Bioabsorbable elongated member

Abstract

A bioabsorbable elongated member including a first end and a second end and an elongated part therebetween. The elongated part includes a front end, a back end and a target point in which the front end terminates and the back end begins. The bioabsorbable elongated member possesses a predetermined orientation. The orientation of the bioabsorbable elongated member is alterable so that a bulge is formed in the bioabsorbable elongated member by mechanical, thermal or thermomechanical straining of the elongated member at the target point. The bulge forms a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member. A method for forming a local stopper, a part of a local stopper, or a bending point in a bioabsorbable elongated member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In figures only FIGS. 1b, 1c, 9e-9i, 12b show a bone to be fixed. However, a person skilled in the art will readily understand how the bone or tissue exists with respect to an elongated member in other figures.

In the figures,

FIG. 1 a shows an elongated member in a perspective view,

FIGS. 1 b and 1c show the elongated member inserted in a bone (the bone is shown in a cross-sectional view in order to show the elongated member,

FIGS. 2 a to 8c show variations of elongated members in perspective views,

FIGS. 9 a to 9d show an elongated member in a perspective view,

FIGS. 9 e to 9j show a schematical view how the elongated member of FIG. 9a is inserted in a cranium,

FIGS. 10 a to 10d show an elongated member in a side view,

FIGS. 11 a to 11d show possible head designs of an elongated member,

FIG. 12 a shows fractures in the distal end of a tibia,

FIG. 12 b shows the distal end of the tibia of FIG. 12a fixed with an elongated member,

FIGS. 13 a to 13e show one possible way to form a loop from an elongated member,

FIGS. 14 a to 14c show an elongated member with a retaining plate, and

FIG. 15 shows a cross-sectional view of elongated members which are used with cannulated screws and a retaining plate.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a shows a bioabsorbable elongated member which is a rod comprising a shaft 1. The cross-section of the rod may be cylindrical, square or any other suitable cross-section. The shaft 1 comprises a first end 2 and a second end 3 and an elongated part 4 therebetween. Needles 5 assisting in penetrating into a bone or tissue are attached to the both ends 2, 3 of the shaft 1. It is also possible that there is only one needle in one end of the shaft 1. The rod is delivered to its user as it is illustrated in FIG. 1a.

FIG. 1 b shows the bioabsorbable elongated member, i.e. the rod of FIG. 1a, in such a situation in which the user has inserted the rod in a drillhole in a broken bone 7 (number 8 denotes the fracture) and he has formed two bulges 6 in the shaft 1. Providing both ends with needles 5 makes it easier to fix rather complicated fractures.

FIG. 1 c shows the rod of FIGS. 1a and 1b when the excess of the shaft 1 has been cut off.

FIG. 2 a shows a rod comprising a shaft 1 and a head 9. The head 9 is formed by pressing down. The rod is delivered to its user as it is illustrated in FIG. 2a.

FIG. 2 b shows a situation in which the rod is inserted in a drillhole in a broken bone 7 (not shown). A bulge 6 forming a stopper is formed at the end of the shaft 1.

FIG. 3 a shows an elongated member whose shaft 1 comprises branches 10. The branches 10 of the elongated member may be inserted in drillholes in a broken bone. After the branches have been positioned, bulges 6 are formed outside the bone 7 (not shown) as shown in FIG. 3b.

FIG. 4 shows another variation of the elongated member of FIG. 3. The elongated member comprises a pre-manufactured head 11 which may be manufactured by pressing down. Branches 10 are inserted in a drillhole in a bone and bulges 6 are formed in the branches.

FIGS. 5 and 6 also show branched elongated members. FIGS. 5a and 6a show the elongated members before implanting, and FIGS. 5b and 6b show the elongated members after implanting. Bulges 6 are formed in each branch.

