This systematic review and meta-analysis aimed to determine the optimal timing for mandibular distraction osteogenesis in children with craniofacial microsomia based on long-term outcomes and relapse rates.

A comprehensive search of PubMed, Embase, Cochrane Library, and Web of Science was conducted for studies published up to September 2024. Eligible studies included children aged ≤16 years with CFM who underwent MDO, with follow-up duration exceeding one year. The included population was divided into two groups based on age: children younger than 6 years and those aged 6–16 years. The primary outcome was the relapse rate measured by ramus height ratio, and secondary outcome was occlusal cant. Statistical analyses included heterogeneity assessment, random-effects modeling, and subgroup analysis based on follow-up duration.

Ten studies, comprising 175 patients, were included. The pooled relapse rate based on ramus height ratio was 67.8% (CI: 35.8–93.4%) for children under 6 years and 72.5% (CI: 10.5–94.4%) for those aged 6 years or older, with no statistically significant difference. Subgroup analysis showed that relapse rates increased significantly after five years of follow-up, suggesting progressive asymmetry due to slower growth on the affected side. When occlusal cant was used as a metric, higher relapse rates were observed in children over 6 years 95.6% (CI: 28.9–65.1%) compared to younger patients 46.8% (CI: 83.9–100%).

Despite early MDO providing psychosocial and developmental benefits, relapse rates remain high across all age groups, complicating the determination of an optimal timing. Long-term monitoring, individualized treatment plans, and refined severity grading systems are essential for improving outcomes in CFM patients. Future research should include standardized methodologies, larger groups, and advanced imaging techniques to optimize treatment strategies.