ZA200601135B - Method for impregnating a porous bone substitute material - Google Patents

Description

=2008/07135

English translation of the specification of the International Patent Application No.

PCT/CH03/00537 “Method to impregnate a porous bone replacement material” in the name of Mathys Medizinaltechnik AG

Method to impregnate a porous bone replacement material 2018/PCT 8.8.2003

The invention concerns a method to impregnate a porous bone repla. cement material according to the preamble of patent claim 1 as well as a chamber to impregnate a porous bone replacement material according to the preamble of claim11® .

From WO 02/068010 Muschiler a device is known, in which a bone narrow extract is mechanically mixed with a porous bone replacement material. In this conjunction the bone marrow extract can be squeezed into or aspirated through the bone replacement material by means of two syringes, so that it will be flushed by the bone2 marrow extract.

Consequently, in the case of this known method the air situated in the bone replacement material will not be removed.

A further device to impregnate a porous, biocompatible bone replacem ent substance is known from US 6,049,026 Muschler. This known device comprisess a chamber to accommodate the bone replacement body as well as a first container above the chamber to store an impregnating agent and below the chamber a second container to accommodate the impregnating agent flowing through the chambe r with the bone replacement substance in it. By opening the first valve, arranged I>etween the first container and the chamber, the impregnating agent flows into the chamber with the bone replacement substance. As soon as the chamber is filled, & second valve, arranged between the chamber and the second container, is opered, so that the impregnating agent can flow to the second chamber through a diaphragm provided below the bone replacement substance. A disadvantage of this known device is that the capacity of the chamber cannot be modified, so that for bone replac.ement bodies of various sizes chambers of varying sizes are required.

In the case of the usually applied me thod, whereby such formed bodies from porous bone replacement materials are placed into a shell with the patient's own blood, thease known devices also have the disadwantages that during the impregnation it is not assured that + solid blood constituents, like for exams ple blood platelets or other cells would be able to advance up to the core of the implant. The blood cells will concentrate and held firamly at the edges of the implant (filtering effect of the bone replacement material), and * the entire air could be removed from the implant. Air inclusions form a barrier for the growing in of the bone and hinder the transformation of the resorbable bone replacement material.

This is where the invention wants to provide remedy. The object of the invention iss to produce a method to impregnate a porous bone replacement material that removes the air situated in the pores of the bone replacement material and replaces it with the desired impregnating agent.

This invention achieves this objective by a method to impregnate a porous bone replacement material having the featu res of claim 1, as well as by a chamber for the impregnation of a porous bone replacernent material having the features of claim 11.

Further advantageous configurationss of the invention are characterised in the dependent claims.

The advantages achieved by the invention are essentially that as a result of the method according to the invention the air, situated in the pores of the bone replacement material, can be removed and the desired impregnating agent can penetrate into #he pores.

In a preferred embodiment the air or gas is evacuated upwards through the opening provided in the chamber against the gwavity vector, so that the impregnating agent will be retained in the chamber by the gravi-ty.

The bone replacement material can be present in the form of a block, preferably in the form of a dice, cylinder, hollow cylinder, disc, wedge, cone, truncated cone or a sphere or in another execution of the method in the form of granules.

In yet another execution the impregnating agent comprises osteoindu ctive and/or osteogenic substances, in particular body cells, bone marrow or bone marrow components, blood or blood constituents or a combination thereof.

In a further execution, by means of the vacuum, produced in step d) of th e method in accordance with claim 1, the ambient pressure initially prevailing in the chamber is reduced from 1 bar to below 0.9 bar, preferably below 0.6 bar.

In yet another further execution of the method by means of the vacuum, produced in step d) of the method in accordance with claim 1, the ambient pressure initially prevailing in the chamber is reduced from 1 bar to below 0.2 bar, preferably below 0.1 bar.

The introduction of the impregnating agent can be carried out * by aspirating the impregnating agent through one of the two openings of t he chamber by the flow-through of the negative pressure, * by pressing in the impregnating agent through one of the two openings of t he chamber by the flow-through of the excess pressure, or * by multiple repeating of the steps d) and e) of the method in accordance wish claim 1.

In a preferred embodiment the internal capacity V of the chamber is variab le, whereby the chamber preferably comprises a cylindrical container with an internal thread and a matching lid with external thread, so that the internal capacity V of the chamber is variable by screwing the lid into the cylindrical container to a greater or le sser depth.

This will result in the advantage, that a single size chamber will be a dequate to accommodate implants of various sizes.

Because the chamber will be filled in this manner with a porous bone replacement material, the total capacity v of which is smaller than the internal volum e V of the chamber, th e bone replacement material can be partly or fully immersed in the impregnating agent.

In another exeacution of the chamber the bone replacement m. aterial is accommodated in an implant rmade from metal and/or plastic material in such a manner, that it communicates, at least partly, with the surface of the implant.

The invention and developments of the invention are explaimed in detail below, based on partly sche matic illustrations of a plurality of embodiments _

They show in:

Fig.1 - a perspective view of a chamber to carry out the method according to the invention, together with a syringe,

Fig.2 - an excploded view of a chamber to carry out the method according to the invention,

Fig.3 - a longi tudinal section through a chamber to carry ou t the method according to the invention,

Fig.4 - a top view on the chamber illustrated in Fig.3 to carry out the method according to the imvention.

