Transfacet pedicle screw

Screws placed directly across the lumbar facet joint into the pedicle of the level below. No rod is needed. Immobilizes only, does not provide any decompression, distraction or fusion. Therefore not intended for use as a stand-alone. Can be placed percutaneously.

see Lumbar transfacet screw fixation.

Placement is optimal for L3–4, L4–5, or L5–1. Difficulty increases in upper lumbar levels. May be used as adjunct to:

1. ALIF

2. LLIF (when lateral plate not used)

3. contralateral to TLIF (pedicle screws could be used on the side of the TLIF, or a spinous process clamp could be used)

4. axial-LIF (Ax-LIF).

A transfacet pedicle screw cannot be used where the facet has been removed (e.g. for a TLIF) or with a pars defect in the upper of the two levels to be fused.

1. placed percutaneously or via an open procedure usually in the prone position

2. approximate skin incision site: a single midline ≈ 1.5 cm vertical incision is used

a) for L5–1 or L4–5: incision at L3 spinous process

b) for L3–4:incision at L2 spinous process

3. use AP & lateral fluoro to guide trajectory

a) APfluoro: lay a guide wire on the patient’s back and orient it to pass through the desired pedicle. Use a skin marker on the patient’s back to mark the guidewire’s trajectory

b) lateral fluoro: initial bony target is the midpoint of the inferior facet of the upper level. The tip of the guidewire should contact the bone directly posterior to the inferior endplate of the upper level