WO2023280452A1

WO2023280452A1 - Method for producing an augmenting active agent which has a composite material for replacing or forming lost bone substance

Info

Publication number: WO2023280452A1
Application number: PCT/EP2022/059856
Authority: WO
Inventors: Oliver Zernial
Original assignee: I Love Implants Gmbh
Priority date: 2021-07-07
Filing date: 2022-04-13
Publication date: 2023-01-12
Also published as: DE102021117517B3; EP4366793A1

Abstract

The invention relates to a method for producing an augmenting active agent which has a composite material for reconstructing or regenerating an at least partly lost bone substance, for filling up bone defects, and/or for optimizing a bone implant site. The invention also relates to a correspondingly produced augmenting active agent (1).

Description

METHOD OF FABRICATION OF A COMPOSITE AUGMENT TO REPLACE OR REBUILD LOST BONE SUBSTANCE

The invention relates to a method for producing an augmentation comprising a composite material for the reconstruction or regeneration of at least partially lost bone substance, for filling bone defects and/or for optimizing a bony implant site. The invention also relates to a correspondingly produced augmentation.

In the method described, sodium citrate is first added to a sample of autologous peripheral venous blood taken from the patient in order to stop blood clotting. In a further step, centrifugation first separates hematocrit with red blood cells, buffy coat with white blood cells and blood plasma, and then the blood plasma is separated into a first light, fibrin-rich blood plasma fraction and a second, heavy, thrombocyte-rich blood plasma fraction.

The use of autologous blood plasma is an established method in medicine, for which purpose peripheral venous blood is first taken from the patient and the liquid plasmatic part is separated from the cellular part of the blood. In this way, platelet-rich blood plasma, so-called PRP (platelet rich plasma), is obtained, which contains a comparatively high concentration of thrombocytes and growth factors. Due to the coagulation and growth factors contained in blood plasma, such as PDGF, VEGF and TGF-Beta 1, the use of appropriate blood plasma preparations can accelerate physiological healing processes and promote vascular and tissue regeneration. Due to these healing-promoting properties, blood plasma preparations have gained in importance in recent years, especially in regenerative dentistry and implantology.

Various methods are available for obtaining platelet-rich blood plasma (PRP). The invention described below is based on the classic process of Dr. Eduardo Anitua, as described for example in "Anitua, E.: A new approach to bone regeneration -PlasmaRich in Growth Factors-, Puesta al Dia Publicaciones, SL, Vitoria Spain, 277 pp (2001)". . According to the method of Dr. Anitua (PRGF Platelet Rieh in Growth Factors) are separated from the rest of the blood, the red blood cells (hematocrit), after anticoagulation with sodium citrate and after simple centrifugation and plasma and platelets.

The resulting plasma can be divided into three layers. An upper light layer rich in fibrin, a heavier layer rich in thrombocytes and the buffy coat, which mainly contains leukocytes and is the heaviest layer overlying the hematocrit. The upper layer rich in fibrin (fraction"!) and the heavy layer rich in thrombocytes (fraction 2) are now pipetted off separately.

The coagulation function can be reactivated by the targeted addition of calcium and the plasma can be used in a targeted manner for a wide variety of applications.

Furthermore, a method for obtaining platelet-rich fibrin (platelet rich fibrin (PRF)) is known, which was first used in 2001 by Dr. Joseph Choukroun in “Choukroun J, Adda F, Schoeffler C, Vervelle A. Une opportunite en paro-implantologie: Le PRF. implant dentistry. 2001;42:55-62. Compared to other blood concentrates such as platelet-rich plasma and platelet-rich plasma enriched with growth factors (PRGF), the production of platelet-rich fibrin (PRF) does not require anticoagulants. The platelet-rich fibrin (PRF) production protocol, described in 2001, which uses glass blood collection tubes and a relatively high centrifugal force, produces a solid fibrin matrix, whereby the centrifugation separates the erythrocytes, the red blood cells, from the fibrin matrix to be separated. Because this fibrin matrix has been shown to contain leukocytes and platelets, it is also called leukocyte and platelet rich fibrin (L-PRF).

In the meantime, further studies such as “A. Kubesch et al., “Pre-clinical in vivo evaluation of Platelet-rich fibrin (PRF) scaffolds: G-force reduction in advanced platelet-rich fibrin (A-PRF) scaffolds increases scaffold integration and vascularization: First pre-clinical in vivo evaluation,” p. acta biomaterialia” proves that thrombocytes and leukocytes in the L-PRF tend to accumulate at the interface between the fibrin matrix and the red phase, whereas the fibrin matrix itself is almost cell-free. Among other things, “S. Ghanaati et al., "Advanced Platelet-Rich Fi brin: A New Concept for Cell-Based Tissue Engineering by Means of Inflammatory Cells," J. Oral Implantol., vol. 40, no. 6, pp. 679-689, 2014” and “K. El Bagdadi et al., “Reduction of relative centrifugal forces increases growth factor release within solid platelet-rich-fibrin (PRF)-based matrices: a proof of concept of LSCC (low speed centrifugation concept),” Eur. J. Trauma Emerg. Surg., Mar. 2017" that the reduction of the applied centrifugal force in the preparation of the solid PRF results in an enrichment of the fibrin matrix with leukocytes and thrombocytes. In this way, by suitably reducing the centrifugal force, it was possible to develop more leukocyte-rich forms of platelet-rich fibrin (advanced platelet rieh fibrin (A-PRF) and advanced platelet rieh fibrin plus (A-PRF+)).

It is at least partly a problem with the known methods that the extraction of the individual layers separated by at least one centrifugation takes place by means of a pipetting process, which requires manual handling steps, so that the quality can vary. In particular, this can lead to inconsistent plate counts, which are a potential source of error. Furthermore, depending on the method selected in each case, a plurality of process steps are required, so that the time required for the production of the composite materials required, for example for the treatment of a jawbone, is considerable. This in turn leads to sometimes considerable treatment or operation times.

