Patent Abstract:
A spinal alignment correction system ( 1 ) has a posted lumbar pedicle screw called a MAC Pin ( 10 ) which has an elongated shaft ( 11 ) and a rod coupler assembly ( 20 ) and a cannulated tower ( 40 ). The elongated shaft ( 11 ) has an inner pedicle screw portion ( 12 ) with pedicle threads ( 12 A), an outer second thread portion ( 14 ) with second threads ( 14 A) and a transition or intermediate portion ( 16 ) disposed between the pedicle screw portion ( 12 ) and the second thread portion ( 14 ). The cannulated tower ( 40 ) when mounted over said elongated shaft ( 11 ) abuts said coupler ( 20 ) along an outer cam surface and further tightening rotation of the cannulated tower ( 40 ) causes outward movement of the elongated shaft ( 11 ). The system ( 1 ) allows for a controlled alignment correction of malaligned vertebral bodies using a number of methods used to correct a variety of indications.

Full Description:
RELATED APPLICATIONS 
       [0001]    The present invention is a division of co-pending U.S. application Ser. No. 14/220,830 entitled, “Spinal Alignment Correction System And Methods Of Use” filed on Mar. 20, 2014. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention is directed to a device for use in correcting various lumbar and thoracic spinal maladies including reduction of Spondylolisthesis and various other corrective procedures and surgical treatment including scoliosis, trauma and other malalignments of the spine. 
       BACKGROUND OF THE INVENTION 
       [0003]    A recently published paper in  The Journal of Bone and Joint Surgery Incorporated  2014; 96: 53-8 entitled “Evidence—Based Surgical Management of Spondylolisthesis Reduction Or Arthrodesis In Situ” reported “The role of reduction in the operative management of spondylolisthesis is controversial because of its potential complications, including neurologic deficits, prolonged operative time, and loss of reduction.” This study reported “The decision to correct high-grade slippage defects by reduction is still a controversial one. In an attempt to determine which patients should be treated with reduction, some authors have investigated the relationship between sagittal spinal parameters and pelvic morphology and orientation. Patients with high-grade spondylolisthesis could be classified on the basis of the orientation of the pelvis as having a “balanced” or unbalanced” pelvis. The balanced pelvis type of spondylolisthesis includes patients with low pelvic tilt and high sacral slope, whereas the unbalanced type includes patients with a retroverted pelvis having a high pelvic tilt and low sacral slope. On the basis of this classification, some authors suggest reduction of the deformity, restoring the spinopelvic balance, only in patients with an unbalanced pelvis, whereas arthrodesis in situ without correction would be preferred in patients with a balanced pelvis. Although reduction can potentially result in complications, complication rates in the present analysis did not differ between the reduction and arthrodesis in situ groups. On the other hand, reduction of a high-grade spondylolisthesis would improve overall spine biomechanics by correcting the local kyphotic deformity and reducing the vertebral slippage. We manage patients with high-grade spondylolisthesis by performing reduction under intraoperative neurophysiologic monitoring such as SSEPs combined with spontaneous electromyography. We usually perform a posterolateral or circumferential instrumented arthrodesis. In conclusion, we found no definite benefit of reduction over arthrodesis in situ except for a significantly lower rate of pseudarthrosis. Further adequately powered randomized trials with appropriate subjective and objective outcome measures are required to establish evidence-based surgical management of high-grade spondylolisthesis.” 
         [0004]    The current surgical practice for low to medium grade spondylolisthesis reduction employs the use of pedicle screws with connective rods. Wherein the surgeon measures the amount of reduction required to realign the vertebrae and then uses the connecting rod to pull the upper vertebral body back causing a lever type action and placing the rod fastener into the tulip connection to fix the connections. As one can appreciate, this current best practice is at best an estimate of final reduction, due in part to a lack of control; the final results are typically a compromised approximation, but not a true alignment. Often this procedure of moving the adjacent vertebral bodies closer to alignment is a sufficient improvement to help the patient; however, this inability of the surgeon to precisely control the reduction is far from ideal. Furthermore, if the reduction achieved is less than satisfactory, the surgeon must start over loosening the rod and repositioning the pedicle screws, thus extending the surgical procedure. 
         [0005]    The ideal reduction procedure would allow the surgeon to accomplish the reduction by controlling the movement in a consistent reliable and adjustable fashion so the exact optimal alignment is always achieved in the absence of predicting the preferred location, but rather controlling the movement to that exact location. Most importantly, this ability must occur in a timely fashion without unduly extending the surgical procedure. 
         [0006]    The present invention as described herein accomplishes all these objectives and does so in typically less than 5 minutes added surgical time, most typically less than 4 minutes. Most advantageously, the system of the present invention is so accurate and reliable it virtually eliminates any need to redo the steps as there is no estimation made as to final placement, but rather a controlled movement to alignment which is fixed by the independent adjustment capability of the device in the hands of the surgeon aided by fluoroscopic vision. 
         [0007]    These and other features of the system and its components afford new techniques in lumbar and thoracic spine surgery for use in a variety of indications as explained hereafter and shown in the attached drawings. 
       SUMMARY OF THE INVENTION 
       [0008]    A method of treating and correcting a spinal misalignment is summarized in the steps: after exposing the spine and preparing it for instrumentation; Step 1—place MAC Pins bilaterally into the affected vertebral body, then one places standard top loading tulip pedicle screws into the vertebral body below. The listhesed segment such that two vertebral bodies are instrumented. Next a contoured rod is chosen based on the distance between the macpin and the pedicle screw discovered interoperatively. This rod is secured in an opening in the caudal edge of the coupler with a nut in the contoured position. The coupler is then slipped over the MAC Pin down into the surgical wound with the caudal edge of the rod falling into the top loading tulip of the pedicle screw below. At this point, the end cap is placed on the standard pedicle screw in the tulip and is tightened into position locking rods in the bilateral pedicle screws into a monoaxial and fixed relationship with regard to the instrumented vertebral bodies, the pedicle screws and the rods. The next step is to place the cannulated reduction tower over the macpin and through clockwise rotation of the reduction tower the listhesis is reduced in a slow, controlled and accurate method until the interoperative fluoroscope indicates a satisfactory reduction thus appropriate sagittal alignment. At this point, the second nut on the coupler is tightened with a wrench and this locks the entire construct into a rigid position therefore securing the spondylolisthesis reduction in place. The outer cannulated tower is then removed and the MAC Pins are sheared off flush with the coupler. It is at this point a laminectomy or decompression of the neural elements can be performed if so desired. Following the laminotomy, an interbody preparation fusion and graft placement can then take place. An alternative method would be to close the surgical wound and perform an anterior lumbar interbody fusion or a lateral transpsoas interbody fusion according to the pathology, indications and surgeon&#39;s surgical strategy. 
