It is important that the protocol at each institution be agreed upon by the chief of service and anesthesia as well as the director of nursing so that there are no conflicts at the time of surgery.
Uterine distention methods
Numerous methods have been used to distend the uterus: gravity, gas pressure, and electronic pumps and pressure bags. The optimal intrauterine pressure is the minimum pressure that allows for flow, distention, and visualization. Most of the time this ranges from 40 mm Hg to 60 mm Hg. The higher the intrauterine pressure, the more rapid the fluid intravasation, particularly when intrauterine pressure exceeds the mean arterial pressure.
Rapid fluid loss can occur even with low intrauterine pressures. That is because a large venous sinus will have a pressure of 8 mm Hg to 10 mm Hg, while the minimum uterine distention pressure is much greater. Strict adherence to fluid-deficit protocols will minimize the risk of complications from fluid overload.
Surgical technique
The goal of a hysteroscopic myomectomy is to alleviate symptoms without causing a weak myometrium or intracavitary synechia. Ideally, this is accomplished by completely removing the fibroid without traumatizing normal uterine tissue. Removal of the entire myoma reduces the likelihood of recurrence and regrowth.
Surgical technique for removal of Types 0, I, and II fibroids is illustrated and explained on (FIGURES1-4).
Within a given range (40 W to 100 W), it makes little difference which cutting-current setting on the RF generator you use; the principles are the same. The loop must be in contact with the tissue to be resected. Energy is applied and, once the circuit is completed (through tissue, the dispersive electrode, the generator and back to the loop), the loop is able to cut with minimal tactile feedback.
The lower the wattage, the more contact necessary between the loop and the tissue and the longer it takes to complete the circuit. Conversely, the higher the power, the faster the circuit is completed and cutting occurs.
Though it does not matter what setting is used, the operator must choose a setting based on his or her comfort level. Lower power gives the operator more control. Higher power should be used only by the most experienced hysteroscopist, since it involves very little tactile feedback and a higher risk of uterine perforation. At our teaching institution, we use 60 W of pure cutting current.
The technique for removing a submucous fibroid depends on its type and location within the endometrial cavity.
Type 0. Because these fibroids are pedunculated, the operator has the option of cutting the stalk (FIGURE 1) or shaving the myoma to remove it in pieces through the cervix. If the stalk is cut, it often is difficult to remove the fibroid through the cervix due to its large size. Nor can the fibroid be cut with monopolar energy because of the difficulty of completing the circuit. Type 0 myomas can be grabbed blindly with a Corson forceps or under direct visualization with an Isaacson optical tenaculum (Karl Storz Endoscopy, Culver City, Calif.). It also is acceptable to leave the fibroid in the cavity and let it degenerate and be expelled spontaneously. The risk of infection is very small.
My preference is to shave the fibroid down to the endometrium while it is attached to the stalk. I find it easier to remove when it is anchored rather than trying to pull out a single large specimen.
Type I. In a Type I myoma, more than 50% of the fibroid is within the uterine cavity, with a smaller portion embedded in the myometrium. To remove these fibroids, shave each to the level of the endometrium. To do so, place the loop behind the fibroid to be resected (FIGURE 5). Next, activate the RF energy using a foot pedal and, once the circuit is complete, draw the loop back into the resectoscope. Be careful to maintain visualization of the fibroid, loop, and cavity (FIGURE 6). This becomes difficult as the fibroid approaches the resectoscope and obstructs the hysteroscopic lens. To avoid this, bring the loop—which begins its cut fully extended—only halfway back to the resectoscope (FIGURE 7). Then retract the resectoscope itself, with the loop halfway extended, until the cut through the fibroid is complete (FIGURE 8). The loop then is retracted back into the resectoscope. The angle of the resectoscope must be adjusted to maintain loop contact with the fibroid tissue.
When more than 70% or 80% of the fibroid has been resected, the remainder will slough spontaneously over the next 2 to 4 months.