Inclusion Criteria:  Patients diagnosed with Failed Back Surgery Syndrome and was admitted to Jaseng hospital of Korean medicine. Patients have agreed to participate the study. Patients who had participated "Long-term course of failed back surgery syndrome (FBSS) patients receiving integrative Korean medicine treatment: a 1 year prospective observational multicenter study" Patients aged 19-70 years on the date  Exclusion Criteria:  Patients who are difficult to complete the research participation agreement Other patients whose participation in the trial is judged by a researcher to be problematic