         [0009]    A spinal alignment correction system has an elongated shaft and a rod coupler assembly. The elongated shaft has an inner pedicle screw portion with pedicle threads, an outer second thread portion with second threads and a transition or intermediate portion disposed between the pedicle screw portion and the second thread portion. The rod coupler has a pair of openings, a first opening for passing over the elongated shaft and being movable lengthwise within the transition or intermediate portion and a second opening for receiving a rod. The rod coupler is rotationally movable about said shaft. The spinal alignment correction system further has a cannulated tower. The cannulated tower has a longitudinally extending opening having internal threads complimentary to said second thread of said elongated shaft. The cannulated tower when mounted over said elongated shaft abuts said coupler along an outer cam surface and further tightening rotation of the cannulated tower causes outward movement of the elongated shaft. The spinal alignment correction system further has a handle removably attached to the cannulated tower to facilitate rotation of the cannulated tower. The spinal alignment correction system further has a rod fastener, said rod fastener when attached to said rod connector locks a rod securely fixed in the rod receiving opening. The spinal alignment correction system further has a washer and a locking nut for attachment onto the coupler and abuttingly locking said washer against said coupler. 
         [0010]    The spinal alignment correction system further has a rod, a rod fastener and a pedicle screw with rod receiving connection. The pedicle screw when affixed to a lower vertebral body has the rod extend to the second rod receiving opening of the rod coupler positioned over the elongated shaft affixed to an upper vertebral body, when the rod is at one end is placed in said rod receiving connection of the pedicle screw and fixed by said fastener, the opposite rod is placed in the second rod opening of said coupler and fixed to said coupler after a desired vertebral alignment is achieved. The elongated shaft preferably is made of titanium. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0012]      FIG. 1  is a perspective view of the system or device of the present invention. 
           [0013]      FIG. 1A  is a view of the system of  FIG. 1  installed in a spine segment. 
           [0014]      FIG. 2  is an exploded view of the present invention of the system shown in  FIG. 1 . 
           [0015]      FIG. 3  is a perspective view of the posted pedicle screw or MAC Pin. 
           [0016]      FIG. 3A  a view of the MAC Pin with rod coupler assembly. 
           [0017]      FIG. 4  is an exploded view of the rod coupler. 
           [0018]      FIG. 4A  is an exploded side view of the rod coupler. 
           [0019]      FIG. 4B  is an as assembled view of the coupler. 
           [0020]      FIG. 4C  shows an additional view of an alternative multiaxial or polyaxial coupler providing an ability to slightly tilt angle the MAC Pin in any direction to facilitate installation of the system. 
           [0021]      FIG. 4D  is the alternative coupler of  FIG. 4C  shown in a perspective view assembled. 
           [0022]      FIG. 4E  is a side view of the coupler of  4 D assembled. 
           [0023]      FIG. 4F  is an alternative embodiment of the present invention shown in an exploded perspective view illustration of the MAC Pin made as a multi-piece posted lumbar pedicle screw and illustrating a medial offset or lateral offset coupler design. 
           [0024]      FIG. 4G  is a side view of the alternative embodiment. 
           [0025]      FIG. 4H  is a perspective view. 
           [0026]      FIG. 4I  is an assembled view. 
           [0027]      FIG. 5  is a side view of the cannulated tower. 
           [0028]      FIG. 5A  is a cross sectional view of the cannulated tower. 
           [0029]      FIG. 6  is a view of the handle for use with the cannulated tower. 
           [0030]      FIG. 6A  is a cross section of the handle. 
           [0031]      FIG. 7  is a view of the wrenches shown above MAC Pins and cannulated towers of the system for final nut tightening. 
           [0032]      FIG. 7A  shows the wrenches in place over the system to provide final nut tightening to fix the MAC Pin to the coupler. 
           [0033]      FIGS. 8A-8J  are various views of spines having the system of the present invention used showing the various steps employed. 
           [0034]      FIG. 9A  is a side view illustrating a malaligned spine and a use of the system showing the reduction direction as the handle is rotated. 
           [0035]      FIG. 9B  shows the corrected spine segment of  FIG. 9A . 
           [0036]      FIG. 10A  shows a scoliosis treatment and how the system can be used to also provide a rotational correction of a vertebral body. 
           [0037]      FIG. 10B  is a view showing the correction result provided to the spine segment of  FIG. 10A . 
           [0038]      FIG. 11  is a view of a cannulated MAC Pin for use with a K-wire in a percutaneous procedure. 
           [0039]      FIG. 12A  is a perspective view of an insertion tool, inserting a stabilizer rod into a bone screw system with leg extensions for use in a percutaneous procedure. 
           [0040]      FIG. 12B  is a perspective view of the insertion tool of  FIG. 12A , showing the insertion tool using the connector as a fulcrum to maneuver the stabilizer rod into position. 
           [0041]      FIG. 12C  is a perspective view of the insertion tool of  FIG. 12A , showing the insertion too using the connector as a fulcrum to further maneuver the stabilizer rod into position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0042]    The following description is best understood by reference to the attached drawings depicting one embodiment of the present invention. With reference to  FIGS. 1 ,  1 A and  2 . 
         [0043]    The device or spinal alignment system  1  is shown as described has a double threaded post lumbar pedicle screw  10  hereinafter also referred to as a Maximum Alignment Correction Pin (MAC Pin) that is placed in the vertebral body  201  and coupled with a special screw rod coupler or coupler assemblies  20  and that adjoins the posted screw  10  to a rod  100  connected into a lower vertebral body  202  of a particular segment of the spine  200 . The posted screw  10  is attached to the rod  100  and the other end of the rod  100  attached to a typical pedicle screw  110  placed in the vertebral body  202  below. The device or system  1  will include a double threaded post lumbar/thoracic pedicle screw thread end portion  12  on the screw  10  as well as a coupler  20  and there is also a technique for using this implanted device or system  1 . 
         [0044]    As shown in  FIGS. 3 and 3   a , this posted pedicle screw  10  has a one piece shaft  11  with a double threaded pedicle screw thread  12  of a typical pedicle screw. The thread  12  extends from a leading tip  11 A to a length at least 40 mm, preferably of about 50-55 mm in length up the shaft  11 , thereafter the posted screw  10  has a smooth shaft portion  16  between two threaded portions. The pedicle threads of the screw  10  are in the range of 5.0 to 8.0 mm in size, more typically between 5.5 and 7.5 mm and have a self-tapping feature as shown at end  11 A. A second thread  14  at the other end of the shaft  11  of the screw  10  of the screw is used for the actual reduction or translation technique. The outer end  11 B of the second screw portion  14  that will be sticking out of the spine  200  may have a squared off or flat feature that will be able to connect to a handle or wrench that will allow the posted pedicle screw  10  to be installed into the vertebral bone  202 , independent of the the rod coupler  20 . This shafted post pedicle screw  10  is called the MAC Pin (Maximum Alignment Correction Pin). For the first time this pedicle screw  10  and coupler  20  enables the vertebral body  201  to be pulled back in the sagittal plane to be realigned with the other vertebral bodies  202  to establish perfect mechanical alignment, restore the mechanical alignment of the spine  200 , believed to be the best outcome for the patient. The coupler  20  enables the tip  11 B of the posted pedicle screw or the MAC Pin  10 , once the pedicle portion  12  of the MAC Pin  10  has been placed within the vertebral body  201  of the lumbar spine  200 , to be pulled back. That threaded portion  14  will be used to pull the vertebrae  201  back 35-50 or 65 mm. The coupler  20  is slipped over outer the tip  11 B of the MAC Pin  10 , the coupler  20  as an assembly, but untightened, falls into the spine interoperatively into the smooth shaft portion  16  of the MAC Pin  10  between the two threaded  12  and  14  areas of the MAC Pin  10 . The coupler  20  is attached to an end of a contoured rod  100  which when placed down over the MAC Pin  10 , the opposite end of that rod falls into the top of aa top loading tulip  120  of the tulip headed pedicle screw  110  in the vertebral body  202  below. When the coupler  20  fixed to the rod  100  is placed within the pedicle screw  110  this enables not only translation again also distraction or compression of the motion segment  202  between the two vertebral bodies  201 ,  202 . Once this assembly is accomplished, the technique can begin. 
