Endometrial resection and ablation are an intermediate treatment for heavy menstrual bleeding (HMB). Many women do not like the continuous use of hormones, nor do they prefer a rigorous treatment as hysterectomy. The first generation of endometrial resection/ablation is now superseded by the second-generation endometrial ablation.
Both seem to be equally effective in reducing HMB, and there was no evidence that rates of satisfaction differed significantly. Overall, second-generation techniques were often easier to perform with shorter surgery times and the ability to use local rather than general anaesthesia. Complications seem to be less after second-generation endometrial ablation; however, the easiness of use can be a pitfall.
Prognostic parameters should be taken into account while counselling women who opt for an endometrial ablation. The most important prognostic parameters are age (satisfaction increases with age) and preoperative dysmenorrhoea (decreases satisfaction).
Highlights
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Second-generation ablation should be favoured over first-generation endometrial ablation.
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Patient satisfaction is high after second-generation endometrial ablation.
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Younger age and preoperative dysmenorrhoea are the most important prognostic parameters for the failure of endometrial ablation.
Introduction
Since the 1980s in the past millennium, endometrial resection has been introduced as a treatment option for heavy menstrual bleeding (HMB) . HMB has a significant impact on the medical, social economic and psychological well-being of women . When medical treatment fails, surgical interventions can be considered. Hysterectomies are performed in 30–40% of the patients for the treatment of HMB . The level of satisfaction with hysterectomy is usually high, but patient preference studies show that women place a high value on retaining their uterus, and they have a strong preference for avoiding hysterectomy . Endometrial resection and endometrial ablation are an alternative to the hysterectomy, as these techniques are relatively minor surgical procedures, and they will preserve the uterus. It all started with the laser resection , the rollerball ablation and the transcervical endometrial resection (TCRE) . These techniques are commonly referred to as ‘first-generation ablation techniques’. The laser technique was expensive and difficult to learn; the other two techniques overtook laser as the main method of ablation. However, the transcervical endometrial resection (TCRE) is performed in a combination with the rollerball, whereas the rollerball alone will not be used so often anymore. Since the introduction of the TCRE in 1983, the technique of this procedure has not been changed so much, although a bipolar current resectoscope is now an alternative option for the monopolar current resectoscope . Meanwhile, a lot of disposable devices were introduced to perform an endometrial ablation, the so-called second-generation endometrial ablations or global endometrial ablations as they will be referred to in the American literature. In 1994, the first ‘global’ endometrial ablation, the Thermachoice™ (Ethicon Women’s Health and Urology, Somerville, NJ, USA) balloon, was introduced in the USA. Soon thereafter, another balloon, the Cavaterm (Veldana Medical SA, Morges, Switzerland) , and several other techniques were introduced, namely microwave (MEA™, Microsulis, Hampshire, UK) , circulating hot water (HTA™, Boston Scientific, Boston, MA, USA) , cryoablation (HerOption™, Cooper Surgical, Trumbull, CT, USA) and bipolar radiofrequency (Novasure™, Hologic, Bedford, MA, USA) . Today in daily practice, endometrial ablation is a common therapy to treat HMB. Several techniques are developed for ablating and destroying the endometrium to reduce HMB, but some have been abandoned already. It is not clear which approach offers the best option in terms of effectiveness and safety. The aim of this review is to give an update of the efficacy, safety and acceptability of the commonly used methods, both by comparing individual techniques and by making overall comparisons between first-generation and second-generation techniques, and to mark the differences between the individual techniques. Moreover, prognostic parameters for the treatment of HMB by endometrial ablation will be given.
Daily practice of endometrial ablation
There are several differences between the first-generation and the second-generation endometrial ablations. The first-generation techniques are all guided by hysteroscopy. Under direct vision, the total endometrium can be resected or ablated. Intrauterine abnormalities: as a very large uterine cavity, small myomas and polyps can be performed with a hysteroscopic-guided endometrial ablation technique. On the other hand, first-generation ablation techniques need the use of a distension fluid, which can lead to fluid overload and water intoxication . The first-generation techniques have a learning curve. In skilled hands, the results and complications will be low, but the efficacy depends on the quick resection of all the endometrial tissue, which can be a challenge. The change from unipolar to bipolar current meant a change in distension medium , from glycine or sorbitol for the unipolar resectoscope to sodium chloride (NaCl) for the bipolar resectoscope. NaCl does not give the risk of water intoxication, although the maximum fluid loss should still not exceed 2–2.5 l . Most of the resectoscopes have a diameter of 9 mm, which make their use as an office procedure rather unattractive. However, smaller resectoscopes are now on the market, and they can be promising for the future although limited research has been published . The resectoscope is a reusable instrument, which can reduce costs.