Based on the methods known from the prior art and the problems described above, it would generally be desirable to standardize the production processes, reduce possible sources of error and provide a preparation that is equally suitable for as many clinical applications as possible. In this context, the invention is based on the object of specifying a method for producing composite materials, from which in turn augments to replace lost bone material can be produced, which can be implemented quickly and reproducibly with relatively simple means.

In particular, the blood coagulation should be able to be changed in a targeted manner while the method is being carried out, so that the blood coagulation can be controlled. The natural process of blood coagulation should be used here in order to produce targeted tissue and augmentations, in particular for bone regeneration. The method to be specified for the production of a composite material as a replacement for human bone material should therefore be based on natural processes and thereby enable comparatively rapid bone formation and stable bone structures to be produced. Above all, it should be achieved that biologically potent and sufficiently stable augmentates, which also have a high efficiency and breaking strength after their implantation in the human or animal body, can be produced from a composite material produced according to the method. The object described above is achieved with a method according to claim 1.

Claims 19 and 20 also specify bone replacement pieces that solve the problem on which the invention is based. Special developments of the invention are the subject matter of the dependent claims and are explained in more detail in the following description with partial reference to figures.

The invention relates to a method for producing an augmentation comprising a composite material for the reconstruction and/or regeneration of at least partially lost bone substance, for filling bone defects and/or for optimizing a patient's bony implant bed. The method first has the steps

Mixing a sample of autologous, peripheral venous blood taken from the patient and adding sodium citrate to stop blood clotting, producing blood plasma by centrifugation and at least partially separating erythrocytes, i.e. red blood cells, and leukocytes, i.e. white blood cells,

- Separating the blood plasma into a first light fibrin-rich and at least one second platelet-rich plasma fraction and adding a substance containing calcium, in particular calcium chloride, to the first light, fibrin-rich blood plasma fraction.

According to the invention, the method is characterized by the steps of separate provision of autologous bone material and allogeneic, xenogeneic, porcine, bovine and/or synthetic bone replacement material in a vessel,

Producing and activating a mixture by adding a substance containing calcium, in particular calcium chloride, to the second plasma fraction, impregnating the bone replacement material with the mixture and producing a mixture by mixing the mixture with the autologous bone material and forming the augmentate from the mixture.

In connection with the description of the invention, activation is understood to mean that at least one coagulation process or coagulation mechanism is set in motion. According to the method according to the invention, calcium chloride is added to both the first light, fibrin-rich blood plasma fraction and the second heavy, platelet-rich blood plasma fraction in correspondingly provided method steps for at least partial activation or initiation of coagulation, with the first blood plasma fraction preferably immediately before the planned use of the composite material calcium chloride is added. The second blood plasma fraction is preferably mixed with the allogeneic, xenogeneic and/or synthetic bone replacement material immediately after the addition of calcium chloride and the activation caused thereby.

With the aid of the method according to the invention, the coagulation of the blood plasma is first stopped and the blood plasma is separated into two fractions, namely a first light blood plasma fraction rich in fibrin and a second heavy blood plasma fraction rich in thrombocytes. Due to the coagulation of the blood plasma, further processing of the separated plasma fraction can take place at a later point in time and does not have to follow immediately after the blood sample has been taken. Preference as in close proximity, especially immediately before a medical treatment or an operation for which the composite material to be produced and an augmentation made from it is required, the first light, fibrin-rich blood plasma fraction is activated with calcium, the calcium being part of an added substance can. Calcium chloride is particularly preferably used.

After the addition of calcium, a fibrin matrix or a fibrin clot usually develops within 20-30 minutes, which is suitable for further processing, in particular for targeted shaping. It is therefore conceivable according to a preferred embodiment that this fibrin matrix or this fibrin clot is shaped as required, for example pressed into a type of membrane.

Furthermore, the invention provides that the second heavy, thrombocyte-rich blood plasma fraction is also activated with calcium, in particular a substance that contains calcium, such as calcium chloride. After, before or during the addition of calcium, the allogeneic, xenogeneic and/or synthetic bone replacement material is soaked with the activated mixture containing the second blood plasma fraction and calcium. If xenogeneic bone substitute material is used, porcine or bovine bone substitute material is preferably used. The bone substitute material is preferably impregnated with the activated mixture even before the allogeneic, xenogeneic and/or bone substitute material is brought into contact with the patient's autologous bone material.

According to a particular embodiment, an allogeneic, xenogeneic, such as porcine or bovine, and/or a synthetic bone substitute material is used here that has a grain size between 0.25 and 1 mm, so that the individual components have a maximum expansion in one direction of 0. 25 to 1 mm. Furthermore, with the method according to the invention, a mixture is produced by mixing the bone replacement material soaked with the mixture with the autologous bone material of the patient that is also provided and shaping the augmentation from the composite material produced.

In this context, it is pointed out that it can be advantageous to initially shape a preform of an augmentation that can later be adapted to the required shape as required and preferably also allows shaping during a treatment or operation. The essential feature of the method according to the invention is that autologous bone material removed from the patient is mixed with the bone replacement material soaked with the mixture.

It has been recognized as essential for the invention that the use of autologous bone material, which can be obtained from the patient with the help of a bone scraper, for example, maximizes the coagulation ability of platelet-rich blood plasma, in particular of a light, fibrin-rich and/or a heavy, thrombocyte-rich blood plasma blood plasma fraction is reached. Blood coagulation is usually based on three different functional mechanisms, with all three functional mechanisms of blood coagulation being activated when the method according to the invention is used. The method according to the invention is therefore based on the fact that due to the activation of the three different functional mechanisms of blood coagulation, the blood plasma produced and used, in particular a light blood plasma fraction rich in fibrin and a heavy blood plasma fraction rich in thrombocytes, can be used as an adhesive for the construction of composite materials .

