Anterior lumbar interbody fusion (ALIF) is a spine surgery that approaches the spine through the abdomen to remove all or part of a herniated disc from in between two adjacent vertebrae in the lower back (lumbar spine), then fusing the vertebrae on either side of the remaining disc space. It involves the insertion of a bone graft into the disc space to help the vertebrae join together.
ALIF is designed to stop the motion at the symptomatic segment of the spine. Most commonly, this procedure is performed on the L4 through S1 segments at the bottom of the lumbar spine, since these segments are the ones most likely to break down.
An ALIF is the most common treatment for degenerative disc disease and if added stability is needed, may be combined with a posterior approach as well. During the procedure, some type of implant, or cage, is then inserted into the disc space, helping restore more of the normal spacing in between the vertebrae, while alleviating pressure on the nerve roots. Sometimes additional stability is provided by inserting screws through the cage.
Although threaded titanium cages initially were the only spinal implants that were available, there is now an assortment of cages in different shapes, sizes and materials, giving the patient having ALIF surgery more options.
In the months following the surgery, the bone graft heals together through and alongside the cage, creating one long bone between the vertebrae and immobilizing that segment of the spine.