Learning Objectives:After participating in this continuing professional development activity, the provider should be better able to:
1. Identify appropriate candidates for endometrial ablation.
2. Describe patient counseling for risks of endometrial ablation and risk factors for failure.
3. Discuss selection of available technology for nonresectoscopic endometrial ablation in the office setting and optimal conditions for outpatient endometrial ablation.
Endometrial ablation is an attractive management option for many premenopausal patients with heavy menstrual bleeding as an alternative to medical therapy or hysterectomy. The goal of endometrial ablation is to reduce menstrual bleeding by local destruction of the endometrium. Resectoscopic endometrial ablation, although an effective treatment for heavy menstrual bleeding, requires specific hysteroscopic skills by the operator and carries the risk of fluid overload and electrolyte disturbances. Since the 1990s, the FDA has approved several nonresectoscopic endometrial ablation systems (often referred to as global endometrial ablation), which have short ablation cycles and require less user expertise with similar effectiveness compared with resectoscopic methods.1 Although patient satisfaction between resectoscopic and nonresectoscopic techniques seems to be equivalent, nonresectoscopic techniques are associated with shorter operative times and are more often performed under local anesthesia.1 As such, they are much more feasible for use in the outpatient setting.
Success of endometrial ablation is primarily measured by patient satisfaction rates and rates of additional intervention including hysterectomy in the months and years after the procedure. It is therefore critical to properly identify candidates for endometrial ablation and counsel them regarding risk factors for dissatisfaction and for subsequent hysterectomy. This article aims to review available nonresectoscopic endometrial ablation systems, to identify ideal candidates for this procedure, to optimize success in the outpatient setting, and to describe risk factors for endometrial ablation failure.
Available Systems for Nonresectoscopic Endometrial Ablation in the United States
Per the Devices@FDA database, there are 9 proprietary systems approved for nonresectoscopic endometrial ablation in the United States2; however, only 5 are currently available on the market. Table 1 lists the characteristics according to the labeling documents for each device. All available systems can be used in the office or operating room settings with appropriate patient selection and counseling.
Patient Selection
The indication for nonresectoscopic endometrial ablation is heavy menstrual bleeding due to benign causes in premenopausal patients for whom childbearing is complete.3 Desire for future fertility is an absolute contraindication as abnormal placentation may occur in pregnancy subsequent to endometrial ablation. Patients should be counseled regarding appropriate contraception. Additional absolute contraindications include postmenopausal bleeding, endometrial hyperplasia or cancer, active urogenital infection, current pregnancy or desire for future pregnancy, and current intrauterine device use.2
Causes of Abnormal Uterine Bleeding
The International Federation of Gynecology and Obstetrics (FIGO) classification system (Table 2) delineates etiologies of abnormal uterine bleeding (AUB) into structural and nonstructural causes.4 The majority of patients who are ideal candidates for nonresectoscopic endometrial ablation fall under the category of AUB-endometrial (AUB-E), heavy menstrual bleeding related to endometrial dysfunction. This diagnosis is typically considered in patients with generally regular, heavy, or prolonged menstrual cycles after the exclusion of ovulatory dysfunction, coagulation defects, and structural causes.4
Part of proper patient selection for endometrial ablation is appropriate workup to exclude or consider other causes of AUB. The only FIGO subcategory of AUB for which endometrial ablation is absolutely contraindicated is AUB-malignancy (AUB-M), comprising endometrial hyperplasia and cancer. Endometrial sampling is required to exclude AUB-M in all patients planning to undergo ablation.3
No currently available systems have an explicit indication to treat intracavitary pathology. All currently available systems except the vapor system excluded patients with intracavitary or cavitary distorting leiomyomas, significant polyps, and evidence of adenomyosis in trials when seeking FDA approval.5-9 However, subsequent studies of particular systems have shown successful treatment for patients with intracavitary pathology (Table 1).10,11 Patients with these structural causes of AUB may still be candidates for endometrial ablation with appropriate counseling. Note that this use may be considered off-label.
Evidence is mixed on endometrial ablation effectiveness for patients with adenomyosis identified on ultrasound (AUB-A). Studies have demonstrated a high incidence of adenomyosis in hysterectomy pathology performed subsequent to endometrial ablation.12 Some studies have demonstrated adenomyosis as a risk factor for subsequent hysterectomy13 whereas others have not.14 Regardless of the presence of adenomyosis on ultrasound, significant dysmenorrhea has been identified as an independent risk factor for endometrial ablation failure.13,14
Patients with AUB related to ovulatory dysfunction (AUB-O) were excluded from pivotal trials involving endometrial ablation.5-9 Some experts advise against endometrial ablation, given the risk of development of endometrial hyperplasia or malignancy in the setting of anovulatory cycles. However, studies show similar effectiveness and patient satisfaction after endometrial ablation for patients with AUB-O.15,16 It should be noted that endometrial evaluation in patients after endometrial ablation may be challenging or impossible, which may contribute to risk for future hysterectomy in patients with recurrent AUB-O. Thorough patient counseling and shared decision-making are therefore essential. Patients with bleeding disorders, AUB-coagulopathy (AUB-C) were also excluded from initial trials, but more recent evidence reports that these patients undergoing endometrial ablation have similar complication and success rates and patient satisfaction scores as compared with patients without coagulopathy.17,18
Other Patient Selection Considerations
In addition to considering the patient category of AUB being treated, uterine cavity size requirements must be met to consider endometrial ablation. These vary slightly from system to system. The majority of current available systems have a minimum uterine cavity sounded length of 6 cm. Recommendations for maximum sounded length range from 10 to 12 cm (Table 1).
