Interbody Fusion Overview
Indications for Fusion
Lumbar interbody fusion is a surgical technique that attempts to eliminate instability in the back. Instability can be due to degenerated discs and/or facet joints that cause unnatural motion and pain, loss of height of the disc space between the vertebrae that cause pinching of the spinal nerves exiting the spinal canal (foraminal stenosis), slippage of one vertebra over another (listhesis), and/or change in the normal curvature of the spine (scoliosis, hyper- or hypo-lordosis). Discuss with your physician the underlying condition of your spine and the reasons he or she believes fusion will be helpful in your particular case.
How fusion is Performed
Fusion is accomplished by fusing the vertebrae together to reduce their motion. Fusing the vertebrae together requires the removal of most the intervertebral disc (or discs if more than one level is identified for fusion), preparation of the adjacent ends of the vertebrae (endplates) to clear the soft tissue, implantation of an intervertebral spacer to restore the disc height and spinal alignment (for nerve root decompression) and carry the loads of the torso, and packing with bone-forming cells that will bridge the space and fuse the joint.
In some cases, the instability is severe enough that further augmentation of the fusion is required by placing screws and plates or rods into the vertebrae to hold them fixed together.
In most cases, some attempt is made at conservative treatment before fusion is recommended. You have received this booklet because you and your physician have determined that fusion is your best treatment option and have discussed the risk and benefits of surgical versus conservative options. However, there are several techniques for approaching the spine to perform the fusion, defined mainly by the direction of the approach.
The XLIF® procedure was developed to overcome the obstacles of both anterior and posterior approaches, and to access the spine for fusion as minimally disruptive as possible. To help you understand the differences among procedures, three traditional surgical approaches are briefly described.
- Posterior Lumbar Interbody Fusion (PLIF)
In a PLIF procedure, the spine is approached from the back of the body, allowing for direct access to problematic nerves and potential placement of screws and rods in additi
The muscles lying over the spine are opened and spread from the middle out to both sides and some vertebral bone is removed, relieving pressure on the nerves and providing access to the intervertebral disc.
Traditionally, this approach requires significant muscle, bone and ligament dissection and/or disruption, which can sometimes lead to pain and desensitization of the back muscles after surgery.
- Transformational Lumbar Interbody Fusion (TLIF)
A traditional TLIF procedure is essentially a modification of a PLIF procedure where the muscle is dissected from the middle out to the side, but only on one side instead of from the middle out to both sides such as in a PLIF, sparing trauma to the opposite side.
The muscle disruption of the PLIF and TLIF approaches can also be minimized through less invasive techniques using NuVasive® MAS procedures. Ask your surgeon for details.
- Anterior Lumbar Interbody Fusion (ALIF)
In an ALIF procedure, the spine is approached from the front of the body. Spine surgeons and general surgeons often work together to safely expose the front of the spine either by going through the abdomen or by retracting it under the skin.
This approach spares trauma to the back muscles, but requires delicate manipulation of major blood vessels that lie in front of the spine.