Atlas of Pain Medicine Procedures 1st Edition

SECTION III

SPINAL INTERVENTIONS

CHAPTER 30

Percutaneous Facet Fusion

Rinoo V. Shah

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 opens up the inferior recess and the joint; whereas extension opens the superior recess.
• The joint receives a rich sensory innervation by the ipsilateral medial branches, at that level and the cephalad level.
• As the disc degeneration progresses, the facet joint may become lax and facilitate the degenerative cascade.
• Facet arthropathy or sclerosis can be diagnosed and rated, in terms of severity, via MRI and CT scanning. CT or MR imaging provides information about facet orientation and this helps with procedure planning.
• There is a well-established discordance between facet arthropathy and facet mediated pain; hence, the interventional pain community relies on comparative diagnostic blocks to diagnose facet mediated pain. This step may be essential as a prelude to neurolysis, but is not de rigueur for PFF.
• The surgical literature relies on imaging evidence of facet arthropathy and the presence of pain, when planning facet fusion procedures.

What is PFF?

• Percutaneous facet fusion involves the insertion of cortical bone allograft in the shape of a dowel to achieve arthrodesis.
• These dowels are FDA approved as a bone graft to provide stability for primary and secondary healing of bone.
• The dowels have different proprietary designs ranging from cylindrical, tapered, threaded, or rectangular with wings/flanges.
• Different shapes exist to facilitate intra-articular placement and to mitigate “back out” or dislodgement.
• The dowels separate joint surfaces and eventually, stabilize the joint. Surgical access is similar among different manufacturers.

PREOPERATIVE CONSIDERATIONS

• Patients should have constant pain >6/10 and functional limitations.
• Patients should have withheld coagulopathic medications for appropriate lengths of time as per ASRA recommendations.
• Diabetic patients may need blood sugar testing.
• Female patients of childbearing age should have urine pregnancy test or a serum pregnancy test.
• Intravenous access is advised, particularly for patients receiving cervical or thoracic procedures, and for patients who may need intravenous anxiolytics and/or analgesics.
• Cardiopulmonary safe guards and resuscitation equipment should be present within the procedure suite.
• Patients should sign witnessed informed consent, which includes an evidence-based discussion about indications, efficacy, and safety.
• Preprocedure site marking/initialing with an indelible marker site and site verification.

Positioning of the Patient

• Prone
• Pressure points should be padded
• Eye protection may be necessary
• Neck position should be neutral
• Reduce lumbar lordosis

Needles, Medications, and Equipment

• Scalpel, #11 or #15
• 22-gauge spinal needle, 6 in
• Steinman or guide pin ×2
• Cannulated facet distractor (spatula) or directional cannula with prongs ×2
• Drill guide
• Drill bit with electrically powered drill
• Bone dowel delivery device and bone dowels ×2
• Impaction pin ×2

INTRAOPERATIVE TECHNICAL STEPS

• Sterile patient preparation.
• Antibiotic prophylaxis.
• Fluoroscopy to visualize lucency of facet joint.

Oblique angulation (30-50 degrees)—to visualize facet joint lucency.

Angle of approach can be estimated via axial CT or MRI images.

Tip: facet joint may be curvilinear in shape—so obliquity of C-arm should accommodate dorsal limb of facet joint.

• Under fluoroscopy, advance 22-gauge spinal needle is placed into facet joint.
• Make a stab incision with scalpel, adjacent to needle entry site.
• Advance guide (Steinman) pin into plane of facet joint (Figure 30-1).

Figure 30-1. Steinman pin placement, right L5-S1 facet joint.

Tip: use needle path to guide trajectory.

• Once guide pin contacts dorsal surface of facet joint, advance 5 mm.

Tip: the curvature of facet joint should reduce risk of foraminal trespass, but this is not applicable to patients with osteoporosis.

• Advance cannulated facet distractor (Figure 30-2) over guide pin.

Figure 30-2. Cannulated facet distractor, right L5-S1 facet joint.

Tip: anchor guide pin and facet distractor when it enters skin, do not move this aggressively, else it may dislodge out of facet joint.

