Multilevel spinal fusion surgery involves the removal of the disc and fusion of the spinal bones (vertebrae) with a bone graft to achieve stability of the spinal segment and eliminate motion. Additionally, the facet joints may be fused at the back of the motion segment to further restrict movement within the segment.
Multilevel Spinal Fusion for Low Back Pain
A multilevel spinal fusion surgery involves fusing 2 or more motion segments of the spine to become one single unit. This surgery is designed to improve spinal stability and reduce pain in conditions that cause spinal malalignment or spinal degeneration.
Typically, spine surgeons recommend multilevel spinal fusion when:
- The patient’s quality of life is significantly affected due to lower back pain and functional limitations
- Nonsurgical pain management, such as medication, physical therapy, and injection treatments, have been tried for several months or longer without satisfactory improvement
- A spinal x-ray or magnetic resonance imaging (MRI) scan confirms degenerative changes or malalignment at more than one level
In the lower back, a multilevel spinal fusion surgery involves the fusion of two or more motion segments between the first lumbar vertebra, L1, and the first sacral vertebra, S1.
Interbody in Multilevel Spinal Fusion Surgery
A metal or plastic spacer (interbody cage) is commonly placed into the disc space in addition to the bone graft, in order to maintain the height of the disc during healing.
Lumbar interbody fusion can be accomplished through several approaches, including:
Anterior lumbar interbody fusion
An anterior lumbar interbody fusion (ALIF) surgery is a type of spinal fusion performed to stabilize a painful motion segment in the lower back, commonly caused by lumbar degenerative disc disease and/or spondylolisthesis. The surgical approach is via the front of the abdomen, working around and behind the abdominal contents to access the front of the spine, where the disc is located. ALIF is a common surgical technique used to treat lumbar degenerative disc disease with disc collapse, and spondylolisthesis.
Extreme lumbar interbody fusion
An extreme lumbar interbody fusion (XLIF) approach is used to place a large cage to fill the disc space directly from the side of the disc, through a split in the psoas muscle present alongside the lumbar spine. The incision is on the side of the body, and the approach stays behind all the abdominal organs. It can only be used at the L1-L2, L2-L3, L3-L4, and L4-L5 levels. It is not used at the L5-S1 level due to the position of the pelvis. A slightly anterior modification of this approach is called the oblique lumbar interbody fusion (OLIF).
XLIF surgery may also be referred to as lateral lumbar interbody fusion (LLIF) or direct lateral interbody fusion (DLIF).
Posterior lumbar interbody fusion
Posterior lumbar interbody fusion (PLIF) aims to fuse two levels of the spine by taking a surgical approach from behind the lumbar spine. The nerve sac must be exposed and retracted to make room for smaller cages than can be placed through the anterior or lateral approaches. Conditions treated using this approach include degenerative disc disease with spinal instability, recurrent disc herniation, spondylolisthesis, and spinal stenosis.
Transforaminal lumbar interbody fusion
The transforaminal lumbar interbody fusion (TLIF) technique is used to place an interbody cage via an oblique insertion approach, typically by removing one of the facet joints. A TLIF surgery may be indicated when back and/or leg pain occurs due to spondylolisthesis, degenerative disc disease, recurrent disc herniations, or pseudoarthrosis (the lack of a solid fusion) from prior fusion surgery.
Posterior or Posterolateral Fusion in Multilevel Spinal Fusion Surgery
This approach is done through the back and focuses on connecting portions of the posterior (in the back of the spine) bony elements and facet joints of the spine. This may also be referred to as a facet fusion.
Each type of spinal fusion has specific indications as well as specific risks and benefits, and may be done at more than one level of the spine.
The Role of Spinal Instrumentation in Multilevel Fusion
Most multilevel fusion procedures involve the use of spinal instrumentation in the back of the spine, but may also include supplemental anterior fixation. The role of spine fusion instrumentation is to provide additional spinal stability, acting as an internal brace while the bony fusion heals.
Common surgical implants used in multilevel spine fusion include spinal interbody cages, anterior plates, and posterior pedicle screws and rods, and sometimes hooks and wires.