Prior uterine surgery is an additional consideration when counseling a patient about endometrial ablation. A history of one low transverse cesarean delivery does not exclude patients from endometrial ablation. However, patients with previous surgeries that could significantly weaken the myometrium such as multiple low transverse cesarean deliveries, classical hysterotomy, or transmural myomectomy are not candidates for endometrial ablation. A history of endometrial ablation is also listed as a contraindication in the labeling documents for these systems.2
Patient Counseling
Before performing nonresectoscopic endometrial ablation, patients should be counseled on the expectations and risks. The most common adverse effects for nonresectoscopic endometrial ablation are nausea/vomiting and uterine cramping. Additional major risks include uterine perforation, hemorrhage, hematometra, and infection. In a meta-analysis of randomized trials, risks of these major complications for nonresectoscopic methods ranged from 0.26% to 1.85%.1
Perhaps the most significant risk for a provider to address with patients considering endometrial ablation is the risk of failure of the procedure, and patient desire to proceed with hysterectomy as a result. The most common indications for hysterectomy after endometrial ablation are bleeding, pain, or a combination of the 2.19 Patient counseling before endometrial ablation is critical as normalization of menstrual flow is the goal. The pivotal trials for available nonresectoscopic systems reported amenorrhea rates ranging from 6% to 70%.5-9 As amenorrhea is not guaranteed with this procedure, patients who desire amenorrhea may instead consider hysterectomy as first-line therapy.
Several risk factors for hysterectomy after endometrial ablation have been identified in the literature. Multiple studies have identified younger age at the time of ablation as a major risk factor. Longinotti et al19 found that risk for subsequent hysterectomy after endometrial ablation for patients younger than 40 years to be 40.6%. Additional studies have shown that treatment failure in women younger than 45 years is about twice as likely as for women older than 45 years.12,20
Preoperative dysmenorrhea or pelvic pain itself is also an identified risk factor for hysterectomy after ablation.13,14 Adenomyosis has been suggested as a predisposing risk factor for failure of endometrial ablation, and has been found in hysterectomy specimens after endometrial ablation.12 Despite this, Thomassee et al14 did not find a correlation between adenomyosis diagnosed by ultrasound and treatment failure. Although the suggestion of adenomyosis alone by imaging and patient presentation is often combined with dysmenorrhea, evidence at this time suggests that suspicion of adenomyosis alone is not an independent risk factor for ablation failure.
A history of tubal sterilization has been found to be a risk factor for hysterectomy after endometrial ablation.13-15 Cyclic pain in this population may be due to incompletely ablated endometrium in the cornual areas that forms hematometra due to inability to drain through occluded fallopian tubes, referred to as postablation tubal sterilization syndrome. In addition, a history of cesarean delivery has been found to increase risk for hysterectomy after endometrial ablation, although the proposed mechanism of this is unclear.12,13
An additional consideration in patient counseling and procedure preparation is the type of device used for ablation, and potential associated success rates and risk of failure. The only head-to-head studies for comparison on systems currently on the market is between NovaSure and Hydro Thermablator (now renamed Genesys HTA). A double-blinded randomized controlled trial demonstrated that patients who received endometrial ablation with NovaSure had higher satisfaction and amenorrhea rates and lower reintervention rates than those who had received treatment with Hydro Thermablator.21 The relative risk for intervention hysterectomy between NovaSure and Hydro Thermablator was 0.49. These findings endured when patients were followed up at 4 to 5 years.22
Optimizing Endometrial Ablation in the Outpatient Setting
After appropriate counseling and consenting for endometrial ablation, with a clear understanding of reported risks for failure as outlined previously, various steps can be taken to optimize success of the procedure in general, and tolerability in the outpatient setting. Consideration should be given to endometrial pretreatment, cervical preparation, pain control, and device selection. Additionally, as with any office procedure, care should be taken within the clinical environment to decrease anxiety. This can be accomplished by dimming room lights, offering music, and being attentive to communication throughout the procedure.
