INTRAOSSEOUS PLATING - A NEW METHOD FOR BIODEGRADABLE OSTEOFIXATION IN CRANIOFACIAL SURGERY

Biodegradable miniplates and screws offer special possibilities for su rgical techniques because the removal operation is avoided. In areas b eneath thin skin, intraosseous plating could be preferable to avoid pa lpability and transient swelling during resorption. The tissue reactio n to a 0.5-mm-thiek self-reinforced poly-L-lactide (SR-PLLA) plate fix ed with an SR-PLLA miniscrew was studied histologically and histomorph ometrically after implantation into the calvarium of six young sheep. After followup periods of 6, 20, and 52 weeks, no signs of adverse tis sue reaction such as clinically manifest foreign body reaction or hist ologically manifest osteolysis were noted. By 52 weeks the implants we re largely in direct contact with remodeled, dense bone tissue. No sig ns of fragmentation or resorption were noted in the intraosseous parts of the implants, whereas the screw head had been fragmented and was u ndergoing resorption at 52 weeks. The screw head is unnecessary in thi s plating method and could have been removed with a hot wire loop. The excellent biocompatibility of the mechanically strong, resorbable SR- PLLA plate with miniscrew fixation provides a possibility for intraoss eous plating in less loaded craniofacial areas, especially in areas wi th very thin soft-tissue coverage.