The purpose of this randomized controlled trial was to determine the validity of a previously suggested clinical prediction rule (CPR) for identifying patients most likely to experience short-term success following lumbar stabilization exercises (LSE). Although LSE are often used by physical therapists in the management of low back pain (LBP), they do not appear to be more effective than other interventions. A 4-item CPR for identifying patients most likely to benefit from LSE has been previously suggested, but has yet to be validated. One hundred-five patients with LBP underwent a baseline examination to determine their status on the CPR (positive or negative). Patients were stratified by CPR status and then assigned at random to receive a LSE program or an intervention consisting of manual therapy (MT) and range of motion (ROM)/flexibility exercises. Both interventions included 11 treatment sessions administered over 8 weeks. LBP related disability was measured by the modified version of the Oswestry Disability Index (MODI) at baseline and upon completion of treatment. Results The statistical significance for the 2-way interaction between treatment group and CPR status for the level of disability at the end of the intervention was P=.17. However, among patients receiving LSE, those with a positive CPR status experienced less disability by the end of treatment compared with those with a negative CPR status (P=.02). Also, among patients with a positive CPR status, those receiving LSE experienced less disability by the end of treatment compared with those receiving MT (P=.03). In addition, there were main effects for treatment and CPR status. Patients receiving LSE experienced less disability by the end treatment compared with patients receiving MT (P=.05), and patients with a positive CPR status experienced less disability by the end treatment compared with patients with a negative CPR status, regardless of the treatment received (P=.04). When a modified version of the CPR (mCPR), containing only the presence of aberrant movement and a positive prone instability test (PIT) was used, a significant interaction with treatment was found for final disability (P=.02). Among patients receiving LSE, those with a positive mCPR status experienced less disability by the end of treatment compared with those with a negative mCPR status (P=.02), and among patients with a positive mCPR status those receiving LSE experienced less disability by the end of treatment compared with those receiving MT (P=.005).
The study was not able to validate the previously suggested CPR for identifying patients likely to benefit from LSE. However, because of the relatively low level of power this study should not invalidate the CPR either. A modified version of the CPR, containing only 2 of its items, may have a better predictive validity in identifying those most likely to succeed with a LSE program. As this modified version was established through post-hoc testing, the authors suggest an additional study is to prospectively test its predictive validity.