Explantation Rates of High Frequency Spinal Cord Stimulation in Two Outpatient Clinics (vol 24, pg 507, 2021)

Objectives To report the explantation rates of high frequency 10 kHz spinal cord stimulation (SCS) in a real-world setting. Materials and methods This is a retrospective review of patients implanted with high frequency spinal cord stimulators over a 4-year period in two outpatient private practice clinics, from July 2015 through June 2019, using the Kaplan-Meier product-limit method to estimate probabilities of implant survival over time. Results The estimated median time to explantation was 3.5 years (95% confidence interval [CI] = 3.1-3.7) [Correction added on 15 October 2020, after first online publication: The preceeding sentence was amended to reflect the estimated median time.]. The estimated probabilities of implant survival beyond 1, 2, and 3 years postimplantation were 88.4% (95% CI = 81.3-93.0%), 76.5% (95% CI = 67.8-83.2%), and 60.7% (95% CI = 50.2-69.6%), respectively. The minimum (i.e., known) cumulative percentages of patients explanted by 1, 2, and 3 years postimplantation were 11.1% (14/126), 22.2% (28/126), and 32.5% (41/126), respectively. 65.9% of patients in this study had prior neurostimulation. Conclusions Recently, high frequency SCS technology has been demonstrated as more effective in treatment of lower- and leg-pain, compared to conventional low frequency SCS, in a 12-month randomized controlled trial (SENZA-RCT). Longer term results have yet to be published. In this study, we found that the explantation rate was much higher than expected, based on the prior studies demonstrating its efficacy. As the use of neuromodulation continues to grow, longitudinal data will be critical in understanding its long-term effects on treated patients.