I cannot thank you enough for the rapid reply with such good information. Read your very explanatory articles you referred us to. My husband has seen two different spine surgeons and the interventionist (radiology), had a general epidural and bilateral L4L5 facet joint injections, with worsening symptoms. Not one has done flexion extension X-rays or explained that Degenerative Spondylolisthesis is most likely the problem given his symptoms which seem to exactly correlate with the ones you listed. He is calling his GP today to obtain flexion extension X-rays and we will be sending these along with the MRI and an EOS imaging scan, and paying for your opinion regarding these. Again, thank you so very much. Melanie and Jim.