Endometrial Ablation

Anatomy and Physiology

Prior to performing endometrial ablation, it is important to evaluate the etiology of abnormal uterine bleeding to determine the correct management. There are many different causes of AUB, which can be classified by the acronym PALM-COEIN, a universally accepted nomenclature that was developed by the International Federation of Gynecology and Obstetrics (FIGO). There are structural causes of abnormal bleeding, including polyp, adenomyosis, leiomyoma, or malignancy. The non-structural causes of abnormal bleeding include coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not yet classified.[4]

A transvaginal ultrasound, saline infusion sonogram, or hysteroscopy are used to determine structural abnormalities and provide information on the size and position of the uterus. Non-structural causes of AUB can be due to endocrinopathies, underlying bleeding disorders such as von Willebrand disease, or iatrogenic causes, including various contraceptive methods or medications such as anticoagulants.[4] Endometrial hyperplasia or malignancy is an underlying cause of abnormal uterine bleeding and needs to be evaluated before an endometrial ablation with a histological sample of the endometrium.

The endometrial lining of the uterine cavity is composed of a functional and basal layer. The functional layer performs the physiologic functions of proliferation, maintenance of pregnancy, and menstruation, while the basal layer is implicated in regrowth of the functional layer.[5][6] The various endometrial ablation techniques destroy the endometrial lining, removing both the functional and basal layers.[7] By destroying these layers, the endometrium is no longer able to regenerate, thereby causing menstruation suppression.[2] After endometrial ablation, necrosis, fibrosis, and inflammation are common histology findings of the uterine cavity.[8]

Indications

Appropriate patient selection is important for the treatment of abnormal uterine bleeding with endometrial ablation. Candidates for endometrial ablation include women of reproductive age who have met their desired parity with heavy menstrual bleeding due to a benign cause that significantly impacts their quality of life. Further criteria should include AUB that is not related to a structural cause, hyperplasia or malignancy, and failure or intolerance of medical management. The ideal patient has AUB related to the endometrium as determined by the FIGO classification system and does not desire definitive management with a hysterectomy.[9][10] Lastly, the anatomy of the uterus is an important consideration, including the length of the cavity (no larger than 11cm) and contour of the cavity. This information can be obtained by a preoperative transvaginal ultrasound or saline infusion sonogram. Before performing an endometrial ablation, a benign endometrial biopsy must be obtained.

Contraindications

Contraindications to the procedure include:

• Pregnancy or fertility preservation
• Endometrial hyperplasia or uterine malignancy
• Active pelvic infection
• Intrauterine device
• History of transmyometrial uterine surgery including classical cesarean section or myomectomy
• Uterine anomaly such as septate, bicornuate, or unicornuate uterus
• Relative contraindications: postmenopausal state, uterine cavity length greater than 10 cm to 12 cm, severe myometrial thinning, or severe uterine retroflection or anteflexion[9][8]

Preparation

Prior to performing an endometrial ablation, it is important to discuss the patient’s expectations of menstrual bleeding after the procedure. The goal is to decrease the amount of heavy menstrual bleeding, therefore improving the patient's quality of life. Women who desire amenorrhea may not be good candidates for endometrial ablation. Amenorrhea rates were 15% to 72% 12 months after the procedure.[9] Counseling on future fertility and reliable contraception is necessary because pregnancy post-ablation carries high risks. As previously stated, one should evaluate the uterine histology with endometrial biopsy and anatomy, including size, position, and cavity contour with various ultrasound modalities before the procedure. Endometrial ablation is performed as an outpatient procedure, generally under anesthesia.

Technique or Treatment

Two techniques are described for endometrial ablation: resectoscopic and non-resectoscopic. Both techniques insert a device into the endometrial cavity and use different methods or energy to injury the endometrial lining.[8] 

First Generation Technique

Resectoscopic Endometrial Ablation

This technique is performed under hysteroscopic guidance using a rollerball, monopolar, or bipolar loop electrode. The endometrium is desiccated to the level of the basalis layer using thermal energy. The major disadvantage to resectoscopic endometrial ablation is operator expertise and safety.[7][2]

Second Generation Techniques

Nonresectoscopic Systems 

Many devices that do not require the use of a resectoscope are currently available to accomplish the destruction of the endometrium. The devices used are global and treat the whole endometrial cavity. Second-generation techniques include thermal fluid, microwave or bipolar radiofrequency electrical energy, laser thermotherapy, and cryoablation.[11] These options have become popular due to the ease of use, safety, and similar outcomes to resectoscopic techniques.[11]

Complications

Postoperative complications include:

