GB2557900A

GB2557900A - Prosthetic device and related medical system capable of deep prosthetic disinfection and pain control

Info

Publication number: GB2557900A
Application number: GB1617750.3A
Authority: GB
Inventors: Bandinelli Mauro; Mastantuono Fabio; Mastantuono Marco
Original assignee: IDS Ingegneria dei Sistemi SpA
Current assignee: IDS Ingegneria dei Sistemi SpA
Priority date: 2016-07-07
Filing date: 2016-10-20
Publication date: 2018-07-04
Also published as: GB201617750D0; GB201612064D0

Abstract

A prosthetic or implantable device comprises a susceptor material c, such as ferromagnetic or superparamagnetic nanoparticles, which can be heated upon targeted application of a variable electromagnetic field. The heated susceptor material c may function to prevent or reduce infections either on or in the proximity of the device caused by a bio-film of sessile bacteria. The susceptor material c is preferably sandwiched in a three layer structure which coats the device, having a dielectric layer b proximal to the device surface and an external protective coating d formed by anodic oxidation. The layer of susceptor material may have a variable thickness or discontinuities in the form of a specific pattern to optimise heat delivery and distribution. Also disclosed is a biocompatible cement g with ferromagnetic or superparamagnetic nanoparticles dispersed in the cement g, and a variable frequency power generator (fig 1b,c) connected to a coil (fig 1e) or antenna (fig 1f) for targeting radiation at the device or cement.

Description

(56) Documents Cited:

GB 2520960 A WO 2014/045312 A1 US 20050021088 A1

A61F 2/02 (2006.01) A61N 2/00 (2006.01)

EP 2740445 A1 US 20080319247 A1 (71) Applicant(s):

Fabio Mastantuono

Via della Balduina 135, 00136 Rome, Italy

Marco Mastantuono

Via della Balduina 135, 00136 Rome, Italy (58) Field of Search:

INT CL A61F, A61K, A61L, A61N Other: WPI, EPODOC

IDS Ingegneria dei Sistemi S.p.A.

Via Enrica Calabresi, 24, Pisa, 56121, Italy (72) Inventor(s):

Mauro Bandinelli Fabio Mastantuono Marco Mastantuono (74) Agent and/or Address for Service:

Fabio Mastantuono

Via della Balduina 135, 00136 Rome, Italy (54) Title ofthe Invention: Prosthetic device and related medical system capable of deep prosthetic disinfection and pain control

Abstract Title: Prosthetic or implantable device with heated susceptor sterilisation (57) A prosthetic or implantable device comprises a susceptor material c, such as ferromagnetic or superparamagnetic nanoparticles, which can be heated upon targeted application of a variable electromagnetic field. The heated susceptor material c may function to prevent or reduce infections either on or in the proximity ofthe device caused by a bio-film of sessile bacteria. The susceptor material c is preferably sandwiched in a three layer structure which coats the device, having a dielectric layer b proximal to the device surface and an external protective coating d formed by anodic oxidation. The layer of susceptor material may have a variable thickness or discontinuities in the form of a specific pattern to optimise heat delivery and distribution. Also disclosed is a biocompatible cement g with ferromagnetic or superparamagnetic nanoparticles dispersed in the cement g, and a variable frequency power generator (fig 1b,c) connected to a coil (fig 1e) or antenna (fig 1f) for targeting radiation at the device or cement.

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PROSTHETIC DEVICES AND RELATED MEDICAL SYSTEM CAPABLE OF DEEP

PROSTHETIC DISINFECTION AND PAIN CONTROL

Field of Invention

This invention relates generally to the medical prosthetic field and it concerns a system based on susceptors capable of overcoming prosthesis infection.

and and

Preceding patents referring to techniques and methodologies for preventing infections of prostheses and implants are:

US 2010/0174346 Al publication date July 8 2010 and previous related US application System devices and methods including actively-controllable sterilizing excitation delivery implants examines various modalities and methods for sterilization but does not refer to susceptors ferromagnetic/super-paramagnetic nano-particles .

