Medical Textiles Research at

NC State University Critical for Improving Suture Procedures

            “The life of the patient hangs by a thread.” With this phrase, Dr. Bhupender S. Gupta, professor of textile engineering, chemistry and science at NC State University, explained the importance of his work designing more secure sutures for surgical procedures.

                Closing wounds by placing a knot in a suture loop is a tedious process. The surgeon must make sure the knot won’t come undone before the tissues are healed. In critical surgeries such as open heart procedures, a slipped suture can be life threatening and could mean a dangerous emergency surgery for a patient. Surgeons typically tie sutures with four to five “throws,” or knot loops, to ensure security. For an open heart procedure that involves very many sutures, this is a time-consuming process.

                In addition to being time consuming, four-to-five-throw knots have other disadvantages. They present more foreign body material during healing, the patient must be kept under anesthesia longer during suturing and patients will have more pain from a bulky knot.

                According to Gupta, surgeons want to “tie a secure knot in the shortest time with the least material.” A knot with two throws would be very efficient if a way could be found to make the structure secure. Gupta decided to accept this challenge, and his research group has devised a way to make a two-throw knot fully secure using lasers.

                Gupta’s graduate students tied hundreds of knots using synthetic suture threads, then exposed the knots to carbon dioxide laser beams of varying intensities for various time periods. By examining the knots using an electron microscope, the researchers can see which of the fibers are melted into a secure unit.

                Using the lasers for this purpose is tricky, because the goal is to melt the surface only enough to cause bonding of the fibers without damage. Too much laser exposure can cause the fibers to become brittle and fragile, and the beam must be narrow and fine enough to hit only the desired area of the knot. By testing the variables of time and energy, the researchers can determine the optimum amount of each to create a perfect, secure, two-throw knot.

            Gupta’s research has shown the feasibility of this technique, but the technology needs to be refined so the laser beam is narrower and finer. “At this point,” said Gupta, “industry will have to come in and optimize the procedure.” Existing lasers present in hospitals may be able to be modified by moving the lens arrangement and diverting the beam. One early use of the new suture technique may be in eye surgeries, because lasers are commonly used for these procedures already.

                The importance of medical textiles expands beyond suture techniques. According to Gupta, textiles can be formed to have the same characteristics as tissues. They can stretch and have strength and elasticity. They can have porosity that aids in healing. In the future arteries and veins, for example, may be made from textiles. “We are learning to engineer the structures of human body organs,” said Gupta. The field is interdisciplinary and requires collaboration among faculty from several disciplines, in particular engineering, life sciences and medicine. The benefit to patients of this kind of medical textile research is enormous.