Patent ID: 8348983

Claim:
A surgical bone screw, comprising: an elongate screw body having at least a shank portion having a proximal end, a distal end, a threaded portion, and a passage extending between the proximal and distal ends, the shank portion extending along a central longitudinal axis from the proximal end to the distal end, the shank portion having an external surface that is conductive along the shank portion, the shank portion having an upper terminal proximate the proximal end and a lower terminal proximate the distal end, the upper terminal being coaxial with the longitudinal axis, the upper terminal defining the uppermost portion of the shank portion and being accessible from a proximal direction along the longitudinal axis, the upper and lower terminals electrically isolated from the external surface; an electrical conductor disposed inside the passage and electrically connecting the first and second terminals; an insulation portion disposed inside the passage and around the electrical conductor; a first insulating spacer fixed at the proximal end of the shank portion such that the upper terminal is exposed on a first surface of the first spacer and the electrical conductor passes through the first spacer; and a second insulating spacer fixed at the distal end of the shank portion such that the lower terminal is exposed on a first surface of the second spacer and the electrical conductor passes through the second spacer, the insulation portion and the first and second spacers electrically insulating the first and the second terminals from surrounding portions of the screw body so that when the screw is driven into bone tissue and a stimulating current is applied to the first terminal the current is directed substantially through the conductor to flow into tissue adjacent the second terminal without shunting by other tissue that surrounds the screw body.