US 2010/0256607 Al publication date October 7 2010 previous related US application Method and apparatus for automated active sterilization of fully implanted devices does not contemplate susceptor materials and coatings and even if it concerns implantable devices it achieves the function of sterilization by means of unspecified implanted active device. US 2010/0204551 Al publication date August 12 2010 Detection, prevention and treatment of infections in implantable device and previous related US application does not refer to susceptors. Where it examines coating with nano particles these are used as releasers of antibiotics, cytotoxins and other medicines that act against bacteria.

US 2010/0204802 Al publication date August 12 2010Medical Devices does not contemplate susceptor material and coatings of implantable devices; it examines a plurality of sterilization modalities and mechanisms, chemical, biological, in a general way without identifying any distinctive element considered in the present invention even if it concerns implantable devices.

Background of the Invention

The infection of prostheses or devices implanted in the human body is one of the most feared circumstances by physicians and patients. Referring specifically to the hip prosthesis for example these infections are quite frequent with a percentage varying from 0.5 to 5% of the cases.

Possibility of infections increases in the event of reimplantation or in the presence of risk factors like a previous surgery, local hematoma, recurring infective illness or generalized bone illness. Streptococcus is frequently isolated in this type of infection in comparison to other kinds of microorganisms. Generally a fever occurs in association with an immediate deterioration of the prosthetic area. These infections are more likely in patients with immunosuppression due to inflammatory arthropathy or transplantations and in patients with recurring episodes of bacteremia .

Prosthesis infections are generally rooted inside a bio-film that forms on the surface of the implanted prosthetic material.

The bio-film is generally made of sessile bacteria. As soon as the bacteria colonies develop, sessile bacteria detach from the bio-film and spread out in the form of planktonic bacteria capable of scattering and colonizing the nearby areas. The bio-film generally grows slowly and the bio-film itself is able to protect bacteria making them less sensitive to antimicrobial agents.

THERAPY APPLIED TO DATE

The standard antibiotic therapy is able to relieve the symptoms caused by planktonic bacteria released by the biofilm but it is ineffective in killing bio-film bacteria.

In order to get rid of sessile bacteria removal of the implant is almost always necessary in addition to bacteria elimination therapy.

Nowadays prosthetic device infection therapy is performed through both targeted antibiotic therapies and surgical strategies in two forms: 1) Re-implant in two stages (using a temporary antibiotic spacer) or 2) implant in one stage (immediate implant substitution).

In case of infections at an early stage it is possible to try to save the prosthetic device through deep surgical cleaning and an extended antibiotic therapy.

Infection, once more frequent is nowadays a rarer event due to appropriate environmental and antibiotic prophylaxis.

The two problems in the prosthetic field that this invention aims to solve are (i) to prevent, remove or control infections which may occur on the prosthesis or in its proximity following the implant and (ii) the reduction of pain generated in case of infection from the implanted prosthetic device.

Disclosure of Invention

The present invention proposes a coating layer for implantable and prosthetic devices which surrounds the device, in which a susceptor film or susceptible nano particles are placed, which is capable of being heated when subjected to a time-variable electromagnetic field applied to the area of the implanted prosthesis. Also the cement layer applied to fix in place the prosthetic device can be loaded with susceptible nanoparticles and heated through the same electromagnetic field. The prosthetic or implantable device can be used with an electromagnetic field directive source specifically built in order to transfer energy to susceptors, in a calibrated way, in order to safely obtain, through heating, the sterilization of prosthetic device and any surrounding biofilm.

The invention provides a prosthetic or implantable device comprising a susceptor. The susceptor may comprise a layer of micro or nanometric thickness which coats the device. The susceptor layer may further be separated from the surface of the device by a dielectric layer. The susceptor layer may have a variable thickness and /or may be discontinuous.

The susceptor may comprise ferromagnetic or super-paramagnetic nano-particles .

