Download Radiofrequency Ablation 101

Radiofrequency Ablation 101
Neuroscience Summit
September 10, 2016
Chris Pratt, DO
Texas Health Care Pain Management
1651 West Rosedale Street, Suite #205 Fort Worth, Texas 71604
What’s in a name?
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Radiofrequency Ablation
RFA
Rhizotomy
Neurotomy
Rhizotomy
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Interventional pain modality designed to decrease the
sensation of pain by denervating the source
Provides partial relief
Provides temporary relief/can be repeated
Common Applications
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Lumbar facet pain
Cervical facet pain
Thoracic facet pain
Sacroiliac joint pain
Less Common Applications
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Regional neuropathic pain syndromes
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Sympathectomy
Ganglion lesion
Nociceptive pain syndromes
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Knee
Hip
Heel
Facet Syndrome Diagnosis
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Axial pain without a distinct radicular pattern (facet
pain can have referred components ie. HA’s
arm/shoulder buttock/leg)
Pain may be relieved by standing, walking, rest or
repetitive activity
Tenderness over affected facet joints
Pain is worse with extension
Pain is relieved with flexion
Imaging may show severe facet degenerative disease,
or may be relatively normal
Case Study
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Patient LR is a 68 year old male
5 year history of intermittent low back pain
Pain has become constant over the last 8 months
Pain is bilateral but worse on the right (VAS 6/10)
Has tried OTC NSAIDS, occasional narcotics with only short
term relief
PT, felt short term relief with each session but worse the
next day
MRI- degenerative disc L5-S1, minimal spondylolisthesis L45, facet arthopathy L3-S1 with subchondral cyst L5-S1, no
central stenosis
Conservative Treatment
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Duration 6-8 weeks to give the pain a chance to go
away
Therapy, formal and home based
Medications, steroids, NSAIDS, narcotics
Ice/Heat avoidance of aggravating factors
Imaging, rule out surgical indication, fracture,
malignancy
RF and Treatment Modality
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Facet related pain must be meticulously established
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At least 2 diagnostic procedures
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Intra-articular facet injection
Medial branch blocks
Placebo injection
Comparative blocks with short- and long-acting anesthetics
Relief of the pain should be “significant” and
consistent with the duration of the anesthetic used
Case Study
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Patient RL having failed conservative treatment
underwent a lumbar facet injection B/L L3-S1
Reported 70% pain relief that lasted 4-6 weeks, but
was only 30% improved at his 2 month follow up
Lumbar medial branch block was performed L2,3,4,5
Reported 80% relief of his back pain the day of the
injection with a precipitous return of the pain over the
next 2-3 days
Lets Cook
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RL was offered RFA of the medial branch L2,3,4,
dorsal ramus L5
Alterative treatments were discussed
Risks: bleeding infection, unintentional damage to
nerves, increased postoperative pain
Expectations: increased pain for 2-5 days followed by
a 60% reduction of the usual pain for 8-14 months
Facet Denervation
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Destruction of the nerve supply to the facets
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Medial branches C3-L4
Third occipital nerve
Posterior primary ramus of L5
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C8 spinal nerve changes everything
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Dual nerve supply
Proper nomenclature
Landmarks
MB = medial branch
TON = 3rd occipital nerve
LB = lateral branch
SAB = superior articular branch
NR = nerve root
TP = transverse process
VA = vertebral artery
IC = iliac crest
DPR = dorsal primary ramus
IAB = inferior articular branch
RF and Patient Selection
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Pain relief in the expected distribution of the injected
facet joint/MBB
Similar relief from at least 2 diagnostic injections
Aggressive non-surgical therapy has failed
Patient with realistic goals
Psychosocial factors have been addressed
Equipment
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Radiofrequency generator (Thermal and/or Pulsed)
Grounding pad and connecting cable
Electrodes and disposable needles
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5cm, 10cm, 15cm needles (5 or 10mm active tips)
18-22 gauge insulated needles
Dependent on location and patient body habitus
Straight vs. curved needles
22 gauge, 3.5” spinal needle for deep local
Lead apron and thyroid shield
Fluoroscopy (c-arm, image archiving)
Sterile scrub
Preparation for Procedure
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Fluoroscopically assess anatomy
Anatomy and nerve nomenclature
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2 nerves, 1 facet joint
T12-L4 MB-base of transverse process and SAP
L5 medial branch-sacral ala groove and S1 SAP
MB arises over transverse process above and below
the joint
Lumbar PA and Lumbar Oblique
MB = medial branch
IC = iliac crest
IAB = inferior articular branch
NR = nerve root
LB = lateral branch
TP = transverse process
IBP = intermediate branch
plexus
DPR = dorsal primary ramus
S = superior articular process
FJ = facet joint
SAB = superior articular branch
I = inferior articular process
Images from Fenton, DS, Czervionke LF. Image-Guided Spine Intervention. WB Saunders, 2003.
