Fabrication of Vascularized Bone Grafts Using Ceramic Chambers

Abstract

The present study was designed to create a vascularized bone graft combining the osteogenetic potential of bone marrow cells, and vascular bundle implantation in a hydroxyapatite chamber, using New Zealand white rabbits. A hydroxyapatite chamber was molded into a cylindrical shape, and hydroxyapatite fillers were soaked in an autogenous bone-marrow-cell suspension at a concentration of 1.6 x 10(8)/ml. In one group, the implant was packed with allogenic demineralized bone matrix powder (DBM) and implanted in the mid-thigh subcutaneously, with the epigastric vessels running through the chamber. In a second group, the chamber with bone marrow cells and DBM was implanted subcutaneously, without vascular bundle implantation. The control group consisted of a chamber without DBM, soaked in venous blood and implanted in the opposite thigh, with the epigastric vessels running through the chamber. Cross-sectional bone area and mineral apposition rate were measured, in addition to newly-formed vessels. After 3 weeks, chambers implanted with bone marrow cells and DBM demonstrated consistent bone formation in the pores of the chamber walls and within the chambers. No evidence of bone formation was noted in the chambers soaked with venous blood. The results indicated that vascular-bundle implantation promoted earlier bone formation with neovascularization in the chambers with bone-marrow cells and DBM. Microangiograms revealed vascular connections between the vascular bundle and soft tissue surrounding the chamber through newly-formed vessels in the chamber wall. These findings support the concept of creating a preformed vascularized bone graft, to reconstruct segmental bone defects.

Neovascularized bone grafts: Experimental investigation

“…Various operating techniques and operated-animal management drawbacks convinced us to finally test our model. Unlike those presented by other authors, [1][2][3][4] our model is a true vascular implant model that considerably facilitates clinical use. We are considering the possibility of applying the "shell" wrapping idea to our model as this is able to give the bone graft a preestablished shape.…”

“…[1][2][3][4] Today, the vascularized bone graft procedure is a standard in reconstructive surgery. 5,6 However, this procedure has limitations, such as the morbidity of the donor site, the shape, the structure, and the mandatory site of the available bone.…”

“…On the contrary, they show direct and indirect signs of neovascularization and neoosteogenesis. [2][3][4] The biological bases of these data are unknown. Given the interest shown in these results, we attempted to evaluate an experimental model for the study of bone neovascularization inducible by means of a vascular implanting procedure that could prove interesting and useful both biologically and clinically.…”

Experimental Study of Vascularized Tissue-Engineered Bone Grafts

“…Mizumoto and colleagues developed "preformed vascularized bone grafts" utilizing the osteoinductive ability of demineralized bone matrix powder and osteoprogenitor cells in bone marrow with vascular bundle implantation in a hydroxyapatite ceramic chamber. 21 Yajima et al reported a "prefabricated vascularized periosteal graft" that utilized the osteogenic potential of the periosteum and hydroxyapatite ceramic. 22,23 Unfortunately, these methods have not yet been applied in clinical cases.…”

Imaging Analysis of the In vivo Bioreactor: A Preliminary Study

“…The in vivo bioreactor consists of a surgically implanted vascularized coral hydroxyapatite scaffold in which bone production has been accelerated with the addition of bone morphogenetic protein 2 (BMP2). Using historical precedents [3,9,10], we created a reliable in vivo bioreactor sealed from the host's surrounding tissues except for a lone vascular pedicle that reproducibly produces new bone.…”