According to the invention, cellular thrombocytic coagulation is activated by contact with tissue material which carries a von Willebrand receptor (GP Ib). If a thrombocyte comes into contact with an injured area of tissue, a transformation of the cell takes place immediately, so that the thrombocytes literally hook into one another. In addition, messenger substances are released that activate further coagulation cascades. If, as provided according to the invention, this is stabilized with blood plasma during the production of a composite material or an augmentation produced therefrom and the body's own tissue is added in the process, the full potential of coagulation is used. This significant advantage arises primarily from the fact that the collagen structure contained in the added autologous bone material and the blood vessel cells of the bone scraped from the donor area are used. Furthermore, when implementing the method according to the invention, maximum and rapid stabilization of a particulate augmentate is also achieved by activating the extrinsic plasmatic coagulation. In this functional mechanism, the so-called tissue factor or collagen triggers coagulation of the blood plasma. In this case, too, the use of tissue or wound material is of particular importance.

The third coagulation mechanism is intrinsic plasmatic coagulation, which can be activated, for example, by negatively charged surfaces. This coagulation mechanism is used almost exclusively in the methods currently used to obtain platelet-rich blood plasma products, so that the maximum possible coagulation potential is regularly not exhausted with these methods. According to the invention, this disadvantage is countered precisely by the fact that autologous bone material is also used to produce a composite material, and a comparatively strong stabilization effect is thus achieved just 1 to 5 minutes after the autologous bone material and the bone replacement material have been previously treated with the activated second heavy, thrombocyte-rich plasma fraction was mixed, a mixture was produced, ceases. In contrast to this, the methods known from the prior art are comparatively complex and require more time.

By using the method according to the invention for producing a composite material for an augmentation, wound and/or bone healing is accelerated and all coagulation mechanisms or coagulation cascades are used to increase adhesive forces in the production of tissue and bone composites to reach. With the help of composite materials and augments produced in this way, a surgeon is given new options in the treatment of bone defects. In particular, it is possible to produce almost any amount of tissue and/or bone material, which on the one hand can be flexibly adapted to the respective treatment situation and on the other hand is largely obtained from the body's own substances and is therefore biologically very potent. Furthermore, operation and treatment times can be significantly reduced and the risk of infection minimized. Furthermore, the reduction in removal morbidity leads to a reduction in the complication rate.

The composite material and/or augmentation produced according to the invention can be used in a particularly suitable manner, at least in part, for relining the soft tissue of a patient, which in turn achieves improved and faster wound healing and once again minimizes the risk of wound dehiscence. These advantages are important for the practitioner, but above all for the patient.

According to a special development of the invention, it is provided that an antibiotic, in particular clindamycin or doxycycline, is optionally added to the autologous bone material provided in the vessel. The addition of an antibiotic according to the body dosage serves the local antibiosis and also the inhibition of collagenases, which release bacteria in an infection for tissue penetration. The addition of a drug to the plasma depends on the legal circumstances according to Section 65 of the Drugs Act and has not yet been finally clarified.

In a further embodiment of the method according to the invention, the mixture is made in such a way that it has a proportion of 25 to 50% by volume of autologous bone material. According to a very special development of the invention, a mixture is produced which has a proportion of 50% by volume of the autologous bone material and a proportion of 50% by volume of the bone replacement material impregnated with the mixture. In this case, the mixture in turn contains at least part of the second heavy blood plasma fraction rich in thrombocytes and calcium, preferably calcium chloride, which is used to activate the coagulation of the second blood plasma fraction. Particles, preferably bone chips, of a particular bone of the patient that is as vital as possible are preferably used as the autologous bone material. Such bone particles are advantageously obtained with a disposable bone scraper from the bone region to be treated, for example in the area of a jawbone, or a separate bone access.

According to a preferred embodiment of the invention, the sample of autologous peripheral venous blood mixed with sodium citrate is centrifuged horizontally at a rotary speed of 1200-2400 rpm, preferably about 1900 rpm.

According to an alternative embodiment, it is also provided that the coagulation is activated and the bone substitute material is 100% biologized by still liquid plasma of a mixture consisting, for example, of 50% autologous bone material and 50% bone substitute material with a 100% bone substitute material is admitted. Here, the supernatant liquid is used to activate the 100% bone replacement material. Bone replacement material made from porcine or bovine bone is preferably provided as the bone replacement material. Porcine bone replacement material, ie xenogeneic bone replacement material from pigs, is particularly preferably used, especially for the production of an augmentation that is not critical in terms of volume and is characterized by comparatively rapid bone healing. In the case of volume-critical defects, on the other hand, bovine bone replacement material, i.e. xenogeneic bone replacement material from cattle, is preferably used.

Bone substitute material is preferably used that does not need to be heated very much; in particular, high-temperature bone substitute materials are dispensed with, since these are not suitable for use in the method according to the invention due to their comparatively great hardness. Irrespective of the type of bone replacement material used, however, it is essential for the invention that the autologous bone material and the allogeneic, xenogeneic and/or synthetic bone replacement material are initially provided separately from one another. A mixture containing these two materials is only produced after the allogeneic, xenogeneic and/or synthetic bone replacement material has been soaked with a mixture which contains at least part of the second heavy, thrombocyte-rich blood plasma fraction, which contains calcium, in particular calcium chloride, has been activated.

