Pulsed Radiofrequency: How Technique Shape Energy Delivery

Pulsed radiofrequency (PRF) continues to prompt discussion in interventional pain medicine. A central question is why clinical outcomes can vary—and how electrode positioning, energy delivery, and patient selection may contribute to those differences.

In the accompanying educational presentation, the speaker examines these questions through three connected elements: the generator that produces RF energy, the circuit that delivers it, and the biological response of the targeted tissue. This framework also provides a useful perspective on the capabilities of the Racz Neurostat™ RF Generator.

Understanding Pulsed RF

Two pulsed radiofrequency (PRF) protocols can share the same electrode-tip temperature limit and still deliver energy differently. Electrode position, circuit configuration, voltage, and application timing each describe a different part of the protocol. These details help clarify what researchers compared and how to interpret the outcomes they reported. [1–3]

How does pulsed radiofrequency differ from thermal RF?

Pulsed radiofrequency delivers RF energy in brief bursts separated by intervals that allow heat to dissipate. PRF has been studied for its potential effects on pain signaling, and its mechanisms remain incompletely understood. Continuous thermal radiofrequency uses sustained heating to create a tissue lesion. [1, 2]

Some PRF studies use an electrode-tip temperature limit of 42°C. That value refers to the temperature measured at the electrode tip. Voltage and pulse timing describe other aspects of energy delivery, while the temperature reading captures conditions at a single location. [1–3]

What changes between monopolar and bipolar RF?

Monopolar and bipolar RF differ in how they complete the electrical circuit. [4]

Monopolar RF. Current flows between the active electrode and a dispersive return electrode. When reading a study, look for where the active tip was positioned relative to the neural target. [4]

Bipolar RF. Current flows between two active electrodes. The setup is described by where each tip sits relative to the target and by the distance between the two tips. [4]

Modeling and ex vivo studies describe how electric and thermal fields vary around RF electrodes. To assess whether a configuration improves patient outcomes, look for clinical evidence specific to the neural target and RF protocol. [2]

What have studies found about PRF voltage and application duration?

What have studies found about PRF voltage and application duration?

Two randomized trials examined pulsed radiofrequency (PRF) at the dorsal root ganglion in patients with chronic lumbosacral radicular pain. One compared voltage settings. The other compared application schedules that differed in total duration. [3, 5]

Voltage — 60 V versus 45 V. Pain scores were lower in the 60 V group at six months. At one month, the difference between groups was not statistically significant. The follow-up interval matters when describing the result. [5]

Application duration — six versus twelve minutes. The study found no statistically significant difference in leg pain at three months, its primary outcome. The six-minute group received three two-minute applications separated by pauses. The twelve-minute group received a single uninterrupted application of pulsed RF. Both groups used the same electrode-tip temperature limit. The comparison therefore reflects both total application time and how that time was divided. [3]

What should clinicians look for when comparing PRF studies?

• Who was treated? The voltage and duration trials enrolled patients with chronic lumbosacral radicular pain. Start with the diagnosis and eligibility criteria when comparing either trial with a study of a different pain population. [3, 5]
• What was targeted? Both trials targeted the dorsal root ganglion. A study using similar generator settings at a different neural target addresses a different clinical question. [3, 5]
• What changed between groups? Read the full application schedule. A comparison labeled by duration can also differ in how that time is distributed, as it did in the six- and twelve-minute trial. [3]
• What was measured, and when? Keep the outcome and follow-up interval attached to the result. The duration trial’s primary endpoint was leg pain at three months. In the voltage trial, the between-group difference varied between the one- and six-month assessments. [3, 5]

Sources

1. Shanthanna H, et al. Randomized, placebo-controlled pilot study of lumbar dorsal root ganglion PRF for chronic lumbar radicular pain. Journal of Pain Research. 2014. Read the study.
2. Cosman ER Jr, Cosman ER Sr. Electric and thermal field effects in tissue around radiofrequency electrodes. Pain Medicine. 2005. Read the study.
3. Kim CS, et al. Randomized double-blind study of PRF duration in chronic lumbosacral radicular pain. Neuromodulation. 2025. Read the study.
4. U.S. Food and Drug Administration. 510(k) summary K232632. Technical description of monopolar and bipolar RF circuits.
5. Erken B, Edipoglu IS. Randomized trial of high-voltage dorsal root ganglion PRF for chronic lumbosacral radicular pain. Neuromodulation. 2024. Read the study.
6. Tang D. Pulsed Radiofrequency and Bipolar Pulsed RF [educational lecture]. PainCast. Available at: https://paincast.com/pulsed-radiofrequency-and-bipolar-pulsed-rf/ Accessed November 2026.