Change in Granulation Tissue Coverage and Bacteriological Load Using Low Cost Negative Pressure Wound Therapy in Acute Musculoskeletal Wounds

Background: Low cost Negative Pressure Wound Therapy (NPWT) dressings have been considered as an alternative to traditional daily dressings. There is scanty literature evaluating the change in the percentage area of wound covered by granulation tissue following application of low-cost NPWT. The change in the bacteriological flora following application of low-cost NPWT devices has also not been evaluated.

Methods: Patients above the age of 18 years with acute musculoskeletal injuries of <3 weeks duration which underwent a surgical debridement and required subsequent wound coverage were included in the study. Area of the wound and the area covered by the granulation tissue as well as the bacteriological count were measured before and after application of NPWT. A low cost NPWT using wall mounted vacuum device was put on the patient giving a constant negative pressure of 125 mm of Hg for 2 days. The findings before and after application of NPWT were compared and analyzed using Wilcoxin Signed-rank test.

Results: 21 patients with mean age of 35.52±15.075 were included. The pre-NPWT granulation tissue area ranged from 122 mm to 8483 mm with a mean of 1648.38 mm (SD = 1933.866). The post-NPWT granulation tissue area ranged from 234 mm to 7847 mm with a mean of 2364.48 mm (SD = 1857.716). The mean increase in granulation tissue was 716.1 mm.The pre-NPWT wound area ranged from 422 mm to 10847 mm with a mean of 4009.62 mm (SD = 3026.209). The post-NPWT wound area ranged from 326 mm to 9143 mm with a mean of 3410.33 mm (SD = 2636.206). The mean reduction in wound size was 599.29 mm.The pre-NPWT bacteriological count ranged from 3000/ml to 130000000/ml with a mean of 12616761.90/ml (SD = 29664589.37). The post-NPWT bacteriological count ranged from 1000/ml to 380000000/ml with a mean of 26401523.81/ml. The mean increase in bacteriological count was 13784761.91/ml.

Conclusion: There was a statistically significant decrease in wound size (p = 0.001) and statistically significant increase in percentage area of granulation tissue coverage (p = 0.000) following low cost NPWT application. However there was no statistically significant increase in bacteriological clearance in these patients.