Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/72—Intramedullary devices, e.g. pins or nails
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/326—Applying electric currents by contact electrodes alternating or intermittent currents for promoting growth of cells, e.g. bone cells
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/40—Applying electric fields by inductive or capacitive coupling ; Applying radio-frequency signals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N2/00—Magnetotherapy
  • A61N2/02—Magnetotherapy using magnetic fields produced by coils, including single turn loops or electromagnets
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N2/00—Magnetotherapy
  • A61N2/06—Magnetotherapy using magnetic fields produced by permanent magnets

Definitions

• the invention relates to an intramedullary nail system with an elongated, hollow, at least partially electrically conductive nail body, a coil arrangement, a first electrode connected to a first pole of the coil arrangement and a second electrode connected to a second pole of the coil arrangement.
• osteosynthesis serves for the load-stable fixation of the fragments of a broken or diseased bone in its uninjured, natural form by implanted screws, support plates, wires, bone marrow nails and the like, which are generally made of rustproof steel or titanium alloys.
• These osteosynthesis agents enable the patient to be mobilized quickly while immobilizing the damaged bone, which is an essential prerequisite for his healing.
• MRSA multi-resistant Staphylococcus aureus
• the transmission technology works according to the transformer principle: the injured or diseased body region is exposed to an extremely low-frequency sinusoidal magnetic field with a frequency of approx. 1 to 100 Hz - preferably 4 to 20 Hz - and a magnetic flux density of 0.5 to 5 mT (5 to 50 Gauss), which is generated by a functional current generator in one or more - primary - external current coils into which the body part provided with the osteosynthesis agents is introduced.
• These extremely low frequency electromagnetic see fields penetrate the tissue largely without loss, including any clothing and a plaster cast, as well as the non-magnetic (austenitic) supporting metals of the osteosynthesis.
• a - secondary - coil arrangement the so-called transmitter, is implanted.
• the electropotentials induced in the transmitter are thus brought into effect in the area of the bone lesion and in general in the tissue adjacent to the osteosynthesis means.
• the object of the invention is to improve a generic intramedullary nail system, in particular with regard to its manageability and flexible usability during the operation, its stability, its biological effect, its therapeutic effectiveness and its economy.
• the invention builds on the generic intramedullary nail system in that the coil arrangement is in a proximal end cap arrangement detachably connected to the nail body with an at least partially electrically conductive outer contact surface is provided, that the contact surface is electrically insulated from the nail body, that at least a portion of the contact surface forms the first electrode and that at least a portion of the nail body is the second electrode forms.
• the transmitter is arranged within the nail body cavity
• the present invention chooses a different arrangement, namely in a housing of an end cap, which is finally connected to the nail body during implantation. As a result, the nail body can be implanted unaffected by the electrical components.
• the use of a guide skewer is not hindered or even made impossible by components arranged in the nail body cavity.
• the guide rod is inserted into the broken bone, such as the tibia, in a conventional manner, and the intramedullary nail can be easily adjusted.
• the guide spit is then removed and distal and / or proximal locking screws can be applied, which penetrate the nail through opposite openings to achieve additional rotational stability.
• the end cap whose housing contacts a pole of the coil arrangement, is connected to the nail body. In particular, an electrical contact is established between the other pole of the coil arrangement and the nail body, so that the contact surface of the end cap arrangement and the nail body form a pair of electrodes.
• the nail body is not weakened by any recesses for receiving electrical components, for example millings.
• the nail body retains the stability that it would have in the conventional "non-electrical" case, which leads to a considerable reduction in the likelihood of nail breakage. This reduction is further increased by the fact that the healing process is shortened due to the advantageous effect of the electrical potentials.
• the end cap thus has a double function. On the one hand, it prevents connective tissue and bone from growing into the nail body, which would make explantation of the nail body more difficult.
• the end cap houses the components that impart the electrical properties to the intramedullary nail system.
• the end cap arrangement has an electrically conductive end cap housing, the surface of which forms the contact surface.
• the end cap houses are made of the same material as the nail body.
• the electrical components arranged in the end cap housing are preferably surrounded by a castable, electrically insulating plastic, for example epoxy resin.
• the proximal end of the end cap housing can be closed by an electrically conductive or insulating cover. It is not necessary to realize the entire surface of the electrically conductive end cap housing as an electrode.
• a ring electrode surrounding the cylinder jacket can be provided, for example, which is connected via an insulating layer to the part of the end cap housing which does not act as an electrode.
• the ring electrode can be embedded in the end cap housing, so that a smooth outer surface is provided.
• End cap assembly and the nail body are connected by means of an insulating layer via thread.
