L5-S1 Posterolateral Gutter Fusion Animation

Welcome to this video on L5-S1 Posterolateral Gutter 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 recommended, the Posterolateral Gutter fusion surgical approach used, 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.

Let’s take a closer look.

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 posterolateral 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. 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.