INTRODUCTION — Uterine leiomyomas (myomas or fibroids) are smooth muscle tumors and are the most common type of pelvic tumors in women. Myomectomy is removal of the myomas, while leaving the uterus in place.
Myomatous uteri have an increased number of arterioles and venules and myomectomy may involve significant blood loss [1]. However, studies show that the blood loss is no greater than for hysterectomy, when controlled for uterine size [2]. The average volume of blood loss during abdominal myomectomy (performed via laparotomy, also referred to as open myomectomy) is 200 to 800 mL [2-4] and for laparoscopic myomectomy is 80 to 250 ml [5,6]. Surgical hemorrhage may result in anemia, hypovolemia, and coagulation abnormalities.
Bleeding can be prevented or decreased with mechanical or pharmacologic methods. Allogeneic blood transfusion can be avoided by using methods of autologous blood transfusion (autologous blood donation, intraoperative and postoperative blood salvage, or acute normovolemic [isovolemic] hemodilution).
Techniques to reduce blood loss during abdominal or laparoscopic myomectomy are reviewed here. Preoperative and postoperative care and surgical technique for abdominal or laparoscopic myomectomy are discussed separately. (See "Abdominal myomectomy" and "Laparoscopic myomectomy and other laparoscopic treatments for uterine leiomyomas (fibroids)".)
VASCULAR ANATOMY OF THE UTERUS AND LEIOMYOMAS — The ascending blood supply of the uterus is from the uterine arteries, which pass through the cardinal ligament at level of the cervicouterine junction. The descending blood supply is from the ovarian arteries, which pass through the infundibulopelvic ligaments (suspensory ligaments of the ovary) and perfuse the ovaries, fallopian tubes, and uterine cornua (figure 1). The uterine and ovarian vessels anastomose to perfuse the uterus. Arcuate arteries run transversely within the uterine wall and radial arteries penetrate deeply into the myometrium [7].
The presence of leiomyomas in the uterus distorts normal vascular architecture [8]. Thus, the arcuate arteries may run in any axis, rather than transversely. Thus, either vertical or transverse incisions during myomectomy may transect these vessels. (See "Abdominal myomectomy", section on 'Uterine incision'.)
It has been the common teaching that there is a vascular pedicle at the base of each myoma, and that ligation of this pedicle will achieve hemostasis during myomectomy. However, a study using vascular corrosion casting and electron microscopy revealed that myomas are surrounded completely by a dense vascular layer supplying the myoma, which is separated from the myometrium by a narrow avascular cleft [9].
PREOPERATIVE MEASURES — Several preoperative measures can be taken to reduce the likelihood of postoperative anemia.
Correction of anemia — Iron deficiency anemia associated with menorrhagia or dietary deficiency is the most common cause of anemia in the gynecologic patient population. In women with abnormal uterine bleeding, a common symptom of uterine leiomyomas, laboratory testing for anemia should be part of the diagnostic evaluation. (See "Chronic menorrhagia or anovulatory uterine bleeding", section on 'Evaluation'.)
Preoperative anemia increases likelihood of blood transfusion and also increases the risk of perioperative morbidity and mortality. A systematic review of 20 observational studies confirmed the association between preoperative anemia and blood transfusion [10]. No meta-analysis was performed to quantify the magnitude of this effect, but in one representative study of 212 patients who underwent colorectal surgery, the rate of transfusion was significantly higher in those with a hemoglobin ≤12.5 g/dL compared with >12 g/dL (49 versus 19 percent) [11]. The effect of preoperative anemia on perioperative morbidity was illustrated in a retrospective study of 1958 patients who underwent noncardiac surgery and declined blood transfusion for religious reasons [12]. A preoperative hemoglobin of ≤10 g/dL was associated with a three-fold or higher increase in serious perioperative morbidity (cardiac events, respiratory failure, or serious bacterial infection) or mortality.
Preoperative anemia may be treated with iron supplementation. Strategies to correct anemia preoperatively are discussed in detail separately. (See "Management of hemorrhage in gynecologic surgery", section on 'Correction of anemia'.)
