INJECTION DEVICE SUITABLE FOR INJECTING PARTICLES INTO A BONE CAVITY

Abstract

An injection device for injecting particles into a bone cavity includes a reservoir, an injection needle having a tubular shape around a main axis and a proximal end fixed to a base of the reservoir and open to the reservoir, and a distal end opposite to the proximal end, a worm screw movable in rotation inside the injection needle and extending at least from the proximal end up to at least the distal end of the injection needle, and an actuator coupled to the worm screw to drive it in rotation.

Claims

1. An injection device adapted for injecting particles into a bone cavity, said injection device comprising: a reservoir capable of containing at least in part the particles; an injection needle having a tubular shape around a main axis and provided with a proximal end fixed to a base of the reservoir and open to the reservoir, and an distal end opposite to the open proximal end; a worm screw movable in rotation around the main axis inside the injection needle and extending at least from the proximal end up to at least the distal end of the injection needle; and an actuator coupled to the worm screw to drive the worm screw in rotation.

2. The injection device according to claim 1, wherein the actuator comprises a shaft coupled in rotation to the worm screw, said shaft emerging from the reservoir to be engaged with a motor.

3. The injection device according to claim 1, wherein a piston is slidably mounted in the reservoir and is movable in translation according to the main axis.

4. The injection device according to claim 1, comprising at least one dispersion means capable of dispersing and suspending the particles in a liquid or gel composition, inside the reservoir.

5. The injection device according to claim 4, wherein the dispersion means is selected from among the following or a combination of all or part of the following: an introduction system for introducing the liquid or gel composition inside the reservoir, said introduction system comprising a circulation means located outside the reservoir and ensuring a circulation of the liquid or gel composition in one or several introduction conduits connected to one or several introduction points opening into the base of the reservoir; a vibrator system for applying a vibration to the reservoir or to the injection needle: a stirring system for stirring the particles dissolved in the liquid or gel composition inside of the reservoir; and an oscillating system comprising a piston slidably mounted in the reservoir and movable in translation according to the main axis, and an oscillating actuator capable of imparting an oscillating movement to the piston according to the main axis.

6. The injection device according to claim 1, wherein the worm screw has a generally cylindrical shape or a generally frustoconical shape.

7. The injection device according to claim 1, wherein the worm screw extends beyond the proximal end of the injection needle, such that the worm screw has at least two successive portions comprising: a lower portion which extends from the proximal end up to the distal end of the injection needle; and an upper portion which prolongs the lower portion beyond the proximal end and which extends inside the reservoir.

8. The injection device according to claim 1, wherein the worm screw is adjustable in translation along the main axis.

9. The injection device according to claim 1, further comprising an expandable implant comprising at least one catheter and an expandable envelope that may be configured between: a contracted state in which the expandable envelope is radially constrained in the catheter for delivery of the expandable envelope within the bone cavity (90), and a deployed state in which the expandable envelope is extended out of the catheter with a bag configuration to be filled with particles.

10. The injection device according to claim 9, wherein the expandable envelope includes at least a plurality of threads arranged to form together a mesh, or the expandable envelope is a solid expandable envelope made of an elastic or inflatable material.

11. The injection device according to claim 9, wherein the catheter passes through the worm screw.

12. An injection kit comprising at least: an injection device according to claim 1; and particles adapted to be injected inside a bone cavity by said injection device.

13. The injection kit according to claim 12, further comprising a bone vibrator capable of applying a vibration to a bone during an injection of the bone cement composition into a bone cavity of said bone.

14. The injection kit according to claim 12, wherein the worm screw has a screw pitch greater than or equal to a maximum particle size.

15. The injection kit according to claim 12, wherein the particles are selected from particles of hydroxyapatite, poly(lactic-glycolic)acid, starch or chitosan.

16. The injection kit according to claim 12, wherein the particles are dissolved in a liquid or gel composition to form together a bone cement composition, wherein said liquid or gel composition includes a liquid or gel solvent adapted to diffuse through the bone.

