Commonly used woundcare products may compromise suture strength

Key Points

Researchers chose to study this topic because little research in this area exists, says Whitney Valins, a clinical research fellow working with Brian Berman, M.D., at the University of Miami Miller School of Medicine. Furthermore, Ms. Valins says lead study author Vidya Rajpara, M.D., also at the University of Miami, considers wound healing an important cosmetic issue.

"If the tensile strength (TS) of sutures is affected by woundcare products," Ms. Valins says, "the sutures could break, potentially leading to an increased risk of infection and less cosmetically acceptable healing."

TS reflects the weight necessary to break a suture divided by the suture's cross-sectional area in square millimeters, Ms. Valins says. Researchers used a tensometer to gauge the TS of several sutures commonly used in dermatologic surgery, both before and after seven days of continuous exposure to common woundcare products. The tensometer is a large device that essentially holds any material being studied between two grips then slowly pulls the grips apart at a measured rate until the material breaks, Ms. Valins says.

Sutures tested included nylon (4-0 and 6-0), polypropylene (4-0 and 6-0), polyglactine 910 (3-0 and 5-0), polydioxanone (3-0 and 5-0) and poliglecaprone 25 (3-0). Researchers incubated samples of each suture for seven days with each of three woundcare products: petrolatum ointment, triclosan antibacterial soap and hydrogen peroxide 3 percent.

After the incubation period, investigators measured the TS of each suture three times to account for possible suture material defects and to ensure the accuracy of tensometer readings, Ms. Valins says. They used unpaired t test analysis to compare individual sutures, as well as paired t test analysis to compare incubated sutures to baseline and to compare mean percentage reductions in suture strength versus baseline.

Results

At baseline, researchers found polypropylene sutures to be significantly stronger than nylon (P = 0.02 and 0.01), Ms. Valins says. Poliglecaprone was the strongest absorbable suture (p ≤ 0.001, versus polyglactine and polydioxanone). The weakest absorbable suture at baseline was polydioxanone.

After incubation, "We found that hydrogen peroxide statistically significantly decreased the TS of 4-0 nylon (p = 0.02), 3-0 polyglactine (p = 0.047) and 3-0 polydioxanone (p = 0.01) sutures. In addition, hydrogen peroxide led to very large reductions in the TS of the 4-0 and 6-0 nylon," she says.

Many of the other sutures retained 90 to 100 percent of their original TS after incubation, Ms. Valins says. "But after the nylon sutures were exposed to hydrogen peroxide, they retained only 35 percent to 40 percent of their TS (Rajpara V, Berman B, Viera M et al. Poster 307. American Academy of Dermatology 68th Annual Meeting; March 5-9, 2010; Miami Beach, Fla.)."

Researchers also found that petrolatum ointment had no significant effect on any of the sutures, a finding that supports the use of this material in woundcare after suture placement, Ms. Valins says. However, triclosan antibacterial soap decreased the TS of 4-0 nylon (p = 0.04), 3-0 polyglactine (p ≤ 0.001), 5-0 polydioxanone (P. = 0.04) and 3-0 poliglecaprone (P = 0.047) sutures. Conversely, Ms. Valins says, none of the products tested changed the tensile strength of polypropylene sutures analyzed.

"It was surprising that the hydrogen peroxide had a significant effect on the nylon sutures. Nylon sutures are commonly used for wound closure on the surface of the skin, so they are frequently exposed to woundcare products," she says.

Future studies

To more closely approximate real-world conditions, investigators are enrolling patients for a follow-up study in which they will examine the TS of sutures taken from Mohs and other surgical patients who have applied hydrogen peroxide to them, as this solution is normally used three times daily for a few seconds at a time, Ms. Valins says. For this study, she says investigators had to overcome the problem of how the tensometer would grip small pieces of suture.

"We had to make sure the suture would break rather than slipping out of the clips," she says. The follow-up study protocol will include approximately 40 patients and is expected to be completed in about three months.

Disclosures: Ms. Valins reports no relevant financial interests.