170. Evaluating The Impact of Early Mandibular Distraction Osteogenesis on Obstructive Sleep Apnea in Patients With Robin Sequence: A 20-year Perspective

PURPOSE: Mandibular distraction osteogenesis (MDO) has emerged as a powerful technique for airway management in patients with Robin Sequence (RS). The optimal age to perform MDO in RS patients has yet to be rigorously investigated. In this study, we evaluate the role of surgical timing in optimizing respiratory outcomes after MDO over a 20-year period. METHODS: A retrospective review of patients with RS who underwent MDO at a major children’s hospital between 2004 and 2023 was conducted. Patients without both pre-and post-operative polysomnography were excluded. The primary outcome of interest was the Obstructive Apnea-Hypopnea Index (OAHI), classified as mild for OAHI 1-5, moderate for OAHI 6-10, and severe for OAHI >10. Secondary outcomes included major postoperative complications requiring reoperation or readmission, supplemental oxygen requirement at discharge, and post-MDO tracheostomy. Statistical analyses were performed using piecewise regression, Pearson’s chi-square, and Student’s T-tests. RESULTS: A total of 63 patients with RS met the inclusion criteria. Patients had a median age of 5.85 weeks at the time of MDO. After MDO, patients demonstrated an average OAHI reduction of 24.7 events per hour, corresponding to a mean post-operative OAHI of 8.7 ± 3.9. Piecewise linear regression identified a temporal threshold of 4 weeks, above which the relationship between age at surgery and OAHI reduction changed significantly. The mean OAHI reduction for those who underwent MDO before the age of 4 weeks was 19.6 ± 4.6, while that for those who underwent MDO after 4 weeks was 26.8 ± 3.6 (p<0.05). The early cohort had significantly lower postoperative average highest-end tidal CO2 volume (44.3 ± 0.7 mmHg vs 47.9 ± 0.6 mmHg, p<0.05). Postoperatively, the early cohort also had a higher proportion of patients in the mild OAHI category (48.3% vs 23.5%, p<0.05). Major complications, supplemental oxygen at discharge, post-MDO tracheostomy, syndromic conditions, cleft palate, and cardiopulmonary diagnoses did not vary between cohorts. CONCLUSION: Patients who underwent MDO before four weeks of age were significantly more likely to have mild obstructive sleep apnea (OSA) postoperatively, and lower postoperative highest-end tidal CO2 volumes. These findings suggest early intervention with MDO may be optimal for improving OSA in patients with RS. Neonatal OSA can lead to impaired growth and development, cardiovascular morbidity, and can even be life-threatening. Therefore, MDO at 4 weeks or before is a suitable option for RS patients to help mitigate these severe risks.