FR2845591A1 - Applicator for projecting growth stimulant onto surface of bone cavity has pressure source and apertured projector cannula inserted into cavity - Google Patents

Abstract

The applicator (1,2) for projecting a material (3) onto the surface of a bone cavity (12) to stimulate bone growth adjacent to an implant has a projector (2) insertable into the bone cavity and a pressure source (6) to drive the material. The projector has a cannula insertable into the bone cavity with apertures facing the bone surface to be treated. The material can be projected by centrifugal force.

Description

DESCRIPTION

  The present invention relates to a method and an apparatus for projecting a material under

  powdery form and adhere it to the walls of a sharpened bone cavity or to a bone section.

  The objective being to deposit in this sharpened bone cavity, or on this bone cut, a pulverulent material 5 by projection and to allow it to adhere to the osseous support before the installation of an implant, preferably cemented, in order to compensate for the chemical or thermal toxicity of the cement by accelerated osteogenesis, thanks to the physicochemical action of the sprayed material, preferably a powder

  mainly crystalline hydroxyapathite or any other material for therapeutic or preventive purposes.

STATE OF THE ART:

  Currently, during bone surgery, the practitioner cleans the bone cavities or bone surfaces called to receive surgical cement. This cleaning is generally done with

  a sterile liquid using a syringe or a device projecting under pressure the said sterile liquid.

  Some surgeons use physiological saline, the disadvantages of which are not only to empty the spongy bone support of its osteogenic cells, but also to dilute the hemostasis in this bone cavity or sharpened bone section. Finally, some surgeons use bone substitutes in the form of granules, of a caliber greater than 1 mm, to cover the areas called upon to receive an implant with cementless fixation. With the methods currently used, the deposition of a bone substitute or of any solid material is made difficult because the blood flow resulting from the sharpening of the bone tends to dilute or expel this material before it becomes fixed in the bone cavity or on the bone surface. On the other hand, it would be advantageous to provide a reliable method making it possible to remedy the perverse effects of surgical cement which, during its polymerization, causes

  an exothermic reaction favoring thermal or chemical necrosis of the bone.

  The method of use and its apparatus according to the invention make it possible to remedy the drawbacks of the current technique by optimizing the projection of the pulverized material and its attachment to the bone support and to eliminate, by depositing a layer on the support. bone, necrosis phenomena

thermal or chemical.

DESCRIPTION:

  The present invention relates to a method and its apparatus (1) (2) consisting of two specific instruments. The first instrument (1) consists of a container acting as a bellows (for example in the form of a pear), and a reservoir containing the cleaning liquid and promoting hemostasis (9 ) (for example, hydrogen peroxide), ending with a nozzle whose length can be variable and allowing the diffusion, in droplets or in small fine jets, of a cleaning and hemostasis liquid ( 9) whose volume is chosen between 2 and 250 ml, so as not to dilute the membrane of clots (consisting of collagen and fibrosis), which has formed by bleeding from the prepared bone area. The tip of the instrument is closed by a closure means (8) in order to avoid any loss of liquid (9) during its transport. The whole, contents and container is packaged in a special sterile packaging which will only be opened during surgical intervention. The second instrument (2) consists of a cannula (5), the variable length of which can be cut on demand, penetrating into the bone cavity. It can also be a sleeve (11) covering the bone cut to be treated. One or the other device 40 is provided, on its portion in relation to the bone to be treated, with a network of holes (4) or slots; these orifices, of dimension slightly greater than that of the gains in the material, will allow the material to be evacuated with sufficient velocity to adhere to the layer of blood clots (10). Said material in powder form (3) must have a particle size between 20 and 400 microns, preferably between 100 and 180 microns. When packaging in its sterile packaging, the said cannula orifices (5) are obstructed to prevent loss of the material during transport. During the surgical procedure, the orifices of the cannula will be released. This cannula (5) or the sleeve (11) contains the material in the form of powder (3) which is to be projected into the bone cavity or onto the bone surface (13). This cannula (5) can also be connected to a reservoir (15) containing the same material (3) as that contained in the cannula (5). The cannula (5) and its possible reservoir (15) or the sleeve (11) are connected to an energy source which will promote the projection of the material (3) in the form of a cloud or a projection. This energy source can be gaseous (6) or mechanical (7). In its gaseous form (6), it is a gas under pressure, in its mechanical form (7), it is, for

  for example, an axis whose rotation favors by centrifugal effect the propulsion of the material (3) to be projected.

