The use of negative pressure therapy for the treatment Of lower-extremity wounds.

The use of negative pressure therapy for the treatmen Of lower-extremity wounds.

Atef Elsayed Emam¹, Abdel Naser Khallaf², Attia Mohamed Attia¹

CorrespondingAuthor:

Attia Mohamed Attia,

E-mail: Attiamohamedattia0@gmail.com

(1) Plastic and reconstructive surgery, Military Medical Academy.

(2) Plastic and Burn surgery Department, Faculty of Medicine, Al-Azhar University, Cairo, Egypt.

Copyright 2020 The Authors published by Al-Azhar University, Faculty of Medicine, Cairo, Egypt. All rights reserved. This an open-access article distributed under the legal terms, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in anyway or used commercially.

doi:10.21608/aimj.2020.24523.1151

Abstract

Background: lower extremity wounds with exposed bone, tendon or orthopedic hardware present a difficult treatment challenge.

Objective: The purpose of this study is to assess the role of the vacuum assisted closure (VAC) therapy in the management of lower extremity wounds.

Material and methods: A prospective analytic cohort study was conducted among 15 patient referred for reconstruction of lower extremity wounds. The study was conducted between January 2019 to June 2019. The wounds were inspected, surgical debridement was done if needed, and the VAC dressings were changed every 72 hours. Primary outcome was wound healing and granulation tissue formation. Secondary outcome was wound infection and wound size.

Results: Vacuum- assisted closure therapy greatly decreases the surface area of the wound.  Profuse granulation tissue formed rapidly, covering the bone and hardware. There was no statistically significant difference between the included patients regarding the pattern of wound infection pre and after negative pressure therapy (p=0.655). Results were both functionally and aesthetically satisfactory.

Conclusion: VAC therapy appears to be a simple and more effective than conventional dressings for the management of difficult wound in terms of reduction in wound volume, depth, treatment duration and cost minimize the number of local and free-flap transfers.

Key words:  VAC, NPWT, Lower Extremity wounds, Complex wounds.

Introduction

Delayed wound healing particularly in difficult wounds and in elderly with co morbidities is a major concern. It leads to the pain, morbidity, prolonged treatment, and require major reconstructive surgery which imposes enormous social and financial burden. Vacuum-assisted closure (VAC) is an alternative method of wound management, which uses the negative pressure to prepare the wound for spontaneous healing or by lesser reconstructive options. Method of VAC application includes thorough debridement, adequate haemostasis and application of sterile foams dressing ¹.

Negative-pressure therapy has been used in clinical applications since the 1940s and has increased in popularity over the last decade. Topical negative pressure is a relatively new concept. Other terminology used for this technique is vacuum-assisted closure ¹⁷.

The technique entails an open cell foam dressing put into the wound cavity, connecting it to a vacuum pump with a tube and covering it with an adhesive drape. A controlled continuous or intermittent sub-atmospheric pressure of 125 mmHg is applied. Documented evidence of the effectiveness of vacuum-assisted closure in acute wounds has been obtained from a pig model ¹⁰.

Vacuum assisted closure has been applied by many clinicians to chronic wounds in humans. Animal experiments showed that the pressure applied to create a suction force removes excess fluid, and debris, decreases tissue bacterial levels and increases tissue perfusion, which results in improved wound healing ⁵.

Complex wounds are defined as lesions that take a long time to heal, fail to heal or recur. They are very common in industrialized countries and cause significant pain and discomfort. The true incidence and economic impact of chronic wounds are difficult to assess because of the wide range of causative diseases and available treatment options¹⁶. 

Non-healing wounds affect about 3 to 6 million people in the United States, with persons 65 years and older accounting for 85% of these events. Non-healing wounds result in enormous health care expenditures, with the total cost estimated at more than $3 billion per year ¹².

 In this study the author assess the role of the vacuum assisted closure (VAC) therapy in the management of lower extremity wounds.

Material And Methods

Study design:

This study is a prospective cohort study, consisted of 15 patients who were subjected for reconstruction of lower extremity wounds.

 The study was conducted between January 2019 and June 2019. This study has been executed at the Plastic Surgery Department, El helmeya Armed Forces Hospital, Plastic and reconstructive department and Sayed Galal University Hospitals, Faculty of Medicine, Al-Azhar University, Cairo, Egypt.

Inclusion Criteria:

Patients aged more than 18 years old with Lower extremity wounds in an anatomical position feasible for creating an air-tight seal for NPWT.

Exclusion Criteria:

Patients aged less than 18 years old with complex wound anywhere other than lower limb. All patients gave written informed consent.

