Experimental evaluation of a percutaneous injectable biomaterial used in radio-interventional bone-filling procedures

Interventional radiology is beginning to be used in bone pathology. An injectable biomaterial Ethibloc*, composed of alcohol and a vegetal protein (zein), has been successfully used for percutaneous treatment of benign bone lesions. The reasons for this success remained unknown and needed to be understood. In this study, using a rabbit model, an evaluation was made of bone formation and tissue reaction during the first weeks after the injection of this biomaterial. Ethibloc* was injected percutaneously into bone defects in rabbit distal femurs. Three time intervals were studied: 2, 4 and 8 wks. The three control groups constituted unfilled, polymethylmethacrylate (PMMA), and alcohol. Undecalcified bone technique was used for a qualitative analysis and histomorphometric evaluation. A low bone formation was found which was less than in the control groups (PMMA and unfilled). The "Ethibloc group" was characterized by an early inflammatory reaction. Good clinical results obtained with Ethibloc* probably arose, after an initial vascular thrombosis, from a secondary bone reaction and spontaneous osteogenesis obtained after the disappearance of vascular or hyperpression reaction.