Spinal cord stimulation: selection, trials, evidence, complications

Spinal cord stimulation has randomized evidence in refractory neuropathic pain such as diabetic neuropathy. Know the landmark trials, that a screening trial checks initial response but does not improve long-term outcome, and how to manage bleeding and infection risk.

1. Refractory painful diabetic neuropathy. In SENZA-PDN, 216 patients refractory to gabapentinoids and at least one other class were randomized; at 3 months, 79% with 10-kHz stimulation had at least 50% relief versus 5% with conventional management ¹.
2. Closed-loop stimulation uses ECAP feedback. Closed-loop systems measure the evoked compound action potential and adjust output in real time. In EVOKE, 77.6% versus 49.3% had at least 50% pain reduction at 36 months, closed-loop versus open-loop ².
3. The trial screens, it does not predict durability. Guidelines and regulators recommend trials to screen initial response before full implantation ³. Yet TRIAL-STIM found a screening-trial strategy did not improve pain at 6 or 36 months versus no trial ³.
4. Stimulator trials and implants are high bleeding risk. ASRA-led and ASIPP guidelines both rate them high risk because epidural hematoma can cause paralysis; apixaban holds are 3 days (ASRA) or 2 days (ASIPP), restarting about 24 hours afterward ⁴⁵.
5. Short DOAC holds do not need bridging. In the PAUSE cohort, stopping a DOAC without heparin bridging gave low bleeding and stroke rates ⁶.
6. Deep infection is an emergency. Fever, back pain and new deficits suggest epidural abscess: image promptly with MRI or CT, remove all hardware emergently, culture, admit and give broad-spectrum antibiotics ⁷.

Fever with worsening back pain or any new neurologic deficit after a stimulator procedure means deep infection or epidural abscess until proven otherwise; oral antibiotics suit superficial infection only ⁷.

• SENZA-PDN required HbA1c of 10% or less and BMI of 45 or less ¹.
• EVOKE kept blinding to the 36-month assessment ².
• Closed-loop output is adjusted every pulse to hold measured dorsal column activation within a target range ².
• TRIAL-STIM at 36 months: no difference in pain, quality of life, responder rate or explant rate ³.
• Guidelines and payers still require screening trials, despite TRIAL-STIM ³.
• Bleeding-risk classification for stimulators is high under both ASRA-led and ASIPP guidance ⁸⁵.
• DETER: deep device infection calls for complete hardware removal, cultures, admission and infectious disease input ⁷.
• In SENZA-PDN, the primary end point required 50% relief without worsening neurologic deficit ¹.

• Telling a patient a positive trial guarantees long-term success ³.
• Bridging a short apixaban hold with heparin ⁶.
• Treating a deep device infection with oral antibiotics and observation ⁷.
• Assuming open-loop and closed-loop stimulation perform the same long term; EVOKE favored closed-loop at 36 months ².