Doctors are working on a new fix for cleft palate (search), a common birth defect in which children are born with a gap in the roof of the mouth.

One out of every 700 to 1,000 children in the U.S. is born with cleft palate. The problem starts during pregnancy when the roof of a baby’s mouth — the palate — doesn’t develop properly. An opening called a cleft is left in the mouth’s roof and may reach the nasal cavity. Cleft palate may occur by itself, or it may be accompanied by other birth defects of the face and skull, such as cleft lip.

Surgery can treat cleft palate. But until surgery is done, cleft palate can interfere with feeding, speech development, and hearing. Still, the surgery isn’t perfect, say Mayo Clinic researchers, in a news release.

According to the release, surgery sews the tissue flaps on the mouth’s roof over the cleft. But the technique doesn’t repair the missing bone. That can leave part of the mouth’s hard palate bone exposed, which may produce scars that complicate facial development.

Such growth impairment can cause cosmetic problems and make it harder for the upper and lower teeth to close together properly. There is also a risk of the wound splitting open or an abnormal passageway forming between the mouth and nose. Surgery may also shorten or scar the mouth’s soft palate, which could cause speech problems.

Mayo Clinic doctors are trying another approach. They’re testing a special device to stretch the hard palate bone and close the cleft.

The device consists of a central body piece, four plates, and screws. It’s surgically inserted under anesthesia. After about 10 days, a key is turned slightly each day for around four weeks. Turning the key applies tension to slowly lengthen the hard palate bone and soft tissue, closing the cleft.

The same technique — called distraction osteogenesis — is already used on people for other facial bone problems and in other parts of the body. But it hasn’t been used in cleft palate, says the Mayo Clinic’s Eric Moore, MD, in the news release.

So far, the device has been tested on eight hound dogs, due to similarities to the human mouth. The keys were turned 1 millimeter per day for 14 days. Afterwards, the device was removed and the tissue flaps were closed.

Five dogs’ clefts closed completely; two others improved. No dogs had any complications.

The results were “promising,” say the researchers, reporting their findings at last weekend’s Triological Society meeting in Chicago.

“This has positive implications for the shape of the palate and for speech later,” says Bob Tibesar, MD, in the news release. Tibesar worked on the study and is the chief resident of the Mayo Clinic’s otorhinolaryngology department.

The device isn’t ready for human use yet. It’s too bulky, so the doctors are testing a more delicate model, says Moore.

By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCES: The Triological Society, Middle Section Meeting, Chicago, Jan. 21-23, 2005. WebMD Medical Reference from Healthwise: “Cleft Palate — Topic Overview.” News release, Mayo Clinic.