NO20200114A1

NO20200114A1 - A material for surgical use

Info

Publication number: NO20200114A1
Application number: NO20200114A
Authority: NO
Inventors: Emil Abry; Lasse Efskind
Original assignee: Emil Abry; Lasse Efskind
Priority date: 2020-01-29
Filing date: 2020-01-29
Publication date: 2021-07-30
Also published as: WO2021154089A1

Description

Technical Field

[0001] The present invention relates to materials, structures and methods used in traumatology. More particularly, the present invention relates to plates and screws for osteosynthesis, and materials that can be adjusted in the body by applying external energy such as electromagnetic energy.

Background Art

[0002] Plates, nails, and other structures of various materials are widely used around the world today in bone fracture surgery and healing. Typically, such internal fixation devices are inserted during a first surgery to maintain stability and alignment during the healing process of the fracture. As the fracture heals, a large proportion of these devices must be removed with a second surgery that poses undesirable risks and costs.

[0003] Additionally, the rigidity (stiffer than the bone) of many internal fixation devices may pose problems during healing. A frequent challenge is that fixation devices do not always align the bone properly thus requiring further surgery to correct alignment. Plates and screws may also cause soft tissue irritation or progressive foreign body reactions when kept in place for long periods of time after bone healing. Further, as one can experience with bone marrow nailing or cast treatment of fractures, it is not necessary to have absolute rigidity during fracture healing. Depending on whether good alignment and positioning are secured, healing can occur adequately with some movements or pulsations in the fracture zone during healing. There are two modes of fracture healing: (i) absolute rigidity and (ii) one allowing some movement with callus formation.

[0004] U.S. Pat. No.5,340,428 to Kodokian teaches a method for heating a composite comprising a nonconductive material that is a thermoplastic or a thermoset reinforced with conductive materials such as carbon fibers, by incorporating coupling particles in the structure. The structure is oriented in the plane of a magnetic field induced at frequencies from 3 kHz to 7 MHz, whereby the coupling particles respond as susceptors to the induced magnetic field and are preferentially heated (carbon fibers are not heated). However, this process is not meant to be used in vivo.

[0005] European Patent EP2654589 (B1) to Hulliger teaches a device for implanting heat deformable fixation elements of different sizes in a bone, comprises a hand piece extending from a proximal end to a distal end and including an internal optical waveguide connected to a laser source and open to the distal end of the hand piece and a light guiding tip extending from a proximal end to a distal end, the proximal end of the light guiding tip being removably mechanically and optically connectable to the distal end of the hand piece and the distal end of the light guiding tip being configured to permit removable attachment of a bone fixation element, the light guiding tip including an optical waveguide, wherein the light guiding tip is configured to control a total radiant energy Q transmitted from the laser source to the bone fixation element. This solution requires that the laser source is directly connected via cable to the bone fixation element with potential risk for infections.

[0006] Toshifumi Shimizu and Masaaki Matsui in “New magnetic implant material for interstitial hyperthermia”, Science and Technology of Advanced Materials 4 (2003) 469-473 teach the magnetic properties of ceramic particles that are at the same time biocompatible.

[0007] US Pat. No.20090265016 A1 to Efskind et al. teaches use of a material, structure, and method for surgical use in traumatology. More particularly, their invention relates to a composite material, a temporary biocompatible support structure, and related methods of use of the same in aiding osteosynthesis during healing of a bone fracture. The material keeps its strength in a solid phase in vivo and, to aid removal upon healing, can be transformed into a substantially fluid phase, including, for example, a pulverized state, by the application of energy at a chosen time. The patent focuses exclusively on the removal of the material and does not address the critical issues of re-aligning implants in vivo and changing shape of tips of surgical nails or screws to relieve pains of the patient.

[0008] Accordingly, there is a need for a material suitable for surgical use in the internal fixation of bone fractures that can be moulded and or bent in vivo for fast and easy realignment and in vivo correction during healing.

