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    • 专利摘要:
    Customized endoprosthesis for long bones of animals. The invention relates to a stent designed as an implant to be anchored to a long bone of an animal, it is adaptable and customizable to the size of the bone marrow. It comprises two pieces that allow primary anchoring to the bone by pressure: a first piece (1) made by additive manufacturing using polyether ether ketone (PEEK) to PEEK compounds and with a hole (12) inside; and a surgical metal rod (2). The first piece (1) includes an intramedullary zone (A) with secondary anchorage mechanisms to the bone (cavities, eyelashes, ridges, helices) and an extramedullary zone (B) with an umbrella-shaped projection (3) on whose proximal base The cortical bone rests in which the stent is inserted, which also has elements to cancel the relative rotation of the rod on the PEEK piece. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2736410A1
    申请号:ES201900106
    申请日:2019-07-12
    公开日:2019-12-30
    发明作者:De Cal Rosa Maria Mendaza；Quiros Jesús Rodriguez；Fernandez Salvador Peso
    申请人:Abax Innovation Tech；Universidad Complutense de Madrid；
    IPC主号:
    专利说明:

    [0001]
    [0002] CUSTOM ENDOPROOTHESIS FOR LONG BONES OF ANIMALS
    [0003]
    [0004] SECTOR OF THE TECHNIQUE
    [0005] The present invention belongs to the field of veterinary surgical implants, and more specifically to bone-anchored prostheses in anterior and posterior limbs of animals.
    [0006]
    [0007] BACKGROUND OF THE INVENTION
    [0008] The implantation of bone anchored prostheses has been practiced and researched in human medicine for more than twenty years. Currently, there are different models of implants for humans on the market, all of them made of metal, such as those included in US2016331422A1, ES2320829B1 and US9433505B2, in which different limb stent designs are shown. In the review written by Thesleff A. et al. ( Annals of Biomedical Engineering. 2018. Vol 46, 3: 377-391) the bone-anchored prostheses that exist for humans are analyzed for the direct transfer of external forces from the prosthesis to the skeleton. The following devices are described, with the improvements that have been introduced over time in each of them:
    [0009] - OPRA: there is a standard device and, also, the possibility of adapting it to different individuals and to different bones. It includes:
    [0010] - an internal cylindrical part where osseointegration takes place,
    [0011] - a percutaneous component that is inserted into the cylindrical part by pressure, - a nut that joins the two previous elements.
    [0012] It is made with an improved titanium alloy (TÍ6A14V) and, on the threaded part of the internal cylindrical part, a surface treatment is provided that provides a nanoporous structure that induces osseointegration.
    [0013] - ILP. Made with a medical grade cobalt-chromium alloy, it has a rough surface both in the region that is inserted into the medullary cavity of the bone, and in the subdermal region. Initially, the rough surface was designed as a macroporous surface with tripod-like structures of 1.5 mm, and the device included a support for the distal area of the cortical bone; In later versions of the device, the rough area of the distal part and the cortical bone support were removed.
    [0014] - OPL: there is a standard version for femur and another individually designed for tibia and for cases where a very short femur fragment remains. It is manufactured with TÍ6A14V and includes longitudinal grooves of 1 mm in the proximal area and a rough coating of titanium in the distal area, to favor osseointegration. - POP: a single component made with TÍ6A14V is described. The intramedullary part is divided into 3 regions: a near smooth zone !, a corrugated zone and a distal porous zone that includes a support region for the cortical part of the end of the bone.
    [0015] - ITAP: it is also a single component system made in TÍ6A14V. The proximal area of the intramedullary part has longitudinal grooves that aid in rotational stability. The distal and subdermal regions of the intramedullary part have hydroxyapatite coverage to favor osseointegration.
    [0016] - COMPRESS: the intramedullary part of the implant is attached to the bone by transverse nails placed in a bone anchoring element; It has a porous collar, to promote osseointegration, in the distal part of the bone.
    [0017] - Keep Walking Advanced: this is an improved version of the device described in ES2320829B1. This femoral implant is composed of a titanium stem, with a rough surface for osseointegration into the bone, and a polyethylene spacer that is assembled on the stem. This spacer rests on the distal end of the femur and is covered by the soft tissues of the stump, being the one that allows the loads to be transmitted again through the femur.
    [0018] - AEAHBM: refers to a TÍ6A14V implant, with the porous distal region made with tantalum and stretch marks in the intramedullary area.
