G4™ RF Generator Radiofrequency Ablation Prescriptive Information

Indications for Use

The Boston Scientific G4 Radiofrequency Generator is indicated for use in procedures to create radiofrequency lesions for the treatment of pain, or for lesioning nerve tissue for functional neurosurgical procedures. The Boston Scientific G4 Radiofrequency Generator is used with separately approved Boston Scientific Radiofrequency Probes.


General Information

Safe and effective Radiofrequency (RF) lesioning is dependent not only on equipment design, but also on factors under control of the operator. Do not attempt to operate the RFG-4 (G4) prior to completely reading and understanding the instructions for use applicable to each component of the Boston Scientific System, consisting of generator, generator accessories, electrodes and cannula. For generator and generator accessories, refer to this manual; for the use of electrodes and cannula, refer to the respective electrode instructions for use.

WARNING: Electric Shock Hazard

There are no user serviceable parts inside the G4. To avoid electric shock, return the device to Boston Scientific for servicing.

WARNING: Hazardous Electrical Equipment & Active Implants

This equipment is intended for use by qualified personnel only.

This equipment may damage or interfere with the operation of cardiac pacemakers and other active implants.

Do not use within 15 feet (4 meters) of a cardiac pacemaker unless proper cautions have been taken. Before use of the G4 RF Generator, contact the pacemaker company to determine whether the pacemaker needs to be converted to fixed rate pacing during the radiofrequency procedure. When the pacemaker is in the sensing mode, it may interpret the RF signal as a heartbeat and may fail to pace the heart.

This equipment has an output which is capable of causing a physiological effect.

WARNING: Risk of Burns and Fire

Do not use near conductive materials such as metal bed parts or inner spring mattresses.

WARNING: Protective Earth Grounding

Grounding reliability can only be achieved when the equipment is plugged into a receptacle marked “Hospital Grade”. Any interruption of the Protective Earth conductor will result in a potential shock hazard which cause injury to patient or operator.

WARNING: Electrical Safety Information

A needle electrode should not be used as the dispersive electrode, as it is possible to burn the patient at this site due to high current densities. In all applications, care should be taken to maximize the surface area of the dispersive electrode. The dispersive electrode should be reliably attached with its entire area against the patient’s body and as close to the operating field as possible.

General Warnings and Precautions

This section contains warnings and precautions relevant to the G4 RF Generator. Additional warnings and precautions are listed throughout this Operator's Manual.

NOTICE: The physician and support staff must be the ultimate judge of the appropriateness of, and the method used to perform any medical procedure performed using Boston Scientific equipment. It is not the province of Boston Scientific to instruct in the proper medical use of the equipment. The availability of output modes, settings values, and default settings values on the G4 RF Generator should not be construed as a recommendation of the medical appropriateness of their use in a specific case.

WARNING: Proper electrode placement should be verified using anatomical landmarks, sensory and motor stimulation techniques, fluoroscopic guidance, Impedance reading, and good clinical judgment before RF lesion making procedures are initiated.

WARNING: The long-term risks of creation of RF lesions have not been established.

Non-Boston Scientific Equipment

WARNING: Electromagnetic interference (EMI) produced by the unit during normal operation may adversely affect the performance of other equipment. The performance of this device may be adversely affected by other high frequency surgical devices in close proximity. If a problem occurs, separate the devices. Portable RF communications equipment (including peripherals such as antenna cables and external antennas) should be used no closer than 30 cm (12 inches) to any part of the generator, including cables. Otherwise, degradation of performance of this equipment could result.

WARNING: Electrodes and probes of monitoring, stimulating and imaging devices, and metallic and conductive implanted hardware or probes, can provide paths for high frequency currents even if they are battery powered, insulated, or isolated at 60 Hz. The risk of burns can be reduced, but not eliminated, by placing the electrodes or probes as far away as possible from the lesion site and from the dispersive electrode. Protective impedances incorporated into the monitoring leads may further reduce the risk of these burns and permit continuous monitoring during energy delivery. Needles should not be used as monitoring electrodes during such procedures. If any physiological monitoring or other electrical apparatus is to be used on the patient simultaneously with this G4 RF Generator, the safety aspects of the arrangement should be studied and cleared by a biomedical or clinical engineer.

CAUTION: Do not use the G4 Radiofrequency Generator with components, electrodes, and/or RF Cannulae/needles that are not approved by Boston Scientific.

The use of non-Boston Scientific approved components could negatively affect the EMC performance of the system or result in EMC non-compliance.

WARNING: Potentially hazardous conditions may exist when accessories of similar connector types are combined. Use only appropriate accessories certified by an accredited test body.

WARNING: Use of this equipment adjacent to or stacked with other equipment should be avoided because it could result in improper operation. If such use is necessary, this equipment and the other equipment should be observed to verify that they are operating normally.

