Radio frequency leakage current from unipolar laparoscopic electrocoagulators

Area of Science:

• Medical Devices
• Surgical Technology
• Electrosurgery

Background:

• Radio frequency (RF) leakage current is a suspected cause of accidental tissue burns during laparoscopic electrocoagulation for tubal sterilization.
• Unipolar laparoscopes are commonly used in these procedures, raising concerns about potential electrical hazards.

Purpose of the Study:

• To quantify the capacitively coupled RF leakage current from various unipolar laparoscopes.
• To assess the risk of tissue injury associated with measured leakage current levels.

Main Methods:

• Six unipolar laparoscopes from five manufacturers were tested.
• Leakage current was measured at different electrosurgical unit power settings (up to 150 W) into a 1,000-ohm load.
• Capacitance between the laparoscope body and forceps was also measured.

Main Results:

• Measured leakage current ranged from under 100 mA to over 550 mA, representing 24-62% of the total electrosurgical current.
• Leakage levels exceeding 400 mA, at power settings below 100 W in one device, can cause burns based on a tissue injury criterion of 100 mA/sq cm for ten seconds.
• Capacitance values varied between 53 and 140 picofarads.

Conclusions:

• Significant RF leakage current can occur with unipolar laparoscopes during electrosurgery.
• These leakage levels pose a risk of thermal injury to surrounding tissues.
• Device selection and careful surgical technique are crucial to mitigate burn risks.