The prosthetic or implantable device may further comprise a protective layer on the external surface of the susceptor. This protective layer may be an oxidized layer formed by anodic oxidation, optionally with a thickness of 0.5 to 1 micron.

The invention also provides a biocompatible cement comprising ferromagnetic or super-paramagnetic nano-particle susceptors

dispersed	in	the	cement.	The	cement	can	be used	with
prosthetic	or	implantable	devices including	those	of	the
invention.	In	this	way infection	of the	cement link	between

the device and bodily tissues can be treated or prevented using electromagnetic radiation as described herein.

The susceptor material used in prosthetic or implantable devices and biocompatible cement according to the invention may be a conductor selected from the group consisting of:

a) metals, for example titanium;

b) metal alloys, for example stainless steel, Cobalt Chromium Alloys or TI6A14V;

c) graphite;

d) carbon; or

e) pyrocarbon.

The invention also provides a power generator for use with the prosthetic or implantable devices or the biocompatible cement of the invention, which can deliver variable frequencies in the range AC (range of kHz), RF (range of MHz), and / or MW (range of GHz), and capable of variable power emission, the generator being connected to a coil or an antenna system that is able to concentrate, through the body, the emitted radiation on all or part of the susceptor comprised in the device or cement.

The invention further provides a method of sterilizing a prosthetic or implantable device and/or a biocompatible cement according to the invention, comprising subjecting the susceptor comprised in the device or cement to a variable electromagnetic field.

The invention also provides a method of treating infection of a prosthetic or implantable device and/or a biocompatible cement of the invention, comprising subjecting the susceptor comprised in the device or cement to a variable electromagnetic field.

The invention further provides a susceptor material for use in treating or preventing infection of a prosthetic or implantable device and/or a biocompatible cement according to the invention, wherein the susceptor material is comprised within the device and/or cement.

The infection is generally bacterial infection but may be any infection that can be prevented, arrested or treated by the use of heat.

The above methods may further be combined with a washing step to avoid overheating of surrounding tissue. The washing may agents. Any suitable be used, typically a preferred also help to remove infectious biocompatible washing solution can sterile solution. Ozonated water or liquid is a washing solution.

The susceptor material can be embedded in a three-layer structure, the internal layer (proximal to the prosthetic or implantable device) being a dielectric layer having the function of dielectric insulation with respect to prosthetic device, and the external layer prosthetic or implantable device) having the function of mechanical protection of the susceptor material from the external biological environment.

the distal from the

In the invention the terms implantable device and prosthetic device may be used interchangeably, meaning both types of devices. The term implantable device includes any surgical implant, including those comprising or consisting of a bone screw, one or more bone plates and/or spine components.

Brief Description of Drawings

For a more complete explanation of the present Invention and the technical advantages thereof_r reference Is now made to the following description and the accompanying drawings In which:

Figure 1 shows the AC/RF/MW (Alternating Currents / Radio Frequency / MlcroWave) Induction system scheme.

Figure 2 shows a schematic representation of a prosthetic device with surrounding susceptor layers.

Figure 3 shows details of a patterned susceptor film.

Figure 4 shows different types of source of electromagnetic energy: antennas or induction coils.

Figure 5 shows another prosthetic device with different kinds of susceptors.

Detailed Description of Invention system comprising

The subject of the invention is susceptor material to be used implantable devices, which is used with an electro-magnetic energy source system capable of controlled heating of said susceptor material. A susceptor includes withing prosthetic or any capable of being heated electromagnetic field.

