Endometrial Ablation for Heavy Menstrual Bleeding

Abstract

Endometrial ablation can be described as one of the great gynecological success stories. It has changed the management of heavy menstrual bleeding dramatically. The development of newer (second generation) endometrial ablative techniques has enabled clinicians to set up comprehensive ‘one stop clinics’ based on an outpatient service to treat heavy menstrual bleeding effectively without the need for general anesthetic or conscious sedation. This article describes the rationale and evidence for use of different endometrial auto-ablative systems along with relevant technical and clinical aspects. It also addresses the essentials of a successful approach to outpatient endometrial ablation along with discussion on risks, complications and contraindications of the procedure.

Rationale

Heavy menstrual bleeding (HMB) is a common gynecological problem affecting 20% of women of reproductive age [1,2]. For clinical purposes, HMB is defined as excessive menstrual blood loss which interferes with the woman's physical, emotional, social and material quality of life, and which can occur alone or in combination with other symptoms. Any interventions should aim to improve quality of life measures. While hysterectomy still remains the definitive surgical treatment for HMB, endometrial ablation in contrast is less invasive, associated with shorter hospital stay and recovery, significantly less pain and fewer complications [3–5]. Currently, there is a variety of endometrial ablation devices used worldwide, which are well-established alternatives to hysterectomy for the management of women with HMB [6].

The underlying principle of action of endometrial ablation is to achieve destruction of the entire functional endometrium, thus preventing cyclical endometrial regeneration and suppressing menstruation, thereby inducing amenorrhea. In practice, the entire endometrial surface is not removed and islands of endometrium remain functional, although menstrual blood loss is significantly reduced to a level acceptable to most women.

The ‘first-generation’ techniques include endometrial laser ablation (ELA), transcervical resection of the endometrium (TCRE) and rollerball endometrial ablation (RBEA), all of which require direct visualization (hysteroscopy) of the uterine cavity. Endometrial thinning agents are conventionally used prior to ablation in order to ensure an adequate depth of destruction. Drugs such as danazol and gonadotropin-releasing hormone analogs (GnRHa) have been shown to improve operating conditions for the surgeon and increase postsurgical amenorrhea rates. These techniques have been extensively evaluated against the gold standard hysterectomy and shown to be effective, minimally invasive alternatives to control HMB with fewer complications [7,8]. However, these techniques require significant operator expertise and firmly remain in-patient techniques due to practical and safety issues.

‘Second-generation’ devices such as thermal balloon endometrial ablation (TBA), microwave endometrial ablation (MEA), hydrothermablation (HTA), bipolar radiofrequency endometrial ablation (RFA) and endometrial cryotherapy achieve deep endometrial destruction without the need for hysteroscopic surgical skills, so that visualization is no longer a prerequisite for endometrial ablation [9]. The automated design of these devices has opened the door for operating in the outpatient setting under local anesthetic, thus expanding patient choice and potentially increasing cost–effectiveness of treatment [10].

Effectiveness

The efficacy of all second-generation endometrial ablative devices is directly comparable with first-generation devices [11–15]. Satisfaction rates with the second-generation endometrial ablative devices are high, ranging from 77 to 96%, and compare favorably with first-generation ablation devices. Amenorrhea occurs in 14–70% [9,16] of women and quality of life including pleasure, habit and discomfort scores for women with HMB is substantially improved to a normal level 12 months after treatment with either first- or second-generation endometrial ablation [17]. The failure rates after endometrial ablation have been reported between 5 and 16% (hysterectomy or repeat ablation) [18–21].

Indications & patient selection

Endometrial ablative therapy is indicated in premenopausal women with HMB of benign etiology refractory to medical therapy and who have completed childbearing. An ideal woman undergoing endometrial ablation has a permanent method of contraception and regular HMB without significant dysmenorrhea. NICE [22] recommends that endometrial ablation should be considered in women with HMB who have a normal uterus and also those with small uterine fibroids (less than 3 cm in diameter). In women with HMB alone and with uterus no bigger than a 10-week pregnancy, endometrial ablation should be considered preferable to hysterectomy.

There is debate as to whether all focal intrauterine pathologies, such as submucous fibroids (SMFs) or polyps, should be hysteroscopically resected prior to endometrial ablation. Small polyps are likely to be treated at the same time as the global endometrial destruction. Significant cavity distortion by SMFs will affect optimal device seating with the exception of the HTA technology. Transcervical resection of such SMFs (TCRF) will be necessary and many gynecologists may wait to judge whether an improvement in HMB was achieved as a result, before considering subsequent EA. Other clinicians may proceed directly with EA immediately after TCRF; this appears to be safe for grade 0 SMFs, but where resection proceeds into the underlying myometrium there may be an increased risk of thermal injury and uterine perforation with concomitant EA.

