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What is “Cool” about
Radiofrequency
Ramsin Benyamin, MD
Disclaimer
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Founder/President/Medical Director, Millennium Pain Center, Illinois:
Bloomington-Normal, Decatur, Peoria, Des Plaines, Libertyville, Evanston, Chicago
Co-founder, Millennium Pain Management-Teknon Medical Center, Barcelona, Spain
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Clinical Assistant Professor of Surgery, College of Medicine, University of Illinois
Adjunct Professor, Department of Biological Sciences, Illinois State University
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Past-President, American Society of Interventional Pain Physicians (ASIPP)
President-Elect, American Society of Interventional Pain Physicians (ASIPP)
Board of Directors, SIPMS
Past-President, Illinois Society of Interventional Pain Physicians
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Board of Examiners, American Board of Interventional Pain Physicians (ABIPP)
Member, Guidelines committee, ASIPP
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Associate Editor, “ Pain Physician”
Editorial Board, “ Pain Practice”
Editorial Board, “Journal of Opioid Management”
Reviewer, “Neurosurgery”, “Neuromodulation”, “ Journal of Neuro-Interventional Surgery”
Disclaimer
• Clinical research/Teaching/lecture:
Kimberly Clark
Principle of Ionic Heating
 RF energy is applied
 Ions in surrounding tissue move creating friction1
 Friction heats
surrounding tissue
 Hot tissue heats probe or electrode by conduction
 Probe thermocouple located at the tip, reads
tissue temperature
1. Organ LW. Appl Neurophysiol 1976;39:69-76.
Independent Lesion Parameters
• Electrode Shape: Lesion size is influenced by the length and gauge of the electrode2,3
• Lesion size increases with surface area Longer: longer
Wider: wider
20 Ga. 10mm
18 Ga. 10mm
2.
Bogduk N, Macintosh J, Marsland A. Neurosurgery 1987;20:529-35.
3.
Alberts WW, Wright EW, Jr., Feinstein B, et al. J Neurosurg 1966;25:421-3.
20 Ga. 4 mm
Internally Cooled Electrodes
5. Goldberg SN, Gazelle GS, Solbiati L, et al. Acad
Radiol 1996;3:636-44.
6. Lorentzen T. Acad Radiol 1996;3:556-63.
7. Wittkamp FHM, Hauer RN, Robles de Medina EO. J
Am Coll Cardiol 1988;11.
Physics of Cooled RF
Conventional RF
Cooled RF
Testing performed in chicken (37°C) for 3:00 at a set temperature of 70
°C. Electrode: 18 Gauge, 4mm active tip.
Physics of Cooled RF
• “3D” sphere
• Increasing radius ‘r’by a factor of 2 increases volume ‘V’ by a factor of 8 according to V = 4/3πr3
Cooled vs. Non-Cooled RF Lesions
Standard RF:
Internally Cooled RF Probe
V = ‘x’
mm3
4 mm
V = 8‘x’
mm3
Internal cooling doubles the lesion radius and
increases the lesion volume by a factor of 8
8 mm
Thermal vs. Cooled RF
Temperature 80° C
Non-cooled
Cooled
45° C
r
Distance
Probe
Conventional RF lesion size is limited by heat generated in
the tissue adjacent to the electrode
Cooling tissue adjacent to the electrode (via cooling the RF
probe) increases radius of overall effective heating.
Cooled RF Lesion Properties
Cooled RF‐ 18Ga, 4mm
Size and shape of cooled RF lesions are a function of: Electrode length/ geometry
Set temperature
Time (Duration)
Coolant Flow Rate
Coolant Temperature
40%
10 mm
Testing performed in chicken (37°C)
for 3:00 at a set temperature of 70 °C.
