Endometrial ablation, defined as the surgical removal or destruction of the endometrial lining of the uterus, is a commonly performed procedure for the treatment of heavy menstrual bleeding, with an estimated 25% of women in their child-bearing years experiencing abnormal uterine bleeding.¹

Background

Endometrial ablation, in some form, has been practiced for many years. The first ablation procedure documented was with chemical astringents to control a postpartum haemorrhage.² In 1898, Dührsen introduced steam into the uterus in an attempt to control heavy menstrual bleeding.³ This was noted to result in total atrophy of the uterus. The 19th century also saw electrosurgical techniques such as the use of a unipolar ball and fulguration being used, followed by radium in the early 1900s for treating both benign and malignant disorders.³

Cryoablation, the use of extreme cold to destroy tissues, was first documented in the 1960s.³ It was noted to persistently spare the cornual endometrium which limited its use. A neodymium yttrium-aluminium-garnet laser was introduced in the 1980s, and while this showed excellent depth penetration through the tissues, it was costly and preceded the modern fluid managing techniques, making this both inaccessible and unsafe at the time.³

The latter decades of the 1900s showed the use of continuous-flow resectoscopes, which gained increasing popularity.³ With this method came reports of morbidity and mortality related to fluid overload, prompting the development of non-resectoscopic methods of endometrial ablation. The year 1997 showed the first of these devices being introduced into the market, and currently there are at least six different types of second-generation (non-resectoscopic) endometrial ablation devices available globally.³

Indications and contraindications

The indications for endometrial ablation include the treatment of heavy menstrual bleeding in premenopausal women, which is usually ovulatory in nature.⁴

Prior to proceeding with endometrial ablation, it is important that the woman has an assessment of her endometrial cavity, review of the myometrial thickness (particularly if she has had previous uterine surgery such as a septum resection or caesarean section), and that endometrial sampling has been performed to exclude malignancy as a cause for her bleeding.⁴ She should also be counselled regarding alternative options for managing her abnormal uterine bleeding, risks of the procedure, expected outcomes and the need for reliable contraception ongoing.⁴

Table 1. Contraindications of endometrial ablation.⁴

Summary of methods of endometrial ablation

First generation endometrial ablation (resectoscopic endometrial ablation)

These methods are performed by resection or ablation of the endometrial lining under hysteroscopic guidance, and use resectoscopic electrosurgical instruments or laser. Techniques include electrosurgical desiccation with a rollerball, resection of the endometrium with a monopolar or bipolar electrode, radiofrequency vaporisation or laser vaporisation.⁵

These methods require specific operative hysteroscopic training and are not usually tolerated under local anaesthesia. They have the additional risks of longer surgical operating time, fluid overload risks and often require pre-operative hormonal suppression or treatment.⁵

Second generation endometrial ablation (non-resectoscopic endometrial ablation)

These methods are performed using a disposable device, which is introduced into the uterine cavity and delivers energy in a uniform manner to destroy the endometrial lining. There are multiple methods and devices available commercially worldwide, including:⁵

• Bipolar radiofrequency, eg. NovaSure®
• Thermal Balloon ablation/Hot liquid filled balloon, eg. ThermaChoice®, CavatermTM and Thermablate EASTM
• Cryotherapy, eg. Her Option®
• Circulating hot water, eg. Hydro ThermAblator®
• Microwave, eg. Microwave Endometrial Ablation
• Combined thermal and bipolar radiofrequency, eg. Minerva®
• Vapor ablation, eg. MaraTM

The most common non-resectoscopic methods used in Australia include bipolar radiofrequency and thermal balloon ablation.

Bipolar radiofrequency (Novasure®)

The bipolar radiofrequency device uses a mesh-covered disposable probe which is attached to a generator to deliver a radiofrequent current to the endometrium. This vaporises and coagulates the endometrium, as well as desiccating and coagulating the underlying superficial myometrium for up to 120 seconds.⁶ In addition, the device monitors carbon dioxide levels to assess for evidence of uterine perforation, and uses suction to remove debris and vapour throughout the procedure. The advantages of using bipolar radiofrequency for endometrial ablation includes the high rates of success with a reduction in bleeding at five or more years of 97-98% and amenorrhoea in 75–97%.⁷ Only 3–8% of women post ablation required a hysterectomy in this study. This method does not require preoperative treatment with medications such as Gonadotrophin receptor agonists or progestogens.⁵ The disadvantages include that this device has had limited research performed to assess the effectiveness of the device in the setting of submucosal or intramural fibroids extending into the endometrial cavity. Small studies suggest intracavity lesions less than 3mm are not associated with a reduction in efficacy or patient satisfaction.⁸

Thermal balloon ablation (CavatermTM)

This method is performed by placing a silicone balloon via an introducer into the endometrial cavity. The balloon is expanded to a pressure of 160–220mmHg with a fluid medium such as glycine and the fluid is then heated to 68–87 degrees Celsius for 8–10 minutes.⁵

Success rates for thermal balloon ablation are variable, with rates of reduced uterine bleeding of 22–81% and amenorrhoea in 23–58% of women at four years. These studies were performed on older devices, with current data demonstrating improved rates of bleeding or amenorrhoea of 74–83% and a 15% rate of hysterectomy with the most current model available in Australia.⁹ Disadvantages of this technique include increased postoperative pain when compared with other non-resectoscopic techniques, and discrepancies in the literature regarding the efficacy of this method in women with submucosal fibroids. This is related to the device requiring contact with the endometrium for ablation to occur. However, other studies have shown this method can be used in submucosal fibroids up to 3cm in size,¹⁰ highlighting the need for further research in this area.

