Endometrial ablation (EA) is a safe and efficacious endoscopic surgical procedure that has become a well-established alternative option in selected women with heavy and abnormal uterine bleeding [1]. In the United Kingdom, hysterectomy rates were significantly reduced over the past 20 years due to both improved medical treatment and increased use of EA techniques [2]. EA improves treatment access for those women who have abnormal uterine bleeding (AUB) and provides an alternative to radical procedures such as hysterectomy [3]. Hysterectomy was found to be associated with a higher risk than endometrial ablation of surgery for pelvic floor repair and stress urinary incontinence [3].

Despite the high success rate of endometrial ablation for uterine bleeding management, some patients experience persistent symptoms after the procedure, necessitating a hysterectomy. The characteristics of patients whose endometrial ablation fails had been studied by Kristin A Riley in a cohort study of 51 patients who had multiple variants assessed, including age, body mass index (BMI), parity and tubal ligation. The only statistically significant variant was age; it also revealed that endometriosis was the most common finding among patients who presented for hysterectomy after endometrial ablation; other findings included adenomyosis and leiomyomata [4]. Another retrospective cohort study of 968 women who had endometrial ablation between January 2007 and July 2009 compared the risk of treatment failure between women who had regular and irregular heavy uterine bleeding, concluding that preoperative bleeding pattern has no effect on failure rates or the need for gynecological procedures after endometrial ablation [5]. A study that included 128 women who had endometrial ablation or resection was conducted to determine the perioperative factors that influenced the success of this hysteroscopic intervention It was found that the presence of submucosal myoma was found to increase the risk of subsequent surgery [6].

The first-generation hysteroscopic techniques namely, roller ball ablation, bipolar endometrial resection and laser ablation, all required visualization of the cavity for the entirety of the procedure [7]. Second generation techniques have been developed which do not require hysteroscopy and can be easily performed without requiring high levels of skill include bipolar radiofrequency, microwave and thermal balloon ablation, endometrial cryotherapy, and hydrothermal ablation [8].

The success of endometrial ablation was seen in 80.6% of cases [9]. On the other hand, failure rates of endometrial ablation, which were manifested as persistence of pain or bleeding, have reached 10–20% that required patients to undergo further interventions to handle their malady [10].

The objective of our study was to determine additional patient characteristics and the clinical predictive factors of failure of endometrial ablation and the need of subsequent gynecological procedure.

The primary outcomes were to determine the pre-operative clinical predictive factors of failure of endometrial ablation in the management of uterine bleeding. Secondary outcomes were to search for any intra-operative predictive factors of failure of the procedure. Better understanding of the predictive factors of success or failure will help in proper counselling of patients and in decreasing the incidence of endometrial ablation failure and avoid further re-ablation or hysterectomy.

In total, there were 138 procedures were done in the study period. Ninety-five patients were included in this study; the age ranged from 29 to 52 years, with a mean age of 46.13 $\pm$ 7.11 years. Among the participants, the mean BMI was 29.97 $\pm$ 6.23, ranged from 18 to 56. Participants were categorized into two groups according to their failure or success of the primary endometrial ablation. Overall, 24.2% (n = 23) had a failed endometrial ablation with a subsequent gynecological procedure and 75.8% (n = 72) had a successful endometrial ablation with no further procedures required. Tables 1,2 show a comparison between patients with successful and those with failed endometrial ablation groups.

Our results showed a significant difference between patients with successful and failed endometrial ablations in regard to fluid deficit (p = 0.002) and blood loss during the surgery (p = 0.047); however, the age, BMI, parity, number of miscarriages, number of cesarean sections, uterine length, endometrial thickness and procedure duration had no significant difference between the two groups (p $\mathrm{>}$ 0.05). Table 1 shows the details of the successful and failed endometrial ablations.

There was no significant relationship between the uterine abnormalities in general and the outcome of the endometrial ablation (p = 0.637); however, there was a statistically significant, moderate association between adenomyosis and the outcome of the endometrial ablation (p = 0.003, $\phi$ = 0.37) and were more likely to have a failed endometrial ablation COR = 19.38, 95% CI, 2.11–177.73) (Table 2). In addition, patients with combined adenomyosis and dysmenorrhea had a statistically significant association with the outcome of the endometrial ablation (p = 0.016, $\phi$ = 0.28) and were more likely to have a failed endometrial ablation (COR = 4.67, 95% CI, 1.35–16.09).

Menorrhagia and heavy irregular menstrual bleeding were among the most common indications for endometrial ablation in 37.9% and 32.6% of the patients, respectively. Moreover, the patients who underwent endometrial ablation due to fibroids (17.9%) had a significant weak relationship with the outcome of the endometrial ablation (p = 0.26, $\phi$ = 0.25), they were more likely to have a failed endometrial ablation (COR = 3.73, 95% CI, 1.24–11.29). Other indications included irregular vaginal bleeding, polyps, postmenopausal bleeding, and infertility and they no longer sought pregnancy and would only treat their heavy periods.