• the end cap including its threaded area, can thus be made of a uniform electrically conductive material, which simplifies production and ensures a stable connection between the nail body and the end cap through the use of metal threads.
• the required insulation between the end cap and the nail body is provided by an insulating layer, which is either firmly connected to the nail body or firmly to the end cap. It is also possible to insert the insulating layer as a separate element before putting on the end cap. While not taking advantage of an end cap made of a uniform material, it is also possible to remove the thread bearing cut the end cap to make it from an insulating material.
• the end cap arrangement has an electrically insulating end cap housing and an electrically conductive cover which closes the end cap housing and the surface of which forms the contact surface.
• the material for the end cap housing is, for example, polyethylene, for example of the type that is also used for acetabular cups in the field of endoprosthetics.
• the invention is developed in a particularly advantageous manner in that the second pole of the coil is connected via an elastic electrical contact to an electrically conductive insert element which is arranged in the cavity of the nail body and is electrically conductively connected to the nail body. Good electrical conductivity in the contact area is ensured by the elastic electrical contact via, for example, a spiral spring, a leaf spring or the like.
• an electrically conductive insert element is inserted into the nail body.
• the end cap is then screwed on, and the second pole of the coil arrangement is brought into contact with the nail body by an elastic electrical contact, which is preferably arranged centrally at the distal end of the end cap.
• the insert body is fastened in the nail body in such a way that at least one axial displacement in the distal direction is impeded.
• the insert body offers the necessary counterforce for the deformation of the elastic contact which favors the electrical contacting.
• the insert element is a compression screw, via which an axially directed force can be applied to a shaft screw penetrating two opposite elongated holes in the nail body.
• the compression screw presses against a shaft screw placed in the elongated holes, whereby the bone fragments are pressed against each other in the area of the fracture gap. In axially stable fractures, this creates a biomechanically favorable, active, circumferential compression of the fracture fragments.
• the compression screw has a dual function.
• the compression screw becomes a component of the electrical system, namely by establishing the contact between the second pole of the coil arrangement and the nail body acting as an electrode.
• the invention is developed in a particularly advantageous manner in that the coil arrangement is connected to the contact surface via an electrical rectifier in such a way that the first electrode formed by the contact surface has at least predominantly positive polarity.
• the magnetically induced osteogenesis is concentrated on the stabilization area of the intramedullary nail system, that is to say the nail body, since the osteogenesis depends on the polarity of the respective electrodes, namely on the cathode and is favored on the anode.
• bone formation in the vicinity of the end cap is hindered, avoided, and / or osteolysis is effected, while bone formation in the region of the fracture is desirably increased.
• an ohmic resistor is provided in parallel with the rectifier. It can also be provided that a capacitive resistor is provided in parallel with the rectifier.
• the coil arrangement has a coil core.
• a core for example a soft magnetic ferrite core
• the electrical power can be increased for a given external magnetic field strength. While maintaining the electrical power, lower magnetic field strengths and / or smaller components in the end cap can be used.
• At least one elongated soft magnetic element is inserted into the nail body.
• the arrangement of soft magnetic material in the nail body strengthens the magnetic field applied from the outside. This reinforcement also affects enough of the end cap, so that for a given transformer size higher electrical powers are available. For a given alternating magnetic field, a desired electrical power can thus be made available using a smaller transformer, so that less installation space is required for the transformer.
• the intramedullary nail system according to the invention can therefore be implemented with small end caps.
• At least one elongated, unsaturated permanent magnetic element is inserted into the nail body.
• the electrical fields generated via the surface electrodes on the nail body and on the end cap have only a very small depth of penetration into the surrounding tissue, which is usually only a few cell diameters.
• a magnetic field is also generated in tissue regions that are further away from the implant, and this decreases with increasing radial distance from the permanent magnetic element.
• the permanent magnetic element is magnetically unsaturated so that its magnetization can partially follow the alternating field applied from the outside. This ensures that there is no undesired complete concentration of the externally applied magnetic field on the area around the permanent magnetic element. Rather, a sufficient magnetic field can be provided in the area of the transmitter in the end cap.
• the unsaturated permanent magnetic element can thus advantageously be inserted in combination with a soft magnetic element.
• the at least one elongate element is surrounded by an insulating jacket.
• This can be formed, for example, by a shrink tube which envelops the element in a liquid-tight and gas-tight manner.
• elongated elements are surrounded by the same insulating jacket. If, for example, several soft magnetic elements are inserted or several unsaturated permanent magnetic elements or combinations thereof, these can immediately be combined in a single insulating jacket. The insertion is therefore accomplished with a single movement during the operation.
