Do changes in transversus abdominis and lumbar multifidus during conservative treatment explain changes in clinical outcomes related to non-specific low back pain?

Research that has been conducted in the past describes a relation between temporal changes in transversus abdominis or lumbar multifidus and temporal changes in clinical outcomes that is inconsistent. Unfortunately, a relevant systematic review is not available. Because of this, this systematic review was designed to summarize evidence related to the association between temporal changes in muscle morphometry and activity in response to treatment and temporal changes in clinical outcomes. They located candidate publications from six electronic databases. Fifteen articles were included after careful examination by two reviewers using the predetermined selection criteria. The methodological quality of the articles chosen was appraised using a standard tool. These methods uncovered strong evidence that temporal alterations in transversus abdominis thickness change during contraction (as measured by B-mode or M-mode ultrasound) or feedforward activation of transversus abdominis (assessed via electromyography, tissue Doppler imaging or M-mode ultrasound) were unrelated to temporal changes in LBP/LBP-related disability. There was limited evidence that temporal changes in transversus abdominis lateral sliding or lumbar multifidus endurance weren’t related to temporal changes in LBP intensity. They uncovered evidence found for the relation between temporal changes in lumbar multifidus morphometry and temporal changes in LBP/LBP-related disability that was contradictory. Their review highlights that temporal changes in transversus abdominis features are usually unrelated to the corresponding LBP/LBP-related disability improvements while the connection between multifidus changes and clinical improvements is still uncertain.

Their systematic review highlighted that changes in morphometry or activation of transversus abdominis following conservative treatments  are usually not associated with the corresponding changes in clinical outcomes. However, the association between post-treatment changes in characteristics of lumbar multifidus and clinical improvements is still unclear.