Transcervical, intrauterine ultrasound-guided radiofrequency ablation of uterine fibroids with the VizAblate System: safety, tolerability, and ablation results in a closed abdomen setting

Transcervical radiofrequency ablation of fibroids that are 5 cm or larger in women with abnormal uterine bleeding

INTRODUCTION

Fibroids are the most common benign uterine tumors. Transcervical radiofrequency ablation with the Sonata® System offers a minimally invasive, incisionfree, organ-preserving therapy, with intraoperative visualization of fibroids using intrauterine ultrasound guidance. To demonstrate the effectiveness of transcervical radiofrequency ablation of fibroids that are 5 cm or larger using the Sonata® System, this retrospective analysis was collected.

METHOD

151 patients have been treated with this method in our department up to the time of this analysis. Only patients with at least one fibroid of ≥5 cm and with bleeding symptoms, who were treated with the Sonata® System were included in this retrospective study. A total of 50 patients were included in the study and 57 fibroids were treated.

RESULTS

A total of 57 fibroids were detected and treated, however FIGO 1 and 2 fibroids (in total three fibroids were excluded). The smallest fibroid was 4 cm and the largest fibroid was 12 cm. A single ablation was performed in 18 cases, two ablation steps in 16 cases, three ablation steps in 13 cases, and more than three ablation steps in three cases. Depending on ablation steps, the shortest ablation time was 3 min 15 s and the longest ablation time was 25 min 6 s, with an average time of 9 min 12 s. 86% of patients reported an improvement of symptoms Conclusion: Thus, the Sonata® System is a simple, minimally invasive, rapid and successful method that shows significant improvement of symptoms even in large myomas from ≥5 cm.

Temperature-dependent dielectric properties of human uterine fibroids over microwave frequencies

Microwave ablation is under investigation as a minimally-invasive treatment for uterine fibroids. Computational models play a vital role in the development, evaluation and characterization of candidate ablation devices. The temperature-dependent dielectric properties of fibroid tissue are essential for accurate computational modeling.Objective:To measure the broadband temperature-dependent dielectric properties of uterine fibroids excised during hysterectomy procedures.Methods: The open-ended coaxial probe method was employed for measuring the broadband dielectric properties of freshly excised human uterine fibroid samples (n = 6) obtained from an IRB-approved tissue bank. The dielectric properties (relative permittivity,ε_r, and effective electrical conductivity,σ_eff) were evaluated at temperatures ranging from 23 °C-150 °C, over the frequency range of 0.5-6 GHz. Linear piecewise parametrization with respect to temperature and quadratic parametrization with respect to frequency was applied to characterize broadband temperature-dependent dielectric properties of fibroid tissue.Results: The baseline room temperature values ofε_rvary from 57.5 ± 5.29 to 44.5 ± 5.77 units andσ_effchanges from 0.91 ± 0.19 to 6.02 ± 0.7 S m^-1over the frequency range of 0.5-6 GHz. At temperatures close to the water vaporization point,ε_r, drops considerably i.e. to 12%-14% of its baseline value for all measured frequencies.σ_effvalues initially rise till 98 °C and then fall to 11%-13% of their baseline values at 125 °C for frequencies ≤2.45 GHz. Theσ_efffollows a decreasing trend for frequencies >2.45 GHz and drops to ∼6 % of their baseline room temperature values.Conclusion:The temperature dependent dielectric properties of uterine fibroid tissues over microwave frequency range are reported for the first time in this study. Parametric models of uterine fibroid dielectric properties are also presented for incorporation within computational models of microwave ablation of fibroids.

Transcervical microwave ablation in type 2 uterine fibroids via a hysteroscopic approach: analysis of ablation profiles

Type 2 uterine fibroids are challenging to resect surgically as ≥ 50% volume of myoma lies within the myometrium. A hysteroscopic approach for ablating fibroids is minimally-invasive, but places a considerable burden on the operator to accurately place the ablation applicator within the target. We investigated the sensitivity of transcervical microwave ablation outcome with respect to position of the ablation applicator within 1 - 3 cm type 2 fibroids.Methods:A finite element computer model was developed to simulate 5.8 GHz microwave ablation of fibroids and validated with experiments inex vivotissue. The ablation outcome was evaluated with respect to applicator insertion angles (30°, 45°, 60°) , depth and offset from the fibroid center (±2 mm for 3 cm fibroid and ±1 mm for 1 cm fibroid) with 35 W and 15 W applied power for 3 cm and 1 cm fibroids, respectively. Power deposition was stopped when thermal dose of 40 cumulative equivalent minutes at 43 °C (CEM43) was accrued in adjacent myometrium.Results:Within the range of all evaluated insertion angles, depths and offsets, the ablation coverage was less sensitive to variation in angle as compared to depth and offset, and ranged from 34.9 - 83.6% for 3 cm fibroid in 140 - 400 s and 34.1 - 67.9% for 1 cm fibroid in 30 - 50 s of heating duration. Maximum achievable ablation coverage in both fibroid cases reach ∼ 90% if thermal dose is allowed to exceed 40 CEM43 in myometrium.Conclusion:The study demonstrates the technical feasibility of transcervical microwave ablation for fibroid treatment and the relationship between applicator position within the fibroid and fraction of fibroid that can be ablated while limiting thermal dose in adjacent myometrium.

