April 11, 2006

The FDA recently granted a humanitarian device exemption (HDE) to fetoscopy instrument sets distributed by Karl Storz Endoscopy America in Culver City, Calif. The devices are used to treat a rare disorder of the placenta in women pregnant with identical twins.

HDEs are granted under the FDA's humanitarian use device (HUD) program. The exemption allows devices to be distributed in the U.S. more quickly by cutting down on the waiting period for product approval. Fetoscopes are used to treat twin-to-twin transfusion syndrome (TTTS).

The instrument sets include a fetoscope -- a telescopic camera used to view the fetus -- and sheaths used to pass other surgical instruments and fluid through the surgical entry site. A laser to eradicate shared vessels during these procedures has already been cleared for marketing.

The HUD program encourages companies to develop medical devices to diagnose or treat diseases or conditions that affect fewer than 4,000 people in the U.S. per year. To receive HDE approval, a sponsor must demonstrate the safety and probable benefit of the device. HDE-approved products can be used only under the supervision of a local institutional review board (IRB).

Usually diagnosed at or shortly before birth, symptoms of TTTS include unequal size of twins, paleness in the smaller twin and redness in the larger twin.

In TTTS, the blood begins to flow unevenly, with one fetal twin -- the recipient -- receiving too much blood, and the other -- the donor -- receiving too little blood. This can cause heart failure in the recipient and life-threatening anemia in the donor. Many of these babies do not survive delivery or are born with severe disabilities.

The donor is usually born smaller and dehydrated, while the recipient is born larger with too much blood volume and increased blood pressure. Depending on the severity of the condition, the donor may need a blood transfusion and the recipient a blood volume reduction.

"This medical device gives doctors a new option for treating twin-to-twin transfusion syndrome," said Daniel Schultz, director of the FDA's Center for Devices and Radiological Health. "It can help prolong the mother's pregnancy and improve the odds of survival, with reduced complications, for one or both twins."

The devices are limited to use on fetuses whose gestational age is between 16 and 26 weeks, the FDA said. The device should not be used under certain conditions such as ruptured or infected membranes, or when the placenta is separated from the uterus, the agency noted.