material variable absorb when subjected to a The susceptor can electromagnetic energy and convert it to heat. This heat is useful for killing or arresting the growth of any bacteria on the surface of or near to the prosthetic or implantable device, particularly biofilm bacteria that are otherwise hard to treat. In this way, sterilization of the device and/or treatment or prevention of infection may be achieved. Heating should be to a minimum of 42°C. The temperature can be optimized depending on the infectious agent to be treated. Susceptor materials may form a coating of prosthetic devices with three principal modes of implementation: 1) in the form of a continuous layer coating the prostethic device (thin film); 2) in the form of ferromagnetic/super-paramagnetic nano-particles used in doping of dielectric materials which compose the superficial portion of prosthetic devices; and/or 3) in the form of ferromagnetic/ super-paramagnetic nanoparticles comprised in adhesive cement for use with a prosthesis (bone cement). Susceptor materials in all three possible implementations, if exposed to a specific electromagnetic field, almost instantaneously rise in temperature. The electro-magnetic source apparatus is therefore able to transfer heat to the device and any bio-film formed on it, causing a deep disinfection and collateral analgesic effects. The susceptor material can be embedded in a three-layer structure, the internal layer (proximal to the device) being a dielectric layer having the function of dielectric insulation with respect to the prosthetic device, and the external layer (distal from the prosthetic device) having the function of mechanical protection of the susceptor material from the external environment.

In the first implementation, above named thin film, the heating of the layer is caused by resistive losses induced by exposure of coated prosthetic components to an electromagnetic field in the kHz/GHz frequency ranges.

In the second and third implementations, which adopt ferromagnetic/super-paramagnetic nano-particles, the heating of the layers is caused by hysteresis induced by the exposition of coated prosthetic components to an electromagnetic field in the (kHz/MHz) frequency ranges.

The source system is basically composed of a tunable power generator and an antenna system, able to focus the energy, at the required frequency, on the prosthetic device. The energy emission time is selectable by the operator depending on the morphological and physical characteristics of the prosthetic device to be treated. The source system must be able to focus the energy safely on implanted devices.

The thin film described in mode of implementation number 1) is made of conductive bio-compatible material, with a thickness in the micrometric or nanometric range, deposited onto the dielectric surface of the prosthetic device or onto a specific additional insulation layer placed on the prosthetic body if said body is conductive (i.e. prosthetic material in titanium, alloys, carbon etc) . For the purpose of this patent by dielectric material is meant any kind of biocompatible dielectric material, with negligible conductivity and dielectric losses at the frequencies used.

The susceptor material, the specific thickness and the superficial pattern of the susceptor thin film are specifically set in each single prosthetic area aiming to obtain a calibrated homogeneity in temperature. For example, the thickness of the susceptor layer may be variable (e.g. it may be thicker in some parts of the layer and thinner at other points) and/or it may be discontinuous. The variable thickness and/or discontinuity may be in the form of specific patterns to optimize heat delivery and distribution, so to achieve optimal disinfection. It will be appreciated that optimal patterns can be determined for different sizes and shapes of prosthetic or implantable device. In particular the following factors are kept in consideration:

- Biocompatibility with surrounding tissue;

- Morphology of surfaces under the bio-film;

- Workload and wear of the coating for the prosthetic areas;

- Technological compatibility between prosthetic material and coating technique;

- Electromagnetic radiation antenna system of prosthetic device mutual positioning for the disinfection procedure;

The susceptor for the thin film implementation can comprise various conducting materials, metallic and non-metallic, for example pure metal or steel alloys, titanium, graphite, carbon, pyrocarbon, cobalt-chromium alloys, etc. In this implementation mode of the invention the heating of the layer is caused by resistive losses induced by exposition of coated prosthetic components to an electromagnetic field in the (kHz/GHz) frequency ranges.

In the second implementation of the invention, which adopts ferromagnetic/ super-paramagnetic nano-particles, the susceptor material is comprised within a dielectric layer surrounding the prosthetic device. If the prosthetic material itself is made in polymer or ceramic, it is possible to include nano-particles directly in the external layer. In case of metallic prosthetic devices or those having a conductive surface it is possible to incorporate the ferromagnetic/superparamagnetic nano-particles in biocompatible cement or any other dielectric substrate which is attached to the device to create the external layer. This system is particularly suitable for prosthetic devices or their parts characterized by rough surfaces (e.g. screws, nails catching surfaces). Typology, specific dimensions of the nano-particles and nanoparticle dispersion density in the cement can be optimized taking into account the following requirements:

- Biocompatibility with surrounding tissue;

- Morphology of the implantable device surface where the layer is applied;

- Workload and wear of the coating for the prosthetic areas;

- Technological compatibility between the prosthetic material and the coating technique;

- Electromagnetic radiation source antenna system and positioning of prosthetic device - the relative positions can be optimized for the disinfection procedure.