METHOD OF USE:

  After preparation and deepening of the cavities (13) or surfaces (13) called to receive the surgical cement, the tip of the first instrument - released from its closure means - is positioned in relation to the bone area to be treated and the liquid (9 ) content of this instrument is projected into the bone cavity (12) or onto the bone cut (13). The liquid (9) sprayed will slow down the blood flow by promoting hemostasis, without however washing the membrane of blood clots (10) formed on the bone support. When this hemostasis is achieved, the cannula (5) of the second instrument (2) - released from its closure means (8) - is introduced into the bone and the content of this instrument (1) is projected into the bone cavity ( 12) or on the bone surface (13) to be treated. The projection of the material (3), bone substitute or hydroxyapatite or another filling material or any other material for therapeutic or preventive objective, in powder form, is carried out under pressure thanks to the energy source used - gas (6) or mechanical (7). In its pulverulent form, the material (3), bone substitute or hydroxyapatite or filling material or any other material for therapeutic or preventive purposes, is deposited on the bone support. The hemostasis carried out previously will avoid the dilution of the material (3) sprayed and promote its adhesion to the bone support (13). Hemostasis produces a layer of blood clots (10) consisting of collagen and fibrosis in the form of a membrane 30 (10) adhering to the bone. The volume of the cleaning and hemostasis liquid (9) must be chosen so as not to dilute the said layer of blood clots. The volume of liquid (9) released during this first intervention can be between 2 and 250 ml, preferably between 10 and 80 ml. The layer of blood clots consisting of collagen and fibrosis acts as an adhesive vis-à-vis the grains of the pulverulent material (3) projected using the second instrument (2). The sprayed material (3) will then attach to the layer of blood clots (10) made up of collagen and fibrosis to form a film (14) covering it intimately. Thanks to the porosity and the roughness of the sprayed material (3) used, it will be

  then absorbed and integrated by adsorption of the liquid phase of collagen.

  When the surgical cement is injected, the film (14) thus formed at the level of the bone surface will

  reduce the risk of thermal necrosis resulting from the polymerization of surgical cement and its exothermic reaction.

A 2845591

  The method of use and its apparatus according to the invention allows the projection of a material (3) into a bone cavity or onto a sharpened bone surface and promotes the adhesion of this projected material (3).

on the bone support.

  The process and its apparatus (1 & 2) according to the invention will, thanks to the activation by the layer (10) of collagen on the film of pulverulent material (3) deposited on the bone support, reduce and compensate for the phenomenon of necrosis chemical or thermal bone resulting from the polymerization reaction during

  the injection of surgical cement thanks to the constitution of new bone directly affixed to the cement.

  Figure 1: Injection of the cleaning and hemostatic product.

  Figure 2 & 2a: Projection of the filling or treatment material using a gas

1 0 propellant.

  Figure 3: Projection of the filling or treatment material using a source

mechanical energy.

Claims (7)

  1 - Apparatus (1) (2) for projecting and adhering a material (3), in powder form, on the surface of a sharpened bone cavity (12) or on a bone cut (13), in particular to to promote the formation of bone tissue in contact with an implant or in contact with surgical bone cement used to fix an implant, characterized in that it comprises a projection instrument (2) comprising a propulsion means (6) and at least one device such as a cannula (5) penetrating into the bone cavity (12), or a sleeve (11) covering the bone cut (13) to be treated. One (5) or the other (11) device, containing the material (3) in powder form, is provided, on its portion in relation to the bone to be treated, with a network of orifices (4) in the form of holes or slits; These holes (4) are slightly larger than the gains in material to allow the material to be   evacuated with sufficient velocity to adhere to the layer of blood clots (10).   2 - Apparatus according to claim 1 characterized in that the means for propelling said material (3) in powder form is mechanical (7), for example by centrifugal spraying, or under form of a propellant gas (6).   3 - Apparatus according to claim 1 or 2 characterized in that the material (3) in powder form must have a particle size between 20 and 400 microns, preferably between 100 and microns.   4 - Apparatus according to one of claims 1 to 3 characterized in that said material (3) under   powder form consists of a bone substitute or a filling material.   5 - Apparatus according to one of claims 1 to 4 characterized in that said material (3) under   pulverulent form is a hydroxyapathite powder, preferably mainly crystalline, in order to compensate for the chemical or thermal toxicity of the cement by accelerated osteogenesis thanks to the action   physico-chemical of the projected material.   6 - Apparatus according to one of claims 1 to 5 characterized in that said material (3) under   powder form is associated with at least one product with a therapeutic or preventive objective.   7 - Apparatus according to one of the preceding claims characterized in that it comprises, in   in addition, a first instrument (1) consisting of a container playing the role of a bellows (for example in the form of a pear) ending in a nozzle whose length is variable and allowing the diffusion, in droplets or in small fine jets, a cleaning liquid (9) and promoting hemostasis, for example, hydrogen peroxide. The volume of the cleaning and hemostasis liquid (9) must be chosen, so as not to dilute the said layer (10) of blood clots, between 2 and 250 ml, preferably between 10 and 80 mi. The hemostasis thus produced avoids dilution of the sprayed material (3) and promotes its adhesion to the bone support.