Stimulation of neo-angiogenesis by combined use of irradiated and vascularized living bone graft for oncological reconstruction.

Reconstruction for large bone and osteochondral defects following musculoskeletal tumor excision remains challenging. Mega-prosthesis is clearly a useful reconstructive tool. Because the survival time of tumor patients has been increasing due to better treatment options, the aim of our group is to achieve complete biological reconstruction without using any artificial materials. With this approach, durability would not be a limitation. In the present study, we reviewed the biological reconstructive procedures currently available for large bone defects after tumor excision. Devitalized bone autograft is particularly well suited in the region where allografts are not readily available. However, the complication rate, such as infection and spontaneous bone resorption, was unexpectedly high due to non-viable graft. In an attempt to reduce these complications, we have used irradiated bone autograft in combination with free vascularized viable bone graft. In an experimental study, we demonstrated a neo-vascularization effect of vascularized bone graft with devitalized bone autograft, i.e. to convert dead bone into living bone. Clinically, this technique is best indicated for reconstruction of intercalary bone defect, especially tibial shaft. Some degree of articular change occurs after irradiation and cannot be prevented, even with the combined use of vascularized bone graft. In our experience, secondary procedures such as surface replacement prosthesis are necessary to treat the osteoarthritis in such cases, even if the radiological finding is severe. The rationale for a combined vascularized and irradiated bone autograft is the cumulative advantage provided by the biological properties of the former with the mechanical endurance of the latter.