Lumbar muscle endurance tests, pain and disability in subjects with symptomatic spondylolisthesis. A cross-sectional diagnostic test study

Background and Aim – Spondylolisthesis is defined as a displacement of a vertebra over the one below, following structural and/or degenerative spinal changes. This displacement can provoke segmental dysfunction and modify the biomechanics of the spine. The Supine Bridge Test (SBT) and the Prone Bridge Test (PBT) are clinical tests commonly used to detect lumbar muscle endurance dysfunction in common Low Back Pain, but their validity was not yet tested in subjects with symptomatic spondylolisthesis. The aim of this study was to investigate the diagnostic accuracy of two clinical tests used to assess lumbar muscle endurance, in subjects with symptomatic spondylolisthesis. Materials and Methods – This study involved three different centers specialized in lumbar diseases rehabilitation. 112 consecutive patients with symptomatic spondylolisthesis were included. Prone and Supine Bridge Test were performed before the first session of rehabilitation. The results of these tests were compared with the Numerical Rating Scale (NRS) for pain intensity and the Oswestry Disability Index (ODI) for disability. Correlations between muscle endurance tests, NRS and ODI were calculated. Furthermore, correlations between results of endurance tests, grade of spondylolisthesis and positive results on dynamic X-rays were investigated. Results – The Prone Bridge test was moderately correlated with the Supine Bridge Test (r = 0.483, p<0.01) whilst both endurance tests showed low correlations with NRS (SBT r = -0,274; PBT r = -0,155) and ODI (SBT r = -0.341; PBT r = -0,284). Moreover, significant correlations between the endurance tests and the grade of the spondylolisthesis, or the positive dynamic X-rays were not found. Discussion – This study shows a moderate relationship between the two muscle endurance tests, but a week relationship between these tests, pain and disability, in symptomatic spondylolisthesis. The grade of spondylolisthesis or positive result on dynamic X-rays do not significantly influence these findings. Conclusion - The results of this study suggest a low diagnostic accuracy of SBT and PBT in patients complaining of symptomatic spondylolisthesis.