• the invention is further developed in a particularly useful manner in that the outer surface of the nail body is at least partially provided with an electrically conductive coating which enlarges the surface of the nail body and avoids the accumulation of bacteria.
• Bactericidal coatings are known. If you choose an electrically conductive bactericidal coating that enlarges the surface of the nail body, the bactericidal effect is enhanced, namely because of the enlarged surface for the transmission of the electric field to the surrounding tissue.
• the coating has silver.
• a silver coating can, for example, They can be applied directly to implants made of steel or titanium alloys using a sputtering technique.
• porous intermediate layer between the surface of the nail body and the coating.
• the electrically conductive connection of the coating with the surface of the nail body lying under the intermediate layer is provided by the surrounding body fluid and / or by direct contact of the silver particles with the surface.
• the porous intermediate layer consists for example of ceramic or plastic.
• the invention further relates to a nail body which is suitable for being used together with an intramedullary nail system according to the invention.
• the invention further relates to an end cap arrangement which is suitable for being used together with the intramedullary nail system according to the invention.
• Figure 1 is a side view of an intramedullary system according to the invention.
• FIG. 2 shows a section in the axial direction through the proximal end region of a first embodiment of an intramedullary nail system according to the invention
• FIG. 3 shows a section in the axial direction through the proximal end region of a second embodiment of an intramedullary nail system according to the invention
• FIG. 4 shows a first embodiment of a rectifier circuit that can be used in connection with the invention
• FIG. 5 shows a second embodiment of a rectifier circuit that can be used in the context of the intramedullary nail system according to the invention
• FIG. 6 shows a radial section through a nail body of an intramedullary nail system according to the invention with magnetic rods and arranged therein
• FIG. 7 shows a section through the surface of a nail body of an intramedullary nail system according to the invention with a coating that enlarges the surface.
• FIG. 1 shows a side view of an intramedullary nail system according to the invention
• FIG. 2 shows a section in the axial direction through the proximal end region of a first embodiment of an intramedullary nail system according to the invention.
• An intramedullary nail system is shown for the stabilization and rest position of fragments of a broken bone, for example the tibia bone (tibia), of the thigh bone (femur) or the humerus (humerus).
• the intramedullary nail system comprises an approximately cylindrical nail body 12 and an essentially axially symmetrical end cap arrangement 20 which closes an opening of the nail body 12 at its proximal end 54.
• the nail body 12 also has an opening (not shown) at its distal end 56.
• the openings at the proximal end 54 and at the distal end 56 are connected to one another via a cavity 10 in the nail body 12.
• Locking openings 58, 60, 62, 64 are provided in the wall of the nail body, the locking openings 58, 60, 62, 64 shown diametrically opposite each other locking opening, not shown.
• One group of locking openings 58, 60 is arranged at distal end 56, while the other group of locking openings 62, 64 is provided at proximal end 54.
• Also provided at the proximal end 54 of the nail body 12 is a pair of diametrically opposed slots 32, 34.
• the intramedullary nail system shown in Figure 1 is used in the context of osteosynthesis as follows. First, a guide spike (not shown) is inserted into the cavity of a fractured long bone beyond the fracture gap. The nail body 12 is then guided over the guide spit into the long bones. The guide spit can be removed below. Via the locking openings 58, 60, 62, 64, one or more locking screws penetrating the bone shaft can be inserted, which give the bone stabilized by the nail body 12 additional rotational stability. Another shaft screw can be passed through the elongated holes 32.
• an end cap arrangement 20 is placed on the nail body 12, preferably via a threaded region 26, which is formed by an external thread on the end cap arrangement 20 in an internal thread of the nail body.
• the end cap arrangement 20 contains a coil arrangement 14, and when the end cap arrangement 20 is screwed on, the latter itself acts as an electrode, while the nail body 12 forms the counter electrode.
• the coil arrangement 14 is arranged in a free volume of the end cap housing 22.
• the coil arrangement 14 surrounds a soft iron core, which is provided to amplify the magnetic alternating field supplied from the outside.
• One pole of the coil arrangement 14 comes into contact with a contact point 76 of the end cap housing 22 via a parallel circuit composed of diode 36, ohmic resistor 42 and capacitive resistor 44.
• the rectifier circuit implemented by the diode 36 can have an advantageous effect on the localization of the bone growth.
• the surface of the end cap housing 22 becomes the anode, on which bone growth is inhibited or even osteolysis takes place, while the nail body 12 becomes the cathode, so that bone growth is promoted in particular in the fracture area.
• the components connected in parallel with the diode 36 that is to say the ohmic resistor 42 and the capacitive resistor 44, are optional. Through them the
• the end cap arrangement 20 is screwed into the nail body 12 via a threaded region 26, an insulating layer 24 preventing the short circuiting of the coil arrangement being provided.
• This insulating layer 24 advantageously continues in the proximal direction, for example up to the insulation 66 at the transition from the proximal to the distal region of the end cap arrangement 20.