Large Spherical, Forward Projecting Lesion
Cooled RF
Conventional RF
Application to Discogenic Pain
Cooled RF for Sacroiliac Joint Pain
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Large Cooled-RF lesions are positioned in a lateral arc around each
dorsal sacral aperture
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Nine targets create a combined lesion volume adequate to
compensate for known anatomical variations
SInergy Cooled RF Lesioning pattern: 3 lesions created lateral
to S1 & S2 foramina, 2 lesions lateral to the S3 foramen, and 1
lesion lateral to L5 dorsal ramus.
SI Joint Pain – Patel RCT, Pain Medicine 2012
• Prospective Randomized, Double Blind, Placebo
Controlled Clinical Trial (N = 51)
• Randomized 2:1
• Criteria for cooled RF treatment
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Chronic low back pain ≥ 6 months
NRS between 4 & 8 on 10 cm scale
Failed conservative therapy
Signs/symptoms of SI-joint mediated pain
≥ 75% pain relief from dual SI lateral branch blocks
• Follow up 9 months post treatment
Patel, et al, Pain Med. 2012 Mar;13(3):38398.
SI Joint Pain – Patel RCT (cont.)
* p < 0.05
Patel, et
al
SI Joint Pain - Stelzer, Pain Med 2013
• Large, single-center, retrospective review
(N = 126)
• Criteria for cooled RF treatment
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Chronic low back pain ≥ 6 mo. & VAS ≥ 5
Signs/symptoms of SI-joint mediated pain
Failed conservative therapy
≥ 50% pain relief from single SI joint injection
• Follow up range 4-20 months
Stelzer, et al. Pain Med. 2013 Jan;14(1):29-35.
SInergy Cooled
RF Lesioning
pattern: 3 lesions
created lateral to
S1 & S2
foramina, 2
lesions lateral to
the S3 foramen,
and 1 lesion
lateral to L5
SI Joint Pain (Stelzer cont.)
KEY RESULTS
4-6
Months
6-12
Months
> 12
months
50% Reduction in Pain
86%
71%
48%
VAS 2 Point Reduction in Pain
92%
84%
74%
QOL “Improved” or “Much Improved”
96%
93%
85%
Stopped or Decreased Use of Opioids
100%
62%
67%
Author Conclusions:
• Results support use of cooled RF for patients who fail
conservative treatment
• Decreases in pain & medication usage may justify use
in a broader population
Stelzer, et al. Pain Med. 2013 Jan;14(1):29-35.
SI Joint Pain – Cohen RCT, Anesth. 2008
• Prospective Randomized, Double Blind, Placebo Controlled
Clinical Trial (N = 28)
• Criteria for cooled RF treatment
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Chronic low back pain ≥ 6 mths
Failed conservative therapy, including corticosteroid injections
Signs/symptoms of SI-joint mediated pain
≥ 75% pain relief from single diagnostic SI joint injection
• Randomized 1:1
• Follow up 6 months
• % success defined as:
– ≥ 50% reduction in NRS pain
AND
– A positive Global Perceived Effect (GPE)
AND
– A 10 point decrease in ODI (Oswestry Disability Index)
OR
– A 4 point decrease in ODI coupled with reduction in medication usage.
Cohen, et al, Anesthesiology. 2008 August; 109(2): 279–288.
SI Joint Pain – Cohen RCT (cont.)
“The proportion of subjects who
experienced a “positive
outcome” was significantly
higher in the denervation group
than in the control group (p <
0.001). This success rate
persisted at 3- and 6- month
follow up visits”
Author Conclusions:
“Results support use
of cooled RF for
patients to treat
presumptive
Sacroiliac joint pain”
Cohen, et al.
SI Joint Pain Predictor – Cohen,
Reg Anesth and Pain Med 2009
• Retrospective study (N = 77)
• Focus of study was to identify factors
associated with SI joint RF denervation
outcomes.
• Reviewed Conventional RF and Cooled RF
• Outcome Measures:
– Success = VAS Pain Score decrease > 50% for
6 months and positive Global Perceived
Effect.
