The uterine resectoscope is similar to the one used in urology and is designed to apply radiofrequency electrical current to the endometrial cavity (Fig. 23.27). An understanding of the principles of electrosurgery is mandatory for safe and effective use of this instrument. By sliding the “working element,” one of a variety of electrode tips can be manipulated back and forth within the cavity. Tissue can be divided with a pointed electrode, excised with a loop, or desiccated with a rolling ball or bar. An electrode with multiple tips or edges can vaporize tissue, provided higher wattage generator outputs are used. A clear operative field is maintained by the continuous ﬂow of nonconductive distending media in and out of the cavity. Although basic design modifications made the resectoscope more useful in gynecology, extraction of resected fragments is time consuming. The most effective approach is the periodic use of a uterine curette or specially designed polyp or myoma forceps inserted after removal of the hysteroscope. Alternatively, much of the myoma or endometrium can be vaporized, thereby minimizing the need for periodic but time-consuming removal of tissue “chips.” If vaporization is used, it is important to obtain representative samples of the endometrium or myoma for pathological analysis.
Other Instrumentation For any hysteroscopic procedure, it is necessary to have available a cervical tenaculum, dilators, uterine curette, and appropriate-sized vaginal specula. When using the resectoscope, it is helpful to have a solid-state, isolated circuit electrosurgical generator capable of delivering both modulated and nonmodulated radiofrequency current. Laparoscopy or laparotomy may be necessary for emergencies secondary to uterine perforation.
Complications The potential risks of positioning a hysteroscopic system in the endometrial cavity solely for viewing (“diagnostic hysteroscopy”) are largely limited to cervical trauma and uterine perforation. Other adverse events such as infection, excessive bleeding, and complications related to the distention media are extremely uncommon when the procedure is short and does not involve instrumentation of the myometrium (0% to 1%) (199). The risks of operative hysteroscopy are related to one of five aspects of the procedure performed: (i) anesthesia, (ii) the distention media, (iii) perforation, (iv) bleeding, and (v) thermal trauma (198,199).
Anesthesia Local anesthetic protocols typically include the intracervical or paracervical injection of 0.5% to 2% lidocaine or mepivacaine solution, with or without a local vasoconstrictor such as adrenaline. Overdosage is prevented by ensuring that intravascular injection is avoided and by not exceeding the maximum recommended doses (lidocaine, 4 mg/kg; mepivacaine, 3 mg/kg). The use of a dilute vasoconstrictor such as epinephrine 1/200,000 reduces the amount of systemic absorption of the agent, virtually doubling the maximum dose that can be used and facilitates the onset of action of local anesthetic agents (220).