A further embodiment according to the invention provides that the allogeneic, xenogenic and/or synthetic bone replacement material with the mixture contained therein of at least part of the second heavy, thrombocyte-rich blood plasma fraction and calcium chloride is mixed with the autologous bone material for more than 30 seconds to produce a mixture is mixed. Advantageously, the period of time for the mixing is limited to a maximum of 30 seconds, since otherwise there is a risk that the polymerisation or concatenation of the fibrin will be destroyed. Preferably, following the production of the mixture, which has autologous bone material and allogeneic, xenogeneic and/or synthetic bone replacement material with calcium chloride-activated second, platelet-rich blood plasma fraction, the mixture is shaped, in particular manually using suitable instruments and/or carried out using a negative mould. A corresponding needs-based shaping or modeling is preferably carried out over a period of 30 to 60 s. With regard to possible processing or further use of the mixture and/or an augmentation at least pre-shaped from it, it must be taken into account that around 120 to 240 s after the start of the Mixing of the autologous bone material with the bone replacement material, the coagulation processes have progressed so far that the mixture or the augmentate is so stable that it can be grasped with tweezers and generally processed further.

According to a further special embodiment, the stability is additionally increased by at least partially immersing the augmentation material, which cannot yet be grasped with tweezers, in liquid plasma, preferably in the platelet-rich second blood plasma fraction for 10 to 20 s, in particular for 15 s. In this way, thrombocytes can cross-link one another with liquid fibrinogen monomers via a special receptor (GP IIb/IIIa), whereby the actual plasmatic coagulation is not required for this. This process is thus used in a preferred manner in order to achieve additional stabilization of the augmentation.

According to a further special embodiment of the invention, it is conceivable in this context that a shaped augmentation is processed further, for example by being cut and/or rolled, in order to produce the shape required in each case by the patient. Alternatively or in addition, it is conceivable that the augmentation is compacted in such a way that the granulation is reduced, which on the one hand facilitates reshaping, in particular with regard to the production of a bone regenerate, but on the other hand reduces the volume of the augmentation.

A further development of the invention further provides that the augmentate is at least temporarily brought into contact with at least part of the first light, fibrin-rich blood plasma fraction, in particular is at least temporarily immersed in the first blood plasma fraction. This accelerates the fibrin crosslinking in the first, light, fibrin-rich blood plasma fraction and improves the quality of the fibrin crosslinking. Preferably, the augmentate is contacted and/or immersed in the first light, fibrin-rich blood plasma fraction for a few seconds. The prerequisite for this is that the first light, fibrin-rich blood plasma fraction has not yet coagulated at this point in time.

Following this bringing into contact, the first light, fibrin-rich blood plasma fraction is completely dabbed through to form a cake-like structure within about 3 to 10 minutes, thus forming a matrix that is correspondingly solid compared to the initial state. There is therefore no need for additional warming or the addition of medication to accelerate coagulation.

According to an advantageous further development, this cake-like structure is pressed into a membrane, whereby the concentration of the fibrin with the contained therein Growth factors are further increased and unnecessary fluid is removed from the fibrin.

In a special embodiment, a flat membrane is produced here, the diameter of which can generally be specifically determined, which, however, usually depends on the amount of platelet-rich blood plasma obtained and the bottom diameter of the vessel, for example a small glass bowl in which the first light, fibrin-rich blood plasma fraction is stored. depends. According to a special development, a thickness of the flat membrane is set in a suitable manner by applying and/or varying a pressure and/or a pressing time. A membrane is advantageously produced in the form of a 1 to 2 mm thick disc-shaped element, also referred to as a crepe. Such a disc-shaped element is preferably suitable for use as an additional adhesive element or for soft tissue relining.

According to a further embodiment of the invention, it is conceivable in this connection to fold and press the previously described disc-shaped element and use it in its shape, adapted as required, as a tissue block for soft tissue lining or for filling soft tissue defects. In this way, for example, so-called punches can be produced in an advantageous manner, which are suitable, for example, for sealing alveoli in the immediate implantation of dental implants or for filling fresh tooth extraction alveoli.

By bringing the augmentate into contact at least temporarily with the first light, fibrin-rich blood plasma fraction, correspondingly modified augmentates can also be used in a particularly preferred manner as an insert in the area of a bone defect. It is therefore conceivable to use an augmentation modified in this way as a bone insert and/or for a bone reconstruction. It is advantageous here if the so-called bone bed is roughened before the insertion of an augmentation in the area of a bone defect, in particular freshened up with a bone scraper, so that at least a slight flow of blood occurs in this area. In this way, a fresh wound is produced to which an augmentation material produced according to the invention adheres in an advantageous manner, in particular rests firmly and thus remains in a stable position in the inserted position. Due to the properties of an augmentate produced according to the invention, further technical stabilization measures such as titanium grids, discs, membrane pins and/or reinforced membranes can be dispensed with in most cases. Advantageously, for the reconstruction of a bone defect, a combination of an augmentate produced according to the invention, which is covered with an absorbable collagen membrane, is also provided. Preferably, a porcine pericardial membrane is used for the covering. In a special further development it is provided that the resorbable collagen membrane is additionally soaked with platelet-rich blood plasma, in particular with at least part of the first light, fibrin-rich blood plasma fraction. As a result, the collagen membrane is modified in such a way that it fits snugly against an augmentate produced according to the invention and can preferably be used to cover it at least in certain areas. In this case, too, a collagen membrane modified in this way can be applied to an augmentation without further stabilization, pinning with an absorbable or non-absorbable membrane or other stabilization, such as the bone shells, being necessary.

Nevertheless, an absorbable collagen membrane is still necessary to create a barrier between the soft tissue introduced into the treatment area and the bone of the patient after the augmentation has taken place. This ensures that the healing process, in particular the growth of fibroblasts and blood vessels, starts from the bone bed and not from the soft tissue. In this way, the principle of guided bone regeneration (GBR - Guided Bone Regeneration) is used particularly effectively.

