DE3704089C2 - - Google Patents

Description

The invention relates to a bone endoprosthesis as they emerges from the preamble of claim 1. With such implants made of metal, can be made from ceramic or from hydroxyapatite, Very often the problem arises that after the implantation surrounding tissues are not in the desired and required Way grown together with the implant and a stable relationship of living tissue with non-living materials. It is also disadvantageous that heterologous implants in the course of Can relax time, so that a replacement and thus a new one Surgery becomes necessary. This can be caused by micro movements of the implant apply, which reverses an atrophy of the implant effecting tissue.

To prevent the implant from loosening, an attempt is made to to stop the atrophy of tissues and cells. This he follows with the help of so-called growth factors. Your most important Property is that they have specific cell types specific to the cell can stimulate division and proliferation. The one with the best under The growth factor is the Platlet Derived Growth Factor (PDGF), which on mesenchymal connective tissue cells such as fibroblasts, Mitogenic and stimulated osteoblasts, glial cells and the like this to growth. PDGF also has chemotactic properties because it is the only substance known to date is to move the otherwise relatively sluggish fibroblasts towards the location of the highest concentration of the growth factor spread out. PDGF is effective in very low concentrations.

The use of porous impregnated with growth factors and other active substances Materials such as hydroxyapatite or ceramic as Bone replacement is known from DE-OS 30 07 446. The growth factor is supposed to be the bones promote new growth and rapid growth.

One disadvantage of such an impregnation is that  that the growth factor is broken down too quickly. Because of the low half-life, which in PDGF is only about two minutes is therefore the growth-promoting effect on one Time immediately after the operation is limited, so that the Atrophy can only be counteracted temporarily. Becomes in contrast, the growth factor is permanently applied to the implant, this could be due to a possible continuous stimulation lead to excessive tissue growth.

Furthermore, from DE-OS 33 31 091 a joint endoprosthesis known, which consists of a windowed hollow body. they can be largely or completely with absorbable biological Filled material that unites with the bone can form a firm bond.

After inserting the implant into the organism there is one individual supply of active substances, such as the so-called growth factors, antibiotics or the like, not feasible. Atrophy of tissues and cells can therefore not be counteracted with this implant. Long-term effective support of the bone and tissue growth are not made with this.

In addition, in DE-PS 30 12 224 self-closing injection closures made of elastic silicone rubber, for example for the regular introduction and removal of liquids in the human body or for regular injection of drugs.

Based on the bone endoprosthesis mentioned above it is an object of the invention to the receiving device design that they are repeatedly reliable and safe with a Injection needle can be applied.

This object is achieved by the characterizing Part of claim 1 specified features solved.  

The invention has the advantage that the injection needle through the inlet opening is directed precisely onto the sealing membrane becomes.

The invention also has the advantage that even after the onset of Implant into the organism by transcutaneous injection of a growth factor dissolved in a carrier medium into the channel system and simply by forwarding it to the tissue subsequent supply of growth factors is feasible. A new operation is not necessary. The injection can with a cannula at any time and any number of times surgery. In contrast to permanent impregnation the dose of the growth factor can be the current one Situation to be adjusted. The channel system creates the possibility distribute the growth factor in a targeted manner.

Another advantage of the invention is that the Antibiotics are equally supplied around the implant if necessary. Here too can the dosage and the time of application without significant Impairment of the patient because there is only one  transcutaneous injection into the receiving device of the implant must be carried out.

In addition, the invention is also very well suited to Hor mones, such as estrogens, so that the mine Ralization of the bones can be promoted. As another sub punch, which is dissolved in the body-compatible liquid carrier medium medication can be considered. Furthermore, by Injection of a contrast medium repeats the progression of the Healing process and the waxing process with the help be monitored by an x-ray device.

The growth factors, antibiotics, Medicines, hormones, and contrast agents are used briefly referred to as active substances.

Another embodiment of the invention is that the Reception facility by at least one raised approach mar is. The recording device can thus be used for an x-ray Illumination clearly localized and the cannula precisely attached be set.