• a compression screw 30 is also screwed into the nail body 12 via a threaded region 68. As mentioned, this compression screw 30 is used to apply force in the axial direction to a shaft screw penetrating the elongated holes 32, 34, so that compression can take place in the region of the fracture gap.
• the compression screw 30 also serves to make electrical contact with the spiral spring 28, which is supported at its proximal end on the insulation 24 and at its distal end on the compression screw 30.
• the electrical contact between the coil arrangement 14, that is to say in particular the contact point 74, and the nail body 12 is established via the threaded region 68 and optionally via the shaft screw, not shown, penetrating the elongated holes 32, 34.
• the electrical components inside the end cap housing 22 are of a biological type compatible epoxy cast resin compound electrically insulating and mechanically stabilizing.
• FIG. 3 shows a section in the axial direction through the proximal end region of a second embodiment of an intramedullary nail system according to the invention.
• an end cap housing 22 made of electrically insulating material, for example biologically compatible polyethylene, is used here.
• the contact surface is formed by an electrically conductive cover 90, which closes the end cap housing 22 at its proximal end.
• the lid 90 may be connected to the end cap housing by gluing, screwing, clipping or the like.
• the insulations 24, 26, 70 of the end cap housing 22 against the nail body described in connection with FIG. 2 are unnecessary in the case of an electrically insulating end cap housing 22 according to FIG. 3.
• FIGS. 4 and 5 show two embodiments of a rectifier circuit that can be used in connection with the invention.
• the circuit in FIG. 4 essentially corresponds to the circuit already described with reference to FIG. 2, although there is no capacitive resistance. Similarly, the parallel connection of an ohmic resistor 62 may be unnecessary depending on the application. While FIG. 4 shows a one-way rectifier circuit, FIG. 5 shows a two-way rectification.
• the coil arrangement 14 has a center tap 78 from which it connects via an ohmic resistor 82 to the contact point 74 is connected to the nail body 12 or the spiral spring 28 leading circuit node 80.
• the center tap 78 is also directly connected to the contact point 76 on the end cap housing.
• Two diodes 38, 40 are connected to the circuit node 80 and contact the two end points of the coil arrangement.
• the two-way rectifier circuit shown in FIG. 5 can also be modified by the resistances influencing the AC behavior of the circuit.
• FIG. 6 shows a radial section through a nail body of an intramedullary nail system according to the invention with magnetic rods arranged therein.
• the nail body 12 has several axially arranged along its circumference
• Recesses 84 which provide rotation stabilization of the nail body 12 in the bone.
• An insulating jacket 52 with four rods 48, 50 arranged therein is provided in the cavity 10 of the nail body 12.
• Other variants are possible, namely a variation in the number of rods, an exclusive provision of soft magnetic material or an exclusive provision of unsaturated permanent magnetic material.
• the soft-magnetic rods 48 bundle the alternating magnetic field supplied from the outside, so that local amplification occurs, which acts into the area of the coil arrangement 14 provided in the end cap arrangement 20.
• the soft magnetic rods 48 have a reinforcing effect on the electrical power provided by the tissue electrodes.
• the unsaturated permanent magnetic rod 50 can be fed to the externally supplied magnetic partially follow the alternating magnetic field so that, unlike with a saturated permanent magnetic rod, a "short circuit" of the magnetic field is prevented.
• the special effect of the permanent magnetic element comes into play in the absence of an external magnetic field, namely by providing a radially outwardly decreasing magnetic gradient field penetrating into the tissue area surrounding the nail body 12.
• electrical fields are induced in the tissue that promote the healing process.
• the permanent magnetic field penetrates deep into the tissue, so that electrical fields that promote the healing process are also induced here.
• An external alternating magnetic field can additionally set the permanent magnet in a vibration which has an advantageous effect on the healing process.
• FIG. 7 shows a section through the surface of a nail body of an intramedullary nail system according to the invention with a coating that enlarges the surface.
• the outer surface of the nail body 12 is provided with an electrically conductive coating which enlarges the surface and avoids the accumulation of bacteria, preferably of silver particles 26 present in a colloidal state.
• the coating of the surface is mediated by a porous intermediate layer 68, which consists for example of plastic or ceramic. It is also possible that the silver particles are additionally or alternatively embedded in the intermediate layer. This can be achieved by applying a ceramic-silver emulsion.
• the electrical contact between the surface of the nail body 12 and the electrically conductive coating 86 is made available via body fluid or by direct contact of the surface of the nail body 12 with the coating 86 in the region of the pores of the porous surface 88.
• the bactericidal coating 86 prevents the accumulation of bacteria even without electrical potentials being made available via the nail surface. In the context of the present invention, this effect is amplified by the induced electric fields. Furthermore, the effect of the induced electric field on the surrounding tissue is also favored, since the electrically conductive coating 86 increases the contact surface between the tissue and the electrode. As a result, the positive biological effects can be improved as a result, or simpler and smaller devices can be used while maintaining a given quality, in particular with regard to the coil arrangement and the devices which generate the external magnetic alternating field.
• end cap assembly 22 end cap housing 24 insulating layer

