A dynamic spine stabilization device is provided that includes at least
one force imparting member, e.g., a spring. The force imparting member is
adapted to deliver a force of between about 150 lb/inch and 450 lbs/inch,
and restrict the relative travel distance between said first and second
pedicles to a distance of between about 1.5 mm and 5 mm. The spinal
stabilization devices also have a minimal impact on the location of the
center of rotation for the spinal segment being treated. By providing
resistance in the noted range and restricting the travel distance to the
noted range, it has been found that the stabilization device provides a
desired level of stabilization, as reflected by range of motion values
that closely approximate pre-injury range of motion levels. In addition,
the resistance levels are not so high as to alter the location of the
center of rotation of the treated spinal segment from its normal
anatomical location to levels previously obtained, thereby permitting
substantially unimpeded angular motion despite the posterior presence of
a stabilization device.