Myomectomy involves surgical removal of leiomyomas from their surrounding myometrium, and accepted indications include selected cases of abnormal uterine bleeding, pelvic pain, infertility, and recurrent miscarriage. Historically, removal of serosal and intramural tumors required laparotomy. However, laparoscopic excision may be performed by those with advanced skills in operative laparoscopy and laparoscopic suturing. Robotic myomectomy has also increased in popularity for this indication (Visco, 2008).
In general, removal of subserosal and intramural leiomyomas are most appropriate for a laparoscopic approach. Submucous leiomyomas are best treated via hysteroscopic resection. The choice of abdominal or laparoscopic myomectomy is based on various factors that include tumor number, size, and location. Surgical experience and comfort with laparoscopic dissection, tissue extraction, and suturing are other requisites.
Because of their impact on preoperative and intraoperative planning, leiomyoma size, number, and location are evaluated prior to surgery with sonography, MR imaging, and/or hysteroscopy, as described in Chapter 9. Specifically, leiomyomas may be small and buried within the myometrium. Therefore, accurate information as to tumor number and location ensures complete excision. Moreover, with a laparoscopic or robotic approach, the ability to palpate and appreciate smaller deep tumors may be compromised. In these cases, preoperative MR imaging may best assist with leiomyoma location and surgical planning. Last, multiple large masses or those that are located in the broad ligament, are near the cornua, or involve the cervix may increase the risk of conversion to hysterectomy, and patients are so counseled. Studies have also suggested that there is an increased risk of complications with the following: more than three leiomyomas, tumor size >5 cm, and intraligamental location (Sizzi, 2007). Accounting for these factors, a surgeon’s expertise is the most important factor in determining approach to myomectomy.
Myomectomy can cause significant bleeding that requires transfusion. Moreover, uncontrolled hemorrhage or extensive myometrial injury during tumor removal may necessitate hysterectomy. Patients are also counseled regarding the risk of conversion to an open procedure, which ranges from 2 to 8 percent (American College of Obstetricians and Gynecologists, 2014a).
Postoperatively, serosal adhesions can form and leiomyomas can recur. In some series, the risk of leiomyoma recurrence after laparoscopic myomectomy appears to be higher than in conventional myomectomy (Dubuisson, 2000; Fauconnier, 2000). As one explanation, with laparoscopic myomectomy, small, deep intramural leiomyomas may be missed because a surgeon’s tactile sensation is diminished.
The use of electrosurgical energy on the uterus and challenges of laparoscopic multilayer hysterotomy closure also heighten concerns regarding uterine rupture during a subsequent pregnancy (Hurst, 2005; Parker, 2010; Sizzi, 2007). Women undergoing myomectomy who do plan to have future pregnancies are counseled regarding the possible need for cesarean delivery based on the extent of myometrial disruption during the myomectomy.
Hematologic Status and Tumor Size
Many preparatory steps prior to myomectomy address associated patient anemia, anticipated intraoperative blood loss, and tumor size. First, many women who undergo this surgery are often anemic secondary to associated menorrhagia. Correction prior to surgery may include oral iron therapy, gonadotropin-releasing hormone (GnRH) agonist administration, or both. In anticipation of blood loss, a CBC and type and crossmatch for packed red blood cells is obtained. Autologous blood donation or cell saver devices may be considered if great blood loss is expected. In addition, uterine artery embolization may be performed the morning of surgery for large uteri to minimize blood loss. However, this is most often used prior to laparotomy for significantly sized uteri.
GnRH agonists may be considered to decrease leiomyoma size, lower intraoperative blood loss, and decreased adhesion rates. However, loss of pseudocapsule planes around the tumors and greater risk of recurrence due to missed smaller leiomyomas is the trade-off. A fuller evidence-based discussion of these same preoperative options is found in Section 43-10.
Few studies have addressed the benefits of preoperative antibiotic use. Iverson and coworkers (1996), in their analysis of 101 open myomectomy cases, found that although 54 percent of patients received prophylaxis, infectious morbidity was not lowered compared with patients in whom antibiotics were not used.
In cases of myomectomy performed for infertility, because of the potential for tubal adhesions associated with pelvic infection, antibiotic prophylaxis is commonly used. For those in whom prophylaxis is planned, 1 g of a first- or second-generation cephalosporin is appropriate (Iverson, 1996; Periti, 1988; Sawin, 2000).
The risk of bowel injury with this procedure is low, and bowel preparation is typically not required unless extensive adhesions are anticipated. Because the risk of conversion to hysterectomy is present, vaginal preparation immediately prior to surgical draping is performed. With laparoscopic gynecologic surgery, the decision to provide VTE prophylaxis factors patient- and procedure-related VTE risks (Gould, 2012). Thus, if longer operating times are anticipated or preexisting VTE risks are present, then prophylaxis as outlined in Table 39-8 is reasonable.
