Osteosynthesis screw, especially for application by a translaminar vertebral screw

• US 6,808,526 B1
• Filed: 05/14/2001
• Issued: 10/26/2004
• Est. Priority Date: 07/13/1998
• Status: Expired due to Fees

• Current Assignee: Sepitec Foundation
• Original Assignee: Sepitec Foundation
• Inventors: Dransfeld, Clemens, Mayer, Jörg, Wintermantel, Erich, Spirig, Walter, Tognini, Roger Roland, Magerl, Fritz
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): Kontos, Lina R
• Application Number:
  US09/743,538
• Time in Patent Office: 1,261 Days
• Field of Search: 606/65, 606/73, 606/67, 606/72
• US Class Current: 606/916
• CPC Class Codes: A61B 17/685 Elements to be fitted on the end of screws or wires, e.g. protective caps
• CPC Class Codes: A61B 17/8615 at the central region of the screw head
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/8635 Tips of screws
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61B 17/888 the driver bit acting on the central region of the screw head
• CPC Class Codes: A61B 2017/8655 with special features for locking in the bone
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

An osteosynthesis screw (1) used especially for application by a translaminar vertebral screw, comprises a shaft (3) at least partially provided with a thread (2) and a head (4) formed at one of its ends and having a notch (5) for a tool. Said shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4). The remaining section (B) of the shaft (3) up to the free end is produced without a thread. The head (4) has a diameter (D1) corresponding at least approximately to the outer diameter (DA) of the thread (2) and is provided with the inner notch (5) for a tool. The section (A) of the shaft (3) with the thread (2) has a configuration of uniform thickness, e.g. a trilobular configuration. Thus, the invention provides an osteosynthesis screw (1) exhibiting a short section (A) with a thread (2) and a long section (B) without a thread, said screw having a pull-out head (4) which is secured both axially and rotationally.

Claims

1. An osteosynthesis screw, in particular for application in translaminar vertebral-screw fixation, with a shaft which at least in part comprises a thread and a head formed at least at one of its ends and comprising a notch arrangement for a tool, characterized in that the shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4) and that the remaining section (B) of the shaft (3) up to the free end is without a thread (2), that the diameter (D1) of the head (4) corresponds at least approximately to the outer diameter (DA) of the thread (2) and comprises an inner notch arrangement (5) for a tool, and that at least one of the sections (A) of the shaft (3) with the thread (2) and the section (B) of the shaft (3) without the thread is non-circular and of uniform thickness.

2. The osteosynthesis screw according to claim 1, characterised in that the thread (2) of the shaft (3) is self-tapping or self-cutting.

3. The osteosynthesis screw according to claim 1 characterised in that the thread-free section (B) of the shaft (3) is cylindrical or conical, with section (A) of the shaft (3) comprising the thread (2) being non-circular, and of uniform thickness.

4. The osteosynthesis screw according to claim 1 characterised in that the thread (2) and the shaft (3) in this section (A) are cylindrical, with the threadless section (B) of the shaft (3) adjacent to the thread (2) being non-circular, and of uniform thickness.

5. The osteosynthesis screw according to claim 1 characterised in that section (A) of the shaft (3) comprising the thread (2) is located directly adjacent to the head (4).

6. The osteosynthesis screw according to claim 1 characterised in that the outer diameter (DG) of the thread-free section (B) of the shaft (3) at least approximately corresponds to the core diameter (DK) of the section (A) comprising the thread (2).

7. The osteosynthesis screw according to claim 1 characterised in that the axial length of the section (A) comprising the thread (2) is shorter than the axial length of the thread-free section (B) of the shaft (3).

8. The osteosynthesis screw according to claim 1 characterised in that at the head (4), at its deepest delimitation, the inner notch arrangement (5) for a tool comprises an additional recess or a pocket-like indentation (6).

9. The osteosynthesis screw according to claim 1 characterised in that the head (4) at its free end comprises an annular collar (7) whose diameter (DB) is smaller than the outer diameter-(D1) of the head (4).

10. The osteosynthesis screw according to claim 9, characterised in that the axial length (L) of the annular collar (7) is less than half the entire length (K), or less than a third of the entire length (K), of the head (4).

11. The osteosynthesis screw according to claim 9, characterised in that the annular collar (7) matches an annular sleeve (10) placed onto a tool (20), when in place said annular sleeve encompassing the annular collar (7) of the head (4) during the screwing process.

12. The osteosynthesis screw according to claim 1, characterised in that the free end of the thread-free section (B) of the shaft (3) comprises a section (17) which tapers off in a truncated-cone shape or in a hemispherical shape.