         [0045]    With referenced to  FIGS. 3A ,  4 ,  4 A and  4 B the rod coupler assembly  20  is shown, the coupler  20  has two holes  21 ,  22 , one hole  21  is able to slip over the posted pedicle screw or MAC Pin  10  and then the other hole  22  will allow the contoured rod  100  to fit within it and then prior to placing the coupler  20  and rod  100  over the posted pedicle screw or MAC Pin  10  the surgeon will lock the rod  100  by choosing various lengths of rods according to what is discovered as needed interoperatively with the 5.5 diameter rod  100 , the rod  100  will slip into the caudal edge of the coupler  20 . Once the rod  100  is slipped into the caudal edge, there is a separate nut or set screw  102  and tightener that tightens this rod  100  in place into the threaded opening  103  of the coupler  20 . 
         [0046]    As shown in  FIGS. 4 ,  4 A and  4 B, the rod coupler assembly  20  has a coupler body  24  which has the openings  21  and  22  for receiving and holding the MAC Pin  10  and rod  100  respectively. At the bottom of  FIG. 4  is a hollow shaft holding coupling  26  with a threaded end  98  and an opposite rounded or spherical end  99  with a plurality of slots  97  to allow the end  27  to grip the MAC Pin  10  when the coupler assembly nut  60  is tightened against the washer  62  and the teeth  25  serrated sidewalls  23 . The washer  62  having complimentary serrated teeth  65  that interlock as the nut  60  threads onto the threads  98  of the shaft holding coupling  90 . Initially, the entire coupling assembly  20  is connected, but loosely so the coupling can slide freely over the MAC Pin  10  and move angularly about the smooth shaft portion  16 . Only when the proper vertebral body alignment is achieved by the use of the cannulated tower  40  and the handle  50  is the nut  60  tightened locking the coupler  20  onto the MAC Pin  10  fixing its position. As noted, all the parts aligned with opening  21  have openings allowing the MAC Pin  10  to pass as shown. The shaft holding coupling mechanism  90  provides for limited angular motion of the MAC Pin  10 . Nevertheless, this ability to tilt the assembly is beneficial to the installation of the instrumentation. As further illustrated, the system  1  further has a cannulated reduction tower or shaft  40  mounted over the MAC Pin  10  and resting on a nut  60  of the coupler assembly  20 . Above and removably affixed to the tower  40  is a handle  50  which is used to rotate the cannulated reduction tower  40  as the system  1  is employed to align the vertebral body  202  in the spine  200 . 
         [0047]    Once the rod  100  and coupler  20  are joined through this nut  102 , a fixed relationship is established between the rod  100  and coupler  20 . At that point, the other end, the cranial end, of the coupler  20  would then slip over the MAC Pin  10  until the coupler falls into the dorsal aspect of the bone of the vertebral body  201  which is the base of the lumbar pedicle and also at that point it will be positioned within the smooth shaft portion  16  of the MAC Pin  10 , the threaded pedicle portion  12  of the MAC Pin  10  would have been driven transpedicularly into the vertebral body  201  where whatever length has been chosen of the threaded pedicle portion  12  of the threads  12 A will be countersunk into the vertebral body and pedicle shaft. This can be anywhere from 35 mm up to 50-65 mm within the vertebral body  201 . At this point, sticking out of the posterior aspect of the pedicle and vertebral body  201  would be the MAC Pin  10 , the smooth shaft portion  16  and also the second thread portion  14  as well as the squared off tip  11 B. So when the coupler  20  slips over the post MAC Pin  10 , the coupler  20  is positioned within the smooth shaft portion  16  enabling it to more or less cam back and forth on the MAC Pin  10  so that a smooth frictionless relationship exists with the MAC Pin  10  and the rod. At this point again, simultaneously when the coupler  20  and the rod  100  are slipped over the MAC Pin  10 , the caudal of the 5.5 rod  100  would fall down into the opening of the tulip  120  the top loading tulip pedicle screw  110  and the vertebral body  201 . At that point, the end fastener cap  130  on the tulip  120  of the top loading pedicle screw  110  would be placed and the end cap  130  would be tightened after whatever distraction or compression is desired. Once the coupler  20  and the rod  100  slide down over the MAC Pin  10  and fall within the tulip  120 , the end cap  130  of the tulip  120  would then be placed. At this point, a distractor or a compressor can be utilized to distract between the MAC Pin  10  from the pedicle screw  110  once it achieves distraction of the this or the posterior neuroforamen, independently of the translation of the vertebral body  201  that follows this distraction. Once distraction or compression is accomplished, the end cap  130  and the posted pedicle screw  10  below would be tightened and then the rod  100  and the posted pedicle screw  10  relationship would become fixed. At that point the only motion that is still available between the MAC Pin  10  and the pedicle screw  110  below or at the rod  100  is the translation or the reduction of the spondylolisthesis. 
         [0048]    To visually appreciate the procedure, after the MAC Pins  10  have been inserted bilaterally, the surgeon would place the coupling assembly  20  over the MAC Pin  10  as shown in  FIGS. 8E-8G  and lock the connector rod  100  to the pedicle screw as discussed. Thereafter, the cannulated towers  40  and handles  50  would be placed over the MAC Pins  10  as shown in  FIGS. 8A-8D . At this point, the rod coupler assembly is assembled, but is loose sitting over the smooth shaft portion  16  free to allow the MAC Pin  10  to be retracted. As shown in  FIG. 8D , once the towers engage the second threads  14 A by rotation of the handle  50 , the MAC Pins  10  are retracted. The tower  40  abuts on the nut  60  which acts as a cam. Importantly, as the tower  40  rotates, the MAC Pin  10  does not rotate, but rather moves longitudinally in the direction of the handle rotation. In this way, the pedicle portion  12  does not change neither tightening nor loosening. This allows the vertebral body  202  to retract toward alignment. Once the desired alignment is achieved, the handle  50  can be removed and a wrench  70 , shown in  FIGS. 7 and 7A , can pass over the tower  40  to securely tighten the nut  60  fixing and locking the rod coupler  20  to the MAC Pin  10 . This occurs as the slots  97  at the end of the coupling mechanism  90  close about the shaft  11  at the smooth portion  16  of the MAC Pin  10 . Once locked in position, the wrench  70  is removed and the cannulated tower  40  is removed from its attachment to the exposed second threaded portion  14  of the MAC Pin  10 . Once removed, the surgeon cuts the MAC Pin  10  flush to the nut  60  of the rod coupler assembly  20  as shown in views  8 H- 8 J. 
