A Randomized Controlled Study Evaluating the Clinical Benefits of a Cellulose Acetate Mesh Coated with a Soft Silicone in the Management of Acute Wounds

Dressings are considered the mainstay for wound management. However, dressing adherence to the wound or periwound area is a common complication and can cause pain and trauma upon removal.^1-4 Commercialized nonadherent wound contact layer dressings have helped reduce wound bed trauma during dressing changes; they are used to protect tissue from direct contact with other agents or dressings applied to the wound and to minimize local wound pain during removal. These dressings may be particularly beneficial over vulnerable skin and painful wounds and may also help to protect exposed structures and newly formed granulation tissue.^5,6

Numerous options for nonadherent wound contact layers exist in the market. New dressings should show a similar or lower adherence risk than existing nonadherent dressings. This comparative, randomized controlled, open-label, noninferiority study examined the effects of a cellulose acetate mesh (CAM) coated with soft silicone (ADAPTIC TOUCH Non-Adhering Silicone Dressing; Systagenix, an Acelity Company, Gatwick, UK) against a flexible polyamide net (FPN) coated with soft silicone (Mepitel; Mölnlycke Health Care, Norcross, GA) in patients with acute wounds.

MATERIALS AND METHODS

Study design

Seventy patients were enrolled in this comparative, randomized controlled, open-label, noninferiority study between January 2012 and October 2013 spread across 12 sites with private nurses specialized in wound management. Patients were allocated to either the FPN group (n = 35) or the CAM group (n = 35) using 1:1 randomization; 1 patient was excluded from the CAM group due to not receiving the treatment/dressing. All patients provided written informed consent. This study was approved by the National Agency for the Safety of Medication and the Ethics Committee (Lyon, France, #2012-A00526-37).

Wound measurements were taken once per week for 4 weeks (Table 1). Wound photos and measurements were taken after dressing removal and prior to new dressing placement to allow for a blinded review of wound healing. Adverse events (AEs) were monitored by the investigators who were not blinded. Complete wound closure was reported as 100% reepithelialization of the wound without residual drainage or eschar and when no additional dressing protection was needed. 

Dressing adhesion was noted when dressing removal could not be performed smoothly without resistance, even after wound irrigation with sterile saline solution, or if there was wound bed bleeding or if the patient’s pain score using the visual analogue scale (VAS) post removal was ≥ 30 mm (moderate pain).^7-10 A wound contact layer dressing showed optimal efficiency if the following criteria was met: wound closure occurred within 4 weeks of study inclusion, all dressing applications and removals were considered easy and no adherence was noted, no dressing removal had induced a pain score of ≥ 30 mm, and no local dressing-related AEs were reported. 

Inclusion criteria

Adult patients aged ≥ 21 years with traumatic wounds, postsurgical wounds, wounds due to medical procedure, or acute burns and not participating in any other study were included. Acute burns included thermal burns, first-degree or second-degree burns, or burns not meeting any of the Burn Unit Referral Criteria from the French Society for the Study and Treatment of Burns nor requiring hospitalization. Wounds between 4 cm² and 30 cm² in size, located on the upper or lower limb or on the trunk, < 7 days old, and further than 3 cm away from any other wound were included. In addition, patients needed to be available for weekly follow-up visits over a 3-week period, use the VAS, have independent mobility, and move between a bed and chair with limited help.

Exclusion criteria

Individuals with objections to study participation or current participation in another study or whose health costs were not covered by social health security as well as women of reproductive age without contraceptive use were excluded from the study. In addition, bedridden or mobility-impaired patients and individuals with a comorbidity that could compromise the patient’s participation during the 3-week follow-up period were excluded from the study. Patients also were excluded if they had a known allergy to any of the study dressing ingredients, had an active malignancy or any pathology requiring radiotherapy and/or the use of cytotoxic agents, or had a concomitant severe trauma requiring physical or surgical management. The use of long-term oral or injectable corticosteroids at a high dosage (> 17 mg/k of methylprednisolone or equivalent) or chronic immunosuppressive agents also excluded patients from the study.