According to a further embodiment, the augmentate covered with the collagen membrane is also covered with a disk-shaped element formed from at least part of the first light, fibrin-rich blood plasma fraction, which is also referred to as a crepe. Such a covering is preferably produced by sliding the disk-shaped element over the collagen membrane, so that the augmentation covered with the collagen membrane is covered over the entire surface by the disk-shaped element. It is important to ensure that the coagulation process has progressed sufficiently in the disk-shaped element and that a sufficient amount of liquid has been squeezed out.

During the treatment of a bone defect, the combination made of augmentate, collagen membrane and disc-shaped element is advantageously pressed onto the bone bed in the treatment area with slight pressure, thereby achieving additional bonding of the individual components.

An augmentation made according to the invention from a composite material, which was implanted in a patient to replace a bone defect, is the rule loadable after 4 to 6 months, so that dental implants can be used, for example. If a composite material with a comparatively high proportion of allogeneic, xenogeneic and/or synthetic bone substitute material is used, this time can be extended to 6 to 9 months. If it is not possible to produce sufficient bone material in a first step, a further corrective structure can be efficiently built up during the implantation according to the same principle.

An augmentate produced according to the invention is preferably suitable for use in the following treatments:

Soket Preservation: For filling an intact alveole Ridge Preservation: In the case of bone defects or defects in the walls of an immediate implantation for filling and additional reconstruction of bone defects: For filling empty bone spaces, with additional attachment or superimposition if necessary

Contour augmentation: If a jawbone is too narrow for an implant, horizontal and/or vertical attachment and placement can take place

Horizontal attachment plastic with two-stage implantation

Vertical bearing plastic with two-stage implantation external sinus lift: vertical bone augmentation in the upper jaw by elevating the maxillary sinus floor with bony lateral access internal sinsulift: vertical bone augmentation in the upper jaw by elevating the maxillary sinus floor through the implant drilling from above

Interpositionplasty: Spreading a bone and inserting an augmentation in the opened space

Combination with iliac crest or other bone augmentation, such as autogenous or autogenous bone shells.

Treatment of bone defects outside the mouth and jaw area

The invention is explained in more detail below using exemplary embodiments without restricting the general inventive idea and with reference to a figure. The figure shows:

Fig. 1: Flow chart of a method for producing a material having a composite material and augmentation Fig. 2: Schematic representation of the individual process steps for the production of an augmentation designed according to the invention.

FIG. 1 shows a flow chart of a method for producing an augmentation having a composite material for the reconstruction and regeneration of at least partially lost bone substance, for filling bone defects and/or for optimizing a bony implant bed of a patient. To produce a corresponding augmentation, a sample of autologous peripheral venous blood is first taken from a patient. In this case, 4 to 8 blood collection tubes, each with a volume of 9 ml, are filled with the sample taken according to the exemplary embodiment described. The blood collection tube contains sodium citrate, which permanently stops the blood from clotting.

In a next step, the blood sample taken is centrifuged horizontally at a rotational speed of 1900 rpm for a period of 8 minutes. Due to the centrifugation carried out, blood serum and blood plasma are separated and two blood plasma fractions are formed, namely a first light, fibrin-rich fraction and a second heavy platelet-rich blood plasma fraction. The two different blood plasma fractions are obtained by specifically pipetting off the blood serum. Any cells, mostly erythrocytes (hematocrit) and the buffy coat (leukocytes) are discarded and not used for further processing.

In a next step, the first light, fibrin-rich blood plasma fraction is activated with calcium chloride, which is added to the first light, fibrin-rich blood plasma fraction in a dosage with an effectiveness of 2 IU/ml in a glass bowl. The process steps mentioned above correspond to the protocol for the production of platelet-rich plasma (PRGF) according to Dr. anitua. This is followed by process steps according to the invention.

First, the first light, fibrin-rich blood plasma fraction within the preoperative sterile setup is activated with calcium chloride, so that coagulation processes begin within this blood plasma fraction. The temperature control provided by Anitua is not necessary or superfluous because, if necessary, the coagulation can be accelerated at a later point in time by dipping the augmentate then produced into the first blood plasma fraction and thereby activating the platelet coagulation within a few minutes . Furthermore, the patient's autologous bone material is provided, which was obtained by an operator using a disposable bone scraper from the defective bone area or from another bone of the patient. Care is taken to ensure that particulate bone material that is as vital as possible is provided. Compared to other techniques for harvesting autologous bone material, purely cortical superficial scraping is less invasive or morbid, does not create defects and usually does not open the medullary canal. Anatomically critical structures are spared, and the risk of complications of this type is significantly reduced. The bone chips obtained in this way are placed in a metal bowl together with an allogeneic, xenogeneic and/or synthetic bone substitute material, care being taken to ensure that the autologous bone material and the bone substitute material are not yet brought into contact with one another at this point in time. In particular, the chip-shaped autologous bone material is not yet mixed with the bone replacement material that is used.

The bone replacement material is selected in such a way that it has a grain size of between 0.25 and 1 mm, so that the individual particles have a maximum extent of 0.25 to 1 mm in a direction. Furthermore, the type of bone replacement material is selected depending on the bone defect to be treated. While porcine bone replacement material is used for a volume-critical augmentation that is used in particular to treat multi-walled bone defects, but which should heal quickly, usually within 4 to 5 months, into the defective bone, volume-critical bone defects with few bone walls are used for the treatment and/or taking slow healing processes into account, which take 6 to 9 months, bovine bone replacement material is preferably used. High-temperature bone replacement materials are usually not used due to their extreme hardness and the limited possibility of satisfactory remodeling.