17. The injection kit according to claim 16, wherein the liquid or gel composition is a polymeric gel comprising a polymer dissolved in a solvent, said polymer being selected from: polyethylene glycol, hyaluronic acid or hydroxypropyl methylcellulose dissolved in water; ethylene vinyl alcohol or cellulose acetate dissolved in dimethyl sulfoxide; and ethyl cellulose dissolved in ethanol.

18. The injection kit according to claim 16, wherein the liquid or gel composition is a biological glue which is selected from biological glues based on: fibrinogen or thrombin, fibrinogen and thrombin being optionally in association with aprotinin, autologous fibrin, collagen, or N-butyl-cyanoacrylate.

19. The injection kit according to claim 16, wherein the liquid or gel composition comprises a radiopaque agent, which is for example an ethiodized oil or a micronized metal powder selected from powders of tantalum, tungsten, barium, bismuth, mineral iodine, or a gadolinium solution of ethylenediaminetetraacetic acid.

20. The injection kit according to claim 16, wherein the ratio of the mass percentage of the liquid or gel composition to the mass percentage of particles is at most 1:4.

21. The injection kit according to claim 16, wherein the bone cement composition further comprises fibers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The disclosure will be better understood with the aid of the detailed description which is disclosed hereinbelow with reference to the appended figures representing, as a non-limiting example, several embodiments of an injection device according to disclosure, as well as an illustration of an expandable implant adapted to the disclosure.

[0082] [FIG. 1] is a schematic illustration of an injection kit according to a first embodiment of the disclosure, comprising a first injection device and a bone cement composition, wherein the first injection device is in a first configuration;

[0083] [FIG. 2] is a schematic illustration of the injection kit of FIG. 1, wherein the first injection device is in a second configuration;

[0084] [FIG. 3] is a schematic illustration of an injection kit according to a second embodiment of the disclosure, comprising a second injection device and a bone cement composition; and

[0085] [FIG. 4] is a schematic illustration of an expandable implant adapted to the disclosure, during successive steps (a) to (g) of inserting its expandable envelope inside a bone cavity.

DETAILED DESCRIPTION OF THE DRAWINGS

[0086] Referring to FIGS. 1 to 3, an injection kit comprises particles and an injection device 1 adapted to inject the particles inside a bone cavity 90 of a bone 9. For the Following description, with regard to the injection device 1, the same numerical references will be used to refer to components or elements that are identical, similar or having identical functions.

[0087] In an advantageous embodiment, the particles are dissolved in a liquid or gel composition to form together a bone cement composition 10, where this liquid or gel composition includes a liquid or gel solvent adapted to diffuse through the bone 9.

[0088] The bone cement composition 10 therefore comprises at least the particles dissolved in the liquid or gel composition which is a biological glue or a polymeric gel, with a ratio of the mass percentage of the polymeric gel or of the biological glue to the mass percentage of particles which is at most 1:4.

[0089] The particles are selected from particles of hydroxyapatite, poly(lactic-glycolic)acid (hereinafter abbreviated as PLGA), starch or chitosan.

[0090] The polymer gel comprises a polymer dissolved in a solvent, where the polymer is selected from: [0091] polyethylene glycol, hyaluronic acid or hydroxypropyl methylcellulose dissolved in water; [0092] ethylene vinyl alcohol or cellulose acetate dissolved in dimethyl sulfoxide; [0093] ethyl cellulose dissolved in ethanol.

[0094] The biological glue is selected from biological glues based on: [0095] fibrinogen or thrombin, fibrinogen and thrombin being optionally in association with aprotinin, [0096] autologous fibrin, [0097] collagen or [0098] N-butyl-cyanoacrylate.

[0099] The bone cement composition 10 optionally comprises a radiopaque agent such as a micronized metal powder selected from tantalum, tungsten, barium, bismuth, or mineral iodine powders. Alternatively, the radiopaque agent may be a gadolinium solution of ethylenediaminetetraacetic acid or an ethiodized oil.

