US 11,849,982 B2
Extension device for a bone anchor
Frank Heuer, Filderstadt (DE); and Marc Sanders, GC Bunde (NL)
Assigned to Silony Medical International AG, Frauenfeld (CH)
Appl. No. 16/623,990
Filed by Silony Medical International AG, Frauenfeld (CH)
PCT Filed Jun. 15, 2018, PCT No. PCT/EP2018/065987
§ 371(c)(1), (2) Date Dec. 18, 2019,
PCT Pub. No. WO2019/001990, PCT Pub. Date Jan. 3, 2019.
Claims priority of application No. 10 2017 114 273.8 (DE), filed on Jun. 27, 2017.
Prior Publication US 2020/0197052 A1, Jun. 25, 2020
Int. Cl. A61B 17/70 (2006.01)
CPC A61B 17/7085 (2013.01) [A61B 17/7032 (2013.01)] 26 Claims
OG exemplary drawing
 
1. Extension device for a bone anchor comprising an axial longitudinal direction, a peripheral direction concentric therewith, and a radial direction, the extension device extending in the axial longitudinal direction and engaging, by means of a radial projection, an engageable region on a head of the bone anchor in the axial longitudinal direction and also in the radial direction and being supportable against the head of the bone anchor in a direction opposite to the axial longitudinal direction such that the extension device can thereby be fixed to the head of the bone anchor so as to be detachable, yet also rigid in the axial longitudinal direction and non-rotatable, wherein the extension device comprises at least one separate shell par that extends in the axial longitudinal direction, the at least one shell part comprises the radial projection for engaging the engageable region on the head of the bone anchor, in that the shell part is rigid, but has a first deformable region, in that the first deformable region forms a spring element which extends in the axial longitudinal direction and can be deflected transversely to the axial longitudinal direction, in that the spring element comprises, proximally to the radial projection for engaging the engageable region on the head of the bone anchor, a radially inwardly projecting support region, by means of which the spring element and the shell part is supportable against the head of the bone anchor in the axial longitudinal direction such that the extension device can thereby be detachably fixed to the head of the bone anchor when the radial projection engages the engageable region on the head of the bone anchor, and in that the spring element is deflectable radially outwardly so as to detach the extension device, wherein the support region of said spring element is freed from the head of the bone anchor and the shell part can be moved relative to the head of the bone anchor distally out of the engageable region on the head of the bone anchor in the axial longitudinal direction, wherein the spring element is integral with the shell part, is delimited by a material-free slot in a wall of the shell part and transitions, at its proximal end, into the wall of the shell part.