In a further step, the second, thrombocyte-rich blood plasma fraction is activated with calcium chloride in a dosage with an effectiveness of 2 IU/ml and the bone replacement material provided is finally soaked with this activated mixture, which contains at least part of the second, thrombocyte-rich blood plasma fraction and calcium chloride . As a preventive measure, a drop of clindamycin in a ratio of about 600 mg per 80 kg body weight is optionally added to the autologous bone material that is also provided. This is used for local antibiosis and in addition inhibition of collagenases secreted for tissue penetration by infectious bacteria.

Following the previous steps, the bone replacement material soaked with the mixture of second, thrombocyte-rich blood plasma fraction, activated by calcium chloride, is mixed with the autologous bone material in a ratio of 50:50 vol% for a maximum of 30 s to form a mixture, from which the required augmentation is malleable. If the proportion of bone replacement material is increased, the volume of the augmentation becomes comparatively more stable, and augmentations with a larger volume can thus be produced. If, on the other hand, the proportion of autologous bone material in the mixture is increased, bone that has been built through can be produced more quickly, but with the risk of resorption and the associated reduction in the volume of the augmentation material.

The mixing process is stopped after 30 seconds at the latest, otherwise the polymerization or concatenation of the fibrin will be destroyed. From this point in time, the augmentation is modeled manually and, if necessary, with the aid of a negative mold and/or a system for the additive production of a shaped body in a suitable manner for a further 30 to 60 s as required. Approximately 120 to 240 s after the beginning of the mixing process, coagulation has progressed to such an extent that the augmentate formed from the mixture can be grasped with tweezers and processed further in almost any way.

In order to further increase stability, the augmentation material, which is often not yet properly graspable with tweezers, is immersed in plasma that is still liquid, preferably in the second blood plasma fraction rich in thrombocytes, for about 15 s. Here, the thrombocytes can cross-link one another with fibrinogen monomers via a special receptor, in particular glycoprotein IIb/IIIa, so that plasmatic coagulation is not required for this. This process is thus used in a targeted manner in order to achieve additional stabilization of the augmentation.

For example, it is possible to cut or roll this. Optionally, the augmentation material can be further compacted, thereby reducing the granulation in particular. This favors the remodeling of an augment or bone regenerate, but reduces its volume.

Furthermore, in order to accelerate the fibrin crosslinking in the first light, fibrin-rich blood plasma fraction and to optimize the quality of the fibrin crosslinking, the Augmentate immersed in the first blood plasma fraction for a few seconds. The prerequisite for this is that the first light, fibrin-rich blood plasma fraction has not yet coagulated. Alternatively, some excess liquid from the augmentation can be used. The first fibrin-rich blood plasma fraction will now form a matrix within 3 to 10 minutes and solidify or clod through to form a cake-like element. This cake-like element is then pressed into a membrane, increasing the fibrin concentration and removing unnecessary fluid from the fibrin. A flat membrane is usually formed in the form of a disk-like element whose diameter depends on the diameter of the bottom of the glass dish in which the first fibrin-rich blood plasma fraction is stored and on the amount of platelet-rich blood plasma obtained. Furthermore, the thickness of the disc-shaped element is adjusted by suitable adjustment and/or variation of the pressure exerted on the element and the duration of the pressing process. According to the embodiment described here, a 1 to 2 mm thick disc-shaped element, a so-called crepe, is produced, which element can be used as an additional adhesive element and/or for soft tissue lining.

It is possible to fold and/or press the disc-shaped element once or several times as required, in order to produce tissue blocks for relining soft tissue or for filling soft tissue defects. In this way, it is even possible to produce so-called punches to close alveoli when dental implants are placed immediately.

The augmentation that has now been produced can be inserted directly into the bone defect or used for the corresponding reconstruction to produce a bone reconstruction. The bone bed is freshened up with a bone scraper so that it bleeds easily. This creates a new wound to which the augmentation that is finally inserted adheres or sticks so that the augmentation remains stable in its position without the need for further technical stabilization measures such as titanium grids, bone discs, membrane pins or membranes.

The augmentation is then covered with an absorbable collagen membrane. According to the exemplary embodiment described here, a porcine pericardium membrane is used as the collagen membrane, which is preferably additionally impregnated with platelet-rich blood plasma, in particular with the second platelet-rich blood plasma fraction, and is bonded thereto. This offers the advantage that the membrane lies particularly smoothly on the augmentation. Also in this case no further stabilization measures or pinning of the membrane to the augmentation are necessary. With the help of the collagen membranes, a barrier can be created between the soft tissue and the bone, so that it is ensured that the healing, i.e. the ingrowth of fibroblasts and blood vessels, takes place from the bone bed and not from the soft tissue.

In a further step, the disk-shaped element or the crepe is pushed over the collagen membranes so that the disk-shaped element completely covers the layer sequence formed from the augmentate and the collagen membrane.

Then the disc-shaped element is pressed lightly with a sterile cotton swab, which also presses the augmentation material onto the bone bed so that the different components are securely glued together. In this context, it is important that the disc-shaped element or the crepe is mature, ie the coagulation has progressed far enough and that sufficient liquid has been squeezed out of this element.

The wound is then closed without tension, saliva-proof and with fine sutures. Depending on the composition, an augmentation produced according to the invention and implanted as described above can be loaded at the earliest 4 to 5 months after the implantation has taken place or is suitable for the insertion of dental implants.

In addition, FIG. 2 again shows in several illustrations a schematic representation of the method with the individual method steps A to M for producing an augmentation 1 designed according to the invention. In method step A, a sample 2 of autologous, peripheral venous blood is taken from a patient. In step B, this sample 2 is filled into a blood collection tube 3 containing sodium citrate, thereby stopping the coagulation of the blood permanently, but reversibly. Next, in step C, the blood sample 2 is centrifuged at a rotary speed of 1900 rpm for a period of 8 minutes.