We also found that patients who had both adenomyosis and dysmenorrhea were at higher statistically significant risk to have ablation failure than those with adenomyosis alone, p value = 0.016, 95% CI, 1.51–50.69 and p value= 0.003, $\phi$ = 0.37, respectively.

Overall, 24.2% had a failed endometrial ablation and had to undergo an additional procedure to alleviate the symptoms. The most common were repeated hysteroscopic ablation and hysterectomy, in 15 and 11 patients, respectively (Table 3).

In order to account for any confounding effects, the variables having significant associations at the p 0.1 level from the univariate analysis were included in the logistic regression model. These were the uterine length in weeks, fluid deficit, blood loss, diagnosis of adenomyosis, heavy menstrual bleeding and fibroid(s). The significant predictors for endometrial ablation failure were adenomyosis (AOR = 50.83, 95% CI, 3.64–706.75, p = 0.003) and fluid deficit (AOR = 1.003, 95% CI, 1.000–1.006, p = 0.044). The uterine length in weeks, blood loss, indication for primary endometrial ablation being heavy menstrual bleeding, or presence of fibroid were not significant predictors in the regression model, which had a Pseudo Nagelkerke R Squared of 0.49. Table 4 demonstrates the regression model results for an endometrial ablation failure prediction.

The overall success rate of our endometrial ablation procedures using the firstly generation rollerball ablative technique, REA, was very much good, acceptable and very helpful in a third world country with limited resources. When compared with hysterectomy, the treatment of AUB with endometrial ablation has been associated with reduced operative time, decreased morbidity, and cost effectiveness [13, 14].

Over half of patients treated with microwave endometrial ablation (MEA) achieved amenorrhea, and the procedure was suitable for women with myomas and irregular uterine cavities and the success rate of MEA at 12 months (87.0%; 95% CI, 81.7%–91.2%) did not differ significantly (p = 0.40) from that of REA (83.2%; 95% CI, 74.7%–89.7%) [15].

Our study showed an overall failure rate of 24.2%. All patients were operated upon using either general or spinal anesthesia with no reported serious complications like perforation, bleeding or significant fluid absorption. When second-generation versus first-generation techniques were compared, there was no evidence of differences in amenorrhea at 1 year and 2 to 5 years’ follow-up and there was subjective improvement at 1 year follow-up based on a Pictorial Blood Assessment Chart (PBAC) [16]. Moreover, patient satisfaction was not different between second- and first-generation techniques at 1 year, 2 years and 5 years’ follow-up. Second-generation ablation techniques were associated with shorter operating times and more often were performed under local instead of general anaesthesia [16]. There was uncertainty whether perforation rates differed between second- and first-generation techniques [16]. Trials reported little or no difference between second- and first-generation techniques in requirement for additional surgery (ablation or hysterectomy) at 1 and 5 years’ follow-up [16]. These findings support our practice in using first generation ablation as newer generations (second and third) are expensive and not readily available in our country. Similarly, levonorgestrel intra-uterine system (LNG-IUS) is still expensive in Jordan and not covered by many medical insurance companies. In a meta-analysis in 2020, endometrial ablation and LNG-IUS were found to be two excellent treatment options for heavy menstrual bleeding, although women treated with the LNG-IUS were at higher risk of experiencing side effects compared to women treated with endometrial ablation/resection [17]. This is very encouraging to us to further implement endometrial ablation in our practice taking into consideration the global and, particularly, the local economic restrictions. Similarly, in a review, when compared to endometrial ablation, it was not clear whether the LNG IUS offered any benefits with regard to reduced heavy bleeding while satisfaction rates and quality of life measures were found to be similar. In the same review, some minor adverse effects were more common with the LNG IUS but it appeared to be more cost effective than endometrial ablation techniques [18]. Hysterectomy was found to cause serious complications for a minority of women and most women might be well advised to try a less radical treatment as first-line therapy and it was found that both LNG-IUS and conservative surgery (ablation/resection) appeared to be safe, acceptable and effective [19]. Unfortunately, there were no studies in Jordan that compared these different modalities regarding particularly cost-effectiveness and patient satisfaction. There is an ongoing a multicenter randomized controlled trial to evaluate if the combination of endometrial ablation and an LNG-IUS is superior to endometrial ablation alone in terms of reducing subsequent rates of hysterectomy at two years following the initial ablative procedure [20].

Our study found a significant association between greater operative blood loss and fluid absorption (fluid deficit), as independent factors, with endometrial ablation failure. The presence of adenomyosis and uterine fibroids as indication of endometrial ablation was also found to be significantly associated with the outcome of the endometrial ablations. However, the patient’s age, BMI, parity, miscarriage, previous cesarean sections, uterine length (in weeks), endometrial thickness (in millimeters mm), dysmenorrhea and procedure duration (minutes) were not found to influence the effectiveness of the procedure. Some but not all of these findings were consistent with previous studies. Previous Cesarean delivery was not associated with an increased risk of failure of endometrial ablation, but dysmenorrhea, a submucous myoma and longer uterine depth are [21]. Their definition of failure was those patients who had ablation and hysterectomy. In our study, we did not specify hysterectomy as the only destination for failure definition. Moreover, dysmenorrhea cases in our study were only seven in both failed and successful cases. This low number might have influenced the statistical result.