Brief summary of the invention

[0009] An at least partly ferromagnetic material for surgical use in bone fracture fixation used in biocompatible fastening means and support structures is disclosed.

[0010] An at least partly ferromagnetic material for surgical use in bone fracture fixation that may become mouldable and or bendable when heated in vivo with an external radiation source. This material can be made to change shape or orientation once heated by applying an external mechanical force such as bending or pressure.

[0011] The at least partly ferromagnetic material comprises in one embodiment a first component comprising a biocompatible polymer matrix, and at least a second component capable of strengthening the biocompatible polymer matrix and increasing energy absorbance. It may alternatively comprise a second component capable of strengthening the biocompatible polymer matrix and a third component capable of increasing energy absorbance.

[0012] A temporary biocompatible fastening means for aiding bone fracture osteosynthesis in a living organism may be made of the at least partly ferromagnetic material. The fastening means may be attached to a bone in a living organism. The fastening means is solid at body temperature of mammals and is mouldable and or bendable in vivo when heated by an external energy, such as induction heating, to a temperature above body temperature, but without damaging the surrounding tissues.

[0013] A temporary biocompatible support structure for aiding bone fracture osteosynthesis in a living organism may be made of the at least partly ferromagnetic material. The support structure is attached to a bone in a living organism. The support structure is solid at body temperature of a mammal. It is mouldable and or bendable and may be for instance bent in vivo when heated by an external energy, such as induction heating, to a temperature above body temperature, but without damaging the surrounding tissues.

Description of the drawings

[0014] Fig 1. Correction of wrong fracture angulation of volar plate in wrist

[0015] Fig 2. Collum or petrochanteric femur fracture or related fracture fixated by screws or gliding screw in plate. Head of screw can be shortened for pain relieve

[0016] Fig 3. Locking of screws on the opposite side of the plate

[0017] Fig 4. Correction of alignment of thin nails (TED) used for fixation of larger bones.

[0018] Fig 5. Avoiding penetration of screw fixation into joint by increasing screw diameter and reducing length of screw (shown here: proximal humerus and shoulder joint)

[0019] Fig 6. In-situ fixation screws with increasing diameter and shortened length

[0020] Fig 7. Avoiding penetration of screw fixation into joint by shortening the length with constant diameter (shown here: proximal humerus and shoulder joint)

[0021] Fig 8. In-situ fixation screws with constant diameter and shortened length

[0022] Fig 9. Avoiding penetration of screw fixation into joint by increasing diameter and keeping length constant (shown here: proximal humerus and shoulder joint)

[0023] Fig 10. In-situ fixation screws with increased diameter and constant length

Detailed description of the invention

[0024] The material and different embodiments of its use will be described in detail referring to the enclosed figures.

[0025] The embodiments of the present invention use an at least partly ferromagnetic material for surgical use in bone fracture fixation. This at least partly ferromagnetic material becomes mouldable when heated with an external radiation source at a chosen time and can be made to change shape once heated upon application of an external mechanical force. It becomes mouldable at temperatures above the body temperature of mammals without damaging the surrounding tissues. Examples for use of the material include, but are not limited to humans, horses, dogs and cats.

[0026] The radiation source may for instance be an alternating electromagnetic field such as an induction heating device.

[0027] In one embodiment, the at least partly ferromagnetic material is a magnetic material. In another embodiment, the at least partly ferromagnetic material comprises a first component comprising a biocompatible polymer matrix and at least a second component capable of strengthening the biocompatible polymer matrix and increasing energy absorbance.

[0028] In a further embodiment, the second component may strengthen the biocompatible polymer matrix and a third component may increase the energy absorbance. The second and or the third component may have the shape of a particle, flake or fibre.

[0029] At normal ambient pressure, the polymer matrix becomes mouldable when heated with an external radiation source to temperatures approximately greater than the viable range of normal core body temperatures of the subject organism, but less than a temperature substantially damaging the cells or body tissue, such as epithelium, connective tissue, muscle tissue, and nervous tissue, of the subject organism.

