An expanding implant (600) for insertion between first and second regions of hard tissue, the implant comprising: (a) a backbone (630) having a surface for contacting the first region of hard tissue, said backbone comprising a proximal portion (688a) and a distal portion (688b), said backbone assuming an initial length and being shortened towards a second length by relative movement of said proximal portion and said distal portion； (b) a first segment (640c) hingedly connected to a distal region of said distal portion (688b) of said backbone； (c) a second segment (640a) hingedly connected to a proximal region of said proximal portion (688a) of said backbone； and (d) an intermediate segment (640b) having a surface for contacting the second region of hard tissue, said intermediate segment being hingedly connected to said first segment and to said second segment such that shortening of said backbone from said initial length towards said second length causes an increase in a distance between said surfaces of said backbone and said intermediate segment, and wherein said intermediate segment and said backbone are each formed with openings (623) through said respective surfaces, said openings providing at least one unobstructed path between the first and second regions of hard tissue. 본 발명은 옆으로 휘어지는 비대칭 임플란트(10)에 관한 것으로, 이 임플란트는 기단부와 말단부(22,24)를 갖고 직선 삽입상태를 취하는 굴곡편을 포함한다. 백본(30)은 굴곡편의 말단부(22)에 연결된다. 완전히 휜 상태에서, 임플란트는 D형과 같은 비대칭 루프(39)를 형성하고, 이 루프는 적어도 일부가 트인 공간(39V)을 이룬다. 굴곡편은 여러 구간들(40,40a~c)이 힌지로 연결된 구간 시퀀스를 포함한다. 굴곡편의 기단부(24)나 백본에 반대방향으로 작용한 종방향 압력 때문에, 백본과 굴곡편의 기단부 사이에 상대적 종방향 운동이 생기고 굴곡편이 백본 반대쪽으로 수평으로 벌어진다. 임플란트는 측면에서 접근해 척추쪄의 전방구역으로 이식되고 뒷쪽으로 전개된다.