In particular, it is advantageous that the receiving device as Stutzen is formed, the outline of which is clearly a localization allows. Further configurations of the receiving device are shown in Subclaims laid down.  

A particularly preferred embodiment of the invention exists in that the receiving device releasably with the rest of the Im plantate is connected. Thus, the receiving device can be removed from the organism when the rest of the implant is closed is connected peacefully with the surrounding tissue.

This releasable connection is preferably produced in that the implant at the entrance to the canal system with an internal thread and the receiving device with a corresponding external thread de is provided. The first when inserting the implant in the organism can be screwed to this receiving device unscrewed and removed in a relatively simple procedure if there is no further supply of active substances seems necessary.

To prevent any microorganisms from entering to prevent in the canal system and the organism, it is before partial that the channel system with Ste rilfilter is provided. In the case of a detachable recording device It is advisable to use the sterile filter in the receiving device order.  

In the embodiment of the invention described above, it is expedient that the receiving device is detachable and made of metal is trained.

In the following the invention based on several execution examples further described.

Fig. 1 shows purely schematically a longitudinal section through a first bone-endoprosthesis

Fig. 2 shows schematically a longitudinal section through a second bone endoprosthesis and

Fig. 3 shows schematically a longitudinal section through a third bone endoprosthesis.

As illustrated in FIG. 1, a first implant 1 , which in the example shown here is designed as a thigh prosthesis, is provided with an internal channel system 2 . This leads from a receiving device 3 to a plurality of outlet openings 4 on the surface of the first implant 1 . To simplify the illustration, the outlet openings 4 in FIG. 1 are evenly distributed, although under certain circumstances it may be expedient to provide a different distribution. For the same reason, the channel system 2 is limited to the reproduction of a single central channel 5 and branches 6 extending therefrom. In the example shown, the first implant did 1 and the receiving device 3 are integrally formed. In such an embodiment, the first implant 1 and the receiving device 3 are made of metal, for example. The channel system 2 is drilled into the implant.

As an alternative, it is also possible to use the channel system Arrange cables on the surface of the implant (not shown). This design of the channel system is special useful for a flat implant.

The left side of the first implant 1 is coated with a porous material 18 exclusively for better illustration of the invention. The outlet openings 4 thus open into the po rous material 18th As the right side of the first implant 1 illustrates, the outlet openings 4 can also open directly on the surface of the first implant 1 .

The receiving device 3 is prominently formed on the first implant 1 so that it can be distinguished from the rest of the implant by X-ray and uniquely located. The inlet opening 7 of the receiving device is provided with a sealing membrane 8 , which can be made of silicone rubber, for example. A sterile filter 9 for filtering microorganisms lies behind it at a safety distance. As will be described below, the sealing membrane 8 is pierced by an injection cannula 10 during a transcutaneous injection, the safety distance preventing damage to the sterile filter 9 .

The inlet opening 7 of the receiving device 3 is provided in the example shown with an internal thread 11 , which has the task of enabling a detachable connection to a pressure pipe 13 with a corresponding external thread 12 . The pressure tube 13 , which is only required in the case of an injection under pressure, and which receives the injection cannula 10 , is also introduced transcutaneously.

The receiving device 3 is designed as a radiographically visible nozzle.

For further understanding, the application of the invention is described by way of example below. The implant 1 is inserted in the usual way during an operation in the organism (not shown). Because of the channel system 2 and the practically repeatable access via the receiving device 3 , a variety of possibilities for targeted spatial, timely and repeatable supply of the adjacent tissue with active substances are created. A liquid carrier medium with the active substance in question is injected transcutaneously with the help of the injection cannula 10 , alternatively using the detachable pressure tube 13 . After each injection, the Injektionskanü le 10 and the pressure tube are removed from the organism so that the subject does not experience any disability.

The insertion of the injection cannula 10 and possibly the pressure tube 13 into the receiving device 3 is carried out under X-ray monitoring, which is facilitated by the raised, characteristic shape of the receiving device 3 . In the case of a flush design of the receiving device 3 , this can also be carried out by other radiologically identifiable markings, such as humps or the like (not shown).