The second-generation devices are (except from the HTA) non-hysteroscopic, disposable procedures. The procedure time is mostly fixed, and its use does not need a learning process. Most of those can be performed as an office procedure; ablation time ranges from 1.5 to 10 min and the diameter differs from 4 to 7.5 mm, which means that the dilatation of the cervix can be minimised . Due to the costs of the disposable devices and the different reimbursement rules, these devices are still not unrolled in all countries.
In the Cochrane analysis, all the second-generation devices that have been sold on the market and were studied in a randomised controlled trial (RCT) were included . However, there are some devices that have been evaluated but were available only for a short time on the market. Endometrial laser intrauterine thermotherapy (ELITT) was associated with highly significant improvements in amenorrhoea rates compared with all other methods, although this was one small study, but this device is no longer marketed (C. Dunn, Karl Storz, personal communication) . The microwave endometrial ablation system from Microsulis (Portsmouth, Hampshire, UK) has been withdrawn from the European market after Hologic acquired the intellectual property for the device (Microsulis Medical, press release, 2011). This technique has been evaluated thoroughly, and it was used for years with good results . A new balloon device (Thermablate EAS, Los Angeles, CA, USA) is now on the market, but no RCT of this balloon device has been published until now . However, a trial comparing bipolar endometrial ablation versus balloon endometrial ablation (Thermablate EAS) in the outpatient setting has been registered (ISRCTN17974690 ).
Daily practice of endometrial ablation
There are several differences between the first-generation and the second-generation endometrial ablations. The first-generation techniques are all guided by hysteroscopy. Under direct vision, the total endometrium can be resected or ablated. Intrauterine abnormalities: as a very large uterine cavity, small myomas and polyps can be performed with a hysteroscopic-guided endometrial ablation technique. On the other hand, first-generation ablation techniques need the use of a distension fluid, which can lead to fluid overload and water intoxication . The first-generation techniques have a learning curve. In skilled hands, the results and complications will be low, but the efficacy depends on the quick resection of all the endometrial tissue, which can be a challenge. The change from unipolar to bipolar current meant a change in distension medium , from glycine or sorbitol for the unipolar resectoscope to sodium chloride (NaCl) for the bipolar resectoscope. NaCl does not give the risk of water intoxication, although the maximum fluid loss should still not exceed 2–2.5 l . Most of the resectoscopes have a diameter of 9 mm, which make their use as an office procedure rather unattractive. However, smaller resectoscopes are now on the market, and they can be promising for the future although limited research has been published . The resectoscope is a reusable instrument, which can reduce costs.
The second-generation devices are (except from the HTA) non-hysteroscopic, disposable procedures. The procedure time is mostly fixed, and its use does not need a learning process. Most of those can be performed as an office procedure; ablation time ranges from 1.5 to 10 min and the diameter differs from 4 to 7.5 mm, which means that the dilatation of the cervix can be minimised . Due to the costs of the disposable devices and the different reimbursement rules, these devices are still not unrolled in all countries.
In the Cochrane analysis, all the second-generation devices that have been sold on the market and were studied in a randomised controlled trial (RCT) were included . However, there are some devices that have been evaluated but were available only for a short time on the market. Endometrial laser intrauterine thermotherapy (ELITT) was associated with highly significant improvements in amenorrhoea rates compared with all other methods, although this was one small study, but this device is no longer marketed (C. Dunn, Karl Storz, personal communication) . The microwave endometrial ablation system from Microsulis (Portsmouth, Hampshire, UK) has been withdrawn from the European market after Hologic acquired the intellectual property for the device (Microsulis Medical, press release, 2011). This technique has been evaluated thoroughly, and it was used for years with good results . A new balloon device (Thermablate EAS, Los Angeles, CA, USA) is now on the market, but no RCT of this balloon device has been published until now . However, a trial comparing bipolar endometrial ablation versus balloon endometrial ablation (Thermablate EAS) in the outpatient setting has been registered (ISRCTN17974690 ).
