In-Spec 2200 testing apparatus (Instron Corporation, Norwood, Massachusetts).
Athre RS, Park J, Leach JL. The Effect of a Hydrogen Peroxide Wound Care Regimen on Tensile Strength of Suture. Arch Facial Plast Surg. 2007;9(4):281-284. doi:10.1001/archfaci.9.4.281
Author Affiliations: Department of Otolaryngology–Head and Neck Surgery, The University of Texas, Southwestern Medical Center, Dallas (Drs Athre and Leach); and Department of Biomedical Engineering, University of Texas, Austin (Dr Park).
Correspondence: Raghu S. Athre, MD, Department of Otolaryngology–Head and Neck Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75230 (firstname.lastname@example.org).
Objective To compare the tensile strength of nylon, polypropylene, and fast-absorbing gut sutures treated with either 3% hydrogen peroxide or water for a period of 5 days to emulate a wound care regimen.
Methods An In-Spec 2200 bench-top tester was used to find the maximum load that a particular suture could sustain prior to breaking.
Results Analysis of the data showed a statistically significant decrease in tensile strength of fast-absorbing gut sutures treated with hydrogen peroxide compared with fast-absorbing gut suture control samples and fast-absorbing gut sutures treated with only water.
Conclusion Though no in vivo studies were performed, a logical extension of these results would be that premature degradation of fast-absorbing gut sutures secondary to use of hydrogen peroxide might lead to widened and/or hypertrophic scars.
Suturing is a critical function in almost all surgical procedures. The use of suture and the process of suturing have been described in Egyptian scrolls dating from 3500 bce. The most primitive sutures included silk, leather, and even vegetable fibers.1 Suture design has evolved a great deal since ancient times, and surgeons now have a wide variety of suture options to choose from for closing wounds. The choice of an appropriate suture for a particular situation can be based on objective criteria, such as absorbability and other physical and/or chemical properties of the suture, and on subjective criteria, such as surgeon preference.
Following surgical closure, the physician has as many choices of wound care regimens as there are possible suture types. The substances used in superficial wound care regimens include water, soapy water, bacitracin, mupirocin calcium cream (Bactroban; GlaxoSmithKline, Brentford, England), hydrogen peroxide, Dakin solution, and any of a variety of combinations of these regimens. Wound care regimens are also selected based on objective and subjective criteria. Objective considerations include open vs closed wound and cellular toxic effects of the wound care agent; subjectively, surgeon preference and previous experience may contribute to the decision-making process.
Despite the numerous suture and wound care regimen choices, there is a lack of scientific data proving that any particular suture or wound care regimen is vastly superior to another. The present study was suggested by an observation in postsurgical patients after they had undergone surgical treatment for head and/or neck cancer. Owing to the equivalent scar profile of absorbable suture and permanent suture, and the ability of the surgeon to conserve time and minimize patient anxiety by using absorbable suture, most surgical patients have the superficial layer of their surgical wounds closed with 5-0 fast-absorbing gut suture.1-2 The main criterion for this decision is surgeon preference. At 1-week follow-up, a subset of these patients show dehiscence of the most superficial layer of skin closure. The superficial epidermis pulls apart, and no evidence of the fast-absorbing gut sutures can be found. The separated wound closes by secondary intention over the ensuing 3 to 4 weeks without significant complications. Extensive questioning of these patients reveals that most of them used hydrogen peroxide to clean their wounds postoperatively. The question of whether hydrogen peroxide affects the tensile strength of fast-absorbing gut sutures by increasing its degradation rate became the focus of this study.
Fifteen samples of 5-0 fast-absorbing gut, 5-0 nylon, and 5-0 polypropylene sutures (Prolene) were obtained from Ethicon Inc, Piscataway, New Jersey. These were the same sutures sold to hospitals and other buyers of medical supplies. All suture package expiration dates were checked to ensure that the products were still viable.
All suture packages were opened on day 0. Five samples of each type of suture were randomized to the control group, 5 to the water group, and 5 to the peroxide group. Control suture was not manipulated in any way. Suture samples randomized to the water and peroxide groups were dipped in the appropriate solutions twice a day for 5 minutes each time for a total of 5 days to simulate a wound care regimen. For example, 5-0 nylon suture in the peroxide group was dipped in htdrogen peroxide twice a day (at 8 am and 6 pm) for 5 days. The peroxide and water solutions consisted of over-the-counter 3% hydrogen peroxide and distilled water, respectively.
