Dorsal root ganglion identified as a promising target for neuromodulation

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At the 18th annual North American Neuromodulation Society (NANS) congress, researchers presented 20 international, peer-reviewed scientific abstracts from Australia and Europe highlighting clinical results of the Axium neurostimulator system (Spinal Modulation) for the treatment of chronic, intractable pain by targeting the dorsal root ganglion.

Chronic post-surgical pain

Two single-centre, retrospective reviews from Australia and an international retrospective case review demonstrated improvement in pain scores and reduced disability in patients suffering from chronic post-surgical pain. Highlights include:

  • A long-term single-centre study of 29 patients implanted with the Axium neurostimulator system reported 66% pain reduction at 12 months. The Oswestry Disability Index (ODI) decreased from 43.7 at baseline to 25.6 at 12 months, a 41% improvement.
  • A single-centre review of 16 patients with chronic post-surgical pain affecting different anatomies presented 77.2% pain relief at six months.
  • A multi-centre review of 13 patients with intractable knee pain after surgery reported average pain relief of 71.2% (mean follow-up of 6 months).

Upper limb neuropathy

Prospective data pooled from four European studies reported pain relief and improved quality of life for 16 patients with upper limb neuropathies including complex regional pain syndrome, post-amputation pain, peripheral nerve injury, and post-surgical radicular pain. Highlights include:

  • Median visual analogue scale (VAS) at baseline and six months were 82 and 30, respectively, a 52.7% improvement.
  • Mean EQ-5D index scores showed improvement in quality of life, increasing from 0.252 at baseline to 0.757 at six months.
  • Subjects did not experience changes in paraesthesia with body position changes.

Visceral pain

A retrospective observational study presented early positive outcomes for nine patients treated for abdominal visceral pain. Highlights include:

  • Average VAS reduction of 34.4mm (mean follow up of 9.7 months).
  • Mean EQ-5D index score improved from 0.004 to 0.569 after treatment.
  • The EQ-5D health status improved from 36.6 to 67.7.
  • The most noticeable changes in EQ-5D profiles were in pain and depression/anxiety levels.
  • Average reduction in opioid usage at last follow-up was 147.7mg or 62.1%. Three out of the seven patients that were on morphine pre-treatment completely stopped their intake.

“The data shows that this targeted form of spinal cord stimulation may be a promising treatment option for multiple chronic pain conditions that can be hard to treat with conventional spinal cord stimulation,” says Bruce Mitchell, of Metro Pain Group in Australia, and one of the researchers at NANS. “In particular for post–surgical chronic pain, which represents a large patient population group that is otherwise underserved, the technique shows great promise.”

All research topics highlighted above are from use of the Axium neurostimulator system in Europe and Australia. In the USA, the Axium neurostimulator system is restricted to IDE investigational use.