Stability outcomes of internal and external distractors in maxillary distraction osteogenesis for cleft lip and palate: A systematic review

Cleft lip and palate (CLP) often result in maxillary hypoplasia due to surgical scarring and impaired growth. In such cases, distraction osteogenesis (DO) is a well-established technique for achieving maxillary advancement. Both internal and external distractors are widely applied, yet their relative long-term skeletal stability is not known. To systematically evaluate the long-term skeletal stability of Le Fort I osteotomy with distraction osteogenesis using internal and external distraction devices in managing maxillary deficiency among CLP patients. Following PRISMA guidelines and with prior PROSPERO registration (CRD420251026923), a comprehensive search of PubMed, Scopus, and Web of Science databases was conducted up to April 6, 2025. Studies involving CLP patients who underwent maxillary distraction osteogenesis with either internal or external devices were included. Data extraction and quality assessment were performed using the Newcastle-Ottawa Scale and ROBINS-I tools. Thirteen studies met the inclusion criteria. Internal distractors demonstrated favorable long-term skeletal stability, with reported relapse rates ranging from 0% to 15%. External distractors, most notably the rigid external distractor (RED), produced more advancement but had increased rates of early relapse (as high as 30%). Bone-borne RED systems had better results compared with tooth-borne systems. The majority of relapses happened during the first 6 months following distraction, most notably in the vertical plane. Le Fort I osteotomy was the most commonly employed surgical procedure. External distractors allowed greater advancement but were associated with relapse rates up to 30%, especially in the vertical plane. Internal distractors, while offering reduced vector control, provided superior long-term skeletal stability (relapse 0–15%) and improved patient comfort.