Posterior Lumbar Interbody Fusion Surgery (PLIF)

What is PLIF Surgery?

Posterior Lumbar Interbody Fusion (PLIF) is a lumbar spinal fusion procedure performed entirely through the back (posterior approach). The intervertebral disc is accessed centrally by retracting the nerve roots on both sides, allowing insertion of two interbody cages — one on each side of the disc space — combined with pedicle screw and rod fixation to stabilise the fused segment.

PLIF was one of the first interbody fusion techniques developed and has a long track record of clinical success. It provides simultaneous nerve decompression and interbody fusion through a single posterior incision, and is performed using minimally invasive techniques at One Brain and Spine in Melbourne.

When is PLIF Recommended?

• Lumbar instability, spondylolisthesis, or degenerative disc disease requiring stabilisation
• Recurrent disc herniation requiring fusion
• Spinal stenosis with instability requiring simultaneous decompression and fusion
• When bilateral central decompression at the disc level is required

What Happens During PLIF?

The procedure is performed under general anaesthesia with the patient prone (lying face down). Through a midline posterior incision, the spinal muscles are retracted to expose the laminae (bony covering over the nerves) and facet joints. A bilateral laminectomy or laminotomy is performed to access the spinal canal. Both nerve roots are gently retracted medially, exposing the disc space centrally. The intervertebral disc is removed from both sides, and two interbody cages are inserted — one from each side — into the prepared disc space with bone graft.

Percutaneous pedicle screws are then placed bilaterally using navigation and/or robotics and connected with rods to provide rigid stabilisation of the fused level. Intraoperative navigation and neuromonitoring are used routinely. The procedure takes approximately 2 to 4 hours. Hospital stay is 2 to 5 days.

PLIF vs TLIF

Both achieve identical spinal fusion goals. TLIF uses a unilateral transforaminal approach (one side only), requiring less nerve root retraction and generally associated with lower nerve injury risk. PLIF uses a bilateral central approach, allowing direct bilateral neural decompression. The choice between PLIF and TLIF depends on the specific anatomy and surgical requirements at each level.

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Outcomes of PLIF

PLIF achieves fusion rates of 85–95% at 12 months with modern techniques. The large majority of patients achieve significant relief of leg pain and improved function. Back pain improvement is less predictable. Long-term follow-up data supports PLIF as a durable lumbar fusion technique.

Risks and Complications

General Surgical Risks

• Wound infection — approximately 1–2%; higher for multilevel procedures
• Bleeding — intraoperatively or postoperatively; rarely requires return to theatre
• CSF leak — approximately 1–2%

Fusion-Specific Risks

• Non-union (pseudarthrosis) — failure of the bone to fuse in 5%; more common in smokers, multi-level surgery, and poor bone quality; may require revision surgery
• Adjacent segment disease — accelerated degeneration at levels above or below the fusion
• Nerve injury — persistent or worsening leg pain, numbness, or weakness
• Implant malposition or failure — minimised by intraoperative navigation
• Persistent back pain — fusion does not guarantee resolution of back pain
• Bowel or bladder dysfunction — rare

PLIF-Specific Risk

• Nerve root injury — slightly higher theoretical risk than TLIF due to bilateral nerve root retraction; minimised by gentle technique and intraoperative neuromonitoring