A bone fixation device comprises a compression unit, an expansion structure, an enclosure unit, and a retraction-preventing unit. The compression unit includes a first compression member and a second compression member. When the second compression member moves in a direction toward a distal end of the first compression member, the expansion structure is compressed by the first and second compression members for expansion and a first side hole is aligned with a second side hole so that a first axial hole and a second axial hole are in communication with gaps of the expansion structure through the first and second side holes. The enclosure unit is expanded by the expansion structure. The first compression member selectively constrains the second compression member by means of the retraction-preventing unit so that the second compression member is not allowed to take a linear movement in a direction toward a proximal end of the first compression member thereby keeping the expansion structure in the expanded state. As such, the present invention makes use of the retraction-preventing unit to prevent the expansion structure from collapsing thereby making the enclosure expanded.一種骨固定裝置,包括擠壓單元、展開結構、包覆單元及防退單元。擠壓單元包括第一、第二擠壓件,第二擠壓件往第一擠壓件的遠端的方向移動時,展開結構被第一、第二擠壓件擠壓而展開,第一側孔對準第二側孔,使第一、第二軸孔藉由第一、第二側孔與展開結構的空隙相通,包覆單元被展開結構撐開,第一擠壓件藉由防退單元選擇性地限制住第二擠壓件,使第二擠壓件無法往第一擠壓件的近端的方向直線移動,令該展開結構保持在展開狀態。藉此,本發明可藉由防退單元防止展開結構收縮,使包覆單元撐開。10‧‧‧擠壓單元11‧‧‧第一擠壓件13‧‧‧第二擠壓件20‧‧‧展開結構30‧‧‧包覆單元100‧‧‧椎骨200‧‧‧醫療填充物
