Anxiety and its predictive value for pain and regular analgesic intake after lumbar disc surgery - a prospective observational longitudinal study

BACKGROUND Ongoing pain after surgery is a major problem and influences recovery and the quality of life of the patient. Associations between anxiety and their impact on postoperative pain after herniated disc surgery have been reported, but the results are inconsistent. The aim of the present longitudinal study was to evaluate the predictive value of preoperative anxiety for postoperative ongoing pain and prolonged analgesic intake after herniated disc surgery. METHODS 106 patients with lumbar disc herniation were evaluated in the study. Anxiety was measured with the Generalized Anxiety Disorder 7-Item Scale (GAD-7) before surgery. Pain intensity was assessed on a numeric rating scale (NRS) at baseline, 6-weeks and 6-months after surgery. Regression analysis was performed to identify independent predictors of pain and regular utilization of analgesics up to 6 months after surgery while controlling for confounding variables. RESULTS 42.5% of the patients were rated as anxiety cases (sum scores GAD-7 > 5), mean scores of anxiety showed mild to moderate symptom severity, and 43% suffered from chronic pain before surgery. Six months after surgery, 55.6% of the patients indicated pain levels of 4/10 (NRS) or higher and about 40% still took pain medication on a regular basis, regardless of their preoperative classification as anxiety-case (37.7% and 41.5%). The preoperative pain level was statistically significant for ongoing postsurgical pain in all four analyses (p < 0.001). With binary logistic regression analyses, preoperative pain intensity, but neither demographic factors nor preoperative anxiety, was identified as predictor for postoperative pain and need for analgesic medication up to 6 months after lumbar disc surgery. CONCLUSION We found no evidence for the presence of anxiety before disc surgery being a prognostic factor for ongoing pain and regular postoperative intake of analgesics. Only preoperative pain intensity was predictive for increased pain and continued need for analgesic medication up to 6 months after lumbar disc surgery. TRIAL REGISTRATION Clinicaltrials.gov NCT01488617 . Registered 6 December 2011.