• Tap facet distractor (spatula) (Figure 30-2) slightly into facet joint with mallet.

Tapered tip facet distractor should stop at 5 mm depth.

Tip: carefully monitor guide pin depth to avoid foraminal trespass.

• Directional cannula should be threaded over facet distractor.
• Place tip of directional cannula (2 prongs) into plane of facet joint.
• Tap the directional cannula to fully seat the device.
• Hold directional cannula and slowly remove the facet distractor and guide pin.
• Advance drill guide into directional cannula.
• Advance drill bit into cannula/drill guide.
• Use drill to core out hole in facet joint.

Tip: Trufuse uses a 1 step drill guide.

• Drill cores out superior and inferior facet joints simultaneously.

Tip: Verteloc uses a 2-step drill guide.

• Drill cores out superior facet (lateral articulating surface).
• Rotate the drill guide 180 degrees.
• Reinsert drill and core out the inferior facet (medial articulating surface).
• The drill guide has a built in stop.

Tip: saline irrigation reduces risk of thermal injury.

Tip: use lateral fluoroscopy to ensure no violation of foramen.

• Remove drill.
• Load implant holder with bone dowel or preformed dowel.
• Implant/dowel is a cortical allograft.

Tip: verify with device manufacturer about safety and reliability of cortical allograft.

Tip: implant holder has different configurations depending on shape of bone dowel.

• Verteloc: rectangular dowel with “fins”—fins are parallel to joint and body is perpendicular.
• Trufuse: cylindrical bone dowel (Figures 30-3and 30-4).

Figure 30-3. Bone dowel, left L5-S1 facet joint.

Figure 30-4. Bone dowel, right L5-S1 facet joint.

• Nufix: threaded bone dowel.
• Advance implant holder with implant into facet joint.
• Tamp dowel into place.
• Remove instruments.
• Suture skin with 2-0 and 3-0 nylon.
• Patient bracing with a lumbosacral orthosis, for 6 to 12 weeks.

MONITORING OF POTENTIAL POSTPROCEDURE COMPLICATIONS

• Assess for bleeding at skin entry site.
• Use lateral fluoroscopy to monitor for foraminal trespass.
• Use anteroposterior fluoroscopy to gauge anteromedial dowel placement.
• Postoperative neurologic assessment

If patient sedated, test withdrawal response on plantar surface of foot

Assess sensorimotor and reflex integrity

Voiding and ambulation status on discharge

CT scan in selected patients (Figures 30-5 through 30-7)

Figure 30-5. Axial CT scan; seated dowels at L5-S1.

Figure 30-6. Sagittal CT scan: seated dowels at L4-5 and L5-S1.

Figure 30-7. (A) 3D CT Scan of TruFUSE, (B) TruFUSE^® Implanted in a sawbone. (Reproduced with permission from Contempo Medical, LLC.)

OUTCOMES

In an abstract presentation, Trangco-Evans demonstrated that 3 out of 8 patients did well and that 5 patients did improve. The latter 5 patients had evidence of dowel back out and poor compliance with postoperative brace utilization. Advances in dowel configuration and improving patient compliance with brace utilization are reasonable goals to improve efficacy.

Patient safety should be monitored in the early postoperative period. Physician vigilance over infection, pain, bleeding, dowel back out, brace compliance, nerve protection, and fall prevention are important.

ACRONYMS

CLBP chronic or nonspecific low back pain

CT computed tomography scan

MRI magnetic resonance imaging

PFF percutaneous facet fusion

Suggested Reading

Boswell MV, Shah RV, Everett CR, et al. Interventional techniques in the management of chronic spinal pain: evidence-based practice guidelines. Pain Physician. 2005 Jan;8(1):1-47.

Fairbank J, Frost H, Wilson-MacDonald J, Yu LM, Barker K, Collins R. Spine Stabilisation Trial Group. Randomised controlled trial to compare surgical stabilisation of the lumbar spine with an intensive rehabilitation programme for patients with chronic low back pain: the MRC spine stabilisation trial. BMJ. 2005 May 28;330(7502):1233. Epub 2005 May 23. Erratum in: BMJ.2005 Jun 25;330(7506):1485.

