Objective: Assess the clinical improvement of patients undergoing decompression and posterolateral lumbar arthrodesis for degenerative diseases, evaluating the evolution of the scores of Oswestry 2.0 questionnaire and the physical component (PCS) of the SF-36 scale. Methods: Prospective study of 19 patients with degenerative disc disease (disc herniation, lumbar stenosis or degenerative spondylolisthesis) that underwent decompression and posterolateral arthrodesis. All patients included in our study answered the questionnaire Oswestry 2.0 and the PCS of SF-36 at five different occasions: in the preoperative period and 45, 90, 180 and 360 days after surgery. Results: The scores of Oswestry 2.0 questionnaire and the physical component (PCS) of the SF-36 of the patients showed significant improvement (p<0.001 and p=0.004 respectively) over a year of postoperative follow-up. 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