Abstract:
The gripping device ( 1 ) enables the introduction and attachment of a set screw ( 101 ) within a U-shaped link connector ( 102 ) of a polyaxial or monoaxial pedicle screw ( 103 ) to immobilize a connecting rod ( 104 ) of a osteosynthesis device ( 100 ), and includes a locking element ( 2 ) which is supported against the link connector ( 102 ) making it possible to ensure concentricity between the principal axes of the gripping device ( 1 ) and those of the link connector ( 102 ) and to ensure that the connecting rod ( 104 ) is kept on the inside of the link connector ( 102 ); and an element for releasing ( 3 ) the gripping device ( 1 ) after establishing and screwing the set screws ( 101 ) inside the link connector ( 102 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to a gripping device enabling the introduction and attachment of a set screw within a U-shaped link connector of a polyaxial or monoaxial pedicle screw to prevent rotation and translation of a connecting rod of an osteosynthesis device which is known per se. 
     BACKGROUND OF THE INVENTION 
     Gripping devices of this type are known which allow set screws to be introduced inside a link connector to immobilize a connecting rod. 
     For example, we note that the gripping devices most known per se and described in prior patents US2004/0049191 and WO2008039441 teaches the attachment of a link connector by means of a hinge system or an elastic deformation device. These solutions do not facilitate a good grip on the link connector, spontaneously and frequently undipping, nor do they make an easy release possible, an inability to extract said link connector due to interference from the flesh, for example. 
     Earlier gripping devices do not allow one to adjust and ensure alignment between the main axes of the device and those of the link connector built into the pedide screw. 
     This condition requiring adjustment of the alignment, is indispensable to make the gripping device practical to use and to limit the patients risk of a bad attachment of the connecting rod into the link connector of the osteosynthesis device known per se. 
     The gripping device in accordance with this invention, enables the introduction and attachment of a set screw within a U-shaped link connector of a polyaxial or monoaxial pedide screw to immobilize a connecting rod of an osteosynthesis device which is known per se. 
     SUMMARY OF THE INVENTION 
     The gripping device in accordance with this invention comprises:
         A means for locking which is supported against the link connector making it possible to ensure alignment between the principal axes of said gripping device and those of the link connector and to ensure that the connecting rod is kept on the inside of said link connector;   And a means for releasing the gripping device after establishing and screwing the set screws inside the link connector.       

     The gripping device according to this invention comprises a means for locking which consists of:
         a guide body ensuing the placement of said gripping device around the link connector of the pedide screw;   a sleeve with flexible tabs having a shortened profile for assembling around the guide body;   and a means of translation constituting a guide handle which operates, first, via a double threaded link to the guide body and, secondly, by means of a pivot connection with a tube that pushes a guided rod to the inside and with respect to said guide body of said gripping device, in order to drive the connecting rod to the inside of the link connector and to have it rest upon the upper peripheral edge of said connector, said means of translation makes it possible to generate pressure force between said link connector and said tube which pushes the rod causing a displacement of the guide body so that it abuts against the flexible tabs of said sleeve having a suitable angle to block the inside space arranged inside the link connector.       

     The gripping device according to this invention includes a means for release (unlocking) which is constituted by a lever that provides guided rotation relative to the guide body, making it possible, after the release of the translational means, to exert translational force on the sleeve to the flexible tabs so as to move the latter with respect to said guide body causing separation of the flexible tabs and the release of said gripping device from the link connector. 
     The gripping device according to this invention comprises a guide body which is formed from a longitudinal tube comprising a first end provided with two lateral and opposite recesses defining two retaining branches in which the guide slots are arranged and a second end comprising an internal thread which works with the external one on a guiding handle. 
     The gripping device in accordance with this invention, comprises a guide body comprising on its external surface and between its two ends, a retaining means to introduce and attach the sleeve having flexible tabs so that the ends of said flexible tabs open into the guide slots of each retaining branch. 
     The gripping device according to this invention comprises a guide body comprising a linking means on the second end which works with those of the lever with the means of release allowing the latter to turn around said body and to then exert a translational force on the sleeve with flexible tabs so as to move the latter with respect to said guide body. 
     The gripping device according to this invention comprises a tube to push the rod of the translation means having a first end which works with the guide handle and a second end comprising two opposing projections, each having a concave shaped seat intended to work with the connecting rod of the osteosynthesis device in order to allow centering of the latter within the link connector. 
     The gripping device according to this invention comprises a push tube for a rod, the projections of which respectively comprising an external profile making it possible for angular indexing of said tube to push the rod inside of the guide body so that the concave shaped seat is always positioned in the lateral recesses of said guide body to allow passage of the connecting rod of the osteosynthesis device. 
