Arthur Coury is president-elect of the Society for Biomaterials and vice president of research at Focal, Inc., a developer of surgical adhesives. Here is his reply.

There are more than four million surgical procedures performed annually worldwide. When traditional sutures and staples are used to seal a wound, post operative complications resulting from air and fluid leaks are not uncommon. Such air and fluid leaks can delay recovery, lead to higher levels of post operative pain and infection and precipitate other serious or life-threatening complications.

Even when surgeons use sutures and staples that can be absorbed naturally by the body, leaking at the wound site can occur because, regardless of their composition, sutures and staples do not have inherent sealing capabilities. As there is no standard treatment for these leaks, surgeons have long considered them to be an unavoidable consequence and have developed ways to manage them.

For instance, when surgical leaks on the lungs cause air to seep into the chest cavity, doctors insert chest tubes approximately one-half inch in diameter between the ribs and through the chest wall to draw out the potentially harmful buildup of air. Not only does this procedure create discomfort for the patient and affect his or her quality of life during recovery, but it also creates sites of possible infection--namely, the exit points of the tubes.

Patients with air and fluid leaks require more care than other patients while in the hospital, and they must remain hospitalized until the leaks are sealed. This prolonged hospitalization, as well as additional surgical procedures that may be needed for persistent leaks, results in substantial additional health care costs.

For years, surgeons have sought a substance that could create an air tight seal over a surgical wound. Since the early 1980s, efforts have focused almost exclusively on developing naturally derived products that control surgical bleeding. These compounds are typically based on a blood component called fibrin, which is extracted from humans or animals. But because such products, called fibrin glues, are designed specifically to control bleeding, they have limited effectiveness in forming a leak proof seal.

Another problem with fibrin glues is that many wrongly believe such blood products have the potential to transmit disease. Although numerous studies have shown otherwise, the effectiveness of these products has not been compelling enough to override lingering concerns. Even so, fibrin glues garnered a 10 percent share of the $2-billion worldwide wound-closure market last year--primarily because nothing better was available.

Recently, cyanoacrylate glues, found in most superglues, have made news. These materials, though, are not flexible enough to withstand the strain of an expanding organ surface and, quite literally, crack under pressure. Thus, the use of surgical superglues has been largely limited to sealing superficial skin wounds. As an alternative to painful stitching, the glues offer an especially useful option when treating young children.

My company has developed a surgical sealant, called FocalSeal, that is 95 percent water and based on synthetic polymer technology much like that used to make contact lenses. The sealant gel adheres rapidly to underlying tissue, expands and contracts with a moving surface and can withstand air and fluid pressure. Furthermore, it remains intact during the healing period and is then absorbed and eliminated by the body naturally. Because the sealant contains only man-made polymers, its function and behavior can be controlled and the risk of disease transmission is eliminated.

A surgeon applies the sealant in the form of a liquid, using a simple brush and syringe system. A specially designed light source then transforms the liquid into an adherent gel in the body, creating a leak-proof seal. The whole process takes minutes. The sealant is currently available in Europe for use in lung surgery. And products now under development are expected to be used in other forms of surgery, including neurosurgery, cardiovascular and gastrointestinal surgery.