[0030] In a preferred embodiment, the polymer matrix has a melting point, melting phase, or melting range at a temperature or over a range of temperatures that is or are greater than about 37° C. and less than a temperature substantially damaging human body tissue. Most preferably, the polymer matrix has a melting point, melting phase, or melting range at a temperature substantially within a range of about 45° C. to about 50° C., inclusive.

[0031] The polymer matrix may include one or more polymers. Suitable polymers include, by way of example and not of limitation: (1) poly(propylene glycol)-blockpoly(ethylene glycol)-block-poly(propylene glycol)-bis(2-aminopropyl ether) (PPG-PEG-PPG); (2) poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (PEGMAGMA); (3) poly(ethylene adipate), tolylene 2,4-diisocyanate terminated (PEAcy); (4) poly(ethylene glycol) (PEG); (5) poly(ethylene glycol) dimethyl ether (PEGdme); (6) poly(ethylene glycol) distearate (PEGds); (7) poly(propylene carbonate) (PPC); (8) poly(ethylene oxide) (PEO); (9) poly(vinyl acetate) (PVAc).

[0032] Other suitable polymers for the polymer matrix include polycaprolactone (PCL) and polycaprolactone polyols.

[0033] The second component is added to the first component to strengthen the polymer matrix. In some embodiments, the second component includes particles, flakes, or fibres, such as, for example, clay, ceramics, metal flakes, carbon, mineral, or glass fibres.

[0034] Induction heating and electromagnetic radiation allow the heating of electrically conducting materials. Heat is generated by eddy currents. If the material is also ferromagnetic, heat may also be generated by magnetic hysteresis losses. Magnetic materials improve the induction heating process because of hysteresis losses.

[0035] Preferably, the second component of the composite material is also capable of absorbing energy such as electromagnetic radiation of an induction heating device. The second component may be capable of absorbing energy, such as electromagnetic radiation.

[0036] In some embodiments, a third component is added to the first component and the second component of the composite material to further strengthen the polymer matrix and/or to increase its ability to absorb energy. In some embodiments, the third component includes particles, flakes, or fibres, such as, for example, clay, ceramics, metal flakes, carbon, mineral, or glass fibres.

[0037] As with the second component, the third component may also be capable of absorbing energy, such as heat, via, for instance, electromagnetic radiation.

[0038] Other components, such as a fourth component, a fifth component, and so on, may also be added to strengthen the polymer matrix and/or absorb energy, or to impart any other of a number of desirable properties to the support structure. Alternatively, one or more of these components may be added to facilitate dispersion into the polymer matrix.

[0039] With the addition to the first component including the polymer matrix of the second component and, in some embodiments, a third or more components, the composite material comprising all two or more components has a strength, tensile strength, stiffness, and/or flexural strength in a substantially solid phase that is comparable to or better than commonly-used osteosynthesis materials, such as other metals or alloys commonly employed in orthopaedics, such as, for example, titanium and its alloys, stainless steel, and cobalt-chromium alloys. In other words, the composite material has strength sufficient to support a bone. The composite may be comparable to metal in strength but may have a physical flexibility closer to the flexibility of bone. This comparable strength or function is desirable so that the composite material can be an adequate substitute for metal as used in temporary fixation devices, such as osteosynthesis materials, and biocompatible support structures made and used in accordance with the present invention. The composite material is also resistant to fatigue and is biocompatible. An enhanced resistance to fatigue as compared to metal is desirable to improve the suitability of the composite material for osteosynthesis.

[0040] Referring to Fig 1. one embodiment of the invention may be used as a temporary biocompatible support structure for aiding bone fracture osteosynthesis in a living organism. The volar plate for wrists 0105 may comprise of the at least partly ferromagnetic material comprising in one embodiment a first component comprising a biocompatible polymer matrix, and a second component capable of strengthening said biocompatible polymer matrix and increasing energy absorbance or a second component capable of strengthening said biocompatible polymer matrix and a third component capable of increasing said energy absorbance.

