Women do not fare worse than men after lumbar fusion surgery: Two-year-follow up results from 4,780 prospectively collected patients in the Swedish National Spine Register with lumbar degenerative disc disease and chronic low back pain

BACKGROUND CONTEXT: Proper patient selection is of outmost importance in surgical treatment of degenerative disc disease (DDD) with chronic low back pain (CLBP). Among other factors gender was previously found to influence lumbar fusion surgery outcome.

PURPOSE: This study investigates whether gender affects clinical outcome after lumbar fusion.

STUDY DESIGN: National registry cohort study PATIENT SAMPLE: Between 2001 and 2011, 2251 men and 2521 women were followed prospectively within the Swedish National Spine Registry (SWESPINE) after lumbar fusion surgery for DDD and CLBP.

OUTCOME MEASURES: Patient-reported outcome measures (PROM) visual analogue scale (VAS) for leg and back pain, Oswestry Disability Index (ODI), quality-of-life (QoL) parameter EQ5D and labour status and pain medication were collected preoperatively, 1 and 2 years after surgery.

METHODS: Gender-differences of baseline data and PROM improvement from baseline were analysed. The effect of gender on clinically important improvement of PROM was determined in a multivariate logistic regression model. Furthermore, gender-related differences in return-to-work were investigated.

RESULTS: Preoperatively women had worse leg pain (p<0.001), back pain (p=0.002), lower QoL (p<0.001) and greater disability than men (p=0.001). Postoperatively women presented greater improvement 2 years from baseline for pain, function and QoL (all p<0.01). Women had better chances of a clinically important improvement than men for leg pain (OR=1.39, 95% C.I.: 1.19-1.61, p<0.01) and back pain (OR=1.20,95% C.I.:1.03-1.40, p=0.02) as well as ODI (OR=1.24, 95% C.I.:1.05-1.47, p=0.01), but improved at a slower pace in leg pain (p<0.001), back pain (p=0.009), and disability (p=0.008). No gender differences were found in QoL and return-to-work at 2 years postoperatively.

CONCLUSIONS: Swedish women do not have worse results than men after spinal fusion surgery. Female patients present with worse pain and function preoperatively, but improve more than men do after surgery.