Can a within/between-session change in pain during reassessment predict outcome using a manual therapy intervention in patients with mechanical low back pain?

The purposes of the study were to determine whether the combined occurrence of within/between-session changes were significantly associated with functional outcomes, pain, and self-report of recovery in patients at discharge who were treated with manual therapy for low back pain. A secondary purpose was to determine the extent of change needed for the within/between-session change with association to function. The study involved 100 subjects who were part of a randomized controlled trial that examined manual therapy techniques who demonstrated a positive response to manual therapy during the initial assessment. Within- and between-session findings (within/between session) were defined as a change in pain report from baseline to after the second physiotherapy visit. Within/between-session changes were analyzed for associations between pain change scores at discharge, rate of recovery, and a 50% reduction of the Oswestry disability index (ODI) by discharge. The results suggest there is a significant association between a within/between-session change after the second physiotherapy visit and discharge outcomes for pain and ODI in this sample of patients who received a manual therapy intervention. A 2-point change or greater on an 11-point scale is associated with functional recovery at discharge and accurately described the outcome in 67% of the cases. This is the first study that has shown an association of within/between-session changes with disability scores at discharge and is the first to define the extent of change necessary for prognosis of an outcome. A within/between-session change should be considered as a complimentary artifact along with other examination findings during clinical decision making.