Rod reducer, compressor, distractor system

Abstract

A compressor/distractor system for operating on a spine is disclosed. The system includes two rod reducers which each advance a spinal rod into the shoulder portion of a pedicle screw. Each rod reducer includes an inner member, an outer member, and a pair of gripping members. Each outer member receives and advances the spinal rod into the pedicle screw. The outer member also includes a through slot which receives the proximal end of each of the pair of gripping members which may limit the longitudinal translation of the outer member with respect to the inner member. The compressor/distractor system may include a compressor/distractor device which has a compressing, a distracting, and a neutral configuration. A method for using the minimally invasive rod reducers with the compressor/distractor system to secure at least two pedicle screws in desired positions on a spinal rod is also disclosed.

What is claimed: 
     
       1. A method for manipulating vertebrae comprising:
 accessing the spinal area of a patient having a pedicle screw secured to each of at least two vertebrae;   engaging each pedicle screw with an inner member having distal and proximal ends defining a longitudinal axis therebetween, the distal end of each inner member receiving a head of the pedicle screw;   advancing an outer member having distal and proximal ends distally along each of the inner members by rotating the proximal end of each of the outer members relative to each inner member, a pair of receiving slots on the distal end of each outer member receiving a portion of a spinal rod, each pair of receiving slots advancing the spinal rod into a saddle portion of the head of each pedicle screw;   attaching a force applying device and a fulcrum to an outer surface of each outer member, the force applying device including first and second hook members and having a compressing configuration when the first and second hook members are attached to each outer member with each of the outer members between the first and second hook members and a distracting configuration when the first and second hook members are attached to each outer member with the first and second hook members between each of the outer members;   manipulating each outer member with the force applying device until each of the pedicle screws is in a desired position with respect to the spinal rod; and   securing each pedicle screw to the spinal rod with a set screw.   
     
     
       2. The method of  claim 1 , wherein the force applying device further includes a neutral configuration and the second hook member includes a switch assembly having a first, a second, and a third position, each position corresponding to a configuration of the force applying device. 
     
     
       3. The method of  claim 1 , wherein the first and second hook members each include a hook portion, each hook portion having a compressing hook and a distracting hook. 
     
     
       4. The method of  claim 1 , wherein the fulcrum is attached to a gripping portion of each outer member. 
     
     
       5. The method of  claim 1 , wherein the step of advancing further includes attaching an anti-torque handle to a distal segment of each outer member and attaching a turning handle to a proximal segment of each outer member. 
     
     
       6. The method of  claim 1 , wherein the method further includes the step of inserting at least one set screw through an inner member and at least partially locking the rod to at least one of the pedicle screws before the step of manipulating the each outer member. 
     
     
       7. A method for manipulating vertebrae comprising:
 securing a first elongate member to a first pedicle screw that is secured in a first vertebra;   securing a second elongate member to a second pedicle screw that is secured in a second vertebra; and   manipulating the first and second elongate members with a force applying device until the first and second pedicle screws are in a desired position, the force applying device having first and second hook members, each hook member having a distracting hook and a compressing hook.   
     
     
       8. The method according of  claim 7 , wherein manipulating the first and second elongate members with the force applying device includes positioning the first and second elongate members between the first and second hook members of the force applying device to compress the first and second elongate members towards one another. 
     
     
       9. The method according of  claim 7 , wherein manipulating the first and second elongate members with the force applying device includes positioning the first and second hook members of the force applying device between the first and second elongate members to distract the first and second elongate members away from one another. 
     
     
       10. The method according of  claim 7 , further comprising positioning a fulcrum over a distal end of each of the first and second elongate members before manipulating the first and second elongate members with the force applying device. 
     
     
       11. The method according to  claim 10 , wherein manipulating the elongate members with the force applying device includes engaging the first elongate member with the first hook member between the fulcrum and the pedicle screw and engaging the second elongate member with the second hook member between the fulcrum and the pedicle screw. 
     
     
       12. The method according of  claim 7 , further comprising:
 reducing a spinal rod into a head of the first pedicle screw with the first elongate member; and   reducing the spinal rod into a head of the second pedicle screw with the second elongate member.   
     
     
       13. A method for manipulating vertebrae comprising:
 securing a first elongate member to a first pedicle screw that is secured in a first vertebra;   securing a second elongate member to a second pedicle screw that is secured in a second vertebra; and   manipulating the first and second elongate members with a force applying device until the first and second pedicle screws are in a desired position, the force applying device having a compressing configuration, a distracting configuration, and a neutral configuration and including two hook members, at least one of the two hook members including switch assembly for selecting a respective one of the compressing, distracting, and neutral configurations, the switch assembly defining detents which each correspond to a respective one of the compressing, distracting, and neutral configurations of the force applying device.   
     