13. The osteosynthesis screw according to claim 1, characterised by a cover (18) for closing off the inner notch arrangement (5) for a tool, with said cover being able to be placed onto the head (4) in a non-positive or positive manner.

14. The osteosynthesis screw according to claim 13, characterised in that the outer diameter (D) of the cover (18) at least approximately corresponds to the outer diameter (D1) of the head (4).

15. The osteosynthesis screw according to claim 13, characterised in that the cover (18) at its outer limit comprises groove-like indentations (23).

16. The osteosynthesis screw according to claim 1, characterised by a tool (11) insertable in the inner notch arrangement (5) for a tool, of the osteosynthesis screw (1), with a sleeve (28) coaxially arranged on said tool, said sleeve accommodating in a coaxially encompassing manner at least a large part of the axial length of the head (4) of the osteosynthesis screw (1).

17. The screw of claim 1, wherein the section (A) or the section (B) of the shaft is trilobular or polygonal.

18. The screw of claim 1, wherein both the section (A) and the section (B) of the shaft are trilobular or polygonal.

19. An osteosynthesis screw, in particular for application in translaminar vertebral-screw fixation, with a shaft which at least in part comprises a thread and a head formed at least at one of its ends and comprising a notch arrangement for a tool, characterized in that the shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4) and that the remaining section (B) of the shaft (3) up to the free end is without a thread (2), that the diameter (D1) of the head (4) corresponds at least approximately to the outer diameter (DA) of the thread (2) and comprises an inner notch arrangement (5) for a tool, and that at least one of the sections (A) of the shaft (3) with the thread (2) and the section (B) of the shaft (3) without the thread is non-circular and of uniform thickness, in that the screw has a cover (18) for closing off the inner notch arrangement (5) for a tool, with said cover being able to be placed onto the head (4) in a non-positive or positive manner and in that the cover (18) comprises an annular stay (19) pointing towards the head (4), said stay being able to be placed onto the annular collar (7) of reduced diameter (DB) at the head (4).

20. An osteosynthesis screw, in particular for application in translaminar vertebral-screw fixation, with a shaft which at least in part comprises a thread and a head formed at least at one of its ends and comprising a notch arrangement for-a tool, characterized in that the shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4) and that the remaining section (B) of the shaft (3) up to the free end is without a thread (2), that the diameter (D1) of the head (4) corresponds at least approximately to the outer diameter (DA) of the thread (2) and comprises an inner notch arrangement (5) for a tool, and that at least one of the sections (A) of the shaft (3) with the thread (2) and the section (B) of the shaft (3) without the thread is non-circular and of uniform thickness, in that the screw has a cover (18) for closing off the inner notch arrangement (5) for a tool, with said cover being able to be placed onto the head (4) in a non-positive or positive manner and in that the cover (18) comprises annular stays (19, 22) projecting in both axial directions.

21. An osteosynthesis screw, in particular for application in translaminar vertebral-screw fixation, with a shaft which at least in part comprises a thread and a head formed at least at one of its ends and comprising a notch arrangement for a tool, characterized in that the shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4) and that the remaining section (B) of the shaft (3) up to the free end is without a thread (2), that the diameter (D1) of the head (4) corresponds at least approximately to the outer diameter (DA) of the thread (2) and comprises an inner notch arrangement (5) for a tool, and that at least one of the sections (A) of the shaft (3) with the thread (2) and the section (B) of the shaft (3) without the thread is non-circular and of uniform thickness, that the screw has a cover (18) for closing off the inner notch arrangement (6) for a tool, with said cover being able to be placed onto the head (4) in a non-positive or positive manner and that the cover (18) at its centre comprises a predetermined breaking point or sections connected in sector-shape by way of predetermined breaking lines, for producing an opening when inserting a tool (24) with a cone-shaped or pyramid-shaped tip (25).

22. An osteosynthesis screw, in particular for application in translaminar vertebral-screw fixation, with a shaft which at least in part comprises a thread and a head formed at least at one of its ends and comprising a notch arrangement for a tool, characterized in that the shaft (3) has a section (A) with a thread (2) on the end section oriented towards the head (4) and that the remaining section (B) of the shaft (3) up to the free end is without a thread (2), that the diameter (D1) of the head (4) corresponds at least approximately to the outer diameter (DA) of the thread (2) and comprises an inner notch arrangement (5) for a tool, and that at least one of the sections (A) of the shaft (3) with the thread (2) and the section (B) of the shaft (3) without the thread is non-circular and of uniform thickness, and characterised by a trunnion (27) which at least partly fills-in a section of the borehole (32) which remains free after embedded placement of the osteosynthesis screw (1), said trunnion being made from an elastic, histocompatible, non-absorbable material.