An effective intervention for chronic pain

1. ROLE OF RADIOFREQUENCY ABLATION IN
CHRONIC PAIN MANAGEMENT
PRESENTER:DR KAUSTAV BASU THAKUR
MODERATOR: DR AKOIJAM JOY SINGH

2. INTRODUCTION
Chronic pain
 Continuum of therapies available
 Failed conservative management- interventions
INTERVENTIONS
DIAGNOSTIC THERAPEUTIC

3. INTRODUCTION CONTD
• Neurolysis – destruction of nerves
• Known for centuries
• Interrupt nociceptive pathways
• Long term control of pain
• Various methods available

4. RADIOFREQUENCY ABLATION
• Minimally invasive, target selective
• Reduces pain in several chronic conditions
• Produces temperature controlled target nerve destruction
(thermocoagulation)
• Reduces pain by pain transmission modulation

5. OBJECTIVE
Deposit enough RF power into tissue to raise the temperature
of the target tissue above 45-50°C

6. HISTORY
• 1920s- Cushing did series of experiments to show utility
of RF technique
• 1930s- Kirschner used high frequency lesions of
Gasserian ganglion for trigeminal neuralgia
• 1950s- Hunsperger & Wyss proposed high frequency
alternating current for 1st time
• 1950s- Cosman & Arnoff produced first commercially
available RF generator

7. HISTORY CONTD
• 1975- First application for spinal pain by Shealy
• 1980s- Sluijter developed percutaneous RF technique for
cervical, lumbar, thoracic & sacral discogenic pain
syndromes
• 1994- Sluijter developed pulsed RF mode

8. PRINCIPLE
A high frequency current of 500 kHz produced by the RF
generator on the neural tissue through a closed circuit
produces neurolysis of the target nerve

9. PHYSICS OF THERMOCOAGULATION
Basic RF circuit
 RF generator machine
 Active electrode
 Cables
 Ground pad

10. RF Generator RF Needle & Cable
Ground Pad

11. A Closed Circuit

12. High frequency , low energy
current
Builds electromagnetic field
between electrodes
Free charged ions move back
and forth to cause oscillation &
collision
Friction raises temperature in
the tissues
Sensed by the active tip of
electrode

14. ACTIVE ELECTRODE/CANNULA
• Available in 5,10,15 cm size lengths
• Reusable/disposable
• Exposed tip delivers RF current
• Variables of RF cannula
 Total length of cannula
 Length of exposed tip
 Sharpness
 Type of tip (curved/straight)

15. LESION
• Shape- an inverted cone
• Size and consistency depends on
1) Electrode tip configuration
2) Temperature
3) Local tissue characteristics
4) Rate of thermal equilibrium
5) Time

16. ADVANTAGES
• Minimally invasive
• Lesion size accurately controlled
• Accurate placement of cannula
• Lesions can be reproduced
• Recovery rapid
• Minimum morbidity & mortality

17. INDICATIONS
• Nociceptive pain
• Neuralgic pain
• Sympathetically mediated pain
• Cancer related pain
• Mixed pain syndromes
• Neuropathic pain

18. CONTRAINDICATIONS
ABSOLUTE
• Infection
• Coagulopathy
• Pregnancy
• Deafferentiation pain
• Failed diagnostic block
• Not a replacement to
surgery
RELATIVE
• Patients with Pacemaker
• Pain relief lasting less
than 3 months

19. PATIENT SELECTION CRITERIA
• Contraindications to be ruled out
• Any chronic pain condition considered
• Favourable response to diagnostic blocks with at least
50% pain relief
• Patient must have realistic expectations

20. MINIMAL STANDARDS AND
RECOMMENDATIONS
• Multidisciplinary patient selection
• Prior diagnostic block/blocks
• Informed consent
• Fluoroscopic guidance
• Standardized report
• Standardized patient follow up
• Accurate training of physicians

21. PATIENT PREPARATION
WARD
 STOP antiplatelet drugs 3-5 days before
 Routine blood tests
 Nil per oral if sedation planned
 Scheduled dose of antihypertensive, antidiabetics
confirmed
 IV access
 Peri-procedure IV antibiotics

22. PATIENT PREPARATION
PROCEDURE ROOM
 Basic monitoring available
 Resuscitation equipment & drugs
 Test mode checking of RF machine
 Appropriate cannula
 Radiation gears
 Ground pad applied
 Thermistor connection to RF machine

23. APPLICATIONS
• Facetogenic pain
• Chronic OA knee
• Discogenic pain
• DRG rhizotomy
• Sacroiliac joint pain
• Axial pain
• Trigeminal neuralgia
• Coccydynia

24. FACET JOINT SYNDROME
• Common but underdiagnosed component of LBP
• Not amenable to surgical intervention
• Difficult conservative management
• Steroids provide short term relief
• RF neurotomy has a long term success rate of 60-70% in
well selected patients

25. NERVE SUPPLY Z JOINT

26. Controlled comparative diagnostic blocks on two occasions
at least 2 weeks apart with two different duration LA drugs
to test concordant response is recommended by ASIPP &
ISIS to improve the outcome

27. FLUOROSCOPY GUIDED LUMBAR MEDIAL
BRANCH BLOCK & RF NEUROTOMY
• Position: Prone, head turned to one side
Pillow under belly to reduce lumbar lordosis
• Monitoring: BP, ECG, oxygen saturation
• IV access & sedation: not essential
• Sterility: like any other surgical procedure

28. C Arm:
 AP view considered
 Level of facet joint confirmed with
lateral view
 Squaring done
 C arm rotated to oblique view by
10-25° until grooves between SAP
and transverse process clearly
visible

30. PROCEDURE
• Skin overlying needle entry site infiltrated with 1-2%
lidocaine solution
• 22/23 G, 3.5 inch spinal needle entered
• End on view needle
• Bony contact confirmation done with AP and Lateral view
• 0.5 ml dye injected
• 0.5-0.75ml LA injected

31. TO BE REMEMBERED
• For one facet joint two adjoining level medial branches
are targeted
• For e.g. L4-5 facet is innervated by medial branch of L3
and L4 that are positioned over L4 and L5 transverse
processes

32. PROCEDURE
• RF cannula introduced and placed in
the groove
• Stylus removed and replaced by
thermistor probe
• Bare tip in contact with the desired
tissue
• Impedance on RF machine set at
200-600 ohm

33. • Sensory stimulation done at 50 Hz
• Confirmed by paraesthesia in the area
• Motor stimulation at 2Hz
• Confirmed by twitch in the multifidus
muscle
• Once position confirmed, 1 ml of LA
with or without steroid injected to
decrease discomfort
• Lesion carried out at 80°C for 90 secs

34. POST PROCEDURE INSTRUCTIONS
• Local Ice pack application
• Systemic analgesics for 3 days
• Counselled that effect takes around 10-14 days
• Pain relief for 6 months to 2 years
• Can be repeated if pain recurs

35. Genicular Nerve Block & RF Neurotomy of
Knee Joint
• INDICATIONS
 Chronic OA knee
 Failed knee replacement
 Unfit for knee replacement
 Unfit for surgery

36. ANATOMY

38. CONCLUSION
• Useful modality when conservative methods fail
• Minimally invasive, target selective, safe & efficacious
• Enough evidence supporting use in common pain
conditions
• Requires specialised training and thorough knowledge of
neural anatomy

39. TAKE HOME MESSAGE
Appropriate use of RFTC shows promise when used
responsibly in properly selected patients & in conjunction
with a multidisciplinary approach to the treatment of pain