Spinal fixation system having locking and unlocking devices for use with a multi-planar, taper lock screw

A multiplanar taper lock screw as a connecting device for securing a connecting rod to bone comprising:

• a screw inner housing and a screw outer housing, said screw outer housing being circumferentially disposed around at least a portion of said inner housing and being sized and configured to be capable of slidable movement along a common longitudinal axis of said inner housing and outer housing, said outer housing at or near an upper portion of said housing defines an annular flange projecting outwardly from at least a portion of an outer wall of said outer housing;
• a screw comprising a threaded screw shaft and a superiorly positioned screw head, said screw shaft being configured to facilitate penetration and attachment to bone, said screw head being generally spherical and having a screw head gripping surface that is configured to receive a torsional tightening or loosening tool;
• an articulation recess that is defined in the lower portion of said inner housing, said articulation recess being of complementary size and configuration to retain said screw head within said inner housing while allowing said screw head to be capable of rotation within said articulation recess,
• a screw shaft exit portal, which is defined by said inner housing at the lowest portion of said articulation recess, is sized to retain said screw head within said articulation recess while being of sufficient size to allow multi-planar rotational articulation of the screw head and the screw shaft exiting from said articulation recess;
• a connecting rod;
• an inner housing connecting rod slot defined in the upper portion of said inner housing, said inner housing connecting rod slot being sized and configured such that a selected compressive force on said inner housing can effect a releasable locking contact of said inner housing connecting rod slot against the connecting rod contained therein;
• said inner housing and said outer housing having a generally complementary tapered shape for the respective opposing surfaces such that as said outer housing is slidably moved in an upward direction relative to said inner housing, said outer housing contacts said inner housing so as to be capable of producing a compressive force on the portion of the inner housing so contacted by said outer housing,
• wherein said compressive force is sufficient to be capable of compressing said inner housing against said screw head contained within said screw head recess and said connecting rod contained within said inner housing connecting rod slot so as to releasably hold said screw head and said connecting rod in a fixed position relative to said inner housing, wherein said inner housing, said outer housing, and said connecting rod each has a proximal surface, said proximal surfaces being substantially coplanar when said multiplanar taper lock screw is in a locked position.

A spinal fixation system comprising:

• a taper lock screw including an inner housing, an outer housing, the inner housing being adapted and configured to receive a connecting rod therein, wherein the outer housing is configured and adapted to apply a compressive force to the inner housing to releasably secure the connecting rod within the inner housing when the taper lock screw is in a locked position, the outer housing including a proximally disposed circumferential flange;
• and
• a locking device comprising:
• an outer housing having a first end and a second end and a lumen defined by said housing and communicating between said first and said second end, said lumen defining inwardly directed push rod cam surfaces;
• an actuator handle operationally connected to said housing and configured to be capable of manual operation to activate said locking device;
• a push rod slidably disposed within said housing and pivotally connected at a first end to said actuator handle, said push rod having push rod cam surfaces, said push rod having a second distally disposed end configured to make contact with a connecting rod when said push rod is forced downward within said lumen, the push rod being adapted and configured to contact an upper surface of the inner housing to provide a downward force relative to the outer housing to transition the taper lock screw to the locked position;
• a compression slit having tensile memory and being defined in the distal portion of said housing, said compression slit being capable of expanding outwardly as internal force is exerted on the inner walls of said lumen by movement of said push rod upward or downward with said lumen;
• and
• a housing terminus at said second end of said device, said terminus being configured to have inwardly directed grasping projections, said grasping projections being configured to releasably connect to the proximally disposed circumferential flange on the taper lock screw.

A spinal fixation system comprising:

• a taper lock screw including an inner housing, an outer housing, the inner housing being adapted and configured to receive a connecting rod therein, wherein the outer housing is configured and adapted to apply a compressive force to the inner housing to releasably secure the connecting rod within the inner housing when the taper lock screw is in a locked position, wherein the outer housing includes a receiving element, the receiving element being a radial extension at or near a proximal end of the outer housing;
• and
• an unlocking device comprising:
• a housing having a first end and a second end and an unlocking lumen defined by said housing and communicating between said first end and said second end, said unlocking device housing having unlocking device cam surfaces;
• an actuator handle operationally connected to said housing and configured to be capable of manual operation to activate said unlocking device;
• a push rod slidably disposed with said housing and pivotally connected at a first end to said handle, said unlocking device push rod defining push rod recesses positioned and configured to interact with said unlocking device cam surfaces defined on an inner wall of said unlocking device lumen when said push rod is moved through said unlocking lumen, said push rod having a second distally disposed end configured to make contact with an unlocking device connecting rod when said push rod is forced downward within said lumen;
• an outer sleeve circumferentially disposed around at least a portion of a lower part of said unlocking device housing, said outer sleeve being connected to said unlocking device push rod by a connecting pin that is slidably disposed in a connecting pin slot defined through the wall of said unlocking device housing;
• and
• at least a pair of screw grasping elements defined at the second end of said unlocking device housing, said screw grasping elements being configured to releasably connect to the receiving element of the taper lock screw.

A method for fixing bone, the method comprising:

• providing a spinal fixation system comprising:
• a connecting rod;
• a taper lock screw having an inner housing and an outer housing, said inner housing being provided with unlocking tool receptors and said outer housing being circumferentially disposed around at least a portion of said inner housing and having a proximal, outwardly directed flange, the flange at least partially circumferentially disposed on the outer housing, wherein the outer housing and the inner housing are translatable relative to one another to transition the taper lock screw among a locked position, an unlocked position, and a partially locked position, and wherein the inner housing is adapted and configured to receive the connecting rod therein, and wherein the outer housing, the inner housing, and the connecting rod each has a proximal surface, the proximal surfaces being substantially coplanar when the taper lock screw is in the locked position;
• a locking device specifically configured to be capable of releasable connecting to and operationally interacting with said flange of said taper lock screw to lock said screw;
• and
• an unlocking device specifically configured to be capable of releasably connecting to and operationally interacting with said inner housing unlocking tool receptors of said taper lock screw to unlock said screw;
• implanting said screw into the bone of a subject;
• positioning said screw and said connecting rod into a selected position;
• locking said connecting rod into position within said inner housing of said screw using said locking device;
• and if adjustment or removal of said connecting rod or said screw is required, using said unlocking device to unlock said screw.

A kit for fixing bone, the kit comprising:

• a spinal fixation system comprising:
• a connecting rod;
• a taper lock screw having an inner housing and an outer housing, said inner housing being provided with unlocking tool receptors and said outer housing being circumferentially disposed around at least a portion of said inner housing and having a proximal, circumferentially disposed, outwardly directed flange, wherein the outer housing and the inner housing are translatable relative to one another to transition the taper lock screw among a locked position, an unlocked position, and a partially locked position, and wherein the inner housing is adapted and configured to receive the connecting rod therein, and wherein the outer housing, the inner housing, and the connecting rod each has a proximal surface, the proximal surfaces being substantially coplanar when the taper lock screw is in the locked position;
• a locking device specifically configured to be capable of releasable connecting to and operationally interacting with said flange of said taper lock screw to lock said screw;
• and
• an unlocking device specifically configured to be capable of releasably connecting to and operationally interacting with said inner housing unlocking tool receptors of said taper lock screw to unlock said screw;
• and
• at least one additional tool configured to facilitate insertion or connection of said multi-planar screw and said connecting rod to bone.