     
       14. A compression/distraction system, comprising:
 a pair of elongate members, including:
 a first elongate member having a distal end removably securable to a first bone anchor such that the first elongate member extends away from the first bone anchor along a first longitudinal axis, the first elongate member having a lateral outer surface extending along the first longitudinal axis; 
 a second elongate member having a distal end removably securable to a second bone anchor such that the second elongate member extends away from the second bone anchor along a second longitudinal axis, the second elongate member having a lateral outer surface extending along the second longitudinal axis; and 
   a force applying device, including:
 a body portion defining a compression/distraction dimension; 
 a first engagement member having a longitudinal dimension projecting outwardly from the body portion transverse to the compression/distraction dimension, the first engagement member having an inner side and an outer side extending along the longitudinal dimension of the first engagement member on opposing sides of the first engagement member in the compression/distraction dimension; and 
 a second engagement member having a longitudinal dimension projecting outwardly from the body portion transverse to the compression/distraction dimension, the second engagement member having an inner side and an outer side extending along the longitudinal dimension of the second engagement member on opposing sides of the second engagement member in the compression/distraction dimension, the inner sides of the first and second engagement members facing towards one another, and the outer sides of the first and second engagement members facing away from one another; 
   wherein the first and second engagement members are movable relative to one another along the compression/distraction dimension to change a distance defined between the first and second engagement members;
 wherein the first and second engagement members of the force applying device are selectively engageable to the pair of elongate members such that the force applying device can apply compression and distraction forces to the first and second bone anchors via the respective first and second elongate members, the force applying device being engageable to the pair of elongate members in a compressing configuration for applying the compression forces and in a distracting configuration for applying the distraction forces; wherein the inner sides of the first and second engagement members are configured to engage the lateral outer surfaces of the respective first and second elongate members with the pair of elongate members positioned between the first and second engagement members in the compressing configuration; and wherein the outer sides of the first and second engagement members are configured to engage the lateral outer surfaces of the respective first and second elongate members with the first and second engagement members positioned between the pair of elongate members in the distracting configuration.  
   
     
     
       15. The compression/distraction system of claim 14, wherein each of the first and second engagement members includes a first receiver and a second receiver, the first receiver of each of the first and second engagement members being configured to receive a respective one of the pair of elongate members in the compressing configuration, and the second receiver of each of the first and second engagement members being configured to receive a respective one of the pair of elongate members in the distracting configuration.  
     
     
       16. The compression/distraction system of claim 15, wherein the first receiver of each one of the first and second engagement members is a respective first concave portion facing towards the other of the first and second engagement members, and wherein the second receiver of each one of the first and second engagement members is a respective second concave portion facing away from the other of the first and second engagement members.  
     
     
       17. The compression/distraction system of claim 14, wherein the body portion includes a track along which the second engagement member is movable along the longitudinal dimension.  
     
     
       18. The compression/distraction system of claim 17, wherein the second engagement member is movable along the longitudinal dimension by rotation of a toothed pinion to advance the pinion along a set of teeth positioned along at least a portion of the track.  
     
     
       19. The compression/distraction system of claim 14, wherein the force applying device is transitionable between the compressing configuration and the distracting configuration by moving a switch assembly between a first position and a second position, respectively.  
     
     
       20. The compression/distraction system of claim 19, wherein the switch assembly is movable to a third position corresponding to a neutral configuration of the force applying device, the neutral configuration permitting the second engagement member to freely move along the longitudinal dimension both towards and away from the first engagement member.  
     
     
       21. The compression/distraction system of claim 20, wherein the first and second engagement members are respective first and second hook members, the second hook member including ball detents each corresponding to a respective one of the first, second, and third positions of the switch assembly.  
     
     
       22. The compression/distraction system of claim 19, wherein moving the switch assembly between the first position and the second position causes a pawl to rotate between a first angular position and a second angular position, respectively, the pawl engaging a set of teeth of the force applying device in both the first and second angular positions, such that the engagement between the pawl and the set of teeth in the first angular position prevents relative movement of the first and second engagement members away from one another along the longitudinal dimension, and such that the engagement between the pawl and the set of teeth in the second angular position prevents relative movement of the first and second engagement members towards one another along the longitudinal dimension.  
     