Oblique Lumbar Spine Target for Needle Placement
Images from Fenton, DS, Czervionke LF. Image-Guided Spine Intervention. WB Saunders, 2003.
Scotty Dog
SAP = superior articular process
IAP = inferior articular process
FJ = facet joint
Images from Fenton, DS, Czervionke LF. Image-Guided Spine Intervention. WB Saunders, 2003.
Oblique Lumbar Spine Target for Needle Placement
P = pedicle
S = superior articular process
T=transverse process
Arrow = target
Oblique Lumbar Spine Needle Placement
Cephalad
Approach
Lateral Lumbar Spine Needle Placement
Cephalad
Approach
Superior Articular
Process
AP Lumbar Spine Needle Placement
RF Procedure
RF
Stim Sensory
50 Hz; < 1 volt
Stim Motor
2 Hz; < 10 volts
RF Lesion
80C; 1:30
Pulsed RF
42C; 2 minutes
RF Procedure: Sensory Testing
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Remove stylet
Insert electrode
Impedance (between 250-500 ohms)
Sensory testing (50 Hz, 0-1V)
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Pain similar to usual pain in part or in total
Referred proximal extremity pain
No true radicular pain
If no pain, shut off and reposition needle
RF Procedure: Motor Testing
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Motor testing (2 Hz, 1-10V)
 Ramped to at least double the sensory stimulation
value with a minimum of 3V
 Rhythmic thumping in back or neck
 Multifidus muscles
 Lateral branch of posterior primary ramus
 Proceed to RF lesioning
 Any contractions of gluteal or extremity
musculature is incorrect placement
 Needle must be repositioned, start with
sensory
RF Procedure
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Once patient has passed impedance, sensory and
motor testing, lesioning can proceed
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No further manipulations of the needle
Deep local anesthetic (1% lidocaine) through spinal needle
for thermal lesioning (not needed for pulsed)
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Take care not to move needle at all
Use a non-luer lock connecting tube to connect local syringe to
cannula
Obtain lateral spot image prior to moving stylet and compare to
spot image taken after injecting local and placing electrode into
cannula
RF Lesion Mode (Or Standard RF)
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Lesioning protocol
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80° Celsius for 60° seconds
Temperature slowly ramped up (manual or auto)
Evaluate for signs of improper needle position
Remain at maximum temperature for 60 seconds
Remove electrode, instill steroid (optional)
Remove needle
Perform other level(s)
Pulsed RF Mode
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50 Hz stimulation
Correct impedance if > 450 Ohms
Frequency 2 Hz
Pulse Duration 20 msec
45 Volts
2-4 minutes
Decrease voltage or pulse frequency if
temperature > 42°C
Complications
Bleeding
 Infection
 Thecal sac puncture and headache
 Allergic reactions to the medications
 Pneumothorax in thoracic procedures
 Vasovagal reactions and ataxia especially in cervical
procedures
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Fenton DS, Czervionke LF. In Image-Guided Spine Intervention. WB
Saunders, 2003.
Waldman SD. In Interventional Pain Management, 2nd edition. WB
Saunders, 2001.
Complications continued…
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Post-denervation neuritis
 Distributional sunburn-like feeling
 More annoying than painful
 Resolves spontaneously in 6-8 weeks
 Membrane stabilizing agents to treat
 Gabapentin (Neurontin)
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Steroids
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Deafferentation syndrome
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Permanent damage to the nerve root
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Hyperexcitability of primary sensory neurons
Fenton DS, Czervionke LF. In Image-Guided Spine Intervention. WB
Saunders, 2003.
Waldman SD. In Interventional Pain Management, 2nd edition. WB
Saunders, 2001.
Case Study
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RL follow up 6 weeks post RFA
Neurologic exam intact
Reports 60-70% overall improvement
Still has morning pain when he gets out of bed, but
significantly better
Started on home based PT exercises
Follow up based on recurrence of pain
Questions?
Thank you!