Orthopedic implant kit

Abstract

An orthopedic implant kit comprising a lockable poly-axial screw, a tissue dilatation sleeve, a screw driver, a screw extender, a rod, rod-reduction device, a set screw driver, a torque limiting device and a screw releasing device.

Claims

1. An orthopedic screw extender comprising: a hollow longitudinal body including two opposite longitudinal slots, a distal part of the hollow longitudinal body having an engagement mechanism configured to receive a screw head by an upwardly pressure on the screw head in a direction of a main axis of the hollow longitudinal body towards the hollow longitudinal body, and configured to separate from the screw head by a downward pressure on the screw head away from the hollow longitudinal body; and a screw release instrument having an external thread, wherein the hollow longitudinal body includes an internal thread, the internal thread configured to threadably engage with the external thread of the screw release instrument to provide the downward pressure to the screw head.

2. The screw extender according to claim 1, the engagement mechanism includes a longitudinal ridge or a longitudinal groove arranged in parallel to the main axis at the distal part of the hollow longitudinal body, dimensioned to receive a corresponding longitudinal groove or longitudinal ridge, respectively, of the screw head.

3. The screw extender according to claim 1, wherein the hollow longitudinal body is configured to threadably engage by the internal thread with an external thread of a multi-use instrument or a threading of a set screw inside the hollow longitudinal body.

4. The screw extender according to claim 1, wherein the engagement mechanism is configured to guide the screw head during an insertion to the screw extender along the direction of the main axis of the screw extender.

5. The screw extender according to claim 1, wherein the hollow longitudinal body is made of one piece of elastic material.

6. The screw extender according to claim 1, wherein the engagement mechanism is configured such that the downward pressure on the screw head by the screw release instrument progressively separates the screw head from the screw extender.

7. The screw extender according to claim 1, wherein the engagement mechanism is configured such that the downward pressure on the screw head by the screw release instrument progressively separates the screw head from the screw extender without laterally expanding the screw extender.

8. An implant kit having the orthopedic screw extender according to claim 1.

9. The screw extender according to claim 1, wherein the two opposite longitudinal slots include an open end towards the distal part of the hollow longitudinal body.

10. An orthopedic pedicle screw holding and releasing system comprising: a longitudinal screw holding means including two opposite longitudinal slots and an internal threading means, an end of the longitudinal screw holding means having an attachment means for holding a pedicle screw, the pedicle screw inserted to the attachment means by an engaging pressure on the pedicle screw in a direction towards the longitudinal screw holding means, and for separating from the pedicle screw by a releasing pressure on the pedicle screw away from the longitudinal screw holding means; and a screw release means having an external threading means, wherein the internal threading means of the longitudinal screw holding means and the external threading means of the screw release means are configured for threadably engaging with each other to provide the releasing pressure to the pedicle screw by the screw release means.

11. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the attachment means includes a longitudinal ridge or a longitudinal groove arranged in parallel to a main axis of the longitudinal screw holding means, dimensioned to receive a corresponding longitudinal groove or longitudinal ridge, respectively, of the pedicle screw.

12. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the longitudinal screw holding means is configured for threadably engaging by the internal threading means with an external threading of a multi-use instrument or a threading of a set screw inside the longitudinal screw holding means.

13. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the attachment means is configured for guiding the pedicle screw during the insertion to the longitudinal screw holding means along a direction of a main axis of the longitudinal screw holding means.

14. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the longitudinal screw holding means is made of one piece of elastic material.

15. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the attachment means is configured such that the releasing pressure on the pedicle screw by the screw release means progressively separates the pedicle screw from the longitudinal screw holding means.

16. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the attachment means is configured such that the releasing pressure on the pedicle screw by the screw release means progressively separates the pedicle screw from the longitudinal screw holding means without laterally expanding the longitudinal screw holding means.

17. The orthopedic pedicle screw holding and releasing system according to claim 10, wherein the two opposite longitudinal slots include an open end towards the end of the longitudinal screw holding means.

