Pharyngeal airway changes following maxillary advancement by distraction osteogenesis among patients with cleft lip and palate: a systematic review and meta-analysis

Objectives: To evaluate the impact of maxillary advancement by distraction osteogenesis (DO) on the pharyngeal airway including the following parameters in patients with cleft lip and palate (CLP), with a secondary focus on long-term changes ≥1 year: palatal pharyngeal space, superior posterior pharyngeal space, middle pharyngeal space, inferior pharyngeal space, epiglottic pharyngeal space, velar angle, velar length, and need ratio. Materials and Methods: A comprehensive search was conducted in Medline through PubMed, Scopus, Cochrane databases, Embase, and Directory of Open Access Journals through October 2024. Studies were assessed for pharyngeal airway changes at three time points: pre-DO (T1), post-DO (T2), and ≥1-year post-DO (T3). Quality was assessed using the National Institute of Health tool for before-after (pre-post) studies with no control group. Meta-analysis was conducted using Cochrane Review Manager (RevMan) Version 5.3. A random effect model assessed the mean difference (MD) in parameters representing the pharyngeal airway at T1, T2, and T3. GRADE criterion assessed the certainty of evidence. The protocol is officially registered with PROSPERO (CRD42023444533). In this systematic review, we followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Results: The meta-analysis included 10 studies with 135 patients. The included studies ranged from fair to good quality. Significant increases were observed in pharyngeal space post-DO, particularly in superior and middle pharyngeal regions. Slight relapse was noted after 1 year, but overall, airway improvement remained significant. Evidence certainty by GRADE assessment revealed high to moderate evidence except for need ratio (low). Conclusions: Maxillary advancement by DO significantly improves pharyngeal airway in CLP patients, with minimal relapse after 1 year.