Instrumentation for stabilizing certain vertebrae of the spine

Information

  • Patent Grant
  • 6786907
  • Patent Number
    6,786,907
  • Date Filed
    Tuesday, April 23, 2002
    22 years ago
  • Date Issued
    Tuesday, September 7, 2004
    20 years ago
  • Inventors
  • Original Assignees
  • Examiners
    • Shaver; Kevin
    • Ramana; Anuradha
    Agents
    • Browdy and Neimark, P.L.L.C.
Abstract
The instrumentation includes a spinal stabilizing longitudinal element (1) that is adapted to be placed in a generally parallel relationship with the portion of the spine (A) to be treated, a connector (6) having an opening (7) therethrough, a mechanism (10) is adapted to affix said bone-anchoring element (2) in the opening (7); the connector (6) has a hook portion (11) adapted to cooperate with a support (32) of the bone-anchoring element (2) for clamping the longitudinal element (1); the hook portion (11) has at its bottom side a recess (12) for receiving the longitudinal element (1); the longitudinal element (1) is clamped against said support (32), so that the force of the support (32) on the longitudinal element (1) is approximately parallel to the axis (D) of the bone-anchoring element (2).
Description




BACKGROUND OF THE INVENTION




1. Technical Field of the Invention




The invention relates to an instrumentation for stabilizing certain vertebrae of the spine.




2. Prior Art




Instrumentations are known whose aim is to stabilize the spine after surgical treatment of spinal problems. Many of these instrumentations include rods positioned parallel to the spine that carry pedicle screws via a connector. For instance, the EP-A-0 923 908 (Lange) is directed to an instrumentation having a C-clamp that has a jaw at one end thereof which can be quickly and efficiently tightened about a smooth rod. The C-clamp carries a pedicle screw along the rod for coarse positioning and having a means to permit a pivoting movement between the pedicle screw and a connector for fine adjustment while maintaining a fixed reference distance between the rod and the pedicle screw pivot point at all times.




WO98/43551 (Chopin et al) discloses an instrumentation comprising a connector for fastening a rod to a bone-anchoring element. The bone-anchoring element has a anchoring support for the rod, inclined with respect to the longitudinal axis of the bone-anchoring element. The connector has a recess which provides at least one support point for the rod.




In all spinal operations the skill of the surgeon is constantly challenged. The repair and reconstruction work that must be done is located next to vital nerve structures and each patient's spine is different in some respect. In order to treat certain spine pathologies, it is oftentimes required to fix one vertebrae with respect to an adjacent or remote vertebrae in a procedure called the spinal fusion or arthrodieses.




OBJECT AND SUMMARY OF THE INVENTION




The instrumentation according to the above noted state of the art fixedly secures the vertebrae together that are on either side of the injured portion of the spine. The instrumentation should restrain the vertebrae from rotation or left to right, back to front, or up and down motions with respect to one another. The vertebrae are fixed in space with respect to one another until fusion occurs, that is the two fixed vertebrae grow together to form one continues form.




A principle objective of the present invention is to provide an instrumentation which further facilitates the use of the instrumentation for surgeons and which nevertheless has few parts. The instrumentation is provided with a connector that has a hook portion adapted to cooperate with a support of the bone-anchoring element for clamping the longitudinal element, said hook portion having at its bottom side a recess for receiving the longitudinal element, said longitudinal element is clamped against said support, whereas the force of the support on the longitudinal element is approximately parallel to the axis of the bone-anchoring element. The instrumentation of the present invention has the advantage, that more force can be applied to the longitudinal element and that it can be manufactured with a lower profile. Furthermore, the instrumentation of the present invention gives the surgeon the option to use composite materials for the longitudinal element which is radiolucent and can be configured to have mechanical properties closer to bone than traditional materials such as titanium or steel. Furthermore, the instrumentation gives the surgeon the option of a lower profile and polyaxiality of the anchoring mechanism in relationship to the longitudinal element.











BRIEF DESCRIPTION OF THE DRAWINGS




Further features of the present invention will become apparent to those skilled in the art to which the present invention relates from reading the following specification with reference to the accompanying drawings, in which:





FIG. 1

is a side view of the instrumentation according to the present invention;





FIG. 2

is another side view of the instrumentation shown in

FIG. 1

;





FIG. 3

is an enlarged perspective view of a portion the instrumentation illustrated in

FIGS. 1 and 2

;





FIG. 4

is an exploded side elevation of several components of the instrumentation according to the present invention;





FIG. 5

is a side view partly in section of the components shown in

FIG. 4

in there assembled relationship;





FIG. 6

is an exploded side elevation of several components of the instrumentation according to another embodiment of the present invention;





FIG. 7

is a side view partly in section of the components shown in

FIG. 6

in there assembled relationship;





FIG. 8

is an exploded side elevation of several components of the instrumentation according to another embodiment of the present invention;





