Device and method for detecting faults in a shielded instrument

A system for detecting insulation faults within a shielded electrosurgical instrument, comprising:

• an electrosurgical generator;
• an electrosurgical instrument having a shield;
• a device comprising:
• a battery power source;
• a monitoring circuitry configured to monitor electrical signals associated with the shield in the electrosurgical instrument;
• a control circuitry, responsive to the monitoring circuitry, configured to control a relay;
• wherein the monitoring circuitry comprises a envelope detector and a full wave rectified average detector generating a full wave rectified average value;
• the monitoring circuitry is further configured to generate voltages that are proportional to positive and negative shield current peaks, and to sum the voltages to generate an output voltage that is proportional to a shield current peak to peak value;
• wherein
• the battery power source is configured to power the control circuitry and the monitoring circuitry of the device;
• the device operatively coupled to an active connector of the electrosurgical generator and a return electrode connector of the generator;
• the device is operatively coupled to an active electrode and the shield of the electrosurgical instrument;
• the device is operatively coupled to a patient return electrode;
• and
• the monitoring circuitry, after the summing, is configured to at least perform one of:
• (a) the monitoring circuitry is configured to compare the shield current peak to peak value to a shield current peak to peak threshold value;
• the monitoring circuitry is further configured to compare a full wave rectified average shield current value to a detected full wave rectified average shield current threshold value;
• the device is configured to interrupt power to the electrosurgical instrument when either the shield current peak to peak exceeds the shield current peak to peak threshold or the detected full wave rectified average shield current exceeds the full wave rectified average shield current threshold value;
• (b) the device is configured to interrupt power to the electrosurgical instrument when a summation of the shield current peak to peak value and the detected full wave rectified average shield current value is greater than a summation shield current threshold value;
• or
• (c) the control circuitry comprises a resistor network, whereby the shield current peak to peak threshold value is variable, and the device is configured to interrupt power to the electrosurgical instrument when the detected full wave rectified average shield current value is greater than the variable shield current peak to peak threshold value.

A method for detecting insulation faults in a shielded electrosurgical instrument, comprising:

• connecting a device for detecting insulation faults in a shielded electrosurgical instrument to an electrosurgical generator, the device powered by an independent battery power source, the electrosurgical generator configured to deliver power to an electrosurgical instrument;
• coupling the device to a shielded electrosurgical instrument;
• monitoring set up signals of the shielded electrosurgical instrument, the set up signals including a connect sense and a battery power sense;
• monitoring electrical signals associated with a detected average shield current and a shield current peak and a detected full wave rectified average value;
• wherein monitoring electrical signals includes generating voltages that are proportional to positive and negative shield current peaks, and summing the voltages to generate an output voltage that is proportional to a shield current peak to peak value;
• comparing the electrical signals with threshold electrical signals;
• controlling alarm indicators;
• and
• after the summing, at least one of:
• (a) interrupting power to the electrosurgical instrument when either the shield current peak exceeds the shield current peak threshold or the detected average shield current exceeds the detected average shield current threshold value;
• (b) interrupting power to the electrosurgical instrument when a summation of the shield current peak value and the detected full wave rectified average shield current value is greater than a summation shield current threshold value;
• or
• (c) interrupting power to the electrosurgical instrument when the detected full wave rectified average shield current value is greater than a variable shield current peak to peak threshold value.