Are prognostic factors still what they are expected to be after long-term follow-up?

The aim of this prospective study of 121 patients was to investigate whether or not the predicting factors of lumbar disc surgery become lost over an increased follow-up time. Preoperatively, the patients classified their pain on the visual analogue scale, and general data, case histories, and neurologic findings were recorded. Follow-up examinations were carried out at 3, 12, and 28 months. At the 3-month follow-up examination, six predictive factors were calculated, after 1 year there were only four, and after 28 months only two predictive factors were found. After reviewing these results, it was apparent that the number of prognostic factors diminished over time. To obtain reliable surgery-related results for the prognostic factors in lumbar disc surgery, we believe that the follow-up period should not exceed 1 year.