| 摘要 |
An extension device for a bone anchor is provided, wherein the bone anchor comprises an anchoring section (100) for anchoring in a bone and a receiving part (200) connected to the anchoring section. The receiving part comprises a central axis (C) and a channel (204) for receiving a rod, and sidewalls of the channel form two free legs (205a, 205b). The extension device comprises a first sleeve (1) with a first sleeve axis (c) which is coaxial to the central axis (C), wherein the first sleeve (1) is configured to be coupled to the receiving part (200) and decoupled from the receiving part (200); a second sleeve (2) with a second sleeve axis (c) coaxial to the central axis (C), wherein the second sleeve (2) is positioned within the first sleeve (1) and positionable relative to the first sleeve along the central axis (C) and wherein the second sleeve (2) is configured to be coupled to the receiving part (200) and decoupled from the receiving part (200); and a locking member (35) which in a first configuration inhibits decoupling of one of the first sleeve (1) or the second sleeve (2) from the receiving part (200) when the other one of the first sleeve (1) or the second sleeve (2) is still coupled to the receiving part. |
