Elastic element for the use in a stabilization device for bones and vertebrae and method for the manufacture of such elastic element

Abstract

A stabilization device for bones or vertebrae comprises a substantially cylindrical elastic element. The elastic element has a first end and a second end opposite to the first end. An elastic section extends between the first end and the second end. The elastic section includes at least first and second helical coils. The first and second helical coils are arranged coaxially so that the first helical coil extends at least in a portion between the second helical coil. The elastic element may form, for example, a portion of a rod, bone anchoring element, or plate.

1 - 25 . (canceled) 
     
     
         26 . A bone anchoring element for bones or vertebrae, comprising:
 a shaft with a free end;   a receiving portion opposite to the free end along a longitudinal axis of the shaft, the receiving portion having a U-shaped recess opening in a direction away from the free end of the shaft and forming two legs for accommodation of a rod therebetween; and   a locking element configured to secure to the receiving portion to lock the rod in the U-shaped recess;   wherein a first section of the shaft has a first end and a second end spaced apart along the longitudinal axis, the first section being cylindrical and having an exterior surface that is entirely threadless from the first end to the second end and an interior surface defining a coaxial bore extending from the first end of the first section to a portion of the shaft between the second end of the first section and the free end of the shaft; and   wherein the first section of the shaft further defines at least two recesses each extending through a wall of the first section and forming an opening on the exterior surface of the first section, wherein the exterior surface of the first section completely separates the respective openings of the at least two recesses from one another along an entire length of the cylindrical section from the first end to the second end.   
     
     
         27 . The bone anchoring element of  claim 26 , wherein the shaft further comprises a second section having an exterior surface that is threaded. 
     
     
         28 . The bone anchoring element of  claim 26 , wherein the first section of the shaft comprises first and second helical coil segments arranged coaxially around the coaxial bore and separated from one another in a circumferential direction by the at least two recesses. 
     
     
         29 . The bone anchoring element of  claim 28 , wherein the first and second helical coils are substantially identical to one another. 
     
     
         30 . The bone anchoring element of  claim 28 , wherein each of the first and second helical coils extends along an entire length of the cylindrical section from the first end to the second end. 
     
     
         31 . The bone anchoring element of  claim 28 , wherein the first helical coil is rotated approximately 180 degrees with respect to the second helical coil. 
     
     
         32 . The bone anchoring element of  claim 28 , wherein the first and second helical coils each has a pitch, and wherein the pitches of the first and second helical coils are identical. 
     
     
         33 . The bone anchoring element of  claim 26 , wherein the first section of the shaft is elastic. 
     
     
         34 . The bone anchoring element of  claim 26 , wherein the bone anchoring element comprises a bio-compatible material. 
     
     
         35 . The bone anchoring element of  claim 26 , wherein at least one of the first end and the second end of the first section of the shaft is provided with internal threads. 
     
     
         36 . The bone anchoring element of  claim 26 , wherein at least one of the first end and the second end of the first section of the shaft is provided with a cylindrical projection having an external thread. 
     
     
         37 . The bone anchoring element of  claim 26 , wherein the each of the recesses extends in a radial direction relative to the longitudinal axis through the wall of the first section of the shaft. 
     
     
         38 . The bone anchoring element of  claim 26 , wherein the shaft and the head are monoaxially connected. 
     
     
         39 . The bone anchoring element of  claim 26 , wherein the shaft has a spherical segment-shaped head at an end of the shaft opposite the free end, and wherein the receiving portion is a separate part which is provided with a seat for pivotably holding the head. 
     
     
         40 . The bone anchoring element of  claim 39 , further comprising a pressure element configured to lock the head against the seat. 
     
     
         41 . The bone anchoring element of  claim 26 , wherein the coaxial bore extends partially through the shaft and ends at the portion of the shaft between the second end of the first section and the free end of the shaft.