Outcomes research represents un expansion of traditiorial clinical research to include issues ~f c o s t
and quuliv of care in usual clinical practice, emphasizing outcomes that matter most to patients. In low back disorders, outcomes reseurch hns focused on the lack of reliable information to support much o f clinical practice and has demonstrated murked variability in the treatment of these coinmoil problems. The Muine Lumbar Spine Study represents an exumple of an outcomes research study to investigute the treutment of patients with sciatica in usual clinical practice. Because low back symptoms are a frequent cause of occupational rlisability. Workers ' Compensation putirnts were explicitly oversumpled. Baseline features were significnntly diflerent in those patients who were receiving Workers' Compensation versus tlzose who were not. Eforts to compare outcomes by disability status need to control for these differences. Whereas most Workers' Compensation patients were still receiving tiisability c'nmperzsation regardless of treutment ut 6 months, patients who were treated surgically were more likely to have come ojf disubili@ and returned to work than rionsurgically treuted patients. Long-term follow-up is necessary to determine nlhether these dif-,ferences persist. 0 1996 Wile,vl.iss, Iric.