Ethical approval:

An approved was obtained from the Ethical Research Board (ERB) of the Faculty of Medicine, Al-Azhar University, Cairo, Egypt. Prior to study proceeding, all patients assigned informed consents after the obvious explanation of the possible adverse events.

VAC procedure :

Any dressings from the wound were removed and discarded. A swab for microbiology culture and sensitivity was taken before wound irrigation with normal saline. In case of necrotic tissues surgical debridement was done, and adequate haemostasis was achieved (Figure 1A,1B).

Prior to application of the drape, it was essential to prepare the peri-wound skin and ensure that it was dry.

Sterile, double layers of 1 cm thickness open-pore foam into which was embedded an evacuation tube of 16 or 18 Fr. were gently placed into the wound cavity. Then the tube was connected to a container of vacuum pump.

The site was then sealed with an adhesive drape covering the foam and all around the tube and at least three to five centimeters of the surrounding healthy tissue to ensure an airtight seal. Controlled intermittent pressure was applied to the wound.

The vacuum pump delivers a negative pressure of −125mmHg. The cycle was of one hour on and one hour off.

After the VAC dressing changed. The wound was washed thoroughly with normal saline, antiseptic solution and VAC was re-applied in most cases at bedside. The same routine was continued until full healing or satisfactory clean, granulating wound bed was obtained for Skin grafting or local flap. Figure (2, 3 &4).

Data were collected and Demographic information collected includes age, sex and co-morbid condition. Information noted for wound includes site and etiology of the wound, size before and after application of VAC.

Mean, frequency, ratio and percentages were calculated and data were inference also in the form of tables.

Statistical analysis of the data:-

Statistical analysis was performed using SPSS software version 23 for Windows (SPSS Inc., Chicago, IL, USA). The figures were renovated using GraphPad Prism (GraphPad Software, Inc, San Diego) software version 7. Continuous non-normally distributed data were reported using median and range. Subsequently, categorical variables were expressed using number and percentage and paired categorical data were compared using Wilcoxon Signed Ranks Test. The overall statistically significant difference was established at p < 0.05.

Figure 1 (A & B)

Figure 2 (A & B)

Figure 2 (C, D& E)

Figure 3 (A, B, C, D, E & F)

Figure 4  (A, B, C, D, E & F)

Table (1)  Figure legend:

Results

The study was conducted for fifteen patients with complex wounds admitted to the Elhelmeya Armed Forces Hospital, Plastic and Reconstructive surgery department.

The study included 9 males (60%) and 6 females (40%). with a median age of 27 (6-55) years. Out of the included patients, there were three (20%) patients suffered from diabetes, a case (6.6%) of systemic lupus erythematosus, and three (20%) hypertensive cases. (Table 2, Figure 5 and 6). There were 8 (53.3%) patients had lower extremity wound as a result of trauma. Additionally, two (13.3%) patients had lower limb wound as a result of diabetic foot, whereby one (6.6%) patient had such wound as a sequel of fascio-cutaneous flap failure. Eventually, two (13.3%) patients had lower extremity wound after abscess drainage, whereas one (6.6%) case had lower limb wound as a result of cellulitis (Table 3, Figure 7). In our cohort, the median wound size was 15 (3-30) cm2. In this concern, the most common wound site was the foot, 6 (40%) cases, thigh 4 (26.6) cases and legs 3 (20%) cases, respectively. There were an equal proportion of patients who had knee and ankle wound, (6.6%). Figures 8, 9 and Table 4). Pre-negative pressure therapy, there were 8 (53.3%) patients with positive wound infection. After such therapy, one of them (6.6%) experienced negative wound infection, whereas 7 (46.6%) cases still had positive wound infection. There was no statistically significant difference between the included patients regarding the pattern of wound infection pre and after negative pressure therapy (p=0.655) (Table 5).

As for the fate of wound after negative pressure therapy, one case (6.6%) experienced spontaneous healing of the wound, whereas nine (60%) and five (33.33%) cases necessitated graft and flap at the site of the wound, respectively. (Figure 10 and Table 6).

Figure (5): Distribution of studied sample according to sex.

Figure (6): Histogram displayed the age distribution among the included patients

Figure (7): Bar chart displayed causes of lower extremity wounds among the included patients

Figure (8): Histogram displayed the size of wounds among the included patients

Figure (9): Pie chart displayed the site of the wound among the included patients

Figure (10): Pie chart displayed the fate of wounds after negative pressure therapy among the included patients

Table (2): Distribution of studied sample according to demographic data (n=15)

Table (3): The causes of lower extremity wound

Table (4): The sites of lower extremity wounds

Table (5): The pattern of wound infection pre and after negative pressure therapy.

Table (6): The fate of wounds after negative pressure therapy