– Follow up 6 months post procedure
Cohen, et al, Reg Anesth and Pain Med . May/June 2009;Vol 34, number 3:206-214
SI Joint Pain Predictor – Cohen (cont.)
Author Conclusions:
“The use of Cooled, rather than Conventional RF, was associated
with a higher percentage of positive outcomes.”
“The only positive predictor of a successful outcome was the
use of Cooled RF technology.”
Cohen, et al.
Conventional RF
Current technology for lumbar
neurotomy uses conventional
RF. Lesions created are:
Oval shape
• Requires parallel trajectory
Volume
• Requires precise
placement
• May require multiple
passes
Cooled RF Lesions
Cooled RF technology offers
lesions with different set of
characteristics:
Spherical shape
Distally projecting
Large volume
Approach angle independent
40
%
14 mm
Cooled RF, 18Ga, 4mm
Cooled RF for treatment of thoracic z -joint
UPPER
UPPER
12
mm
MID
MID
12 mm
LOWER
LOWER
12
mm
Variable
path
Optimized
lesion size
Consistent ablation
of thoracic z -joint
MB
Complex Anatomical
Structures
A sub group of patients may be more
difficult to treat due to:
Disordered anatomy:
• Degenerative changes with age
• Enlarged z-joint
• Scoliosis
• Obesity
Modified anatomy:
• Presence of surgical implants
• Scar tissue formation in vicinity of
joint
Cooled RF – Coagulation zone
Visual Image
Infrared Image
Red = Temp between 45 and 55 oC
Yellow = Temp above 55 oC
New Applications
Are We Doing Too Many TKRs?
Peter McCann, MD; Editorial 2012
• JAMA: Increase in 20 years: 161% in primary, 106% in revision
TKR: aging, obesity
• Actual per capita increase: tripled in 20 years
• 5 Billion dollars a year
• CMS: MR: surgery is reasonable/necessary
• Overuse not substantiated
• Welcomes transparency, independent analysis, peer review
Efficacy of pulsed radiofrequency treatment on the
saphenous nerve in patients with chronic knee pain
Mert Akbasa,∗, Nurettin Lulecib, Kamer Derea, Emel Lulecic, Ugur Ozdemird and Huseyin Toman
Journal of Back and Musculoskeletal Rehabilitation 2011
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N: 115 patients
PRF of infrapatellar branch of Saphenous nerve x8minutes
Follow-up: 6 months
WOMAC,VAS in rest, movement, flexion
Patient response to different treatment
Patient requiring second dose of PRF treatment after 3 months
Patient requiring second dose of PRF treatment after 6 months
Patient reporting > 50% decrease in VAS after 6 months
Patient reporting satisfaction by WOMAC Score after 6 months
(excellent or good)
Number of patients (%)
0 (0%)
3 (2.6%)
115 (100%)
113 (98.2%)
Radiofrequency treatment relieves chronic knee osteoarthritis pain:
A double-blind randomized controlled trial
Woo-Jong Choi a, Seung-Jun Hwang b, Jun-Gol Song a, Jeong-Gil Leem a, Yong-Up Kang c, Pyong-Hwan Park
a, Jin-Woo Shin
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38 patients randomized
Kellgren-Lawrence grade: 2-4
Single diagnostic block: 2ml Lidocaine 2%
SL, SM, IM geniculate nerves: 70c x 90s
Periosteum @ junction of shaft & epicondyle
Follow-up: 1, 4, 12 weeks
VAS, GPE, Oxford knee score
59% had >50% relief
Anteromedial view of the right knee joint. (A)
The superior medial genicular nerve (1) runs
down the upper part of the medial epicondyle
(asterisk) of the femur with genicular vessels
(2). The adductor magnus (3) which is inserted
into the adductor tubercle on the medial
condyle of the femur. (B) The inferior medial
genicular nerve (1) passes the lower parts of
the medial epicondyle (asterisk) of the tibia.