Wounds closed by suture, requiring a surgical procedure or tissue graft within the planned 3-week follow-up period, or showing clinical signs of infection (any aspect justifying the initiation of systemic antibiotics) were excluded. Neoplastic wounds (suspected or histologically confirmed), wounds not localized to the limbs or trunk, or wounds with edges < 3 cm from any other wounds also were excluded. If the target wound was a minor burn and the total burn surface area was > 10% of total body surface area, the patient was excluded from the study.

Dressing applications

Both types of nonadherent wound contact layer dressings were applied and changed according to the manufacturer’s instructions. All wounds were prepared according to standard of care wound management protocol. The surrounding periwound skin was dried and the nonadherent wound contact layer dressings were applied directly over the wound and smoothed in place to ensure a slight overlap of the dressing onto the periwound skin. A cover dressing (nonwoven absorbent sterile gauze secured with a net bandage) was applied to secure the contact layer dressing. Dressings were changed a minimum of once per week.

Statistical analysis

Descriptive statistics of patient demographics were performed. The full analysis set (FAS) included all of the randomized patients who had at least 1 assessment when the dressing was removed. All statistical analyses were performed using SAS version 9.2 (SAS Institute Inc, Cary, NC).

Primary endpoint

The primary endpoint was the proportion of patients who did not experience any adhesion of a nonadherent wound contact layer dressing during the 4-week monitoring period. 

The one-sided 95% confidence interval (CI) of the intergroup difference in percentage of patients without dressing adherence over the follow-up period was calculated. If the upper limit of this analysis fell strictly below the preset threshold of 10%, the noninferiority of the CAM dressing compared with the FPN dressing would be established. If the upper limit of the analysis were to fall strictly below 0, the superiority of the CAM dressing would be established.

Secondary endpoints

The secondary endpoints were the percentage of wounds completely reepithelialized within the 3-week follow-up period, median time until complete reepithelialization, and proportion of patients for whom the use of the provided dressing was of an optimal overall efficiency. Adverse events were recorded. 

The percentages of patients with complete reepithelialization and with optimal overall efficiency between the control and test dressings were compared using the Cochran-Mantel-Haenszel test taking the given dressing and the randomization strata. A P value > .05 meant the link between the treatment and complete reepithelialization was not statistically significant, even after the randomization strata had been adjusted.

Time to complete reepithelialization was analyzed using the Kaplan-Meier method and a log-rank test between the control and test dressing groups. The absolute and relative wound-surface differences between the 2 dressing groups were detailed. The absolute difference between the 2 groups was compared by means of a Mann-Whitney test.

RESULTS 

Patient demographics

Average patient age was 87.6 ± 6.4 years and average body mass index was 23.5 ± 3.6 kg/m². Women made up 71% of the total study population. Patient comorbidities included cardiac insufficiency (n = 20), eczema or asthma (n = 7), severe respiratory impairment (n = 4), and diabetes mellitus (type 1 or 2; n = 4) (Table 2). 

Baseline wound characteristics

Majority of the wounds occurred between 48 hours and 7 days prior to study inclusion (Table 3). The CAM dressing group contained 33 patients with a posttraumatic wound and 1 patient with a second-degree deep burn. One patient was excluded from the CAM group as the patient was randomized but did not receive any treatment or dressing removal assessment. The FPN dressing group contained 35 patients with a posttraumatic wound. Wound size ranged from 3.1 cm² to > 24 cm², with a majority of wounds sized between 4.1 cm² and 8.0 cm² (Table 3). The presence of slight wound exudate was observed in 18 CAM group wounds and 17 FPN wounds. Periwound skin showed some erythema and edema in both groups. Patient-reported baseline wound pain was 0.6 ± 1.2 for the CAM group and 0.7 ± 1.0 for the FPN group. 

Primary endpoint

In the CAM group, 33 of 34 (97.06%) patients did not experience dressing adherence during any assessment compared with 32 of 35 (91.43%) in the FPN group. The intergroup difference was -5.63% (asymptotic: 95% CI, -16.51%–5.24%). Since the upper limit fell below the 10% threshold, noninferiority of the test dressing was shown.

Patients in both groups underwent 3 dressing changes over the course of the study. Pain upon primary dressing removal was similar between the 2 groups at each dressing change (P > .05) (Table 4). Bleeding following dressing removal was noted in 9 CAM patients compared with 4 FPN patients; however, this was not statistically significant (P = .110). 

