Preventing postsurgical tissue 'gluing.'

Preventing postsurgical tissue 'gluing'

"It's very common for women who have had gynecological [surgery] to experience increasing pelvic pain as they grow older," says Eugene P. Goldberg, director of the University of Florida's Biomedical Engineering Center in Gainesville. Most learn their pain results from "adhesions" -- patches of tissue that respond to abrasion from gauze, sponges and surgical instruments by fusing to each other during the normal wound healing process. White these adhesions can cause decades of discomfort, they usually do not threaten life.

The same is not true of adhesions that develop in patients surviving open-heart surgery, Goldberg notes. Adhesions in the membrane lining the heart can not only seriously compromise heart function but also complicate the physician's job -- and the chances of survival -- if the patient needs surgery again. And roughly 70 percent of abdominal-surgery survivors develop adhesions, which can prove similarly lethal if they cause intestinal blockages that are not surgically corrected.

Goldberg and his co-workers now report that hyaluronic acid, a natural, biodegradable constituent of cell membranes, can ward off adhesions in animals when applied to healthy internal tissues that will be exposed to surgical implements when surgery starts.

Hyaluronic acid coatings limited adhesion development to between zero and 20 percent of treated rats in one series of tests involving more than 350 animals. In contrast, 50 to 75 percent of the rats whose tissues were merely irrigated with Ringer's lactate -- a standard technique -- developed serious adhesions. In a related series of studies involving 60 dogs undergoing cardiac surgery, the results were more striking: zero adhesions in one hyaluronic acid group, compared with 100 percent adhesions for animals irrigated with Ringer's lactate.

"There are currently no clinically reliable local or systematic treatments for suppressing adhesion formation," Goldberg's group notes. However, hyaluronic acid "appears promising for the general prevention of surgical adhesions -- and especially for preventing adhesions of the fragile tissues of the abdominal and thoracic cavities." Goldberg notes that Boston-based Genzyme Corp.--which has a new process to produce the acid--will soon begin human trials.

Cataract surgeons use a gel-like form of the same substance when implanting synthetic lenses. But the 0.4 milliliter of 1 percent hyaluronic acid solution they use for each implantation comes from a rooster-comb extract and costs about $70. That would be prohibitively expensive for adhesion prevention, which may require a third of a liter of solution. Genzyme's new process should dramatically reduce hyaluronic acid's cost.