Effects of limited access dressing in chronic wounds: A biochemical and histological study

Background: Negative pressure wound therapy has emerged as an attractive treatment modality for the management and healing of chronic ulcers. Though numerous clinical studies are available, there is a lack of biochemical and histological studies evaluating the healing of chronic wounds. Materials and Methods: In the present study, a total 60 patients were divided into two groups: Limited access dressing (LAD) group (n = 30) and conventional dressing group (n = 30). Various biochemical parameters such as hydroxyproline, total protein and antioxidants such as reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT) and oxidative biomarker malondialdhyde (MDA) are measured in the granulation tissue. Histologically amount of inflammatory infiltrate, angiogenesis, and collagen deposition are studied to assess wound healing. Results: Patients treated with LAD have shown significant increase in the mean (±standard deviation) hydroxyproline (77.3 ± 30.1 vs. 32.3 ± 16.18; P = 0.026), total protein (13.89 ± 9.0 vs. 8.9 ± 4.59; P = 0.004), GSH (7.4 ± 1.91 vs. 5.1 ± 1.28; P = 0.039), GPx (122.3 ± 59.3 vs. 88.7 ± 34.11; P = 0.030), CAT (1.80 ± 1.14 vs. 0.9 ± 0.71; P = 0.002) and decrease in MDA (13.4 ± 5.5 vs. 8.6 ± 3.8; P = 0.004). Histological study showed comparatively fewer inflammatory cells, increased and well organised collagen bundles, and more angiogenesis in the LAD group when compared with that with conventional dressing after 10 days of treatment. Conclusion: In the present study, we have found beneficial effect of newer intermittent negative pressure therapy in combination with moist environment (LAD) on chronic wound healing by increasing collagen deposition and angiogenesis; and reducing oxidative stress and inflammatory infiltrate.