All women undergoing EA should be advised about how the procedure is performed, its effectiveness and associated risks, ideally well in advance in the outpatient gynecology department (Box 1). Written information should be provided to these women. These women should be assessed to establish suitability of the procedure by undergoing examination, pelvic ultrasonography and endometrial biopsy (± hysteroscopy). Type of anesthetic, either general or local anesthesia, should also be discussed in advance.

Box 1.

Counseling for endometrial ablation.

• Discuss pros and cons of alternative medical and surgical treatment options

• Consider and discuss contraindications

• Counsel about the importance of contraception following endometrial ablation

• Describe what the procedure involves and the entire patient experience

• Discuss inpatient vs outpatient setting

• Inform about possible procedural and postprocedural side effects

• Inform about treatment outcomes; reduction in menstrual loss and satisfaction rates

As with any therapeutic intervention, there are contraindications to the use of endometrial ablation and these are discussed in Box 2. As the inclusion and exclusion criteria vary slightly for each particular ablative device, a clinician should consider these specific criteria provided by the device manufacturer.

Box 2.

Absolute and relative contraindications to endometrial ablation.

• Active genital tract infection

• Pregnancy or desire for future pregnancies

• Endometrial hyperplasia or cancer

• Previous uterine surgery, e.g., classical cesarean section, transmural myomectomy

• Uterine sound length >11 cm or <6 cm

• Irregular cavity with congenital defects

• Submucous fibroids with significant cavity distortion

Risks & complications

Despite the simplicity of the procedure, potential for procedure-related morbidity and reproductive complications exist. The Medicines and Healthcare products Regulatory Agency (MHRA) has recently published guidance on the responsibilities of manufacturers, the regulator and clinicians with respect to the safe endometrial ablation.

A nationwide audit [23] of more than 10,000 first-generation endometrial ablations from the UK found an overall complication rate of 4.4%. The most frequent complications were hemorrhage (2.4%), uterine perforation (1.5%) and cardiovascular and respiratory complications (0.5%). Emergency surgery due to perioperative complications was needed in 1.3% of patients. Rare, but major perioperative complications associated with mainly second-generation endometrial ablation (other than uterine perforation) reported to the US FDA Manufacturer and User Facility Device Experience (MAUDE) database have included bowel injury, necrotizing fasciitis, carbon dioxide embolism, urinary tract injury, severe burns, complications leading to hysterectomy or other major surgery, cardiac arrest and death (Box 3) [24].

Box 3.

Intraoperative and immediate postoperative complications.

• Serious (rare, require surgical intervention)

  • -Uterine perforation leading to intra-abdominal visceral or vascular injury
  • -Hemorrhage
  • -Hematometra

• Minor (self-limiting or easily treated)

  • -Cervical laceration
  • -Nausea and vomiting
  • -Pelvic pain/cramping
  • -Prolonged vaginal discharge

Clinicians performing endometrial ablation should be aware of the following long-term postsurgical complications [25].

Pregnancy after endometrial ablation

The incidence of unintended pregnancy after endometrial ablation is estimated to be 0.7% [26,27]. Although successful pregnancies have been reported after endometrial ablation, including those in amenorrhoeic women, there are increased obstetric risks. These include the increased risk of ectopic pregnancy, preterm birth, growth restriction, abnormal placentation (adherent placenta) and postpartum hemorrhage [28]. The risk of preterm birth and intrauterine growth restriction (IUGR) may be explained on the basis of compartmentalization or chambering of the uterine cavity postablation, resulting in a smaller area for the growing pregnancy. EA is not considered a method of contraception and the need for effective contraception following EA should be duly addressed.

Painful obstructed menses

Necrosis of the endometrial tissue and resulting inflammation can lead to intrauterine adhesions and uterine contracture following EA. Damage to the cervical canal during EA can result in central hematometra which presents as cyclic pelvic pain. The history of cyclic pelvic pain in conjunction with a pelvic ultrasound or MRI helps make the diagnosis. Cervical dilatation and/or hysteroscopic adhesiolysis could be effective treatments, but frequently hysterectomy is required to resolve severe cyclical iatrogenic pain. Retrograde menstruation from a cornual hematometra with blocked fallopian tubes (following sterilization) can result in cyclical pain with or without menses. This phenomenon has been labeled as ‘post ablation tubal sterilization syndrome’ (PATSS) and mostly presents as a delayed complication. The PATSS can be challenging to diagnose but an MRI may be helpful in making the diagnosis [25]. It is managed either by salpingectomy to remove the distended fallopian tubes, although more recent evidence suggests hysterectomy maybe a more effective alternative [29].