Many instruments required for laparoscopic myomectomy are found in a standard laparoscopy instrument set. However, a laparoscopic injection needle may be required for vasopressin injection, and a suction irrigation system is frequently needed to remove blood following tumor enucleation. A myoma screw or tenaculum is helpful to create needed tissue tension and countertension for enucleation. After tumor excision, removal may be accomplished by several techniques described on page 1031. Thus, required endoscopic bags or morcellators are assembled preoperatively.
Anesthesia and Patient Positioning
As with most laparoscopic procedures, the patient is placed in low dorsal lithotomy position in booted support stirrups after adequate general anesthesia has been delivered. A bimanual examination is completed to determine uterine size to aid port placement. Because of the risk of hysterectomy and because colpotomy may be used for tumor removal, both the vagina and abdomen are surgically prepared. A Foley catheter is inserted. A uterine manipulator may also be placed, including one that will allow chromotubation at the procedure’s end. If planned, indigo carmine or methylene blue dye is mixed with 50 to 100 mL of sterile saline for injection through the cervical cannula.
Trocar and Laparoscope Insertion
Primary and accessory trocars are placed as described in Chapter 41. Port placement is customized to assist uterine manipulation, leiomyoma excision, and hysterotomy repair. Depending on uterine height, the primary port may need to be placed supraumbilically. In general, a distance of at least 4 cm above the level of the fundus is helpful to provide a global view of the uterus. Typically, at least three accessory ports are required. If use of an electric morcellator is planned, one of the cannulas should be at least 12 mm to accommodate the morcellator. After the abdomen is safely entered, a diagnostic laparoscopy is performed, and the serosal uterine surface should be inspected to identify leiomyomas to be removed. Correlating with preoperative imaging, the surgeon selects the optimal uterine incision to minimize myometrial disruption and to remove the maximum number of tumors thorough one incision.
8-Arginine vasopressin (Pitressin) is a sterile, aqueous solution of synthetic vasopressin. It is effective in limiting uterine blood loss during myomectomy because of its ability to cause vascular spasm and uterine muscle contraction. Compared with placebo, vasopressin injection has been shown to significantly decrease blood loss during myomectomy (Frederick, 1994).
Each vial of vasopressin is standardized to contain 20 pressor units/mL. Suitable doses for myomectomy include 20 U diluted in a range from 30 to 100 mL of saline (Fletcher, 1996; Iverson, 1996). Vasopressin is typically injected along the planned serosal incision(s), between the myometrium and leiomyoma capsule (Fig. 44-8.1). A laparoscopic needle placed through one of the accessory ports or a 22-gauge spinal needle placed directly through the abdominal wall is suitable for injection. Needle aspiration prior to injection is imperative to avoid intravascular injection of this potent vasoconstrictor. The anesthesiologist is informed of vasopressin injection, as a sudden increase in patient blood pressure may potentially occur following injection. Blanching at the injection site is common. The plasma half-life of this agent is 10 to 20 minutes. For this reason, injection of vasopressin is discontinued 20 minutes prior to uterine repair to allow evaluation of bleeding from myometrial incisions (Hutchins, 1996).
The main risks associated with local vasopressin injection result from inadvertent intravascular infiltration and include transient increases in blood pressure, bradycardia, atrioventricular block, and pulmonary edema (Hobo, 2009; Tulandi, 1996). For these reasons, patients with a medical history of cardiac or pulmonary disease may be poor candidates for vasopressin use.
Because of postoperative adhesion formation risks, surgeons minimize the number of serosal incisions and attempt to place incisions on the anterior uterine wall. Tulandi and colleagues (1993) found for open myomectomy that posterior wall incisions result in a 94-percent adhesion formation rate compared with a 55-percent rate for anterior incisions.
After vasopressin injection, hysterotomy may be performed using a Harmonic scalpel, monopolar electrode, or laser. For most patients, an anterior midline vertical uterine incision allows removal of the greatest number of leiomyomas through the fewest incisions. The length should accommodate the approximate diameter of the largest tumor. The incision depth should afford access to all leiomyomas (Fig. 44-8.2).
Serosal incision overlying leiomyoma.
Once the hysterotomy is created, the myometrium will generally retract, and the first leiomyoma may be grasped with a laparoscopic single-toothed tenaculum. Alternatively, a leiomyoma screw can also retract tissue to create tension between the myometrium and mass (Fig. 44-8.3). Using a blunt tool or suction-irrigator tip, blunt dissection of the pseudocapsule surrounding the leiomyoma frees the tumor from the adjacent myometrium. Areas requiring sharp dissection from the myometrium may be freed with any of the electrosurgical instruments that were used for the uterine incision.
