S7B-05 SESSION 7B: HFM ROBIN - PART II VIVODOGMA PROJECT MAGNETIC ACTIVATION OF MANDIBULAR DISTRACTION OSTEOGENESIS: FIRST CADAVERIC STUDY

Abstract

Introduction: Here we present the result of a cadaveric study incorporating 10 cadavers. On each, a partial or complete magnetically activated mandible distraction osteogenesis has been performed. Several designs of magnetic distractors have been tested with a resulting improvement between each design. Classical mandibular distraction is performed thanks to devices comprising activation rods protruding in the mouth, therefore, occasioning poor occlusion and discomfort. Our main goal is to free patients of this rod. For that, we used a system of two permanent magnets in interaction. Therefore we work on optimizing the design a functional magnetically activated device for distraction osteogenesis. Methods: A 10 cadavers study was performed. Our devices were implanted on horizontal branches and one on a vertical branch. The surgical procedure was performed on non-pathological adult corpses according to Necker Hospital standards. The devices implanted were the magnetic distractor prototypes. The distraction was tested with and without soft-tissues sutured. The external activator consisted of either a simple magnet or an automatic activating device. To evaluate the distraction’s activation success, we focused on measuring real advancement, the number of turns for activation and activation ratio. Results: Fully-closed distractions were successful with a low activating ratio while rotating the simple external magnet by hand. Both horizontal and vertical activations were successful without suture of soft-tissues, achieving an activation ratio of sixty-six percent (two millimeters for sixty turns) using the automatic activating device. The same results were obtained with soft tissues sutured back into position while making an opening for the internal magnet edge to be exposed on the jaw. Conclusion: As a first step, this cadaveric study demonstrates the relevancy of a rod-less magnetic activation of mandibular distraction osteogenesis. The next objective will be to refine our design of both the internal and external devices to increase the activation ratio and fully control it.