Classification of midpalatal suture opening after surgically assisted rapid maxillary expansion using computed tomography.

OBJECTIVE The aim of this study was to classify the opening of the midpalatal suture (MPS) after surgically assisted rapid maxillary expansion (SARME) with disjunction of the pterygomaxillary suture through computed tomography (CT) analysis. STUDY DESIGN Seventy adults with bilateral transverse deficiency of the maxilla underwent SARME with pterygomaxillary disjunction. Seventy tomographies were performed before the surgery and 70 were performed after the final activation. The Hass appliance was used in 29 patients and Hyrax in 41 patients. The MPS opening was classified into 2 types: type I, total MPS opening from the anterior nasal spine to the posterior nasal spine, and type II, total MPS opening from the anterior nasal spine to the transverse palatine suture, with partial or nonexistent opening posterior to transverse palatine suture. RESULTS Type I opening was observed in 22 patients (31.5%), and type II opening in 48 patients (68.5%). In 5 cases, the opening posterior to the transverse palatine suture was paramedian. CONCLUSION Computed tomography allows the evaluation and classification of midpalatal suture openings after SARME with pterygomaxillary disjunction in type I (total) and type II (partial) MPS openings.