Spinal Fusion: Posterior Lumbar

Spinal Fusion: Posterior Lumbar

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Spinal Fusion: Posterior Lumbar

Image of lumbar vertebrae

Fusing vertebrae in the lumbar spine may help ease lower back and leg pain. Posterior lumbar fusion is done through an incision in your back. The graft is put between the vertebrae in one of two places: in the disk space or between the transverse processes. Depending on how many vertebrae are fused, the surgery may take from 3 to 8 hours.

Bone graft is used to fuse the vertebrae.

Fusing the transverse processes

This process involves several steps:

  • Bone graft is packed between the transverse processes (“wings”) on the sides of the vertebrae. Occasionally, other nearby parts of the vertebrae are fused as well.

  • To help keep your spine steady and promote fusion, extra support (see below) may be used.

  • The incision is closed with sutures or staples.

The image shows bone graft.

The image shows fused bone.

Fusing the disk space

This involves the following:

  • A midline incision is done over your spine, or two incisions on each side of your spine.  

  • The disk between the vertebrae is removed.

  • Bone graft is packed in the now-empty space between the vertebrae. In time, the graft and the bone around it grow into a solid unit.

  • To help keep your spine steady and promote fusion, extra support may be used.

  • The incision is then closed with sutures or staples.

If extra support is needed

Metal supports called instrumentation may be used to help steady your spine while it fuses:

  • A cage may be used when fusing the disk space. This is a plastic or metal “basket” that is packed with bone graft or stem cells. It’s inserted into the empty space where the disk was removed. The cage remains in the body and is not removed.

  • Screws and rods may be used in both types of fusions. In rare cases, these supports may be removed after fusion is complete. Occasionally, absorbable screws and rods are placed and will dissolve after approximately two years.