FIG. 7 a shows an elongated member, such as a pin which has a grooved surface. FIG. 7a also shows a first end 2, a second end 3, a front end 2a, a back end 3a and a target point T. The front end 2a begins from the first end 2 and terminates at the target point T. The back end 3a begins from the target point T and terminates at the second end 3. A bulge 6 is formed at the target point T. FIGS. 7b to 7e show that in principle a bulge 6 can be formed in the pin wherever desired, i.e. there can be several target points T.

FIG. 8 a shows an elongated member whose outer appearance resembles a cable tie. The elongated member has a flexible band section 12. The elongated member also comprises in its one end an eyelet 13 in which the other end can be threaded, as shown in FIG. 8b. After the elongated member has been inserted in a bone or tissue in a desired manner and threaded, a bulge 6 is formed outside the eyelet. Thus, the bulge forms a stopper as shown in FIG. 8c.

FIG. 9 shows an elongated member which is used e.g. in applications in which the cranium is fixed. The elongated member comprises a shaft 1 and a head 14. The shaft 1 of the elongated member is inserted through a drillhole in the cranium so that the head 14 of the elongated member is left under the cranium but over the dura. The head of the elongated member is a flat round plate as is natural due to the application. The diameter of the round plate may be at least 10 mm. The diameter of the shaft 1 may be around 10 mm.

After the elongated member has been inserted into the drillhole 17, the shaft 1 protrudes outside the cranium 16. An annular flat tightening ring 15 is inserted to the shaft 1, and a bulge 6 is formed outside the tightening ring 15, as shown in FIGS. 9c and 9h. The rest of the shaft 1 is cut as shown in FIGS. 9d and 9i.

FIG. 9 j shows the cranium, which is fixed with the elongated members, from above. A piece of the cranial bone 16b has been separated from the rest of the cranium 16a in order to make surgical operations. There are four drillholes in each corner of the piece of the cranial bone in which elongated members are inserted. The elongated members are fastened at the edge of the piece of the cranial bone 16b. Bulges are formed on the elongated member so that they keep the piece of the cranial bone 16b in its position (see FIG. 9i).

FIG. 10 shows an elongated member which is useful in applications in which the elongated member shall change its advancing direction. The elongated member may comprise a prefabricated head, or the head may be formed in situ. The advancing direction of the elongated member may be changed as desired as shown in FIGS. 10b and 10c by mechanically straining a certain point of the elongated member. When the material deforms at the point due to the heat caused by the mechanical straining, it is possible to form an angle in the elongated member. FIG. 10d shows a situation in which a desired length of the elongated member is used for the fixation and a bulge is formed at the end of the elongated member.

It is also possible to bend the elongated member without making the bulge 6 if the elongated member is sufficiently flexible. However, the bulge 6 increases the strength of the elongated member in its bending direction.

FIG. 11 shows variations of head designs of an elongated member. FIG. 11a shows a spherical head, FIG. 11b shows a flat round head, and FIG. 11c shows a spherical head whose joint with the shaft has been made gentle. FIG. 11d shows a truncated spherical head whose joint with the shaft has been made gentle.

FIG. 12 a shows fractures 8 in the distal end of tibia 17. FIG. 12b shows how the fractures 8 have been fixed with elongated members 18 and 19. The elongated member 18 is a pin which has been inserted in drillholes penetrating through the tibia 17. The elongated member 19 is a rod which has been inserted in a drillhole and whose advancing direction has been changed by forming bulges 6 outside the tibia 17.

The tibia is an example about possible targets of the elongated member. The principle of fixation is also the same with fractures in other bones: The elongated member is inserted in a drillhole or drillholes in a bone, and bulges are formed in the elongated member outside the bone in order to use them as stoppers or bending points.

FIGS. 13 a to 13e show one possible way to form a loop 20 from an elongated member. The straight elongated member of FIG. 13a is bent (FIG. 13b) and twisted (FIG. 13c) so that the loop 20 and two elongated tails 21 are formed. The legs 21 of the elongated member are threaded into the loop 20 (FIG. 13d). Bulges 6 are formed on the tails 21, and the tails 21 are cut underneath the bulges 6. The bulges 6 prevent the tails 21 from slipping out the loop 20.

