PREPARE (PREhabilitation, Physical Activity and ExeRcisE) persons with severe low back pain for an optimal functional outcome after lumbar fusion surgery

INTERVENTION: 1. Group A (n=55) will receive specific guidance from a physiotherapist on how to stay active despite pain based on cognitive behavioral therapy (CBT) principles. 2. Group B (n=55) will receive treatment as usual (general advice to stay active before surgery, and to make contact with a physical therapy for further guidance). CONDITION: Severe low back pain (disc degenerative disease) ; Musculoskeletal Diseases ; Other specified intervertebral disc degeneration PRIMARY OUTCOME: Disability measured by Oswestry Disability Index (ODI). SECONDARY OUTCOME: 1. Patient Specific Function Scale will be used to measure patients' own functioning goal. ; 2. Physical activity levels (sitting/lying and time spent upright) will be measured by the movement registration system Actigraph (uniaxial accelerometer). ; 3. The Pain Catastrophising Scale (PCS). ; 4. Zung Self‐Rating Depression Scale (Zung). ; 5. Functional performance testing: five‐minute walking, 50‐ft (15 m) fast walking, sit to stand, 1‐min stair‐climbing.; 6. The Swedish version of Tampa Scale of Kinesiophobia (TSK‐SV) questionnaire. ; 7. Self‐Efficacy for Exercise (SEE) self‐report scale to measure self‐efficacy for exercise in nine specific situations.; 8. European Quality of Life 5 Dimensions Questionnaire (EuroQol/EQ‐5D) (mobility, self‐care, usual activity, pain/discomfort and anxiety/depression). ; 9. Patients’ self‐report the effect of treatment (surgery) measured by Global Assessment. ; 10. The patients perceived harmfulness of daily activities will be measured by Photographs of Daily Activities (PHODA). ; 11. Cost‐effectiveness will be measured by estimating quality of life before and after the treatment (EQ‐5D), the number of quality adjusted‐life‐years (QALY) will be calculated. Days of sick‐leave will be collected from the Social Security Office. The days of hospital stay as well as number of health‐care consultation will be collected through the patients’ charts in addition to the patient’s own recording. INCLUSION CRITERIA: Swedish speaking patients with persistent LBP scheduled for surgical intervention attached to the Orthopedic Department at Sahlgrenska University Hospital or Spine Center, Gothenburg