GnRH agonists — Preoperative use of gonadotropin releasing hormone (GnRH) agonists provides some short-term benefits for women undergoing myomectomy regarding blood loss and uterine size, but may increase the difficulty of surgery [13]. In the long-term, their use appears to increase the risk of persistent/recurrent myomas.
Preoperatively, GnRH agonists can help correct anemia by temporarily inducing amenorrhea [14,15]. However, the clinical impact of these agents is controversial. A meta-analysis of 11 randomized trials compared women planning abdominal myomectomy who were treated with a GnRH agonist for three to four months with those receiving either placebo or no treatment [13]. Preoperative GnRH agonist therapy resulted in a small, but statistically significant, increase in preoperative hemoglobin (1.0 g/dL higher). A further benefit of treatment with these agents was a reduction in intraoperative blood loss (68 mL less). Ultimately, however, there was no significant decrease in the risk of blood transfusion in women treated with GnRH (14 percent for both treatment groups; OR 0.86, 95% CI 0.26-2.85). This analysis was limited by insufficient statistical power to detect this difference.
Another potential benefit of GnRH agonists is reduction in uterine size. This may permit the use of a transverse rather than vertical laparotomy incision or may make a laparoscopic approach possible. (See "Abdominal myomectomy", section on 'Reducing uterine size with GnRH agonists' and "Laparoscopic myomectomy and other laparoscopic treatments for uterine leiomyomas (fibroids)", section on 'GnRH agonists'.)
There are several important disadvantages of preoperative use of GnRH agonists. These agents make enucleation of fibroids more difficult by obscuring the tissue plane between the myoma and the myometrium [16]. Operative difficulty associated with GnRH agonist pretreatment has been measured in only one randomized trial, which found no difference in difficulty between pretreatment with a triptorelin compared with immediate surgery [17]. In our experience, however, operative difficulty is noticeably increased after pretreatment with these medications.
There is concern that pretreatment with GnRH agonists may increase the risk of persistent myomas, because small myomas would shrink in size and would not be palpable during myomectomy. The meta-analysis described above reported a significantly higher rate of post-myomectomy myomas in women treated with GnRH agonists compared with placebo or no treatment (11 of 17 [65 percent] versus 7 of 25 [28 percent]; OR 4.0, 95% CI 1.1-14.7) [13]. The sample sizes and number of events in this analysis were small and the follow-up period ranged widely from 6 to 38 months. A subsequent randomized trial (n = 108) that compared eight weeks of triptorelin therapy with no treatment had a similar finding (proportion of women with myomas at six-month follow-up: 8 versus 2 percent) [17].
Most of the data regarding GnRH agonists and myomectomy are for open procedures. The only randomized trial to address this issue in women undergoing laparoscopic myomectomy found that GnRH agonist treatment compared with no treatment resulted in a significant increase in operative duration (45 minutes longer) and no decrease in blood loss [18]. (See "Laparoscopic myomectomy and other laparoscopic treatments for uterine leiomyomas (fibroids)", section on 'Conversion to laparotomy'.)
GnRH antagonists are another type of agent that suppresses endogenous GnRH. Their effects are similar to those of GnRH agonists, with the exception that results would be seen sooner, since GnRH is immediately suppressed. However, these agents are not widely used for a preoperative indication, since they are more expensive than GnRH agonists and require a daily injection. There are no high quality data regarding use of GnRH antagonists prior to myomectomy.
Treatment with either GnRH agonists or antagonists is accompanied by menopausal symptoms (eg, hot flashes, mood disturbance) that many women find difficult to tolerate.
In summary, there is no evidence that use of GnRH agonists prior to myomectomy reduces the risk of blood transfusion and such use may increase operative difficulty and the risk of myoma persistence/recurrence. The primary advantage of use of these agents is the ability to use a more favorable laparotomy incision or, potentially, to use a laparoscopic approach. We suggest not using GnRH agonist pretreatment for women undergoing open or laparoscopic myomectomy. Use of these agents is a reasonable option in women for whom treatment would allow a transverse rather than a vertical incision or a laparoscopic rather than open myomectomy and who place a high priority on type of surgical incision and/or duration of recovery.
