Affiliation:
1. Children’s Healthcare of Atlanta, Atlanta, GA, USA
Abstract
Internal distraction devices for severe midface hypoplasia are often criticized for their distraction at a single pivot point, resulting in “mid-face tipping,” a phenomenon which is in part related to the differential resistance of the soft tissues at orbital and maxillary levels. To address this deficiency, we present our early experience with an internal bi-level midface distraction system. Four patients underwent midface advancement with an internal bi-level distraction system. The specifics of design, application, distraction, and removal are detailed. Hospital records were reviewed to capture patient demographics, length of stay, OR times, and complications. Relevant cephalometry was performed pre- and post-operatively, and compared. In 2015, 4 patients with severe mid-face hypoplasia were treated with an internal bi-level mid-face distraction system. The mean age was 13.5 ± 1.7 years. The mean operative time was 269.7 ± 67.4 min. The mean LOS was 10 ± 7.4 days. The on-table distraction was 5 mm. Distraction subsequently proceeded at a variable rate of 0.5 to 1.0 mm daily with a maximal distraction of 20 and 30 mm at orbital and maxillary levels, respectively. Mean time to distractor removal was 11.2 ± 1.1 weeks. Device design allowed facile removal through minimally invasive incisions. Cephalometry was seen to progress towards age-matched norms. There were no major complications. Minor complications included breakage of the vertical component of the maxillary arm at the time of device removal in 1 patient. By allowing real-time adjustment at the orbital and maxillary levels to combat differential resistance, early experience with our device maximizes occlusal advancement without overcompensating orbital translation.