The tibial collateral ligament (2) which is
attached to the medial condyle of the tibia
Percutaneous Radiofrequency Treatment for Refractory
Anteromedial Pain of Osteoarthritic Knees
Masahiko Ikeuchi, MD, PhD,* Takahiro Ushida, MD, PhD,*† Masashi Izumi, MD,* and Toshikazu Tani, MD, PhD
Pain Medicine, 2011
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RF(18) vs. nerve block(17)
Kellgren-Lawrence: grade 3-4
3 weeks washout/abstinence
Medial retinacular nerve, infrapatellar branch of saphenous
RF: 70 x 90s repeat in 2weeks
Follow-up: 6 months
Articular innervation
• Anteromedial joint: obturator nerve
• Anterolateral joint: femoral nerve
• Posterosuperior joint: sciatic nerve
• Posteroinferior joint: nerves to quadratus femoris muscle
• Posterolateral joint: superior gluteal nerve
The sensory innervation of the hip joint - An anatomical study
Surgical Radiologlc Anatomy
Journal of Clinical Anatomy
K. Birnbaum l, A. Prescher2, S. Hef31er1 and K.-D. Heller 1
© Springer-Verlag 1997
Percutaneous Radiofrequency Lesioning of Sensory Branches of the Obturator
and Femoral Nerves for the Treatment of Hip Joint Pain
Masahiko Kawaguchi, M.D., Keiji Hashizume, M.D., Toshio Iwata, M.D., and Hitoshi Furuya, M.D.
Regional Anesthesia and Pain Medicine, 2001
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N: 14 patients
Single diagnostic block: nerve/joint
RF: obturator in 9, obturator and femoral in 5
VAS: 6.8 to 2.7
86% had %50 for 1-11 months
Fig 3. Fluoroscopic image showing the Sluijter-M ehta
cannulae for the radiofrequency lesioning of sensory
branches of left obturator nerve. The tip of the cannula
was located near the anteromedial aspect of the extraarticular portion of the hip joint, the site below the inferior
junction of the pubis and the ischium, which appears
teardrop in shape in the antero-posterior radiograph. After the injection of 2 mL mepivacaine, radiofrequency
thermocoagulation was performed at 80°C for 90 seconds.
Percutaneous Radiofrequency Lesioning of Sensory Branches of the Obturator
and Femoral Nerves for the Treatment of Non-Operable Hip Pain
Atif Malik, MD, Thomas Simopolous, MD, Mohamed Elkersh, MD, Musa Aner, MD, and Zahid H. Bajwa, MD
Pain Physician, 2003
• Case series: 4 patients
• Single diagnostic nerve block: 1ml Marcaine
0.25%
• All 4 had reduction in VAS
• 3 had improved function
• 2 had reduction in pain meds
Pulsed Radiofrequency Treatment of Articular Branches of the Obturator
and Femoral Nerves for Management of Hip Joint Pain
Hong Wu, MD, MS; John Groner, MD ; Pain Practice 2007
• Case report: 2 patients
• Single diagnostic block: 0.5-1ml Lidocaine 1%
• 50% pain relief & improved function: 3-4 months
Percutaneous Radiofrequency Denervation in Patients With
Contraindications for Total Hip Arthroplasty
FABRIZIO RIVERA, MD; CARLO MARICONDA, MD; GIOVANNI ANNARATONE, MD
ORTHOPEDICS , March 2012
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N: 16
Single diagnostic block: Ropivacaine: 3ml
Follow-up: 6 months
Mean VAS: 9.52 to 6.35
Harris Hip Score: 28.64 to 43.88
Mean WOMAC (OA index): 75.70 to 63.70
8 patients: >50% relief at 6 months
No side effects: 3 cases of hematoma
In conclusion…
“Learn from the mistakes of others.
You can’t live long enough to make
them all yourself.”
Eleanor Roosevelt
I have my faults, but being wrong ain't one of them.
Jimmy Hoffa
Thanks!
[email protected]