Acceleration of Distraction Osteogenesis With Drug-Releasing Distractor

The aim of this study was to develop an internal distractor to release a drug to the distraction site during the distraction process and to investigate whether intermittent bone morphogenetic protein 2 (BMP-2)-containing chitosan hydrogel infusion will improve radiologic and histologic parameters of distraction osteogenesis (DO) when compared with control groups. Experimental groups were control group (n = 6), 2-μg single-dose BMP-2-chitosan hydrogel-infused group (n = 6), and 2-μg intermittent BMP-2-containing chitosan hydrogel-infused group (n = 6). In intermittent BMP-infused group, certain amount of BMP-2 loaded chitosan hydrogel injected into the distraction gap for controlled BMP release from the chitosan with every turning of the geared rod of the distractor. Radiologic and histologic evaluation methods have been conducted. The results of the analysis demonstrated that the newly developed distractor effectively stabilized the DO site while allowing intermittent BMP-chitosan infusion. Application of a BMP-2-chitosan hydrogel infusion to the distraction zone facilitates ossification. Intermittent infusion of BMP-2-containing chitosan hydrogel by use of a developed internal distractor increases ossification even more at the site of DO.