Radiofrequency Ablation 101

Transcription

1 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

2 What s in a name? Radiofrequency Ablation RFA Rhizotomy Neurotomy

3 Rhizotomy Interventional pain modality designed to decrease the sensation of pain by denervating the source Provides partial relief Provides temporary relief/can be repeated

4 Common Applications Lumbar facet pain Cervical facet pain Thoracic facet pain Sacroiliac joint pain

5 Less Common Applications Regional neuropathic pain syndromes Sympathectomy Ganglion lesion Nociceptive pain syndromes Knee Hip Heel

6 Facet Syndrome Diagnosis 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

7 Case Study 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 L4-5, facet arthopathy L3-S1 with subchondral cyst L5-S1, no central stenosis

8 Conservative Treatment 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

9 RF and Treatment Modality Facet related pain must be meticulously established At least 2 diagnostic procedures 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

10 Case Study 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

11 Lets Cook 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

12 Facet Denervation Destruction of the nerve supply to the facets Medial branches C3-L4 Third occipital nerve Posterior primary ramus of L5 Dual nerve supply Proper nomenclature C8 spinal nerve changes everything

13 Landmarks MB = medial branch NR = nerve root TP = transverse process TON = 3rd occipital nerve VA = vertebral artery IC = iliac crest LB = lateral branch DPR = dorsal primary ramus SAB = superior articular branch IAB = inferior articular branch

14 RF and Patient Selection 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

15 Equipment Radiofrequency generator (Thermal and/or Pulsed) Grounding pad and connecting cable Electrodes and disposable needles 5cm, 10cm, 15cm needles (5 or 10mm active tips) 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

16 Preparation for Procedure Fluoroscopically assess anatomy Anatomy and nerve nomenclature 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

17 Lumbar PA and Lumbar Oblique MB = medial branch NR = nerve root TP = transverse process FJ = facet joint IC = iliac crest LB = lateral branch DPR = dorsal primary ramus SAB = superior articular branch IAB = inferior articular branch IBP = intermediate branch plexus S = superior articular process I = inferior articular process Images from Fenton, DS, Czervionke LF. Image-Guided Spine Intervention. WB Saunders, 2003.

18 Oblique Lumbar Spine Target for Needle Placement Images from Fenton, DS, Czervionke LF. Image-Guided Spine Intervention. WB Saunders, 2003.

19 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.

20 Oblique Lumbar Spine Target for Needle Placement P = pedicle S = superior articular process T=transverse process Arrow = target

21 Oblique Lumbar Spine Needle Placement Cephalad Approach

22 Lateral Lumbar Spine Needle Placement Cephalad Approach Superior Articular Process

23 AP Lumbar Spine Needle Placement

24 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

25 RF Procedure: Sensory Testing Remove stylet Insert electrode Impedance (between ohms) Sensory testing (50 Hz, 0-1V) 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

26 RF Procedure: Motor Testing 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

27 RF Procedure Once patient has passed impedance, sensory and motor testing, lesioning can proceed No further manipulations of the needle Deep local anesthetic (1% lidocaine) through spinal needle for thermal lesioning (not needed for pulsed) 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

28 RF Lesion Mode (Or Standard RF) Lesioning protocol 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)

29 Pulsed RF Mode 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

30 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 Fenton DS, Czervionke LF. In Image-Guided Spine Intervention. WB Saunders, Waldman SD. In Interventional Pain Management, 2 nd edition. WB Saunders, 2001.

31 Complications continued Post-denervation neuritis Distributional sunburn-like feeling More annoying than painful Resolves spontaneously in 6-8 weeks Membrane stabilizing agents to treat Gabapentin (Neurontin) Steroids Deafferentation syndrome Hyperexcitability of primary sensory neurons Permanent damage to the nerve root Fenton DS, Czervionke LF. In Image-Guided Spine Intervention. WB Saunders, Waldman SD. In Interventional Pain Management, 2 nd edition. WB Saunders, 2001.

32 Case Study 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

33 Questions?

34 Thank you!