[0041] The support structure 0105 is attached to a wrist 0102, that is fractured 0103 in a living organism 0101 using traditional fixing screws or nails 0104. In one embodiment, the support structure is made of at least partly ferromagnetic material where the polymer matrix comprises polycaprolactone and a polycaprolactone polyol.

[0042] The living organism may be a mammal or human being. The body temperature is a temperature within a range of approximately 34° C. to approximately 42° C.

[0043] Support structure 0104 becomes bendable upon applying an external energy 0106 that is heating the support structure to a temperature in excess of the body temperature. The shape and orientation of support structure may be altered by applying external bending moment 0107 to realign the fractured wrist in vivo and said support structure re-solidifies upon removal of external energy.

[0044] The process of correcting a wrong angulation of the support structure is accomplished without the need for an operation.

[0045] Fig 2. Shows a hip bone 0202, femur 0204 and a collum or petrochanteric femur fracture or related fracture 0203 fixated by screw or gliding screw 0205. Because of pressure the fracture will often compress and become shorter 0206, making the gliding screw end to penetrate laterally and induce pain and even penetrate the skin 0201. With induction heating 0207 one can digitally in situ compress 0208 the tip 0209 and hence avert the problem. There are similar challenges with screws in the ankle region.

[0046] The temporary biocompatible fastening means 0205 may be made of an at least partly ferromagnetic material. The at least partly ferromagnetic material comprises in one embodiment a first component comprising a biocompatible polymer matrix, and at least a second component capable of strengthening said biocompatible polymer matrix and increasing said energy absorbance.

Alternatively, a second component capable of strengthening said biocompatible polymer matrix and a third component capable of increasing energy absorbance.

[0047] The screw or sliding screw 0205, 0303, 0505, Fig 6, Fig 8 and Gig 10 may be made of sections or components of different materials. These sections or components may be joined by physical, mechanical or chemical forces, such as adhesive bonding.

[0048] A further embodiment is shown in Fig.3. For long bones, such as Femur or Humerus 0301, that are heavily loaded, it may be convenient to lock the screws 0307 on the opposite site of the plate 0304 to increase stability. This can be done without an extra incision 0302 by induction softening 0305 of the tip of the screws and applying external digital pressure 0306.

[0049] Yet another embodiment is shown in Fig.4. In children one uses thin nails (TED) 0404 for fixation in larger bones, for example femur 0403 (hip bone 0402; skin and muscle 0401). The alignment of the fracture 0405 is often not optimal.

The alignment can without reoperation be corrected by induction heating 0406 and then x-ray guided correction by bending 0407.

[0050] Fig 5 shows a further embodiment of the use of the fastening means, shown here is the proximal humerus and shoulder joint 0501. Especially in proximal humerus 0502 near the shoulder joint the bone is soft and fragile, and screw fixations may easily penetrate into the joint. A plate 0504, traditional fixation screws 0503 and fastening means 0505 may be used to fixate the bone fracture 0506. To avoid screws or fastening means from penetrating into the joint 0505 once the bone fracture is compressed 0507, the distal end of the fastening means is modified 0509 by induction heating 0508. This is may be done during the primary operation or later. The tip of the screw has an in-built tension mechanism that compresses the tip and makes it wider, like a small pillow 0611. This prevents further penetration. The bone matrix is usually soft enough to allow the tip of the screw to expand.

[0051] Fig 7 and 9 show more embodiments of the use of the fastening means. Here the fastening means have different mechanisms to change the shape of the distal end. 0701 shows an in-situ fixation screw with constant diameter and shortened length after heating while 0901 shows an in-situ fixation screw where the diameter increases while the screw remains at constant length.