    [0019]
    [0020] These implants are inserted by one of their ends directly into the bone, and the opposite end of the implant extends percutaneously from the residual limb allowing the coupling of an external prosthesis. This avoids the need for compression sleeves, necessary for classic prostheses, and eliminates the problems associated with them. In addition, it adds certain benefits such as improving the range of movement, the ability to walk, the comfort to sit, reduces energy expenditure and allows greater osteoperception, which improves the perception of limb movements. Although these implants also have complications such as marsupialization (epithelial retraction and pocket formation, due to a false closure of the skin), infection and avulsion.
    [0021]
    [0022] The described devices are usually composed of one or two pieces, depending on the mechanism of anchorage to the bone that is sought, which implies lengthening its implantation from one to two surgeries, respectively.
    [0023]
    [0024] These devices are manufactured in different types of surgical metals, since these materials have high strength and strength, in addition to, many of them, being chemically inert to contact with organic tissue. However, these materials are always selected with the implants in humans in mind. In animals, especially in dogs and cats, if these materials are used, it is by extrapolation since the high mechanical properties of metals are not required. In addition, metals have considerably greater rigidity than bone tissue, which entails the need to precisely adapt the recipient bone to the implant to avoid risks of cracks or fractures.
    [0025]
    [0026] The devices need proper bone anchorage and subsequent osseointegration. The primary anchor is either mechanical by threading, by pressure or by applying a compression force with transverse intraosseous needles, or by bone growth within the implant. As for osseointegration, all devices have a porous surface (nanoporous, microporous or rough) resulting from different techniques. Examples of this can be found in the following patents:
    [0027] - US4865608A: different types of grooves with dimensions between 350 and 635 pm are described.
    [0028] - WO2018055359A1: a surgical implant is described in whose body there are spines positioned obliquely giving rise to an acute angle with respect to the longitudinal axis of the device body. The length of the spines can be between 0.7 and 12 mm, and their width between 100 and 1000 pm.
    [0029] - US9173692B2: a bone orthopedic fixation device is described that has a helical thread that serves to keep the device in the correct position. - W02009105535A1: refers to another transcutaneous osteointegrable device to fix the prosthetic devices to the bone that has at least a part of the textured, coated or porous outer surface to facilitate bone fixation.
    [0030]
    [0031] The nature of these devices and the techniques for preparing them to achieve the desired benefits greatly increase their cost making it difficult to use these implants in animals. On the other hand, bone anchored implants are designed and designed for human and not for animals, when Load distribution of! The weight of a person and an animal are very different. In the case of people, the distribution of weight loads between the lower extremities is 50% for each limb, while in the case of animals, being quadrupeds, the distribution is, roughly, 60% in the forelimbs -30% per limb- and 40% in the hind limbs -20% in each limb. However, it is desirable to obtain bone-anchored implants for animals, adaptable and tailored implants for the size of the medullary canal of the animals' bones, allowing them to use their limb and avoiding complete limb amputation in the face of serious pathologies or injuries. severe of it.
    [0032]
    [0033] EXPLANATION OF THE INVENTION
    [0034] Customized endoprosthesis for long bones of animals.
    [0035]
    [0036] To facilitate and disseminate the use of bone anchored implants among animals, an endoprosthesis specifically designed for them is presented. This is intended to avoid complete limb amputation and consequent long-term orthopedic problems in animals with pathologies such as appendicular neoplasms, severe trauma, Irreversible neurological and vascular problems, which could be resolved with a distal amputation.
    [0037]
    [0038] In this specification, distal means the part of the limb that is furthest from the point of attachment of the limb itself to the body of the animal, and proximal the part of the limb that is closest to the point of attachment of the Own limb with the animal's body.
    [0039]
    [0040] By intramedullary, the space between the bone corticals is understood as the gap that exists where the bone marrow is located. By extramedullary means that area outside the medullary canal, protected by the skin, which is not in contact with the outside of the animal.
    [0041]
    [0042] Customizing means a custom design of the medullary canal of the concrete bone of the concrete animal for which the stent is manufactured. Similarly, other derivatives of this verb are used, such as customization or customizable.
    [0043] The stent is a bone anchored implant. It comprises two pieces that allow primary anchorage to the bone by pressure, placing them in two phases within the same surgery. Of the two pieces, the piece in contact with the bone is obtained by additive manufacturing using as a material the thermoplastic polymer polyether ether ketone (PEEK), or compounds thereof (PEEK with carbon fiber in different proportions) and the Another piece is a surgical metal rod. This ensures lower manufacturing costs, repeatability, customization and adaptation of the implant to the characteristics of the medullary canal of each patient, due to the variability that allows additive manufacturing, a production procedure by which the material is deposited layer by layer. in a controlled way where it is necessary, and that allows to develop a low number of units of customized devices with costs much lower than those required by subtractive manufacturing. In addition, the lower rigidity of PEEK and its compounds with respect to bone tissue causes the PEEK piece to yield volumetrically with respect to the medullary canal, which allows it to adapt better to the medullary canal, increase the area of bone-implant contact, require less precision in the treatment of the medullary canal prior to implantation, as well as a lower request in expansion of the bone of the animal, reducing the risk of cracks, compared with stents manufactured with metallic materials that are known in the state of the art.
