Tightening device for spine surgery

Abstract

A device for spinal surgery that may be used for tightening a locking cap onto at least a portion of a pedicle screw. The device may include a torque-generating body having a proximal end and an opposing distal end and a drive shaft rotatably driven by the torque-generating body. A proximal end of the drive shaft may be operatively engaged to the distal end of the torque-generating body and an opposing distal end of the drive shaft may engage at least a portion of one of the locking cap and the pedicle screw. An anti-torque device is provided that has an elongated and generally hollow member defining a longitudinal axis. The member has a proximal end and an opposing distal end, where the proximal end of the anti-torque device may be fixed from rotating relative to at least a portion of the torque-generating body and the distal end may be fixed from rotating relative to a spine rod or a pedicle screw.

1 . A system for tightening a locking cap onto at least a portion of a pedicle screw during spinal surgery, the system comprising:
 a torque-generating body including an elongated shaft having a proximal end and an opposing distal end and defining a longitudinal axis extending therebetween, the distal end of the elongated shaft coupled to a handle;   a drive shaft rotatably driven by the torque-generating body, the drive shaft having a proximal end, an opposing distal end and a longitudinal axis extending therebetween, the proximal end of the drive shaft being operatively engaged to the distal end of the torque-generating body such that the longitudinal axis of the torque-generating body extends in a direction away from a longitudinal axis of a drive shaft, the opposing distal end of the drive shaft engaging at least a portion of one of a locking cap and the pedicle screw; and   an anti-torque device comprised of an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end, the proximal end of the anti-torque device being fixed from rotating relative to at least a portion of the torque-generating body,   wherein the drive shaft is operatively engaged with the torque-generating body such that rotational movement of the elongated shaft about the longitudinal axis of the torque-generating body translates into rotational movement of the drive shaft about the longitudinal axis of the drive shaft.   
     
     
         2 . The system of  claim 1 , wherein the distal end of the anti-torque device is fixed from rotating relative to at least a portion of one of the pedicle screw, the locking cap and a fixation rod. 
     
     
         3 . The system of  claim 1 , wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque T L  generated by the torque-generating body and an opposite reaction torque T R  generated by the anti-torque device. 
     
     
         4 . The system of  claim 3 , wherein the torque T L  generated by the drive shaft of the torque-generating body is provided to one of the locking cap and the pedicle screw, and the opposite reaction torque T R  generated by the anti-torque device is provided to one of the locking cap, the pedicle screw and a fixation rod. 
     
     
         5 . The system of  claim 1 , wherein the torque-generating body is one of a motorized power tool, a pressurized fluid or a hand-actuated screwdriver. 
     
     
         6 . The system of  claim 1 , wherein the anti-torque device is removably attached to the torque-generating body. 
     
     
         7 . The system of  claim 1 , wherein the proximal end of the anti-torque device may selectively engage at least a portion of one or more generally unique distal portions of the torque-generating body. 
     
     
         8 . The system of  claim 7 , wherein the proximal end of anti-torque device frictionally engages the distal portion of the anti-torque device. 
     
     
         9 . The system of  claim 7 , wherein a projection of the proximal end of anti-torque device engages a groove of the distal portion of the anti-torque device. 
     
     
         10 . The system of  claim 1 , wherein the anti-torque device further comprises a torque limiting mechanism that is connected to one of the torque-generating body. 
     
     
         11 . The system of  claim 10 , further comprising a gearbox that includes a first spur gear and a second spur gear, wherein the first spur gear engages the second spur gear, and wherein the second spur gear receives the drive shaft. 
     
     
         12 . The system of  claim 11 , wherein a gear ratio of the gearbox is between 2-to-1 and 10-to-1. 
     
     
         13 . The system of  claim 11 , wherein the gearbox increases the input torque applied by the torque-generating body. 
     
     
         14 . The system of  claim 11 , wherein the distal end of torque-generating body engages a notched shaft that is connected to a first gear, wherein the first gear drives the first spur gear. 
     
     
         15 . The system of  claim 1 , wherein the anti-torque device comprises radially spaced-apart archways that extend radially inwardly from the distal end of the anti-torque device. 
     
     
         16 . The system of  claim 15 , wherein a portion of one of the archways engages at least a portion of a fixation rod to maintain the distal end of the anti-torque device stationary. 
     
     
         17 . The system of  claim 1 , wherein the torque-generating body is connected to a worm gear by a shaft, and wherein rotation of the torque-generating body rotates the worm gear to turn the drive shaft. 
     
     
         18 . The system of  claim 1 , wherein the drive shaft comprises an outer sleeve that encloses a spring, wherein a distal portion of the outer sleeve is slidable along an axis of the drive shaft and is supported by the spring, and wherein the distal portion of the outer sleeve is rotationally engaged with the drive shaft. 
     
     
         19 . The system of  claim 1 , wherein a proximal end of the anti-torque device slidably engages the distal end of the torque-generating body. 
     
     
         20 . (canceled) 
     
     
         21 . An anti-torque device for spinal surgery comprising:
 an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end,   wherein the proximal end is fixed from rotating relative to a portion of a torque-generating body, and   wherein the distal end is fixed from rotating relative to at least a portion of one of a pedicle screw, a locking cap and a fixation rod.   
     
