The quantification of low back disorder using motion measures - Methodology and validation

Study Design. Trunk angular motion features were used as a means to quantif y the extent of a low back disorder in healthy people and patients with chr onic low back disorders. Objective. To refine and validate a previously reported means of quantifyin g the extent of a low back disorder. Summary and Background. Many assessment tools of low back disorder are subj ective. A quantitative assessment tool would facilitate the tracking of the recovery and help document the appropriateness of treatments. Methods. The trunk motion characteristics of 374 healthy people and 335 pat ients with chronic low back disorders of varying severity were documented a s they flexed and extended their trunks in five different planes of motion. The trunk motion features were normalized as a function of age and gender. Four classification techniques were used to assess the ability of the quan titative motion measure to identify those with and without low back disorde rs. In addition, 31 patients were observed longitudinally to determine whet her the motion measures agreed with observed changes in back pain symptoms. Results. The quantitative trunk motion measure distinguished between people with low back disorders and healthy people between 88% and 94% of the time , depending on which classification system was used. Sensitivity and specif icity varied between 83% and 97%. The quantitative measure also showed prom ise as a means to distinguish between muscle-based and structure-based low back disorders. Prospective findings indicated that the quantification syst em agreed well with clinical observations of progress. Conclusions. The quantification of trunk motion can serve as a measure of t he extent of a low back disorder. When considered along with other clinical information, the ability to assess and treat low back disorders is enhance d.