    [0044]
    [0045] On the other hand, by obtaining a homogeneous transmission of the forces from the ground to the bone, the problems of implant osteopenia that can be seen in metal implants by a heterogeneous transmission are avoided, or at least reduced.
    [0046]
    [0047] The adaptation of the stent to each patient includes adaptation to the long bone of the limb that needs it, that is, to the posterior limb of the animal, which requires a cylindrical shape that adapts to the medullary canal of the tibia or femur, or the anterior limb of the animal, which requires an elliptical shape that adapts to the medullary canal of the radius as well as a pointed finish to facilitate its insertion into said medullary canal or a cylindrical shape to adapt to the medullary canal of the humerus.
    [0048]
    [0049] The primary anchoring procedure of the stent to the bone consists in the introduction with a slight pressure of the polymeric part inside the medullary canal. Subsequently, the surgical metal pressure rod is introduced into the first polymeric piece, the latter being the one that transmits part of the force to the bone. For to achieve this pressure, the designed polymeric piece is hollow, and its lightness or inner diameter is reduced to generate a radial force as the metal rod is introduced.
    [0050]
    [0051] The secondary anchoring mechanism consists of osseointegration. To achieve this, the intramedullary area of the first polymeric piece has a relief of channels of various shapes on its surface, which provides cavities, with a width and depth equal to or less than 1 mm. They can also include tabs or transverse ridges along the longitudinal axis of the intramedullary area to further improve the primary anchor, with a depth equal to or less than 2 mm.
    [0052]
    [0053] Optionally, the surface of the piece in contact with the bone can be treated with materials that favor osseointegration, such as hydroxyapatite, and / or antimicrobials, such as hinokithiol.
    [0054]
    [0055] Therefore, one aspect of the present invention relates to a custom stent for long bones of the anterior or posterior limb of animals comprising two parts:
    [0056] - a first piece for bone anchoring made of poly-ether-ether-ketone (PEEK) or PEEK compounds and with a hollow inside;
    [0057] - a surgical metal rod for its introduction into the hollow of the first piece that can be threaded or smooth, in the latter case, preferably prismatic.
    [0058]
    [0059] The first piece, made with PEEK or with PEEK compounds, includes an intramedullary and an extramedullary area. The intramedullary area includes a cylindrical body for long bones of both anterior and posterior limbs with a cylindrical spinal canal, and an elliptical body in the case of the radius of the animal's forelimbs. It is in this area where the secondary bone anchoring mechanism for osseointegration is found that has been previously mentioned and that can include tabs, ridges, cylindrical or prismatic cavities, or macroporous, propellers or combinations thereof.
    [0060]
    [0061] This first piece made with PEEK or with PEEK compounds has, in its most distal part, an area that we call extramedullary zone and that includes an umbrella-shaped projection. This umbrella-shaped projection is designed so that your size is suitable for resting on its proximal flat face the cortical part of the bone in which the stent is inserted and said projection may have a circular or polygonal shape. In addition, the umbrella-shaped projection has holes designed to be able to introduce soft tissue anchor sutures. The extramedullary area ends in a base that has transverse holes with sufficient diameter to introduce a wire.
    [0062]
    [0063] The first piece of the stent is hollow. Depending on the shape of the surgical metal rod to be used, the hole can have different shapes. It can have a hole with two different parts: a distal hole with a diameter greater than the diameter of the proximal hole, or it can be a prismatic shaped hole.
    [0064]
    [0065] In general, the diameter of the hollow of the first piece (as well as the proximal and distal recess when they have different diameters) varies depending on the diameter of the metal rod used in the stent. The dimensions of the gap in two parts, preferably, are:
    [0066]
    [0067]
    [0068]
    [0069] Where D is the diameter of the metal wand, Di is the value at which the diameter of the proximal recess should be reduced with respect to D, and D 2 is the value at which the diameter of the distal recess should be increased with respect to D, being these values of reduction or increase of Di and D 2 indicative and not limiting; The numerical values are expressed in millimeters. As for the total length of the hole, the thickness that must be between the proximal limit of the hole and the proximal limit of the first piece must not be less than 1mm.