         [0049]    In  FIGS. 9A and 9B  an exemplary procedure of a spinal segment  200  is shown with the system  1  installed and being turned to retract the spondylolisthesis of vertebral body  202  as the rod  100  is fixed to the lower vertebral body  201  at the pedicle screw  111 . Once alignment is achieved, the tower  40  is removed after the nut  60  is tightened, see  FIG. 9B . This is accomplished preferably using two MAC Pins  10  bilaterally as previously discussed in reference to  FIGS. 8A-8J . 
         [0050]    The next step would be slipping a cannulated tower  40 , shown in  FIG. 5  and cross section in  FIG. 5A , over the exposed outer tip  11 B of the MAC Pin  10  with a handle  50  on that cannulated tower  40 . The cannulated tower  40  has an inner threaded portion  42  that threads onto the second set of threads  14 A on the exposed MAC Pin  10 . At this point, the handle  50  on the cannulated tower  40  is rotated moving the tower  40  over that threaded portion  14  of the MAC Pin  10  and as you move the handle  50 , the cannulated tower  40  moves down the threads  14  until it abuts against the nut  2  of the coupler; the pedicle screw portion and rod relationship and begins to pull that vertebral body into a more aligned position such that the surgeon would be able to translate or reduce the spondylolisthesis anywhere between 1 mm up to 2-3 cm and this is a unique property of the system  10  in that no other system allows an independent translation and independent distraction and compression of the motion segment that is so accurate. Once you begin to translate the MAC Pin  10  on the coupler  20 , it allows complete independent and accuracy whether or not you need 1 mm of reduction or 3 cm of reduction. The surgeon is able to dial that in interoperatively and stop at whatever point he wants between that 0 to 3 cm. There is no guesswork, no estimation, the surgeon simply begins to dial in the amount of reduction he wants and by checking interoperative fluoroscope he can judge when the reduction is complete and therefore stop the process at that point. 
         [0051]    As shown in  FIG. 5 , the cannulated tower  40  has an end  40 A with flats  45  to receive the handle  50 . The tower  40 , as shown, further has a window opening  46  which allows the surgeon to see the MAC Pin  10  movement. A graduated scale  48  marked 10-60 increments of 10 mm is provided adjacent the window opening  46 . The handle  50 , shown in  FIGS. 6 and 6A , when placed onto the tower  40  has an opening  54  that allows the MAC Pin  10  to pass. The opening  52  receives the end  40 A and has flats  55  to compliment the flats  45  to rotationally fix the tower to the removable handle  50 . 
         [0052]    Another unique feature of this system is the fact that as the surgeon reduces the spondylolisthesis, let&#39;s say for example 2 cm, and for whatever reason perhaps the nerve begins to show signal of being pinched, he can then go back and translate the vertebral body  201  forward again back to say 1 or 1.5 cm. Essentially, this device  10  gives the surgeon complete control of an accurate reduction, distraction and rotation of the vertebral body  202  like no other product does. Once the translation or rotation has been performed through the MAC Pin  10  and the cannulated tower  40  and handle  50 , at that point a separate wrench  70  and nut  60  are placed over the cannulated tower  40  and the MAC Pin  10  being held in place. The surgeon, using the separate wrench  70 , tightens a nut  60  on the coupler  20 , this locks the relationship between the coupler  20  and MAC Pin  10  so that is now a fixed relationship and once that fixed relationship is achieved, then the reduction is complete and locked in. At that point, the wrench  70  comes off the cannulated tower  40  and then the cannulated tower  40  is removed from the MAC Pin  10  and then a MAC Pin cutter  80  fits over the exposed tip of the MAC Pin  10  and cuts the MAC Pin  10  flush with the coupler  20 . Now the procedure is completed with a fully distracted or compressed and reduced vertebral body  202  in the spondylolisthesis. At this point, every relationship between the MAC Pin  10 , the pedicle screw  110  and the rod  100  are locked down and fixed ensuring the spondylolisthesis has been exactly reduced. At this point, that would be the completion of the procedure. 
         [0053]    Now the technique described above typically would be performed open, in an open procedure and also bilaterally with both pedicles and the right and the left side of the vertebral body that is in listhesis would be addressed. And then the procedure would alternate right versus left a little bit of reduction the right and then a little bit of reduction left, and then alternate the right to left so that the vertebral body is translated or reduced in a symmetrical fashion so that no undue rotation is performed during the reduction technique. And then after the reduction is complete, then again the MAC Pin  10  cut off flush to the coupler  20 . This procedure can be performed on a one level spondylolisthesis, a two level spondylolisthesis or in a situation where a spondylolisthesis is a top 1-2 or 3 segments that need to be instrumented according to the indications of the particular surgeon. 
         [0054]    This procedure can also be done percutaneous by cannulating the MAC Pin  10  so that this procedure could be performed percutaneously. That way a percutaneous posterior instrumentation of the vertebral body could be performed in adjunct with an anterior lumber interbody fusion or in adjunct with a trans lateral interbody fusion. So that this procedure and this system  10  can be utilized with almost any spinal pathology, spondylolisthesis, isthmic spondylolisthesis, traumatic spondylolisthesis also scoliosis, whether it be idiopathic or a degenerative condition, and finally spinal trauma. 
         [0055]    This system  10  also provides a different coupler  20 MO that is called a medial offset of lateral offset coupler. In this particular coupler  20 MO, the MAC Pin  10  would still be placed in the vertebral body  202 , but the coupler  20 MO would be placed not cranial and caudal but rather medial or lateral to the MAC Pin  10  and in that situation the holes  21  where the rod  100  adjoins to the coupler  20 MO would now be parallel with the rod  100  so that it could be medial or lateral to the MAC Pin  10 . And that would enable the surgeon to perform multiple spondylolisthesis reductions. For example, if you had a (L4 L5) as well as a (L5 S1) grade 1 or grade 2 spondylolisthesis, one could use the medial offset coupler  20 MO with a MAC Pin  10  at every vertebral body with a MAC Pin  10  placed at L4, L5 and S1 and then one could place a medial coupler  20 MO on each MAC Pin  10  and therefore one could perform independent distraction or compression between both motion segments and then also independent and accurate reduction of both the L4 body on L5 as well as the L5 body on S1 once again achieving complete and consistent accuracy. And that is the uniqueness this particular device  10 . 