As a result of the centrifugation carried out, blood serum and blood plasma are separated and two blood plasma fractions 4, 5 are formed, namely on the one hand a first light, fibrin-rich 4 and a second heavy, thrombocyte-rich blood plasma fraction 5. The two different blood plasma fractions 4, 5 are in process step D obtained by specifically pipetting off the blood serum. Any cells, mostly erythrocytes (hematocrit) and the buffy coat (leukocytes) are discarded and not used for the rest of the procedure. In step E, the two different blood plasma fractions 4, 5 are kept in suitable blood plasma tubes. At the beginning of an operation, the two blood plasma fractions 4, 5 are provided in process step F in separate small glass bowls 6. Here, the first light, fibrin-rich blood plasma fraction 4 is activated with calcium chloride, so that coagulation processes begin within this blood plasma fraction 4 . In this case, temperature control is not necessary or superfluous because, if required, coagulation can be accelerated at a later point in time by dipping the augmentate 1 then produced into the first blood plasma fraction 4 .

After the surgeon has obtained autologous bone material 7 from the patient, as shown in step G, this autologous bone material 7 is placed in step H in a metal bowl 9, which also contains bone substitute material 8, in particular xenogeneic, particularly preferably porcine or bovine bone substitute material. filled, with care being taken to ensure that the autologous bone material 7 and the bone replacement material 8 do not come into contact with one another.

Then at least part of the second thrombocyte-rich blood plasma fraction 5 is activated with calcium chloride and also filled into the metal bowl 9 and initially mixed exclusively with the bone replacement material 8 for a maximum of 30 s. If this mixing process were not stopped after 30 s at the latest, the polymerization or concatenation of the fibrin would be destroyed.

Then, in step I, the bone replacement material 8 mixed with the second platelet-rich blood plasma fraction 5 is mixed with the autologous bone material 7 in a ratio of 50:50% by volume and, as shown in step J, an augmentation 1 corresponding to the existing requirements for size and shape shaped.

In this case, the augmentation 1 is modeled manually with a suitable instrument and possibly with the aid of a negative mold and/or a system for the additive production of a shaped body in a suitable manner for 30 to 60 s as required.

Approximately 120 to 240 s after the start of the mixing process, the coagulation has already progressed to such an extent that the shaped augmentate 1 has the consistency shown in step J and can be gripped with tweezers and processed further in almost any way. And to further increase the stability, the augmentate is again immersed in the still liquid second platelet-rich blood plasma fraction 5 for about 15 s. Here, the thrombocytes can cross-link one another with fibrinogen monomers via a special receptor, in particular glycoprotein IIb/IIIa, so that plasmatic coagulation is not required for this.

In an optional method step K, the augmentation product 1 produced is treated with at least part of the second platelet-rich blood plasma fraction 5, for example Immersion, coated or coated. About five minutes after the start of its manufacture, the coated augmentation material 1 has assumed the consistency and shape shown in method step L and can be inserted directly into a bone defect or used for the corresponding reconstruction or for the production of a bone reconstruction.

If the augmentate 1 does not yet have the desired consistency, for example if it cannot be grasped with tweezers in a suitable manner, it can first be brought into contact again with the first, fibrin-rich blood plasma fraction or with the liquid autologous supernatant contained in the metal bowl 9 . Here, the augmentation material 1 is preferably immersed in the first blood plasma fraction 4 for a few seconds in order to accelerate the fibrin crosslinking in the first light, fibrin-rich blood plasma fraction 4 and to optimize the quality of the fibrin crosslinking. The prerequisite for this is that the first light, fibrin-rich blood plasma fraction 4 has not yet coagulated at this point in time. Alternatively, some excess liquid from augmentation 1 can also be used.

Following this, the first fibrin-rich blood plasma fraction 4 forms a matrix within 3 to 10 minutes and solidifies into a cake-like element. This cake-shaped element is pressed into a membrane in process step M, whereby the fibrin concentration is increased and unnecessary liquid is removed from the fibrin. A flat membrane is usually formed in the form of a disc-shaped element, the diameter of which depends on the diameter of the bottom of the glass bowl in which the first fibrin-rich blood plasma fraction is stored and on the amount of platelet-rich blood plasma obtained. Furthermore, the thickness of the disc-shaped element is adjusted by suitable adjustment and/or variation of the pressure exerted on the element and the duration of the pressing process. According to the embodiment described here, a 1 to 2 mm thick disk-shaped element, a so-called crepe, is produced, which element can be used as an additional adhesive element and/or for soft-tissue lining.

3 shows a further suitable special development of the method according to the invention. What is essential about this embodiment is that the platelet Rich blood plasma already in the sample tube 3, which is also called a centrifuge tube, since it is used to centrifuge the blood sample 2, as shown in FIG. 3A, is separated by a separating gel. During centrifugation, the separating gel resides within the buffy coat, forming a stable physical barrier that isolates platelets and blood plasma in the upper part of tube 3, while nearly all erythrocytes and most of the neutrophils are bound in the lower part . In this case, coagulation is stopped by adding sodium citrate, with the sodium citrate preferably being brought into contact with the sample for about 9 minutes.

In the step shown in FIG. 3B, a syringe 10, which has a volume of 5 ml, is first raised with 0.5 ml of calcium gluconate and then, as shown in FIG. 3C, the remaining syringe volume is filled with platelet-rich blood plasma from the centrifuged sample 2 filled up.

In the step according to FIG. 3D, allogeneic, xenogeneic and/or synthetic bone replacement material 8 is mixed with about 1 ml of the mixture containing calcium gluconate and platelet-rich blood plasma, and this mixture is finally mixed with autologous bone material 7, as shown in FIG. After about 2 minutes, a comparatively solid structure forms, as shown in FIG. 3E, which later forms the augmentation 1 .

