Patent ID: 8414592

Claim:
A device for determining an optimal size of an intervertebral implant to be inserted within an intervertebral space between two vertebrae in a patient, comprising: a movable posterior rod operatively connected to first and second posterior distracting members, the posterior distracting members being movable in opposing directions to each other and radially relative to a longitudinal axis of the posterior rod in response to rotation of the posterior rod so that the posterior distracting members move toward or away from the vertebrae defining the intervertebral space, the posterior rod having markings corresponding to the distance that the posterior distracting members have moved for measuring posterior disc height; a movable anterior rod operatively connected to first and second anterior distracting members, the anterior distracting members being movable in opposing directions to each other and radially relative to a longitudinal axis of the anterior rod in response to rotation of the anterior rod so that the anterior distracting members move toward or away from the vertebrae defining the intervertebral space, the anterior rod having markings corresponding to the distance that the anterior distracting members have moved for measuring anterior disc height; the posterior and anterior rods being movable in a longitudinal direction, the anterior rod including a linear scale and the posterior rod including a position indicator for measuring the distance between the distal end of the posterior rod when the posterior distracting member is positioned at a first position corresponding to a posterior end of the intervertebral space and the distal end of the anterior rod when the anterior distracting member is positioned at a second position corresponding to an anterior end of the intervertebral space; the first posterior distracting member and first anterior distracting member each having a terminal end that engages a first load sensor plate, the first load sensor plate being movable in response to movement of either the first posterior distracting member or the first anterior distracting member; a first handle pivotally connected to a proximal end of the first load sensing plate and a second handle pivotally connected to a proximal end of the second load sensing plate, the first and second handles pivotally connected to one another; a protractor disposed relative to the handles to allow measuring the angular orientation between the first and second handles; and a transducer for measuring the force applied during distraction of the intervertebral space.