FIG. 9

is a side view partly in section of the components shown in

FIG. 8

in there assembled relationship;





FIG. 10

is an exploded side elevation of several components of the instrumentation according to another embodiment of the present invention;





FIG. 11

is a side view partly in section of the components shown in

FIG. 10

in there assembled relationship;





FIG. 12

is a perspective view of a cross connector;





FIG. 13

is a vertical cross section of the cross connector according to

FIG. 12

;





FIGS. 14



a


to


18




a


and


14




b


to


18




b


illustrate different stages of the cross connector according to

FIGS. 12 and 13

, during its assembly in situ, that is during the surgery, and





FIGS. 19



a


and


19




b


overall views showing the relationship of the instrumentation with respect to the spine cord.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) OF THE INVENTION




The instrumentation illustrated in

FIGS. 1

to


5


comprises a pedicle screw


2


, a nut


10


, a connector


6


, a upper slip washer


14


and a lower slip washer


13


. The pedicle screw


2


, from top to bottom (as viewed in FIGS.


1


and


2


), consists of a threaded section


4


, a curvilinear shoulder


38


, a hexagonal nut


5


and a cancellous type thread section


3


. The pedicle screw


2


is received by an opening


7


formed in the connector


6


. The nut can be a break-away nut


63


′ as seen in

FIGS. 14



b


to


18




b.


This nut


63


′ has a upper part


63





a


(

FIG. 15



b


) that is broken off after the nut


63


′ has been clamped as seen in

FIG. 16



b.






The connector


6


is comprised of a hook portion


11


having a recess to grasp a smooth round spinal stabilizing rod


1


. The hook portion two opposing ridges


8


and


9


, which have a distance to each other, which is shorter than the diameter of the rod


1


. The two ridges


8


and


9


provide snap-on means when the rod


1


is moved into the recess.




The lower washer


13


is slipped over the thread section


4


and rests against an upper surface


38


adjacent to a hexagonal nut


5


. The lower washer


13


has a peripheral upper concave surface


13




a


and remains longitudinally stationary with respect to the pedicle screw


2


. The slip upper washer


14


is also slipped over the thread


4


. Washer


14


engages lower slip washer


13


and has a bottom convex surface


14




a


for engagement with the concave surface


13




a.


As

FIG. 5

shows, the surfaces


13




a


and


14




a


can slide with respect to one another about a center point P. An upper surface


14




b


rests against a horseshoe shape surface


16


of the connector


6


. A flange


15


at the periphery of the surface


16


supports the slip washer


14


.




The rod


1


is permitted to slide longitudinally with respect to the pedicle screw


2


prior to tightening. After the rod


1


is located, the nut


10


is tightened and the rod


1


is clamped and secured between the slip washer


14


and the connector. As seen in

FIGS. 2 and 5

, the rod


1


rests on the surface


14




b


of the slip washer


14


. The force of the slip washer


14


on the rod


1


is approximately parallel to the axis D as indicated in

FIG. 5

with the arrow


17


. As the force is approximately parallel to the axis D, more force can be exerted on the rod


1


compared with an another direction of a force exerted on the rod


1


. This enables to apply more clamping force to the rod


1


and to manufacture the connector small and with a very low profile. Furthermore a polyaxial configuration is possible, which enables to pivot the connector


6


about point P in all directions as seen in FIG.


5


.




The embodiment according to

FIGS. 6 and 7

comprises a pedicle screw


30


having thread sections


31


and


33


and there between a widening or support


32


. The support


32


has an upper surface, which is perpendicular to the axis of the pedicle screw


30


and which rests against a surface


43


at the bottom of a connector


34


. Two opposing flats


41


for engagement with a not shown tool are formed near the surface


42


. The connector


34


has an opening


36


for receiving the thread section


31


, a hook portion


39


and a supporting flange


40


. The hook part


39


is provided with a recess


35


that receives the rod


1


as seen in FIG.


7


. The rod


1


is clamped between the support


32


and the connector


34


wherein the force of the support on the rod


1


is parallel to the axis D. The support


32


engages the rod


1


at a point


44


at the lower side of the rod


1


. This embodiment does not enable a pivoting movement of the pedicle screw


30


, but as no washers are needed, it has fewer parts and is strong and compact.





FIGS. 8 and 9

disclose an embodiment that comprises a pedicle screw


30


as described above, a nut


37


and a connector


50


. The connector


50


has an opening


51


, a hook part


52


and a recess


53


for receiving a rail


54


that has a rectangular cross section as seen in FIG.


9


. The surface


42


engages the rail


54


at a lower side


54




a


and the force applied on the rail


54


has a direction that is parallel to the axis D of the pedicle screw


30


, as indicated in

FIG. 9

with arrow


58


. The rail is made of stainless steel, titanium or plastic and preferably a composite material containing long carbon fibers.




