WO2014045312A1

WO2014045312A1 - Prosthetic device capable of infection and pain control

Info

Publication number: WO2014045312A1
Application number: PCT/IT2013/000253
Authority: WO
Inventors: Fabio MASTANTUONO; Giacomo MASTANTUONO
Original assignee: Mastantuono Fabio; Mastantuono Giacomo
Priority date: 2012-09-20
Filing date: 2013-09-19
Publication date: 2014-03-27
Also published as: ITRM20120450A1

Abstract

A prosthesis or implantable device on the inside of the human body that can be active in preventing and/or contrasting infections and pain induced by possible infections through energy transfer from the outside allowing to generate heat on the surface of the prosthesis itself or directly on the surrounding biological material with the effect of sterilizing the bacterial bio-film grown on the prosthesis and the biological material immediately surrounding the prosthesis itself. In particular the prosthesis or implantable device carries out separately or simultaneously the following effects: a) Emitting continuous or pulsed radio frequencies capable of heating the bio-film and the surrounding tissues b) Being heated itself on the surface applying energy in the form of focused ultrasound on the external coating. c) Receiving thermal energy through a laser light conveyed to the prosthesis through optical fibers inserted in specific cylindrical cavities on the inside of the prosthesis reached by the optic fiber through a percutaneous approach. d) Containing electrical resistances allocated near the superficial layer of the prosthesis that can be activated through electrodes placed on the surface of the prosthesis itself, reached by percutaneous needle electrodes.

Description

PROSTHETIC DEVICE CAPABLE OF INFECTION AND PAIN CONTROL This invention concerns a new type of prosthesis device, either orthopedic or with other functions, that can be implanted in a human or animal body.

This device is capable of avoiding, reducing or controlling infections and or pain, which may occur or develop on the prosthesis itself, in its proximity its surface or inside, in a significant way, due to its innovative characteristics other from primary function it is implanted for.

For its peculiar characteristic the prosthesis is able to convey on the surrounding biological tissues energy under form of continuous or pulsed radio frequencies or heat inducing the typical effects of these energetic forms, both disinfectant and analgesic.

State of the art and quotations

The infection of prosthesis or devices implanted in the human body it 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 re-implantation or in presence of risk factors like a previous surgery, local hematoma, recurring infective illness or generalized bone illness, depressed immune system etc.. Implant or implantable device infections are usually classified on the basis of kind and time of infection:

In particular scientific literature distinguishes between:

POST SURGICAL INFECTION, originated at the moment of surgery, that becomes symptomatic in the very early postsurgical period. Diagnosis is generally made based on the medical history and the physical examination. Signs of systemic infection cud be present and generally the patient feels a continuous pain. These infections are caused by infected hematomas, the wound infections shift to the peri-prosthetic area.

CRONICAL INFECTIONS: this kind of infections is presumed to be originated at the time of surgery but the detection of the symptoms is delayed. The patient becomes aware of the presence of infections generally between six months and two years after surgery.

This kind of infections is associated to the deterioration of functionality and a growing pain.

The pain is often present at the time of surgery; it might occur either when the patient is in activity or when is at rest.

The early detachment of prosthetics components often is the only sign of the infection, this clue is not specific and it is similar to the aseptic detachment of the prosthesis.

TYPE III INFECTION also said hematogenous infections: it generally occurs two or more years after surgery. Dental manipulations, infections of urinary system or other remote infections could be the trigger.

Streptococcus is frequently isolated in this type of infection compared to other microorganisms. Generally a fever occurs in association with a 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 bacteremia episodes.

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

Te bio-film it is generally made of sessile bacteria. As soon as the bacteria colonies develop, sessile bacteria dethatch from the bio-film and spread out in the form of planktonic bacteria capable of scattering and colonizing the near areas. The bio-film generally grows slowly and the bio-film itself it is able to protect bacteria making them lowly sensitive to anti-microbic agents. THERAPY APPLIED TO DATE

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

In order to get rid of sessile bacteria the implant removal 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 the two forms: 1 Re- implant in two stages (temporary antibiotic spacer ) 2 implant in one stage (immediate implant substitution).

In case of infections at the early stage it is possible to try to save prosthetic device through deep surgical cleaning and an antibiotic extended therapy. Infection, once more frequent is nowadays rarer event due to appropriate environmental prophylaxis and due to the use of effective antibiotic prophylaxis.

Technical problem to be solved

The two problems in the prosthetic field that this invention aims to solve it is to succeed in preventing, removing or controlling infections which may occur on the prosthesis or in its proximity following the implant and the reduction of pain generated in this case from the implanted prosthetic device.

The solution it is reached inserting a prosthesis built in a way to convey the energy supplied to the prosthesis itself from the outside of the human body to the biological tissues situated near the prosthesis in a calibrated way. The energy conveyed is electromagnetic energy in form of continuous or pulsed radio frequencies in the range of 300-500 khz and or thermal energy directly through the surface of the prosthesis to the prosthetic bio-film or to sessile bacteria that are growing.

