods: A retrospective review was conducted evaluating patients who underwent ABG from 2016-2022. Patients with preoperative and postoperative cone beam computed tomography (CBCT) imaging were included. Volumetric defect sizes were calculated using preoperative imaging. Graft success criteria were based on both clinical and radiographic outcomes. Logistic regressions analyzed graft failure rates to identify an optimal cutoff, which defined the critical-sized defect.
Results: Ninety-three patients were included. Bone graft cohorts included ICBG (n=30) and rhBMP-2/DBM (n=63). The critical-sized defects were calculated to be 810 mm 3 and 885 mm 3 for ICBG and rhBMP-2/DBM, respectively. There were significantly higher graft failure rates beyond the critical size compared to below for both ICBG (71.4% vs. 0.0%; p<0.001) and rhBMP-2/DBM (65.0% vs. 14.0%; p<0.001).
Conclusion: This study identified critical-sized defects based on alveolar cleft volume for ICBG or rhBMP-2/DBM with higher graft failure rates beyond the predicted thresholds. Distinct ranges in cleft volume were identified where patients might benefit from each select graft option.
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