Effect of Spinal Cord Stimulation on Early Disability Pension in 198 Failed Back Surgery Syndrome Patients: Case-Control Study

BACKGROUND Spinal cord stimulation (SCS) has proven to be a cost-effective treatment for failed back surgery syndrome (FBSS). However, the effect on patients' working capability remains unclear. OBJECTIVE To evaluate the impact of SCS on working capability and to identify the factors behind permanent disability in FBSS patients. METHODS The study group consisted of 198 working-age patients with SCS trialed or implanted for FBSS in a single center between 1996 and 2014. For each patient, 3 living controls, matched by age, gender, and birthplace, were otherwise randomly selected by the Population Register Center. The data on working ability were obtained from the Social Insurance Institution. Patients were divided into 3 groups: SCS trial only, SCS implanted permanently, and SCS implanted but later explanted. RESULTS A rehabilitation subsidy was given to 68 patients and 8 controls for a mean of 5.2 (95% confidence interval [CI] 2.4-8.2) and 0.2 (95% CI 0.05-0.6) days per month (P<.05). At the end of follow-up, 16 (37%), 13 (33%), 25 (22%), and 27 (5%) subjects were on disability pension (DP) in the SCS trial, SCS explanted, SCS permanent, and control groups. Patients in the SCS trial-only group were significantly more often on DP than were patients with permanent SCS (odds ratio 2.6; 95% CI 1.2-5.9; P=.02) CONCLUSION Permanent SCS usage was associated with reduced sick leave and DP. Prospective study will be required to assess possible predictive value.