    [0070]
    [0071] The interval of the thickness of the walls of the intramedullary zone of the first piece, for the cylindrical model, is from 0.80 mm to 5.2 mm and of the extramedullary zone is from 1.2 mm to 8.2 mm. Regarding the thickness interval of the intramedullary area in the elliptical model, designed for the radius, it should be noted that the hole is designed from the short diameter of the ellipse. Therefore, the thickness of the intramedullary area in the short diameter of the ellipse is 0.80 mm to 5.2 mm. The thickness of the wall in the long diameter is in relation to the geometry that is generated between the cylindrical bore and the elliptical intramedullary area.
    [0072]
    [0073] Optionally, the lower area of the intramedullary zone that connects the secondary anchoring mechanism and the umbrella-shaped projection can have a larger diameter to the diameter of the rest of the cylindrical body or the elliptical body, as long as it leaves in the proximal flat face of the umbrella-shaped projection sufficient space for the cortex of the bone in which the implant is inserted to rest.
    [0074]
    [0075] The invention may also include elements for nullifying torsional forces. These elements can be selected from the group consisting of: a nut screwed into the metal rod and which has holes tangential to the hole of the nut itself, so that these holes can be used to pass a wire through them and through the holes in the base of the extramedullary area; a nut that is screwed into the metal rod and a lock washer; one or two nuts that are screwed, both, into the metal rod and that remain in contact with the base of the first stent piece; a nut and an adhesive material between the nut and the base of the first piece.
    [0076]
    [0077] Preferably, the stent is custom designed for insertion into a long bone of the affected animal. As already mentioned, the long bone can be both the anterior limb and the posterior limb. In addition, it can be humerus or femur, or, preferably, it is designed for insertion into the tibia or radius. The sizes of animals in which it may be of interest to design and implant a stent can be very varied, from small animals such as rabbits, guinea pigs, ferrets, chinchillas or birds such as macaws, raptors, to more traditional companion animals, dogs and cats, as well as farm animals, large and small ruminants, or equidae. Preferably, the diameter of the long bone in which the stent is inserted is of reduced dimensions, meaning reduced dimensions of diameters equal to or less than 2.5 cm and, more preferably, equal to or less than 2.3 cm.
    [0078]
    [0079] Another aspect of the invention relates to a method for making a custom stent for animals that includes the following steps:
    [0080] - 3D design of the first part of the stent with the use of a CAD program ( Computer Aided Design) and based on personalized measurements of the dimensions of the medullary canal of the long bone, taken from the limb of the animal to be treated, obtaining the dimensions from! bone affected from conventional orthogonal radiological studies or, preferably, with CT (computed tomography) or MRI (magnetic resonance imaging);
    [0081] - transformation of! file obtained by the CAD program to an extension readable by a 3D printer through the use of a 3D lamination program, where all manufacturing parameters to be followed by the printer are determined;
    [0082] - application of additive manufacturing using FFF { Fused Filament Fabrication ), SLA ( Stereolithography ), SLS {Selective Laser Sintering), DLP {Direct Light Processing), LCD ( Light Crystal Display) or other additive manufacturing methodologies, using polymer as material thermoplastic poly-ether-ether-ketone (PEEK) or its compounds (PEEK with carbon fiber in different proportions).
    [0083]
    [0084] This method can be applied to any long bone of both the forelimbs and the hind limbs of the animals, and whether the bone in question has the cylindrical medullary canal or if it has the elliptical medullary canal, as occurs in the radius bone of the forelimb The method is especially suitable for the fabrication of stents for tibia and for the fabrication of stents for radio.
    [0085]
    [0086] BRIEF DESCRIPTION OF THE DRAWINGS
    [0087] To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description, where Illustrative and non-limiting nature has been represented. next:
    [0088]
    [0089] Figure 1. Shows a front view of the first piece (1) of PEEK or PEEK compounds and the surgical metal rod (2) assembled.
    [0090] Figure 2. Shows a perspective view of the separation of first piece (1) of PEEK or PEEK compounds and the smooth rod (2), with square section of rounded edges.
    [0091] Figure 3. Shows a front view of the first piece (1) of PEEK or PEEK compounds of the endoprottes, indicating the intramedullary area (A) and the extramedullary area (B).
    [0092] Figure 4. Shows a left side view of the first piece (1) of PEEK or PEEK compounds of the stent.
    [0093] Figure 5. Shows a perspective view of the first piece (1) of PEEK or PEEK compounds of the invention.
    [0094] Figure 6. Shows a perspective view of the first piece (1) of PEEK or PEEK compounds of the invention.
    [0095] Figure 7. Shows a bottom view of the first piece (1) of PEEK or PEEK compounds of the invention.
    [0096] Figure 8. Shows a top view of the first piece (1) of PEEK or PEEK compounds of the invention.