WARNING: Do not touch the USB port and the patient simultaneously.

NOTE: The EMISSIONS characteristics of this equipment make it suitable for use in industrial areas and hospitals (CISPR 11 class A).

The Dispersive Electrode ("Ground Pad")

WARNING: The use and proper placement of dispersive electrodes is a key element in the safe and effective use of this Radiofrequency lesion generator, particularly in the prevention of burns. Read and follow Boston Scientific’s dispersive electrode instructions for preparation, placement, surveillance, removal and use of any dispersive electrode. It is recommended that dispersive electrodes be used that meet or exceed the requirements of EN60601-2-2.

WARNING: Use a Boston Scientific approved gel-pad dispersive electrode with at least 110 cm² conductive plate area to disperse and return RF current over as large an area as possible, and thus minimize heating effects at that electrode, and to avoid high current densities and resultant burns in adjacent tissue.

NOTICE: The ground pad should be placed in close proximity to the lesion site.

WARNING: Observe the dispersive electrode during lesioning for signs of excessive heating.

NOTICE: Use of an approved ground pad with a stainless steel RF Cannula may provide a galvanic potential (the “battery effect”) resulting in a single stimulation pulse at the time the TC Electrode is placed into an RF Cannula. This should be anticipated, and does not present any risk or danger to the patient.

WARNING: Skin burns can result from the improper use of Ground Pads, including, but not limited to, the following:

Use of Ground Pads with a conductive plate area less than 110 cm2.

Use of expired Ground Pads or Ground Pads with dried gel.

Ground Pads not placed on a well vascularized, muscular, convex area of patient skin.

Use on patient with peripheral vascular deficiency.

Reuse or repositioning of Ground Pad.

Ground Pad placement over scar tissue, inflamed skin, adipose tissue, bony prominences, metal prostheses, ECG electrodes and cables, pacemakers, and areas where fluid may pool.

Use of Ground Pad not in accordance with this G4 RF Generator Operator’s Manual.

Use of a needle as dispersive electrode since a needle may cause skin burns at the reference site due to high current densities.


WARNING: Never proceed in a temperature monitored procedure if the generator does not read body temperature before you begin delivering RF energy.

WARNING: Verify functional safety of the device before each use, using the guidelines detailed in this manual.

CAUTION: Prior to each procedure, inspect all cables, electrodes, RF Cannulae, and dispersive electrodes for damage. Check the integrity of the electrode and cable insulation for signs of damage. Such damage could lead to RF Current loss, heating, and burning at undesired locations. A signal of undesired RF Current loss is that unusually high RF Voltage, Current, or Power values are required to achieve a desired electrode tip Temperature.

General Usage

WARNING: To avoid unanticipated stimulation to the patient, do not cycle the generator power or turn the generator power on while the patient is connected to the generator.

WARNING: The output of any electrode may change when patient output is being delivered. Do not move electrode(s) or change electrode connections to the generator when patient output is being delivered to any electrode.

CAUTION: Avoid electrode tip Temperatures near and above 100°C, as they may produce focal boiling and charring.

CAUTION: Raise the electrode Temperature slowly, particularly with large electrodes. Displayed temperature lags behind the actual temperature due to the thermal mass of the electrode.

WARNING: The generator is capable of delivering a significant amount of output. Patient or operator injury can result from improper handling of the active electrode and dispersive electrode, particularly when operating the generator. During energy delivery, the patient should not be allowed to come in contact with metal parts which are earthed or which have an appreciable capacitance to earth. The use of antistatic sheeting is recommended for this purpose. Unshielded leads (active or return) should be positioned so that they cannot come into contact with the patient or other leads connected to the patient and so that they do not run parallel to nearby leads.

WARNING: To avoid accidental burns:

Skin-to-skin contact (for example between the arms and body of the patient) should be avoided, for example by insertion of dry gauze.

For surgical procedures where the high-frequency current could flow through parts of the body having a relatively small cross sectional area, the use of bipolar techniques may be desirable in order to avoid unwanted tissue damage.

The output power selected should be as low as possible for the intended purpose.

WARNING: Failure of the generator could result in an unintended increase of output power.

CAUTION: The physician should observe and record all Voltage, Current, Power, Temperature and Impedance readings at all times, including when using Auto Ramp or Automatic Temperature Control (“Set Temp” or “Max Temp, see Sections 7.1 & 8.1). This gives the physician a measure of parameter normalcy for a given procedure and electrode size. Any anomalously high Voltage, Currents, Impedance, or Power readings would be apparent and signal possible problems.

