What to consider when choosing a Radiofrequency Generator
Radiofrequency (RF) generators sit at the centre of a modern radiofrequency pain management system, but their role extends considerably beyond the delivery of electrical energy. Contemporary systems can provide temperature control, impedance monitoring, sensory and motor stimulation, multiple lesioning modes and procedural data management, all of which can influence how effectively RF treatment is integrated into clinical practice.
Choosing a radiofrequency generator therefore requires more than comparing headline specifications. Clinicians, pain departments and procurement teams need to consider the procedures that will be performed today, the techniques that may be introduced in the future, compatibility with electrodes and cannulae, safety and testing capabilities, and how easily the equipment can be incorporated into existing clinical workflows.
These considerations have become increasingly important as radiofrequency treatment expands beyond conventional medial branch neurotomy. Contemporary interventional pain practice may incorporate conventional and pulsed RF, monopolar and bipolar lesioning, multi-probe techniques and a growing range of spinal and peripheral nerve applications.
This article considers the principal equipment factors medical professionals should assess when selecting an RF generator and examines how systems such as the Diros OWL URF-3AP with MLA-4 can meet the requirements of a diverse interventional pain service.
Disclaimer: This article is intended as a general educational resource for healthcare professionals and does not constitute purchasing, procedural or individual clinical advice. Equipment selection should reflect the intended clinical application, current evidence and guidance, manufacturer instructions, institutional requirements, compatibility with approved accessories and the professional judgement of appropriately trained clinicians.
Start with the Intended Clinical Applications
The first consideration when evaluating any RF generator should be how the system will actually be used.
A department predominantly performing conventional lumbar medial branch radiofrequency neurotomy may have different requirements from a service performing cervical procedures, sacroiliac interventions, pulsed RF or multi-electrode treatments.
Potential applications should therefore be mapped before comparing individual systems.
Questions may include:
- Which RF procedures are currently performed?
- Is conventional thermal RF sufficient?
- Is pulsed RF required?
- Are bipolar or multi-electrode techniques undertaken?
- How many electrodes may need to be independently controlled?
- Are sensory and motor stimulation routinely incorporated?
- Is the department likely to expand its RF service?
This is particularly relevant because RF technology continues to develop. Applications now extend across spinal, sacroiliac, major joint and peripheral sensory nerve targets, meaning versatility may offer advantages over equipment designed around a narrowly defined procedure (Lee et al., 2021).
Conventional and Pulsed Radiofrequency Capability
One of the first technical specifications to examine is the range of RF treatment modes available.
Conventional RF
Conventional RF delivers continuous alternating current to generate controlled heating within tissue surrounding the active electrode. It remains central to established neurotomy procedures, including treatment of appropriately selected patients with facet-mediated pain.
For conventional RF, the generator should provide accurate control over important treatment variables such as:
- Target temperature
- Treatment duration
- RF output
- Tissue impedance
These factors interact with electrode dimensions and local tissue characteristics to determine lesion geometry (Cohen et al., 2020).
Pulsed RF
Pulsed radiofrequency uses intermittent energy delivery, permitting heat dissipation between pulses and maintaining lower electrode temperatures than conventional thermal lesioning. Its intended effect is generally considered neuromodulatory rather than conventional thermal neurodestruction.
For departments undertaking pulsed RF, a generator capable of providing both modalities avoids the need for separate platforms and offers greater flexibility across different clinical applications.
A purchasing decision should therefore consider not only today’s procedural requirements but the likely direction of the service over the expected working life of the equipment.
Temperature Monitoring and Control
Temperature is one of the fundamental variables in conventional RF lesion formation.
However, the relevant consideration is not simply whether a generator can reach a specified temperature. The ability to monitor and regulate temperature accurately throughout energy delivery is important for reproducibility.
