PLIF — Posterior Lumbar Interbody Fusion

PLIF is a fusion in which the disc is removed and replaced with cages placed into the disc space entirely from the back, supported by screws and rods. The key difference from TLIF is the route to the disc. In PLIF, the disc space is reached from both sides of the midline, which means gently retracting the dural sac and the nerve roots towards the middle to make room to clear the disc and insert the cages. Two cages, one on each side, are commonly used, and bone graft is placed so the segment fuses over the following months. It is a powerful, well-established way to place interbody support and restore the front column of the spine.

Because I treat every fusion as a deformity case, my focus in a PLIF is the same as in any interbody: to place the cages so as to rebuild the segmental lordosis and to choose that lordosis to protect the person's overall sagittal balance. PLIF, done well with anteriorly placed and lordotic cages, restores segmental and lumbar lordosis effectively, and bilateral cages with pedicle screws give very high fusion rates. That said, in my own practice the transforaminal route — TLIF — is often my preference for a posterior interbody, because it reaches the same disc space from one side without needing to retract the nerve sac across from both sides, which lowers the risk of dural tears and nerve irritation. So I regard PLIF and TLIF as close cousins that achieve the same fundamental goal — interbody support and restored alignment from the back — with TLIF generally offering a gentler route for the neural structures.

As with TLIF, posterior interbody fusion is increasingly being done through endoscopic approaches, and the principle that appeals to me is the same: low demand, low insult. Working through small portals, sparing the muscles, with less bleeding and a more comfortable recovery, achieves the same interbody goal with far less collateral damage to the tissues. Full-endoscopic and biportal posterior interbody techniques are developing quickly. They carry a learning curve and are not suited to every case, but for the right, lower-demand problem they represent an attractive, tissue-sparing way to achieve the fusion.

PLIF is a well-validated technique with a long track record. Bilateral cages combined with pedicle screw fixation drive fusion rates towards very high levels, and anteriorly placed, lordotic cages improve segmental and lumbar lordosis. Comparative studies and meta-analyses of PLIF against TLIF find broadly similar fusion rates and patient satisfaction, but consistently show that PLIF involves more neural retraction and therefore a higher rate of dural tears and nerve-root irritation, along with somewhat longer operating time and greater blood loss — which is why many surgeons, myself included, often favour the transforaminal route for a posterior interbody. Restoring lordosis reliably, particularly at the lowest levels, remains technique-dependent, which is exactly why cage choice and position receive such attention.

Recovery follows the pattern of posterior interbody fusion generally. Most people are up and moving within a day or so and home within a few days. Heavy lifting and twisting are limited for a period of weeks to months while the fusion becomes solid, with physiotherapy guiding a graded return to activity. The fused level is now stiff because it is joined, while the rest of the spine continues to move — and when the alignment has been restored well, that fused segment sits within a balanced spine. The spine is followed up over the longer term.

• —Posterior lumbar interbody fusion (review). (PMID 18316711)
• —Comparison between PLIF and TLIF for lumbar degenerative diseases: systematic review and meta-analysis. (PMID 29367001)
• —Comparative study of PLIF and TLIF in adult degenerative spondylolisthesis. (PMID 18685873)
• —Comparative study of perioperative complications: TLIF versus PLIF in degenerative spondylolisthesis. (PMID 26126415)
• —Do TLIF and PLIF differ in perioperative complications? Comparison of two high-volume centres. (PMID 38631328)
• —Is one cage enough in PLIF: unilateral single cage versus bilateral cages. (PMID 17285054)
• —Posterior lumbar interbody fusion with cages: an independent review of 71 cases. (PMID 10505503)
• —Effects of lordotic angle of a cage on sagittal alignment in one-level PLIF with pedicle screws. (PMID 25685795 / PMC4317641)
• —Influence of cage geometry on sagittal alignment in instrumented PLIF. (PMID 12897494)
• —Anterior placement of cages in PLIF for good lumbar lordosis. (PMC10853625)
• —Learning curve and initial outcomes of full-endoscopic posterior lumbar interbody fusion. (PMID 35574552 / PMC9096087)
• —Full-endoscopic, biportal, and conventional PLIF comparison. (PMC12537724)