Lateral-PLIF for Lumbar Spinal Arthrodesis: A Detailed Step-By-Step Surgical Technique

We developed a modern way to perform a PLIF technique. So historically, the PLIF was developed in the middle of the last century and became very popular in the 80s and 90s. But due to a neuro-complication concern, the technique was less used by the spine surgeon.

So we try to improve the technique, keeping the main advantages of the PLIF technique, but reducing the limitation. So the concept of the technique is to use a lateral variant of the PLIF technique using a safer corridor. So the idea is to go through the transitional zone between the lateral canal, the intervertebral foramen, and the central canal, so passing through really a safe zone, reducing the risk of a neuro complication, and keeping all the advantage of technique bilateral approach, bilateral decompression, optimal instrumentation.

Here, a step-by-step procedure is presented for a single level L4-L5 lateral PLIF addressing a degenerative L4-L5 grade one spondylolisthesis. To begin, make a standard posterior midline skin incision on the patient centered on the operative level. Incise the lumbar fascia, and carefully expose the posterior bony elements subperiosteally, including the lamina of the two adjacent vertebrae, posterior facets, and pedicular entry zones.

Using an osteotome, perform a subtotal facetectomy by bilaterally resecting the inferior facet of the upper vertebra. Partially remove the superior facet of the lower vertebra, flattening it to facilitate pedicle screw insertion. Now, insert multiaxial pedicle screws at the appropriate levels.

Confirm correct placement using biplanar fluoroscopy or CT-guided navigation. Apply an interlaminar distractor at the base of the spinous processes to improve exposure and enlarge the working space. Resect the midline ligamentous structures while keeping the adjacent spinous processes intact.

Remove the tip and medial part of the superior facet to expose the proximal intervertebral foramen located at the transition zone between the central and lateral canal just above the lateral recess. When necessary, use a Kerrison rongeur to further open the lateral recess and decompress the passing nerve root. If additional central decompression is required, perform partial laminectomy and phlebectomy.

Next, remove the lateral ligamentum flavum and underlying fatty tissue, preserving the fatty tissue surrounding the nerve root to facilitate exposure of the underlying disc space. Once hemostasis is achieved, expose the disc between the dural sac medially and the foraminal root laterally with minimal or no retraction of neurological structures. Now, create a rectangular window in the annulus using a scalpel blade, positioning it in the transitional zone between the lateral part of the central canal and the medial part of the intervertebral foramen.

Use a nerve root retractor to protect the dural sac, applying only limited retraction. Then use specialized straight and angled osteotomes, pituitary Rodgers rasps, and curettes to elevate and remove disc material. Apply intervertebral distraction on one side, starting at six to seven millimeters.

Gradually increase to 11 to 12 millimeters, allowing safe and controlled discectomy on the contralateral side. Remove the cartilaginous layer until the bony endplate of the adjacent cranial and caudal vertebrae is clearly exposed to complete endplate preparation. Next, pack the anterior disc space and both cages with bone graft using either local bone or bone substitutes depending on the clinical situation.

Insert the two cages into the interbody space and advance them using a straight impactor. Confirm the correct placement of cages, pedicle screws, and rods using planar fluoroscopy. A representative case of L4-L5 degenerative spondylolisthesis with severe canal stenosis successfully treated with a L4-L5 lateral PLIF is presented here.

Postoperative computed tomography imaging confirmed successful bilateral cage placement with restored anatomical alignment at the L4-L5 level, following lateral PLIF along with complete neural decompression of the spinal canal. The PLIF method accessed the disc via the central canal. The TLIF method utilized a more lateral trajectory through the foramen and the lateral PLIF trajectory allowed for direct access to the disc space while avoiding both the central canal and neuroforamen.

The final position of the interbody cages in lateral PLIF was symmetrical across the midline, and graft material was densely packed around and within the cages to support fusion. To summarize, if we compare with the other techniques, so the historic PLIF go through the central canal with high risk regarding the neurostructures. The TLIF go through the foramen with risk regarding the foraminal root.

So it's a nice way to go between and safer regarding the neurostructures. If we compare with the current, which is the TLIF, which typically is performed using a unilateral approach, I would say the advantages of lateral PLIF are the bilateral approach, placing two cages with a greater stability, the opportunity to perform distraction from the disc space one side when placing the cage contralaterally on the other side, permitting to place optimal size cages. And finally, compared to the historic PLIF, it's, of course, less invasive.

No need for complete laminectomy, passing more lateral, safer regarding the neurological structures. So at the end, the technique is optimal regarding all the objective of the fusion in terms of clinical outcome, high rates of fusion, and safe regarding the neurostructures. So regarding our experience the last year, so we shift from TLIF to lateral PLIF.

We are more confident with the technique. We are satisfied by the two kgs placement, optimal graft surface, the bilateral approach. And we consider that for the next future, it will be our standard to perform a lumbar fusion.