The menstrual cycle disorders have been classified as abnormal uterine bleeding (AUB) in the PALM-COEIN classification according to FIGO [1] [2] . They affect 15% of women [3] . It is a diagnosis of elimination in the absence of any organic cause [4] . In some cases, AUB can seriously disrupt a woman’s daily routine and even impair her quality of life [5] . In extreme cases, anemia or one of its complications can be life-threatening. Several treatments exist for the management of AUB: hormones (estrogens, progestins, LH-RH agonists, levonorgestrel intrauterine device), haemostatics (tranexamic acid) [6] . These therapies often fail, and more aggressive means such as surgery are used [5] [6] . In this case, a hysterectomy may be performed to be excessive, or the endometrium may be ablated: endometrectomy. Another conservative treatment option is thermoablation of the endometrium using the Novasure® procedure.

This device is often used at the Centre Hospitalier de l'Agglomération de Nevers (CHAN), France. It therefore seemed appropriate to describe the results of treatment of AUB with Novasure® thermoablation.

The study took place at CHAN, France. It was a descriptive and analytical study that ran from November 1, 2019 to December 31, 2022 (38 months). All patients diagnosed with AUB after ruling out an organic cause with a Higham score > 150 constituted the study population. Patients included in the study were those with AUB treated by endometrial thermoablation at CHAN. Incomplete files and patients who continued postoperative follow-up in another health facility were not included in the study. Prior to the Novasure® procedure itself, a diagnostic hysteroscopy was performed to visualize the uterine cavity and walls. Endometrial biopsy was then performed using a Novak cannula.

We were interested in the following variables: qualitative (profession, medical treatment received for AUB, favouring factors, endometrial histology, postoperative evolution), quantitative (age, parity, intraoperative uterine cavity measurements). It should be noted that all patients no longer wished to have children. We used the chi-square test to compare certain numbers at the = 5% threshold.

Description of the Novasure®

The Novasure® device is an endometrial vaporization system that emits radiofrequency waves. Treatment takes place in the outpatient operating room, with the patient anesthetized in the gynecological position, after sterile drapes have been applied in compliance with aseptic rules. A diagnostic hysteroscopy and endometrial biopsy are performed. Application of the deployed probe in the uterine cavity lasts an average of 90 seconds, with a maximum of 120 seconds. The ablation procedure terminates automatically when tissue impedance reaches 50 ohms, or after 2 minutes. A diagnostic hysteroscopy is then carried out again to verify the effective destruction of the endometrial surface layer. The endometrium appears charred. The procedure can be performed at any time during the menstrual cycle. No uterine distension is required. The main indications for Novasure® thermoablation are AUB, absence of desire for maternity and Highman score > 150. Contraindications are pregnancy or a patient wishing to become pregnant, endometrial carcinoma, history of Caesarean section or transmural myomectomy, active genital or urinary tract infections, intrauterine device, uterine cavity measuring less than 4 cm long or more than 6.5 cm, uterine cavity measuring less than 2.5 cm wide and more than 5 cm.

During the study period, we retained 156 patients with AUB, 17 of whom were treated with Novasure® thermoablation. This represents a frequency of 10.90% of patients with AUB requiring physical treatment by thermoablation.

AUB represent a pathology of hormonal imbalance. They are most frequently observed in premenopausal women, affecting 15% of patients over the age of 40 [3] [7] . AUBs can occur as a result of ovulatory dysfunction or coagulation disorders. In fact, the hormonal imbalance induced by pre-menopause favours an increase in pituitary hormones FSH and LH and a decrease in ovarian hormones. Histologically, this leads to simple glandular hyperplasia without atypia, induced by high FSH levels. These hormonal imbalances are not related to parity or occupation. In most cases of AUB, no favourable factors are found. However, in some cases, haemostasis disorders, ovarian dysfunction and dysthyroidism are risk factors [8] .

Gallinat’s study of 107 patients found failure of medical treatment to be the major indication for endometrial thermoablation using the Novasure® procedure [9] .

Procedure time was 2 minutes for uterine cavities wider than 5 cm (p = 0.01). In a study carried out on a cohort of 2,152 patients, Hui Xie et al showed that uterine cavity length (>10 cm) was significantly associated with lower efficacy of the Novasure® procedure for AUB management (p = 0.003) [10] . However, for normal uterine cavities that are neither too long nor too wide, treatment with Novasure® thermoablation is stable over the medium and long term [10] .

Comparison of endometrial thermoablation with the levonorgestrel intrauterine device showed that in 27% of cases, surgical treatment would be required to achieve the same result, i.e. reduction or cessation of AUB, compared with 10% for endometrial ablation (Relative risk 2.64; 95% confidence interval 1.49 - 4.68 [5] . Novasure® thermoablation is a minimally invasive technique with several advantages: it avoids hysterectomy, has a high success rate, no skin scarring, is fast, ambulatory, requires little or no interruption of professional activity, and causes little postoperative pain [11] . It is a procedure with a low incidence of serious complications compared with hysterectomy [12] - [15] .

Patient satisfaction has been demonstrated by the cessation of bleeding or at least a considerable reduction in menstrual flow [9] [16] . The isolated case of failure of the Novasure® procedure in our series was linked to a uterine cavity larger than 5 cm (p = 0.01). Our results show a high level of patient satisfaction (82.36%). A high satisfaction rate of 80% - 96% has been reported by other authors in cases of endometrial ablation [14] [17] - [19] . Some authors note adenomyosis as a factor in failure of Novasure® treatment [20] .

Despite its unquestionable efficacy, Novasure® thermoablation has its drawbacks, notably pelvialgia and postoperative leucorrhoea. The main factor limiting its widespread use is its high cost [21] . The generator is electronic, and the cannula with the electrode at its tip is a single-use device.

The Novasure® procedure is an effective way of overcoming AUB with very few complications. Thermoablation of the endometrium ensures immediate cessation of AUB, often with a marked improvement in quality of life. A large uterine cavity is a major factor limiting the effectiveness of Novasure® thermoablation. However, it is indicated for women over the age of 40 who no longer wish to procreate, in premenopause and without any organic cause. It is a second-line treatment after failure of medical therapy for AUB. The high cost of the device is the main factor limiting its widespread use.