Fritzell P, Hägg O, Wessberg P, Nordwall A. Swedish Lumbar Spine Study Group. Chronic low back pain and fusion: a comparison of three surgical techniques: a prospective multicenter randomized study from the Swedish lumbar spine study group. Spine (Phila Pa 1976). 2002 Jun 1;27(11):1131-1141.

Fritzell P, Hägg O, Wessberg P, Nordwall A; Swedish Lumbar Spine Study Group. 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine (Phila Pa 1976). 2001 Dec 1;26(23):2521-2532; discussion 2532-2534.

Manchikanti L, Helm S, Singh V, et al; ASIPP An ALGOic approach for clinical management of chronic spinal pain. Pain Physician. 2009 Jul-Aug;12(4):E225-E264.

McDonald M, Cooper R, Wang MY. Use of computed tomography-single-photon emission computed tomography fusion for diagnosing painful facet arthropathy. Technical note. Neurosurg Focus. 2007 Jan 15;22(1):E2.

Park YK, Kim JH, Oh JI, Kwon TH, Chung HS, Lee KC. Facet fusion in the lumbosacral spine: a 2-year follow-up study. Neurosurgery. 2002 Jul;51(1):88-95; discussion 95-96.

Raj PP, Shah RV, Kaye AD, Denaro S, Hoover JM. Bleeding risk in interventional pain practice: assessment, management, and review of the literature. Pain Physician. 2004 Jan;7(1):3-51.

Shah RV. Spine pain classification: a solution. Pain Physician. 2013 Mar-Apr;16(2):E51-E59.

Shah RV. The problem with diagnostic selective nerve root blocks. Spine (Phila Pa 1976). 2012 Nov 15;37(24):1991-1993.

Shah RV, Ericksen JJ, Lacerte M. Interventions in chronic pain management. 2. New frontiers: invasive nonsurgical interventions. Arch Phys Med Rehabil. 2003 Mar;84(3)(suppl 1):S39-S44.

Shah RV, Everett CR, McKenzie-Brown AM, Sehgal N. Discography as a diagnostic test for spinal pain: a systematic and narrative review. Pain Physician. 2005 Apr;8(2):187-209.

Shah RV, Kaye AD. Evolving concepts in the understanding of cervical facet joint pain. Pain Physician. 2004 Jul;7(3):295-299. Comment on: Pain Physician. 2004 Jul;7(3):301-309. PMID: 16858465.

Shah RV, Kaye AD. Bleeding risk and interventional pain management. Curr Opin Anaesthesiol. 2008 Aug;21(4):433-438. Review.

Shah RV, Lutz GE. Lumbar intraspinal synovial cysts: conservative management and review of the world’s literature. Spine J. 2003 Nov-Dec;3(6):479-488. Review. PMID: 14609693.

Shah RV, Merritt W, Collins D, Racz GB. Targeting the spinal nerve via a double-needle, transforaminal approach in failed back surgery syndrome: demonstration of a technique. Pain Physician. 2004 Jan;7(1):93-97.

Stein M, Elliott D, Glen J, Morava-Protzner I. Young Investigator Award. Percutaneous facet joint fusion: preliminary experience. J Vasc Interv Radiol. 1993 Jan-Feb;4(1):69-74.

Stieber J, Quirno M, Cunningham M, Errico TJ, Bendo JA. The reliability of computed tomography and magnetic resonance imaging grading of lumbar facet arthropathy in total disc replacement patients.Spine (Phila Pa 1976). 2009 Nov 1;34(23):E833-E840.

Trangco-Evans RA, Bejjani FJ, Shah R, Hassan SE. TruFuse Facet Fusion Outcome: a retrospective case series. Poster 265Presented at the 2011 AAPM Annual Meeting.http://www.painmed.org/library/posters/poster-265.

Wilson-MacDonald J, Fairbank J, Frost H, et al. The MRC spine stabilization trial: surgical methods, outcomes, costs, and complications of surgical stabilization. Spine stabilization trial group. Spine (Phila Pa 1976). 2008 Oct 1;33(21):2334-2340.