    [0097] Figure 9. Shows a cross-sectional view of the first piece (1) of PEEK or PEEK compounds of the stent, in which the recess (12) has two parts (distal recess (13) and proximal recess (14) ) of different diameter.
    [0098] Figure 10. Shows a cross-sectional view of the first piece (1) of PEEK or PEEK compounds of the stent, in which the recess (12) is in the form of a prism.
    [0099] Figure 11. Shows a bottom view of the first piece (1) of PEEK or PEEK compounds of the stent, in which the hollow (12) is in the form of a prism.
    [0100] Figure 12. Shows a perspective view of a surface variant of the cylindrical body (10) of the first PEEK part (1) or PEEK compounds of the invention, which has a propeller (18).
    [0101] Figures 13-17 They show frontal views of surface variants of the cylindrical body (10) of the first PEEK part (1) or PEEK compounds of the stent, which have cylindrical cavities (7), prismatic cavities (16), macroporous cavities (17) and / or tabs (8).
    [0102] Figure 18. Shows a front view of a variant of the first piece (1) of PEEK or PEEK compounds of the stent with an increase in the section of the cylindrical body in the lower area (19) of the intramedullary area and also , of the umbrella-shaped projection (3), which includes cylindrical cavities (7) and tabs (8) in the intramedullary zone (A).
    [0103] Figure 19. Shows a front view of a variant of the first piece (1) of PEEK or PEEK compounds of the stent with an increase in the section of the cylindrical body in the lower area (19) of the intramedullary area (A) and, also, of the umbrella-shaped projection (3), which includes cylindrical cavities (7) and ridges (9) in the intramedullary zone (A).
    [0104] Figure 20. It shows a top view of the first piece (1) of PEEK or PEEK compounds of the stent in which the umbrella-shaped projection (3) is polygonal in shape.
    [0105] Figures 21-23. They show front views of three options for blocking relative turns of the assembly of the first piece (1) and the rod (2), using nuts (21), wire (23) and / or adhesive material (24).
    [0106] Figure 24. Shows a left side view of the first piece (1) of PEEK or PEEK compounds for anterior limb radius, indicating the intramedullary zone (A) and the extramedullary zone (B) of the first piece (1). Cylindrical cavities (7) and ridges (9) and the proximal circular base tip (15) are indicated.
    [0107] Figure 25. Shows a front view of the first piece (1) of PEEK or PEEK compounds for anterior limb radius, indicating the intramedullary zone (A) and the extramedullary zone (B) of the first piece (1). Cylindrical cavities (7) and ridges (9) and the proximal circular base tip (15) are indicated.
    [0108] Figure 26. Shows a perspective view of the first piece (1) of PEEK or PEEK compounds for anterior limb radius, indicating the intramedullary zone (A) and the extramedullary zone (B) of the first piece (1). The elliptical body (11), with cylindrical cavities (7) and ridges (9), the proximal circular base tip (15) and the hollow (12) of the part (1) are indicated.
    [0109] Figure 27. Shows a bottom view of the first piece (1) of PEEK or PEEK compounds for anterior limb radius.
    [0110] Figure 28. Shows a top view of the first piece (1) of PEEK or PEEK compounds for anterior limb radius.
    [0111] Figure 29. Sample of the cross section of the first piece (1) of PEEK or PEEK compounds for radius of the anterior limb, in which the hollow (12) of the first piece (1) with its two parts can be seen: hollow distal (13) and proximal hollow (14).
    [0112]
    [0113] PREFERRED EMBODIMENT OF THE INVENTION
    [0114] The present invention is further illustrated by the following examples, which are not intended to be limiting in scope.
    [0115]
    [0116] Example 1. Preparation of the first piece (1) of PEEK or PEEK compounds.
    [0117] To make the first part (1) with PEEK or with PEEK compounds, a FunMat HT 3D Printer (from INTAMSYS, China) was used and the additive manufacturing technique was used, in this example by the FFF ( Fused Filament Fabrication) method ), and using PEEK (from 3D4Makers, the Netherlands). The PEEK was deposited layer by layer on the Z axis, with a layer height of 50pm and automatic extrusion width calculated the rolling program, and the molten filament was deposited on the X and Y axes with a speed of 30mm / s. The material was extruded by a 0.4mm diameter nozzle and an 0.92 extrusion multiplier. For the fusion of the filament an extruder temperature in a range of 390-410 ° C was used. During printing an ambient temperature of 90 ° C and bed temperature was maintained in a range of 130-160 ° C.
    [0118]
    [0119] Examples 2-10. First piece (1) of PEEK for long bones with cylindrical spinal canal.
