Particles made of biocompatible metallic materials for vertebroplasty

Abstract

The invention relates to a particle made of a biocompatible metallic material, in particular titanium or a titanium alloy, for use in vertebroplasty operations. The particle (10) according to the invention is characterized in that it has a spherical shape and comprises a central core (13) with a solid structure, said central core also being spherical and having an outer surface (13a) from which protrude a first radial rib (11) and a second radial rib (12), also with a solid structure. The radial ribs (11, 12) are arranged according to two mutually perpendicular diameters. The particle (10) according to the invention also comprises a portion (14) with a trabecular structure, which portion (14) extends between the outer surface (13a) of said central core (13) and the outer surface (10a) of the particle itself.

Description

Technical Field

[0001] The present invention relates to a specific configuration of particles made of a biocompatible metallic material, in particular titanium or its alloys, for use in vertebroplasty or percutaneous kyphoplasty procedures.

[0002] Vertebroplasty or kyphoplasty is a treatment used for patients with vertebral compression fractures. Background Art

[0003] The Applicant is the owner of granted Italian patent nr. 0001425055 and pending European patent application EP3169375, from which the latter application claims priority, and describes particles made of biocompatible material suitable for use in vertebroplasty procedures.

[0004] Therefore, a previous patent of the same applicant proposes a prosthetic device made of a biocompatible material, in particular of titanium or its alloys, in the form of particles comprising at least an outer surface portion having a porosity suitable for allowing bone fusion and promoting bone growth.

[0005] This technical solution provides a novel alternative to the systems known in the prior art to replace bone cement such as PMMA (polymethyl methacrylate).

[0006] The most widely used technique involves the use of a balloon: after creating the required access device, the surgeon inserts a cannula into the collapsed vertebra, thereby inserting the balloon into the body of the vertebra, in the area where the collapsed cancellous bone no longer performs its supporting function.

[0007] With the patient in a tilted and misaligned position, a cannula is inserted directly into the body of the vertebra through a transpedicular access.

[0008] The entire operation was performed under endoscopic examination.

[0009] Once the correct position within the vertebral body is reached, a bone compression device, which is simply a balloon inflated by a fluid or equivalent system, is inserted through the cannula.

[0010] The function of the balloon is to compress the trabeculae of the cancellous bone of the vertebral body while expanding the internal space of the collapsed vertebra.

[0011] Once the space of the vertebra has been inflated by the balloon, the balloon is withdrawn and a cement commonly used in orthopedics, also known as PMMA (polymethyl methacrylate), is inserted again via the cannula into the space thus formed.

[0012] The use of cement in kyphoplasty has the advantage of immediately ensuring primary stability, ie resistance to the compressive loads acting on the spine, which ensures a very short hospital stay for the patient, so that the patient himself can leave within a few days after the operation.

[0013] According to the teaching of EP3169375, the applicant overcomes the disadvantages that adversely affect the conventional technique when using bone cement by using particles made of biocompatible material for vertebroplasty procedures.

[0014] Based on these teachings, the applicant has developed a specific and preferred particle configuration made of a biocompatible metallic material, such as titanium or its alloys, for use in vertebroplasty, as described in detail below. SUMMARY OF THE INVENTION

[0016] The main object of the present invention is to provide particles made of a biocompatible metallic material, such as titanium or its alloys, which are optimized for use in vertebroplasty procedures.

[0017] In this task, the object of the present invention is therefore to provide particles made of a biocompatible metallic material, for example particles made of titanium or its alloys, for vertebroplasty, which provide optimal primary stability, i.e. resistance to compressive loads acting on an optimized spine and at the same time allow optimized bone fusion and bone formation capacity.

[0018] Another object of the present invention is to provide particles made of biocompatible metallic material for vertebroplasty which can be introduced into damaged vertebrae via the same cannula that a surgeon uses to insert a balloon according to conventional surgical techniques, the balloon acting to compress the trabeculae of the cancellous bone of the vertebral body and simultaneously expand the internal void of the collapsed vertebra.

[0019] Furthermore, an object of the invention is to provide particles made of biocompatible metallic material for vertebroplasty, the geometry of which is such as to have an elasticity as close as possible to the average elasticity of the reference bone of the vertebra to be restored and which must stimulate growth and bone fusion of said bone.

[0020] This object and the above and other purposes of the present invention are achieved by particles made of a biocompatible metallic material for vertebroplasty according to claim 1 .

[0021] Further features of the particles made of biocompatible metallic material for vertebroplasty according to the invention are set out in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features and advantages of the particles made of biocompatible metallic material for vertebroplasty of the present invention will be described by the following detailed description, non-limiting examples and with reference to the accompanying drawings, in which:

[0024] - Figure 1 A general perspective view showing particles made of a biocompatible metallic material according to the present invention;

[0025] - Figure 2 Display as Figure 1 Cross-section of the particle shown;

[0026] - Figure 3 Display and Figure 2 Schematic cross-sectional view of the same;

[0027] - Figure 4 A schematic perspective view showing a Dode-thin structure representing the trabecular portion of a particle of the present invention;

[0028] - Figure 5A and 5B as well as Fig. 6A and 6B The Dode-thin structure of the trabeculae of the particles of the present invention is shown. DETAILED DESCRIPTION OF THE INVENTION

[0030] According to the invention, particles made of biocompatible metallic material, more particularly based on titanium and / or its alloys, are prepared having characteristics that allow them to be inserted into the body of the vertebrae during an operation, to resist the main loads and, over time, to carry out bone fusion of said particles and to stimulate bone regeneration.

[0031] The particle 10 of the present invention preferably has a spherical shape, with a maximum outer diameter of less than 4 mm, more preferably an outer diameter of 3.3 mm, and has a substantially spherical central core 13, from which a first radial rib 11 and a second radial rib 12 arranged in two diameters perpendicular to each other protrude and extend.