In Fig. 2 a variant of the implant 1 'is illustrated purely schematically. Here are two separate and independent channel systems 2 , 2 ', each with its own receiving device 3 and 3 '. The outlet openings 4 , 4 'of the two channel systems 2 , 2 ' are arranged in such a way that certain adjacent tissue regions (not shown) can each be supplied with the desired active substances in a targeted and independent manner. In FIG. 2, the left channel system 2 is assigned to the left implant side and the right channel system 2 'to the right implant side for the sake of a clear representation.

In addition, Fig. 2 illustrates in an area 14 of the implant 1 'by way of example that the density of the outlet openings 4 ' on the surface of the implant 1 'can be of different sizes in order to be able to supply different amounts of the active substances to predetermined regions. This purpose could also be achieved by the fact that the outlet openings 4 , 4 'are under different sizes (not shown).

In Fig. 3 a third example is shown of an implant. It consists of a porous material, such as hydroxyl apatite. The result of this is that the active substances injected into the channel system 2 '' can pass through the walls of the channel system 2 '' into the implant, which is indicated purely schematically by arrows 15 in the form of a star. In this way, the substances are evenly and finely distributed and can exert their effect optimally in the implant and on the surface of the implant. It may therefore be superfluous that the channel system 2 '' is provided with openings emerging directly on the implant surface, as shown schematically in Fig. 1 on the right side of the implant. As FIG. 3 shows, it is sufficient at such a material rather, that the channel system at a predetermined distance below the surface of the implant 1 '' ends.

Further shown in Fig. 3 schematically shows that the recording device 3 '' is detachably connected to the implant 1 '', respectively. For this purpose, the implant 1 '' at the entry opening 7 of the channel system 4 '' is provided with an internal thread 16 . The formed as a separate part receiving device 3 '' be sits a corresponding external thread 17 and can therefore be screwed into and out of the internal thread 16 . The intake device 3 '', which is otherwise provided with a sealing membrane 8 and a sterile filter 9 , can be made of a different material than the implant 1 ''. Metal is preferably used.

In accordance with the in Figs. 1 and 2, the "recording device 3" is input side with an internal thread 11 for acceptance on a pressure pipe provided.

The details described in connection with the figures The invention can of course be combined with one another will.

Claims (8)

1. Bone endoprosthesis which has a channel system starting from a receiving device with outlet openings distributed over the implant surface, characterized in that the receiving device ( 3, 3 '' ) has an inlet opening ( 7 ) which is closed by a penetrable sealing membrane ( 8 ) is and that at the output of the receiving device ( 3, 3 '' ) a sterile filter ( 9 ) is arranged. 2. Bone endoprosthesis according to claim 1, characterized in that the receiving device ( 3 '' ) is detachably connected to the rest of the implant ( 1 '' ). 3. Bone endoprosthesis according to claim 1 or 2, characterized in that the implant ( 1 '' ) at the entrance to the channel system ( 4 '' ) with an internal thread ( 16 ) and the receiving device ( 3 '' ) with a corresponding external thread ( 17 ) is provided for producing a detachable screw connection. 4. Bone endoprosthesis according to claim 1, characterized in that the receiving device ( 3 ) and that implant ( 1 ) are integrally formed. 5. Bone endoprosthesis according to one of the preceding claims, characterized in that the receiving device ( 3 , 3 '' ) is marked by at least one with respect to the implant ( 1, 1 '' ) raised approach. 6. Bone endoprosthesis according to claim 5, characterized in that the receiving device ( 3, 3 '' ) is designed as a socket, the outline of which clearly allows X-ray localization. 7. Bone endoprosthesis according to one of the preceding claims, characterized in that the receiving device ( 3, 3 '' ) is provided on the input side with a sealing device for tight but detachable receiving a pressure tube ( 13 ) for a pressure injection. 8. Bone endoprosthesis according to claim 7, characterized in that the sealing device consists of an internal thread ( 11 ) for receiving a corresponding external thread ( 12 ) on the pressure tube ( 13 ).