FIGS. 14 a to 14c show an elongated member with a retaining plate 22. It is possible to form a bulge 6 on the elongated member before inserting the elongated member into a bone and/or tissue, or the bulge 6 can be formed after inserting the elongated member. The elongated member may be provided with a needle 5. After the elongated member has been inserted it forms either a loop around the bone and/or tissue, or it has been inserted in a drillhole or drillholes in the bone. It can be used for example for the fixation of the sternum. The ends of the elongated member are threaded through holes 23 in the retaining plate 22 and they are provided with the bulges 6. The elongated member is cut from the side of the bulge 6. The retaining plate 22 secures that the bulges 6 are prevented from slipping out from their position.

FIG. 15 shows elongated members which are used with cannulated screws 24 and a retaining plate 22. The cannulated screws 24 have been inserted in a bone and the elongated members are inserted via drillholes through the cannulated screws 24 and holes in the retaining plate 22. The ends of the elongated members are provided with bulges 6 which act as local stoppers. The cannulated screws 24 and the retaining plate 22 secures that the bulges 6 do not slip into the drillholes.

On the basis of the above description of the present invention and certain specific embodiments thereof, it will be readily apparent to those skilled in the art that many variations and modifications may be made to the present invention

Claims

1. A bioabsorbable elongated member, comprising: a first end;a second end; andan elongated part therebetween, the elongated part comprising a front end, a back end and a target point in which the front end terminates and the back end begins, the bioabsorbable elongated member possessing a predetermined orientation, wherein the orientation of the bioabsorbable elongated member is alterable so that a bulge is formed in the bioabsorbable elongated member by straining the elongated member mechanically, thermally or thermomechanically at the target point, the bulge forming a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member.

2. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member is radially expandable so that a bulge is formed in the bioabsorbable elongated member by moving the front end and the back end repeatedly with regard to each other at the target point, the bulge forming a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member.

3. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member is radially expandable so that a bulge is formed in the bioabsorbable elongated member by heating the elongated member at the target point, the bulge forming a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member.

4. The bioabsorbable elongated member according to claim 1, wherein in that the bioabsorbable elongated member is radially expandable so that a bulge is formed in the bioabsorbable elongated member by mechanical straining and heating of the elongated member at the target point, the bulge forming a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member.

5. The bioabsorbable elongated member according to claim 1, further comprising: a shaft.

6. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member comprises branches.

7. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member comprises a band.

8. The bioabsorbable elongated member according to claim 7, wherein the band comprises a loop at one end of the band.

9. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member comprises a separate tightening ring or a separate retaining plate.

10. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member comprises a needle or a bore bit.

11. The bioabsorbable elongated member according to claim 1, wherein the bioabsorbable elongated member comprises a copolymer of lactide and glycolide.

12. The bioabsorbable elongated member according to claim 11, wherein the bioabsorbable elongated member comprises 70 to 85 wt.-% of lactide and 15 to 30 wt.-% glycolide.

13. A method for forming a local stopper, a part of a local stopper, or a bending point in a bioabsorbable elongated member comprising a front end and a back end, the method comprising determining a target point where the front end terminates and the back end begins, andaltering the orientation of the bioabsorbable elongated member so that a bulge is formed in the bioabsorbable elongated member by mechanical, thermal or thermomechanical straining of the elongated member at the target point, the bulge forming a local stopper of the bioabsorbable elongated member, or a part of a local stopper, or a bending point of the bioabsorbable elongated member.

14. The method according to claim 13, further comprising: determining a target point where the front end terminates and the back end begins, andmoving the front end and the back end repeatedly with regard to each other at the target point, thereby forming a bulge used as the local stopper, the part of the local stopper, or the bending point.

15. The method according to claim 13, wherein before forming the bulge, a tightening ring or a retaining plate is inserted on the bioabsorbable elongated member.

16. The method according to claim 13, wherein after forming the bulge, the excess of the bioabsorbable elongated member is cut and/or pressed down.