         [0056]    The system  10  is designed to reduce spondylolisthesis whether it be grade 1, grade 2 or grade 3 according to the surgeon&#39;s desire to reduce the spine. 
         [0057]    In practicing these procedures, it is preferable that the surgeons are triangulating the MAC Pins  10  into the vertebral body  201  so that when the vertebral body  201  is pulled back or reduced that the force that is pulling the vertebral body  201  back to alignment is not only axial pullout strength, but also an actual purchase of the vertebral body through triangulating the MAC Pins  10  or converging the MAC Pins  10  from the right and left side in a triangular fashion in the vertebral body  201  so a separate force is pulling back against the mass of vertebral body  201 , not only axial pullout strength of the MAC Pin  10 . 
         [0058]    In describing how the triangulation of the MAC Pins  10  within a vertebral body  201  would work, consider for example if the surgeon is fixing a L4,5 degenerative spondylolisthesis that means that the L4 body is translated or listhesed out of proper alignment forward or anteriorly maybe 2 mm maybe 2 cm. He has to pull that L4 body back where it belongs in a direct line within the sagittal plane. That direct line must be consistently and accurately reproduced from surgery to surgery or else it could create rotation within the motion segment that will put a mechanical malalignment and possibly other problems. Every time he pulls back on spondylolisthesis an upper bone on top of a lower bone it must be in a symmetrical fashion and also along a vector directly within the sagittal plane. In order to do that, what is going to be done is to put a standard pedicle screw in the vertebral body below. The rod  100  is fixed within that pedicle screw  110  so that the pedicle screw  100 , the rod  100 , the vertebral body  202  are all fixed with respect to each other. This will serve as an anchor to pull back the L4 vertebral body within that sagittal plane. In order to establish a strong foothold in the upper vertebral body L4, the surgeon must do one thing and that is to insure a very strong purchase or grasp of that L4 vertebral body  201  and pull it back using the rod  100 , pedicle screw  110  and vertebral body  202  below once again as an anchor. Once the coupler  20  is placed on the MAC Pin  10  and the surgeon begins to pull the vertebral body above  201 , back within that sagittal plane, he must have achieved a strong foot hold and grasp of that L4 vertebral body  201 . The preferred way he would do that is from the right side and left side. He would place the MAC Pins  10  in the upper vertebral body at angles. He would come in at as an obtuse or oblique angle with respect to the sagittal plane or the vector within the sagittal plane that the bone must pull back in. In the way he want the MAC Pins  10  not only with strong axial pullout strength, but also wants the two MAC Pins  10  coming in from both the right and left side at an angle, preferably anywhere between 15 and 25 degrees in a convergent way so that the tips of the MAC Pins  10  are coming together within the midline of the upper vertebral body  201 . For example L4, once the MAC Pins  10  are hooked into the anchor at the rod  100  again to translate both right and left MAC Pins  10  with respect to the anchor or rod  100  the vertebral body  201 , the vertebral body can be translated posteriorly into alignment symmetrically within the sagittal plane. The foothold that is achieved by doing this is twofold. One, the MAC Pin  10  itself has an axial pullout strength that is going to add to the foothold. Two, by angulating the two MAC Pins  10  in a convergent manner within the vertebral body  202  increases the foothold on the medial aspect of the each of the MAC Pins  10  purchasing the mass of the vertebral body  202 , the mass of the bone also serves as a foothold for a grasp of the vertebral body  202  as the surgeon pulls the vertebral body  202  along a straight vector within the sagittal plane. It is because the angles of the MAC Pins  10  that are oblique to the sagittal plane, the force begins to pull within the vector of the sagittal plane. The obliqueness of the MAC Pin  10  has added strength for pulling the vertebral body back within that sagittal plane. Once that alignment is achieved, then the MAC Pins  10  are locked down and the actual pullout strength as well as the convergence of the two MAC Pins within the vertebral body  202  continue to hold that vertebral body within an aligned or reduced position until the fusion takes place. 
         [0059]    This system  1  allows the surgeon to pull from left and right sides if desired. The MAC Pin in the right or the left side allows not only for independent distraction or compression right versus left according to the need, but they also allow complete independent rotational control so that a surgeon if he wanted to could pull the right MAC Pin  10  back 1.5 cm, pull the left MAC Pin only 1 cm to create rotation within the vertebral motion segment so that the spondylolisthesis or scoliosis can be tuned to the situation the surgeon is seeing. The benefit of this device  10  is that if he had a rotation that could place the vertebral out of alignment, the surgeon would be able to distinctly and independently rotate, distract or reduce the vertebral right versus the left independent of each other the right or the left sides. It all depends on the technique the surgeon uses whether he reduces by the handle on the right side or the left side or both simultaneously or he can, if he chooses, utilize the MAC Pin  10  and the handle the right side versus the left side differently at different times completely independent of one another. 
         [0060]    There is nothing on the market that allows this reproducible, consistent accuracy with regard to distraction, rotation, and in particular reduction. The market has been flooded by multiple spinal instrumentation companies with what&#39;s called “reduction screws”. Reduction screws are just standard pedicle screws that have a long extended tulip. They are based on the fact that you can try and lock the lower pedicle screw in the lower vertebral body and then estimate again estimate the amount of reduction, translation or rotation that one might need and then a reduction screw is placed in the vertebral body above. At this point the theory is the rod is again fixed to the vertebral body below and again in this system the vertebral body below and the pedicle screw and the rod are fixed together and are going to be used as an anchor while the tulip and the end cap is placed on the reduction screw above. So the theory is that as the screw end cap down into this elongated reduction tulip at the relationship between the upper vertebral body and the lower vertebral body are going to remain the same and that is just simply never true and never accurate and never reproducible. 