Treatment failure

Preoperative predictors of treatment failure include age less than 45 years, parity ≥5, prior tubal sterilization and a history of dysmenorrhea [18]. It is estimated that further surgical intervention, in the form of repeat EA or hysterectomy, may be necessary in 18–38% women undergoing EA [30] within the subsequent 5 years. Adenomyosis, intramural fibroids and hematometra are common pathological findings in women with EA failures. The authors have recently reported long-term clinical outcomes with 11 years (median 71 months) of post-treatment follow-up after TBA conducted in an outpatient setting under local anesthesia; 16% of patients required hysterectomy post-LA-Thermachoice to control their symptoms [31]. Repeat EA is often not feasible because of scarring and constriction of the uterine cavity nor indeed recommended in routine clinical practice in the absence of robust evidence supporting the safety and efficacy.

Infection

The reported incidence of infectious complications following EA such as endometritis (1.4–2.0%), myometritis (0–0.9%), pelvic inflammatory disease (1.1%) and pelvic abscess (0–1.1%) is generally low [25]. Although newer devices make EA a quick and minimally invasive procedure, the fact that it results in endometrial destruction and necrosis, increases the risk of infection and hence raises the question for need of a prophylactic antibiotic. A Cochrane review of prophylactic antibiotics for transcervical intrauterine procedures deemed there was no evidence to either support or discourage the use of antibiotics to prevent infection [32].

Types of devices

The second-generation ablation devices are much easier to learn and perform than first-generation devices. They usually do not require preceding endometrial pretreatment [33], are quicker to perform, are less costly and can usually be performed under local anesthetic. Therefore, patients can be treated in the outpatient or office setting.

These devices use a variety of energy sources to destroy the endometrium down to the basal layer to prevent regeneration and subsequent menstrual flow. Four of the more commonly used FDA and NICE approved second-generation devices are listed in Table 1. The choice between these second-generation devices depends upon many factors. Paramount among these factors is evidence of safety, reliability and effectiveness combined with other desirable qualities such as simplicity and suitability for outpatient operating.

Table 1.

US FDA-approved second-generation devices.

Endometrial ablation device	Duration of ablation (min)	Outpatient procedure suitability	Treatable cavity length (cm)	Treatable fibroid size (cm)	Safety measures
ThermaChoice balloon	8	Yes	6–10	≤2	Intrauterine pressure and temperature monitors
HerOption cryoablation	10	Yes	4–10	≤2	Ultrasound guidance
Hydro ThermAblator	10	Yes	<10.5	≤3	Direct hysteroscopic control
NovaSure	<2	Yes	6–10	≤2	Cavity integrity CO2 test

ThermaChoice thermal balloon ablation (Gynecare, Ethicon, Somerville, NJ, USA) achieves endometrial destruction by transferring the heat from heated liquid circulating within an intrauterine balloon [34]. The balloon is inflated with sterile 5% dextrose until the pressure is stabilized between 160 and 180 mmHg. The fluid within the balloon is heated to a preset temperature of 87°C. This system has undergone significant improvement from the first-generation Thermachoice (TBEA) to a third-generation Thermachoice III (TBEA-III) in 2003, with the key differences including replacement of the latex balloon with a compliant silicone balloon and introduction of an impeller device for active fluid circulation to enable equal heat distribution to entire endometrial surface area. The system continually monitors fluid temperature and intrauterine pressures and automatically deactivates at pressures <45 mmHg or >200 mmHg as a safety feature. The amenorrhea rates after TBEA are reported to be between 27% at 36 months [35] and 40% at 60 months [31,36]. This ablation technique has been studied in the outpatient setting [37,38]. The procedure completion rates range from 87 to 97% and the reported satisfaction rates with the procedure were in the range of 80–95% [31,35,39].

