Evaluation of the Efficacy of Vacuum Sealing Drainage in Combination With Silver-Containing Dressings for the Improvement of Chronic Refractory Wounds

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Chronic refractory wounds refers to wounds that resist conventional, orderly, and timely healing processes or fail to return to their normal anatomical and functional state after attempted repair.^1,2 These wounds typically occur in patients with conditions such as pressure injuries, deep wounds, or diabetes. The characteristics of refractory wounds include exposure of deep tissues with poor blood circulation, the presence of foreign bodies or residual necrotic tissue, poor blood flow in the periwound, and concomitant pathogenic bacterial infection. Currently, the treatment of chronic refractory wounds remains a significant challenge in the field of plastic surgery.³ Clinical studies have highlighted the complexity of the pathogenesis of chronic refractory wounds. These wounds exhibit reduced neoangiogenesis, poor local blood supply, and intense inflammatory response compared to normal wounds. These factors collectively lead to a continuous state of tissue hypoxia in the affected area, resulting in prolonged healing time and an increased risk of scar formation or hypertrophic scarring.^4,5 In recent years, with the rapid development of the economy in China, an aging population, and the increasing prevalence of diabetes, pressure injuries, and vascular ulcers,⁶ the incidence of chronic refractory wounds stemming from these conditions has also risen, impacting quality of life for affected individuals.

At present, there are various clinical treatment options for chronic refractory wounds, including wound dressing, growth factor, vacuum sealing drainage, platelet-rich plasma, and surgical treatment (such as skin grafting and flap transplantation).^7,8 Surgical treatment is the most classic therapeutic approach, with the advantages of achieving a relatively good treatment outcome in a short period of time and a lower recurrence rate. Multiple studies have confirmed that tissue flap surgery can significantly improve the repair of and limb preservation rates in complex lower limb injuries.^9,10 However, the drawbacks are the surgical risks and significant trauma to the patient. Therefore, surgical treatment should be carefully weighed in terms of its pros and cons, with efforts made to minimize the treatment cost and preserve or reduce functional impairment.

While these measures do contribute to expediting wound healing to some extent, chronic refractory wounds often present with infections, necrotic tissue, and poor blood supply, leading to prolonged healing periods. Clinical research has predominantly focused on individual treatment modalities, with limited investigation of combination therapies. At present, vacuum sealing drainage has demonstrated significant value in improving the treatment outcomes of refractory wounds. This approach completely replaces traditional dressings, subjecting the entire wound uniformly to controlled pressure. Exudate from the wound is continuously collected in a vacuum pump, cleaning the wound of exudate and necrotic substance and reducing edema symptoms. Additionally, vacuum sealing drainage can exert traction on the wound, augmenting the blood supply, and ultimately facilitating wound healing. Xing et al¹¹ have indicated that compared to traditional treatment methods, vacuum sealing drainage technique can significantly reduce the length of stay of patients, improve wound healing rates, and have a positive impact on patient satisfaction. Zhang et al¹² have demonstrated that the vacuum sealing drainage technique can significantly enhance wound closure rates and effectively repair exposed wounds.

Silver ions have been proven to have good antibacterial effects. In recent years, there has been rapid development in new types of dressings. For example, silver-containing dressings not only have good moisture retention and moisture absorption but also exhibit minimal adherence to wounds, making them less prone to scab formation. Additionally, silver-containing dressings possessed anti-inflammatory and antibacterial effects. A study by Wang et al³ pointed out that silver-containing dressings can provide a moist environment for refractory wounds. The tiny pores in the dressing can form a gel after absorbing exudate, preventing the exudate from spreading and impregnating the surrounding healthy tissues, and the silver ions can protect exposed peripheral nerves, lock in the exudate, and promote a soft and moist closed environment, thus accelerating wound healing.

However, there are currently few clinical studies on the application of vacuum sealing drainage combined with silver-containing dressings in refractory wounds. The aim of this study was to investigate whether vacuum sealing drainage combined with silver-containing dressings could be used in chronic refractory wounds. The hypothesis was that the combined intervention could help accelerate wound healing, and a controlled group study was conducted based on this.  

