Alternate Intraspinal Targets for Spinal Cord Stimulation: A Systematic Review.

BACKGROUND: Conventional dorsal column spinal cord stimulation (SCS) provides less than optimal pain relief for certain pain syndromes and anatomic pain distributions. Practitioners have sought to treat these challenging therapeutic areas with stimulation of alternate intraspinal targets.

OBJECTIVE: To identify and systematically review the evidence for the value neuromodulating specific neuronal targets within the spinal canal to achieve relief of chronic pain.

METHODS: A systematic literature search was conducted using PubMed for clinical trials published from 1966 to March 1, 2015 to identify neurostimulation studies that employed non-dorsal column intraspinal stimulation to achieve pain relief. Identified studies on such targeted intraspinal stimulation were reviewed and graded using Evidence Based Interventional Pain Medicine criteria.

RESULTS: We found a total of 13 articles that satisfied our search criteria on targeted, non-dorsal column intraspinal stimulation for pain. We identified five studies on neurostimulation of the cervicomedullary junction, six studies on neurostimulation of the dorsal root ganglion, two studies on the neurostimulation of the conus medullaris, unfortunately none was found on intraspinal nerve root stimulation.

LIMITATIONS: The limitations of this review include the relative paucity of well-designed prospective studies on targeted SCS.

CONCLUSIONS: Clinical use of intraspinal neurostimulation is expanding at a very fast pace. Intraspinal stimulation of non-dorsal column targets may well be the future of neurostimulation as it provides new clinically significant neuromodulation of specific therapeutic targets that are not well or not easily addressed with conventional dorsal column SCS. In addition, they may avoid undesired stimulation induced paraesthesia, particularly in non-painful areas of the body.