Autologous blood donation — A patient who is scheduled for surgery and is not anemic may bank one or more units of her own blood. (See 'Autologous blood donation' below.)
INTRAOPERATIVE MEASURES — Bleeding can be prevented or decreased with mechanical or pharmacologic methods. Unfortunately, none of these interventions has been proven to reduce the rate of blood transfusion. Allogeneic blood transfusion can be avoided by using methods of autologous blood transfusion.
Pharmacologic interventions — Several pharmacologic agents reduce blood loss during myomectomy, although none has been proven to reduce the risk of blood transfusion. No studies have compared directly between these medications. Surgeons should use the agent with which they are most experienced, barring any individual patient contraindications. The most commonly used agent is vasopressin.
Vasopressin and other vasoconstrictors — Intramyometrial vasopressin injected into the planned uterine incision site for each fibroid reduces blood loss. Vasopressin acts by constricting the smooth muscle in the walls of capillaries, small arterioles, and venules. Randomized trial data show that blood loss during myomectomy with vasopressin is significantly less than with placebo (299 mL less [19]) and less than or comparable to use of a uterine artery tourniquet [20-22].
- Safe use of vasopressin - Vasopressin use during myomectomy has been associated with rare cases of bradycardia, cardiovascular collapse, and death [22-26]. Vasopressin use may be contraindicated in women with medical comorbidities (eg, cardiovascular, vascular, or renal disease). The use of vasopressin to decrease blood loss during myomectomy has not been approved by the United States Food and Drug Association.
Safe use of vasopressin depends upon the surgeon’s knowledge of its pharmacodynamics and use of safe practices. Care should be taken to avoid intravascular injection; before injecting, the surgeon should pull back on the plunger of the syringe to check for blood. However, complications may result even if intravascular injection does not occur. The maximal safe dose of vasopressin is not well established. Cardiovascular complications following intramyometrial injection have been reported in isolated cases with total vasopressin doses ranging from 5 to 11 units [23-25,27,28]. A classic prospective cohort study found no cardiovascular complication in 13 women undergoing myomectomy who received a maximum of 4 units of intramyometrial vasopressin [29]. An upper limit of a cumulative total vasopressin dose per procedure of 4 to 6 units has been proposed [30]. Use of a dilute solution helps to limit the total dose. In our practice, we dilute 20 units of vasopressin in 100 ml of saline; 4 to 6 units of vasopressin equals 20 to 30 mL of this solution. The half-life of intramuscular vasopressin is 10 to 20 minutes and the duration of action is two to eight hours.
There are few data about combining use of vasopressin with other measures. The only randomized trial to address this issue included 105 women who underwent laparoscopic myomectomy and were assigned to one of three groups: vasopressin combined with ligation of the myoma pedicle with a loop of suture, vasopressin alone, or no vasopressin or loop ligation [22]. Blood loss was significantly lower with combined use of vasopressin/loop ligation compared with vasopressin alone (59 versus 224 mL); both treatment groups had a significantly lower blood loss than the group that was not treated with either vasopressin or loop ligation (no treatment group: 364 mL). Ligation of the myoma pedicle merits further study.
Epinephrine is another vasoconstrictor that is effective in reducing blood loss during myomectomy. One randomized trial found that intramyometrial injection of bupivacaine with epinephrine (50 mL bupivacaine cloridrate 0.25 percent and 0.5 mL of 1 mg/ml epinephrine) reduced blood loss compared with saline (69 mL less) [27]. There were no differences in blood pressure or heart rate between groups. Intravascular injection of epinephrine may cause acute cardiovascular adverse events, similar to vasopressin. A disadvantage of epinephrine is that clinical experience during myomectomy is limited, since most gynecologic surgeons use vasopressin in this setting.
