ALIF — anterior lumbar interbody fusion

Yes: the disc is reached from the front without opening the peritoneum, the sac that wraps the bowel, working in the plane that lies in front of it. The back is not touched at any point, so no scar is left on it.

Because from the front the whole disc can be removed and a large-footprint implant placed, restoring disc height and the lordosis of the segment, which is especially valuable at the lowest levels, L4-L5 and L5-S1. And as the posterior elements are not touched, the structures that provide stability stay intact.

Lordosis is the natural inward curve of the lower back, and it is what allows the head to line up over the pelvis so that standing upright costs no effort. When a disc collapses, that segment loses curve; giving it back is not a cosmetic detail, it is what keeps the whole column balanced.

The prosthesis is implanted through this same anterior approach, but instead of fusing the segment it keeps it moving. Its conditions are far stricter — healthy facet joints, good bone quality, no deformity or instability — so the two are not interchangeable: the choice follows what the spine allows.