         [0061]    As one begins to reduce the spondylolisthesis with a reduction screw, what happens is, the surgeon must rely on the anchor in the lower vertebral body  202 , the standard pedicle screw  110  and the rod  100 . And the theory is that he would like the rod  100  to be sitting the exact same distance in the tulip that he desires the spondylolisthesis to be reduced. So he is looking at an interoperative forum, so when the surgeon says he wants the reduce this spondylolisthesis let&#39;s say 5 mm, he is going to set the rod 5 mm above the bottom of the tulip on the reduction screw, then he is going to put the end cap in the reduction screw and tighten the end cap until the rod sits on the base of the tulip which will be 5 mm. The only problem with this system is that it requires that the pedicle screw and rod relationship in the vertebral body below does not change a bit. And that is where the problem with this system comes in is that it always changes. So what happens is the surgeon puts 5 mm between the rod and the tulip head and begins to tighten the end cap and what happens is that as the end cap tightens down the rod takes the vertebral body below into a different angulation and into a different position such that once you get to 5 mm of tightened down with the end cap, he may only have achieved 1-2 maybe 3 mm of reduction, and once that end cap is set within the tulip that is all he&#39;s got. So that means he wanted to reduce 5 mm, but the vertebral changed in its angle relationship, then he only had 3 mm, then he has to reset that and there is no way to change that unless he takes out the rod and starts over. That adds time to the patient&#39;s surgery and a surgeon may find himself readjusting this 2, 3 to 4 times trying to get the estimation correctly based on something he has no control over. This relationship is based on the strength of the bone, meaning that if the pedicle screw in the vertebral body below moves, if it toggles within the vertebral body then that is going to take away 2-3 mm or if the polyaxial head of the screw anchor in the lumber vertebral body below starts to move at all will take away 2-4 mm of reduction. And finally, if the relationship within the sagittal plane of the upper vertebral body and the lower vertebral body begin to change with the respect to one another as the end cap is tightened down assuming the rod, the pedicle screw and the lower vertebral body are indeed fixed, then what has happened is the two vertebral bodies move inappropriately with relationship to each other and then again a loss of 3, 4, 5 mm of reduction occurs and so what it&#39;s going to result in is making the surgeon accept mediocrity. While reducing a grade 2 spondylolisthesis, to 0 in perfect alignment is usually found with that type of prior art instrumentation is a grade is not completely reduced, not completely restored within that mechanical alignment in the sagittal plane. In the present invention system  1 , the surgeon does not have to worry about those things. He won&#39;t have to even consider any of those things that cause problems with the reduction screw system, because the MAC Pin  10  allows adjustable, and reproducible amount of reduction or translation regardless of the relationship of the lower vertebral body  202 , it has no bearing on the procedure other than being an anchor point. You can take it to 1-2 cm, if you want to you can take anterior again, so you have complete control forward and backwards moving this vertebral body anywhere in space you want to and that is within the interoperative amount of time which is so important that with the system  1  which takes less than 5 minutes to reproduce consistently, the device  10  allows free independent reduction and rotation of vertebral body  201  with an additional time of less than 5 minutes. And no one can argue that the reduction pedicle screws allow for that amount of control with that few minutes of interoperative time addition. 
         [0062]    With regard to application of the system  1  in scoliosis, the MAC Pin  10  would be used and probably in every level of the scoliosis. As shown in  FIGS. 10A and 10B , in a scoliotic spine  200  where a curve had to be reduced in the sagittal plane but also rotationally reduced, the MAC Pin  10  would be placed bilaterally, most likely, sometimes unilaterally in multiple levels throughout the entire affected instrumented spine. Every level that is going to be addressed with instrumentation in scoliosis may have one or two MAC Pins  10  in them. With regard to the coupler  20 , in scoliosis, most likely the coupler  20  could be a medial offset coupler  20 MO or a lateral offset coupler  20 LO as opposed to the cranial coupler  20  that would be used in spondylolisthesis. In the coupler  20 MO or  20 LO, the rod connection opening is positioned on a side of the coupler body  24  as shown in  FIGS. 4F-4I . In this alternative embodiment, the MAC Pin  10  is made as at least a two part assembly, the pedicle screw  12  and the smooth transition  16  and second threaded portion  14  are separate pieces. Otherwise the alternative embodiment is similar in construction as the system  1  previously discussed. As designed one can use a coupler  20  as previously described in  FIGS. 4-4B  having monoaxial adjustment or a polyaxial construct as shown in  FIGS. 4C-4E , or use a fixed coupler  20  design as illustrated for the couplers  20 LO/ 20 MO which by design are the same in terms of the location of the rod opening  22 . This allows the use of multiple MAC Pins  10  within the spine  200  and then the rod  100  would be placed either medially or laterally through the MAC Pin  10  and then coupled to the MAC Pin  10  again from the medial side or the lateral side. The rod  100  would most likely be utilized bilaterally in both the right and the left side to add a foothold or strength to the purchase of the various vertebral bodies of the spine  200  for not only reduction in not only the sagittal and coronal plane again also rotational such that again the MAC Pin  10  on the right side of the vertebral body  201  versus the MAC Pin  10  on the left side of the vertebral body  201 . Either way has complete independence from each other so that a surgeon may be able to utilize the MAC Pin  10  for rotation on the right side by leaving the left side in place. So the medial coupler  20 MO purpose or lateral coupler  20 LO simply would allow the MAC Pin  10  to be utilized in the vertebral body at multiple different levels. The MAC Pin  10  with regard to scoliosis procedures likely would be exactly the same, however, the coupler  20  going from what is called the cranial coupler to a medial or a lateral offset coupler, required the coupler design to be slightly different in the fact that the coupler  20  is slipped over the MAC Pin  10  and if for example the medial offset is placed on the MAC Pin  10 , the rod  100  would be placed medial to the MAC Pin  10  so therefore the slot or the hole  21  within the coupler  20  would need to run parallel with the axis of the spine  200 , such that the only difference would be that the coupler  20 MO allows the rod to be medial to the MAC Pin  10  as opposed to being caudal to the MAC Pin  10 . So the wrenches  70  that would be used would be the same, the two nuts  60  would be very similar, the only difference would be the relationship to the right of the MAC Pin and this is all based on the fact that the surgeon would need to place multiple MAC Pins  10  throughout the spine  200 . 
