An intervertebral fusion cage assembly comprising an intervertebral fusion cage and an inserter adapted to be coupled to the intervertebral fusion cage for inserting the cage, in which: the inserter has a rod having smooth upper and lower surfaces (115, 117), upper and lower arms (119, 121) having bevelled distal ends, and a height defined between the upper surface and the lower surface; and the intervertebral fusion cage comprises: a) a leading end (51; 155) having a right and left end, a front surface and a back surface (59; 153), wherein the front surface of the leading end is tapered; b) first and second support members (61, 63) extending backwards from the right and left ends, each member having an upper and lower surface adapted for bearing against adjacent vertebral bodies, and proximal end surfaces, the upper and lower surfaces comprising a plurality of teeth adapted for gripping the adjacent vertebral bodies, the cage having a height defined between peaks of the teeth of the upper surface and peaks of the teeth of the lower surface; and c) an open trailing end formed between the proximal end surfaces of the support members; in which the back surface of the cage is adapted to receive the rod, and in which the height of the inserter is taller than the height of the cage so that, when the inserter is coupled to the cage, the smooth upper and lower surfaces extend proud of the cage teeth. the inserter has a rod having smooth upper and lower surfaces (115, 117), upper and lower arms (119, 121) having bevelled distal ends, and a height defined between the upper surface and the lower surface; and the intervertebral fusion cage comprises: a) a leading end (51; 155) having a right and left end, a front surface and a back surface (59; 153), wherein the front surface of the leading end is tapered; b) first and second support members (61, 63) extending backwards from the right and left ends, each member having an upper and lower surface adapted for bearing against adjacent vertebral bodies, and proximal end surfaces, the upper and lower surfaces comprising a plurality of teeth adapted for gripping the adjacent vertebral bodies, the cage having a height defined between peaks of the teeth of the upper surface and peaks of the teeth of the lower surface; and c) an open trailing end formed between the proximal end surfaces of the support members; a) a leading end (51; 155) having a right and left end, a front surface and a back surface (59; 153), wherein the front surface of the leading end is tapered; b) first and second support members (61, 63) extending backwards from the right and left ends, each member having an upper and lower surface adapted for bearing against adjacent vertebral bodies, and proximal end surfaces, the upper and lower surfaces comprising a plurality of teeth adapted for gripping the adjacent vertebral bodies, the cage having a height defined between peaks of the teeth of the upper surface and peaks of the teeth of the lower surface; and c) an open trailing end formed between the proximal end surfaces of the support members; in which the back surface of the cage is adapted to receive the rod, and in which the height of the inserter is taller than the height of the cage so that, when the inserter is coupled to the cage, the smooth upper and lower surfaces extend proud of the cage teeth.