Use of pain medication before and after lumbar discectomy: longitudinal analysis of a nation-wide cohort

BACKGROUND: Previous studies have suggested that variation in results of lumbar discectomy depends on careful selection of patients. Numerous factors have been suggested to explain this variation with no direct examinations on this issue. The objective was to examine the use of pain medication before and after lumbar discectomy in patients with back pain. METHODS: Prospective occupational cohort study (n=151 618) with linkage to national registers. Of the cohort members, 1 538 (age 44 years) underwent discectomy. Records from purchases of pain medication were obtained during a 3-year period before and after hospital discharge. RESULTS: Purchases of pain medication increased during the follow-up period from 9.7 (SD=28.7) to 17.3 (SD=17.3) defined daily doses. Three groups were identified: 1) with constant, relatively low pain medication use; 2) with high use combined with further increases in purchases until the time of surgery and only a slight decrease thereafter; and 3) with a sharp rise in medication use before surgery and a return to no pain medication use approximately six months after the discharge. Non- manual profession (OR 1.34, 95% CI 1.06 to1.69) and open surgery technique increased (OR 1.32, 95% CI 1.04 to 1.67) the probability of being included into the third group. CONCLUSIONS: The greater decline in the use of pain medication after discectomy was associated with a sharp rise of that use within six months before surgery. This suggests that lumbar discectomy may benefit especially those with acute or subacute pain within the six-month window