Table 2. Comparison between first-generation and second-generation endometrial ablation techniques for the treatment of heavy menstrual bleeding.

Outcomes and efficacy

Both resectoscopic and non-resectoscopic methods of endometrial ablation have comparable outcomes in terms of amenorrhoea or reduction in menstrual blood loss at both one year and at 2–5 years. Studies performed are heterogenous in their assessment of how menstrual loss was measured and assessed. A Cochrane review in 2009 demonstrated rates of amenorrhoea of 37% vs 38% and 53% vs 48% in non resectoscopic and resectoscopic groups at one and two–five years respectively.¹¹

This meta-analysis also demonstrated equivalent patient satisfaction between the two types of endometrial ablation (91% in the resectoscopic group compared with 88% in the non-resectoscopic group) which persisted from one year to two–seven years, with similar rates of repeat surgical intervention for abnormal uterine bleeding found. Repeat surgical intervention rates following endometrial ablation is up to 25%, with the need for any type of surgery (hysterectomy included) at 21% for non-resectoscopic methods and 25% for resectoscopic methods. Rates of hysterectomy following ablation were demonstrated at 14% in the non-resectoscopic group and 19% in the resectoscopic group.¹¹

Complications of endometrial ablation

Pelvic infection is uncommon and can take the form of endometritis (1.4–2%), myometritis (0–1%), pelvic inflammatory disease (1.1%) and pelvic abscess (1–1.1%).⁵

Post ablation tubal sterilisation syndrome occurs in up to 10% of women following an endometrial ablation with a tubal ligation performed previously and is characterised by intermittent or cyclical pelvic pain.⁵ Suggested causes include contractures of the uterus with intrauterine scarring and/or trapped blood from active endometrium in the cornua. Diagnosis is guided by history, with MRI being useful for visualising blood in the cornua. Management is similar as for haematometra; dilation of the cervix, hysteroscopic guided adhesiolysis, laparoscopic excision of remaining portions of the fallopian tubes, or hysterectomy as definitive management.¹¹

Table 3. Complication rates for resectoscopic and non-resectoscopic methods of endometrial ablation.⁵

Conclusion

Endometrial ablation is an effective method for managing abnormal uterine bleeding. There are a variety of different approaches to performing an endometrial ablation, including both resectoscopic and non-resectoscopic methods. Non-resectoscopic methods involve less dedicated training in their use, shorter operating time and less serious complications, with no increased rates in the need for a hysterectomy or repeat procedure. Practitioners must have an awareness about the availability, benefits and limitations of each method when counselling patients with abnormal uterine bleeding.

1. Royal College of Obstetricians and Gynaecologists. National heavy menstrual bleeding audit. London: RCOG, 2014.
2. Wortman M. Endometrial Ablation: Past, Present, and Future Part I. Surg Technol Int. 2018;32:129-38.
3. Wortman, M. Late Onset Endometrial ablation failure. Case Reports in Women’s Health. 2017;15:11-28.
4. Royal College of Obstetricians and Gynaecologists elearning: Indications and Contraindications of Endometrial ablation. Available from: https://elearning.rcog.org.uk//uterine-cavity-surgery/endometrial-ablation/indications-and-contraindications
5. Laberge P, Leyland N, Murji A, et al. SOGC Clinical Practice Guideline: Endometrial ablation in the management of Abnormal Uterine bleeding. 2015;37(4):362-76.
6. Instructions for use: NovaSure Advanced Device. Available from: https://gynsurgicalsolutions.com/resource/
7. Fultop T, et al Novasure impedance controlled endometrial ablation: long term follow up results. Journal of Minimally Invasive Gynaecology. 2007;(14)1:85.
8. Sabbah R, Desauliers G. Use of the NovaSure Impedance Controlled Ablation System in patients with intracavity disease: 12 month follow up results of a prospective single arm clinical study. Journal of Minimally Invasive Gynaecological Surgery. 2006;13(5):467
9. Amso N, et al. Uterine endometrial thermal balloon therapy for the treatment of menorrhagia: long term multicentre follow up study. Human Reproduction. 2003;18(5):1082.
10. ACOG Practice Bulletin. Clinical management guidelines for Obstetricians and Gynaecologists- Endometrial Ablation. Obstetrics and Gynaecology. 2007;109(5):1233.
11. Lethaby A, Hickey M, Garry R, et al. Endometrial Resection/ablation techniques for heavy menstrual bleeding. Cochrane Database Systematic Review. 2009.