HYSTEROSCOPIC STERILIZATION

With over 50,000 completed hysteroscopic sterilization procedures worldwide, and 5 years of data, what do we know so far about this innovation? It is now almost 4 years since the FDA approved Essure (Conceptus; San Carlos, Calif), the first hysteroscopic sterilization method available for use in the United States. Two other systems are in the works: Adiana (Adiana; Redwood City, Calif) has completed its Phase III clinical trial and Ovion (American Medical Systems; Minnetonka, Minn) is just beginning its clinical trial this year.

Comparison of the devices

Essure is a disposable delivery system with polyethylene (PET) fibers wound in and around a stainless steel inner coil. An outer coil of nitinol, a superelastic titanium/nickel alloy, is deployed to anchor the device across the uterotubal junction. Wound down, the micro-insert is 0.8 mm in diameter. Once released, the coil expands to 1.5 to 2.0 mm to hold the inner coil and PET fibers in place at the uterine cornua.

Over a period of about 3 months, the PET fibers elicit tissue ingrowth and proximal tubal occlusion. Women must use additional contraception during this time. Documentation of occlusion by a hysterosalpingogram about 3 months after device placement is required before patients may rely on the device and stop birth control.

Adiana (not yet available in the United States) uses a combination of controlled epithelial destruction and insertion of a porous biomatrix to induce vascularized tissue ingrowth. A catheter placed through the operating channel of a small hysteroscope delivers low-power bipolar electrosurgical energy to the tubal orifice (average less than 1 watt to the endosalpinx). A pushrod then delivers a small porous matrix of material into the tubal lumen. Ingrowth of healthy, vascularized tissue occurs over approximately 3 months, to occlude the tubes.

Retention of the matrix and tubal occlusion are documented by both transvaginal ultrasonography and hysterosalpingogram before patients may discontinue additional contraception.

Accessing the tubes

One of the greatest hurdles for occluding the fallopian tubes hysteroscopically is access to the tubes. Both the Adiana clinical trial (not yet published) and the post-market analysis of Essure (not yet published) have demonstrated excellent bilateral placement rates.

Technique is not hard to learn. Both types of devices are inserted through the operating channel of a small hysteroscope. Initial concerns about the ability to access the tubal ostia do not appear to be an issue—at least for those early-adopter physicians performing the procedures. Both clinical trials included gynecologists who were not experienced in operative hysteroscopy. These studies found that cannulation of the tubes is a technique that is easy to learn and rapidly accomplished in most circumstances.

Bilateral placement rates were similar for both devices in the pivotal trials: Adiana 95% (612/655); Essure 90% (464/518).

What are the contraindications?

Approximately 10% of patients have factors that preclude bilateral device placement:

Anatomic factors

• Blocked or stenotic tubes
• Intrauterine adhesions
• Visual field obstructed by polyps, fibroids, or shaggy endometrium
• Lateral tubes

Device or procedure failures due to

• Tubal spasm
• Patient pain/intolerance
• Device malfunction

A second procedure (after correcting the initial problems) will be successful in many women who have what appears to be a technical glitch.

Clinical outcomes, so far

Ultimately, of course, the success of these procedures and the benefits to our patients will be determined by the placement rates in the real world and the ability of a majority of women to rely on the devices for permanent sterilization.

What can we say so far?

Bilateral placement rates

Although the bilateral placement rates for Essure in the pivotal trial were 88% with one attempt, increasing to 92% of all patients enrolled with a second attempt, the data from the postmarket study is even more promising. After FDA approval in November 2002, the manufacturer trained gynecologists in the procedure, and then monitored clinical outcomes in the initial cases performed by these surgeons once they had completed their training and mandatory proctored cases (data not yet published).

Physicians who participated in the clinical trial were excluded from this analysis. The bilateral device placement rate for these women treated by novice users is over 94%. Adiana’s Phase III trial data demonstrate a similar bilateral success rate. It appears that despite the misgivings of many ObGyns, these systems are easy to learn.