In the third implementation of the invention the ferromagnetic/super-paramagnetic nano-particles are added to biocompatible cement. The bone cement when applied fills the free space between the device and surrounding tissue, e.g. between a prosthesis and the bone, becoming an elastic strong anchorage material and at the same time a susceptor capable (if activated through a magnetic field) to provide sterilization in the surrounding of the cemented zone.

In the second and third modes of invention described above, iron ion nanoparticles FE 304 can be used as biocompatible nano particles. Such nanoparticles are preferred for their high magnetization values and tiny dimension (typically less than 100 nm in diameter) . A further benefit of this type of nano-particle is that it is stable with respect to oxidation. Other ferro-magnetic kinds of nano-particles that can be used include, without limitation, iron, cobalt, samarium-cobalt, and/or neodynium-iron (Nd2Fel4). Lodestone can be preferably used for super-paramagnetic particles. Metal based nanoparticles must be dispersed in protected mode such that they are suitable for administration to a guest biological organism, ensuring that they are protected from oxidation and that the organism is protected from any possible toxicity. This is obtained by coating particles with biocompatible material such as gold, polymers, silica, and activated carbon. In the second and third implementations, which adopt ferromagnetic/super-paramagnetic nano-particles, the heating of the layers is caused by hysteresis induced by the exposure of coated prosthetic components to an electromagnetic field in the KHz/MHz frequency ranges.

In the first and second mode of the invention, the coating of prosthetic devices might be mechanically protected by a highly thermically conductive protective layer with no or minimal electric loss.

Cement suitable for use with the third mode of the invention can include, for example, the typical PMMA (polymetylmethacrylate) bone cement or bioactive cement. To the cement is added a sufficient quantity of ferromagnetic/super-paramagnetic nano-particles to achieve the desired heating. The cement may include:

a) Polymethylmethacrylate;

b) amorphous powder;

c) methylmetacrylate;

d) catalyst;

e) ferromagnetic/super-paramagnetic nano-particles; and/or

f) ferromagnetic/super-paramagnetic nano-particles gold coating.

The nano-particles used in the second and third modes of the invention are used at a suitable concentration to achieve the desired degree of heating when exposed to a suitable magnetic/electromagnetic field. The degree of heating should be sufficient to kill and/or arrest the growth of bacteria on and/or proximal to the device, thereby to achieve sterilization and/or treatment/prevention of infection. It will be appreciated that the required concentration of nanoparticles to achieve the required degree of heating will vary depending on e.g. the type of device (e.g. size, dimensions), the type of nanoparticles and the type/frequency of magnetic field used. The concentration can be optimized for any given device .

The Magnetic/Electromagnetic source is a power generator operating in one of the AC modes (kHz range)/ RF (MHz range) /MW GHz range) with variable emitting power.

Any temporal modulation law is applicable and can be selected for its ability to deliver the temperature increase plan defined by the operator.

The variable frequency generator will be connected, e.g. through a transmission line, to a coil or an antenna depending on the selected frequency range.

The power generator may use an array of coils or antennas in order to concentrate the radiation on a distinct area of the implantable device. Arrays of coils or antennas can help in better compounding the electromagnetic field for regulatory requirements .

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention and their technical advantages may be better understood by referring to the following Figures:

Figure 1: Represents the scheme of the system. Susceptor coatings are placed in the external portion of an implantable device l.a); in this example a knee femur and hip prosthesis are coated with a susceptor layer. The system comprises: an electro-magnetic source apparatus l.b); a device to adjust power, freguency, waveform and delivery time l.c); a unit for the feedback of susceptor temperature l.d); the transmission line to a coil I.e) or an antenna system l.f).

