MMP9 and Nasal polyposis: They went further to perform another prospective study on 36 patients undergoing functional ESS for CRS or nasal polyposis, and found that nasal fluid MMP-9 can predict healing outcome after surgery and that high concentrations of MMP-9 post-operatively were associated with poor healing [106], suggesting a potential role for quantifying MMP-9 in the prognostication of CRS.