Secondary endpoints

Differences in time to complete reepithelialization were examined; time of injury was adjusted to the time of study inclusion. The number of patients whose wounds showed complete reepithelialization by ≤ 48 hours was similar between the 2 groups (8 CAM and 10 FPN). The number of patients whose wounds showed complete reepithelialization ranging from > 48 hours to 7 days was also similar between the 2 groups (17 CAM and 15 FPN). The link between treatment dressing type and complete reepithelialization was not statistically significant, even after adjustment for the time elapsed since injury (P = .8985).

The period leading up to complete reepithelialization was compared between the 2 groups (Figure). The length of time to complete reepithelialization was similar between the CAM dressing (average, 16 days) and the FPN dressing (average, 15 days) groups (P = .4958). Optimal overall effectiveness was examined between the 2 groups; both patient groups showed similar effectiveness (≤ 48 hours: 45.5% CAM vs. 53.3% FPN; 48 hours to 7 days: 55% CAM vs. 60% FPN; P = .6238). 

Adverse events

Six patients (2 CAM and 4 FPN) experienced a total of 9 AEs. Four system organ classes were affected: general disorders and administration site conditions (4 AEs, 4 patients); injury, poisoning, and procedural complications (2 AEs, 2 patients); respiratory, thoracic, and mediastinal disorders (2 AEs, 2 patients); and skin and subcutaneous tissue disorders (1 AE, 1 patient). These AEs were determined to be unrelated to treatment. There were 3 deaths during the study: 2 patients treated with CAM and 1 who received FPN. The investigators determined none of the deaths were associated with treatment.

DISCUSSION

The results herein showed the CAM dressing performed as well as the FPN dressing and was as clinically efficacious in reducing dressing-related trauma issues. At the time of the trial, the market price for the CAM dressing was lower than that of the current standard of care (FPN dressing), which could potentially provide cost savings; however, comparative economic studies between the FPN and CAM dressings are necessary.

Overall, the study population included primarily patients of advanced age. A majority of patients had wounds related to falls or episodes related to their age, including degloving wounds, dermabrasions, and 1 burn. Adverse events were observed in the study; however, these events, much like the wounds treated with the FPN dressings, were found to be associated with advanced age. None of the AEs were related to treatment.

Nonadherent wound contact layer dressings have been shown to minimize adherence to the wound bed and pain upon removal.^11-14 These dressings have become the standard of care as a protective layer in tandem with advanced wound treatments/therapies. Nonadherent wound contact layer dressings are used as a contact layer over skin substitutes or grafts^15,16 and between the wound and a negative pressure wound therapy dressing.^17-19 The superiority of the nonadherent CAM dressing was not shown. However, the CAM dressing performed as well as the FPN dressing in terms of adherence, rates of wound closure, and optimal effectiveness. Thus, the CAM dressing performed as well as the standard of care FPN dressing, supporting its use as a wound contact layer. 

LIMITATIONS

Adverse events were monitored by the investigators who were not blinded, which could have introduced bias into the study. Future research with larger sample sizes examining pain, dressing adherence (using standardized spring scale of tensiometer), and reinjury as separate endpoints are needed.

CONCLUSIONS

Wound dressing changes can be painful for patients as the dressings can adhere to the healing wound. In order to reduce this complication, nonadherent wound contact layer dressings are recommended to protect the wound from dressing adherence. This study indicated that the CAM dressing performed as well as the FPN wound contact layer dressing. 

Acknowledgments

Affiliations: Plastic Reconstructive and Aesthetic Plastic Surgeon, Lyon, France; Health Economics and Statistics, RCTs, Lyon, France; and Systagenix, an Acelity Company, Gargrave, UK

Correspondence: Lorraine Nisbet, BSc, Gargrave, North Yorkshire, BD23 3RX; Lorraine.Nisbet@acelity.com

Disclosure: Ms. Hoss, Dr. Cullen, and Ms. Nisbet are employees of Systagenix, an Acelity Company. The authors thank Julie M. Robertson (Acelity) for assistance with manuscript preparation and editing.

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