    [0120] Example 2. A first PEEK part (1) was prepared as described in example 1. The first part (1) included two parts: a cylindrical intramedullary area (A) that will be placed proximally once it is inserted into the animal bone; an extramedullary area (B) that will remain distal. The dimensions of the first piece (1) made with PEEK were decided based on measurements previously taken from the medullary canal of multiple tibiae of dogs weighing approximately 25 kg and approximate cross size of 72 cm. In this case, the diameter of the intramedullary area (A) (including eyelashes / ridges) was set at 9.40 mm. On the other hand, the distal recess (13) of the piece was designed with an internal diameter of 6 mm, while in the proximal recess (14) the diameter narrowed to 5.7 mm, with a progressive decrease. In the extramedullary area (B) an umbrella-shaped projection (3) was made, which, in this example, was a spherical segment, that is, a solid body formed by the part of a sphere between two parallel planes that cut it , whose proximal flat surface has a circular shape with a diameter of 18.16 mm, with four triads of holes (4) of 1.20 mm in diameter oriented 90 ° to each other in pairs on the vertical axis of the first piece (1) (Figures 1-11). On the surface of the cylindrical body (10) that is part of the intramedullary area (A), cylindrical cavities (7) and tabs (8) were included as shown in Figures 3 6. Cylindrical cavities (7) were performed with a width and depth of 0.80 mm and the tabs (8) with dimensions of 1.00 x 2.00 mm. In the base (5) of the extramedullary area (B) of the first piece (1) 2 transverse holes (6) of 2 mm diameter were made. For the hollow (12) of the first piece (1) of PEEK, a smooth cylindrical distal hollow (13) of 17.21 mm in length and 6 mm in diameter was made, then made a progressive narrowing in 2, 5 mm in length of the lumen of the hole (12) to give rise to a proximal hole (14) of 25.21 mm in length and 5.7 mm in diameter (figure 9) that widened again in 2.5 mm in length up to a diameter of 6.1 mm in the last 1.54 mm of the hole (12) of the first piece (1). Therefore, the length of the gap (12) is 46.46 mm and the total length of the first piece (1) is 50.21 mm. The thickness of the first piece, taking into account a cross-section along the longitudinal axis of the piece, in the intramedullary area (A) varies from 0.96 to 1.85 mm. Regarding the extramedullary area (B), due to the three forms it contains, the thickness varies from 6.4 mm to 0.9 mm.
    [0121]
    [0122] Example 3. A first piece (1) was prepared as described in example 2 but in the cylindrical body (10) no tabs (8) were included but two propellers (18) of triangular section, with an equilateral triangle with a length from its sides of 0.90 mm (figure 12 ).
    [0123]
    [0124] Examples 4-7. Different first pieces (1) of PEEK were made as described in example 2 in which the cylindrical cavities (7) and / or the tabs (8) included on the cylindrical body (10) were changed to: only cylindrical cavities ( 7) (figure 13); prismatic cavities (16) (figures 14 and 16); macroporous cavities (17) (figure 15); macroporous cavities (17) and tabs (8) alternating as rings along the surface of the cylindrical body (10) (figure 17) all of them smaller than 1 mm, that is, all of them sized between 250 pm and 1000 pm.
    [0125]
    [0126] Example 8. A first piece (1) was prepared as described in example 2 in which the umbrella-shaped projection (3) was made in a polygonal shape (figure 20) and the profile section (20) of the lower third (B) of the first piece (1) made with PEEK, with greater smoothing in the change of area of the projection to the union with the base (5) of the lower third (B) (figure 18) than in the examples previous. In addition, the section of the cylindrical body in the lower area (20) of the intramedullary area (A) was increased. Therefore, the thickness of the first piece, in the extramedullary area (B), due to the three forms it contains, varies from 5.22 mm to 2.34 mm. In this example, in the intramedullary area (A), the thickness is 1.85 mm.
    [0127]
    [0128] Example 9. Following example 8, instead of tabs (8), crests (9) were included on the cylindrical body (10) (Figure 19).
    [0129]
    [0130] Example 10. A first piece (1) of PEEK was prepared as in example 2 in which the hole (12) was made prismatically as seen in Figures 10 and 11.
    [0131]
    [0132] Example 11. First piece (1) of PEEK for radius of the anterior limb.