     The gripping device according to this invention comprises a push tube for the rod comprising at the projections, a stop making it possible, when tightening the gripping device to ensure alignment of the principal axes of the link connector with those of said gripping device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description that follows with regard to the attached drawings, given as non-limiting examples, will make it possible to better understand the invention, the characteristics which it presents and the advantages which are likely to be obtained: 
         FIGS. 1 and 2  are exploded views in perspective that illustrate the different elements constituting the gripping device according to this invention. 
         FIGS. 3 and 4  are side views showing the gripping device according to this invention in its assembled position. 
         FIGS. 5A to 5D  are side and cross sectional views showing the guide body of the gripping device according to this invention. 
         FIGS. 6A to 6C  are side views and in perspective illustrating the lever with the release means of the gripping device according to this invention. 
         FIGS. 7A to 7B  are side views and in perspective showing the sleeve with the flexible tabs of the gripping device according to this invention. 
         FIGS. 8A and 8B  are side views showing the guide handle with the translating means of the gripping device according to this invention. 
         FIGS. 9A and 9B  are side views illustrating the push tube for the rod of the translation means of the gripping device according to this invention. 
         FIGS. 10A and 10B  are views in perspective illustrating the introduction of a counter-torque device that works with the gripping device to ensure the tightening of the set screw of the osteosynthesis device. 
         FIG. 11  is a cross-sectional view showing the set up of a device to insert the set screw inside the gripping device according to this invention. 
         FIGS. 12A to 12D  are cross-sectional views showing the various stages of the release channel of the gripping device on a link connector of a polyaxial pedide screw of an osteosynthesis device known per se. 
         FIGS. 13A to 13D  are cross-sectional views showing the various stages of the release channel of the gripping device of the link connector of a polyaxial pedide screw of an osteosynthesis device known per se. 
         FIG. 14  is a detailed cross-sectional view showing the load and damping chain of the gripping device on the polyaxial pedide screw link connector of the osteosynthesis device known per se. 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIGS. 1 to 4 and 11  show a gripping device  1  comprising a means for locking  2  and a means for release  3  making it possible to introduce and tighten a set screw  101  on the inside of a U-shaped link connector  102  of a polyaxial or monoaxial pedicle screw  103  to immobilize a link rod  104  to prevent its translation and rotation on an osteosynthesis device known per se. 
     The means for locking  2  of the gripping device  1  is designed to be supported on the link connector  102  in order to ensure alignment of the principal axes of said gripping device  1  with those of said link connector  102  and also to maintain its immobilization with respect to the connecting rod  104  within and near the bottom of the U-link connector. 
     The means for release  3  makes it possible, after tightening the set screw  101  on the inside of the link connector  102  and locking the connecting rod  104  against rotating or translating in the bottom of the U, to release the locking means  2  and to release the gripping device  1  from the link connector  102  of the pedide screw  103  known per se. 
     The means for locking  2  is constituted by a guide body  4  to ensure the establishment of the gripping device  1  around the link connector  102  of the pedide screw  103 , of a sleeve  5  with flexible tabs  5   a ,  5   b  and a means for translation  6 . 
       FIGS. 5A to 5D , the guide body  4  of the means for locking  2  is shown, in a lengthwise profile of the tube  4   a  comprising a first end provided with two lateral and opposing recesses  4   b ,  4   c  opening to the outside to provide the passage of the connecting rod  104  and delimiting two retaining branches  4   d ,  4   e  in which the guide slots are respectively arranged  4   f ,  4   g.    
     The external surface of each branch  4   d ,  4   e  and in the projection of the guide slots  4   f ,  4   g  comprises a flat edge  4   h  opening into a groove  4   i  making it possible to guide the flexible tabs  5   a ,  5   b  corresponding to the sleeve  5 , when it is mounted around said guide body  4 . 
     The inner surface of each branch  4   d ,  4   e  comprises a spur  4   j  having a dual-slope profile enabling locking and releasing the flexible tabs  5   a ,  5   b  corresponding to the sleeve  5  when the latter comes into contact with the link connector  102 . 
     The longitudinal tube  4   a  comprises, opposite the first end, a second end comprising in its interior a threading  4   k  that works with that  7   a  of a guide handle  7  for the means of translation  6 . 
     The outer surface and the second end of the longitudinal tube  4   a  comprises a cavity form  4   l  which couples with a handling tool  200  ensuring a counter torque device during the final tightening of the set screw  101  by means of an input device  300  ( 10 A,  10 B and  11 ). 
