Metanalysis of alloplastic materials versus autologous fat for injection augmentation pharyngoplasty treatment of velopharyngeal insufficiency

Background: Velopharyngeal insufficiency (VPI) can cause resonance, speech and feeding problems. While reconstructive palatoplasty and surgical pharyngoplasty techniques are the mainstay of treatment for severe VPI, injection augmentation pharyngoplasty offers a minimally invasive approach in patients with mild-to-moderate VPI. Methods: We conducted a systematic review of the literature available on PubMed and Embase from 1990 to 2019 including studies that addressed VPI, incompetence, or dysfunction managed with injection augmentation. Patient demographics, etiology of VPI, injection material, volume of injection, number of injections, complications and both subjective and objective outcomes were recorded. Results: Twenty-nine studies met our inclusion criteria encompassing 587 patients, ages 3-75 years (mean = 16) who underwent injection pharyngoplasty. Injection materials included glutaraldehyde cross-linked (GAX) collagen (n = 5), calcium hydroxyapatite (n = 36), dextranomer and hyaluronic acid (n = 72) and autologous fat (n = 471). Follow-up averaged 15.4 months (range = 2-60 months). Functional improvements in nasality were recorded in a large proportion of patients (0.79, 95% CI 0.75 to 0.82). However, a greater proportion of patients in the synthetic materials group demonstrated either reduced or resolved hypernasality compared with those receiving autologous fat injections (chi 2 = 7.035, n = 91/103 vs. 255/338, p = 0.008). Complete velopharyngeal gap closure post-injection was achieved at a higher frequency with injection of synthetic materials compared with autologous fat (chi 2 = 11.270, n = 61/69 vs. 58/91 p = 0.001).r Conclusion: Injection pharyngoplasty offers a minimally invasive alternative intervention for treatment of VPI secondary to small velopharyngeal gaps. Patients treated with synthetic materials experienced a greater improvement in velopharyngeal closure and a corresponding improvement in resonance balance.