At the end of 5 days, all suture samples were subjected to tensile strength testing using a bench-top In-Spec 2200 (Instron Corporation, Norwood, Massachusetts) portable bench-top tester. The In-Spec machine consisted of 2 jaws that were mobile along a metal rail. The suture sample was attached to the 2 jaws, with the jaws being 10 cm apart. The machine was subsequently triggered, and the jaws would begin to pull apart until the suture broke. The In-Spec machine output variables included a graph of force vs length of stretch as well as the peak load in kilonewtons. A picture of the testing apparatus is shown in the Figure.
The peak load or breaking strength in kilonewtons was tabulated for each trial, and mean values were calculated for each group (eg, fast-absorbing gutcontrol, fast-absorbing gutwater, and fast-absorbing gutperoxide). The peak load was defined as the largest load value sustained by the suture prior to breaking. This value was used as an indicator of the tensile strength of the suture samples.
Following tabulation and calculation of mean values for each group, the Microsoft Excel 2000 statistical package (Redmond, Washington) was used to perform a t test to determine if performing the various wound care regimens resulted in a statistically significant change in the tensile strength of the suture. The assumptions for the t test included a 2-tailed t test with equal variance.
On preliminary visual examination, nylon and polypropylene sutures did not appear to be affected by either water or hydrogen peroxide. Both groups of suture samples retained their shape, color, and general feel when handled. The fast-absorbing gut suture, however, was different. The fast-absorbing gut suture subjected to water did not appear to be affected compared with control suture. The fast-absorbing gut suture subjected to hydrogen peroxide rinses completely disintegrated during handling. It could not hold any tension at all, and in 1 case, the hydrogen peroxide–treated suture had completely degraded; the only thing left behind was the needle. Samples were subjected to tensile strength testing as described in the “Methods” Section. Results are shown in Table 1.
In conclusion, application of hydrogen peroxide to the fast-absorbing gut suture resulted in a statistically significant decrease in the tensile strength of the suture compared with control samples (P = .002) and samples subjected to water alone (P<.001). Water and hydrogen peroxide regimens did not significantly affect the nylon and polypropylene sutures (Table 2).
Though wound closure and postoperative wound care regimens are the final steps of most surgical procedures, they are not the least important. The primary goals of wound closure include obliteration of dead space, approximation of wound edges to create a closed environment separate from the external environment, and maintenance of equally distributed tensile strength over the entire wound surface until tissue tensile strength is adequate to overcome external forces that act to pull the wound apart.3 Furthermore, creating a cosmetically appealing scar that does not affect form or function is as important. Complications such as wound infection, wound dehiscence, hypertrophic scars, and contractures may result from improper wound closure techniques, improper wound care regimens, and patient factors such as nutritional status and medical comorbidities.
Wound healing is the body's own defense response to tissue injury and is a complex, interrelated cascade of cellular and chemical events that act in unison to restore tensile strength and appearance of injured skin. Wound healing is usually described as occurring in 3 phases: inflammation, proliferation, and maturation. Though this model is simplistic and does not fully describe the interrelationships between the various phases, it does attempt to develop a framework to understand wound healing.
The inflammatory phase of wound healing is characterized by a vascular and cellular response to injury. Following injury, exposure of subendothelial collagen and release of neurotransmitters such as epinephrine, norepinephrine, and serotonin leads to aggregation of platelets (ie, the primary platelet plug). As platelets adhere to each other, they become activated and release chemotactic and growth factors. Concurrently, the coagulation cascade is activated by the intrinsic and extrinsic pathways. The net result of platelet aggregation and coagulation cascade activation is clot formation. The various chemotactic factors, prostaglandins, growth factors, and other chemicals that are released at the site of injury act to attract various inflammatory cells such as macrophages, T lymphocytes, and neutrophils. The inflammatory cells act to cleanse the site of injury, remove necrotic matter, release bacteriocidal free radicals, break down injured tissue, provide cellular and humoral immunity, and secrete substances to attract fibroblasts and angioblasts to the injured area.4
The proliferative phase follows the inflammatory phase and is marked by formation of granulation tissue, epithelialization, angiogenesis, and fibroplasia. Epithelialization is the formation of an epithelial cell layer over a surface. This layer occurs within 24 to 48 hours in most incisional wounds and provides a seal between the internal wound and the external environment. Fibroplasia involves the migration of fibroblasts to the injured area and initially starts about 3 to 5 days following injury. Fibroblasts deposit collagen into the wound; tension, pressure, and stress affect the rate of collagen synthesis.4