General data

Eighty patients with chronic refractory wounds who were treated in the authors’ hospital from July 2020 to October 2022 were retrospectively selected as the study objects. Based on the treatment modalities, the patients were divided into the study group (SG; n = 40, receiving vacuum sealing drainage combined with silver-containing dressings) or the control group (CG; n = 40, receiving vacuum sealing drainage alone). This study received the approval from the Ethics Committee of Lanxi People's Hospital and followed the guidelines of Declaration of Helsinki. All study participants provided written informed consent before participating in the study.

Inclusion criteria consisted of (1) patients who underwent conventional debridement and anti-inflammatory treatment in the authors’ medical facility for 4 weeks without wound healing, and were diagnosed with chronic refractory wounds; (2) patients with complete patient information available from the hospital information system, including basic information, laboratory detection indicators before and after treatment, and clinical efficacy; (3) patients without hematological diseases; (4) patients who were hospitalized for treatment; and (5) patients with complete 14-day follow-up data.

Exclusion criteria consisted of (1) patients with concurrent immune system diseases; (2) patients complicated with severe liver and kidney dysfunctions; (3) pregnant or lactating women; (4) patients with bleeding tendency; (5) patients with severe malnutrition; and (6) patients with concurrent psychiatric disorders.

Intervention methods

After admission, both groups received routine periwound cleaning, antibiotics, nutritional support, fluid infusion and other treatment. Clinicians conducting operational treatment had to have properly credentials (ie, licensed practicing physicians).

The CG was treated with vacuum sealing drainage as routine treatment. After cleaning the wound skin, polyvinyl alcohol sponges were used to cover the wound surface. The vacuum sealing drainage device (Guangdong HongKing Medical Devices Co., Ltd.) was connected, the pressure was set to -16.6 kpa (approximately -125 mmHg), and the time of continuous suction intervention was 7 days. Throughout the treatment period, saline was used once daily for rinsing and draining the dressings.

The specific measures in the SG were as follows: After cleaning the wound, hydrophilic fiber silver-containing dressings of the appropriate size were cut according to the patient’s wound shape, and the silver-containing dressings included silicone tubes, which were covered to the wound surfaces, closed with a transparent film, and connected to the vacuum sealing drainage device, with the settings the same as those of the CG.

Sample size

Sample size was determined based on the formula: Sample size = [Max (dimensionality) × (10-20)] × [1+(10% - 20%)], and considering the scale with the most dimensions, which is the Vancouver Scar Scale containing 4 dimensions, the authors arrived at a recommended sample size range of 80-150 cases. To account for an anticipated 20% loss to follow-up, a final sample size of 160 cases was determined, taking into consideration both research needs and actual conditions, with a sample size of 80 cases in each group. The study sample population was patients with chronic refractory wounds.

Observation indicators and evaluation standards

The case collection period spanned from July 2020 to October 2022, with the deadline for collecting patient information set for November 14, 2022. The cutoff time for data collection was established as 14 days after the last patient received treatment. Patient observation indicators were obtained from the hospital information system as follows:

(1) Clinical efficacy. The healing of the wound or the entire epithelialization of the wound was regarded as a significant effect. A wound reduction of more than 50% after 14 days of treatment was classified as effective, while a wound reduction of less than 50% after 14 days of treatment was considered ineffective. The total number of effective cases was calculated as the sum of significant effect and effective cases.¹³

(2) The frequencies of dressing changes, length of stay, and hospitalization expenses of patients were collected from the system and compared between the 2 groups.

(3) The positive rate of wound bacteria culture, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) level were compared between the groups before and after treatment.

(4) The pain intensity of the 2 groups was compared and evaluated by visual analogue scale.¹⁴ The scale included a 0-10 cm straight line, where 0 represented no pain and 10 represented severe pain, and subjects selected a number to represent their pain intensity according to their conditions.

(5) Wound scar indicators were compared between the groups before and after treatment. The wound scar indicators were evaluated utilizing Vancouver Scar Scale ¹⁵ including four dimensions; namely, thickness (0-3 scores, with a 0 score indicating normal skin, and a score of 3 indicating 5 mm thicker than normal skin), color (0-3 scores), tenderness (0-4 scores), and vascular distribution (0-3 scores), with higher scores indicating severe scar hypertrophy.