Figure 2: View of a lower limb prosthetic device, on the left side an enlarged portion of a metallic stem 2. a) in which is displayed the dielectric layer 2.b), the thin film made in bio-compatible conductive material, with a thickness in the range of micro-nanometers 2.c) and the optional protective layer 2.d).

On the right side of the drawing is displayed a detail of part of a prosthetic device 2.e) where, due to morphological features of the implant, the susceptor material is present in the form of ferromagnetic/super-paramagnetic nano-particles scattered in a dielectric cement layer surrounding the prosthetic device 2.f) .

In the lower portion of figure 2) is displayed the cement compound 2.g) loaded with ferromagnetic/super-paramagnetic nano-particles used for the junction of the prosthesis to the bone. Dots in the compound area in the scheme represent nanoparticles scattered in the cement at an appropriate concentration to achieve sufficient heating for sterilization or treatment/prevention of infection.

Figure 3: Prosthetic device. On the right is shown an enlarged region where the coating susceptor thin film displays the superficial pattern 3.a) characterized by the fact of being forged with a specific thickness or texture, determined in such a way as to obtain a homogeneous coating surface temperature .

Fig. 3.b) shows a section view of the same area as in 3.a) (enlarged view), where it is possible to see the susceptor thin film Fig. 3.c), the dielectric layer beneath Fig. 3.d) and the prosthetic conductive material Fig. 3.e).

Figure 4 shows different coils / antenna systems connected to AC/RF/MW generators, spatially placed/oriented in order to convey energy to susceptors set on an implanted prosthesis / cement Fig. 4. a) .

The drawing shows: Fig. 4.b) a single inductive coil surrounding the implanted prosthetic device with susceptors, which is suitable for use with low frequencies (AC, kHz range) . For higher frequencies it is possible to use a wide range of antennas. For example, but without limitation, we can quote: horns, helix antennas, patch antennas, etc. as a single unit or in an array. In Fig. 4.c) is shown a horn antenna; a helix antenna in Fig. 4.d); an array configuration of antennas in Fig. 4.e; in Fig. 4.f) is shown an endoscopic antenna which makes it possible to reach directly the susceptor layer and emit a very directional MW beam which is capable of concentrating energy on a limited portion of the prosthetic device .

Fig 5 shows, by way of example, a hip prosthesis composed of 4 assemblable parts: cup, acetabular insert, ball-head and stem.

Two parts for which a replacement in the course of time is not generally foreseen because they are not subjected to wear are the stem 5.a) and the acetabular cup Fig. 5.d) . These may be based, for example, on a structure in titanium that is coated with a dielectric layer of polyethylene, ceramic or other dielectric prosthetic material Fig. 5.e), on the surface of which is added a conductive layer of calibrated thickness that varies between 20 nanometers and 20 micron so as to act as a susceptor layer or film Fig. 5.f) . The susceptor can in turn be coated with a protective dielectric layer indicated in Fig. 5.g) and in particular the selfsame susceptor, where it is made in titanium, can in turn be subjected to anodic oxidization treatment so creating a protective layer of oxidization on the surface of about 0.5-1 micron (Fig. 5.g). The invention contemplates the use of a cement compound to fix in place the implantable or prosthetic devices, which cement comprises nano particle susceptors Fig. 5.i). The nanoparticles are typically dispersed within the cement. Using this cement compound it is not necessary to create particular micro or nano surface coarseness on the prosthetic surfaces that have to be inserted in bones so as to promote direct osteointegration. Such coarse surfaces are particularly prone to bacterial colonization and infection.

The acetabular insert indicated in Fig. 5.c) and the head shown in Fig. 5.b) can be made e.g. in metal or ceramic, polyethylene or other dielectric prosthetic material, made in such a way as to have suitable mechanical properties so as to tolerate inevitable wear due to friction. In cases where there are parts in ceramic or polyethylene we can opt directly for the doping of the more superficial layer of the material with nano particle susceptors at a suitable concentration Fig 5.h) so as to obtain the desired increase in temperature when energy is supplied by AC/RF/MW generator.