Hemorrhage during myomectomy primarily develops during tumor enucleation and positively correlates with preoperative uterine size, total weight of leiomyomas removed, and operating time (Ginsburg, 1993). Approximately two to four main arteries feed each leiomyoma and enter the tumor at unpredictable sites. For this reason, surgeons must watch for these vessels, coagulate them prior to transection when possible, and be ready to immediately fulgurate remaining bleeding vessels (Fig. 44-8.4). To avoid myometrial damage, the surgeon applies electrosurgical energy only when necessary.
Coagulation of vascular attachments between the leiomyoma and the myometrium.
Following removal of all tumors, redundant serosa may be excised. Laparoscopic suturing techniques described in Chapter 41 are used during incision reapproximation. The same general principles of myometrial closure for abdominal myomectomy are employed during laparoscopic myomectomy. In one method, for deep myometrial closure, a needle driver can be used with 0-gauge delayed-absorbable suture on a CT-2 needle in a continuous running fashion. Smaller internal myometrial incisions are closed first. The primary incision(s) is then closed in layers to improve hemostasis and prevent hematoma formation (Fig. 44-8.5). A gauge of sufficient strength to prevent breakage during muscle approximation is selected, typically 0 to 2-0 gauge. Alternatively, barbed sutures can close myometrial defects during laparoscopic myomectomy. These obviate the need for knot tying and yield consistent wound opposition (Einarsson, 2010; Greenberg, 2008).
Closure of the serosal incision using a running suture line with 4-0 or 5-0 gauge monofilament delayed-absorbable suture may help to limit adhesion formation (Fig. 44-8.6). Moreover, absorbable adhesion barriers have been shown to reduce the incidence of adhesion formation following myomectomy and may be introduced through laparoscopic ports (Ahmad, 2008). However, no substantial evidence documents that adhesion barrier use improves fertility, decreases pain, or prevents bowel obstruction (American Society for Reproductive Medicine, 2013).
Once amputated, the myomas must be removed, and options include minilaparotomy, colpotomy, and tissue morcellation. These are fully described in Section 44-10 and illustrated in Chapter 41.
Laparoscopically Assisted Myomectomy (LAM)
Another MIS technique that may allow for safe and efficient myomectomy is LAM. The procedure is initiated as described above, and abdominal cavity assessment, uterine inspection, and incision of the serosa and myometrium are performed laparoscopically. To aid in the laparoscopically challenging steps of myomectomy, LAM offers a hybrid approach. Specifically, tumor enucleation and uterine closure are completed through a 2- to 4-cm minilaparotomy incision placed suprapubically. With this, the pneumoperitoneum and visualization through the laparoscope are lost. Instead, application of a wound retraction system such as the Alexis or Mobius retractor provides visual access to the operative field. The uterus and leiomyoma are brought to the surface of the anterior abdominal wall and through the laparotomy incision. The tumors are then enucleated and divided through this incision (Fig. 44-8.7). This open incision also allows for conventional suturing techniques and aids suturing of large defects that require a multilayer closure (Fig. 44-8.8). Advantages include decreased operative time, technical simplicity, improved tactile sensation to detect deep intramural leiomyomas, and easier removal of very large tumors (Prapas, 2009; Wen, 2010). Disadvantages stem mainly from the larger abdominal wall incision.
Tumor enucleation during laparoscopically assisted myomectomy.
Myometrial closure during laparoscopically assisted myomectomy.
Following abdominal myomectomy, postoperative care follows that for any major laparoscopic surgery. Hospitalization typically varies from 0 to 1 days, and febrile morbidity and return of normal bowel function usually dictate this course (Barakat, 2011). Postoperative activity in general can be individualized, although vigorous exercise is usually delayed until 4 weeks after surgery.
Febrile morbidity of greater than 38.0°C is common following myomectomy (Iverson, 1996; LaMorte, 1993; Rybak, 2008). Purported causes include atelectasis, myometrial incisional hematomas, and factors released with myometrial destruction. Although fever is common following myomectomy, pelvic infection is not. LaMorte and colleagues (1993) noted only a 2-percent rate of pelvic infection in their analysis of 128 open myomectomy cases.
There are no clear guidelines as to the timing of pregnancy attempts following myomectomy. Darwish and colleagues (2005) performed sonographic examinations on 169 patients following open myomectomy. Following myometrial indicators, they concluded that wound healing is usually completed within 3 months. There are no clinical trials that address the issue of uterine rupture and therefore route of delivery of pregnancies occurring after myomectomy (American College of Obstetricians and Gynecologists, 2014a). Management of these cases requires sound clinical judgment and individualization of care. In general, large incisions or those entering the endometrial cavity favor cesarean delivery.