A spinal fusion is the permanent joining of two or more vertebrae so that there is no movement between them. Over time they heal into a single, solid bone. The procedure involves roughening the bone between two adjacent vertebrae and then placing bone graft between them. In some cases, disc material may be replaced with donated bone, or in the case of degenerative disc disease with or without Grade 1 spondylolisthesis, plastic or metal spacers may be used instead. Rods and screws are then placed to create an “internal cast” that support the vertebrae, holding it together until the fusion, or bony regrowth, can occur.
Spine surgery involves creating a single incision and stripping the muscles from the spine. In comparison to a minimally invasive technique, the “open” method offers key benefits that include:
- Increased access to the spine to remove the damaged bone or intervertebral discs with less likelihood of leaving compressive elements behind
- Greater visibility to the surgeon in order to place the rods, screws, and bone graft materials needed to stabilize the spinal bones, and hence create less risk of damage to nerves or surrounding structures.
When surgeons replace disc material with either bone, plastic, or metal spacers, they may approach the disc space in different ways:
- Anterior lumbar interbody fusion (ALIF) – An incision is made in the abdomen
- Posterior lumbar interbody fusion (PLIF) – An incision is made in the back
- Transforaminal lumbar interbody fusion (TLIF) – An incision is made in the back next to the spine to access the vertebra at an angle
- Direct lateral interbody fusion (DLIF) – An incision is made on the side of the abdomen
All these procedures can also be done using a minimally invasive technique, and all involve joining different parts of two or more vertebrae together. Your surgeon will decide on the best approach after considering various factors, including the spinal condition to be treated, its location in the spinal column, and your overall health.