A prospective study of patients with sciatica. A comparison between conservatively treated patients and patients who have undergone operation, Part I: Patient characteristics and differences between groups. Based on a prospective study on 342 sciatica patients examined with rhizography, the aim was to determine which factors others than the rhizography finding and the grade and duration of symptoms were related to the selection of patients to undergo operation. Compared with surgically treated patients, conservatively treated patients who did not undergo operation and who had pathologic rhizography findings had pessimistic attitudes to possible surgery, often expressed a desire to retire, and considered their work as physically stressful. The women in this group were older and had lower pain indices than women who underwent operation. Conservatively treated patients with negative rhizography had more severe occupational handicaps, minor expectations of possible surgery, physically more strenuous jobs requiring difficult physical positions, and lower indices for pain and ADL than did the operated patients. The social and ergonomic background problems are emphasized in sciatica patients conservatively treated after rhizography. 