Uterotonics — Uterotonics have been used during myomectomy. One small randomized trial (n = 25) found that use of vaginal misoprostol (400 mcg, one hour before surgery) compared with placebo significantly reduced blood loss (149 mL less) [31]; further study of use of this agent during myomectomy is needed.
Data from a meta-analysis of two randomized trials including 77 women showed that intravenous oxytocin does not reduce blood loss compared with physiologic serum (mean difference in blood loss -69 mL; 95% -297 to 157) [19].
Other agents — Other agents to reduce blood loss during myomectomy have been investigated, but have not been found to be successful, including: tranexamic acid [32] and sodium-2-mercaptoethanesulphonate (mesna; used for chemical dissection) [33].
Topical hemostatic agents appear to reduce blood loss during myomectomy [34]. (See "Management of hemorrhage in gynecologic surgery", section on 'Topical hemostatic agents'.)
Tourniquets and clamps — Use of tourniquets and clamps that occlude the uterine blood supply reduce blood loss during myomectomy (figure 2). (See 'Vascular anatomy of the uterus and leiomyomas' above.)
The benefit of use of a uterine artery tourniquet was illustrated in a randomized trial of 28 women [35]. Use of a uterine artery tourniquet compared with no tourniquet resulted in a significant decrease in blood loss (an average of 1870 mL less). There are no high quality data regarding the use of infundibulopelvic ligament clamps.
Data conflict regarding whether tourniquet use is as effective as use of vasopressin. Blood loss with use of a uterine artery tourniquet compared with intramyometrial vasopressin was significantly lower in one randomized trial (an average of 225 mL less) [21], but was comparable in another trial [20]. There are no data regarding whether the combined use of a vasoconstrictor and tourniquets and clamps decreases blood loss more effectively than either measure alone. In our practice, we use vasopressin in all patients and reserve use of tourniquets and clamps for women with large fibroids.
An example of a procedure to apply a tourniquet is as follows:
- Palpate the broad ligament just above the level of the internal cervical os to identify a space that is free of vessels and the ureter.
- Make a 1 cm incision in this clear space bilaterally.
- Pass the tourniquet (eg, a Penrose drain [or a latex-free tourniquet in a latex-allergic patient]) through the incisions with the ends protruding anteriorly.
- Pull the tourniquet tight and secure by securing the ends with a Kelley clamp. Take care to avoid enlarging the broad ligament incisions or damaging surrounding structures.
Use of number one suture as a uterine artery tourniquet during laparoscopic myomectomy has been reported [35]. In general, however, it is difficult to secure a tourniquet using laparoscopic instruments.
Occlusion of the ovarian arteries is accomplished by placing a tourniquet or atraumatic vascular clamp (eg, bulldog clamp) bilaterally across the infundibulopelvic ligaments. Care must be taken to avoid lacerating the ovarian vessels or compressing the ureter.
There are no high quality data regarding the safe duration of tourniquet or clamp use to prevent uterine tissue damage. Some studies refer to releasing the tourniquet every 20 minutes, but outcomes for this practice have not been evaluated [21,35].
Autologous blood transfusion — Autologous blood transfusion methods include autologous blood donation, intraoperative or postoperative blood salvage, and acute normovolemic (isovolemic) hemodilution. There is no consensus regarding which method is most cost effective and acceptable to patients.
Autologous blood donation — Some surgeons advise patients to bank autologous blood, but this should be done only by patients with an appropriate hematocrit and sufficient time before surgery to avoid anemia at the time of surgery. Transfusion of banked autologous blood avoids some, but not all, of the risks that are associated with allogeneic blood transfusion. Transfusion of autologous blood should be restricted to the same indications as for allogeneic blood. (See "Preoperative autologous blood donation", section on 'Drawbacks' and "Preoperative autologous blood donation", section on 'Indications for transfusion'.)