18. An implant kit having the orthopedic pedicle screw holding and releasing system according to claim 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The invention will be better understood in the following part of this document, with non-limiting examples illustrated by the following figures:

(2) FIG. 1 shows an implant kit according to the invention

(3) FIG. 2 shows an example of a lockable poly-axial pedicle screw according to the invention

(4) FIGS. 3A to 3C are cross-sections and partial cut views of the screw of FIG. 2

(5) FIG. 4 represents different views (complete and partial) of the screw of FIG. 2

(6) FIG. 5 shows the distal part of a screw extender according to the invention, together with the screw of FIG. 2

(7) FIG. 6 is a cross section of the screw extender distal part

(8) FIG. 7 is a global view of a screw extender with a screw

(9) FIGS. 8A to 8C represent the positioning of the rod in the screw head, rod reduction and the tightening of the set screw

(10) FIGS. 9A to 9C illustrate the release of the screw with respect to the screw extender

(11) FIG. 10 shows a screw extender which includes a mechanism for laterally expanding the screw extender distal part

(12) FIG. 11 is another representation of the screw extender of FIG. 10

(13) FIG. 12 shows another embodiment of a pedicle screw according to the invention

(14) FIGS. 13A to 13C show different views of a rotatable shaft which is used in a rod reduction instrument, a set screw driver and a screw releasing instrument

(15) FIGS. 14 and 15 illustrate a torque limiting mechanism

(16) FIGS. 16 and 17 show the use of a tissue dilatation sleeve

(17) FIGS. 18 to 38 show a procedure using an implant kit according to the invention

NUMERICAL REFERENCES USED IN THE FIGURES

(18) 1. Pedicle screw 2. Head 3. Set screw 4. Threaded portion 5. Locking element 6. Screw extender 7. Rod 8. Multi-use instrument upper part 9. Tissue dilatation sleeve 10. Torque driver 11. Head passage 12. Threaded portion passage 13. Branch 14. Cylindrical body 15. Slot 16. Cylindrical body distal part 17. Ridge 18. Groove 19. Screw extender internal threaded part 20. Multi-use instrument lower part 21. Conical part 22. Blade 23. Half tube 24. Screw driver 25. Handle 26. Multi-use instrument (Rod reduction/Set screw driver/screw release) 27. Rod inserting instrument 28. Breakable pin 29. Lateral pin 30. Circular groove 31. Puncturing needle/Guide wire 32. Concave screw top 33. Convex upper half ball

(19) The examples below more precisely relate to a thoracolumbar fusion system consisting of pedicle screws and rods combined with single use instruments. A typical pedicle screw system consists of the screw implants and the instruments for placing the screws.

(20) FIG. 1 shows an example of an implant kit according to the invention.

(21) This kit contains a tissue dilatation sleeve 9, a handle 25, a rod 7, a rod inserting instrument 27, a shaft 26 which can be used as a rod reduction instrument and/or a set screw driver and/or a screw releasing instrument, a pedicle screw 1, a screw extender 6 and a screw driver 24.

(22) The lockable poly-axial screw 1 illustrated in particular in FIGS. 2 to 4 includes a head 2 and a threaded portion 4. FIG. 2 also shows a set screw 3 which may be fixed to the head after the insertion of a rod 7. The screw 1 furthermore comprises a locking element 5 having a U-shape. When the locking element 5 is fully inserted in the screw head 2 the orientation of threaded portion 4 is blocked with respect to the head 2. Inversely, when the locking element is retrieved, the threaded portion 4 can be freely oriented with respect to the screw head 2.

(23) The lockable poly-axial screw according to the invention may therefore be transformed into a mono-axial screw, thus allowing having mono-axial and poly-axial capability in the same product. A blocking system defined previously allows the surgeon to choose if he/she wants to use the screw in mono-axial or poly-axial mode. As mentioned mono-axial capability is achieved by pushing the locking element (clip) 5 and poly-axial capability is achieved by removing the clip 5. The clip 5 is just an example of a blocking system; other technical solutions can also be imagined such as a pin.

(24) Preferably, in the mono-axial mode the head may still freely rotate around its own axis, with respect to the threaded portion. Such a mechanism may be obtained with a U-shape clip and with an annular groove located around the upper part of the threaded portion. In this case the branches of the clip are sliding within the annular groove.

(25) Any orientation of the axis can be considered when the mono-axial is used, i.e. the screw axis and the screw head may be oriented along different directions.

(26) FIGS. 5 to 7 represent the attachment of a pedicle screw 1 to the distal end 16 of a screw extender 6, by inserting the screw head 2 within the distal end 16. In this operation the head 2 is guided with a lurality of ridges 17 located within the distal end 16 and grooves located on the head 2. With such a system the screw head is better retained within the screw extender 6.

(27) Any suitable material can be used for the screw extender 6 (plastic, polymer, metal, etc . . . ).