Statistical methods

SPSS 28.0 was used to analyze the collected data. The counting data were presented as rate (%), and the χ² test were used. The measurement data were presented as (x̄±s), and the t-test was used. P < .05 was considered statistically significant.

Comparison of general clinical data

The general clinical data—including gender, average age, wound area, etiology, and wound site—were collected for both groups and compared. The results indicated no statistically significant differences in the above data between the two groups (P > .05), as shown in Table 1.

Comparison of clinical treatment efficacy

In the SG, there were 12 cases with significant effect, 26 effective cases, and 3 ineffective cases. The total effective rate was 92.5% (37/40), which was significantly higher than that of 75% (30/40) in the CG (P < 0.05), as shown in Table 2 and Figure 1.

Comparison of clinical indicators

In the SG, the average frequency of dressing changes was 5.10 ± 1.69 (Figure 2A) and the average length of stay was 20.15 ± 5.11 days (Figure 2B), which were lower than those in the CG (P < .05). The hospitalization expenses (Figure 2C) showed no significant difference between the 2 groups (P > .05), as shown in Table 3 and Figure 2.

Comparison of wound infection indicators before and after treatment

There was no significant difference in the positive rate of bacterial culture, CRP level, and ESR level between the 2 groups before treatment (P > .05). After treatment, the positive rate of bacterial culture, CRP level, and ESR level were decreased compared with those before treatment (P < .05). Moreover, after treatment, the positive rate of bacterial culture, CRP level, and ESR level in the SG were lower than those in the CG (P < .05), as shown in Table 4, Figure 3, and Figure 4.

Comparison of pain intensity before and after treatment

For days 0 through 5 of treatment, there was no significant difference in pain intensity score between the 2 groups (P > .05). However, starting at day 6 and continuing through day 14 of treatment, the pain intensity score in the SG was significantly lower than that in the CG (P < .05), as shown in Figure 5.

Comparison of wound scar indicators before and after treatment

The differences in the indicators of wound scars between the groups before treatment—including thickness, color, tenderness, and vascular distribution—were not statistically significant (P > .05). After treatment, the dimension scores were significantly decreased compared with those before treatment (P < .05), and the dimension scores in the SG were significantly lower than those in the CG after treatment (P < .05), as shown in Figure 6.

In recent years, advances in medical technology have led to the successful treatment of various diseases, but chronic refractory wounds remain a global challenge, greatly impacting the physical and mental health of patients and societal progress.¹ It has been observed in practice that the rapid development of China has significantly changed the dietary patterns of citizens, resulting in reduced physical activity, increased consumption of high-calorie foods, and the emerging trend of an aging population—all of which have collectively created conditions conducive to the development of chronic refractory wounds.¹⁷ The primary causes of chronic refractory wounds include diabetic ulcers, radiation ulcers, wounds, and malignant tumors, which often occur in people with senility and metabolic diseases. Wounds in people in these groups are often difficult to heal due to poor blood supply, infection, low concentration of growth factor locally promoting tissue repair, residual necrotic tissue, and other issues. Conventional debridement and dressing changes are often insufficient for promoting wound healing, necessitating long hospital stays and technical treatments such as multiple dressing changes and vacuum sealing drainage. However, even with these interventions, some patients still progress to adverse outcomes, including deformities, disability, and amputation.^18,19

