Implants and Methods for Correcting Tissue Defects

Abstract

The present invention relates to mosaic implant (15) comprising a plurality of mosaic plates (17) connected by a wire or mesh anchoring arrangement (9). Methods for forming such implants and methods for using said implants for correction of bone and soft tissue defects are described.

Description

FIELD OF THE INVENTION[0001]The invention relates to mosaic implants, methods for making such implants and methods for the correction of tissue defects.BACKGROUND OF THE INVENTION[0002]Bone tissue defects that cannot heal via tissue regeneration can be filled using autograph, allograph or synthetic scaffold materials. For large defects e.g. defects in the cranium or in long bones, healing of bone defect can be especially difficult. Scaffold strategies involve providing metal meshes or porous ceramic materials which new tissue can grow upon and / or into. Current strategies using metal mesh can give rise to problems with unhealed defects due to low new bone formation or infections. Currently used ceramics are mechanically weak and fragile which leads to a high risk of scaffold failure due to low mechanical strength. Metal meshes can be shaped in the operating theatre to closely fit the defect whereas the ceramics cannot be shaped after manufacturing and therefore have to be custom made...

AI Technical Summary

Benefits of technology

[0003]The present invention describes a mosaic implant, which can be used as a biomedical implant and which combines a wire or mesh anchoring system (a wire anchoring system comprises a plurality of wires, preferably crossing wires, where none of the wires are joined to each other while a mesh comprises at least two crossing wires joined at some or all of their intersections) and a biomaterial mosaic element, that can be shaped in the operating theatre and which provides increased combined bone in-growth and better mechanical properties compared to prior art systems. The implant comprises a mosaic element that combines at least one flexible high strength wire or mesh with at least two moulded solid mosaic plates. The invention can be employed for the correction of soft tissue defects and hard tissue defects. The biomaterial system can be composed of resorbable biomaterials and / or stable biomaterials such as polymers, ceramics and metals. Preferably the implant is osteo-conductive (i.e. can serve as a scaffold on which bone cells can attach, migrate, and grow and divide) or osteo-inductive (i.e. can serve to induce new bone formation), can be shaped in the operating room (OR) and have high mechanical strength. This is satisfied by using a mosaic structured implant system that combines a biomaterial anchoring system (for example a wire mesh) with a solid biomaterial system into a mosaic. This system has the beneficial effects of a mechanically strong wire mesh and an osteo-conductive and / or osteo-inductive solid part which means that the implant system can be easily shaped in the operation room by cutting the mesh into the desired geometrical shape and size. The solid plates, which are moulded at the intersections of the wires during manufacturing of the implant, are composed of an osteo-conductive and / or osteo-inductive material that facilitates bone in-growth onto the implant system.

[0004]Preferably the mesh is formed by intersecting wires to form a flat or a dished shape. In one embodiment of the present invention biomaterial mosaic plates are attached to intersections of the wire or mesh with a gap between the edge surfaces of adjacent plates. In this way a mosaic structure comprising wire-supported plates separated by gaps is formed. In another embodiment of the present invention a skin with a thickness which is less than the thickness of the biomaterial mosaic plates is formed between some or all of the mosaic plates. The skin is preferably frangible, and may be provided with lines of weakness, to allow selective breaking of it in order to shape the mosaic implant. Non-limiting examples of wires include polymers, shape memory alloys, Ti, Ti alloys (e.g. Ti6Al4V) and stainless steel. In the present application the word “wire” is intended to include filaments made of any such material. The biomaterials are preferably mouldable from the chemically bonded ceramic class of materials or a biopolymer, non-limiting examples include Ca-salts like: calcium sulphate, calcium phosphate, calcium silicate, calcium carbonate or combinations thereof. The materials are preferably moulded onto the wires or mesh using a non-aqueous water-miscible liquid or using a mixture of water and a non-aqueous water-miscible liquid, allowed to harden to form a mosaic implant in a water containing bath and subsequently the mosaic implant is released from the mould. After packing and sterilization the mosaic implant is ready to be used. The strength of the intersecting wires and, where present, the gaps between the plates are chosen so that a surgeon is able to shape the mosaic implant during an operation in order to adapt its shape to the tissue defect being corrected. The wider the gap between the plates the more the surgeon is able to deform the implant and hence produce a three-dimensional shape with complex curves. However wider gaps take longer to fill with bone tissue and in order to overcome this it problem while still allowing the formation of complex three-dimensional shapes it is possible to provide an implant with different gap widths between the plates—smaller gaps where the implant is intended to be substantially flat and wider gaps where the implant is intended to be curved.

Problems solved by technology

For large defects e.g. defects in the cranium or in long bones, healing of bone defect can be especially difficult.

Current strategies using metal mesh can give rise to problems with unhealed defects due to low new bone formation or infections.

Currently used ceramics are mechanically weak and fragile which leads to a high risk of scaffold failure due to low mechanical strength.

This method increases the bone in-growth but limits the ability to shape the mesh in the operating theatre as bending the wires can cause the powder to fall off and the method has not been tested on other metals than Ti.

Images