Fig.1 shows a chamber 2 with a body, consisting of the bore replacement material 1 and enclosed in the hollow space. The chamber 2 has two Openings 3, 4, that can be connected airtight with a syringe 15. As impregnating age=nt 5 the syringe 15 may contain in its h ollow chamber osteoinductive and/or osteogeniic substances, in particular body cells, b one marrow and/or bone marrow components, blood and/or blood constituents. Together with the syringe 15, the chamber 2 i Hustrated here serves the purpose of carrying out the method according to the inventior, comprising the following steps:

> >

A» a syringe 15, filled with the impregnating agent 5, is preferably connected to the bottom opening 4 of the chamber 2. The top opening 3 remains open. Both operings 3, 4 are constructed as Luer-openings with a connecting piece 21, 25 each, josined with the chamber 2 and having tapered bores. The impregnating agent 5 is now injected by means of the piston 12 through the bottom opening 4 into the chambeer 2, so that the block of porous bone replacement material 1 is surrounded by the impregnating agent 5 and is immersed therein partially or completely;

B) the top opening 3 is now closed off:

C) following this the piston 12 of the syringe Sis withdrawn, so that a negative pres=ure or vacuum will occur in the chamber 2. By virtue of the vacuum the air existing irm the pores of the bone replacement material 4 expands, so that it exits from the pores into the surrounding impregnating agent 5. Since one deals here with a closed system, the impregnating agent 5 is aspirated only partly by the movement of the piston. This is also feasible only when air is still contained in the chamber 2. A large number of impregnating agents 5 may have adhesive properties, so that they adhere to the surface of the bone replacement material 1 and will not be aspirated by the movement of the piston;

D) in the next step the piston 12 of the syringe 5 is pressed in the original position , so that the vacuum in the chamber 2 will be terminated. The block of bone replacement material 1, surrounded by the impregnating agent 5 does not, of course, now absorb air in its pores but impregnating agent 5, so that an impregnation of the beone replacement material 1 takes place. The evacuation/cancellation of the vacuunn in the chamber 2, that can be carried out by means of the syringe 5, can be repeated several times to increase the degree of impregnation. By virtue of its adhesion =and the capillary effect of the structure of the porous bone replacement material 1 the impregnating agent 5 will be more likely be absorbed than air.

Another execution of the method is such, that after the first syringe 15, filled with the impregnating agent 5, is connected to one of the two openings 3, 4, a second, unfilled syringe 15 (not illustrated) is connected to the other opening 3, 4, and the hollow space of t he chamber 2 is evacuated by withdrawing the piston and simultaneously, due to the negative pressure produced, the impregnating means 5 is aspirated from the hollow space of the syringe 15 into the hollow space of the chamber 2. The air in the pores of the bone replacerment material 1 exits from the pores. Followinga this, by pushing in the piston of the secosnd syringe, air is moved again into the chambe-r 2, so that the vacuum is terminated aga in in the chamber 2 and the impregnating age nt 5 can penetrate into the pores of the bone replacement material. If necessary, the piston of one of the syringes can be withdrawn and the chamber 2 can be evacuateed again. The steps of evacuation and cancellation of the vacuum can be simply repea-ted in this manner until the pores in the bone replacement material 1 are adequately ventilated and filled with the impregnating rmaterial 5.

According to yet another execution of the method the second syminge (not illustrated) is used to increase the vacuum. Because this second syrin ge is not filled with impregnating agert 5, it can have a considerably greater capacity than the first syringe 13, filled with impr egnating agent 5. Figs.2-4 illustrate an embodiment of the chamber 2, that comprises a cylindrical container 6 coaxia_l with the central axis 10 and a coaxially fasten able lid 8. In its hollow space 13 the container 6 has an internal thread 7 that is coaxial with the central axis 10, so that the lid 8, having on its jacket surface an external thread 9 that matches the internal thread 7, can be detachably joined with the container 6. T he internal thread 7 in the container 6 extends over the entire length of the hollow space 13. The external thread 9 on the latceral jacket surface of the lid 8 extends over the entire axial length of the lid 8, so that thee lid 8 can be screwed also into the hollow spaace 13 of the container 6 and consequently the free capacity in the hollow space 13 of tlhe container 6 can be reduced until the fwont end 17 of the tubular extension 27 of the | id 8 abuts against the bottom 16 of the container 6. The internal thread 7, as well as the external thread 9, are executed as multi-sstart threads. The bottom 16 of the container 6 has a depression 20, where a connecting piece 21 with a central bore and concentric wiith the central axis 10, is provided. The ceantral bore 24 of the connecting piece 21 forms the opening 4. At its free end 22 the corinecting piece 21 is provided with two radially p rotruding cams 23, so that a standard syringe 15, having a construction matching the cornecting piece 21 and an internal thread -on its opening, can be screwed over the conn ecting piece 21 (Luer joint). Instead of the Luer-joint the central bores 24 of the connecting pieces 21, 25 can have a tapered shape in such a manner, that a syringe 15 with sstandard taper can be i 7 introduced into one of the central bores 24 of the connecting pieces 21, 25 armd fastened by means of the tapered connection.