Finally, the maturation process is where the scar assumes its final form. Collagen remodeling and crosslinking along with removal of old collagen fibers allows the wound to evolve. Water is reabsorbed from the wound in this stage, which allows the collagen fibers to lie closer to each other and thus facilitates cross-linking and remodeling. Ultimately, this results in decreased scar thickness. The peak tensile strength of a wound occurs at approximately 60 days following injury, but the tensile strength of a healed skin wound will only reach 80% of the tensile strength of uninjured skin.4
An understanding of the basic steps involved in wound healing allows the surgeon to close wounds without complications, loss of function, or poor cosmetic outcomes. Similarly, the correct choice of suture is also critically important. Suture can be classified under 2 broad categories: absorbable and nonabsorbable. Absorbable suture provides a temporary support scaffold until the wound itself can support the normal stresses and strains of tissue. Absorption of such suture can occur by hydrolysis or enzymatic degradation.3 Examples of absorbable suture include polyglactin 910 (Vicryl; Ethicon), poliglecaprone 25 (Monocryl; Ethicon), polyglycolic acid (Dexon II; Kendall Co, Mansfield, Massachusetts), polydioxanone, gut, chromic gut, and fast-absorbing gut. The first stage of absorption occurs with linear kinetics and lasts from days to weeks, depending on the type of suture. The second stage of suture degradation, which overlaps the first stage, results in a loss of suture mass. Nonabsorbable suture provides a permanent support scaffold and elicits fibroblasts to encapsulate the stitches. Nonabsorbable suture is frequently used to close the most superficial layer of skin and is removed once healing has occurred but before excessive granulation tissue and scarring around the suture occurs (usually 6-8 days). Examples of nonabsorbable suture include silk, steel wire, polyamide polymer (Ethilon; Ethicon), polypropylene (Prolene), and polyester (Mersilene; Ethicon).3 In 1992, Guyuron and Vaughan2 showed that there was no statistically significant difference between absorbable and nonabsorbable suture used for superficial closure with respect to hypertrophic scarring.
The choices in wound care regimens are as varied as the choices in types of suture. Surgeon preference and surgeon training are most important in choosing among these numerous options. The focus of this article was to determine the effect of wound care regimens on the tensile strength of suture. One of the roles of suture is to provide tensile strength to hold the wound closed until the natural tissue mechanisms can heal the wound. Itwould follow that affecting the tensile strength of suture would affect the overall efficiency and outcome of wound healing.
The hypothesis in this experiment was that the use of hydrogen peroxide for superficial wound care caused premature breakdown of superficial fast-absorbing gut suture. This hypothesis was shown to be true: the tensile strength of fast-absorbing gut suture treated with the hydrogen peroxide regimen was significantly less than that of the control samples. Also, t test analysis showed the tensile strength of hydrogen peroxide–treated fast-absorbing gut suture to be significantly less than that of fast-absorbing gut suture treated with water alone. There were no significant differences in tensile strength in the case of nylon or polypropylene suture with respect to wound care regimen.
It follows that a loss in tensile strength of suture and widening of the wound incision line could lead to widened or hypertrophic scars. This was not observed in the patients who had premature degradation of their superficial skin suture. It is possible that an increased incidence of scarring and poor cosmetic outcome might have been observed if more patients were observed. The correlation between what happens in vivo and premature degradation of superficial skin suture was not studied in this experiment. This shortcoming could be addressed in future studies by recording and comparing scar results in patients with fast-absorbing gut suture used to close their wounds and who use a hydrogen peroxide postsurgical wound regimen. Another adjunct to this study could be an animal model where the tensile wound strength as a function of wound care regimen could be measured.
Despite the lack of objective evidence linking hydrogen peroxide use in patients with fast-absorbing gut suture and an increased incidence of scarring, the evidence from this study shows that hydrogen peroxide significantly decreases the tensile strength of fast-absorbing gut suture. Therefore, hydrogen peroxide should be avoided as a superficial wound care regimen when fast-absorbing gut suture is used for wound closure. Hydrogen peroxide does not affect the tensile strength of polypropylene or nylon suture.
Accepted for Publication: September 27, 2006.
Author Contributions:Study concept and design: Athre and Leach. Acquisition of data: Athre and Park. Analysis and interpretation of data: Athre and Leach. Drafting of the manuscript: Athre and Park. Critical revision of the manuscript for important intellectual content: Athre and Leach. Statistical analysis: Athre. Obtained funding: Athre. Administrative, technical, and material support: Athre and Park. Study supervision: Leach.
Financial Disclosure: None reported.
Additional Contributions: Danna Ward from Ethicon Inc provided free suture samples. Also, the Department of Biomedical Engineering at University of Texas, Austin, provided the facilities to test the suture in this experiment.