Effectiveness of TCRE and second-generation endometrial ablation
All reviews of endometrial ablation will start by looking in the Cochrane database . The splendid research performed by this group will be the basis of this review as well. The latest update is from 2013; therefore, it is a recent and up-to-date review. The Birmingham research group started an individual patient database for studies performed in the field of HMB (integrated project delivery (IPD)-HMB) . This database includes RCTs concerning first-generation and second-generation endometrial ablations of which the raw data are available. Raw data were available from 2814 women randomised into 17 trials (seven trials including 1359 women for first-generation vs. second-generation endometrial destruction; six trials including 1042 women for hysterectomy vs. first-generation endometrial destruction; one trial including 236 women for hysterectomy vs. Mirena (Bayer HealthCare Pharmaceuticals Inc., NJ, USA); three trials including 177 women for second-generation endometrial destruction vs. Mirena) . The publications of this IPD-HMB group will also be used for this overview.
The Cochrane database of 2009 consisted of 21 RCTs of which four extra have been added to the review of 2013, which makes it 25 RCTs. These RCTs compare first with another first-generation technique, first-generation with second-generation endometrial ablation techniques or second-generation techniques with each other. The 25 included studies contained 4056 premenopausal participants, mostly within the age range 30–50 years.
First-generation endometrial ablation
Of the first-generation therapies, the laser is very expensive, and it needs a highly qualified surgeon . To date, the laser vaporisation is not anymore used for the endometrial ablation. In the performed trial comparing TCRE with the laser ablation, there was no evidence of significant differences between groups in the primary outcomes measured, that is, amenorrhoea rate, combined amenorrhoea and hypomenorrhoea rate, menstrual blood loss at 6 months or satisfaction at 12 months . Endometrial thinning with gonadotrophin-releasing hormone agonist (GnRHa) or danazol before hysteroscopic surgery improves operating conditions and short-term post-operative outcomes . GnRHa produced slightly more consistent endometrial thinning than was produced by danazol, although both achieved satisfactory results. The effect of these agents on longer-term post-operative outcomes was reduced with time.
The rollerball in comparison with the TCRE shows no evidence of significant differences in re-interventions after 2-year, 5-year and 10-year follow-up (FU), or in the complication rates measured (fluid deficit and perforation) .
In conclusion, not one of the three first-generation endometrial ablations has a real advantage over the others. Although there does not seem to be a real advantage of the TCRE, to date this is the technique mostly used for the first-generation techniques.
First-generation endometrial ablation versus second-generation endometrial ablation
The rollerball ablation was studied versus cryoablation and balloon ablation, but there was no evidence that the rollerball had better results on all parameters . Patients appeared to be more satisfied with microwave than TCRE at 2 and 5 years after surgery . At 10 years of FU, this difference has been reduced .
With regard to secondary outcomes, the duration of surgery was consistently shorter with second-generation ablation, and local anaesthesia was more likely to be given.
In the IPD-HMB database, a comparison of the first-generation versus the second-generation endometrial ablation techniques showed no significant difference in effectiveness defined as satisfaction .
In conclusion, there is no evidence that the first-generation or the second-generation endometrial ablation is superior. However, a lot of practical considerations favour the choice of second-generation techniques.