Now, as shown in FIG. 3F, the remaining part of the mixture, which contains calcium gluconate and platelet-rich blood plasma, is transferred from the syringe into a bowl and the previously created structure is immersed in the remaining part of the mixture for about 30 s and thus activated as shown in Figure 3G. After a further 3 to 5 minutes, as can be seen in FIG. 3H, the platelet-rich blood plasma in the dish is pressed as required and the membrane shown in FIG. 3I is thus produced.

The main advantage of the method shown in FIG. 3 is that comparatively high-quality platelet-rich blood plasma (PRP) is used, since the use of a separating gel allows the number of thrombocytes to be adjusted relatively precisely. In addition, the process has advantages with regard to the required work steps, as the usual pipetting is no longer necessary. Since the blood taken from the patient is initially anticoagulated, this is reactivated with calcium gluconate, as shown in FIG. 3B. Reference List

1. Augmentation

2. Blood test

3. Blood Collection Tube

4. First fibrin-rich blood plasma fraction

5. Second platelet-rich blood plasma fraction

6. Glass bowl

7. Autologous bone material

8. Bone Substitute Material

9. Metal shell

10. Syringe

Claims

patent claims

1. A method for producing an augmentation (1) having a composite material for the reconstruction and regeneration of at least partially lost bone substance, for filling bone defects and/or for optimizing a bony tooth implant bed of a patient with the steps:

Mixing a sample (2) of autologous peripheral venous blood taken from the patient and adding sodium citrate to reversibly stop blood coagulation,

Preparation of blood plasma by centrifuging and obtaining at least a first light, fibrin-rich and at least a second platelet-rich blood plasma fraction (4, 5) from the blood plasma, characterized by the steps

adding calcium chloride to the first blood plasma fraction (4) separate provision of autologous bone material (7) and allogeneic, xenogeneic and/or synthetic bone replacement material (8) in a vessel,

Preparation and activation of a mixture by adding calcium, especially calcium chloride, to the second blood plasma fraction (5)

Soaking the bone replacement material (8) with the mixture,

Producing a mixture by mixing the bone replacement material (8) soaked with the mixture with the autologous bone material (7) and forming the augmentate (1) from the mixture.

2. The method according to claim 1, characterized in that an antibiotic, in particular clindamycin or doxycycline, is added to the autologous bone material (7) provided in the vessel.

3. The method according to claim 1 or 2, characterized in that porcine, bovine, allogeneic, xenogeneic and/or synthetic bone substitute material (8) with a grain size of 0.25 to 1 mm is provided.

4. The method according to any one of the preceding claims, characterized in that a mixture containing 25-75% by volume of autologous bone substitute 17) is produced by mixing the mixture with the autologous bone material (7).

5. The method as claimed in one of the preceding claims, characterized in that the blood sample (2) mixed with sodium citrate is centrifuged horizontally at a rotational speed of 1250 to 2400 rpm, in particular 1900 rpm.

6. The method according to any one of the preceding claims, characterized in that xenogeneic bone replacement material (8) made of porcine or bovine bone is provided.

7. Method according to one of the preceding claims, characterized in that the mixture is mixed with the autologous bone material (7) for no longer than 30 seconds.

8. The method according to any one of the preceding claims, characterized in that the augmentation (1) is formed at least temporarily by manual deformation and/or by deformation using a negative mold.

9. The method according to any one of the preceding claims, characterized in that the mixture for 15 to 60 s is formed into the augmentation (1).

10. The method according to any one of the preceding claims, characterized in that the augmentation (1) is at least partially shaped, compressed, cut and/or rolled.

11. The method according to any one of the preceding claims, characterized in that the augmentation material (1) is at least temporarily brought into contact with the second plasma fraction mixed with calcium chloride.

12. The method according to any one of the preceding claims, characterized in that the augmentation (1) and / or liquid from the augmentation (1) to accelerate and improve coagulation and / or crosslinking is at least temporarily brought into contact with the first fibrin-rich blood plasma fraction (4) mixed with calcium chloride.

13. The method according to any one of the preceding claims, characterized in that at least part of the first fibrin-rich blood plasma fraction (4) mixed with calcium chloride is pressed to form a membrane.

14. The method as claimed in claim 13, characterized in that a membrane with a thickness of 1 to 2 mm is produced.

15. Method according to one of the preceding claims, characterized in that at least part of the first fibrin-rich blood plasma fraction (4) mixed with calcium chloride is formed, folded and/or pressed into a volume and/or soft tissue transplant.

16. The method according to any one of the preceding claims, characterized in that the augmentation (1) is covered with an absorbable xenogenetic, allogeneic or synthetic collagen membrane.

17. Method according to one of the preceding claims, characterized in that the augmentation (1) is covered at least in regions with a collagen membrane, in particular with a pericardial membrane from a pig (double to 16?)

18. The method according to claim 13, characterized in that the augmentation (1) is covered at least in regions with the membrane produced from the first fibrin-rich blood plasma fraction (4) mixed with calcium chloride.

19. The method according to claim 16, characterized in that the collagen membrane is at least temporarily brought into contact with the first fibrin-rich blood plasma fraction (4) mixed with calcium chloride.

20. The method according to any one of the preceding claims, characterized in that the first fibrin-rich blood plasma fraction (5) is at least partially brought into contact with at least part of the autologous bone material (7) in such a way that platelet cellular hemostasis is initiated at least temporarily.

21. Bone replacement piece with an augmentation (1) produced using a method according to at least one of the preceding claims.

22. Bone replacement piece according to claim 19 for replacing at least partially lost jaw bone substance of a patient.