[0052] Fig 6 shows an embodiment of the fastening means; shown as a fixation screw for the proximal humerus 0601 and shoulder joint 0602 for a shoulder 0603. Especially in proximal humerus near the shoulder joint the bone is known to be soft and fragile.0604 to 0609 show the fastening means as installed during the primary operation (0604 end support at outer tip of fixation screw; 0605 mouldable section of fixation screw, 0606 rod, 0607 cylindrical housing of the fixation screw, 0608 pretensioned spring, 0609 retaining disk). To protect the shoulder joint from fastening means protruding into the joint, the distal end of the fastening means is modified by induction heating 0610. The mouldable section 0605 may increase its diameter and shorten its length upon heating with an external radiation source. This is may be done during the primary operation or later. The pretensioned spring 0608 compresses the mouldable section 0605 and makes it wider, like a small pillow 0611. This prevents further penetration.

[0053] Fig 8 shows another embodiment of the fastening means; shown as a fixation screw for the proximal humerus 0801 and shoulder joint 0802 for a shoulder 0803. Especially in proximal humerus near the shoulder joint the bone is known to be soft and fragile.0804 to 0809 show the fastening means as installed during the primary operation (0804 end support at outer tip of fixation screw; 0805 hollow mouldable section of fixation screw, 0806 rod, 0807 cylindrical housing of the fixation screw, 0808 pretensioned spring, 0809 retaining disk). To protect the shoulder joint from fastening means protruding into the joint, the distal end of the fastening means is modified by induction heating 0810. The hollow mouldable section 0805 may shorten its length without increasing the diameter upon heating with an external radiation source. This is may be done during the primary operation or later. The pretensioned spring 0808 compresses the mouldable section 0805 and makes it short 0811 and retracts the fastening means from the joint. This prevents further penetration.

[0054] Fig 10 shows an embodiment of the fastening means; shown as a fixation screw for the proximal humerus 1001 and shoulder joint 1002 for a shoulder 1003. Especially in proximal humerus near the shoulder joint the bone is known to be soft and fragile.1004 to 1009 show the fastening means as installed during the primary operation (1004 end support at outer tip of fixation screw; 1005 mouldable section of fixation screw, 1006 rod, 1007 retaining disk, 1008 pretensioned spring, 0609 cylindrical housing of the fixation screw). To protect the shoulder joint from fastening means protruding into the joint, the distal end of the fastening means is modified by induction heating 1010. The mouldable section 1005 may increase its diameter without shortening its length upon heating with an external radiation source. This is may be done during the primary operation or later. The pretensioned spring 1008 compresses the mouldable section 1005 and makes it wider, like a small pillow 1011. This prevents further penetration.

[0055] A method for moulding and or bending temporary support structures and fastening means for aiding bone fracture osteosynthesis in a living organism may comprise the following steps: (i) identifying and selecting patients with bone fracture and who have received a biocompatible support structure or fastening means where a misalignment or a protrusion of screw is detected, (ii) applying an external energy to the outside of the fracture for a predetermined duration and intensity, (iii) performing the correction to either re-aligning by bending support structure or flattening protruding fastening means, and (iv) let support structure or fastening means cool down to regain strength.

Claims

Claims

[Claim 1] An at least partly ferromagnetic material for surgical use in bone fracture fixation comprising

an at least partly ferromagnetic material that becomes mouldable and or bendable when heated with an external radiation source

said material can be made to change shape once heated upon application of an external mechanical force
[Claim 2] The at least partly ferromagnetic material of claim 1, wherein the radiation source is an alternating electromagnetic field such as an induction heating device
[Claim 3] The at least partly ferromagnetic material of claim 1, becomes mouldable and or bendable at temperatures above the body temperature of mammals
[Claim 4] The at least partly ferromagnetic material of claim 1, wherein the at least partly ferromagnetic material in one embodiment comprises

a first component comprising a biocompatible polymer matrix

at least a second component capable of strengthening said biocompatible polymer matrix and increasing said energy absorbance

or a second component capable of strengthening said biocompatible polymer matrix and a third component capable of increasing said energy absorbance.

