What is the Success Rate of Repeat Alveolar Bone Graft?

BACKGROUND: Success rates for alveolar bone grafting range from 30 to 96%. There is limited information regarding the success of repeat grafts. PURPOSE: The purpose of this study was to determine the radiographic success rate of repeat alveolar bone grafts. STUDY DESIGN: The study designs was a retrospective cohort study of patients who underwent repeat grafting by 1 surgeon over 15 years. To be included, subjects had to have: cleft lip and alveolus and a cone-beam computed tomography (CBCT) scan obtained >6 months after repeat graft. Patients were excluded if CBCT was inadequate. PREDICTOR VARIABLE: Predictor variables were sex, age at repeat graft, cleft type, presence of an erupted canine, premaxillary osteotomy at time of repeat graft, presence of a visible oronasal fistula, size of bony defect, presence of a bony palatal bridge, and whether the surgeon who performed the repeat graft also performed the initial graft. MAIN OUTCOME VARIABLE: The outcome variable was graft success determined using CBCT assessment and defined as a score of >3 out of 4 in each domain: vertical bone level, labiopalatal thickness, and piriform symmetry. COVARIATES: The covariates were time from bone graft to CBCT (months) and age at time of CBCT (years). ANALYSES: Frequency distributions, relative risk with 95% confidence intervals, medians, and interquartile ranges were calculated. Pearson c2 and Fisher exact tests were performed to determine predictors of outcome. A P < .05 was considered statistically significant. RESULTS: Fifty subjects (54% male) who had repeat bone grafting to 59 cleft sites were included. Median follow-up time from repeat graft to CBCT was 7.0 months (interquartile range: 5.9 months). The radiographic success rate was 81.4%:91.7% if the same surgeon performed both initial and repeat grafts, but 78.7% if initial graft was completed by another surgeon (P = .43). CONCLUSION AND RELEVANCE: Despite being a multifactorial issue, extensive and bilateral clefts, the presence of an erupted tooth in the cleft area, a visible oronasal fistula, and concomitant osteotomy of the premaxilla are warning signs of the possibility of failure. Performing repeat alveolar bone grafting by an experienced surgeon appears to increase the chance of success.