WASHINGTON (AP) -- A tiny, spring-like device threaded into the fallopian tubes seems to offer women permanent birth control without surgery and should be approved for sale, advisers to the Food and Drug Administration voted Monday.

If the FDA agrees, the Essure device could become an easier method of sterilization, the most widely used form of contraception. The FDA isn't bound by its advisers' recommendations, but typically follows them.

The advisers did attach some conditions. Noting Essure can't always be inserted successfully, the panel urged FDA to require better data on the failure rate for potential patients to consider.

The panel also wants Essure maker Conceptus Inc. to continue studying women who tested the experimental device for a full five years, to ensure its effectiveness. The advisers also urged some additional steps to assure doctors are properly trained to insert the device and that women understand it's not reversible birth control, said FDA engineer Colin Pollard, chief of gynecologist devices.

With standard sterilization, doctors cut and tie the fallopian tubes, or cauterize or clip them shut, to keep eggs released by the ovaries from reaching the uterus. It requires either conventional or minimally invasive surgery.

The operation is very safe but any surgery carries some risks, so gynecologists have long sought a nonsurgical option.

With Essure, doctors thread a wire up the vagina, into the uterus and up each fallopian tubes to place the tiny spring. Flexible coils temporarily anchor it inside the fallopian tubes. Dacron-like mesh embedded in the coils irritates the tube's lining and, over three months, scar tissue grows to permanently plug the tube.

It doesn't offer immediate birth control, and women must be tested to ensure the scar tissue has fully blocked both tubes.

All women can't be successfully implanted; one study found about a 12 percent failure rate on the first try, Pollard said.

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