Landscapes

• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• General Health & Medical Sciences (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• Animal Behavior & Ethology (AREA)
• Radiology & Medical Imaging (AREA)
• Surgery (AREA)
• Molecular Biology (AREA)
• Medical Informatics (AREA)
• Heart & Thoracic Surgery (AREA)
• Cell Biology (AREA)
• Neurology (AREA)
• Surgical Instruments (AREA)
• Magnetic Treatment Devices (AREA)
• Electrotherapy Devices (AREA)
• Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38222709

Family Applications (1)

Country Status (10)

Families Citing this family (29)

Citations (5)

Family Cites Families (19)

• 2006
  • 2006-04-19 DE DE102006018191A patent/DE102006018191B4/de not_active Expired - Fee Related
• 2007
  • 2007-04-02 ES ES07006869T patent/ES2316112T3/es active Active
  • 2007-04-02 AT AT07006869T patent/ATE413847T1/de not_active IP Right Cessation
  • 2007-04-02 DE DE502007000228T patent/DE502007000228D1/de active Active
  • 2007-04-02 EP EP07006869A patent/EP1847227B1/de active Active
  • 2007-04-12 WO PCT/DE2007/000640 patent/WO2007118457A1/de not_active Ceased
  • 2007-04-12 CN CN2007800140096A patent/CN101431956B/zh not_active Expired - Fee Related
  • 2007-04-13 AU AU2007201642A patent/AU2007201642B2/en not_active Ceased
  • 2007-04-17 US US11/736,173 patent/US9439694B2/en not_active Expired - Fee Related
  • 2007-04-18 CA CA002585220A patent/CA2585220C/en not_active Expired - Fee Related
  • 2007-04-19 JP JP2007110806A patent/JP4162051B2/ja not_active Expired - Fee Related

Patent Citations (6)

Also Published As

Similar Documents

Legal Events