We had a total of 6 cases of adenomyosis who had ablation; one was successful while the remaining 5 were a failure. There was no statistically significant difference in the outcome in our study concerning the success or failure of ablation. This might be due to the low number of cases or to the degree of junctional zone changes. In fact, the effect of transcervical endometrial resection might depend upon the degree of junctional zone changes, and patients with intrinsic adenomyosis were more likely to undergo re-intervention surgery than patients with either linear or serrated junctional zone [22]. However, hysteroscopic rollerball endometrial ablation as a surgical management in patients with adenomyosis associated with menorrhagia was found to be an effective and safe procedure which could reduce the need for the unnecessary major surgery of hysterectomy [23].

In a systemic review and meta-analysis [10], younger age, prior tubal ligation and preexisting dysmenorrhea were found to be associated with failure of endometrial ablation. Obesity and large submucous fibroids showed conflicting results and there was a need for further research to estimate the influence of these factors. This meta-analysis involved studies that were different from ours. The studies involved in this meta-analysis were using second generation endometrial ablation [10].

Our study did not show a statistically significant difference in ablation failure or success regarding preoperative menstrual irregularities and intermenstrual spotting. These findings were similar to a retrospective cohort study of a relatively large number of patients (968) [5].

As the first- and second- generation ablation techniques are effective and safe, we can expand our hysteroscopic endometrial ablation service to decrease the need for hysterectomy and particularly useful for patients with contraindications for medical therapy [24]. Both seem to be equally effective in reducing heavy bleeding and there was no evidence that rates of satisfaction differed significantly [25]. Despite second-generation techniques were often found to be easier to perform with shorter operative times with the ability to use local rather than general anesthesia and complications appeared to be less after second-generation techniques, the easiness of use can be a pitfall [25]. In fact, our experience with the first-generation technique showed that in expert hands and with strict adherence to energy settings and fluid management, significant complications could almost be eliminated.

Endometrial resection and ablation were effective alternative to hysterectomy for heavy menstrual bleeding and both were shown to have high satisfaction rates. Hysterectomy was associated with longer operating time, longer recovery period and higher rates of postoperative complications [26]. These features further support the incorporation of endometrial ablation service particularly in developing and under-resourced countries with limited financial, technical and medical capabilities to deal with complications.

In our practice, for endometrial ablation, we use the monopolar rollerball rather than the resectoscope. For bipolar resectoscope, in a randomized clinical trial, no significant difference was found in the postoperative PBAC score, amenorrhea rates, patient satisfaction, and need for re-intervention between ball endometrial ablation and trans-cervical resection of the endometrium using resectoscope [27]. This might have further explained the success and low complication rates in our study.

We did not assess post-ablation pain in our study as we followed patients for one year. It was reported in 20.8% of cases and the median number of days for the development of pain after ablation was 301 days [28].

The strengths of our study lied in the consistency of the study population and of the surgical technique. Moreover, the low cost of the procedure was a feature as no pre-operative thinning agents were used and, instead, whole endometrial cavity curettage was utilized to obtain tissue for assessment and to mechanically and instantly thin the endometrium to increase the effectiveness of the thermal damage on the endometrium.

Among pre-operative factors, adenomyosis, fluid deficit and combined adenomyosis and dysmenorrhea were found to predict failure of hysteroscopic endometrial ablation.

BMI, body mass index; EA, endometrial ablation; AUB, abnormal uterine bleeding; JUH, Jordan university hospital; g, gram; mL, milliliter; dL, deciliter; D&C, dilatation and curettage; IRB, institutional review board; U/S, ultrasound; mmHg, millimeter mercury; REA, rollerball endometrial ablation; ICD, international classification of diseases; CPT, current procedural terminology; COR, crude odds ratio; AOR, adjusted odds ratio; CI, confidence interval; mm, millimeter; min, minute; cc, cubic centimeter; MEA, microwave endometrial ablation; PBAC, pictorial blood assessment chart; LNG-IUS, levonorgestrel intra-uterine system; SM, submucosal.

All data are available from the corresponding author on reasonable request.

NA—design, concept and writing the manuscript; AA—statistical analysis and extraction of data; RN—statistical analysis and extraction of data; LA—statistical analysis and extraction of data; MA—statistical analysis and extraction of data; HA—drafting and revision. All authors read and approved the final manuscript.

The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Jordan University hospital decision number 58/2022, dated 17/02/2022.

Not applicable.

This research received no external funding.

The authors declare no conflict of interest.