Provocative Walking Test of Strength for Diagnosis, Management, and Outcome Assessment of Symptomatic Lumbar Spinal Stenosis.

Background. Clinical care and randomized trials of rehabilitation or surgery for symptomatic lumbar spinal stenosis with neurogenic claudication (LSS) are complicated by the lack of standard criteria for diagnosis and outcome measurement. Objective. To evaluate whether manual muscle testing (MMT) can detect transient lower-extremity weakness provoked by walking in patients with likely LSS. Methods. A total of 19 patients with symptoms and MRI findings suggestive of LSS were tested for a decline in lower-extremity strength, using the British Medical Council scale of MMT, by comparing strength at rest to a change in strength within 60 s of completing a 400-foot walk. They were retested after reclining supine for another 2 minutes. This examination was repeated following decompressive lumbar surgery. Results. All patients developed bilateral weakness in the distribution of their LSS, but always including the hip extensors and knee flexors, when tested immediately after the provocative walking test. Most patients were not aware of weakness or change in gait during the walking task. They recovered to baseline strength after resting supine. The patients did not improve with physical therapy. When examined within 8 weeks after decompressive laminectomy, no one developed weakness during the 400-foot walk, and daily lower-extremity pain had resolved. Conclusions. A careful repetitive motor examination can detect transient paraparesis in patients with definite LSS. This finding supports the diagnosis and the functional severity of LSS while providing an objective outcome measurement for physical therapy and surgical interventions that goes beyond symptoms of pain.