Intraoperative blood salvage — In our practice, in procedures in which significant blood loss (≥300 ml) is anticipated, we use intraoperative blood salvage, if necessary. In a study of 91 women who underwent open myomectomy for uterine size greater than 16 weeks, the operative blood loss ranged from 50 to 3000 mL [3]. The Cell Saver® blood salvage was used for the 70 women with a blood loss ≥300 ml; 7 women received a homologous (non-autologous) blood transfusion in addition to blood salvage. The cost of using a cell-saver compared to donation of autologous blood has not been studied for abdominal myomectomy.
Normovolemic (isovolemic) hemodilution — There is only one report of normovolemic (isovolemic) hemodilution during myomectomy [36], but we have not used this approach in our practice.
Methods of autologous transfusion and their use in gynecologic surgery are discussed separately. (See "Preoperative autologous blood donation" and "Intraoperative and postoperative blood salvage" and "Acute normovolemic intraoperative hemodilution" and "Management of hemorrhage in gynecologic surgery", section on 'Autologous transfusion methods'.)
Other measures — Uterine artery ligation or embolization or internal iliac artery ligation may also be used to avoid hysterectomy when heavy bleeding is anticipated or occurs during myomectomy [37,38]. The uterine vessels will recannulate, so future fertility should theoretically be preserved. However, the impact on fertility and obstetric outcomes following uterine artery embolization as a primary procedure is not well established. For this reason, we reserve these techniques for situations in which other measures have failed and additional hemostasis is needed to avoid hysterectomy. (See "Management of hemorrhage in gynecologic surgery", section on 'Internal iliac artery ligation' and "Uterine leiomyoma (fibroid) embolization", section on 'Pregnancy after UFE'.)
CLINICAL APPROACH — There is no consensus about the optimal combination of preoperative or intraoperative measures to decrease blood loss or prepare for autologous blood transfusion. Few studies have compared among interventions. Also, most interventions have not been proven to reduce the risk of blood transfusion and/or avoid hysterectomy, the most important outcomes to patients.
Our approach is to employ basic methods for all procedures, and then use additional measures when significant blood loss (≥300 mL) is anticipated or occurs. Blood loss during myomectomy is correlated with the size and number of myomas, and also with operative duration, (which depends in large part upon the first two factors) [20]. During the preoperative evaluation of each patient, we assess the characteristics of the myomas and make our best clinical estimate of the risk of excessive blood loss.
In our practice, for all women undergoing myomectomy, we do the following:
- Correct preoperative anemia.
- Inject vasopressin before each uterine incision.
- Many surgeons apply a uterine artery tourniquet (for open myomectomy only) and ovarian artery clamps in all patients. In our practice, we reserve the use of tourniquets and clamps for women with large fibroids.
For women in whom we anticipate significant blood loss (≥300 mL), we additionally do the following:
- Prepare for the use of blood salvage.
Preoperative banking of autologous blood is also an option, but should be limited to patients in whom this will not result in anemia at the time of surgery.
SUMMARY AND RECOMMENDATIONS
- Women with leiomyomatous uteri have an increased number of uterine arterioles and venules and myomectomy may involve significant blood loss. The average volume of blood loss during abdominal myomectomy is 200 to 800 mL and for laparoscopic myomectomy is 80 to 250 ml. (See 'Introduction' above.)
- We suggest not using GnRH agonist pretreatment for women undergoing abdominal or laparoscopic myomectomy (Grade 2B). Use of these agents is a reasonable option in women for whom treatment would allow a transverse rather than a vertical laparotomy or a laparoscopic rather than abdominal myomectomy and who place a high priority on type of surgical incision and/or duration of recovery. (See 'GnRH agonists' above.)
- To reduce intraoperative blood loss for women undergoing laparoscopic or abdominal myomectomy:
- In our practice, in procedures in which significant blood loss (≥300 ml) occurs, we use intraoperative blood salvage. Preoperative banking of autologous blood is also an option, but should be limited to patients in whom this will not result in anemia at the time of surgery. (See 'Autologous blood donation' above.)
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