     
         22 . The device of  claim 21 , further comprising:
 a drive shaft rotatably driven by the torque-generating body, a proximal end of the drive shaft being operatively engaged to the distal end of the torque-generating body and an opposing distal end of the drive shaft engaging at least a portion of one of the locking cap and the pedicle screw.   
     
     
         23 . The device of  claim 22 , wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque T L  and an opposite reaction torque T R , and wherein the torque T L  generated by the drive shaft of the torque-generating body is provided to one of the treaded cap and the pedicle screw, and the opposite reaction torque T R  generated by the anti-torque device is provided to one of the treaded cap, the pedicle screw and the fixation rod. 
     
     
         24 . The device of  claim 21 , wherein the anti-torque device is removably attached to the torque-generating body. 
     
     
         25 . The device of  claim 24 , wherein a proximal end of the anti-torque device slidably engages the distal end of the torque-generating body. 
     
     
         26 . The device of  claim 25 , wherein the proximal end of the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body. 
     
     
         27 . The device of  claim 21 , wherein the anti-torque device further comprises a torque limiting mechanism that is connected to the a torque-generating body and to a gearbox, wherein the gearbox has a first spur gear that engages a second spur gear, and wherein the second spur gear receives a drive shaft that engages at least a portion of one of the locking cap and pedicle screw. 
     
     
         28 . The device of  claim 27 , wherein rotation of the gearbox by the torque limiting mechanism rotates the drive shaft and increases the torque applied by the torque-generating body. 
     
     
         29 . The device of  claim 21 , wherein the anti-torque device comprises radially spaced-apart archways that engage at least a portion of the fixation rod to maintain the distal end of the anti-torque device stationary. 
     
     
         30 . A method of tightening a locking cap onto a pedicle screw during spine surgery, the method comprising:
 providing a torque-generating body having a drive shaft rotatably attached thereto;   engaging at least a portion of a drive shaft with a locking cap;   rotatably fixedly attaching a first end of an anti-torque device to at least a portion of the torque-generating body;   rotatably fixedly attaching a second end of the anti-torque device to at least a portion of one of a pedicle screw, the locking cap and a fixation rod; and   rotating the drive shaft to apply a locking torque to one of the locking cap and pedicle screw, thereby generating an equal and opposite reaction torque to one of the pedicle screw, the locking cap and the fixation rod.   
     
     
         31 . The method of  claim 30 , further comprising:
 rotating the torque-generating body to create a generally balanced reaction between a locking torque T L  generated by rotation of the torque-generating body and a generally equal and opposite reaction torque T R  generated by the anti-torque device.   
     
     
         32 . The method of  claim 30 , further comprising fixing a proximal end of the anti-torque device from rotating relative to at least a portion of the torque-generating body so as to not rotate with the drive shaft. 
     
     
         33 . The method of  claim 32 , wherein fixing the proximal end of the anti-torque device comprises slidably engaging the proximal end of the anti-torque device with the distal end of the torque-generating body. 
     
     
         34 . The method of  claim 33 , wherein the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body. 
     
     
         35 . The method of  claim 30 , further providing a gearbox to increase the input torque provided by the torque-generating body applied to the drive shaft. 
     
     
         36 . The method of  claim 30 , further comprising:
 providing radially spaced-apart archways at the second end of the anti-torque device; and   engaging at least a portion of the fixation rod with the archways to maintain the anti-torque device stationary.   
     
     
         37 . A surgical device, comprising:
 a torque-generating body having a proximal end and an opposing distal end;   a gearbox that receives an input torque from the torque-generating body and provides an increased output torque to a drive shaft, a proximal end of the drive shaft being operatively engaged to the gearbox and a opposing distal end of the drive shaft engaging at least a portion of one of a locking cap and a pedicle screw; and   an anti-torque device comprised of an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end, the proximal end of the anti-torque device being slidably engaged to a housing of the gearbox and fixed from rotating relative to at least a portion of the torque-generating body.   
     
     
         38 . The device of  claim 37 , wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque T L  and a generally equal and opposite reaction torque T R  generated by the anti-torque device. 
     
     
         39 . The device of  claim 38 , wherein the torque T L  generated by the drive shaft of the torque-generating body is on one of the treaded cap and the pedicle screw, and the opposite reaction torque T R  generated by the anti-torque device is on one of the treaded cap, the pedicle screw and a fixation rod. 
     
     
         40 . The device of  claim 37 , wherein the proximal end of the anti-torque device is rotatably fixedly attached to and fixed from rotating relative to at least a portion of the torque-generating body so as to not rotate with the drive shaft. 
     
     
         41 . The device of  claim 37 , wherein the anti-torque device further comprises a torque limiting mechanism that is connected to the a torque-generating body and to a first spur gear, and wherein the first spur gear engages a second spur gear that receives the drive shaft. 
     
     
         42 . The device of  claim 41 , wherein the distal end of torque-generating body engages a notched shaft that is connected to a first gear, wherein the first gear drives the first spur gear. 
     
     
         43 . The device of  claim 37 , wherein a gear ratio of the gearbox is between 2-to-1 and 10-to-1. 
     
     
         44 . The device of  claim 43 , wherein the gearbox increases the input torque applied by the torque-generating body. 
     
     
         45 . The device of  claim 37 , wherein the proximal end of the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body.