         [0063]    With regard to the physical structure of the MAC Pin  10 , this will be a one piece titanium pin with two sets of threads, there will be a pedicle screw portion  12  that will measure anywhere from 35 to 55 mm and will replicate at this point a pedicle screw thread. That typically is a double lead pedicle screw self-tapping thread with the single pole. Alternatively, in future generations the thread can be with the double threaded dual core system for the pedicle portion of the MAC Pin  10 . Beyond the inner tip  11 A of the pedicle screw portion  12  of the MAC Pin  10  there will be a smooth shaft portion  16  that will be from 1 to 2 cm or 1 to 3 cm in length and will be the same dimensions or radius as the inner core or shaft of the MAC Pin  10  most likely of the pedicle screw portion and that will be the space that is allowed for coupling of the coupler  20  to come down over the MAC Pin  10 . Furthermore beyond the smooth shaft portion  16  of the MAC Pin  10  there will be an outer portion  14  with a second set of threads. That second set of threads will be the threads that are actually used for the reduction or rotation of the vertebral body  201  by virtue of the fact that cannulated smooth shaft hitting a smooth surface of the coupler  20  over the MAC Pin  10  and this smooth cannulated tower has an inner set of threads that will operate and engage with the outer second set of threads on the outer portion  14  of the MAC Pin  10 . When the cannulated handle goes over the tip  11 B of the MAC Pin  10  and one rotates the outer cannulated tower  40  with respect to the MAC Pin  10  and because the coupler  20  is fixed to the rod  100  and vertebral body below, as you rotate the shaft  40  over the MAC Pin  10  that begins to pull the MAC Pin  10  in posteriorly within the sagittal plane and obviously the pedicle screw itself threaded within in the vertebral body  202  is going to pull the vertebral body back. So the final and last portion of the post or end of the MAC Pin  10  is simply again some type of squared off structure that will allow potentially a grasp of the MAC Pin so it can be rotated, if desired. The tip of the MAC Pin  10  may be smooth or squared off, it doesn&#39;t matter to the function of the MAC Pin because all of the function of the MAC Pin  10  takes place in the second set of threads within the cannulated tower  40 . The MAC Pin  10  is a screw that can be used with an open procedure, but the same pin can be cannulated for the purpose of percutaneous reductions and percutaneous use. The coupler  20  is loose on the non-threaded smooth shaft portion  16 . The coupler  20  that is on the MAC Pin  10  is loose on the smooth shaft portion of the MAC Pin and that relationship is not fixed. So although the tower between the outer diameter of the shaft pin and the inner diameter of the coupler is quite small it does allow the MAC Pin  10  to shift or cam within the coupler  20  so that as you are tightening down the cannulated tower  40 , the MAC Pin  10  is actually shifting or moving with respect to the coupler  20  so that the vertebral body portion of the MAC Pin  10  is remaining fixed. So the MAC Pin  10  within the vertebral body does not move, it only pulls the vertebral body  201  back through the cam action between the cannulated tower  40  and the coupler  20  and the MAC Pin  10 . That is why the MAC Pin  10  is made smooth on that one portion of the pin  10 . As you are pulling the vertebral body  201  back you are rotating the cannulated tower  40  moving outwardly the MAC Pin so the inner threads within the shaft  40  are operating in conjunction with the outer threads of the MAC Pin  10  so that the both sets of threads are slowly driving the vertebral body back within the sagittal plane. The MAC Pin  10  moves fore or aft relation to the rotational direction of the shaft  40 . Importantly, the MAC Pin  10  is not rotating as the cannulated tower  40  rotates and pushes against the coupler  20 . The rod  100  has already been placed in the coupler  20 , the rod  100  and the pedicle screw  110  below are the anchor. The MAC Pin  10  could spin within the coupler  20  at this point, but keep in mind the coupler  20  is fixed to the rod  100  which is fixed to the pedicle screw  110  below. The only motion that is remaining is the camming effect with respect to the MAC Pin  10  inside of the coupler  20 . Once the cannulated tower  40  has reduced the spondylolisthesis to the desired amount the cannulated tower  40  stays in place, one takes the handle or cogwheel  50  off the top and a cannulated wrench  70  is placed over both the cannulated tower  40  and the MAC Pin  10  and goes all the way to the coupler  20  where there is a nut  60  to tighten. As the nut  60  tightens, the relationship between the coupler  20  and MAC Pin  10  becomes fixed. There are two nuts on the coupler  20 , one nut  102  is in order to fix the coupler  20  to the rod  100 , the other nut  60  is placed on the threaded end of the coupler  20  over the MAC Pin  10 . So the nut compresses the coupler at the same hole that accommodates the MAC Pin  10 , so when the coupler is all the way down on the bone one tighten the nut and it fixes the relationship between the MAC Pin  10  and the coupler  20 . When one sends the cannulated tower  40  down the MAC Pin  10  the threads between those two entities are locked together that is what gave the reduction and so you leave that cannulated tower  40  on until one puts the wrench  70  over and tightens the nut  60 . That fixes everything, it fixes the relationship between the coupler  20  and the MAC Pin  10 , therefore locks in the reduction achieved with the vertebral body in place. The nut  60  is sitting there on the coupler  20  and doesn&#39;t get tightened until one tightens it with the cannulated wrench  70 . The nut  60  as designed will slide over the cannulated tower  40  and onto the coupler  20  so the nut  60  is going to slide over the shaft  40  and tighten on that slotted thread end area on the coupler  20  and when that area on the coupler  20  gets tightened down it will tighten down on the smooth shaft portion  16  of the MAC Pin  10 . 
         [0064]    Interbody fusion is not necessary, but if desired after shearing off MAC Pin post. The only implant you would have would be an interbody implant. 
         [0065]    After the instrumentation has been placed after the MAC Pin has been sheared off flush with the coupler, the reduction and the distraction or compression of the spondylolisthesis has been achieved and has been fixed with regard to the instrumentation. If a surgeon chooses at this point to decompress the neural elements or wishes to provide an interbody discectomy fusion or placement of an interbody posterior implant, now is the time that would be performed. At this point again after the instrumentation is complete with respect to the MAC Pin and the rod, a laminectomy or a laminotomy can be performed decompressing the neural elements. At this point a standard posterior lumber interbody fusion or a transforaminal lumbar interbody fusion can be performed. In which case the nerve root that has distracted from the midline and anulotomy is performed and the discwork including a total discectomy endplate preparation, insertion of bone graft material of choice and lastly insertion of a posterior interbody bone graft or cage dependent on surgeon&#39;s choice can be placed within the interbody space of the affected motion segment. 
         [0066]    In that situation, the inventor has found that after distracting with the rod posteriorly that one can now place an interbody graft within the anterior column of the disc space and create a parallel distraction of the disc height and therefore restoring lordosis. At this point it is also available with this system once the interbody implant has been placed in the anterior column of the intervertebral disc space, it is now possible to leave the coupler and the MAC Pin fixed but if a surgeon wanted to compress on an interbody implant he would then simply go to the lower pedicle screw in the lower vertebral body, loosen the end cap and therefore enable them to compress on the rod thus, interbody implant and then retighten the end caps maintaining the listhesis but allowing once again independent distraction or compression. 
         [0067]    With regard to placing the interbody implant, once the instrumentation is performed and the spondylolisthesis is reduced and locked in placed and fixed at that time a laminectomy or a laminotomy can be performed according to the surgeon&#39;s indication. At this point also would be a laminotomy and perhaps a posterior lumbar interbody fusion or a transforaminal interbody fusion. Also at that time the vertebral body may be retracted toward the midline and an anulotomy is made, and then finally a discectomy is performed in preparation and insertion of bone graft material according to the surgeon&#39;s choice. Once the bone graft has been placed in the interbody space, the surgeon then inserts the posterior interbody graft or cage according to his desire. 
         [0068]    After the placement of the interbody structure the surgery would be complete. There is an option if the surgeon wants to create more lordosis, he has two different ways to do that. One would be to insert a large interbody graft anteriorly in the anterior column as one is opening up the anterior disc space creating parallel disc height distraction or even a lordotic alignment. The second method by which the surgeon could create lordosis with this system  1  is at this point once the interbody implant is placed in the anterior column. He can loosen the end caps in the lower vertebral body standard pedicle screw and then perform compression of the rod within the standard pedicle screws at which point he will therefore be compressing not only the interbody graft or cage but also creating a lordotic alignment within the motion segment that has been instrumented. Once that compression takes place, then the surgeon would simply tighten up the end caps in the pedicle screws below and then the entire concept would be rigid and fixed. All the while the spondylolisthesis by virtue of the MAC Pin  10  and the coupler  20  have been made fixed and therefore the spondylolisthesis does not change, this is a unique feature to the system  1 . If a reduction pedicle screw on the lower pedicle screw is locked in the monoaxial position, and forms the anchor by which the reduction screw is going to be utilized using the prior art technique, the surgeon can then not go back and loosen this tulip head or else the reduction would be lost if the reduction screw had changed. This unique system  1  allows that feature which is again another benefit to accuracy and reproducible consistency of the system. The system with regard to rotational control as well as reduction control within that part of the spine. At this point the surgery would be complete and the surgeon would then begin his standard closure. 