     Between the two ends of the longitudinal tube  4   a , an external diameter is comprised which is smaller than that of said ends for receiving the sleeve  5  with the flexible tabs whose outer diameter is trimmed above the axis to ensure securing the assembly and the translation guide of said sleeve around said tube. 
     To do this, near the first end of the longitudinal tube  4   a , there is a circular abutment  4   m  having a beveled profile which works with a stop  5   c  having a complementary profile arranged between the flexible tabs  5   a ,  5   b  of the sleeve  5  ( FIGS. 5C, 7A and 7B ). 
     Also, on the reduced portion thereof and opposite to the circular abutment  4   m , the longitudinal tube  4   a  is provided with oblong openings  4   n  which are diametrically opposed to allow reception of the internal ribs  5   d  positioned opposite the flexible tabs  5   a ,  5   b  and exits the trimmed profile of the sleeve  5  ( FIGS. 5B, 7A ). 
     Close to the cavity form  4   l , the longitudinal tube  4   a  comprises a semicircular rib  4   p  carrying at each end of the pins  4   g  working respectively with the holes  9   a  arranged at one of the ends of a lever  9  of the means to release  3  so as to a pivotal connection between said lever and the guide body  4  ( FIGS. 5B, 6B and 6C ). 
     In  FIGS. 7A, 7B  the sleeve  5  having flexible tabs  5   d  is shown, with guide axes  5   e  external ribs on the outer surface which respectively work with an indined and through-fitted groove  9   b  arranged in the inner part of the release lever  9  and opposite the holes  9   a  to convert the rotational movement of said lever  9  around the guide body  4  into a translational movement of said sleeve  5  along said guide body. 
     The release lever  9  comprises a lamella  9   c  machined from the body and plastically deformed towards the interior of said lever to form a return spring between the guide body  4  and the release lever  9  ( FIGS. 6A and 6B ). 
     The sleeve  5  comprises in the projection of its trimmed profile and opposite the guide axes  5   e , flexible tabs  5   a ,  5   b  which are each constituted of a flexible part  5   f  which flex and an inner profile comprising an inclined wedge  5   g  and a spur  5   h  separated by a receiving space  5   i  ( FIGS. 7A, 7B and 11 ). 
     Each indined wedge  5   g  make it possible to separate the flexible tabs  5   a ,  5   b  when the gripping device  1  is released from the link connector  102  of the pedide screw  103  using the lever  9  with the release means  3 . 
     Each spur  5   h  has an oriented chamfer  5   j  and a flat edge  5   k  respectively ensure the insertion and maintenance during translation of the flexible tabs  5   a  and  5   b  to inside of the blind holes  105  implemented on both sides of the link connector  102  of the pedicle screw  103  known per se. 
     In  FIGS. 8A, 8B and 10B  the guide handle  7  of the translation means  6  is shown which consists of a cylindrical tube  7   b  perforated throughout by internal boring  7   c  for the passage and guidance of an input device  300  carrying the set screw  101  of the osteosynthesis device  100  known per se. 
     The cylindrical tube  7   b  comprises a gripping knob  7   d  built into one of its ends ensuring the surgeon has a perfect grip on the translation means  6 . 
     The outer surface of the cylindrical tube  7   b  is machined to have a right handed double thread  7   a  enabling the conversion of the rotational movement into a translational movement when the surgeon uses the guide handle  7 . 
     The cylindrical tube  7   b  comprises an projection of the double thread  7   a ; a quick coupling device constituted by flexible tabs  7   e  regularly distributed around the periphery of said tube and a rotary knob housed within the cylindrical tube  7   b  and for performing the pivot connection with the push tube for the rod  8 . 
     In  FIGS. 9A and 9B  the push tube for the rod  8  of the translation means  6  is shown that comprises a first end  8   a  of a cylindrical form and complementary to that of the coupling device with flexible tabs  7   e  and a rotary knob so as to work with the cylindrical tube  7   b  of the guide handle  7 . 
     The push tube for the rod  8  comprises a second end  8   g  constituted of two opposing projections  8   b ,  8   c  each presenting a concave seat  8   d  designed to work with the connecting rod  104  of the osteosynthesis device  100  known per se in order to allow centering of the latter within the link connector  102 . 
     The projections  8   b ,  8   c  of the push tube for the rod  8  respectively comprise an outer profile  8   e  that work with a complementary form arranged on the inside of the guide body to make angular indexing possible for said tube to push the rod inside the guide body  4 . 
     This angular indexing of said push rod  8  relative to the guide body  4  makes it possible for the concave seat  8   d  to always be positioned in the lateral recesses  4   b ,  4   c  of said guide body  4  to make the passage possible of the connecting rod  104  of the osteosynthesis device  100  known per se. 