A Systematic Review of the Treatment of Uterine Myomas Using Transcervical Ultrasound-Guided Radiofrequency Ablation with the Sonata System

OBJECTIVE

To evaluate the treatment success, possible side effects, and safety of radiofrequency ablation with the Sonata System.

DATA SOURCES

An electronic literature search in the PubMed and Medline databases was carried out from inception to August 2020.

METHODS OF STUDY SELECTION

The review was performed in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Keywords such as "Sonata," "transcervical ablation," and "uterine myoma" were used to identify all relevant articles independently by both authors. Full-text articles in English that reported at least 1 of the following outcomes were included in the study: reduction in perfused/total myoma volume, effect of treatment on bleeding intensity and myoma-related symptoms, number of surgical reinterventions, adverse events, return to activities of daily life, effects on surrounding tissue, and safety during pregnancy.

TABULATION, INTEGRATION, AND RESULTS

10 studies matching the inclusion criteria were identified and used for further analysis. A reduction in total and perfused myoma volume of 63.2% and 64.5% was achieved. One of the studies showed a 53.8 ± 50.5% (n = 48) reduction in Menstrual Pictogram Score, and another study showed a 51.1 ± 40.9% (n = 142) reduction in Pictorial Blood Loss Assessment Chart at 12 months. 87.2% (n = 190) of the patients reported a clinically meaningful reduction in menstrual blood loss after 12 months. While Symptom Severity Scores dropped by 28.8 ± 19.3, 23.3 ± 23.7, and 23.7 ± 19.4 points at 3, 6, and 12 months, respectively, Health-Related Quality of Life Scores increased to 77.5 ± 22.0, 82.8 ± 19.0, and 83.3 ± 20.5 points. One study had an 8% reintervention rate after 12 months, and another study showed a 0.7% and 5.2% rate after 12 and 24 months. After an average of 64 months after ablation, the reintervention rate was 11.8%. Time to return to activities of daily life was 2.9 ± 2.5 days. No related complications during pregnancy and delivery were reported.

CONCLUSION

Radiofrequency ablation with the Sonata System represents a minimally invasive, organ-preserving treatment option in patients with symptomatic uterine myomas, associated with clinically meaningful improvement of myoma-related symptoms.

Transcervical fibroid ablation with the Sonata™ system for treatment of submucous and large uterine fibroids

Objective

To examine the role and benefits of transcervical fibroid ablation (TFA) in the treatment of submucous and large uterine fibroids.

Methods

A subgroup of patients with submucous or large fibroids were analyzed from two prospective clinical trials (FAST‐EU and SONATA) of sonography‐guided TFA with the Sonata^® system. Key outcomes were changes in menstrual blood loss, symptom severity and health‐related quality of life on the Uterine Fibroid Symptom and Quality‐of‐Life Questionnaire, health‐related quality of life on the EQ‐5D questionnaire, and surgical reinterventions for heavy menstrual bleeding.

Results

Among 197 women (534 treated fibroids), 86% of women with only submucous fibroids and 81% of women with large fibroids (>5 cm) experienced bleeding reduction within 3 months post‐ablation. Overall symptom severity and health‐related quality of life showed sustained, significant improvements over 12 months. Additional fibroid mapping of large fibroids with magnetic resonance imaging in the FAST‐EU trial showed an average volume reduction of 68%. Among women with only submucous fibroids, the rate of surgical reintervention through 1 year of follow up was 3.7% in FAST‐EU and 0.0% in SONATA.

Conclusion

With the Sonata system, TFA is an effective single‐stage treatment option for non‐pedunculated submucous myomata, and larger or deeper uterine fibroids (including fibroid clusters) for which hysteroscopic treatment is not suitable.

ClinicalTrials.gov: FAST‐EU, NCT01226290; SONATA, NCT02228174.