The Her Option uterine cryoblation therapy system (Cryo-Gen, Inc., CA, USA) achieves endometrial destruction by freezing the endometrium. The device consists of a cryoprobe in which pressurized gas (cryogen) is expanded through a small orifice to generate temperatures of −100°C to −120°C, creating an ‘ice ball’ within the endometrial cavity. Repositioning of the cryoprobe to create multiple ice balls is needed to ablate the endometrial cavity effectively. Both satisfaction and hypomenorrhea rates of 80% have been reported at 12 months [40].

The HydroThermAblator (Boston Scientific, MA, USA) achieves endometrial destruction by transferring the heat from heated 0.9% saline (90°C) circulating freely under low pressure within the uterine cavity [41]. A net intrauterine pressure of 50–55 mmHg is maintained, which is well below the hydrostatic pressure required for escape of the fluid through the fallopian tubes or the cervix (70 mmHg). Recirculating fluid volume is continuously monitored by the system and the procedure is halted if 10 ml of fluid is lost from the closed loop recirculation. The procedure requires cervical dilatation and exceeds 10 min in duration. Amenorrhea rate following Hydro ThermAblation ranges between 30 and 53% at 12–36 months after procedure [19,42]. The overall success rate is reported around 91% with 5.6% hysterectomy rate at 36 months follow-up [19].

NovaSure impedance-controlled radiofrequency ablation (Hologic, MA, USA) employs radiofrequency bipolar energy to ablate the endometrium (Figure 1).

Figure 1.

NovaSure® device.

The bipolar current generated by the device produces a tapered depth of ablation with shallower ablation in the cornual regions and lower uterine segment. A cavity perforation test must be passed before activating the electrode by insufflating the uterus with carbon dioxide and ensuring that the pressure can be maintained for 4 s. Mean endometrial ablation time is 90 s (range: 60–120 s). Amenorrhea rates following Novasure range from 30 to 97.1% at 6–84 months after procedure [5,42–45]. The patient satisfaction rates with the NovaSure range from 81.5 to 95.0%.

Outpatient endometrial ablation

Although different ablative techniques have their own individual nuances, the procedures are similar, so that the general approach is applicable to most second-generation ablative procedures. The author and associates use the following protocol for an outpatient endometrial ablation.

• All patients undergoing EA are advised to eat before the procedure to prevent hypoglycemia, dehydration and predisposition to vasovagal attacks. They are premedicated 1 h before the procedure with analgesics (diclofenac 100 mg oral/rectal suppository and two co-dydramol tablets orally [20 mg dihydrocodeine and 1 g paracetamol]) and an antiemetic (cyclizine 50 mg orally);

• During the procedure, every effort is made to keep the procedure room a relaxed and comfortable environment for the patient. A lithotomy position is used, and a healthcare assistant (HCA) acts as the woman's advocate during the procedure to provide reassurance, explanation and support. Communication with the woman in this way may help alleviate anxiety and divert their attention, thereby minimizing pain and embarrassment (the so-called ‘vocal local’). Two dedicated registered nurses are present to assist the clinician performing the procedure;

• A direct cervical block (DCB) is administered using 6.6 mls of 3% mepivacaine hydrochloride (Scandonest, Septodont, Ltd.) infiltration deep up to the level of the cervical isthmus level. A 35 mm, 27 G dental needle (Solosupra) is used to inject the cervix at 12, 3, 5, 6, 7 and 9 o'clock positions (‘direct local’);

• Cervical dilatation is performed in case the endometrial ablation device used requires this. A standard diagnostic hysteroscopy is then performed to exclude intrauterine pathology/anomalies distorting the uterine cavity and also excluding any evidence of false passages or uterine perforation caused by the cervical dilatation, which contraindicates proceeding with the procedure. Significant intrauterine polyps or fibroids are excised under direct endoscopic vision, if necessary. An endometrial biopsy is performed if no result is available within the last 6 months. The endometrial ablation is performed according to manufacturer's instructions;

• Postoperatively, women are moved to a designated recovery area. Additional simple analgesia such as 5–10 mg of morphine or NSAIDs is administered as required. The patient is discharged home after a minimum stay of 2 h and once she has tolerated oral diet. On discharge, the patient is given the ward's contact number in case of any problems. She is given analgesia to take home in the form of diclofenac or co-dydramol. No follow-up is specifically arranged and the patient is instructed to contact if she has heavy bleeding, pyrexia, severe abdominal pain or abnormal vaginal discharge.

