Introduction

Spinal Cord Stimulation (SCS) is an effective therapy for chronic neuropathic pain, with its long-term efficacy well-established. However, some patients experience loss of efficacy (LoE) over time and become refractory over the course of follow-up.¹ Providing various waveforms and programming options in novel SCS systems can facilitate more customized delivery of analgesic neurostimulation to chronic pain patients implanted with an SCS device. However, technologies that offer such optimization capabilities are not accessible to long-term implanted patients using older devices, some of whom may experience loss or attenuation in therapeutic efficacy over time. These patients therefore may elect to undergo a "conversion" to a different SCS system that possesses these capabilities.

Materials / Methods

This is a real-world, multicenter retrospective study of patients who were previously implanted with an SCS system (commercially-available device) who went on to convert to a new device (Boston Scientific SCS Systems, Boston Scientific, Valencia, CA, USA) capable of multiple modality stimulation and/or combination therapy via an applicable device adaptor and new implantable pulse generator (IPG). Pain relief and other associated outcomes using both the previously-implanted SCS system and the newly connected device IPG are being collected.

Results

Fifty-one patients (mean age = 57.1 years) have been assessed to date. A mean baseline overall pain (NRS) score of 7.7 ± 2.0 (n = 40) was reported prior to receiving SCS. Sixty nine percent of patients (N = 35) chose to convert for better pain relief followed by the need to access multiple programs (35%) and/or to get coverage of new areas of pain (31%). Previous SCS devices represent a range of different manufacturers. Among all patients (regardless of reasons for conversion), a pain score of 3.4 was noted at last follow up and sustained improvement was noted up to 3.2 years with current systems. In patients for whom the conversion was performed to “rescue” suboptimal outcomes with the previous system (N=47), a mean 3.5-point improvement with the current system was noted at last follow-up (3.1 years post-implant, 7.0 ⇒ 3.6, p<0.0001).

Discussion

When experiencing problems with SCS device longevity and/or loss of efficacy, some previously-implanted patients may be able to obtain better outcomes using more advanced neuromodulation systems that offer a range of waveforms and programming options to address their chronic pain.

Conclusions

Significant improvement was noted in overall pain in patients who converted to a new SCS device capable of providing multiple device programming options including anatomically guided paresthesia-based stimulation, combination therapy, and novel sub-perception modalities.

References

1. Deer TR, Mekhail N, Provenzano D, et al Neuromodulation Appropriateness Consensus Committee The appropriate use of neurostimulation avoidance and treatment of complications of neurostimulation therapies for the treatment of chronic pain Neuromodulation Appropriateness Consensus Committee Neuromodulation 2014 Aug 17 6 571-97. discussion 597-8.

2. Kumar K, Hunter G, Demeria D Spinal cord stimulation in treatment of chronic benign pain challenges in treatment planning and present status, a 22-year experience Neurosurgery 2006 Mar 58 3 481 96 discussion 481-96.

Learning Objectives

1. To assess pain relief outcomes (including long-term outcomes) in an SCS-implanted population (with sub-optimal pain relief) who have replaced their older generation SCS batteries with a newer generation device that provides multiple modalities.

2. To assess the reasons for conversion in patients who converted to newer SCS systems.

3. To evaluate the programs that are most preferred by patients who have converted to a newer SCS system.