Predictors of Reduced Opioid Use With Spinal Cord Stimulation in Patients With Chronic Opioid Use

Objectives Spinal cord stimulation (SCS) has gained traction as an alternative to chronic opioid therapy in light of the opioid crisis. Prior reports vary widely in their estimates of its effect on opioid consumption. We therefore aimed to address the following questions: 1) Does chronic opioid use change after SCS? 2) Which patient characteristics predict reduced opioid consumption after SCS? Materials and Methods Claims from a private health insurance company were used to identify patients with SCS implantation from 2003 to 2014. We required 12 months of continuous data before and after surgery (i.e., a minimum total observation period of two years), and at least two opioid prescription fills in the six months before surgery. Daily morphine equivalent dose (MED) was calculated from prescription medication claims. Diagnosis codes identified common comorbidities. Results Hundred forty-five patients met inclusion criteria. MED of 65 was the most statistically meaningful preoperative dose threshold. Approximately half of patients decreased opioid use >20% after SCS implantation. Logistic regression analysis revealed age (p = 0.0362), gender (p = 0.0076), and preoperative daily MED < 65 (p = 0.0322) as predictors of meaningful reduction, which was defined as a 20% reduction in MED. Conclusions With only half of chronic opioid users demonstrating meaningful opioid reduction after SCS implantation, we demonstrate that current SCS technology does not reliably help a larger number of patients reduce opioid usage. Women, older age, and preoperative MED < 65 are predictive of meaningful opioid reduction but only one of these is modifiable. As not all patients saw benefit from their therapies, there is still much room for improvement in the treatment of refractory chronic pain that is associated with failed back surgery syndrome and chronic regional pain syndrome.