The present study evaluated the use of this self-activated shape memory alloy (SMA) device, with a focus on its effects in the region under the periosteum.
Materials and methods : Twelve Japanese white rabbits were used in this study. The device was inserted under the periosteum at the forehead. In the experimental group, the device was pushed, bent, and attached to the bone surface and fixed with a titanium screw. In the control group, the device was inserted with no activation, and in the experimental groups, it was inserted and activated after a latency period of 14 days. Groups were also defined for consolidation periods of 5 and 8 weeks after surgery. Rabbits were sacrificed 5 and 8 weeks after the operation and newly formed bone was histologically and radiographically evaluated.
Results: No complications related to the materials used at the sites of intervention, before, during, or at the end of the experimental phase or infection within or around the device were observed in any animal. The quantitative data by the area and the occupation of newly formed bone indicated that the experimental group had a higher volume of new bone than the control group at each consolidation period. Histologically, some newly formed bone was observed and most of the subperiosteal space underneath the device was filled with fibrous tissue, and a thin layer of immature bone was observed in the control group. In the experimental group, multiple dome-shaped bones, outlined by thin and scattered trabeculae, were clearly observed under the SMA mesh device.
Conclusion : The use of self-activated devices for the periosteal expansion technique may make it possible to avoid donor site morbidity, trans-skin activation rods, any bone-cutting procedure, and the following intermittent activation procedure.