Chronic low back pain (with or without lower extremity pain) is extremely common problem in primary care and the leading cause worldwide for disability. Approximately 70 to 85% of the western population will develop low back pain at least once during their lifetime.~Low back pain is pain, muscle tension, or stiffness localized below the costal margin and above the inferior gluteal folds, with or without sciatica, and is defined as chronic when it persists for 12 weeks or more. The burden on the economy of low back pain were estimated at €2.6 billion and the direct medical costs at 6.1% of the total healthcare expenditure in Switzerland. Multiple modalities of treatments are utilized in managing chronic low back pain including analgesics, physiotherapy, injections, acupuncture, or surgery. Intralaminar and transforaminal lumbar epidural injections of corticosteroids have shown to be effective in patients with chronic low back pain and or leg pain.~Several studies demonstrated how patients' expectations are important predictors of the postsurgical health outcome. Patients' expectations are frequently studied as prognostic factors in knee and hip arthroplasty. It was shown that patients undergoing elective orthopaedic surgery whose expectations were fulfilled were found to be more satisfied with the overall treatment as compared to those whose expectations were not fulfilled. Furthermore, it was found that there is a robust small positive association between patients' positive preoperative expectations and better patient-reported postoperative outcomes. Investigators hypothesize that patient expectations of the pain treatment is also an important predictor of the pain reduction after epidural injections in patients with low back pain and/or leg pain. Therefore, the aim of this study is to investigate the prognostic significance of patient expectations on pain reduction after epidural injections in patients with low back pain and/or leg pain.
Investigators hypothesize that patients with higher expectations regarding their epidural injection experience a higher pain reduction of their lower back pain and/or leg pain after an epidural injection. Patients' expectations of an epidural injection can influence their level of pain reduction. The primary objective of this study is to investigate the prognostic significance of patient expectations on pain reduction after epidural injections ('expected benefits', see under) in patients with low back pain and/or leg pain.~Investigators furthermore hypothesize that patients that have a higher match between their expectations of improvement and actual improvement are more satisfied. A secondary objective of this study is to investigate the prognostic significance of a high match between expectations of improvement and actual improvement on patient satisfaction of the treatment.