wherein said at least partly ferromagnetic material may become mouldable or bendable by absorbing energy at a chosen time.
[Claim 5] The at least partly ferromagnetic material of claim 4, wherein at least one of said second component and said third component comprise at least one of a particle, a flake or a fibre.
[Claim 6] The at least partly ferromagnetic material of claim 4, wherein said biocompatible polymer matrix comprises at least one of: (1) polycaprolactone and (2) a polycaprolactone polyol.
[Claim 7] A temporary biocompatible fastening means for aiding bone fracture osteosynthesis in a living organism comprising:

an at least partly ferromagnetic material

said at least partly ferromagnetic material comprises in one embodiment a first component comprising a biocompatible polymer matrix, and at least a second component capable of strengthening said biocompatible polymer matrix and increasing said energy absorbance

or a second component capable of strengthening said biocompatible polymer matrix and a third component capable of increasing said energy absorbance.

wherein said fastening means is attached to a bone in a living organism, wherein said fastening means is solid at a body temperature of said living organism and is mouldable and or bendable when heated to a temperature above said body temperature in vivo.
[Claim 8] The biocompatible fastening means of claim 7, wherein said fastening means may be made of sections or components of different materials
[Claim 9] The biocompatible fastening means of claim 7, wherein the sections or components are joined by physical, mechanical or chemical forces
[Claim 10] The biocompatible fastening means of claim 7, wherein said polymer matrix comprises at least one of: (1) polycaprolactone and (2) a polycaprolactone polyol.
[Claim 11] The biocompatible fastening means of claim 7, wherein the proximal end of said fastening means becomes mouldable upon applying an external energy and said mouldable proximal end of fastening means may be made to change shape by external pressure on body surface,
[Claim 12] The biocompatible fastening means of claim 7, wherein the distal end is subject to a mechanical force, the distal end may be heated by applying an external energy and the material of the distal end of the fastening means repositioned in the bone cavity, upon removal of external energy said fastening is supported again
[Claim 13] The biocompatible fastening means of claim 7, wherein said fastening means becomes bendable upon applying an external energy and said fastening means may be made to bend by external pressure or bending moment on body surface,
[Claim 14] The biocompatible fastening means of claim 13, wherein said fastening may be a marrow nail for fracture in long bones in children.
[Claim 15] A temporary biocompatible support structure for aiding bone fracture osteosynthesis in a living organism comprising:

an at least partly ferromagnetic material

said at least partly ferromagnetic material comprises in one embodiment a first component comprising a biocompatible polymer matrix, and at least a second component capable of strengthening said biocompatible polymer matrix and increasing said energy absorbance

or a second component capable of strengthening said biocompatible polymer matrix and a third component capable of increasing said energy absorbance.

wherein said support structure is attached to a bone in a living organism, wherein said support structure is solid at a body temperature of said living organism and is mouldable and or bendable when heated to a temperature above said body temperature in vivo.
[Claim 16] The support structure of claim 15, wherein said living organism is a mammal and said body temperature is a temperature within a range of approximately 34° C. to approximately 42° C.
[Claim 17] The support structure of claim 16, wherein said mammal is a human.
[Claim 18] The support structure of claim 15, wherein said polymer matrix comprises at least one of: (1) polycaprolactone and (2) a polycaprolactone polyol.
[Claim 19] The support structure of claim 15, wherein said support structure upon applying an external energy becomes mouldable and or bendable, and the shape and orientation of said support structure may be altered by applying an external bending moment to realign the fractur surface in vivo.
[Claim 20] A method for moulding and or bending a temporary support structures and fastening means for aiding bone fracture osteosynthesis in a living organism comprising the following steps

- identifying and selecting patients with bone fracture and who have received a biocompatible support structure or fastening means where a misalignment or a protrusion of screw is detected

- applying an external energy to the outside of the fracture for a predetermined duration and intensity

- performing the correction to either re-aligning by bending support structure or flattening protruding fastening means, and

- let support structure or fastening means cool down to regain strength.