380 results about "Relative direction" patented technology

Embodiments of an orthopedic implant device and system, and methods for implanting them, are disclosed. The implant may include a receiver member having a channel for accommodating an elongated rod or other longitudinal member, a bone anchoring member such as a screw or hook, and a base member rotatable with respect to the receiver member for retaining the bone anchoring member in the receiver member. The base member is configured to allow at least two different degrees of maximum angulation of the bone anchoring member with respect to the receiver member. The number and relative direction of such angulations are independent of the orientation of the channel or other part of the receiving member.

Interelectrode impedance or electric field potential measurements are used to determine the relative orientation of one lead to other leads in the spinal column or other body / tissue location. Interelectrode impedance is determined by measuring impedance vectors. The value of the impedance vector is due primarily to the electrode-electrolyte interface, and the bulk impedance between the electrodes. The bulk impedance between the electrodes is, in turn, made up of (1) the impedance of the tissue adjacent to the electrodes, and (2) the impedance of the tissue between the electrodes. In one embodiment, the present invention makes both monopolar and bipolar impedance measurements, and then corrects the bipolar impedance measurements using the monopolar measurements to eliminate the effect of the impedance of the tissue adjacent the electrodes. The orientation and position of the leads may be inferred from the relative minima of the corrected bipolar impedance values. These corrected impedance values may also be mapped and stored to facilitate a comparison with subsequent corrected impedance measurement values. Such comparison allows a determination to be made as to whether the lead position and / or orientation has changed appreciably over time. In another embodiment, one or more electrodes are stimulated and the resulting electric field potential on the non-stimulated electrodes is measured. Such field potential measurements provide an indication of the relative orientation of the electrodes. Once known, the relative orientation may be used to track lead migration, to setup stimulation configurations and parameters for nominal stimulation and / or navigation. Also, such measurements allow automatic adjustment of stimulation energy to a previously-defined optimal potential field in the case of lead migration or postural changes.