Asymmetric Maxillary Expansion Introduced by Surgically Assisted Rapid Palatal Expansion: A Systematic Review

Purpose: A commonly reported complication of surgically assisted rapid palatal expansion (SARPE) that has not been explored extensively is uneven expansion between left and right sides, which requires sec-ondary surgery for correction. This systematic review aims to analyze the prevalence and potential causes of asymmetric expansion in the transverse dimension after SARPE to guide the clinical practice.Methods: Electronic databases and manual search were used to search for original articles published on SARPE on March 11, 2022. Original human studies that recorded the number and percentage of asym-metric expansion after two-piece SARPE were included. The 2020 Preferred Reporting Items for Systemic Reviews and Meta-Analyses guideline was implemented for the quality assessment and data analysis of the included articles. The study was registered at the International Prospective Register of Systematic Reviews under the number CRD42022300782.Results: After applying inclusion and exclusion criteria, 13 articles were included in the final review. The risk of bias was high in 8 studies and medium in the other 5 studies. Overall, the prevalence of asymmetric expansion in the transverse dimension (different amount of expansion between left and right sides) was 7.52%, with 12.90% of patients involved receiving a second surgery for correction. Expander design did not significantly affect the rate of asymmetry expansion. Pterygomaxillary fissure release significantly increased the rate of asymmetry expansion (11.02% vs 5.08%, P < .001). In comparison, lateral nasal wall osteotomy (4.26% vs 14.77%, P < .001) and release of the nasal septum (5.22% vs 17.15%, P < .001) significantly lowered the rate of asymmetry expansion, respectively.Conclusions: Asymmetric dentoskeletal expansion between left and right sides is a common complica-tion of SARPE procedures, mostly caused by variations in surgical cuts. However, the risk of bias in currently available publications is high. Further studies are warranted to fully understand the causes of asymmetric expansion. (c) 2022 American Association of Oral and Maxillofacial SurgeonsJ Oral Maxillofac Surg 80:1902-1911, 2022