[0100] The following description relates to the injection device 1, whether in the first embodiment illustrated in FIGS. 1 and 2 or in the second embodiment illustrated in FIG. 3. The injection device 1 comprises a reservoir 2 capable of containing the bone cement composition 10, where this reservoir 2 has a base 20 (forming a bottom wall) in the lower portion and has a top 21 (open or closed by a removable lid or not) in the upper portion. The reservoir 2 may has a generally cylindrical shape.

[0101] In the example of FIG. 3, the injection device 1 also comprises an attached reservoir 22 which is fixed to the reservoir 2 and which receives particles internally, and in particular bulk particles, where these particles are those used to form the bone cement composition 10. This attached reservoir 22 is in communication with the reservoir 2 through an opening 23, and for example an opening provided with a configurable flap between an open position (for an opening of the communication) and a closed position (for a closing of the communication). Thus, the particles may be introduced gradually into the reservoir 2. It could be considered that this reservoir 2 is filled beforehand (and possibly continuously supplied) with biological glue or polymeric gel, just as it could be considered that this reservoir 2 only contains the dry particles in the case where the particles are introduced without a liquid or gel composition.

[0102] The injection device 1 comprises an injection needle 3 of tubular shape around a main axis AP and provided with a proximal end 30 fixed to the base 20 of the reservoir 2 (for example by means of a connection socket) and open to the reservoir 20, and an open distal end 31 opposite the proximal end 30. The proximal end 30 is thus in fluid connection with the interior of the reservoir 20, and the distal end 31 is provided to penetrate inside the bone cavity 90. The distal end 31 may be provided with a pointed or beveled tip, to pierce the compact and hard outer layer 92 of the bone 9; optionally after pre-piercing of this outer layer 92.

[0103] The injection device 1 comprises a worm screw 4 movable in rotation around the main axis AP inside the injection needle 3 and extending at least from the proximal end 30 up to at least the distal end 31 of the injection needle 3. This worm screw 4 is thus mounted inside an inner channel of the injection needle 3; this inner channel having a generally cylindrical shape. The worm screw 4 has a generally cylindrical shape (as illustrated in FIG. 1) or a generally tapered shape (in a non-illustrated variant). This worm screw 4 has a maximum outer diameter which is substantially less than an inner diameter of the inner channel of the injection needle 3, for mounting almost without a clearance of the worm screw 4 in the inner channel of the injection needle 3; a clearance being provided to allow the worm screw 4 to rotate inside the inner channel of the injection needle 3.

[0104] The worm screw 4 has a screw pitch greater than or equal to a maximum particle size of the bone cement composition 10, and for example a screw pitch equal to or greater than 2 millimeters.

[0105] In a not illustrated embodiment, the worm screw 4 extends from the proximal end 30 up to the distal end 31 of the injection needle 3, and thus has a length (distance measured along the axis of rotation of the worm screw 4) substantially equivalent to the length of the injection needle 3.

[0106] In the embodiments of FIGS. 1 and 2 and FIG. 3, the worm screw 4 extends from the proximal end 30 up to the distal end 31 of the injection needle 3, and also extends beyond the proximal end 30 such that this worm screw 4 extends in part inside the reservoir 2. In other words, the worm screw 4 has two successive portions: [0107] a lower portion 43 which extends from the proximal end 30 up to the distal end 31 of the injection needle 3, and thus has a length substantially equivalent to the length of the injection needle 3; [0108] an upper portion 44 which prolongs the lower portion 43 and which extends inside the reservoir 2.