[0032] The first radial rib 11 and the second radial rib 12 preferably have a solid structure made of a biocompatible metal material constituting the particle 10, preferably titanium or an alloy thereof.

[0033] Therefore, these solid ribs 11, 12 have the appearance of mutually perpendicular radial strands, which have the same material as the central core 13, which also has a solid structure.

[0034] See, for example, the accompanying drawings and in particular Figure 1 The particle 10 of the present invention also comprises a region 14 having a trabecular structure, which affects the portion of the particle 10 extending from the outer surface 10a of the particle itself to the outer surface 13a of the central core 13, which can be seen, for example, Figure 2 and 3 .

[0035] Especially in Figure 3 In FIG. 1 , which shows a cross section with a radial plane through a particle 10 according to the invention, reference numeral 14 denotes a region with a trabecular structure, the remainder of the particle being a central core 13 extending from radial ribs 11 and 12 and having a solid structure.

[0036] See again Figure 3 , the letters a, b and c represent respectively: the width of the ribs 11 and 12, preferably 0.5 mm; the internal diameter of the central core 13, preferably equal to 2.5 mm; and the external diameter of the particle 10, preferably equal to 3.3 mm.

[0037] The particles 10 of the invention are advantageously prepared by a manufacturing technique involving local microcasting of powders (metal or polymer) by means of a high-energy electron beam.

[0038] These technologies, called EBM (Electron Beam Melting), are currently the most advanced manufacturing technologies that allow the manufacture of objects with very complex geometries and different surface roughnesses, starting from a computer design of the final product, using programmed machines for directing the action of an electron beam.

[0039] Electron beam melting is a relatively new rapid prototyping technology for producing implant structures and is capable of producing complex three-dimensional geometries.

[0040] Using this technology, the Applicant has developed the particles 10 of the present invention, in which the parts with a regular trabecular structure have pores with a size between one trabecula and another of the order of hundreds of micrometers.

[0041] More particularly, the regular trabecular structure has a pore diameter of 400-800 microns, even more preferably a pore diameter of about 600 microns, preferably 640 microns.

[0042] In particular, since titanium or titanium alloy has an elastic modulus very close to that of natural trabecular bone, the trabecular structure made of titanium or titanium alloy restores the physiological transfer of loads, avoids bone damage and actually promotes bone regeneration.

[0043] Referring again to the specific configuration of the particle 10 according to the invention, the zone 14 with a trabecular structure relates at least to the portion of the particle 10 extending from the outer surface of the particle itself to the central core 13, which advantageously has a trabecular structure obtained via an EBM manufacturing technique using a software element of a known type called "Dode-thin".

[0044] See especially Figure 4 ,This figure schematically shows the software implementation process of the "Dode-thin" type grid structure; Figure 5AThe orientation of the "Dode-thin" element is shown, which corresponds to Figure 5B A hexahedral geometry conforming to the surface of the three-dimensional trabecular structure as shown; and Fig. 6A The orientation of the "Dode-thin" element is shown, which corresponds to Figure 6B The octahedral geometry shown corresponds to the diagonal (45°) of the three-dimensional trabecular structure.

[0045] From having e.g. Figure 4 Starting with the design of the details shown, the CAD-CAM software implements the grid construction based on the known "Dode-thin" components, and finally obtains the following through EBM technology: Figure 1 and 2 Products shown.

[0046] The Applicant has also demonstrated that the specific construction of the particle 10 according to the invention, in particular the presence of solid radial ribs 11, 12 extending from a solid central core 13, and a large trabecular area 14 extending from the outer surface 13a of the central core 13 to the exterior 10a of the particle 10, enables a mechanical behavior during in vivo implantation, allowing loads to be supported and the primary stability of the implant to be immediately achieved.

[0047] From the foregoing description it is apparent that the characteristics of particles made of biocompatible metallic materials, particularly titanium or its alloys, and the associated advantages for use in vertebroplasty procedures.

[0048] It should be understood that the particles for use in vertebroplasty procedures are susceptible to various modifications and / or variations within the scope of the present invention, the scope of which is defined by the appended claims.

[0049] In particular, the materials as well as the dimensions can also be varied according to requirements.

Claims

1. A particle (10) made of a biocompatible metallic material titanium or titanium alloy for use in a vertebroplasty operation, characterized in that The particle has a spherical shape and comprises a central core (13) with a solid structure, the central core is also spherical and has an outer surface (13a), from which protrude a first radial rib (11) and a second radial rib (12), also with a solid structure, which are arranged according to two mutually perpendicular diameters, and the particle comprises a portion (14) with a trabecular structure, which extends between the outer surface (13a) of the central core (13) and the outer surface (10a) of the particle itself.

2. The particle (10) according to claim 1, characterized in that The first radial rib (11) and the second radial rib (12) extend from the central core (13) to the outer surface (10a) of the particle (10).

3. The particle (10) according to claim 1 or 2, characterized in that The external diameter (c) of the particle is equal to 3.3 mm and the diameter (b) of the central core (13) is equal to 2.5 mm.

4. The particle (10) according to claim 1 or 2, characterized in that Each of the first radial rib (11) and the second radial rib (12) has a width of 0.5 mm.

5. The particle (10) according to claim 1 or 2, characterized in that The particles were prepared by electron beam melting (EBM) rapid prototyping technology.

6. The particle (10) according to claim 1 or 2, characterized in that The portion (14) having a trabecular structure has a pore diameter of 400-800 micrometers.

7. The particle (10) according to claim 1 or 2, characterized in that The part (14) having a trabecular structure has a trabecular structure manufactured by electron beam melting (EBM) technology using a so-called "Dode-thin" element.

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