The FDA has approved a humanitarian device exemption (HDE) for fetoscopy instrument sets distributed by Karl Storz Endoscopy America (Culver City, California) under the Humanitarian Use Device (HUD) program for the treatment of fetuses with twin-to-twin transfusion syndrome (TTTS).

TTTS, according to the FDA, is a rare disorder of the placenta that sometimes occurs when women are pregnant with identical twins. In TTTS, during the development of the twins, blood vessels in the fetuses' shared placenta connect their blood circulations. In most cases, the blood flows properly through these vessels.

However, in TTTS, the blood begins to flow unevenly, with one fetal twin receiving too much blood, which is called the "recipient," and one receiving too little, the so-called "donor."

The FDA said that many of such TTTS babies do not survive delivery or are born with severe handicaps.

"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, in an agency statement. "It can help prolong the mother's pregnancy and improve the odds of survival, with reduced complications, for one or both twins."

A Karl Storz spokesman told Diagnostics & Imaging Week that the system is actually a device set of instruments, called a "fetoscopy instrument set." It consists of a fetoscope, which is one of the company's endoscopes with a light attached that is used to view the fetus. The endoscope also includes a sheath which is used to enter the abdomen of the mother through a small incision. That incision is used to pass through surgical instruments and, if necessary, any fluid.

The device set is intended for use for fetuses whose gestational age is between 16 and 26 weeks.

"That's sort of the access point," the spokesman said. "This is minimally invasive, of course."

The third component of the procedure, which is not carried out by the instrument set, is a laser, previously FDA-approved, that can be used as a "heat source to coagulate tissue, and this is what actually forms the treatment for this condition," he said.

Essentially, while being guided by ultrasound in the woman's abdomen, the physician can determine exactly where the problem blood vessels involved in TTTS are located.

"Once they identify those, they can insert the laser and they use the photocoagulation function to heat up the tissue, and this essentially destroys a portion of the blood vessel, which is how they treat the condition," the company spokesman said.

The Karl Storz spokesperson said that in terms of marketing, there would not be an effort to market to "every physician, gynecologist or obstetrician."

Since the HUD program encourages the development of medical devices intended to treat or diagnose a disease or condition affecting fewer than 4,000 people in the U.S. per year – and since the HUD exemption was just provided – Jaffy said that no marketing of the device set has yet been done.

According to the FDA, to receive approval of an HDE application, a sponsor must demonstrate the safety and probable benefit of a device. Such products can only be used under the supervision of a local Institutional Review Board.

Until now, there really were no other options for treatment of the condition, the company said. Although there have been some treatments involving the exchange of amniotic fluid, "those have not provided a whole lot of hope for the parents."

According to consumer information provided on its web site for the device, the FDA said the Karl Storz Fetoscopy Instrument Set should not be used when a variety of conditions exist. These include ruptured membranes; infection of the membranes or placenta; placenta separation from the uterus; or active labor.