CT-GUIDED BONE-BIOPSY PERFORMED BY MEANS OF A COAXIAL BIOPSY SYSTEM WITH AN ECCENTRIC DRILL

Thirty-seven consecutive bone biopsies guided with computed tomography were performed in 32 patients by use of three different techniques to penetrate cortical bone and gain access to the lesion. The following instruments were used: a thin bone biopsy needle (12 biopsies), a conventional drill with an outer cannula (six biopsies), and a coaxial biopsy system that consists of a drill with an eccentric tip and an outer cannula (19 biopsies). This eccentric drill makes a hole in the bone larger than the diameter of the cannula and thereby makes it easy to advance the cannula over the drill until the cannula is anchored in the bone. One can then obtain multiple samples through the cannula. The thin bone biopsy needle could not penetrate thick (8 mm thick) cortical bone. The outer cannula was not anchored in the bone when the conventional drill was used. In 16 biopsies, the new coaxial biopsy system penetrated cortical bone with a thickness of 1-8 mm and was anchored there, and lesion samples were obtained through the anchored cannula.