Transcervical fibroid ablation with the Sonata™ system is an effective single‐stage treatment option for non‐pedunculated submucous and large myomata.

Assessment of thermal damage to myometrium during microwave ablation of uterine fibroids

Thermal ablation techniques are increasingly used for the treatment of symptomatic uterine fibroids. Thermal protection of myometrial tissue adjacent to the fibroid from ablation is critical to maximally preserve the uterus. This study presents a bench top experimental setup, using ex vivo bovine muscle as a surrogate tissue, for evaluating collateral thermal damage in tissues during fibroid ablation. The study reports on the effect of applicator insertion angles (67.5° and 90°) into a mock fibroid on the efficacy of treatment. 6 experiments were performed (3 for each insertion angle) with 30 W applied power at 2.45 GHz. The heating duration was restricted to the time at which a thermal dose of 10 cumulative equivalent minutes at 43 °C (10 CEM 43) was accrued at the boundary of the mock fibroid. Results showed that the volume of ablation inside the mock fibroid dropped considerably from 66% to 17% when the applicator insertion angle was changed from 90º to 67.5º, suggesting that insertion angle plays an important role during microwave ablation of fibroid. The proposed setup provides a method for validating computational models for accurate and safe delivery of ablation to target tissues in fibroid treatment.

Non-extirpative Treatments for Uterine Myomas: Measuring Success

OBJECTIVE

To analyze outcomes of nonextirpative treatments for uterine myomas compared with myomectomy.

DATA SOURCES

A systematic search of the following databases from inception to January 2020 was performed: Ovid Medline, Embase, PubMed, and Cochrane Controlled Register of Trials.

METHODS OF STUDY SELECTION

Two authors reviewed titles and abstracts for relevance, and full articles were obtained and evaluated for inclusion. Studies were included if they compared nonextirpative interventions for uterine myomas to myomectomy and reported at least one outcome of interest.

TABULATION, INTEGRATION, AND RESULTS

Of the 2010 articles identified and reviewed, 125 full text articles were reviewed, and 22 were ultimately included in the analysis. Nonextirpative treatments reviewed included uterine artery embolization (UAE; 16 studies, n = 9555 subjects), focused ultrasound (FUS; 4 studies, n = 1516), laparoscopic radiofrequency ablation (RFA; 3 studies, n = 49). UAE, FUS, and laparoscopic RFA groups were compared with patients undergoing myomectomy (n = 34 872, n = 20 677, n = 47 respectively). In comparison with myomectomy, UAE had similar quality of life scores, symptom severity scores, sexual function scores, ovarian function, and miscarriage rates following intervention. There was lower likelihood of conceiving after UAE and a higher rate of reintervention after UAE compared with myomectomy. FUS had similar postprocedure sexual function scores and reintervention rates compared with myomectomy. Laparoscopic RFA had similar quality of life scores, symptom severity scores, sexual function scores, reintervention rates, and pregnancy rates after the procedure compared with myomectomy.

CONCLUSION

Nonextirpative treatments for uterine myomas have similar outcomes to myomectomy in multiple domains, with most available evidence comparing UAE with myomectomy.

The CHOICES Study: Facility Level Comparative Cost, Resource Utilization, and Outcomes Analysis of Myomectomy Compared to Transcervical Fibroid Ablation

Purpose

The CHOICES study compared short-term resource utilization, facility costs, and perioperative patient outcomes between transcervical fibroid ablation (TFA) with the Sonata® system and myomectomy through a case-matched comparative trial design. This is the first facility-level comparative study conducted for TFA.

Patients and Methods

The study enrolled 88 patients from 4 centers equally divided among the two cohorts. The TFA arm consisted of 44 women who had enrolled in the SONATA Pivotal IDE trial, whereas the myomectomy arm included 44 patients who were identified through retrospective case-matching to the enrolled SONATA patients at the same 4 centers.

Results

TFA had a significantly lower mean operating room duration (90 minutes) and length of stay (5.2 hours) than myomectomy (143 minutes and 45.8 hours, respectively). The average total mean facility costs for TFA procedure ($7,563) were significantly lower than those associated with myomectomy ($11,425; p=0.002). TFA mean facility costs were also compared with other stratifications of myomectomy (inpatient or outpatient and surgical route). TFA facility costs were significantly lower than that associated with inpatient, abdominal, or laparoscopic myomectomy (all p<0.001).

