Welcome to this video on L5-S1 spinal fusion.
If you’ve been dealing with persistent low back pain or sciatica that hasn’t improved with non-surgical treatments, your doctor may have recommended a spinal fusion.
In this video, we’ll explain what the L5-S1 segment is, why fusion may be necessary, the surgical approaches used to stabilize this part of the spine and answer common questions patients have about the procedure.
The goal of lumbar fusion is to stop motion at a painful spinal motion segment.
This is achieved by setting up the biological conditions for bone to grow into a bridge connecting two vertebrae.
During the procedure, a bone graft is placed between the vertebrae, and over time, this graft stimulates new bone growth.
As the bone heals, the vertebrae fuse into a single, solid bone, eliminating movement at the segment and reducing pain.
The biological process of bone healing involves several stages.
Initially, when the bone graft is placed, the body responds by forming a blood clot around the graft.
This clot is essential as it provides a scaffold for new cells to migrate into the area.
Over the next few days, specialized cells called osteoblasts begin to form new bone tissue.
This process is known as osteogenesis.
As healing progresses, the body continues to produce new bone cells, gradually replacing the graft material with new bone.
This process can take several months to over a year to fully complete.
Eventually, the two vertebrae become fused together, creating a stable segment that alleviates pain and restores function.
The L5-S1 segment is located at the base of your spine, where the fifth lumbar vertebra (L5) meets the first sacral vertebra (S1).
This segment is a key weight-bearing area of the spine and allows for a wide range of movements like bending and twisting.
The spinal motion segment includes the two L5 and S1 vertebrae, the intervertebral disc in the front, paired facet joints in the back, and nerve roots exiting from the thecal sac, which are all essential for spinal function.
Over time, the L5-S1 segment can become painful due to conditions such as degenerative disc disease, a herniated disc, or spondylolisthesis.
These conditions can lead to chronic pain and/or disability.
When nonsurgical treatments do not provide pain relief or improve function, a spinal fusion may be considered to stabilize the spine and reduce pain.
There are several surgical approaches to perform an L5-S1 fusion.
The three most common are Anterior Lumbar Interbody Fusion (ALIF), Posterolateral Fusion (PLF), and Posterior Lumbar Interbody Fusion (PLIF).
Each approach has its own advantages and disadvantages and is chosen based on factors such as the patient’s diagnosis, overall health, and the surgeon’s experience. Let’s take a closer look at each approach.
ALIF stands for Anterior Lumbar Interbody Fusion.
In this approach, the surgeon accesses the spine through the front of the body.
A 3-to-5-inch horizontal incision is made in the lower abdomen. Here are the main steps of the procedure:
The abdominal muscles and blood vessels are carefully moved aside to expose the spine.
The damaged intervertebral disc is removed.
A bone graft and sometimes an interbody cage is placed into the empty disc space to restore height and alignment.
Fixation devices, such as screws or plates, may be added for stability.
The incision is closed with sutures or staples.
The potential advantages of this procedure is it does not disrupt the lower back muscles, which tends to lead to lower postoperative pain and faster recovery for many patients and placing the bone graft in between the vertebrae can restore disc height and tends to help the fusion set up.
PLF, or Posterolateral Fusion or Posterolateral Gutter Fusion, involves accessing the spine from the back. A 3-to-6-inch incision is made along the midline of the lower back.
The main steps include:
The back muscles are separated to expose the vertebrae.
Bone graft material is placed along the sides of the spine, near the transverse processes in the posterolaterl gutter.
Pedicle screws and rods are inserted to hold the vertebrae in place while the bone graft heals.
The incision is closed with sutures or staples.
This approach has the potential advantage of using rods and screws to provide additional stability for the L5-S1 segment while the fusion is growing into a solid bone.
It may be considered when the additional stability is needed vs. restoring disc height.
PLIF, or Posterior Lumbar Interbody Fusion, involves accessing the spine from the back.
A 3-to-6 inch incision is made along the midline of the lower back.
The main steps include:
The back muscles are separated to expose the vertebrae and the intervertebral disc.
The damaged disc is removed, and the disc space is prepared.
A bone graft and interbody cage is placed into the disc space to restore height and alignment.
Pedicle screws and rods are inserted in the back to stabilize the spine.
The incision is closed with sutures or staples.
This approach allows for both stabilization and restoration of disc height.
A surgeon may also recommend a combination of these approaches in certain cases.
For example, an ALIF and a posterolateral gutter fusion may be done during the same surgical procedure if the goals are to restore the disc height, alignment and more stability for the lower spine.
L5-S1 spinal fusion is a procedure designed to reduce pain and improve stability in the lower back.
All spinal fusion carries potential risks and complications.
It is almost always the patient’s decision to have a fusion or to pursue nonoperative treatments.
If you’re considering this surgery, talk to your doctor about the approach that’s best for you.
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