WARNING: Apparent low power output or failure of the equipment to function correctly at normal settings may indicate faulty application of the dispersive electrode or failure of an electrical lead. Do not increase power before checking for obvious defects or misapplication. Effective contact between the patient and the dispersive electrode must be verified whenever the patient is repositioned after the initial application of the dispersive electrode.

WARNING: Do not continue the application of RF if Temperature readings are erratic or do not rise a sufficiently rapid rate for the amount of RF energy applied. Erratic or sluggish Temperature readings may indicate a faulty cable connection, broken Temperature sensor of the electrode, loss of RF Power into an undesired location, an inability of the generator to control the Temperature or RF output of the electrode, or a misalignment of the temperature-sensing electrode tip with the uninsulated tip of the RF Cannula into which it is inserted.

NOTICE: Always have spare electrodes and cables on hand in case a problem arises with the first one during a procedure. Reuseable cables and accessories should be periodically tested.

WARNING: Any modification of the G4 Radiofrequency Generator done by unauthorized agents compromises the safety and efficacy of the equipment.

Mains Power

CAUTION: Make sure that the wall outlet voltage matches the voltage displayed on the Voltage Selector located on the rear of unit (100, 120, 220, or 240). If not, open the Fuse drawer, remove the Voltage Selector and rotate it to the proper voltage setting.

CAUTION: Disconnect all electrodes, ground pad, and associated cables from the G4 before turning the mains power on or off.

Electrical Safety and EMC

Warning: This equipment/system is intended for use by healthcare professionals only. This equipment/ system may cause radio interference or may disrupt the operation of nearby equipment. It may be necessary to take mitigation measures, such as re-orienting or relocating the RFG-4 (G4) or shielding the location.

Chassis Layout

WARNING: When connecting any non-medical peripheral equipment to this device, it must be ensured that the equipment combination meets the requirements of IEC 60601-1.

Electrode Setup Warnings and Guidelines

Review and adhere to these guidelines before turning on the electrode output:

  • Attach electrodes and/or a ground pad to the electrode output connections on the front panel (Section 2) as shown in the Electrode Setup screen’s “Settings Graphic” (Section 5).
  • Disconnect all electrodes and ground pads from output and/or reference connections marked with a red “X” in the Electrode Setup screen’s “Settings Graphic” (Section 5).

WARNING: Do not mix types and sizes of electrodes when delivering output to more than one electrode. All electrodes and their associated needles used in a multi-electrode configuration, including Bipolar configurations, should be identical.

WARNING: Do not deliver Pulsed RF output to any electrode whose active tip exposure is less 2 mm or whose diameter is less than 23 Gauge. The temperature response of such an electrode is too rapid for Automatic Temperature Control in Pulsed RF mode.

WARNING: Do not use the generator in a multi-electrode configuration with any electrode(s) whose active tip exposure is less than 2 mm or whose diameter is less than 23 Gauge. The temperature response of these electrodes is too rapid for Automatic Temperature Control of multiple such electrodes in Thermal RF and Pulsed RF modes.

WARNING: Do not move electrode(s) or change electrode connections to the generator when patient output is being delivered to any electrode.

WARNING: Do not place multiple electrodes too close together to create a large lesion when using a monopolar electrode configuration (i.e. Electrode Setup RF Type=Standard). Failure to comply can cause a lesion with unpredictable size and shape and may result in patient injury.

WARNING: Do not place two bipolar electrode pairs too close together when using Electrode Setup RF Type=Bipolar and Active Electrodes=4. Failure to comply can cause a lesion with unpredictable size and shape and may result in patient injury.

WARNING: Do not attach a ground pad to the generator or to the patient when using Electrode Setup RF Type=Bipolar. Both the ground pad and the reference electrodes (Electrodes 2 and/or 3) are at reference potential and will draw Current from the active electrodes (Electrodes 1 and/or 4). Failure to comply can cause a lesion with unpredictable size and shape and may result in patient injury.

Touch Screen Calibration

WARNING: Poor calibration of the touch screen may cause user input to be recognized incorrectly.


CAUTION: It is recommended the CB112-TC, the SKG Knob and the RFG-STP Test Pad be sterilized by steam autoclave.

The above parts may be sterilized in a Prevacuum Sterilizer at 132-135°C (270-275°F) for at least 4 minutes.

No other parts may be autoclaved.


WARNING: Electric Shock Hazard

There are no user serviceable parts inside the G4. To avoid electric shock, return the device to Boston Scientific for servicing.

Fuse Replacement

WARNING: Risk of fire. Fuse must be replaced as marked.

Adverse Events

Reported adverse events or complications for RF heat lesions procedures include, but are not limited to, the following: Temporary motor deficit, post-operative pain, skin burns. Refer to the instructions for use for electrode kits used with the generator for additional adverse events that have been reported for specific RF applications.