RF lesion size is influenced by temperature alongside:
- Duration
- Electrode gauge
- Active tip dimensions
- Current density
- Tissue characteristics
- Electrode orientation
Excessive temperatures can also become counterproductive. Tissue desiccation and charring increase impedance and can interfere with continued energy transfer, potentially creating less predictable lesion geometry. Contemporary safety guidance recommends monitoring both temperature and impedance at the electrode tip and cautions against conventional lesioning above 90°C (Safety Practices for Interventional Pain Procedures, 2025).
For equipment selection, clinicians should therefore assess the quality of temperature monitoring and control rather than viewing maximum temperature capability as a measure of generator performance.
Impedance Monitoring
Impedance represents the opposition encountered by electrical current passing through the treatment circuit and biological tissue.
It provides useful real-time information during RF procedures because tissue composition, electrode contact and changes occurring during heating can influence electrical resistance.
Abnormally high or low readings may alert the clinician to factors requiring investigation, while changes during lesioning can provide additional information about conditions surrounding the electrode.
Modern RF equipment should therefore provide clear impedance monitoring throughout relevant operating modes.
When multiple electrodes are used, the ability to observe impedance independently across treatment channels can become particularly useful.
Sensory and Motor Stimulation
Another important consideration is whether nerve stimulation is incorporated into the RF platform.
Sensory and motor stimulation can provide physiological information to complement anatomical positioning under fluoroscopy or other image guidance.
Sensory stimulation may help establish proximity to the intended target, while motor stimulation can assist in identifying unintended proximity to motor structures.
The role of stimulation is not identical across every procedure, and professional guidance is not completely uniform. ASPN guidance recommends sensory and motor testing before lumbar medial branch RF neurotomy, whereas other recent safety guidance states that stimulation is not required for safety or efficacy where appropriate electrode positioning is otherwise assured (Lee et al., 2021; Safety Practices for Interventional Pain Procedures, 2025).
For equipment procurement, the important point is therefore capability. A generator offering integrated sensory and motor stimulation gives clinicians the option to employ stimulation when indicated by the procedure, local protocol and their clinical judgement.
Number of Independent RF Channels
The number of channels supported by an RF system can have a considerable impact on procedural flexibility.
A single-channel generator may be entirely adequate for certain applications. However, contemporary RF techniques can involve multiple electrodes, particularly where broader lesion coverage is required.
A multi-channel system may allow:
- Multiple RF probes to be connected simultaneously
- Independent monitoring of individual electrodes
- More efficient multi-site workflows
- Bipolar or multi-electrode configurations
- Greater flexibility as procedural techniques evolve
The requirement for additional channels should be considered alongside procedure volume. More capability is not automatically beneficial if it will never be utilised, but for departments performing a broad range of RF interventions, multi-channel functionality can reduce equipment limitations.
Monopolar, Bipolar and Multi-Electrode RF
The electrical configuration used during RF treatment influences lesion formation.
Monopolar RF remains widely used and creates a circuit between the active treatment electrode and a dispersive return electrode.
Bipolar RF instead passes current between two active electrodes. Electrode spacing and orientation consequently influence the resulting lesion geometry.
More advanced multi-electrode configurations can further alter the way energy is delivered across the target area.
Research into lesion size demonstrates why these distinctions matter. Lesion dimensions and morphology are influenced by the circuit configuration as well as electrode design, treatment duration and tissue properties (Cohen et al., 2020; Radiofrequency Techniques for Chronic Pain, 2022).
A department expecting to use different lesion strategies should therefore establish which configurations a prospective generator actually supports rather than assuming all RF generators provide equivalent functionality.
Probe, Cannula and Electrode Compatibility
The generator cannot be considered separately from the consumables and accessories required to deliver treatment.
Electrode characteristics can significantly influence lesion formation. Important variables include:
- Cannula gauge
- Active tip length
- Straight or curved configuration
- Temperature sensor technology
- Intended lesion configuration
Evidence examining lumbar RF technique demonstrates that cannula diameter and active tip dimensions influence lesion size, while procedural consensus has supported specific cannula configurations for particular medial branch applications (Eldabe et al., 2020).