(28) FIGS. 8A to 8C represent the positioning of the rod 7 in the screw head 2, a rod reduction and the tightening of the set screw 3 in the screw head 2.

(29) The multi-use instrument 26 (see also FIGS. 13A to 13B) is defined by an upper part 8 and a lower (threaded) part 20.

(30) The rod 7 may be pushed downwards by rotating the multi-use instrument 26 within the cylindrical body 14.

(31) After the rod insertion within the head 2, the set screw 3 is fixed to the head 2 by further rotating the multi-use instrument 26.

(32) The multi-use instrument 26 is also provided with a torque limiting mechanism (see FIGS. 14 and 15). When the set screw 3 is fixed within the head 2 and the multi-use instrument 26 further rotated, the torque increases, up to a point where the pin 28 breaks. A further rotation of the multi-use instrument 26 has therefore no more effect on the set screw 3. From that point the further rotation of the multi-use instrument 26 only induces a downwards pressure on the screw head 2. The screw 1 is therefore progressively separated from the screw extender (see FIGS. 9A to 9C).

(33) This screw releasing mechanism from an instrument offers the possibility to release the screw 1 from the screw extender without laterally expanding the screw extender 6.

(34) It should be mentioned at this stage that this mechanism is not limited to the release of pedicle screws. Any other item may be used.

(35) To summarize, the same instrument 26 can be used for rod reduction, for fixing a set screw to a screw head and for releasing a screw from a screw extender.

(36) It should be underlined that the invention is not limited to this triple use of the same instrument. A double use is also comprised, for instance rod-reduction and fixation of the screw set to the screw head.

(37) FIGS. 10 and 11 show an alternative solution to attach a pedicle screw to an screw extender, by rotating an inside tube (not illustrated) the half-tubes 23 are expanded by their own elasticity. This allows a screw to be inserted and fixed to it by for example clamping the outer surface around the screw. The same principle can be used as an alternative to detach the screw extender from a screw.

(38) The clamping system also achieves part of its rigidity, by resting on support surfaces on the screw head.

(39) FIG. 12 shows a concave screw top 32, inside a convex upper half ball 33, allowing the rod 7 and the set screw 3 to be set lower in the screw head 2, thus decreasing the total build height, and increasing the strength and rigidity of the system.

(40) FIGS. 16 and 17 represents a tissue dilatation sleeve 9 containing four triangular flexible blades 22 intervened into each other and forming a cone 21. The cone 21 is mounted at the tip of a screw extender 6, with a tear off spiral. This allows the tissue to be pushed aside as the screw extender 6 is inserted into a body. Once in place, the surgeon may remove the sleeve 9 while the screw extender remains in the body. Any suitable number of blades can be used for forming the cone.

(41) FIGS. 18 to 38 show a procedure using the items which have been previously presented.

(42) In a first step (FIGS. 18 and 19) two puncturing guide wires 31 are positioned in the spine.

(43) A first screw extender 6 with a screw 1 attached and surrounded by a dilatation sleeve is then inserted through the tissue (FIGS. 20 and 21), and along the guide wire 31. The screw extender 6 is rotated and/or pushed.

(44) A similar operation is carried out with a second screw extender 6 and screw 1 (FIGS. 22 and 23).

(45) A screw driver 24 is inserted within the screw extender 6. Its distal end is introduced within the upper part of the screw threaded portion 4. The screws 1 are then rotated and enter the vertebrae (FIGS. 24 and 25).

(46) The tissue dilatation sleeves 9 are removed (FIGS. 26 to 28).

(47) A rod inserting instrument 27 with a rod 7 at its end is transversally crossing the tissue (FIGS. 29 and 30).

(48) The rod 7 is positioned above the screw head 2 (FIG. 32) and the multi-use instrument 26 is introduced within the screw extender 6, to such an extent that the set screw 3 is positioned above the rod 7, in line with the screw head 2 (FIGS. 31 and 32).

(49) FIGS. 33 to

(50) 36 show the rod placement within the screw heads 2 and the fixation of the set screw 3 within the screw head 2.

(51) FIGS. 37 and 38 illustrate the screw release from the screw extender 6 and the screw 1, the rod 7 and the screw set 3 in their definitive location.

(52) The invention is of course not limited to those illustrated examples.

(53) The screw extender according to the invention may be used with mono-axial, poly-axial or lockable poly-axial screws.