Patent ID: 8386022

Claim:
A tracker device of the type being associated with a surgical instrument and being trackable in space by a CAS system such that at least a position of the surgical instrument is calculable, comprising: a support adapted to be connected to the surgical instrument and supporting at least four different optical elements; at least three optical elements each having a single flat retro-reflective surface and being mounted to the support in a first pattern so as to be detectable by the CAS system along a first range of visibility, with the first pattern defining a first polygon with each corner of the first polygon being a point in a respective one of the three optical elements; and at least three other optical elements separate from said three optical elements, the at least three other optical elements each having a single flat retro-reflective surface and being mounted to the support in a second pattern, with the second pattern defining a second polygon geometrically different from the first polygon, with each corner of the second polygon being a point in a respective one of the three other optical elements so as to be detectable by the CAS system along a second range of visibility, with the first range of visibility and the second range of visibility having at most a common portion; whereby at least a position of the surgical instrument is tracked within the first and the second range of visibility as a function of the detection and identification of any one of the first polygon and the second polygon of the optical elements.