Open Transforaminal Lumbar Interbody Fusion

Illustrative Case

A-54-year-old woman status post L4-S1 fusion done elsewhere. Now presents with severe low back pain, bilateral leg pain, and difficulty standing upright. Lateral x-ray demonstrates spondylolisthesis L3-4 and L2-3 above a prior L4-S1 fusion (Figure 22-1). Note the patient has a hyperlordotic L1-2 disk in an attempt to improve sagittal balance. MRI (not shown) demonstrates spinal stenosis at L2-3 and L3-4.

Figure 22-1 ▪ Lateral x-ray demonstrates spondylolisthesis at L3-4 and L2-3 above a prior L4-S1 fusion.

Radiologic Assessment

On radiographs
- Assess the disk height at the level to be instrumented as a guide to the size of the cage.
- In the setting of scoliosis, consider whether to insert the cage on the concavity to improve the alignment or convexity for ease of insertion.
- Assess bone quality. Severe osteoporosis is a relative contraindication to transforaminal lumbar interbody fusion (TLIF) because of the likelihood of substantial graft settling.
On axial and sagittal MRI images:
- Evaluate the position of the exiting root on the operative level on the parasagittal images to determine where it will cross the disk during cage insertion.
- Evaluate for the presence of conjoined nerve roots, which can limit root mobility and potentially prevent cage insertion on that side.

Positioning

The patient is placed prone on a radiolucent Jackson frame, generally with lordosis optimized. Please refer to the chapter on Posterior Lumbar Fusion and Pedicle Screw Instrumentation for details of patient positioning.

Anesthesia and Neuromonitoring Concerns

None specific to TLIF
- We do not routinely use neuromonitoring for posterior spinal decompression and fusion below the level of the spinal cord, with the exception of surgery involving deformity correction (scoliosis, kyphosis).

Localization of Incision

Needle localization x-ray is performed as noted in the chapter on Posterior Lumbar Fusion and Pedicle Screw Instrumentation.

Approach

Standard posterior midline approach is utilized.

Decompression Technique

Please refer the Lumbar Laminectomy chapter for central and lateral recess decompression technique.
The details of complete unilateral facetectomy required for a TLIF are given below.

Instrumentation/Fusion Technique

Complete Unilateral Facetectomy

After exposure and laminectomy, the next step is to perform a complete unilateral facetectomy. We choose the side of facetectomy based on the laterality of patients’ symptoms or severity of stenosis or based on rotation and scoliosis of the spine.
After midline laminectomy, the pars and inferior articular process are removed.

The superior articular process of the caudal vertebra is then removed using Kerrison rongeurs, down to the cephalad aspect of the pedicle, such that the top of the pedicle can be seen and palpated (Figure 22-2). This allows for maximal access to the disk space.

Figure 22-2 ▪ A thorough laminectomy to decompress the canal has been completed, along with total facetectomy on the side of the planned interbody fusion. It is important to remove all of the superior facet down to the superior aspect of the caudal pedicle, in order to maximize the working space for insertion of the cage. This creates a triangular working portal for interbody fusion.

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