MMP13 and spinal stenosis: The mean density (arbitrary units) of active MMP-2 and MMP-13 was statistically higher in the spinal stenosis specimens than that in the disc herniation specimens (324.75 ± 63.66 vs. 238.00 ± 76.05, respectively, p < 0.05; 340.00 ± 48.63 vs. 248.50 ± 52.09, respectively, p < 0.05).