Papers by Keyword: Unidirectional Porous Hydroxyapatite (UDPHAp)

Abstract: Regenos® is a unidirectional porous hydroxyapatite (UDPHAp) bone substitutes, and the most distinctive feature of UDPHAp is its interconnected porous structure. We used Regenos® for the bone defect while distal radius fracture surgery with metal fixation implant. At six months post-operation, CT scans revealed the Regenos® implant was uniformly composed of cortical bone adjacent to the trabecular bone. At one-year postoperatively, we collected a sample of the implanted Regenos® while metal fixation plate removal surgery for histological evaluation. Regenos® implant sample revealed the presence of ossified bone stained green with Villanueva Goldner stain. Our findings demonstrate that Regenos® is a useful bone substitution material in the clinical setting.

Abstract: To evaluate the osteoconductive potential of connected porous hydroxyapatite (HAp), we histologically analyzed the newly formed bone inside unidirectional porous HAp (Regenos^®, Kuraray, Japan; 75% porosity, n=17) and interconnected porous HAp (Neobone^®, Covalent Materials, Japan; 75% porosity, n=10) 26 weeks after their implantation as bone spacers between the split lumbar laminae of goats. As a control, non-connected porous HAp spacers (Apaceram^®, Pentax, Japan; 50% porosity, n=5) were used. After staining non-decalcified samples with Villanueva Goldner, changes in pore shape were evaluated microscopically and new bone formation in HAp spacers was quantitatively analyzed. In addition, blood vessel distribution was evaluated by hematoxylin and eosin staining. Changes in pore shape were observed in 76% of the Regenos^® spacers and 90% of the Neobone^® spacers but were not detected in the Apaceram^® spacers. Only limited new bone formation was observed in the Regenos^® and Neobone^® spacers, whereas vascular-like structures were detected in 82% of the Regenos^®, 70% of the Neobone^®, and 80% of the Apaceram^® spacers. The changes in pore shape were thought to have resulted from the low initial compression strength of the connected porous HAp, which may have limited the inherent osteoconductive potential of connected HAp. Our findings suggest that the maintenance of pore shape is required for promoting new bone formation in connected porous HAp when used as lamina spacers in spinal surgery.

Abstract: Unidirectional porous hydroxyapatite (UDPHAp) was developed which has microstructure in that cross sectionally oval pores 100 ~ 300µm in diameter penetrate through the material, and that is suitable for osteogenesis and angiogenesis.The porosity of the UDPHAp was 75 % and the compression strength was 14 MPa. A cortical bone defect was made at proximal tibia of Japanese white rabbit, and a trapezoidal prisms shaped UDPHAp was implanted. By histlogical evaluation, 2 weeks after implantation, new bone and new capillary was observed inside UDPHAp. Twelve weeks after implantation, new bone formation was observed in 41.6 % of the porous area. The results of this study suggest a great possibility of utilizing it in actual clinical setting as a bone substitution.