Needle-based pulsed radiofrequency (PRF – Pulsed Radiofrequency) is a safe neuromodulation technology that modulates the nerve without damaging it. Ideal in situations where classical thermolesion is too risky – for example with mixed (sensory-motor) nerves, spinal nerve roots (DRG) or the trigeminal ganglion.

How Does PRF Differ from Classical RFA?

Classical thermolesion (RFA) produces a continuous radiofrequency current at 80–90°C, which thermally destroys the nerve. PRF works entirely differently: the radiofrequency current is delivered in short pulses (typically 5–20 ms every 0.2–0.5 s, totalling 120–360 seconds), with a duty cycle that allows the tissue to dissipate heat between pulses. As a result, the temperature at the needle tip never exceeds 42°C – the threshold for thermal nerve damage.

The mechanism of PRF’s analgesic effect is complex and extends beyond a purely thermal mechanism. Current research points to a combination of:

  • Modulation of gene activity in DRG neurons and the spinal cord (including changes in c-fos and ATF-3 expression) – long-term neuroplasticity
  • The effect of a strong high-gradient electrical field (up to 200,000 V/m) on nerve cell membranes
  • Selective action on C and Aδ fibres (pain) without damaging Aβ fibres (fast sensory) and motor fibres
  • Anti-inflammatory action – reduction of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) in the nerve vicinity
  • Modulation of pain pathways in the spinal cord (central action, not only peripheral)

Indications – When to Choose PRF Instead of RFA?

  • Radicular pain (sciatica, cervicobrachial neuralgia) – PRF of the dorsal root ganglion (DRG) C5–C8, L4–S1 – RFA cannot be used here as it would destroy the entire root (including motor function, causing subsequent weakness)
  • Trigeminal neuralgia – PRF of the Gasserian ganglion, an alternative to more invasive procedures (balloon compression, glycerol neurolysis)
  • Glossopharyngeal neuralgia – PRF of cranial nerve IX
  • Facial pain – PRF of the sphenopalatine ganglion (cluster headaches, facial neuralgias)
  • Instability and pain of the atlantooccipital (C0/C1) and atlantoaxial (C1/C2) joints – an area where RFA carries too much anatomical risk
  • Shoulder pain – PRF of the suprascapular nerve
  • Hip joint pain – alternative to RFA in patients with mixed innervation
  • Pudendal neuralgia – PRF is preferred due to preservation of function
  • Polyneuropathy / CRPS – PRF of the sympathetic trunk (L2–L4 ganglia, stellate ganglion)
  • Visceral pain (abdominal pain of inflammatory or oncological origin) – PRF of the splanchnic nerves Th11/Th12
  • Patients with mixed sensory-motor nerves where RFA would cause muscle paralysis

Advantages of PRF Technology

  • Preserves structural integrity of the nerve – no risk of post-denervation neuralgia (anaesthesia dolorosa)
  • No risk of painful neuroma formation
  • Safe in the vicinity of motor nerves – does not cause paralysis
  • The effect can be repeated multiple times without cumulative damage
  • Shorter recovery period than after RFA (typically pain-free within 1–2 days of the procedure)
  • Applicable in anatomical areas unreachable by RFA

Procedure Sequence

  • Qualifying consultation – assessment of pain character, imaging studies, possible performance of a diagnostic block.
  • Patient positioning and local skin anaesthesia.
  • Under fluoroscopic X-ray (and/or ultrasound) guidance, introduction of the needle with electrode to the precisely selected location – e.g. the intervertebral foramen (DRG), the foramen ovale (Gasserian ganglion), the pterygopalatine fossa.
  • Sensory stimulation (50 Hz, 0.5 ms) – the patient confirms feeling ‘their familiar’ pain (paraesthesia in the innervation area). Motor stimulation (2 Hz, 1 ms) – checking distance from motor nerves.
  • PRF application: 5–20 ms pulses at 2–5 Hz for 120–360 seconds (typically 2 cycles), at temperature ≤42°C.
  • For radicular pain: administration of steroid and local anaesthetic periradicularly for additional anti-inflammatory effect, or without steroid (per Leiden consensus).
  • 30-minute observation period and discharge home.

Preparation

  • Current imaging studies (MRI for radicular pain, X-ray for joints)
  • Discontinuation of anticoagulants per protocol
  • No need to fast (with local anaesthesia)
  • Return transport
  • Contraindications: pregnancy, active infection, coagulopathy, cardiac pacemaker – cardiology consultation required in the latter case

Effects

  • First effects: 1–4 weeks after the procedure (effect develops gradually)
  • Full effect: 6–8 weeks
  • Duration of effect: 6–18 months, individually variable
  • For radicular pain, the proportion of patients with significant relief is 50–70% (controlled studies)
  • For trigeminal neuralgia, PRF of the Gasserian ganglion provides relief in 60–70% of patients (case series, Simopoulos et al.)
  • The procedure can be safely repeated

Possible Side Effects

  • Transient pain at the puncture site (a few days)
  • Minor subcutaneous haematoma
  • Very rarely – transient pain intensification in the first days after the procedure (biological effect, resolves spontaneously)
  • Risk of serious nerve complications is minimal due to the absence of thermal destruction

FAQ

Is PRF weaker than classical RFA?

Not necessarily – PRF and RFA have different indications. Where RFA is possible (purely sensory nerves), it usually provides a longer effect. But where RFA is risky (mixed nerves, spinal roots, ganglia, facial neuralgia), PRF is the only safe option – and is very effective in appropriately selected indications.

How many PRF sessions are needed?

In most indications, 1 session is sufficient. The procedure can be repeated after 6–12 months if pain returns. In difficult cases (e.g. refractory trigeminal neuralgia), a second session is possible after 4–6 weeks.

Is the procedure painful?

No – we administer local anaesthesia to the skin and deeper tissues. During the PRF itself, the patient feels only gentle vibration or tingling in the innervation area.