Repair of experimental calvarial defects with Bio-Oss particles and collagen sponges in a rabbit model.

Various materials have been used for reconstruction of both acquired and congenital calvarial defects. Unfortunately, each has its limitations. Autologous bone grafts have irregular rates of resorption that may require secondary corrective surgery, and individual harvest sites have limited stores that can necessitate additional donor locations. Alloplastic materials have unlimited quantities and volume stability but they may not become incorporated and are associated with a higher incidence of infection. The optimal bone substitute should stimulate new bone formation and permanently supplant the temporary space filler, thereby reconstituting the surgical defect. We evaluated 2 newly available bone substitutes, resorbable natural bone mineral (Bio-Oss particles) and a combination of collagen and natural bone mineral collagen combination (Bio-Oss sponges), to repair calvarial defects in an adult, male, New Zealand white rabbit model. We found that the particulate Bio-Oss material resorbed and then underwent the normal physiological stages of bone remodeling. The collagen and Bio-Oss combination was replaced by new bone ingrowth. These materials may have potential for use in the reconstruction of skull defects.

Polyglyconate plates and screws to stabilize zygomatic osteotomies in a rabbit model.

Rigid internal fixation with miniplates and screws continues to be widely used in the correction of both congenital and acquired craniomaxillofacial deformities. This technique allows precise three-dimensional stabilization of bony segments. A number of recent reports have detailed some disadvantages, including potential growth restriction in developing children, bone resorption, infection, extrusion, and palpability. These problems have often necessitated secondary surgery for hardware removal. A biodegradable plate and screw system would eliminate these potential and real problems. Over the last 2 decades, there has been an escalating interest in developing satisfactory biodegradable materials for bony fixation. We have previously reported the initial phases of a long-term evaluation of various biomaterials currently available. The purpose of this study is to examine a biodegradable plate and screw system fabricated from a faster resorbing material--polyglyconate. This system would be applicable to pediatric reconstructive problems. Earlier studies have shown its tissue compatibility and feasibility for multiple surgical uses. Osteotomies were created at the midpoint of each zygomatic arch of 42 adult male white New Zealand rabbits. The animals were then divided into two equal groups. The first group served as a control and the bony segments were permitted to heal without stabilization, whereas in the experimental group, the bony segments were stabilized with biodegradable plates and screws made from polyglyconate. Animals were then sacrificed at 2, 4, 6, 8, 12, and 16 weeks, at which time radiographs were obtained. Zygomatic complexes were then removed en bloc, and routine hematoxylin and eosin slides were made for light microscopy. Without fixation, fracture segments became significantly displaced.(ABSTRACT TRUNCATED AT 250 WORDS)

Reconstruction of calvarial defects with anorganic bovine bone mineral (Bio-Oss) in a rabbit model.

Reconstructive surgeons have employed various procedures using either autogenous or alloplastic materials to repair cranial defects secondary to trauma, extirpative surgery, or congenital anomalies. Currently, the choice appears to be dependent on the personal choice or background of the operating surgeon. For years, our preference has been to use calvarial bone grafts as our primary source of reconstructive material. Disadvantages include uneven resorption of the bone grafts and limited quantities. For these reasons, bony substitutes present new possibilities for reconstruction of craniomaxillofacial defects. We evaluated Bio-Oss, which is a natural bone mineral derived from a bovine source that is chemically and physically identical to human bone, as a possible replacement material to reconstruct skull defects in a rabbit model.