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4 global ablation devices: Efficacy, indications, and technique

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Newer endometrial ablation technologies are easy to learn, and high efficacy rates match earlier techniques.


 

References

KEY POINTS
  • These techniques are easy to learn and use, and offer results comparable to rollerball procedures. Selected patients can be treated successfully in the office setting.
  • It is is vital that the patient have a reliable and permanent form of contraception, such as tubal ligation or vasectomy.
  • Long-term complications, though rare, include endometrial hyperplasia and occult endometrial carcinoma.
Endometrial tissues have amazing regenerative properties, with a controlled growth rate exceeding that of all known tumors. Within days of onset of menses, under appropriate estrogen stimulation, the endometrial surface “repairs” and “rebuilds”—from the basalis layer on up—rapidly achieving a thickness of 8 to 10 mm.

Thus, attempts to destroy it and achieve amenorrhea have met with limited success.

Hysterectomy is still the definitive treatment for excessive uterine bleeding, but a more conservative treatment, ablation, uses surgical or chemical means to obliterate the endometrial surface. Newer devices (FDA approved since 1997) allow office-based or same-day surgery; recovery time is shorter, and complication rates are lower than for hysterectomy.

This approach has gained popularity as instrumentation has improved; yet, because the endometrial surface is so resilient, success rates fall well shy of 100%. This article summaries the data on efficacy, and describes the indications, preoperative evaluation, and technique for 4 ablation options:

  • thermal balloon ablation
  • thermal fluid ablation
  • cryotherapy
  • impedance-controlled ablation

Other modalities include microwave, laser, and a progestin-releasing intrauterine contraception system.

Each uses a different energy-transfer technique to destroy the endometrium ( TABLE).

TABLE

4 global ablation devices at a glance

THERMAL BALLOON (THERMACHOICE)THERMAL FLUID (HYDROTHERMABLATOR)CRYOTHERAPY (HER OPTION)IMPEDANCE-CONTROLLED (NOVASURE)
PretreatmentYesYesYesNo
Time of energy delivery8 minutes10 minutes10–12 minutes90–120 seconds
Cornual ablationNoYesUser-dependentYes
PrincipleBalloon filled with fluid (5% dextrose in water) at 87°CHydrothermal circulation of saline at 90°CProbe with transfer media creates ice ball at –100 to –120°CBipolar, radiofrequency ablation at 100°C
Direct visualizationNoneHysteroscopyUltrasound guidanceNone
Safety featuresPressure and temperature-sensing cutoffsFluid loss detection systemUltrasound guidanceUterine cavity integrity assessment system

Indications

The typical candidate for endometrial ablation has heavy menses requiring excessive sanitary protection (eg, tampon and pad simultaneously); her daily activity frequently is limited. The patient may have tried such management as nonsteroidal anti-inflammatory agents, oral contraceptives, or surgical dilatation and curettage (D&C) without success.

Excessive or abnormal uterine bleeding is defined as blood loss exceeding 80 mL per menses or a menstrual flow longer than 7 days. Abnormal uterine bleeding affects 22% of women of reproductive age.1 Each year in the United States, approximately 180,000 women undergo hysterectomy for this indication.2

The optimal patient for endometrial ablation has a history of regular menses without excessive dysmenorrhea, which could suggest an underlying diagnosis of adenomyosis. (Findings suggestive of this difficult-to-diagnose condition include a tender, soft, boggy uterus at the time of menses.) Many women with adenomyosis fail to achieve adequate pain relief with endometrial ablation alone and eventually require a hysterectomy.

The patient should have completed childbearing and have a permanent method of contraception in place—endometrial ablation only reduces fertility, it does not eliminate it.

Preoperative evaluation

Laboratory studies include a complete blood count and urine human chorionic gonadotropin level, as well as screening for bleeding disorders when indicated.

A bleeding diary helps quantify symptoms. Its use should be encouraged.

Other tests and examinations. Also recommended are endometrial biopsy, a Pap test, and assessment of the endometrial cavity via hysteroscopy or sonohysterography.

Biopsy should reflect histologically normal tissue. The patient should have:

  • regular menstrual cycles lasting 25 to 34 days
  • no uterine anomaly or potential myometrial wall defect from a previous classical cesarean or transmural myomectomy
Preparing the endometrium. After careful patient selection and appropriate counseling for the procedure, preoperative preparation of the endometrium may be required, depending on the technique chosen. For example, thermal fluid ablation requires pretreatment with a gonadotropin-releasing hormone (GnRH) agonist or suction curettage. The most widely used preparation methods are hormonal treatment with GnRH agonists over 2 menstrual cycles, and suction D&C.

Contraindications

Anovulatory patients may not be good candidates because islands of endometrial tissue can remain after ablation. These tissue “nests” may spontaneously change to hyperplasia or endometrial carcinoma (due to unopposed estrogen). Further, uterine bleeding may not always occur when hyperplasia is present after endometrial ablation, delaying this serious diagnosis.

Relative contraindications include intramural or submucosal uterine myomas.

Earlier techniques: Hysteroscopic ablation

Techniques developed earlier require expert operative hysteroscopic skills and should be performed by experienced gynecologic surgeons to minimize complications.

For example, the first treatment of menorrhagia using a hysteroscopic approach with a Nd:YAG laser power source, reported in 1981 by Goldrath et al,3 utilized 55 watts of power with a 600-micron fiber dragged across the endometrium. Later, other surgeons used a rollerball unipolar electrode that coagulated the surface with continuous contact.4,5

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