Conclusion

TFA using the Sonata system has a significantly shorter operating room time and length of stay than myomectomy for the treatment of symptomatic uterine fibroids. All procedure, anesthesia, laboratory, pathology, and pharmacy costs were significantly higher for myomectomy as compared to TFA. TFA was also associated with significantly lower facility procedure-related costs compared to myomectomy, including inpatient, abdominal, or laparoscopic myomectomy.

The INTEGRITY Trial: Preservation of Uterine-Wall Integrity 12 Months After Transcervical Fibroid Ablation with the Sonata System

Objective: The aim of this research was to evaluate uterine-wall integrity 12 months after transcervical fibroid ablation (TFA) of uterine fibroids with the Sonata^® system (Gynesonics Inc., Redwood City, CA).

Materials and Methods: INTEGRITY is a secondary analysis of the FAST-EU clinical trial, a prospective, longitudinal, multicenter single-armed trial involving women with heavy menstrual bleeding secondary to fibroids who were treated at 7 academic and community hospitals in the United Kingdom, the Netherlands, and Mexico with transcervical, intrauterine, ultrasound-guided radiofrequency ablation (the Sonata system). TFA was performed on up to 5 fibroids per subject ranging from 1–5 cm in diameter as determined by magnetic resonance imaging (MRI). All measurements and comparisons, including uterine-wall thicknesses were derived from baseline and 12-month MRI scans by an independent core MRI center. Scans were analyzed to assess preservation of uterine-wall integrity and reviewed for uterine-wall anomalies after TFA with the Sonata system.

Results: Twenty-nine patients had baseline and 12-month MRI with contrast enhancement. Minimum uterine-wall thicknesses in all visible slices were >2.5 mm in diameter. No areas on MRI indicated any loss of uterine-wall integrity, compared with baseline imaging; comparison of baseline and postablation uterine-wall thicknesses revealed no significant changes.

Conclusion: Transcervical fibroid ablation with the Sonata system was associated with preservation of uterine-wall integrity in this patient cohort.

A New Paradigm for Uterine Fibroid Treatment: Transcervical, Intrauterine Sonography-Guided Radiofrequency Ablation of Uterine Fibroids with the Sonata System

Purpose of Review

This article provides the current evidence related to transcervical radiofrequency ablation of uterine fibroids under integrated intrauterine sonography guidance (the Sonata System).

Recent Findings

Published data on the treatment of fibroids with the Sonata System has demonstrated significant median reductions in total (73.3%) and perfused (73.3%) uterine fibroid volume, menstrual bleeding (72.3%), symptom severity (62.5%), and improvements in health-related quality of life (127%) at 12 months post-ablation. A clinical trial under an FDA Investigational Device Exemption is in progress.

Summary

The Sonata System is a promising treatment modality for uterine fibroids. As an incisionless, minimally invasive treatment that does not require general anesthesia or hospitalization, it has the potential for redefining the current paradigm for management of symptomatic fibroids.

Radiofrequency Ablation of Uterine Fibroids: a Review

Laparoscopic, ultrasound-guided radiofrequency ablation (RFA) is a new, FDA-cleared uterine sparing, outpatient procedure for uterine fibroids. The procedure utilizes recent technological advancements in instrumentation and imaging, allowing surgeons to treat numerous fibroids of varying size and location in a minimally invasive fashion. Early and mid-term data from multi-center clinical trials have demonstrated safety and efficacy, with resolution or improvement of symptoms and significant volume reduction. Re-intervention rates for fibroid symptoms have been low. The procedure is well tolerated with a typically uneventful and rapid recovery requiring NSAIDs only for postoperative pain. While post RFA pregnancy data are limited, the results are promising.

Uterine myomata: Organ-preserving surgery

Most women with uterine myoma are asymptomatic and do not require any treatment. However, myoma can also lead to menorrhagia, pressure symptoms, abdominal pain, and infertility. Management of symptomatic women with myoma depends on several factors, including age, desire for fertility, and myoma characteristics. Uterine myoma that distorts the uterine cavity, either submucous myoma or intramural myoma, with a submucous component reduces fertility, and is associated with increased uterine bleeding. The treatment of choice is hysteroscopic myomectomy or abdominal myomectomy, preferably by laparoscopy. Robotic assistance in laparoscopic myomectomy leads to outcomes similar to conventional laparoscopic myomectomy. However, it is expensive. Newer techniques include either laparoscopic or transcervical radiofrequency thermal ablation.

