Spinal Fusion Surgery
Types of Fusion Surgery
All fusion procedures share the same basic principle: stabilizing wobbly vertebrae with screws and spacers. The difference is which direction the surgeon approaches from.
1. Posterior Fusion (PLIF / TLIF) — From the Back
The surgeon makes an incision along the center of your back to reach the spine. This approach allows both decompression (widening the nerve pathway) and fusion to be done through the same incision.
The damaged disc (cushion between vertebrae) is removed, and a spacer (cage) packed with bone graft is inserted into the space. Screws are then placed into the vertebrae on both sides and connected with rods.
PLIF (Posterior Lumbar Interbody Fusion) The spacer is inserted from the back, passing alongside the nerves on both sides. This provides good visibility, but requires more nerve handling, which slightly increases the risk of nerve injury or dural tears.
TLIF (Transforaminal Lumbar Interbody Fusion) The spacer is inserted from one side at an angle. This reduces the amount of nerve handling compared to PLIF. TLIF is also well-suited for minimally invasive techniques.
| Procedure | Approach | Key Feature |
|---|---|---|
| PLIF | Posterior, bilateral | Wide view; more nerve retraction |
| TLIF | Posterior, unilateral | Less nerve handling; easier to do minimally invasively |
2. Lateral Fusion (LLIF / XLIF) — From the Side
The surgeon makes a small incision on your side (the flank area), moves the abdominal organs aside, and reaches the spine from the side.
A relatively large spacer is placed between the vertebrae. Its height helps indirectly widen the nerve pathway from the inside. In most cases, screws are also placed through a separate small incision in the back.
Advantages
- The back muscles are not extensively cut
- Well-suited for correcting sideways curvature (scoliosis) or treating multiple levels
Disadvantages
- The approach passes near nerves going to the legs, which may cause temporary thigh numbness or weakness (this usually improves over time)
- Not suitable for all spinal levels due to the position of the pelvis and blood vessels
3. Anterior Fusion (ALIF) — From the Front
The surgeon makes an incision in the lower abdomen (below the navel) and approaches the spine from the front.
The damaged disc is removed from the front, and a large spacer is placed to restore both the height and curve of the spine. Screws are usually added from the back through a separate incision.
Advantages
- Allows thorough disc removal and placement of a large spacer to restore spinal alignment
- Does not directly touch the back muscles or nerves — sometimes chosen for revision surgery
Disadvantages
- The approach passes near major blood vessels and abdominal organs, carrying unique risks of vascular injury or organ complications
- May not be suitable for patients with certain body types or previous abdominal surgery
How Is the Right Approach Chosen?
Fusion surgery can be performed from the back, the side, or the front. While the approach differs, the goal is always the same: stabilize wobbly vertebrae with screws and spacers to protect the nerve pathway.
Your surgeon will choose the approach based on:
- Which levels are affected
- How much slippage or curvature is present
- Your body type and other medical conditions (heart, lungs, abdominal issues)
- Previous surgeries
- Your goals for quality of life improvement
When the right approach is chosen for the right patient, outcomes are generally favorable regardless of the specific technique — no single approach is clearly superior to the others. You don't need to memorize these names, but understanding the thought process behind the choice may help you feel more confident.