     At projections  8   b ,  8   c  of the push tube for the rod  8 , there is a stop  8   f  which stops the action when tightening with the gripping device  1  the pedicle screw  103  rests on top of the link connector  102  so as to ensure alignment of the principal axes of said link connector  102  with those of said gripping device ( FIGS. 9A and 11 ). 
     This alignment between the principal axes of the link connector  102  and the gripping device  1  makes it possible to correctly position the set screw  101  before its introduction and before it will work with the internal threading  106  of the link connector  102  ( FIG. 11 ). 
     FUNCTIONING OF THE INVENTION 
     In  FIGS. 12A to 12D , the release channel of the gripping device  1  is shown on the link connector  102  of the pedide screw  103  known per se. 
     The polyaxial or monoaxial pedide screw  103  provided with a link connector  102  must be first anchored in the pedide of the Pv vertebra of a spinal segment of a spinal column to be fitted with the osteosynthesis device  100  known per se. The connecting rod  104  must also be presented above the link connector  102 . 
     The surgeon presents and approaches the gripping device  1  so that the retaining branches  4   d ,  4   e  of the guide body  4  are resting against the upper edge of the U-shaped branches of the link connector  102 . 
     In this position, one notes that the recesses  4   b ,  4   c  of the guide body  4  are within the projection of the openings of the U-shaped connector  102  to allow for the passage of the connecting rod  104 . 
     The surgeon then bears down on the gripping device  1  guided along the U-shaped link connector  102 . In this way, the flexible tabs  5   a ,  5   b  of the sleeve  5  deform around the link connector  102  by clipping into the blind holes  105  of the link connector. The gripping device  1  is then fixed onto the link connector  102  of the pedide screw  103 . 
     Then the surgeon actuates the knob  7   d  of the guide handle  7  in order to move the push tube for the rod  8  with respect to the guide body  4  and thus with regard to the link connector  102  of the pedicle screw  103 . The push tube for the rod  8  enters into contact with the connecting rod  104  due to its seats  8   d  and pushes the latter in a centered manner into the bottom of the U-shaped profile of the link connector  102  ( FIGS. 12C and 12D ). 
     When the push tube for the rod  8  comes into contact above the link connector  102 , it is stopped. The force of the pressure between the push tube for the rod  8  and the top of the link connector  102  causes an adjustment to occur between the guide body  4  and said link connector  102  ( FIG. 14 ). 
     This adjustment makes it impossible for the flexible tabs  5   a ,  5   b  of the sleeve  5  to move apart because they are blocked by the ends of the retaining branches  4   d ,  4   e  of the guide body  4  ( FIG. 14 ). 
     As soon as the push tube for the rod  8  is in abutment against the top of the link connector  102 , the gripping device  1  is completely fixed and secured to said link connector  102  making the main axes of said gripping device  1  aligned with those of said link connector  102 . The alignment of the main axes makes it possible to correctly position the set screw  101  by using the input device  300  in order for the latter to work with the internal threading  106  of the link connector  102  ( FIGS. 12A to 12D and 14 ). 
       FIGS. 13A to 13D  show the release canal of the gripping device  1  of the link connector  102  of a pedicle screw  103  known per se. 
     The release of the gripping device  1  from the link connector  102  requires release of the pressure generated by said gripping device on said actuator connector in a direction that is the opposite of the action used with the knob  7   d  of the guide handle  7 . 
     By moving the push tube for the rod  8  in a direction that is the opposite of the link connector  102 , free game is set up between the guide body  4  and the flexible tabs  5   a ,  5   b  of the sleeve  5 . 
     By actuating the release lever  9 , the sleeve  5  with flexible tabs is moved in a direction opposite to the link connector  102  causing the flexible tabs  5   a ,  5   b  of the sleeve  5 , to open as they are left free due to the play produced between them and the guide body  4 . 
     The opening of the flexible tabs  5   a ,  5   b  of the sleeve  5  occurs due to the two inclined wedges  5   g  arranged on the internal surface of said flexible tabs that are up and along the guide body  4 , respectively resting on the flat edges  4   h  of the retaining brandies  4   d ,  4   e  forcing them to move apart from the link connector  102 . 
     Then the opening between the flexible tabs  5   a ,  5   b  is sufficient, the gripping device  1  is disconnected from the link connector  102  allowing it to be withdrawn. 
     It should be understood that the above description was given only as an example and by no means limits the field of the invention, nor will it be outside the field of the invention, if implementation details described are replaced with any other equivalent.