Evaluation of Airway Dimensions Following Mandibular Setback with Surgery-First Orthognathic Versus Conventional Orthognathic Approach.

Abstract

To evaluate changes in airway dimensions following mandibular setback with conventional orthognathic approach (COA) and surgery-first orthognathic approach (SFOA). Treatment records of 20 patients who underwent mandibular setback with SFOA/COA were divided into two groups (COA and SFOA, ten patients in each group). Acoustic pharyngometry values were obtained at T0 (01week prior to surgery), T1 (01-month post-surgery) and T2 (01-year post-surgery). Percentage change in mean volume and area was obtained at T1 (T1-T0) to evaluate airway changes and at T2 (T2-T1) to compare relapse of airway changes in both groups. Changes in airway per mm setback at T1 (T1-T0) and T2 (T2-T1) were also obtained in both groups. For both parameters, SFOA showed greater reduction at T1 and greater relapse at T2 as compared to COA. The reduction in airway volume at T1 was 0.56mm/mm setback in COA compared to 1.06mm/mm setback in SFOA (P-value > 0.05). The relapse in airway volume at T2 was 0.15mm/mm setback in COA compared to 0.25mm/mm setback in SFOA (P-value > 0.05). The reduction in area at T1 was 0.062mm/mm setback in COA compared to 0.110mm/mm setback in SFOA (P-value > 0.05). The relapse in area at T2 was 0.016mm/mm setback in COA compared to 0.034/mm setback in SFOA (P-value < 0.05). In setback cases, SFOA has greater airway reduction immediate post-surgically and greater relapse at 01-year follow-up. Predicting these changes at diagnostic and treatment planning stage may prevent potential adverse events on airway.