         [0069]    One of the other features that is unique within the coupler  20  is that the MAC Pin  10  relationship within the coupler  20  not only has a cam relationship that can shift within the coupler  20  up and down, but it also will be able to change angulation with respect to the coupler  20 . That is the MAC Pin  10  will be able to change the angulation with regard to the coupler within the sagittal plane. There is a shaft holding coupling mechanism  90  within the coupler  20 , a separate shaft holding coupling mechanism  90 , within the titanium coupler  20  that moves with relationship to the coupler  20  itself, so as the MAC Pin  10  comes down through the coupler  20  it is also coming through this separate device  90  so that this coupling  90  allows movement within the sagittal plane with respect to the coupler and the importance of that is to allow MAC Pin  10  to enter into the pedicle at the vertebral body at different angles cranial or caudal within the sagittal plane. So that when the coupler  20  and the rod  100  are introduced simultaneously over the MAC Pin  10 , if there is an odd or unexpected angle in order for the caudal aspect of the rod  100  to fall into the top loading tulip of the pedicle screw  110 , this motion within the coupler  20  will accommodate that need. Such that when the coupler  20  is placed over the MAC Pin  10 , and the rod  100  needs to fall down into the space of the tulip head of the pedicle screw  110  below that shaft holding coupling mechanism  90  within the coupler  20  and that motion would then apply to the frame to allow that accommodation to occur. A side to side motion with respect to the device  90  inside the coupler  20  also can be provided to match the couple relationship. That purpose will be to allow surgeons a larger margin of error with regard to the angle at which he places his MAC Pin  10  into the vertebral body. So the system  1  allows for a margin of error respecting the fact that not all surgeons are going to optimally position the device  10  every time. The device  10  automatically can compensate for this fact. The placement of pedicle screws has long been known to be a skill that is developed and learned by each individual spine surgeon. So it was desirable to want to remove as much requirement for the perfect placement of this MAC Pin within the vertebral body as possible, therefore allowing the largest margin of error for surgeons to place the MAC Pin and then connect it through a rod, pedicle screw below. This device within the coupler currently has the ability to move within the sagittal plane both cranial and caudally allows for that and allows the coupler  20  to be attached to the rod  100  in the pedicle screws. Preferably, the coupler  20  is designed with  360  degree motion so as to allow the surgeon margin of error not only in the sagittal plane but also within the coronal plane such that regardless of the surgeons ability to place the MAC Pin  10  appropriately within the vertebral body, the attachment into the rod  100  and the pedicle screw  110  below would be made even easier for that surgeon. 
         [0070]    In another embodiment, the device or system  1  provides a percutaneous MAC Pin  10 . The MAC Pin  10  design would be the same; however, it is cannulated inside the entire length pin such that this could be done with a minimally invasive procedure as opposed to an open procedure. That would decrease the patient&#39;s postoperative pain, decrease the blood loss, decrease the hospital stay length, as well as decrease the patient&#39;s long term postoperative pain. Another benefit of doing this procedure percutaneously is that one could then couple this procedure with an anterior lumbar interbody fusion or perhaps a translateral interbody fusion and use a separate approach while placing these pins and reduce the spondylolisthesis percutaneously or in a minimally invasive technique. 
         [0071]    With regard to the coupler  20 , the coupler  20  probably would not change although modification improvements of the coupler  20  are certainly possible. The most important part of the procedures would remain the same the MAC Pin and the fact that under fluoroscopic assistance interoperatively a stab wound in the skin would be made as opposed to a complete opening of the skin and muscle tissue. So a small k wire (kirschner wire) could be inserted into the pedicle and finally into the vertebral body maintaining the above described technique and that would be followed by the placement of MAC Pins that would be cannulated and then attached to the coupler and the pedicle screw below. Similarly described in the open procedure. A jamsheedy needle would be used to place the guide wire into the vertebral body again percutaneously or minimally invasive and this is certainly a standard well known part of the procedure. However, once the guide wire  80  had been placed and confirmed to be in the appropriate placement, per the interoperative fluoroscope and that would be followed by measuring of the pedicle screw portion of the MAC Pin and then placement of the MAC Pin  10  with a cannulated opening  13  over the guide wire  80  and into the vertebral body to appropriate position based on the interoperative fluoroscope. 
         [0072]    The next step would be placement of percutaneous pedicle screws, shown in  FIGS. 12A-12C , in the previously described placement of percutaneous pedicle screws already established by the assignee of this system as described in co-pending US patent publication 2013/0172937 A1 entitled “Extended Tab bone Screw System” filed Dec. 19, 2012; which is incorporated by reference herein in its entirety; and finally the coupler  20  would be applied over the MAC Pins  10  as described in the open technique and placed within the tulip head below through a minimally invasive being separately described. In another aspect, the two leg extensions are connected via a connector  249  positioned at a point spaced therefrom the first end of the leg extension and spanning the first insertion tool pathway  270 . In one aspect, the connector is positioned substantially perpendicular to the longitudinal axis AL. Positioning the connector  249  a predetermined distance from the first end provides a fulcrum point from which a rod insertion tool can rotate. As seen in  FIGS. 19 ,  20  and  21 , the stabilizer rod is positioned between the leg extensions with the insertion tool. As the stabilizer rod is positioned lower and toward the second end of the leg extensions, the insertion tool is partially positioned between the leg extensions. At this point, the handle of the insertion tool can be lifted, using the connector as a fulcrum to push the stabilizer rod into position within the rod receiving channel. At that point once again, the end caps on the pedicle screws below would be tightened and fixed once again to serve as an anchor for the MAC Pin after which the surgeon would go back to the MAC Pin  10  and begin the translation and distraction procedure as described above such that after reduction was achieved through the action of the MAC Pin, the cannulated wrench would be slipped over and the nut would once again be tightened and a separate shearing device would be developed to shear the MAC Pin flush with the coupler. And once again the surgeon has achieved a fixed reduced spondylolisthesis that he can now go and perform either anterior lumbar interbody fusion, lateral and foraminal interbody fusion or a posterior lumbar interbody fusion and perhaps even “OLIF” at this point consistent with amendia&#39;s portfolio. 
         [0073]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described, which will be within the full intended scope of the invention as defined by the following appended claims.

Technology Classification (CPC): 0