Available surgical techniques allow safe removal of even large fibroids. Use of tourniquets or vasoconstrictive agents may be used to limit blood loss. Vasopressin, an antidiuretic hormone, causes constriction of smooth muscle in the walls of capillaries, small arterioles and venules. Synthetic vasopressin (Pitressin, Parke-Davis, NJ) decreases blood loss during myomectomy and in a prospective, randomized study was as effective as mechanical occlusion of the uterine and ovarian vessels (116,117). Rare cases of bradycardia and cardiovascular collapse were reported; intravascular injection should be carefully avoided and patients should be carefully monitored (118). The use of vasopressin to decrease blood loss during myomectomy is an off-label use of this drug.
Cell savers may be considered for use during myomectomy. Use of the cell saver avoids the risks of infection and transfusion reaction, the oxygen transport capacity of salvaged red blood cells is equal to or better than stored allogeneic red cells, and the survival of red blood cells appears to be at least as good as transfused allogeneic red cells (119). The device suctions blood from the operative field, mixes it with heparinized saline, and stores the blood in a canister. If the patient requires blood reinfusion, the stored blood is washed with saline, filtered, centrifuged to a hematocrit of approximately 50%, and given back to the patient intravenously. Consequently, the need for preoperative autologous blood donation or heterologous blood transfusion often can be avoided (120). In a study of 92 women who had myomectomy for uterine size greater than 16 cm the cell saver was used for 70 women with a mean volume of reinfused packed red blood cells of 355 mL (121).
The cost of using a cell saver compared with donation of autologous blood was not studied for abdominal myomectomy. However, economic models suggest it is cost effective (121). Most hospitals charge a minimal fee for having the cell saver available “on-call” and charge an additional fee if it is used. Assuming that most women who donate autologous blood prior to myomectomy do not require blood transfusion, availability of the cell saver should spare many women the time and expense of donating, storing, and processing autologous blood. For a cohort of women, the cost of using the cell saver should, therefore, be significantly lower than the cost of autologous blood.
When heavy bleeding is anticipated or if copious bleeding is encountered, ligation of both uterine arteries can be performed (122). Uterine artery embolization was used successfully to control bleeding at the time of, or following, myomectomy (123). Because the uterine arteries recanulate, future fertility should not be compromised. These techniques often obviate the need for hysterectomy.
Uterine incisions can be made either vertically or transversely, because fibroids distort normal vascular architecture, making attempts to avoid the arcuate vessels impossible (124). However,
Figure 15.4 Corrosion casting of fibroid vessels.
careful planning and placement of uterine incisions can avoid inadvertent extension of the incision to the uterine cornua or ascending uterine vessels.
Based on vascular corrosion casting and examination by electron microscopy, fibroids are completely surrounded by a dense blood supply and no distinct vascular pedicle exists at the base of the fibroid (125) (Fig. 15.4). Extending the uterine incisions through the myometrium and entire pseudocapsule until the fibroid is clearly distinguished identifies a less vascular surgical plane, which is deeper than commonly recognized.