Pulsed radiofrequency neurotomy (PRFN) is a technique where nerves are minimally heated to 42 degrees centigrade in order to relieve pain.
Most studies on radiofrequency (RF) treatment utilise constant current RF (300-500 kHz) electric current energy to heat tissue adjacent to the active needle tip. In contrast, PRFN treatment uses brief pulses of RF (~300 kHz) electrical current to induce similar voltage fluctuations at the treatment site without the thermal heights that cause tissue coagulation.15 As the “lesions” are low temperature they do not cause side-effects, such as post-RF neuropathic pain, which can occur with higher temperature treatments.
However, as PRFN does not cause neural damage, any effect must be due to some other mechanism. RFN does not induce nerve damage (axonal damage) until temperature reaches 70 degrees centigrade.12 However, findings from animal studies suggest that PRFN of the dorsal root ganglion (DRG) causes reversal of nerve injury (spinal nerve ligation)-induced tactile allodynia in rats fro at least 32 days and indicates that PRFN can speed recovery in nerve injury-induced pain.7
PRFN has been compared to RF treatment in the management of facet joint pain and been found to be substantially inferior.10 PRFN has also been pilot tested in the management of the type of discogenic pain known as internal disc disruption (IDD), with some positive long term outcomes which might be treatment related.9 However, PRFN has never been tested with a randomized controlled study.15
PRFN tends to be used to manage nerve root or more particularly dorsal root ganglion pain. It is theorised that high-voltage, long-duration intradiscal pulsed radiofrequency with the electrode in the center of the NP might work not from thermal effects but by exposure to electric fields.9
Chronic lumbosacral radicular pain (or true sciatica) has been treated with single or repeated PRFN and the procedure has been found to be at least safe.6;13 Treatment is directed at or near the DRG. The DRG is a particular component of the sensory part of the nerve root. It lies variably in the region of the foramen (just outside the foramen – this is uncommon, in the foramen or more intra-spinal). Epidural contrast can be used to outline the DRG and allow for optimisation of the needle position about 1-2 cm peripheral to the DRG. 5
Chronic headache has also been treated with PRFN directed at the C2 ganglion and the occipital nerves.14;16
Coccygeal pain has been treated with PRFN directed at the ganglion Impar, which is a plexus of nerves that lies just anterior to the coccyx within the pelvis, and also directed into the caudal space.2
Other applications include treatment of knee pain,1;3 shoulder pain,4 ankle pain,11 and neuroma.8
1. Akbas M, Luleci N, Dere K et al. Efficacy of pulsed radiofrequency treatment on the saphenous nerve in patients with chronic knee pain. J Back.Musculoskelet.Rehabil 2011;24:77-82.
2. Atim A, Ergin A, Bilgic S et al. Pulsed radiofrequency in the treatment of coccygodynia. Agri. 2011;23:1-6.
3. Karaman H, Tufek A, Kavak GO et al. Intra-articularly applied pulsed radiofrequency can reduce chronic knee pain in patients with osteoarthritis. J Chin Med Assoc. 2011;74:336-40.
4. Luleci N, Ozdemir U, Dere K et al. Evaluation of patients' response to pulsed radiofrequency treatment applied to the suprascapular nerve in patients with chronic shoulder pain. J Back.Musculoskelet.Rehabil 2011;24:189-94.
5. Moon HS, Kim YD, Song BH et al. Position of dorsal root ganglia in the lumbosacral region in patients with radiculopathy. Korean J Anesthesiol. 2010;59:398-402.
6. Nagda JV, Davis CW, Bajwa ZH et al. Retrospective review of the efficacy and safety of repeated pulsed and continuous radiofrequency lesioning of the dorsal root ganglion/segmental nerve for lumbar radicular pain. Pain Physician 2011;14:371-6.
7. Perret DM, Kim DS, Li KW et al. Application of pulsed radiofrequency currents to rat dorsal root ganglia modulates nerve injury-induced tactile allodynia. Anesth Analg. 2011;113:610-6.
8. Restrepo-Garces CE, Marinov A, McHardy P et al. Pulsed radiofrequency under ultrasound guidance for persistent stump-neuroma pain. Pain Pract 2011;11:98-102.
9. Teixeira A, Sluijter ME. Intradiscal high-voltage, long-duration pulsed radiofrequency for discogenic pain: a preliminary report. Pain Med 2006;7:424-8.
10. Tekin I, Mirzai H, Ok G et al. A comparison of conventional and pulsed radiofrequency denervation in the treatment of chronic facet joint pain. Clin.J.Pain 2007;23:524-9.
11. Todorov L. Pulsed radiofrequency of the sural nerve for the treatment of chronic ankle pain. Pain Physician 2011;14:301-4.
12. Tun K, Cemil B, Gurcay AG et al. Ultrastructural evaluation of Pulsed Radiofrequency and Conventional Radiofrequency lesions in rat sciatic nerve. Surg Neurol 2009;72:496-500.
13. van Boxem K., van Bilsen J., de Meij N. et al. Pulsed Radiofrequency Treatment Adjacent to the Lumbar Dorsal Root Ganglion for the Management of Lumbosacral Radicular Syndrome: A Clinical Audit. Pain Med 2011;12:1322-30.
14. Vanelderen P, Rouwette T, De VP et al. Pulsed radiofrequency for the treatment of occipital neuralgia: a prospective study with 6 months of follow-up. Reg Anesth Pain Med 2010;35:148-51.
15. Vivian D. Intradiscal and Peridiscal Therapies for Discogenic and Radicular Pain. In: Lennard TA, Walkowski S, Singla AK et al., eds. Pain Procedures in Clinical Practice. 3rd ed.Elsevier, 2011:461-82.
16. Zhang J, Shi DS, Wang R. Pulsed radiofrequency of the second cervical ganglion (C2) for the treatment of cervicogenic headache. J Headache Pain 2011;12:569-71.
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