Long Term Pain Reduction and Explantation Rates of Spinal Cord Stimulation: A Systematic Review and Meta-Analysis

Area of Science:

• Neuromodulation
• Pain Management
• Medical Device Outcomes

Background:

• Spinal Cord Stimulation (SCS) treats chronic pain conditions like persistent spinal pain syndrome, complex regional pain syndrome, painful diabetic peripheral neuropathy, and radiculopathy.
• SCS treatment involves a trial phase before permanent implantation, with trial failure and long-term outcomes being key considerations.

Purpose of the Study:

• To quantify three critical SCS outcomes: trial phase nonresponse, annual explantation rates post-implantation (up to three years), and annual rates of <50% pain reduction among patients with retained implants (up to three years).

Main Methods:

• A systematic literature review of PubMed, Embase, and Cochrane databases identified studies with quantitative SCS outcome data.
• Data were extracted and summarized, with pooled rates calculated using a three-level binomial generalized linear mixed model.
• Risk of bias and certainty of evidence were assessed using established frameworks (Risk of Bias 2, NIH tools, GRADE).

Main Results:

• The analysis included 38 studies. The pooled trial phase failure rate was 16.2%.
• Pooled annual explantation rates were 4.0% (1 year), 7.0% (2 years), and 11.9% (3 years).
• Pooled annual rates of <50% pain reduction were 24.2% (1 year), 27.0% (2 years), and 32.8% (3 years).

Conclusions:

• 16.2% of patients did not proceed past the SCS trial phase.
• At three years post-implantation, an average of 44.7% of patients with permanent implants had undergone explantation or reported <50% pain relief.
• Outcomes were aggregated without stratification by influencing factors like waveform.