Unstructured Adaptive (UA) NAS Parallel Benchmark. Version 1.0

An intervertebral fusion device comprises a hollow tubular body, a plurality of stretching elements, an adjustment element, and an urging element. The tubular body is provided peripherally with a plurality of receiving holes in which the stretching elements are disposed movably. The adjustment element is disposed in the hollow interior of the tubular body such that inner ends of the stretching elements are urged by the adjustment element. The urging element is disposed in the hollow interior of the tubular body such that the adjustment element is urged at the top thereof by the bottom of the urging element, and that the adjustment element can be actuated by a rotational motion of the urging element so as to cause the stretching elements to jut out of the receiving holes for bringing about an increase in diameter of the tubular body.