Effects of alveolar bone grafts vs. orthognathic surgery on cleft palate speech nasalance: a meta-analysis

Patients born with cleft palate frequently struggle with speech nasalance issues, such as hypernasality and hyponasality. Hypernasality results in patients having nasal speech, whereas hyponasality results in patients having a congested voice. To improve speech function, cleft palate patients may undergo numerous surgical interventions. Two of the most common secondary cleft repair surgeries are alveolar bone grafting and orthognathic surgery. The purpose of this meta-analysis was to determine whether one surgical intervention is more effective in addressing hypo- and hypernasality in cleft palate patients. We assessed three key outcomes: change in nasalance scores post- operation, percent change of patients with excess nasal emission post-operation, and presence of hypo/ hypernasality post-operation. We hypothesized that alveolar bone grafts will be superior to orthognathic surgery for addressing speech nasalance. Results from nine studies conducted over 47 years revealed distinct outcomes for bone grafts and orthognathic surgery. Alveolar bone grafts were found to generally improve hypernasality, whereas orthognathic surgery resulted in worsened hypernasality. For each treatment type, both hypo- and hypernasality can be found in patients post-operation, with no statistical indication of immediate changes to hyponasality. Limitations to this analysis included the small sample size used in the component studies, so more research would be helpful for additional understanding. Studies used in the analysis consisted of both cohort studies and randomized controlled trials, resulting in some confounding effects. From a clinical perspective, this meta-analysis has the potential to inspire future studies comparing these surgical methods, which may ultimately enable craniofacial surgeons to enhance nasalance outcomes for individuals with cleft palates.