Second-generation endometrial ablation techniques
Rates of dissatisfaction and heavy bleeding are consistently low for second-generation techniques, which, as a group, represent an excellent conservative alternative to hysterectomy. Bipolar radiofrequency and microwave ablation technique are associated with higher amenorrhoea rates than other methods . Bipolar radiofrequency ablation (Novasure™, Hologic, Bedford, MA, USA) was associated with significantly more amenorrhoea than balloon ablation, but this was not confirmed by a comparison of pictorial blood assessment chart (PBAC) scores or of the extent to which women were satisfied with their surgery . Surgery was shorter with bipolar ablation, and pelvic masses scores (PMSs) reduced. There was no evidence that bipolar radiofrequency ablation resulted in less reoperation due to dissatisfaction with surgery. Long FU showed a reduction in the difference of patient satisfaction between the bipolar ablation and the balloon ablation . Bipolar ablation also increased amenorrhoea and satisfaction rates when compared with hydrothermal ablation . The procedure time was shorter with bipolar ablation, and women were less likely to require additional surgery at a later FU. Amenorrhoea rates appeared to be increased with microwave when compared with balloon, but no differences were found in PBAC scores or satisfaction . Also, the Cavaterm balloon was compared with the bipolar endometrial ablation, and it showed higher amenorrhoea for the bipolar endometrium ablation, but no difference in patient satisfaction . A retrospective population-based trial showed that one in six women has further surgery after endometrial ablation for HMB, which is a higher rate than reported in clinical trials . This risk of further surgery decreases with age . In daily practice without inclusion criteria for a trial, results will be always less in comparison with these trials. On the other hand, about 80% of the women will not be treated after the endometrial ablation, and they will not be saved a hysterectomy.
In order to compare the different second-generation techniques with each other and to aim to make a ranking, Daniels et al. published a network meta-analysis . Of the three most commonly used techniques, this network meta-analysis showed that bipolar radiofrequency and microwave ablation resulted in higher rates of amenorrhoea than thermal balloon ablation at around 12 months (odds ratio (OR): 2.51, 95% confidence interval: 1.53–4.12; P < 0.001; and 1.66, 1.01–2.71, P = 0.05, respectively), but there was no evidence of a convincing difference between the three techniques in the number of women dissatisfied with treatment or still experiencing heavy bleeding. Compared with bipolar radiofrequency and microwave devices, an increased number of women still experienced heavy bleeding after free-fluid ablation (2.19, 1.07–4.50, P = 0.03; and 2.91, 1.23–6.88, P = 0.02, respectively). Compared with radiofrequency ablation, free-fluid ablation was associated with reduced rates of amenorrhoea (0.36, 0.19–0.67, P = 0.004) and increased rates of dissatisfaction (4.79, 1.07–21.5, P = 0.04) .
Data from the UK hospital episode statistics show a significant increase in the overall number of inpatient endometrial ablative techniques, though radiofrequency ablation techniques are recently the most rapidly rising techniques used . These data do not include ambulatory procedures, which are also increasing rapidly but are not adequately coded in the hospital episode data. Unfortunately, the first-generation techniques were not included as well, but consensus is that such techniques have rapidly been superseded.
Overall comparison of first-generation with second-generation techniques
Regarding the overall comparison of second-generation with first-generation techniques, there is no evidence that either broad category is more effective than the other in reducing HMB, and there was no evidence that rates of satisfaction differed significantly. Overall, second-generation techniques were at least as effective as first-generation methods, but they were often easier to perform with shorter surgery times and the ability to use local rather than general anaesthesia . Some types of intra-operative and post-operative complications, such as fluid overload, perforation, cervical lacerations and haematometra, were more common with first-generation ablation; and other types of complications, nausea, vomiting, uterine cramping and pain, were more common with second-generation techniques . Concerns about these ‘blind’ methods leading to bowel injuries from undetected uterine perforations did not seem to be confirmed in the published studies. However, there are many examples such as in the Manufacturer and User Facility Device Experience (MAUDE) database that such events can occur, and great care must be taken to minimise the risk of such potentially serious complications. There was no evidence that rates of re-intervention, either repeat ablation or hysterectomy or both, differed between first-generation and second-generation ablations. A recurrent comment about the newer techniques that rely on ‘devices’ inserted into the uterine cavity to destroy the endometrium was the incidence of equipment failure. However, the newer techniques are potentially quite complex, and the potential remains for mechanical breakdown to occur. In addition, considerable experience in intrauterine cavity assessment and manipulation is required to safely use any of these devices . There are potential disadvantages to stressing how little operator skill is required for a device, which has the capacity to cause extensive intra-abdominal trauma. Of the newer techniques, only some have a safety check (Novasure, Hologic, Boston, MA, USA), which can prevent serious harm. However, it is possible to overrule this safety check, and bowel burn has been documented as a complication of the bipolar endometrial ablation . New devices should be invented with one or another safety check to prevent activation of the device after an unmeant perforation of the uterus wall. A safety check is required to diminish severe complications as bowel injury.
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