Development and use of a bipolar resectoscope in endometrial electrosurgery.

We conducted a prospective, blinded study to compare the tissue response and mechanical properties of a bipolar resectoscope with standard monopolar cutting and coagulation instruments. At the animal care facility of Tufts Medical School (Medford, MA), four surgeons blinded to instrumentation and distention media cut segments out of a rabbit uterine horn and desiccated the abdominal wall using either the bipolar device in 0.9% saline or the monopolar system in 1.5% glycine. Both systems used a Force 2 Valleylab radiofrequency generator at identical power settings. Cut and desiccated sections were fixed and stained with hematoxylin and eosin as well as Masson's trichrome to evaluate thermal damage. The pathologist was blinded to the system used to make the cut or desiccation. Both systems cut and coagulated tissue with similar properties. Most surgeons noted a longer delay from radiofrequency activation to actual cutting with the bipolar system. The depth of thermal damage when cutting or desiccating tissue was similar for the two systems. This disposable, inexpensive device allows for standard resectoscopic hardware to be transformed into a bipolar device. All current techniques of intrauterine cutting and coagulation may soon be performed in the presence of physiologic uterine distention media. Human clinical data remain to be gathered.