     
       23. A force applying device for a compression/distraction system, comprising:
 a first engagement member;   a second engagement member;   a body portion coupling the first and second engagement members together along a longitudinal dimension; and   a switch assembly;   wherein the first and second engagement members are movable relative to one another along the longitudinal dimension to change a distance defined between the first and second engagement members;   wherein the first and second engagement members of the force applying device are selectively engageable to a pair of elongate members each securable to a respective bone anchor such that the force applying device can apply compression and distraction forces to the bone anchors via the elongate members; wherein the force applying device has a compressing configuration and a distracting configuration, the compressing configuration restraining relative movement of the first and second engagement members away from one another along the longitudinal dimension while permitting relative movement of the first and second engagement members towards one another along the longitudinal dimension, and the distracting configuration restraining relative movement of the first and second engagement members towards one another along the longitudinal dimension while permitting relative movement of the first and second engagement members away from one another along the longitudinal dimension; and wherein the force applying device is transitionable between the compressing and distracting configurations by moving the switch assembly between a first position and a second position, respectively.    
     
     
       24. The force applying device of claim 23, wherein each of the first and second engagement members includes a first receiver and a second receiver, the first receiver of each of the first and second engagement members being configured to receive a respective one of the pair of elongate members in the compressing configuration, and the second receiver of each of the first and second engagement members being configured to receive a respective one of the pair of elongate members in the distracting configuration.  
     
     
       25. The force applying device of claim 24, wherein the first receiver of each one of the first and second engagement members is a respective first concave portion facing towards the other of the first and second engagement members, and wherein the second receiver of each one of the first and second engagement members is a respective second concave portion facing away from the other of the first and second engagement members.  
     
     
       26. The force applying device of claim 23, wherein the body portion includes a track along which the second engagement member is movable along the longitudinal dimension.  
     
     
       27. The force applying device of claim 26, wherein the second engagement member is movable along the longitudinal dimension by rotation of a toothed pinion to advance the pinion along a set of teeth positioned along at least a portion of the track.  
     
     
       28. The force applying device of claim 23, wherein the switch assembly is movable to a third position corresponding to a neutral configuration of the force applying device, the neutral configuration permitting the second engagement member to freely move along the longitudinal dimension both towards and away from the first engagement member.  
     
     
       29. The force applying device of claim 28, wherein the first and second engagement members are respective first and second hook members, the second hook member including ball detents each corresponding to a respective one of the first, second, and third positions of the switch assembly.  
     
     
       30. The force applying device of claim 23, wherein moving the switch assembly between the first position and the second position causes a pawl to rotate between a first angular position and a second angular position, respectively, the pawl engaging a set of teeth of the force applying device in both the first and second angular positions, such that the engagement between the pawl and the set of teeth in the first angular position prevents relative movement of the first and second engagement members away from one another along the longitudinal dimension, and such that the engagement between the pawl and the set of teeth in the second angular position prevents relative movement of the first and second engagement members towards one another along the longitudinal dimension.  
     
     
       31. The force applying device of claim 23, wherein the first and second engagement members are configured to engage the pair of elongate members with the elongate members positioned between the first and second engagement members in the compressing configuration; and wherein the first and second engagement members are configured to engage the pair of elongate members with the first and second engagement members positioned between the elongate members in the distracting configuration.  
     
     
       32. A force applying device for a compression/distraction system, comprising:
 a first engagement member having a portion including a distracting hook and a compressing hook;   a second engagement member having a portion including a distracting hook and a compressing hook; and   a body portion coupling the first and second engagement members together along a longitudinal dimension;   wherein the first and second engagement members are movable relative to one another along the longitudinal dimension to change a distance defined between the first and second engagement members; and   wherein the first and second engagement members of the force applying device are selectively engageable to a pair of elongate members each securable to a respective bone anchor such that the force applying device can apply compression and distraction forces to the bone anchors via the elongate members, the force applying device being engageable to the pair of elongate members in a compressing configuration for applying the compression forces and in a distracting configuration for applying the distraction forces.    
     
     
       33. The force applying device of claim 32, wherein the compressing hook of each of the first and second engagement members is configured to receive a respective one of the pair of elongate members in the compressing configuration, and wherein the distracting hook of each of the first and second engagement members is configured to receive a respective one of the pair of elongate members in the distracting configuration.  
     
     
       34. The force applying device of claim 32, wherein the compressing hook of each one of the first and second engagement members includes a respective first concave portion facing towards the other of the first and second engagement members, and wherein the distracting hook of each one of the first and second engagement members includes a respective second concave portion facing away from the other of the first and second engagement members.