Evaluation of the protease-modulating effect of negative pressure wound therapy and standard wound care in pressure injury of spinal cord injury patients

Introduction: We studied the relationship of pressure injury (PI) matrix metalloproteinase-8 with healing rate in spinal cord injury patients (SCI) patients. Our aim was to assess the surface area and depth of PI, exudate amount, tissue type and level of MMP-8 in PI treated with negative pressure wound therapy (NPWT) and PI treated with dry gauze dressing as standard wound care.

Material and Methods:A cohort of 44 SCI patients having stage III/IV sacral PI were randomized into two groups: one (n=21) - received NPWT with a locally constructed negative pressure device (NPD), and other (n=23) - received dry gauze dressing as a standard wound care. The PI was treated until the wound closure or up to 9 weeks. Levels of MMP-8 were analyzed at week 0, 3, 6 and week 9 by ELISA. 

Results: Significant lower level of MMP-8 was observed in NPWT group at week 6 and week 9 as compared to standard care group. Significant reduced surface area was observed in PI of NPWT group at week 6 (p=0.04) and week 9 (p=0.001). Significant reduction of depth of PI was also observed in NPWT group at week 9 (p<0.05). Pierson’s correlation analysis showed significant positive correlation of MMP-8 with surface area and depth at week 0, 3, 6 and week 9 in NPWT group. In contrast to NPWT group, significant negative correlation of MMP-8 was observed with surface area and depth at week 0, 3, 6 and week 9. Exudate levels became significantly (p=0.001) lower in NPWT group compared to standard care from week 3. Conversion of slough into granulation tissue was significantly higher in NPWT group after week 6 (p=0.001).

Conclusions: Levels of MMP-8 can be used to indicate the prognosis of PI and NPWT used to improve healing rates as a protease modulating treatment.