Spinal cord stimulators: socioeconomic disparities in four US states

Spinal cord stimulators (SCS) are increasingly placed in the United States in both the inpatient and outpatient setting. Although these interventions appear to be safe, the characteristics of the patients selected for ambulatory procedures have not been investigated.

We performed a retrospective cohort study involving 4843 patients who underwent outpatient and 4197 who underwent inpatient SCS placements and were registered in State Ambulatory Surgery Databases and State Inpatient Databases, respectively, for New York, California, Florida, and North Carolina from 2005 to 2008.

In a multivariate analysis, male gender (odds ratio (OR) 1.22, 95% confidence interval (CI), 1.12, 1.33), high volume hospitals (OR 2.16, 95% CI, 1.94, 2.41), and Caucasian race (OR 1.25, 95% CI, 1.10, 1.41) were significantly associated with outpatient procedures. Higher Charlson Comorbidity Index (OR 0.36, 95% CI, 0.24, 0.54) and Medicare/Medicaid insurance (OR 0.75, 95% CI, 0.67, 0.83) were associated with a decreased chance of outpatient procedures. The rate of 30-day postoperative readmissions was higher among inpatients. Institutional charges were significantly lower for outpatient lumbar discectomies. The median total charge for inpatient hospitalization after SCS placement was $60,624 as compared with $22,288 for the outpatient setting (p < 0.0001).

Access to ambulatory SCS placement appears to be more common for Caucasians, male patients, with private insurance, and fewer comorbidities, in the setting of higher volume hospitals. Further investigation is needed in the direction of mapping these disparities for appropriate resource utilization.