Through a calibrated increase in the bio-film temperature and of tissues in the immediate proximity to the prosthesis it is possible to obtain a reduction or a complete removal of the infection.

Radio frequencies in pulsed form conveyed through the prosthesis to the surrounding nerve endings deploy typical analgesic effects well known in scientific literature.

Divulgation of the invention

The prosthesis is provided with features that allow it to receive energy from the outside and convey it to the surrounding tissue in a calibrated way.

The invention consist in making the implantable device i.e. knee prosthesis, hip prosthesis, elbow prosthesis penis erectile device, etc, active being capable of emitting calibrated energy under the form of radio frequency and heat through its surface to the surrounding tissues.

The prosthesis shape and its mechanical qualities will be the ones of the anatomic portion that the prosthesis is meant to substitute or support, or in the case of a screw, or other supporting contrivance, the one suitable to the function that has to be achieved i. e. connecting two bones.

1. Some electrodes placed on the prosthesis that can receive the radio frequencies, or in addition or in substitution, one or more coils situated on the inside, will be present as a typical characteristic of the invention. The electrodes or the heads or the coils wires will be electrically connected through conductors to the prosthesis surface on the potions of prosthesis which will have to emit the receive radio frequency.

The prosthesis will have to be constructed placing electrodes on the external surface of the prosthetic device.

These will have to be adequate to connect themselves to electrode needles with a conductive tip which are put in touch with the electrodes on the surface of the prosthesis once inserted through the skin and the muscular tissues in a similar way to what is done when performing ad intramuscular injection. 2. If the external surface of the prosthesis is rather big it will have to be electrically segmented so to activate different portions separately or together through separate electrodes i.e. activating nearby portions. This may be accomplished with different building options. For example creating island shaped inserts on the structural body of the prosthesis in electrically end thermally insulated material, i.e. ceramic, polyethylene material etc. on which another conductive material amongst those most commonly used for ordinary prosthesis is collocated i. e. pure metal or steel alloys, titanium, graphite, carbon, pyrocarbon, cobalt-chromium alloys, etc.

The prosthesis therefore will contain electrodes or induction coils electrically connected to the conductive islands allocated on the surface of the prosthesis itself.

A characteristic element of the invention is that through the chosen building options the emitting capability of radiofrequencies applied to electrodes or inducted on the coils is obtained. A possibility in building it is obtained through coating of prosthesis with polyethylene or other suitable polymers and the making of conductive islands through polyethylene doping with graphite or other suitable conductive material.

3. Another element of an implemented version of a prosthesis with more compartments is the placing of a sequencing microchip, that is able to transfer the externally conveyed radio frequency energy in sequential way to the different separated superficial conductive island shaped portions, when the microchip is properly connected to the different conductive islands trough conductors.

4. A variant of the invention takes in to account that the prosthetic device might be heated in its superficial portion generating the results of a direct transfer of heat to surrounding biological material.

In this other version the prosthesis is built coating the surface of graphite or carbon or compounds or alloys able to acquire thermal energy when exposed to a focused ultrasound beam that causes an increase in superficial temperature, activating the release of thermal energy to the surrounding tissues.

The coating can be continuous or composed of more contiguous elements. The device for the application of focused ultrasound is the same or similar to the ones already existent and currently used for the thermo ablation of tumors or other biological tissues where power, time of exposition to the beam is properly set.

This variant can be obtained on it's own or integrated along with the technologies that use the radio frequencies abovementioned.

Advantages of the invention

The advantages obtained through the use of the active prosthesis, object of the invention, is a non pharmacologic control of infections or pain that may occur after a prosthetic surgery.

Description of at least one way of making the invention

A constructive example, that is not restrictive, in order to explain at least one way in which the prosthesis can be built is that of the hip prosthesis.

The prosthesis is made of a stem in titanium alloy that is appropriate to be inserted in the femoral canal, the potion that sticks out from the canal is coated up to the collar by a layer of polyethylene or an equivalent polymer whose exposed external surface it is divided in small strips around 3 mm thick, made conductive through doping with graphite (up to around 50%). The polymer that it is not subjected to doping between each stripe behaves like a pure insulator about one mm thick.

Each strip has got an electrode that is suitable to be reached through contact from the needle probe used to convey the radio frequencies from outside through a percutaneous approach. An isolated conductor is associated to each electrode on the strip, also this conductor can be reached through a needle probe that becoming a thermocouple allows to detect the superficial temperatures of biological tissues surrounding the prosthesis.

The prosthesis is crossed in its body by small channels of around a 20 gauge diameter that can be accessible from the outside through small funnel-shaped openings allocated on the surface of the prosthesis itself where through a needle probe an optical fiber can be inserted.