In this study, the clinical value of vacuum sealing drainage combined with silver-containing dressings in the treatment of refractory wounds was analyzed retrospectively. The results showed that in terms of clinical efficacy, the effective rate of patients in the SG with combined intervention was significantly higher than that in the CG (92.5% vs 75%), which suggested the positive treatment efficacy of the combined intervention. Lv et al²⁰ conducted a controlled study on 120 patients with chronic refractory wounds and found that the total effective rate of patients in the control group receiving conventional vacuum sealing drainage treatment was 70.7% (41/58), which was significantly lower than the 91.9% (57/62) of patients in the observation group with silver-containing dressings. After 10 courses of treatment of a 45-year-old patient with type 2 diabetes, Anzali et al²¹ also found that the application of silver-containing dressings on refractory wounds had a positive effect. Vacuum sealing drainage is a novel technique that promotes wound healing and is frequently used in clinical settings for patients with conditions such as diabetic foot ulcers and burns, possessing advantages such as reducing tissue swelling and avoiding exacerbation of wound damage. However, vacuum sealing drainage alone also has disadvantages; that is, the application of foam materials may be wizened, affecting drainage effectiveness and patient prognosis. In the present study, the silver-containing dressings applied in the SG have many hydrophilic fibers and strong adsorption capacity. Silver ions have a good bactericidal effect; in addition, silver-containing dressings can protect healing wounds from the influence of wound secretions, reduce the risk of cross infection, and finally achieve the purpose of improving clinical efficacy. This was evident in the lower frequency of dressing changes and shorter hospital stays in the SG compared to the CG.

In the present study, the wound infection indicators of the 2 groups before and after treatment were compared, and it was found that the positive rate of wound bacterial culture and the levels of CRP and ESR in the SG after treatment were lower than those in the CG. A previous study²² confirmed that after the formation of the wound, cells surrounding the wound were destroyed, resulting in tissue hypoxia and eventually infection, and the persistence of infection affected wound healing. While the silver-containing dressings used in patients of the study group by Wen et al had a good bactericide effect, they could reduce the local reaction of oxidative stress on the wound, improve the degree of inflammatory infiltration, and reduce the production of inflammatory factors, all of which laid a good foundation for wound healing.²³ Wu et al²⁴ revealed that silver-containing dressings could induce certain stimulation to the wound, exerting an inhibitory effect on epidermal cell proliferation, which facilitated the desiccation and drying of the wound. Moreover, the silver-containing dressings exhibited excellent hydrophilicity, enabling close contact with the wound and thereby reducing dead spaces. Additionally, their soft and moist characteristics contributed to the accelerated formation of granulation tissue, which played a positive role in reducing the pain caused by wound infection in patients. This aspect was also observed in the present study.

Finally, the wound scar indicators of the 2 groups were compared, and the results indicated that the SG had significantly lower scores for thickness, color, tenderness, and vascular distribution compared to the CG after treatment. This should be attributed to the waterproof material on the outer layer of silver-containing dressings, which effectively prevented pathogenic bacteria from entering the wound and aggravating infection.²⁵ Additionally, the vacuum sealing drainage technique dilated the capillaries of the wound granulation tissue, while the silver-containing dressings stimulated the connection formation of neovascularization endothelial cells.²⁶ Under the dual action, the wound microcirculation was effectively improved, and the wound healing process was accelerated.

The limitations of this study are that it was a single-center drug experiment with a small sample size. Additionally, as a retrospective study, it was not possible to collect patient wound tissue for staining observation.

The combination of vacuum sealing drainage and silver-containing dressings was effective in treating chronic refractory wounds, which is conducive to reducing the bacterial infection rate and pain intensity of the wound, improving inflammatory state, and accelerating wound healing. It has certain clinical application value and is recommended for clinical promotion. This study provides evidence for new measures for the treatment of patients with chronic refractory wounds through joint intervention measures, which can help improve the prognosis of patients with chronic refractory wounds.

In the future, it is recommended to conduct a long-term follow-up study on the combination of vacuum sealing drainage and silver-containing dressings for patients with chronic infection and refractory wounds through a large sample, multi-center, and high-quality randomized controlled experiment, which should provide more convincing experimental results.

Authors: Rentong Ye, MB; Liang Ni, MB; and Qianyu Cheng, MB

Affiliation: Department of Plastic Burn and Wound Repair, Lanxi People's Hospital, Jinhua, Zhejiang, China

Disclosure: The authors disclose no financial or other conflicts of interest.

Correspondence: Qianyu Cheng, Department of Plastic Burn and Wound Repair, Lanxi People's Hospital, No.1359, Xishan Road, Lanxi City, Jinhua City, Zhejiang Province, 321100, China; Chengqianyu2023@163.com

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