The connections can be chosen alsso in such mariner, that various adapters can be joined in an airtight manner.

By virtue of arranging the connecting piece 21 in the depression 20 in such a manner, that the cconnecting piece 21 does not protrude past the bottom 16 of the container 6, the containesr 6 can be placed on its bottom without tipping.

Similarly to that on the outside of the coveer plate 18 of the lid 8 a second connecting piece 25 is provided, that is bore-d through concentrically with the central axis 10. The connecting pieces 21, 25 are ide=ntical.

To facil itate the screwing on or off the chamber 2, two axially protruding protrusions 11 are provided on the outside of the cover plate 1 8 of the lid 8 and axially extendin. g grooves

26 on the outer jacket surface of the container 6.

Claims (15)

rr tC Patent claim

1. A method to impregnate a porous bone replacement material with a liquid impregnating agent, characterised in the following steps: a) enclosing the bone replacement material in a chamber with two openings that can be closed, b) introducing the impregnating agent into the chamber until the bone replacement material is at least partially immersed in the impregnating agent, c) closing one of the two openings, d) evacuating the chamber at least partially via the other, open, opening so that the air contained in the pores of the bone replacement material is at least partially removed from it, and e) supplying air or gas through one of the openings to terminate the vacwuum produced in the chamber so that the vacuum produced in the pores of the bone replacement material is terminated by the impregnating agent penetrating into the pores of the bone replacement material immersed into the impregnating agent.

2. A method according to claim 1, characterised in that in the step d) the air or the gas is evacuated through the opening provided on the top of the chamber against the gravity vector.

3. A method according to claim 1 or 2, characterised in that the bone replacerment material is present in the form of a block, a dice, cylinder, hollow cylinder, disc, wedge, cone, truncated cone or a sphere.

4. A method according to claim 1 or 2, characterised in that the bone replacerment material is present in the form of granules.

5. A method according to any one of claims 1 to 4, characterised in that the impregnating agent comprises osteoinductive and/or osteogenic substances. AMENDED SHEET

. -

6. A method according to any o ne of claims 1 to 5, characterised in that the vacumum, produced in step d), reduce s the pressure initially prevailing in the chamber f"rom 1 bar to below 0.9 bar.

7. A method according to claim 6, characterised in that the vacuum, produced ir step d), reduces the pressure initially prevailing in the chamber from 1 bar to belo®w 0.2 bar.

8. A method according to any one of claims 1 to 7, characterised in that the impregnating agent is introcluced into the chamber by aspiration through one= of the two openings by the flow-th rough of the negative pressure.

9. A method according to any one of claims 1 to 7, characterised in that the impregnating agent is introduced into the chamber by pressing it through ones of the two openings by the flow-th rough of the excess pressure.

10. A method according to any one of claims 1 to 7, characterised in that steps cd) and e) of the method are repea_ted several times.

11. A chamber to impregnate &a porous bone replacement material with an impreegnating agent, wherein the chamber has two openings that can be closed and has a variable internal capacity W, characterised in that it comprises a cylindrical czontainer with a hollow space , an internal thread provided in the hollow space and a matching lid with external thread and that the internal capacity V of the cha mber is variable by screwing the lid into the cylindrical container to a greater or les ser depth.

12. A chamber according to claim 11, characterised in that the chamber contai ns a porous bone replacement material , the total capacity v of which is smaller than the internal volume of the charmber .

13. A chamber according to cl aim 12, characterised in that the bone replaceme=nt material is present in the form of a block, a dice, cylinder, hollow cylinder, disc, wedge, cone, truncated cone or a sphere. AMENDED SHEET

. = 10

14. A chamber according to claim 12 or 13, characterised in that the bone replacement material is accommodated in an implant made from ranetal and/or plastic material in such a man ner, that it communicates, at least partly, with the surface of the implant.

15. A chamber t o impregnate a porous bone replacement material with an impregnating agent subst antially as herein described and as illustrated in Figures 2 to 4. AMENDED SHEET

Abstract

A method to impregnate a porous bone replacement materi al (1) with a liquid impregnating agent (5), wherein a) the bone replacement material (1) is or will be enclosed in a cchamber (2) with two openings (3, 4) that can be closed,

b) the impregnating agent (5) is introduced into the chambes (2) until the bone replacement material (1) is at least partly immersed in the impregnating agent (5),

c) one of the two openings (3, 4) will be closed,

d) the chamber (2) is evacuated at least partly via the other, ope n, opening (4, 3), so that the air contained in the pores of the bone replacement mmaterial (1) is at least partly removed from it, and e) the vacuum produced in the chamber is terminated again by swpplying air or a gas through one of the openings (3, 4), and f) the vacuum produced in the pores of the bone replacement material (1) is terminated by the impregnating agent (5) penetrating into the pores of thme bone replacement ma terial (1) immersed into the impregnating agent (5).