Spinal cord stimulation relieved pain and improved sensation in diabetic neuropathy

Design

Multicentre randomised controlled trial, open-label with blinded sensory assessment

Population

91 adults with painful diabetic neuropathy

Primary outcome

At least 50% lower-limb pain relief

Effect

27 of 34 with stimulation vs 2 of 50 with medical management alone (P < 0.001)

PDN-Sensory randomised 91 people with painful diabetic neuropathy to conventional medical management alone or 10-kHz spinal cord stimulation added to it. Sensory scores and skin-biopsy nerve fibre density were assessed by staff blind to allocation.

In a worst-case modified intention-to-treat analysis, 27 of the 34 stimulation patients who went on to a temporary trial reached at least 50% lower-limb pain relief, against 2 of 50 on medical management. At six months, 55% versus 25% had a meaningful improvement on the modified Toronto Clinical Neuropathy Score, and calf nerve fibre density rose slightly with stimulation while it fell marginally without it. Eight of ten secondary end points, including sleep and quality of life, were met.

Pain relief from this device has been shown before; the blinded sensory and nerve-fibre signals are the new part, and the authors raise the possibility of disease modification. That needs longer follow-up and replication before anyone tells patients nerves are regrowing.

The device is invasive, costly and patients were not blinded to pain outcomes. It is a referral option for refractory pain, not a step after one failed drug.

• Consider pain-service referral for spinal cord stimulation when neuropathic pain persists despite adequate trials of first-line agents.
• Document a baseline sensory examination and pain score so any later change can be judged.
• Keep foot protection and screening unchanged — better pain control does not mean protective sensation has returned.
• Discuss that the device requires surgery, a temporary trial and ongoing follow-up before it becomes permanent.

Why it matters

It moves stimulation from a pain-only treatment towards something that may also affect the nerve itself — a question worth watching.

Don't overread it

Six months of nerve-fibre data cannot establish that the device modifies the disease.

The statistics, in plain English

The pain result is large: about four in five implanted patients responded against one in 25 on medication alone. The sensory and nerve-fibre findings are smaller and come from those with six-month data, so they are more open to chance and to drop-out effects than the headline pain result.

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