Endometrial Pretreatment
Ablation of the endometrium has been shown to treat to a depth of 4 to 6 mm.23 Given the variation of endometrial thickness during the menstrual cycle, attention to endometrial thickness is prudent. Dilation and curettage (D&C) before ablation is not recommended for any currently available system.2 Per device manufacturer recommendations, pretreatment with medical thinning of the endometrium is recommended for the systems using cryotherapy, heated saline, and heated vapor whereas the radiofrequency systems do not require pretreatment (Table 1). A 2013 Cochrane review looked at the efficacy and safety of various medications or D&C to induce endometrial thinning before surgery for endometrial destruction. For nonresectoscopic methods, premedication was not found to provide increased efficacy of the procedure.24 Providers may consider device recommendations in combination with evolving evidence and engage in shared decision-making with patients when considering treatment to thin the endometrial lining before ablation.
Cervical Preparation
A different degree of cervical dilation is required for each endometrial ablation system (Table 1). Cervical preparation has not been studied specifically for outpatient endometrial ablation. Studies are mixed regarding the utility of misoprostol preadministration in outpatient hysteroscopy. The benefit of ease of dilation must be weighed against the risk of perioperative pain and bleeding, and potential side effects including nausea, emesis, and diarrhea.25 Difficulty with dilation may be less common in the premenopausal population undergoing endometrial ablation compared with postmenopausal counterparts. Individual consideration could be given to misoprostol administration before the procedure if cervical stenosis is suspected. Several dosing regimens and routes of administration have been proposed. Results from a 2016 meta-analysis on the use of misoprostol before hysteroscopy suggest a dose of 200 to 400 [mu]g vaginally as an optimal regimen to improve cervical dilation while minimizing side effects. The timing of single-dose administration varied widely between studies at 2, 4, 8, and 12 hours preprocedure.26 Providers should be aware that failure of cervical seal related to overdilation may jeopardize the ability to complete the treatment cycle.
Analgesia
Labeling documents for all systems recommend use of nonsteroidal anti-inflammatory drugs (NSAIDs) before procedure start and after procedure as tolerated and as needed. Marsh et al27 reported a study of patients undergoing endometrial ablation with or without preoperative analgesia with ibuprofen, which demonstrated that women who premedicated had a significant reduction in the rate of rescue analgesia and also a tendency toward less nausea. Although patients in this study did not receive any local anesthetic, 22 of 25 patients successfully completed the procedure.27
Several published protocols exist for local anesthesia for outpatient endometrial ablation. Options for introduction of local anesthetic include topical (to vagina or into endometrium) or injection (cervical, paracervical, or fundal). Due to the nature of uterine innervation, techniques to inject local anesthesia to both the cervix (innervated by sacral nerves) and the fundal area (innervated by T12-L2) have been proposed. Fundal blocks are achieved by hysteroscopic injection of local anesthetic to the fundus or cornual areas. A systematic review published in 2016 demonstrated greater improvement of pain scores during endometrial ablation with dual paracervical and fundal blocks than by paracervical block alone or without local anesthesia.28 However, other studies document procedural success with NSAIDs alone,27 and pain scores did not differ significantly from the studies that employed intra- and paracervical block.28
Procedure Tolerability
All nonresectoscopic systems may be offered in the outpatient setting with appropriate patient counseling. There are no head-to-head comparisons regarding tolerability of nonresectoscopic endometrial ablation systems as an outpatient procedure. In the pivotal trial for Cerene, 97.1% of the procedures were performed with paracervical block, oral pain control, or both, with all procedures successfully completed.5 Pain scores were considered at or below tolerability threshold for 92.1% of patients during treatment.5 With regard to the other systems, the majority of procedures during the pivotal trials were not performed under general anesthesia; however, there is no reported analysis of patients receiving IV sedation versus oral and local analgesics commonly available in the outpatient setting.6-9 Patient counseling, provider experience and comfort with the device being used, and device availability are all important considerations in procedure preparation and performance.
Conclusion
Endometrial ablation is a safe and effective management option for patients with heavy menstrual bleeding. Proper identification of candidates and counseling regarding risk factors for failure are important aspects of patient selection. Endometrial ablation is most readily achieved in the outpatient setting using one of the available nonresectoscopic self-contained endometrial ablation systems. Using evidence-based strategies for patient preparation and pain control gives patients the best experience during outpatient endometrial ablation.
Practice Pearls
* Candidates for outpatient endometrial ablation are premenopausal patients with heavy menstrual bleeding who have completed childbearing.
* Preoperative evaluation with endometrial sampling and evaluation of the endometrial cavity to evaluate for additional causes of AUB are recommended.
* Younger than 45 years is the greatest risk factor for hysterectomy after endometrial ablation.
* Additional risk factors for hysterectomy after endometrial ablation are dysmenorrhea and a history of cesarean delivery.
* Outpatient endometrial ablation is safe and well-tolerated.
* To optimize endometrial ablation in the outpatient setting, careful patient counseling, endometrial preparation, NSAID administration, and local anesthesia should be provided.
References