Waveform-Conversion to Salvage Failed Spinal Cord Stimulation: A Systematic Review of Current Evidence

Area of Science:

• Neurology
• Pain Management
• Biomedical Engineering

Background:

• Spinal cord stimulation (SCS) is increasingly used for chronic pain management.
• Novel waveform technologies and expanded indications have driven SCS adoption.
• Loss of efficacy over time is a recognized challenge in SCS therapy.

Purpose of the Study:

• To review and describe the efficacy of salvage therapy in restoring analgesic benefit for SCS.
• To consolidate existing evidence on waveform switching as a salvage strategy.

Main Methods:

• A comprehensive literature search was conducted across PubMed, Web of Science, and Cochrane Library.
• 22 studies involving 1591 patients were included after full-text review and eligibility screening.
• Data extraction was performed by multiple reviewers to ensure accuracy.

Main Results:

• The primary indication for salvage therapy was loss of waveform efficacy or paresthesia coverage.
• Most patients received salvage therapy after experiencing efficacy loss with a single waveform.
• Salvage therapy demonstrated favorable efficacy, with 77.9% of trials reported as successful.

Conclusions:

• Waveform switching in SCS can restore analgesic benefits for some patients with refractory chronic pain.
• Long-term durability of salvage interventions, often involving device revision, requires further investigation.
• Prospective studies are necessary to refine patient selection, intervention timing, and long-term outcomes.