Before selecting a generator, departments should therefore consider the complete equipment ecosystem.
Questions include whether appropriate probes and cannulae are available for current procedures, whether reusable and/or disposable options are supported where required, what connecting cables are necessary, and whether the system provides sufficient flexibility for future techniques.
Compatibility should always be confirmed against current manufacturer documentation rather than assumed on the basis of connector appearance alone.
Equipment Testing and Safety Checks
RF equipment operates as a system comprising the generator, cables, electrodes, temperature sensors and return-path components.
A fault within any element can potentially interfere with treatment delivery.
Built-in testing functionality can therefore be valuable, allowing components to be assessed before treatment begins.
Depending upon the system, testing may evaluate:
- Electrical continuity
- Probe functionality
- Cable integrity
- Temperature sensing
- RF power delivery
This can support pre-procedural checks and help identify equipment problems before the patient reaches the lesioning stage.
User Interface and Clinical Workflow
Technical capability is only one component of equipment selection.
An RF generator is likely to be used repeatedly by clinicians and theatre personnel, making usability important for both efficiency and consistency.
Departments may wish to consider:
- Clarity of treatment information
- Ease of changing between modes
- Visibility of temperature and impedance data
- User presets
- Speed of procedural setup
- Ability to manage multiple channels
- Accessibility of treatment history
A system offering extensive functionality but requiring unnecessary complexity for routine procedures may create workflow disadvantages.
Conversely, a well-designed interface can make sophisticated capabilities accessible without disrupting established clinical practice.
Procedure Recording and Standardisation
Reproducibility is increasingly important within evidence-based interventional medicine.
Clinical research into RF techniques has specifically highlighted the importance of consistent generators, consumables and lesion parameters when attempting to standardise lesion generation (Eldabe et al., 2020).
Equipment capable of retaining procedure information or predefined user parameters may therefore help departments develop more consistent workflows.
Stored settings should never replace individual clinical decision-making, but they can provide a useful starting point for commonly performed procedures and reduce unnecessary variation in equipment configuration.
The Diros OWL URF-3AP with MLA-4
The Diros OWL URF-3AP with MLA-4 provides an example of an RF system designed around many of these considerations.
Supplied by Polar Medical to NHS and private hospitals, the system combines radiofrequency lesion generation, nerve stimulation, temperature monitoring and impedance measurement within a single platform.
Continuous and Pulsed RF
The Diros OWL supports both continuous and pulsed radiofrequency, enabling a single generator to accommodate different RF treatment approaches.
With the MLA-4 Multi-Lesion Adapter, available lesion modes include:
- Continuous monopolar RF
- Pulsed monopolar RF
- Bipolar RF
- Dual bipolar RF
- Quadrapolar™ RF
This provides flexibility for departments performing established procedures while also supporting a broader range of lesion configurations.
Four Independently Controlled RF Probes
The MLA-4 enables the generator to independently control up to four RF probes simultaneously.
For clinicians using multi-probe approaches, this can improve procedural flexibility while allowing treatment parameters to be managed across individual channels.
The system provides simultaneous impedance monitoring across up to four channels and permits automatically controlled RF output with simultaneous or staggered starts, as well as manual RF output control.
Temperature Monitoring
The URF-3AP with MLA-4 supports thermistor and/or thermocouple temperature sensing, with automatic and manual temperature control.
The manufacturer’s current specifications state a monitoring range of 20°C to 110°C.
For interventional pain procedures, this capability allows temperature information to remain visible throughout treatment and supports controlled energy delivery according to the selected protocol.
Sensory and Motor Stimulation
Sensory and motor stimulation are incorporated directly into the system.
Stimulation can be delivered using constant-voltage or constant-current modes, giving clinicians flexibility when performing physiological testing before RF treatment where appropriate.