[0109] Moreover, the worm screw 4 is adjustable in translation along the main axis AP, and this worm screw 4 is thus configurable between: [0110] a first configuration, visible in FIG. 1, in which the worm screw 4 is retracted inside the injection needle 3, in the way that this worm screw 4 does not protrude from the distal end 31 of the injection needle 3; and [0111] a second configuration, visible in FIG. 2, in which the worm screw 4 is deployed out of the injection needle 3, in the way that this worm screw 4 protrudes from the distal end 31 of the injection needle 3 to be immersed inside the bone cavity 90.

[0112] Preferably, this adjustment is controlled in the way that the projecting length of the worm screw 4, beyond the distal end 31 of the injection needle 3, is controlled and lockable, which means that the surgeon may adjust and block this projecting length.

[0113] Although not shown, it also could be considered that the worm screw 4 of FIG. 3 is also adjustable in translation along the main axis AP.

[0114] The worm screw 4 has the function of guiding and conveying the particles of the bone cement composition 10 from the reservoir 2 up to the distal end 31 of the injection needle 3, and therefore up to the bone cavity 90 of the bone 9. In the example of FIG. 1, this guiding and this conveying of the particles by the worm screw 4 take place from the proximal end 30 of the worm needle 3, therefore from the base 20. In the example of FIG. 2, this guiding and this conveying of the particles by the worm screw 4 take place from inside the reservoir 2, by means of the upper portion 44 of the worm screw 4 which begins to convey the particles while providing stirring due to the rotation of this upper portion 44 in the reservoir 2 which generates a swirling flow.

[0115] In the embodiment of FIG. 3, the upper portion 44 of the worm screw 40 may have a diameter greater than that of the lower portion 43, and it is in particular possible that this upper portion 44 has an increasing diameter from the lower portion 43. In the embodiment of FIGS. 1 and 2, the upper portion 44 of the worm screw 40 has the same diameter as the lower portion 43.

[0116] The injection device 1 comprises an actuator 40 coupled to worm screw 4 to drive it in rotation. In the non-limiting example illustrated in FIG. 1, the actuator 40 comprises a motor 41 engaged with a shaft 42, where this shaft 42 is coupled in rotation to the worm screw 4, and in particular the shaft 42 has a lower portion around which the worm screw 4 is fixed. The shaft 42 comes out of the reservoir 2 to be engaged with the motor 41 placed outside the reservoir 2.

[0117] In the case where the worm screw 4 is adjustable in translation along the main axis AP, then the actuator 40, and therefore the motor 41 and the shaft 42, are secured in translation to the worm screw 4.

[0118] The injection device 1 comprises a piston 5 which is slidably mounted in the reservoir 2 and movable in translation according to the main axis AP. This piston 5 is crossed in a sealed manner by the shaft 42.

[0119] It may be considered that this piston 5 is screwed on the periphery of the shaft 42, which allows an advance of the piston 5 in proportion to the volume evacuated by the worm screw 4 inside the bone cavity 90. In this case, the piston 5 must be able to rotate and thus the actuator 40 must be adapted so that the piston 5 can move in a spiral.

[0120] The injection device 1 also comprises one or several dispersion means capable of dispersing and suspending the particles of the bone cement composition 10 in the biological glue or the polymeric gel inside the reservoir 2.

[0121] A first dispersion means is an introduction system 6 for introducing a biological glue or polymeric gel inside the reservoir 2, where this introduction system 6 comprises a circulation means 60 (like for example a fluidic pump) located outside the reservoir 2 and providing circulation of biological glue or polymeric gel in one or several introduction conduits 61 connected to one or several introduction points 62 opening into the base 20 of the reservoir 2.

[0122] This introduction system 6 may for example be supplemented with a recirculation system for recirculation of the biological glue or the polymer gel, which comprises one or several evacuation points 63 opening into the reservoir (preferably in the upper portion of the reservoir2) and connected to one or several evacuation conduits 64 for a return of the biological glue or the polymeric gel at the level of the circulation means 60. Thus, the biological glue or the polymeric gel enters at the level of the introduction point(s) 62, and the biological glue where the polymeric gel comes out at the level of the evacuation point(s) 63, the circulation means 60 ensuring the circulation of the biological glue or of the polymeric gel in the introduction conduit(s) 61 and in the evacuation conduit(s) 64, between the evacuation point(s) 63 and the introduction point(s) 62. The evacuation point(s) 63 and the introduction point(s) 62 may be provided with filters to prevent the passage of the particles inside the conduits 63, 64.

