4 global ablation devices: Efficacy, indications, and technique
Newer endometrial ablation technologies are easy to learn, and high efficacy rates match earlier techniques.
Modifications of this technique included a loop electrode that used monopolar electrical energy to “shave” the thicker portions of endometrium. In some reports, the rollerball electrode was used to reach the uterine cornu and endocoagulate the lower uterine segments. The most successful reports of this approach used a loop electrode to shave the endometrium followed by rollerball coagulation of the shaved areas. Amenorrhea rates with these techniques approached 60%.
Thermal balloon ablation
ThermaChoice (Gynecare, Somerville, NJ), the first global-ablation device to be marketed, was FDA-approved in 1997.6,7 It is a single-use balloon that is filled with fluid (5% dextrose and water) and inflated to a pressure of 180 mm Hg.
Technique. After general or regional anesthesia and prior to balloon insertion, remove the superficial endometrium by suction curettage.
The balloon contains a central heating element that warms the fluid to 87°C for 8 minutes via electronic control. Pressure within the balloon must be stabilized within the uterine cavity.
Safety features include a pressure shut-off device that activates at 210 mm Hg or higher and 45 mm Hg or below. The procedure is terminated if the temperature exceeds 95°C or falls below 75°C.
Caveats. The device may not function optimally if the cavity is irregular. In addition, it may not destroy residual and endometrial tissue in cornual regions of the uterus.
Postoperative response. Patients have reported increased uterine pain secondary to release of prostaglandins and other tissue factors that may increase uterine contractility.
What the data show. In a series of 296 patients followed for 1 year, 88% reported decreased flow and 14% achieved amenorrhea.6 Meyer et al7 compared thermal balloon ablation with the rollerball technique and found an amenorrhea rate of 27% with rollerball and 15% with the balloon. Patient satisfaction remained high in both groups: 87% for rollerball versus 86% with the balloon.
More recently, 5- and 7-year follow-up studies have been published. At 5-year follow-up, Loffer and Grainger8 concluded that thermal balloon ablation therapy was an effective treatment of menorrhagia in premenopausal women, with clinical outcomes similar to rollerball ablation. Patient satisfaction was noted in 93% of women treated with thermal balloon ablation and 100% of those treated with rollerball ablation. A 7-year multicenter follow-up study of thermal balloon therapy defined avoidance of hysterectomy as the primary outcome.9 Overall, the probability of avoiding any surgery was 75% at 6.5 or 7 years.
Thermal fluid ablation
The HydroThermAblator (Boston Scientific, Natick, Mass) is similar to the balloon. It delivers heated saline at 90°C directly to the uterine cavity under hysteroscopic guidance.10 This solution is circulated at gravity pressure so that it remains in the uterine cavity and does not flow out the fallopian tubes into the peritoneal cavity. Approximately 10 minutes is required for the procedure.
Preparation is via GnRH-agonist hormonal suppression or a suction D&C.
Technique. Following regional or general anesthesia, the uterus is sounded and the endocervical canal dilated sufficiently to insert the operative hysteroscope. After inspection of the uterine cavity by direct visualization via the hysteroscope/TV monitor, the tubing that delivers the heated saline is connected to the operative hysteroscope to perform the ablation. The procedure takes place under direct visualization.
Safety features include automatic shutdown if there is a 10-mL fluid loss or an increase in fluid accumulation in excess of 20 mL.
What the data show. At 12 months, 1 trial reported an amenorrhea rate of 50%, hypomenorrhea of 39%, and eumenorrhea of 5.5%.11
Cryotherapy
The Her Option cryoablation system (American Medical Systems, Minnetonka, Minn) involves insertion of a cryoprobe into the uterine cavity, cooling it to –100 to –120°C to form an ice ball, and destroying adjacent endometrium.
Preparation is via preoperative hormonal suppression with a GnRH agonist.
Abdominal ultrasound monitoring is necessary for insertion of the cryoprobe and ice ball formation.
Technique. In some patients, multiple ice balls may be needed to thoroughly ablate the endometrial cavity, which can prolong the procedure.
What the data show. A multicenter randomized trial comparing durability of treatment effects after endometrial cryoablation versus rollerball electroablation for abnormal uterine bleeding found 94% of patients (n = 94) free of abnormal uterine bleeding at 24 months of follow-up, compared to 93% of rollerball electroablation patients (n = 43).12
Impedance-controlled endometrial ablation
The NovaSure device (Novacept, Palo Alto, Calif) consists of a hand-held, disposable, 3-dimensional ablation wand that functions as a bipolar electrode. It is constructed of gold-plated fabric mesh mounted on a metal wire frame.
Treatment time. The procedure can be completed in less than 120 seconds. Because it is so quick, this technique can be accomplished with paracervical blockade and conscious sedation in suitable patients.