Integrating stimulation into the same platform reduces the requirement for separate equipment and enables clinicians to move from localisation and testing into treatment within a unified workflow.
Probe and Cable Testing
The Diros OWL includes an integral RF probe and cable testing system.
This allows users to assess aspects including:
- Electrical continuity
- Power delivery
- Temperature accuracy
- Cable and probe functionality
For departments undertaking frequent RF procedures, the ability to check the treatment system before use can assist equipment management and troubleshooting.
Accessory Compatibility
The Diros system is supported by a broader range of RF probes, cannulae and connecting cables, including thermistor and thermocouple probe options and compatibility with specialist Diros cannula configurations.
For example, Diros offers disposable facet-denervation RF probe/temperature sensors for multiple cannula lengths, while appropriate adapter cables enable compatible accessories to connect to the URF-3AP and MLA-4.
This illustrates why generator procurement should consider the wider accessory ecosystem rather than evaluating the console in isolation.
Procedure History and User Presets
The system’s history recorder can retain information for the last 127 procedures and provides USB output.
Up to five users can also store customised display and procedure parameters as default settings, with optional password protection.
For multi-clinician departments, these features can support more efficient setup while allowing individual practitioners to maintain preferred configurations.
Considering the Complete RF Platform
Selecting an RF generator should ultimately involve evaluation of the complete clinical platform rather than one specification in isolation.
Temperature accuracy is important, but so are the electrodes responsible for delivering energy.
Multiple lesion modes provide flexibility, but only if they correspond with procedures supported by clinical evidence and undertaken by the department.
Stimulation capability may be valuable, but its application must remain procedure-specific.
Likewise, a multi-channel system offers advantages only when the clinical workflow benefits from simultaneous or independently controlled probes.
The most appropriate RF generator is therefore one that aligns its technical capabilities with the clinical requirements of the service.
Planning for Future Requirements
RF pain management continues to evolve.
Peripheral nerve applications, alternative lesion configurations and the continued investigation of pulsed RF mean that equipment purchased today may be expected to accommodate different procedures during its service life.
Departments may consequently benefit from considering:
- Current procedure volumes
- Planned expansion of pain services
- Clinician training requirements
- Accessory availability
- Equipment servicing and support
- Future consumable requirements
- Compatibility with evolving RF techniques
This longer-term perspective can be particularly valuable when RF equipment represents a significant capital investment.
Conclusion
Choosing a radiofrequency generator requires considerably more consideration than comparing maximum power or temperature specifications.
For medical professionals and procurement teams, important factors include conventional and pulsed RF capability, temperature regulation, impedance monitoring, sensory and motor stimulation, supported lesion configurations, channel capacity, electrode compatibility, equipment testing and the usability of the overall system.
These features directly influence how readily an RF generator can accommodate the range of procedures performed within contemporary interventional pain medicine.
The Diros OWL URF-3AP with MLA-4 brings many of these capabilities together within one platform, supporting continuous and pulsed RF, monopolar and multi-electrode configurations, up to four independently controlled probes, sensory and motor stimulation, multi-channel impedance monitoring and comprehensive probe and cable testing.
Ultimately, however, equipment selection should begin with clinical requirements. By assessing the complete RF system against current procedural needs and likely future developments, hospitals and pain services can select technology capable of supporting safe, controlled and efficient RF treatment over the longer term.
References
(Cohen SP et al., 2020)
(Lee DW et al., 2021)
(Eldabe S et al., 2020)
(Radiofrequency Techniques for Chronic Pain, 2022)
(Safety Practices for Interventional Pain Procedures, 2025)
(Diros Technology, OWL URF-3AP Product Specifications)
(Diros Technology, OWL URF-3AP + MLA-4 Product Specifications)
(Diros Technology, OWL Universal RF System URF-3AP Operator’s Manual, Rev. 7.0)