[0123] A second dispersion means is a vibrator system 71 for applying a vibration to the reservoir 2 or to the injection needle 3, such as for example a vibration at a frequency comprised between 0.5 Hz and 10 KHz.

[0124] A third dispersion means is a stirring system 72 for stirring the bone cement composition 10 inside the reservoir 2, and it may comprise a stirrer 73 engaged with a motor (not illustrated) located outside the reservoir 2 via a connecting shaft 74 which passes through a wall of the reservoir 2 or which passes through the piston 5.

[0125] A fourth dispersion means is an oscillating system 8 comprising the piston 5 and comprising an oscillating actuator 80 capable of imparting an oscillating movement to the piston 5 according to the main axis via one or several transmission elements 81 which transmit an oscillating movement generated by the oscillating actuator 90 to the piston 5.

[0126] Referring to FIG. 4, it may be considered to provide that the injection device 1 further comprises an expandable implant 11 comprising at least one catheter 12 and an expandable envelope 13 configurable between: [0127] a contracted state (visible on FIG. 4(a)) in which the expandable envelope 13 is radially constrained in the catheter 12 for a delivery of the expandable envelope 13 within the bone cavity, and [0128] an expanded state (visible in FIGS. 4(c) to 4(g)) in which the expandable envelope 13 is extended out of the catheter 12 with a bag-like configuration.

[0129] This expandable implant 11 thus comprises a tubular thrust member 14 (visible in FIGS. 4(e) and 4(f)) formed of a tubular rod sliding inside the catheter 12 and connected by a ring 15 to the expandable envelope 13, so that the particles (visible in FIGS. 4(d) to 4(g)) can be injected inside the expandable envelope 13 through this tubular thrust member 14.

[0130] The catheter 12 is provided with a proximal end 16 which opens into the bone cavity, and the expandable envelope 13 is deployed while exiting this proximal end 16.

[0131] Although not illustrated, the catheter 12 passes through the worm screw 4, and therefore crosses the shaft 42, along the main axis AP, and the tubular thrust member 14 has an opening in communication with the reservoir 2 to allow the injection of the particles inside the expandable envelope 13 while passing inside the tubular thrust member 14.

[0132] In a first embodiment, the expandable envelope 13 is a self-expanding mesh or grating envelope (which deploys naturally once exiting the catheter 12) which includes at least a plurality of threads arranged to form together a mesh or lattice. In this first embodiment, the mesh has openings (or intermesh spaces), between the threads, the dimensions of which are smaller than the sizes of the particles such that these particles cannot escape from the expandable envelope 13.

[0133] In a second embodiment, the expandable envelope 13 is a solid envelope (not meshed) made of a material that is both biocompatible and elastic or inflatable material; it being noted that this material may be resorbable or non-resorbable. In this second embodiment, the expandable envelope 13 is inflated by injection of the liquid or gel composition (such as the previously described biological glue or polymeric gel) via the interior of the tubular thrust member 14. The injection pressure of the liquid or gel composition will contribute to deploying the expandable envelope 13 inside the bone cavity 90. Once the expandable envelope 13 has been inflated, the particles are injected inside the expandable envelope 13 by passing also inside the tubular thrust member 14.

[0134] Once the expandable envelope 13 is filled with particles (as seen in FIG. 4(f)), the ring 16 is closed or blocked, and the ring 16 is detached from the tubular thrust member 14, thus making it possible to withdraw both the catheter 12 and the tubular pushing member 14, to leave in the bone cavity the expandable envelope 13 filled with particles and closed by the ring 16 (as visible in FIG. 4(g)).