Biomaterials in Obstetrics and Gynecology - Biomaterials Science: An Integrated Clinical and Engineering Approach - page 153

Finally, spermicides are much more effective when used along with
mechanical barriers, such as a condom or a diaphragm [5].
Permanent Tubal Sterilization
Essure ® , Conceptus Inc.
After completion of the family, many women seek a permanent measure of
contraception. Until recently, the most popular permanent contraception
was tubal ligation. This operative procedure, usually done laparoscopically,
requires general anesthesia and short hospital stay. New emerging technol-
ogy, first approved by the FDA in 2002, has revolutionized permanent ster-
ilization. Essure ® is a trans-cervical contraceptive device that offers women
seeking permanent contraception in a non-surgical non-hormonal solution.
In this office procedure, flexible inserts are inserted into the fallopian tube
through the cervix and the uterus via hysteroscopy. The inserts are made of
inner polyethylene terephthalate (PET) fibers to induce tissue fibrotic reac-
tion and are held in place by a flexible stainless steel inner coil and a dynamic
outer nickel titanium alloy coil. PET fibers are being used because of their
ability to induce tissue ingrowth into medical devices in other procedures,
such as arterial grafts. The physician performing the hysteroscopy identifies
the fallopian tube ostia and inserts these coils. During the next three months,
there is an inflammatory response caused by the invasion of macrophages,
fibroblasts, giant cells, and plasma cells, resulting in fibrosis in the fallopian
tube around the insert. This natural “plug” prevents sperm from reaching
the eggs. After three months, a hystero-salpingogram is performed by inject-
ing dye through the cervix to ensure a complete blockade of both fallopian
tubes. A follow-up study of 5 years reported excellent results with zero preg-
nancies and a 99.74% success rate. Failures in this study were to the result of
the inability to insert or of the expulsion of the device. The risks include pain
and cramping, uterine perforation, inability to insert, allergic reaction to the
materials, and vasovagal response (fainting) during insertion. In the first 3
months there is risk of failure as well as ectopic pregnancy, and therefore a
complementary contraceptive method is recommended [6].
Adiana ® Hologic, Inc.
This permanent sterilization method is a combination of controlled thermal
damage to the lining of the fallopian tube followed by insertion of a non-
absorbable biocompatible silicone elastomer matrix into the tubal lumen.
This procedure is done under hysteroscopic guidance as well. A catheter is
inserted into the tubal ostium and delivers radiofrequency (RF) energy for 1
minute, causing a lesion in the fallopian tube lumen. Then, a 3.5-mm silicone
matrix is placed in the injured area. During the next few weeks, tubal occlu-
sion is achieved by fibroblast ingrowth into the matrix, which serves as per-
manent scaffolding and allows for space-filling. As with the Essure ® device,