Further considerations

Endometrial ablation & levonorgestrel-containing intrauterine system (Mirena, LNG-IUS)

The LNG-IUS is the most effective medical treatment for HMB [46] with the added benefit of effective contraception. It provides a nonsurgical alternative, which is reversible and fertility sparing. Therefore, women undergoing EA for HMB requiring contraception and who have above-mentioned preoperative predictors of EA treatment failure should be counseled to have the combined treatment with endometrial ablation and the LNG-IUS [47]. In the UK, guidelines from NICE recommend the use of Mirena in the first instance for women with benign HMB, followed by EA if pharmaceutical treatments fail to resolve symptoms. There is interest in the concomitant use of the LNG-IUS [48] to provide contraception, endometrial protection or enhanced treatment efficacy. A recent retrospective study assessing the effectiveness of combined EA and LNG-IUS therapy in patients with HMB and secondary dysmenorrhea reported significantly lower treatment failure rate at 4 years compared with EA alone [49]. However, further data are required before such an approach can be recommended in routine practice.

Inpatient versus outpatient setting

The pain experienced by women following endometrial ablation as an outpatient procedure under a local anesthetic is similar to those under general anesthesia. However, women undergoing the outpatient ablations experience less nausea and vomiting, spend less time in hospital and feel better following the procedure [50,51]. Compared with day-case procedures under general anesthesia, women undergoing outpatient procedures under a local anesthetic require significantly less time off work and experience reduced loss of income. This translates into economic benefits for women, the health service and society at large.

Most second-generation endometrial ablations can be performed as outpatient procedures under local anesthesia without formal theater facilities and minimal recourse to conscious sedation. Patients should be adequately counseled (Box 1) and offered a choice of both settings. Those patients at risk from general anesthesia (e.g., medical co-morbidities, obesity) should be appropriately counseled to opt for an outpatient alternative.

Pain control during outpatient endometrial ablation

Direct cervical or a paracervical block are commonly used local anesthetic techniques during outpatient ablations. However, it is well recognized that by this method alone, it is difficult to achieve complete uterine anesthesia, especially at the uterine fundus [52,53]. In our prospective cohort of patients (n = 213), who underwent EA with direct cervical (DCB) block only (between 2003 and 2011), the mean pain score (VAS) immediately after the procedure (both published and unpublished data) was 5.6 ± SD 2.6 [54]. Pain experienced during the outpatient procedure can be a disincentive and is the commonest reason for failure of completion of the procedure.

The uterine innervation is complex, in other words, the cervix and lower two thirds of the body are primarily innervated by the uterovaginal plexus, largely derived from the parasympathetic sacral (S1–S4) nerve roots, whereas the upper thirds of the uterine body is innervated by the thoracic nerves, largely derived from the sympathetic fibers of the superior hypogastric plexus (T8–T1 and L1 roots). The sympathetic innervation enters the uterus along the infundibulopelvic ligament and the path of the ovarian arteries. The standard cervical nerve blocks target the S1–S4 nerve roots but do not anesthetize the corpus effectively. Specific targeting of the nerve plexus around the cornua of the uterus with an additional intrauterine cornual block may result in improved anesthesia during outpatient EA. The authors have recently assessed the feasibility of such a block and suggested that a hysteroscopic fundal block in combination with a cervical block was more effective in relieving pain compared with a sole cervical block during EA [55]. The results of a placebo-controlled randomized controlled trial are awaited.

Conclusion

Endometrial ablation as a treatment for HMB has evolved significantly over the past couple of decades. It provides an acceptable, versatile and effective alternative to hysterectomy for the treatment of HMB. Outpatient HMB treatment should not be restricted to medical therapies, but should include EA in addition to hysteroscopic surgical interventions and placement of LNG-IUS devices. Hysterectomy may be the most cost-effective strategy, but, owing to its invasive nature and higher risk of complications, is considered a final option by gynecological experts and consumers who are swayed by other considerations such as ease of access to treatment, degree of invasiveness, long-term consequences and patient autonomy.

Future perspective

Endometrial ablation has changed the management of HMB dramatically. It has the potential to enable clinicians to set up comprehensive ‘one stop outpatient clinics’ to treat HMB effectively without the need for general anaesthetic and longer inpatient stay

Executive summary

• Endometrial ablation is an effective treatment for heavy menstrual bleeding refractory to medical therapy and provides patients with less invasive surgical alternatives to hysterectomy.

• The simple, safe and effective ‘second-generation’ auto-ablative systems have replaced traditional ‘first-generation’ hysteroscopic endometrial ablative methods.

• The design of second-generation systems along with short operating and recovery times has made operating in an outpatient hysteroscopy clinic setting feasible, expanding patient choice and health service capacity.