The FAST-EU trial: 12-month clinical outcomes of women after intrauterine sonography-guided transcervical radiofrequency ablation of uterine fibroids

The FAST-EU Trial was designed to establish the effectiveness and confirm the safety of transcervical intrauterine sonography-guided radiofrequency ablation with the VizAblate™ System in the treatment of symptomatic uterine fibroids. This was a multicenter, prospective, single-arm trial involving academic and community hospitals in the United Kingdom, the Netherlands, and Mexico. Women with qualifying uterine fibroids and heavy menstrual bleeding underwent intrauterine sonography-guided transcervical radiofrequency ablation (RFA) with the VizAblate System; anesthesia was individualized. Patients were required to have up to five fibroids from 1 to 5 cm in diameter. The primary trial endpoint was the percentage change in perfused fibroid volume, as assessed by contrast-enhanced MRI at 3 months by an independent core laboratory. Secondary endpoints, evaluated at 6 and 12 months, included safety, percentage reductions in the Menstrual Pictogram (MP) score, and the Symptom Severity Score (SSS) subscale of the Uterine Fibroid Symptom-Quality of Life (UFS-QOL) questionnaire, along with the rate of surgical reintervention for abnormal uterine bleeding and the mean number of days to return to normal activity. Additional assessments included the Health-Related Quality of Life (HRQOL) subscale of the UFS-QOL, nonsurgical reintervention for abnormal uterine bleeding, anesthesia regimen, patient satisfaction, and pain during the recovery period. An additional MRI study was performed at 12 months on a subgroup of patients. Fifty patients (89 fibroids) underwent transcervical radiofrequency ablation with the VizAblate System. At 3 and 12 months, perfused fibroid volumes were reduced from baseline by an average of 68.1 ± 28.6 and 67.4 ± 31.9 %, respectively, while total fibroid volumes were reduced from baseline by an average of 54.7 ± 37.4 and 66.6 ± 32.1 %, respectively (all P < .001 compared with baseline; Wilcoxon signed-rank test). At 12 months, mean MP score and SSS decreased by 53.8 ± 50.5 and 55.1 ± 41.0 %, respectively; the mean HRQOL score increased by 277 ± 483 %. There were four surgical reinterventions (8 %) within 12 months. This is the first report of the 12-month follow-up for patients in the FAST-EU Trial. In concert with previously reported 3- and 6-month endpoint data, the 12-month results of the FAST-EU Trial suggest that in addition to substantially reducing the perfused and total volume of targeted uterine fibroids, the VizAblate System is safe and effective through 12 months in providing relief of abnormal uterine bleeding associated with submucous, intramural, and transmural fibroids.

Transcervical, intrauterine ultrasound-guided radiofrequency ablation of uterine fibroids with the VizAblate® System: three- and six-month endpoint results from the FAST-EU study

This was a prospective, longitudinal, multicenter, single-arm controlled trial, using independent core laboratory validation of MRI results, to establish the effectiveness and confirm the safety of the VizAblate® System in the treatment of symptomatic uterine fibroids. The VizAblate System is a transcervical device that ablates fibroids with radiofrequency energy, guided by a built-in intrauterine ultrasound probe. Fifty consecutive women with symptomatic uterine fibroids received treatment with the VizAblate System. Patients had a minimum Menstrual Pictogram score of 120, no desire for fertility, and met additional inclusion and exclusion criteria. The VizAblate System was inserted transcervically and individual fibroids were ablated with radiofrequency energy. An integrated intrauterine ultrasound probe was used for fibroid imaging and targeting. Anesthesia was at the discretion of each investigator. The primary study endpoint was the percentage change in perfused fibroid volume, as assessed by contrast-enhanced MRI at 3 months. Secondary endpoints, reached at 6 months, included safety, percentage reductions in the Menstrual Pictogram (MP) score and the Symptom Severity Score (SSS) subscale of the Uterine Fibroid Symptom-Quality of Life questionnaire (UFS-QOL), along with the rate of surgical reintervention for abnormal uterine bleeding and the mean number of days to return to normal activity. Additional assessments included the Health-Related Quality of Life (HRQOL) subscale of the UFS-QOL, medical reintervention for abnormal uterine bleeding, and procedure times. Fifty patients were treated, representing 92 fibroids. Perfused fibroid volumes were reduced at 3 months by an average of 68.8 ± 27.8 % (P < 0.0001; Wilcoxon signed-rank test). At 6 months, mean MP and SSS scores decreased by 60.8 ± 38.2 and 59.7 ± 30.4 %, respectively; the mean HRQOL score increased by 263 ± 468 %. There were two serious adverse events (overnight admissions for abdominal pain and bradycardia, respectively) and no surgical reinterventions. These 6-month results suggest that the VizAblate System is safe and effective in providing relief of abnormal uterine bleeding associated with fibroids, with appropriate safety and a low reintervention rate.