Bone repair device

The present invention is a bone repair means by arthrodesis, and an object of the present invention is to be used for regeneration of traumatic bone, particularly cervical spine bone.

In the surgical procedure for spinal disorders, the surgeon makes a partial or total resection of one or more vertebral bodies. The mechanical support previously provided by the excised bone is no longer present. To overcome this disadvantage, a method using a spinal rod made of titanium is generally known, and the space left after osteotomy is filled with an inert and biocompatible material. The spinal rod is inserted between two healthy vertebral bodies to provide initial support until the filled cement material hardens. Also, a single block of autologous bone is used, or bone from a bone bank, or a bone substitute.

In another technique, instead of the rod and biocompatible cement material, a bone fragment is inserted to fill the space after osteotomy and a rigid body called a "vertebral body" that supports the bone. A structure with a metal net is used. However, due to the installation of a rigid metal net, the adjacent vertebrae have to be moved aside, and surgery causes complications. In addition, the metal mesh is opaque to X-rays.

<p> One of the first objects of the present invention is to overcome the above-mentioned drawbacks.</p>

<p> The means of repairing a traumatized bone by bone grafting according to the present invention is to insert a transplanted bone fragment into a tube having a biocompatible wide mesh network structure coated with a bioabsorbable material. It is characterized by inclusion.</p><p> The mesh structure refers to either knitted or woven or non-woven fibers. It may or may not be bioabsorbable. The tube is installed to fill the space of the bone cavity. However, preferably, the tube is held in that position by a plate screwed to a healthy bone, and in the case of the spine, the tube is in that position by the plateaus of the upper and lower spines. Is held in.</p><p> The tube is biocompatible and has a tubular shape made of a bioabsorbable or non-bioabsorbable wide mesh fiber material. The coating material is a compound of poly-L-lactic acid (PLLA), polyglycolic acid or the like.<u style="single">Both</u>It is a compound of a polymer. Poly-L-lactic acid (PLLA) is absorbed over time while the grafted bone grows through the reticulum opening towards the healthy bone exposed by excision. The fiber tube alone would be too flexible to maintain the desired adhesion between the implant and the healthy bone wall of the excised surface.</p><p> By coating with a bioabsorbable material such as PLLA, the tube is cured for a period of time, the tube is given an appropriate anatomical morphology, and the bone implant is avoided in the early postoperative period. Therefore, it is possible to seal the tube against the movement of the transplanted bone.</p><p> According to another feature of the invention, in the case of the spine, the plate also has the function of holding the transplanted tissue in place by means of at least one screw whose end is implanted in the transplanted bone.</p><p> For the spine, total or partial removal of the vertebral body via the ventral route to leave room for the tube to be placed at the location where the implant is filled or the bone fragments are crimped. Is known to do. The purpose of the plate is to support good mechanical resistance of the structure and to enclose the filling product in a precisely separated compartment between each bone until the new bone hardens. It is to hold the tube.</p><p> The tube is X-ray permeable due to its composition in order to follow up the growth of the implant and monitor the colonization of the implant. The fiber tube will be adapted to the intervertebral shape by simply cutting and shaping with scissors. When PLLA is absorbed, the implant grows towards the rib wall and can fuse into the formation of the desired joint fixation, and the tube disassembles.</p><p> Other features and advantages of the present invention will be clarified by the following description with reference to the drawings for specific examples provided solely as non-limiting examples.</p>

In both of the reference drawings, the same indication indicates the same part. In FIG. 1, the transplanted tissue is composed of a generally cylindrical tube 1 containing the transplanted bone 2 and is inserted between two healthy spines V. The plate 3 is fitted along the length of the tube 1 and the plate 3 is screwed to the upper and lower spines that have undergone partial vertebral body excision. The plate 3 is held in place by tightening screws 4 at both ends thereof, and the screws 4 are fixed to two healthy spine Vs. The transplanted bone is connected to the plate 3 by at least one screw 5 at the center thereof in this example. According to the present invention, the wide mesh 6 disappears after a certain period of time to allow the transplanted bone to grow. Also in this drawing, the transverse direction of the spine and the spinous processes (not mentioned) are shown. FIG. 2 is an overhead view of the transplanted tissue placed in place within the cross section of the vertebral body V1. In this figure, the spinal canal (not mentioned) is schematicized. In the center of the plate 3 is a screw 5 that penetrates the tube 1 and is anchored in the implant bone in support of holding the tube 1 in place.

Although the above description relates to the spine, the present invention applies to all cases where a defect can be filled between two bones, especially with respect to the bone cavity, which is associated with excision. Undoubtedly, various variants, especially those implemented by equivalent technical means with alternatives, are within the scope of the present invention.

<figref num="1">Partial side view. A longitudinal section of the transplanted tissue placed between two healthy spines within the cavity of the resected spine is shown.</figref><figref num="2">A horizontal cross section of a partially resected spine seen overhead is shown.</figref>

Code description

1 Tube 2 Transplanted bone 3 Plate 4 Screws (for fixing the plate) 5 Screws (for fixing the transplanted bone) 6 Wide net V, V1 Spine