Predictors of persistent postoperative pain after surgery for idiopathic scoliosis

Purpose To identify factors contributing to persistent postoperative pain in patients treated surgically for idiopathic scoliosis. Methods In total, 280 patients aged ten through 25 years at surgery, were identified in the Swedish Spine registry; all having preoperative and postoperative visual analogue scale (VAS) for back pain scores. The patients were divided into a high and low postoperative pain group based on the reported postoperative VAS for back pain scores (by using 45 mm on the 0 mm to 100 mm VAS scale as a cut-off). The patient-reported questionnaire included VAS for back pain, the 3-level version of EuroQol 5-dimensional (EQ-5D-3L) instrument, the EuroQol VAS (EQ-VAS) and the Scoliosis Research Society 22r instrument (SRS-22r). Predictors of postoperative back pain were searched in the preoperative data. Results The 67 (24%) patients that reported high postoperative VAS back pain (> 45 mm) also reported lower postoperative EQ-5D-3L, EQ-VAS and SRS-22r than patients with low postoperative VAS back pain (all p < 0.001). Two preoperative variables were independently associated with postoperative pain; each millimetre increase in preoperative VAS back pain (on the 0 mm to 100 mm scale) was associated with a higher risk of being in the high postoperative back pain group (odds ratio (OR) 1.03; 95% confidence interval (CI) 1.02 to 1.05) and each 1 point decrease on the preoperative SRS-22r mental health (scale from 1 to 5) was associated with a higher risk of being in the high postoperative back pain group (OR 1.68; 95% CI 1.03 to 2.73). Conclusion High preoperative back pain and low preoperative mental health are independent predictors of back pain after surgery for idiopathic scoliosis.