Device for use with therapeutic or surgical instruments, implants and equipment therefor

An antibacterial device has a surface with a layer that releases ions with an antibacterial effect, e.g. silver ions. The effect of silver is strongly antiseptic even in the bound state, since silver ions contained in the oxide layer of the metal surface exert a blocking effect on the thiol enzymes in the microorganisms. By using a layer that releases silver ions, the risk of bacterial infections can be clearly reduced. Other ions with an antibacterial effect, e.g. copper, can be used by themselves or together with the silver ions. The device may also have a layer having a matrix that is preferably made of plastic. The matrix serves to continuously release silver ions or other ions with an antibacterial effect. With a continuous release of metal ions, a long-lasting antibacterial effect in the tissue is achieved by the surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred exemplary embodiments of the device according to the invention will be explained below. By reducing the number of bacteria that are present on the implant or instrument surface, the risk of a bacterial infection caused by implants and other medical technology devices is reduced. At the same time, if the surrounding tissue attaches well to the implant, the body's own immune system can be effectively used to defend against bacteria. To reduce the number of bacteria on the implant surface, a physical chemistry surface modification to prevent infection can be used. The approach that is followed in this connection is to prevent the first step of a bacterial infection caused by a medical device (implant, instrument), which is that of adhesion of bacteria to the implant surface. If adhesion of bacteria to the implant surface can be prevented or made more difficult, the risk of a subsequent infection is clearly reduced. This primary adhesion of bacteria can be prevented by means of surface modification. In this connection, the surface energy of the implant surface is changed, by means of suitable surface modification, in such a way that adhesion of bacteria is disadvantageous in terms of energy and biochemistry. In addition, a smooth implant surface is produced, in order to prevent adhesion of bacteria in protected depressions on the surface. Modification of the surface energy is achieved by means of coating the surface, or by modifying the available regions near the surface, for example by means of diffusion or oxidation processes. A smooth implant surface is achieved by means of grinding and/or polishing that precedes surface modification. Possible surfaces are: titanium oxide coating; modified diamond-like carbon coating; hydroxyapatite (HA) coating; calcium phosphate (CaP) coating; tantalum oxide coating; titanium niobium ceramic coating; titanium zirconium ceramic coating; anode oxidation Type II of titanium; embedding of carbon in the implant steel; and magnesium coating. Such a surface coating can be provided, for example, on implants for osteosynthesis such as plates, screws, pins for external fixators, bone marrow nails. Likewise, such coatings are suitable for implants for joint replacements, such as knee replacements or hip replacements. Such a coating is also advantageous for implants used in the area of the spinal column. In an alternative embodiment of the device according to the invention, the antibacterial effect of metal ions, particularly silver ions, is utilized. Starting from a defined ion concentration, the bacteria present on the implant surface are killed off, and an infection is therefore prevented. In order to achieve a continuous antibacterial effect on the implant surface, a continuous release of metal ions is preferred. A substance that releases silver ions or other ions with an antibacterial effect is applied to the implant surface for this purpose. This can be done in a matrix, usually a plastic, or also a ceramic (HA or ICP). The particles located on the surface continuously give off silver ions. Metal implants can be completely or partially provided with a surface coating that releases ions. In the case of non-metallic implants, for example those made of resorbable or non-resorbable plastics, that is particularly polylactides PLA and poly-L-lactides PLLA, polyetheretherketone (PEEK), ultra high molecular weight polyethylene (UHMWPE), the substance that releases ions can be mixed into the implant material directly, during the production process. This is likewise the case for ceramics, such as tricalcium phosphate (TCP) or hydroxyapatite (HA). In addition to the implants mentioned above, such substances that release ions can also be mixed into bone cement (polymethylmethacrylate PMMA) and ceramic cement, as well as other substances capable of flow. Likewise, it is possible to mix ion-releasing substances into plastic implants in the orthopedic area. Another alternative approach takes advantage of the fact that bacteria react to electrical charge. Therefore the adhesion process is influenced by contact of the bacteria with an electrically charged surface. By applying a suitable electrical voltage to the implant, adhesion of bacteria to the implant surface can be prevented, i.e. the surface can be “flushed”. For this purposes, it is possible to connect a suitable voltage source to the implant after implantation, via a suitable adapter. In this connection, both a voltage that is constantly maintained and short-term application of a voltage are suitable. Also, an alternating voltage can be applied. The above examples for the production of an infection-resistant, biocompatible surface can also be used for instruments and accessories in the operating room. Maintaining sterile conditions in the operating room is an important prerequisite for avoiding bacterial infections in the hospital. In order to reduce the bacteria count on the instruments and trays used in the operating room, the surfaces of the instruments and trays are modified in such a way that bacteria do not adhere to them, or adhere in reduced number, and/or do not survive on the surface. It is also possible to use ion-releasing substances for plastic trays, plastic handles, and plastic instruments. Modifications of the surface can also be used in combination with one another. Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.