Should one opt to make one of the parts indicated in 5.b) and

5.c) in metal, this same covered by dielectric will host on its surface the conductive susceptor layer thin film similarly to what is done for the stem. Where there is no wear due to friction between parts the susceptor layer will be able to perform its thermal functions whilst the areas subjected to wear will not by definition be in a position to host the biofilm because this will be continually removed by said friction. Parts b) and c), subjected among other things to partial wear of the susceptor layer whether this is a thin film or a dielectric stratum comprising nano-particles, are the only ones which are generally foreseen to need replacement.

Claims

CLAIM 1: Prosthetic or implantable device comprising a susceptor .
CLAIM 2: The prosthetic or implantable device of claim 1, wherein the susceptor comprises a layer of micro or nanometric thickness which coats the device.
CLAIM 3: The prosthetic or implantable device of claim 2, wherein the susceptor layer is separated from the surface of the device by a dielectric layer.
CLAIM 4: The prosthetic or implantable device of claim 2 or claim 3 wherein the layer has a variable thickness and /or is discontinuous .
CLAIM 5: The prosthetic or implantable device of any preceding claim, wherein the susceptor comprises ferromagnetic or superparamagnetic nano-particles.
CLAIM 6: The prosthetic or implantable device of any preceding claim, further comprising a protective layer on the external surface of the susceptor.
CLAIM 7: The prosthetic or implantable device of claim 6 in which the protective layer is an oxidized layer formed by anodic oxidation, optionally with a thickness of 0.5 to 1 micron.
CLAIM 8: The prosthetic or implantable device of any preceding claim, wherein the susceptor material is embedded in a threelayer structure, the internal layer (proximal to the prosthetic or implantable device) being a dielectric layer having the function of dielectric insulation with respect to the prosthetic device, and the external layer (distal from the prosthetic or implantable device) having the function of mechanical protection of the susceptor material from the external biological environment.
CLAIM 9: The implantable device of any preceding claim, wherein the device comprises or consists of a bone screw, one or more bone plates and/or spine components.
CLAIM 10: Biocompatible cement comprising ferromagnetic or super-paramagnetic nano-particle susceptors dispersed in the cement.

CLAIM 11: The prosthetic or implantable device of claim any of claims 1 to 9, or the bio compatible cement of claim 10, wherein the susceptor material is a conductor selected from

the group consisting of:

a) metals, for example titanium;

b) metal alloys, for example stainless steel, Cobalt Chromium Alloys or TI6A14V;

c) graphite;

d) carbon; or

e) pyrocarbon.
CLAIM 12: Power generator for use with the prosthetic or implantable device of any of claims 1 to 9 or 11, or the biocompatible cement of claim 10 or claim 11, which can deliver variable frequencies in the range AC (range of kHz), RF (range of MHz), and / or MW (range of GHz), and capable of variable power emission, the generator being connected to a coil or an antenna system that is able to concentrate, through the body, the emitted radiation on all or part of the susceptor comprised in the device or cement.
CLAIM 13: A method of sterilizing a prosthetic or implantable device according to any of claims 1 to 9 or 11, and/or a biocompatible cement according to claim 10 or claim 11, comprising subjecting the susceptor comprised in the device or cement to a variable electromagnetic field.
CLAIM 14: A method of treating infection of a prosthetic or implantable device according to any of claims 1 to 9 or 11, and/or a biocompatible cement according to claim 10 or claim 11, comprising subjecting the susceptor comprised in the device or cement to a variable electromagnetic field.
CLAIM 15: A susceptor material for use in treating or preventing infection of a prosthetic or implantable device according to any of claims 1 to 9 or 11, and/or a biocompatible cement according to claim 10 or claim 11, wherein the susceptor material is comprised within the device and/or cement.
CLAIM 16: The method of claim 14 or the susceptor material for use according to claim 15, wherein the infection is bacterial infection.

Intellectual

Property

Office

Application No: GB1617750.3 Examiner: Mr David Kirwin