The channels cross the stem both ways allowing an optical fiber, once inserted from outside always percutaneously with a 20 gauge needle that behaves as a positioning case, to penetrate in to the prosthesis reaching the different portions of the prosthesis itself until it reaches the spherical titanium (or other appropriate material ) head that composes the femoral prosthesis. Also the acetabulum is provided with a cylindrical cavity of about 20 gouge diameter that develops in a spiral on the inside of the hemisphere, allowing the optical fiber to reach the different portions of the prosthesis when inserted in the prosthesis itself through a specific funnel shaped opening. The optical fiber can convey thermal energy to the different potions of the prosthesis through the use of a de-focalized surgical laser conveyed on the optical fiber so to allow to transfer in a calibrated way adequate temperature to the prosthetic portions in order to sterilize the bacterial film on the surface of the prosthesis itself avoiding excessive and irreparable damages to the healthy external surrounding tissues.

The critical areas of the prosthesis that for various reasons may not be receptive to the RF heating method (e.i. are not in contact with a biological tissues that can be heated with radio frequencies) are supported by the presence of electrical resistances connected to electrodes that may be reached by needle probe electrodes in order to reach the therapeutic temperature.

In another constructive version the prosthesis with the characteristics stated in the claims of the present patent contemplates that all or part of the prosthetic surface is coated with a continuous or fractionated layer of carbon. This material where in time a bio-film will deposit and become infected can be heated through the application from the outside of a focused ultrasound beam. The controlled increase in temperature that is generated on the carbon layer is capable of removing the bacterial infection in the bio-film.

Claims

1) An implant or implantable device within the human body forged in different shapes according to the biological parts it goes to substitute or support: hip, knee, wrist, shoulder or other anatomic portions usually implanted, characterized that by effect of its construction characteristics it is able to induce thermal energy on the biological material surrounding the implant through the use of radiofrequencies, focalized ultrasounds, laser light and/or electrical resistors.

2) An implant or implantable device within the human body, as according to the previous claim, constituted by one or more conducting bodies separated and isolated from each other through the use of interposed insulators, with electrodes connected to the same conducting bodies and reachable from the outside of the human body through a percutaneous approach entailing needle electrodes aimed to transfer, from the outside of the human body, on the various portions of the implant, energy in the form of continuous or pulsating radiofrequencies in the range of 300-500 kHz.

3) An implant or implantable device within the human body, as according to the previous claim, coated on the outer surface by an insulating material on which, through material doping, some separated conductive areas are created, with electrodes reachable from the outside of the human body through a percutaneous approach entailing needle electrodes aimed to transfer, from the outside of the human body, on the various conductive areas created on the surface of the implant, energy in the form of continuous or pulsating radiofrequencies in the range of 300-500 kHz.

4) An implant or implantable device, as according to the previous claim, characterized by the fact it contains a microchip placed within it and connected by conductors at the different points of the implant itself and to electrodes placed on the surface of the implant reachable by needle electrodes for the purpose of receiving radiofrequencies and supply tension; the microchip is programmed to carry out an automatic sequencing of the radiofrequency emissions on behalf of the various contiguous portions of the implant.

5) An implant or implantable device, as according to the previous claims, characterized by the fact that the various portions that make it up may be integrally coated or include inserts of carbon or graphite able to receive energy from the exterior when applied through the use of focalized ultrasounds causing an increase in surface temperature.

6) An implant or implantable device, as according to the previous claims, characterized by the fact of containing one or more induction coils inside the implant itself connected on behalf of conductors to the various portions of the implant aiming to transfer radiofrequencies on the surface of the implant without requiring needle electrodes connected from the exterior, the induction coils receive energy via radiofrequencies emitted by an electromagnetic field generator placed in the vicinity of the implant.

7) An implant or implantable device, as according to the previous claims, characterized by the fact of being equipped with temperature sensors on the surface of the implant; the collected data is then transmitted to the exterior of the human body either through RFID placed within the implant and connected to the sensors or through electrodes placed on the surface of the implant connected to the sensors and reachable from the outside of the human body through a percutaneous approach entailing needle electrodes.

8) An implant or implantable device, as according to the previous claims, characterized by the fact of having some cylindrical cuniculus within the material with a thickness of 20 gauge or less which allow the insertion and sliding of an optical fiber inserted in the opening of the cylindrical cuniculus on the surface of the implant through the use of an ordinary infiltration needle which serves as a case within which the fiber can slide, the above mentioned fiber optic inserted with the needle through percutaneous approach slides within the implant and can reach every point of the cuniculus and is connected on the opposite end to a de-focalized surgical laser enabling its beam to reach and heat up the portion of the implant at the necessary temperature (40-80 degrees centigrade) aiming to disinfect the implant by inerting the bacteria present in the biofilm formed on the implant itself and on the surrounding biological material.

9) An implant or implantable device within the human body, as according to the previous claim, characterized by the fact of having within the body of the implant itself some electrical resistors connected to electrodes placed on the surface of the implant reachable from the outside of the human body through a percutaneous approach entailing needle electrodes aimed to supply the resistance causing a controlled temperature increase of the surface of the implant itself.