The embodiment according to

FIGS. 10 and 11

is similar to that disclosed in

FIGS. 8 and 9

but is provided with a lower washer


56


and a slip washer


55


and does enable a pivoting movement of the pedicle screw


2


.





FIGS. 12

to


19


disclose a transverse connector


60


for connecting two rods


1


. The connector


60


includes a pair of fixing means


62


and a transverse element


61


connecting the fixing means


62


. The transverse element


61


has in a distance to each other two recesses


75


each receiving a nut


63


and a pair of openings


77


each receiving a foot element


65


. Each fixing means


62


comprises an upper clamping element


64


that has at its upper side a tapered recess receiving a corresponding connecting part


79


formed at the transverse element


61


. At the tapered outer surface of the connecting part


79


a circumferential rip


72


is formed, that engages a corresponding groove


80


of the clamping element


64


. Each clamping element


64


is rotatably fixed at the transverse element


61


.




Each of the foot elements


65


comprises a clamping part


67


having a recess


68


for receiving a rod


1


, a rod like grip


66


and an elevated surface


70


engaging a surface


71


at the lower side of a clamping element


64


.




The transverse connector


60


is attached to the rods as illustrated in

FIGS. 14

to


19


. In

FIG. 14

, the two rods


1


are fixed to the spine with pedicle screws or any other bone-anchoring element and connectors as disclosed above. At least one rod


1


can also be a rail


54


or any other longitudinal element suitable to connect two vertebrae. The nuts


63


and the transverse element


61


are positioned as seen in FIG.


14


. The recesses


68


and


69


are spaced apart and the foot elements


65


are pivotable at a point located above the transverse element


61


.



Claims
  • 1. An instrumentation for stabilizing certain vertebrae of the spine with respect to one another in a portion of the spine to be treated, the instrumentation comprising:a spinal stabilizing longitudinal element that is adapted to be placed in a generally parallel relationship with the portion of the spine to be treated; a bone-anchoring element; a connector having an opening therethrough, said opening having dimensions greater than a cross-section dimension of a machine thread section of said bone-anchoring element; a mechanism adapted to affix said bone-anchoring element in said opening; said mechanism comprising a pressure element received by said bone-anchoring element; wherein said connector has a hook portion adapted to cooperate with a support of the bone-anchoring element for clamping the longitudinal element; said hook portion having at a bottom side thereof a recess for receiving the longitudinal element; wherein said hook portion is provided with snap-on means when the longitudinal element is moved into the recess; wherein when said longitudinal element is clamped against an upper surface of said support said upper surface is perpendicular to an axis of the bone-anchoring element and a force of the support and the connector on the longitudinal element is approximately parallel to the axis of the bone-anchoring element.
  • 2. An instrumentation according to claim 1, wherein the longitudinal element engages a washer received by said bone-anchoring element and arranged between said connector and said support.
  • 3. An instrumentation according to claim 2, wherein the washer has an opening therethrough, said opening having dimensions greater than a cross-section dimension of said bone-anchoring element.
  • 4. An instrumentation according to claim 2, wherein said connector has on a bottom side thereof a recess adapted to receive a section of the washer.
  • 5. An instrumentation according to claim 2, wherein the washer is a slip washer.
  • 6. An instrumentation according to claim 1, comprising a transverse connector located between a first and a second longitudinal element;said transverse connector comprising a transverse element and a first and a second fixation means for connecting the transverse element to said first and second longitudinal element: said first and second fixation means comprising an first and upper clamping part and a second part; said second part having a foot part clamped against a bottom side of the longitudinal element.
  • 7. An instrumentation according to claim 6, wherein the foot part has a grip received in a opening of said first and upper clamping part.
  • 8. An instrumentation according to claim 7, wherein said grip has a recess adapted to break at a predetermined force.
Priority Claims (1)
Number Date Country Kind
01810401 Apr 2001 EP
US Referenced Citations (9)
Number Name Date Kind
5108399 Eitenmuller et al. Apr 1992 A
5486174 Fournet-Fayard et al. Jan 1996 A
5498263 DiNello et al. Mar 1996 A
5601554 Howland et al. Feb 1997 A
6004349 Jackson Dec 1999 A
6086588 Ameil et al. Jul 2000 A
6234705 Troxell May 2001 B1
6283967 Troxell Sep 2001 B1
6368320 Le Couedic et al. Apr 2002 B1
Foreign Referenced Citations (8)
Number Date Country
0 384 001 Aug 1990 EP
0 590 745 Apr 1994 EP
0 923 908 Jun 1999 EP
2 615 095 Nov 1988 FR
2 702 361 Sep 1994 FR
2 765 093 Dec 1998 FR
WO 9428831 Dec 1994 WO
WO 9843551 Oct 1998 WO