    [0133] A first piece (1) of PEEK was made from the dimensions previously taken from the elliptical medullary canal of the radius bone of an anterior limb (Figures 24-29) of a dog with an approximate weight of 25 kg and an approximate cross size of 72 cm. The dimensions of the intramedullary area (A) were 5.80 mm in short diameter and 7.40 mm in long diameter with a length of 42 mm. On the other hand, the distal recess (13) of the piece was designed with an internal diameter of 4 mm, while in the proximal recess (14) the diameter narrowed to 3.7 mm, with a progressive decrease. The surface of the elliptical body (11) included cylindrical cavities (7) and ridges (9). On the other hand, at the proximal end of the elliptical body (11), opposite the extramedullary area (B), a circular base tip (15) was made to facilitate the insertion of the first piece (1) into the bone of the forelimb This circular base tip (15) was made solid and of the same diameter as the short diameter of the intramedullary area (A) and total length of 8 mm, where the body is composed of two trunk-shaped areas, 1.73 mm high the proximal and 4.00 mm the distal, joined by a cylindrical area of 4.00 mm in diameter and 2.27 mm high. The extramedical area (B) of the first piece (1) was made including a circular umbrella-shaped projection (3), as described in example 2, with a diameter in the proximal flat surface of 13.77 mm. The length of the hole (12) is 49 mm and the total length of the first piece (1) is 57.23 mm. Therefore, a thickness of the first piece was obtained, in the intramedullary area (A) of 2.8 mm in the long diameter of the ellipse and 1.25 mm in the short diameter. Regarding the extramedullary area (B), the wall thickness varies from 5.4 mm to 2.4 mm.
    [0134]
    [0135] Example 12. Threaded rod (2) of surgical material.
    [0136] A grade 5 titanium rod (2) was made in a cylindrical, threaded shape (Figure 1 and 21-23), 78.96 mm long and M6 metric.
    [0137]
    [0138] Example 13. Prismatic wand (2) of surgical material.
    [0139] A grade 23 titanium rod (2) was made, with the smooth surface, of square section with rounded angles. Its dimensions were: 78.96 mm in length and 5.00 mm in side for use with the first piece (1) made as indicated in example 10 (figure 2).
    [0140]
    [0141] Example 14. Insertion of the stent in an ex vivo model .
    [0142] Trials were performed in ex vivo models composed of tibiae and canine radii of animals weighing around 25 kg.
    [0143] To assemble the stent, two steps were followed:
    [0144] - Placing, with a slight pressure, the first piece (1) of PEEK made in Example 2, in the medullary canal, previously prepared for reception. To prepare the medullary canal, the most distal cross-section that allowed the pathology of the anima! Was performed above the distal epiphysis of the tibia; then, the drilling of the spinal canal was performed with a drill of the smallest diameter size of the hollow of the medullary canal; in this case, it was decided that drilling would be done with a 9 mm diameter drill bit since the medullary canal of the tibia was in the range of 9.00-9.90 mm. The first piece (1) yielded volumetrically to adapt to the medullary canal.
    [0145] - Insertion of the surgical metal threaded rod (2) of example 12 into the first PEEK part (1) up to the maximum length of the hollow (12) of the latter, applying torsion-pressure.
    [0146] In order to secure the first piece (1) of PEEK and the threaded rod (2) regarding the relative rotation of one piece with respect to the other, different variants were tested:
    [0147] - Placing a nut (21), on the threaded rod (2), with tangential holes (22) to the hole of the nut itself (21), through which a wire (23) passes which in turn passes through the holes ( 6) of the base (5) of the extramedullary area (B) (figure 21).
    [0148] - Placement of a nut (21) and a lock washer.
    [0149] - Placing one or two nuts (21), on the threaded rod (2), which remain in contact with the base (5) of the first piece (1) of PEEK (figure 22).
    [0150] - Placing a nut (21), on the threaded rod (2), and an adhesive material (24) between the nut (21) and the base (5) of the first PEEK part (1) (figure 23).
    权利要求:
    Claims (16)
    [1]
    1. Customized endoprosthesis for long bones of animals comprising two parts: - a first piece (1) for bone anchoring made of polyether ether ketone (PEEK) or PEEK compounds and with a hole (12) inside;
    - a surgical metal rod (2) for its introduction into the recess (12) of the first piece (1).
    [2]
    2. Tailor-made stent according to claim 1 whose first piece (1) includes: - an intramedullary area (A) with a cylindrical body (10) for long bones with cylindrical medullary canal of the hind limbs and anterior limbs, or an elliptical body (11) for the radius of the forelimbs, with a secondary anchoring mechanism to the bone for osseointegration of said intramedullary area (A) that is selected from the group consisting of: eyelashes (8), ridges (9), cylindrical cavities (7), prismatic cavities (16), macroporous cavities (17), propellers (18) or combinations thereof;
    - an extramedullary area (B) that includes an umbrella-shaped projection (3) of adequate size so that the cortical part of the bone in which the stent is inserted and with holes (4) with a sufficient diameter rests in its proximal base to be able to introduce soft tissue anchor sutures; and a base (5) with transverse holes (6) with sufficient diameter to be able to introduce a wire (23).