• Distention fluid overload
• Infection
• Uterine trauma: including lacerations to the cervix, perforation of the uterus. With uterine perforation, there is the risk of injury to surrounding organs/structures or rarely fistualization
• Lower tract thermal injury: burns of the cervix, vagina, and vulva
• Pregnancy-related complications including premature birth, abnormal placentation, intrauterine growth restriction, malpresentation, and perinatal mortality
• Obstructed hematometra leading to cyclic pain due to residual endometrium 
• Post ablation tubal sterilization syndrome is seen in patients who had a prior bilateral tubal ligation and endometrial ablation. This syndrome is cyclic pelvic pain due to endometrial regrowth and distension of the uterine cornua with blocked fallopian tubes.
• Patient dissatisfaction with resulting menstrual bleeding
• Subsequent difficulty evaluating the endometrium due to scarring and changes seen on imaging after ablation can lead to missed or delayed diagnosis of uterine carcinoma.
• Reoperation with definitive hysterectomy within 5 years due to bleeding and/or pain[10][8][12]

Clinical Significance

Overall, most patients have a satisfactory outcome in treating heavy menstrual bleeding. In choosing a technique, both first and second generation are found to have equal efficacy in outcomes. At 12 months after a nonresectoscopic endometrial ablation, 82% to 97% of patients showed decreased menstrual bleeding, and 85% to 98% of patients were satisfied with their outcome.[9] However, there is a failure rate of 5% to 16% after 5 years of patients needing a repeat operation with definitive hysterectomy to treat persistent pelvic pain or bleeding.[2]

Compared to oral therapy: A meta-analysis included 12 randomized controlled trials of oral therapy versus surgical options for heavy menstrual bleeding. The results found that for those placed on oral therapy, 58% of women had surgery within two years. In comparing oral therapy to endometrial ablation, endometrial ablation was more effective in controlling heavy menstrual bleeding (at four months: RR 2.66 (95% CI 1.94 to 3.64); NNT = 2 (95% CI 2 to 3), one study).[13] 

Compared to Levonorgestrel intrauterine device (IUD): efficacy in decreased heavy menstrual bleeding were similar for those who received medical management compared to nonresectocopic endometrial ablation at two years.[9] Advantages to the IUD include non-surgical in-office application without anesthesia, fertility preservation, contraceptive, and superiority to oral medications.

Compared to Hysterectomy: Treatment with hysterectomy offers advantages such as amenorrhea and definitive management for heavy menstrual bleeding. Disadvantages of hysterectomy include increased hospitalization, complications, and recovery. A large Cochran review showed that repeat surgery due to treatment failure was more likely after endometrial ablation than after hysterectomy at one, two, three, and four years of follow-up.[14] 

Enhancing Healthcare Team Outcomes

Patient-centered care is important in the management of heavy menstrual bleeding. The literature emphasizes the improvement of quality of life in patients who undergo treatment for heavy menstrual bleeding with medical or surgical management. It has been found that women with HMB have a decreased quality of life equivalent to a loss of half a year of full health.[15] Gynecologists and midlevel providers encounter heavy menstrual bleeding daily in the clinical setting. It is important to strategize with the patient the best treatment option for quality of life improvement.

The minimally invasive surgical option of endometrial ablation in HMB needs to be considered a treatment option for women who do not desire hysterectomy. However, endometrial ablation is not without complications or failure. Studies have shown that endometrial ablation has similar efficacy and is more cost-effective to a hysterectomy in the short term, but with long term follow up women ultimately need definitive management with hysterectomy for persistent bleeding or pain to improve outcomes, proper patient selection, thorough preoperative evaluations including ultrasound and histological sampling, and realistic patient expectations need to be addressed before performing the procedure. Care coordination by physicians with preoperative and postoperative nursing, anesthesiology, radiology, and endometrial ablation device representatives is necessary for patient safety and overall team performance in the operating room.

A cohort study that looked at amenorrhea and treatment failure with EA found patient factors associated with poor outcomes. Patient factors that lead to treatment failure include age less than 45, parity greater than 5, prior tubal ligation, and history of pelvic pain. Factors that assist in amenorrhea include age greater than 45, uterine length less than 5, endometrial thickness less than 4mm, and use of radiofrequency ablation.[16] Models that help predict patient outcomes can guide physicians to enhance patient care, efficacy, and safety when offering endometrial ablation. [Level 3]

An interprofessional team approach to abnormal uterine bleeding cases, including those resulting in endometrial ablation, is necessary and will involve the primary care clinician, gynecological specialists, and nursing staff coordinating their activities and openly communicating to best guide successful patient outcomes. [Level 5]