Predictors for work incapacity continuing after disc surgery

Objectives This study was carried out to provide information on and identify factors about the fitness for work 12 months after disc herniation surgery. In addition a predictive tool for this outcome was developed. Methods A selected patient population (N=177) operated on for lumbar disc herniation from September 1995 until May 1996 was evaluated by medical advisers of a sickness fund. The patients were submitted to a standardized interview about their personal, social, medical, professional, and psychological status. To assess the functional status of the lumbar spine, a standardized clinical examination was used. Results Eighty-five percent of the patients were employed 1 year after surgery. The most important predictors at 6 weeks after intervention were the estimation of pain according to a visual analogue scale, the patient's prediction of his possibilities to resume work, the Oswestry disability index score, and the Zung depression score. Of the clinical factors, nonorganic signs and sensory disturbances after surgery were negative prognosticators for longlasting disability. Using the Oswestry score, the Zung score, the patient's own prediction, the score on the Social Readjustment Rating Scale, and the score on the Modified Somatic Perception Questionnaire, 86% of the poor outcomes could be correctly classified. Conclusions The Oswestry disability scale and the Zung depression scale should be included in the routine postoperative assessment after disc surgery and the patient's own prediction of his possibility for fitness for work should be taken seriously. If a poor outcome is predicted, the patient is in need of rehabilitation and should be guided more intensely.