Chapter 30: Percutaneous Facet Fusion

BACKGROUND

As surgical technology becomes less invasive, interventional pain physicians will play an increasing role in delivering this care. Facet mediated pain has historically been treated with medial branch blocks, intra-articular injections, and radiofrequency neurolysis. There has been an increased interest in treating facet mediated pain from a surgical standpoint. Since facet joints are synovial diarthrodial joints, surgical approaches have focused on joint immobilization or arthrodesis. One minimally invasive approach is percutaneous facet fusion (PFF) with allograft bone dowels.

INTRODUCTION

PFF has emerged as a standalone and augmentative procedure to help patients with facet mediated pain. The procedure addresses facet mediated pain due to degenerative facet arthrosis, mechanical loading, and minor instability.

The advantages of PFF are:

• Reduced invasiveness and morbidity

• Early recovery and discharge

• Motion preservation

PFF fits well within the continuum of spinal care, with a position between interventional (percutaneous) and reconstructive (surgical) spinal procedure.

PFF doesn’t “burn bridges.”

• The current patients will still have access to future advances in spinal surgery, eg, biologics.

• Technical feasibility, safety, and biomechanical stability have been demonstrated.

• Percutaneous facet fixation with screws and intra-articular facet joint spacers have demonstrated efficacy.

• Finally, less invasive fusions have comparable outcomes to more invasive fusions and patient selection continues to be subjective.

POTENTIAL INDICATIONS

• Isolated facet–based symptomatic back pain that is refractory to conservative measures

• Stabilization of the lumbar spine following decompressive procedures or where minor instability exists or presents postoperatively

• Minor instability (1-2 mm listhesis)

• Posterior supplemental fixation to interbody fusion

• Adjunct to motion limiting devices

CONTRAINDICATIONS (RELATIVE OR ABSOLUTE) AND INDICATIONS FOR PROCEDURE TERMINATION

• Trauma

• High-grade instability

• Tumors

• Spondylolysis (pars fracture)

• Grade 2 or greater spondylolisthesis

• Infection, systemic or localized

• Coagulopathy

• Distorted or complicated anatomy

• Progressive neurologic deficit

• Allergy to procedural drugs, eg, iodinated contrast

• Open wound or skin ulceration

• Poorly controlled diabetes

• Patient refusal or lack of health care proxy

• Inability to prone for the duration of the procedure

• Intraoperative recognition of foraminal trespass or epidural placement

• Severe nerve root pain during procedure

• Hypotension

RELEVANT ANATOMY

• The lumbar facet joint is a diarthrodial, synovial joint. These joints can undergo a process of degeneration leading to arthropathy.

• The facet joint represents an articulation between the inferior articular process of the cephalad vertebral body and the superior articular process of the caudal vertebral body.

• The inferior articular process is convex and the superior articular process is concave.

• The joint is oriented obliquely to the sagittal plane.

• The articular surfaces are lined with hyaline cartilage.

• The joint contains a synovial membrane and synovial fluid. The joint is encapsulated with a synovial sheath. This creates a superior articular recess that is anterior and an inferior articular recess that is posterior.

• Forward flexion ...