    [3]
    3. Customized endoprosthesis according to any of the preceding claims wherein the hollow (12) of the first piece (1) is formed by a distal recess (13) and a proximal recess (14) whose diameter is smaller than the distal recess (13).
    [4]
    4. Customized endoprosthesis according to claim 3 wherein the dimensions of the gap in two parts are:

    [5]
    5. Tailor-made stent according to any of claims 1-2 wherein the hole (12) of the first piece (1) has a prismatic shape.
    [6]
    6. Tailored stent according to any of the preceding claims wherein the length of the recess (12) of the first piece (1) is such that it leaves a thickness between the proximal boundary of the recess (12) and the proximal boundary of the first piece (1) equal to or greater than 1mm.
    [7]
    7. Customized endoprosthesis according to any of the preceding claims in which the secondary anchorage mechanisms to the bone have width and depth:
    - equal to or less than 1 mm, in the case of cavities;
    - equal to or less than 2 mm, in the case of ridges, eyelashes and propellers;
    [8]
    8. A custom stent according to any of the preceding claims wherein the lower area (19) of the intramedullary area (A) connecting the secondary anchoring mechanism and the umbrella-shaped projection (3) has a diameter greater than the diameter of the rest of the cylindrical body (10) or of the elliptical body (11), where said lower area (19) leaves space in the proximal face of the umbrella-shaped projection (3) so that the cortical bone rests on which it is insert the stent.
    [9]
    9. A custom stent according to any of the preceding claims wherein the protrusion in the form of an umbrella (3) has a circular or polygonal shape.
    [10]
    10. Customized endoprosthesis according to any of the preceding claims wherein the surgical metal rod (2) is threaded.
    [11]
    11. Customized endoprosthesis according to any of claims 1-9 wherein the surgical metal rod (2) is prismatic in shape.
    [12]
    12. Customized endoprosthesis according to any of the preceding claims which includes elements for canceling the torsional forces that can be selected from the group consisting of: a nut (21) suitable for the threaded rod (2), and with tangential holes (22) to the hole of the nut itself (21), where a wire (23) passes through the holes (6) of the base (5) of the lower third (B); a nut (21) and a lock washer; one or two nuts (21) suitable for the threaded rod (2), which remain in contact with the base (5) of the first piece (1); a nut (21) suitable for the threaded rod (2), and an adhesive material (24) between the nut (21) and the base (5) of the first piece (1).
    [13]
    13. Tailor-made stent according to any of the preceding claims wherein the surface of the first piece (1) is coated with materials that favor osseointegration and / or with antimicrobial effect.
    [14]
    14. Customized endoprosthesis according to any of the preceding claims for the tibia or radius of animals,
    [15]
    15. Method for making a custom stent for long bones of animals as defined in the preceding claims which includes:
    - 3D design of the first piece (1) with the use of a CAD ( Computer Aided Design) program based on the measurements taken from the medullary canal of the bone to be treated;
    - transformation of the file obtained through the CAD program to an extension readable by a 3D printer,
    - application of additive manufacturing using as a material the poly * ether-ether-ketone thermoplastic polymer (PEEK) or its compounds (PEEK with carbon fiber in different proportions).
    [16]
    16. Method according to claim 15 wherein the first piece (1) is designed for the tibia or radius of an animal.
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    同族专利:
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    ES2736410B2|2020-11-03|
    WO2021009394A1|2021-01-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4158895A|1978-02-09|1979-06-26|Nasa|Prosthesis coupling|
    WO2008092967A1|2007-02-02|2008-08-07|Tequir, S.L.|Modular femoral endoprosthesis|
    WO2009105535A1|2008-02-19|2009-08-27|North Carolina State University|Transcutaneous osseointegrated device for prostheses|
    US20130006356A1|2011-06-30|2013-01-03|Fellowship Of Orthopaedic Researchers, Inc.|Magnetic prosthetic implants and methods thereof|
    US20180049897A1|2016-08-17|2018-02-22|Arizona Board Of Regents On Behalf Of Arizona State University|Osseointegratable prosthetic device and manufacturing method|WO2021139915A1|2020-01-09|2021-07-15|Adler Ortho S.P.A.|Orthopedic implant with diaphyseal and/or metaphyseal filling|
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    ES201900106A|ES2736410B2|2019-07-12|2019-07-12|Custom Endoprosthesis for Animal Long Bones|ES201900106A| ES2736410B2|2019-07-12|2019-07-12|Custom Endoprosthesis for Animal Long Bones|
    PCT/ES2020/070399| WO2021009394A1|2019-07-12|2020-06-18|Custom-made endoprosthesis for long bones of animals|
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