A small pilot study, published in the March issue of Neurosurgery, shows that a 16-contact spinal cord stimulation lead, in a multiplecolumn configuration, successfully relieves back pain in patients with failed back surgery syndrome
Philippe Rigoard, Department of Neurosurgery, Pain Management and Research Centre, Poitiers University School of Medicine, France, and colleagues wrote that a limitation of spinal cord stimulation is that it is less effective for the treatment of axial low back pain than it is for the treatment of radicular pain. They stated: “We must recognise that no conventional spinal cord stimulation technique could reliably and reproducibly cover a painful dorsolumbar region.” They added that, therefore, there has been a drive to develop spinal cord stimulation devices that cover a larger area and extend, steer, or focus the electrical field of stimulation within the spinal cord region.
In their study, Rigoard et al assessed whether a spinal cord stimulation lead using a three-column paddle of a 16-contacts (Specify 5-6-5, Medtronic) could provide bilateral paraesthesia coverage of the back with multipolar electrode configurations and which of 43 different configurations tested could reproducibly provide bilateral paraesthesia in the lumbar and/or dorsolumbar region in 11 patients with failed back surgery syndrome.
After six months, all patients said that they were, according to Rigoard et al, “satisfied with spinal cord stimulation and reported that they would undergo the same surgery again.” Also, all patients had significant reductions in their visual analogue scale scores and all improved in at least five categories of the Oswestry disability questionnaire.
For nine of the 11 patients studied, bilateral lumbar paraesthesia was achieved with at least one of the configurations evaluated and bilateral dorsolumbar paraesthesia was achieved with at least one of the configurations in seven patients. The success rate of multicolumn configurations was significantly higher than that of longitudinal configurations. Rigoard et al reported: “Nine of 11 patients obtained bilateral lumbar paraesthesia with at least one multicolumn configuration (p<0.05), whereas five patients of 11 felt bilateral lumbar paraesthesia with at least one monocolumn configuration (p<0.05).
Rigoard et al called their study “a valuable foundation for research”, and wrote that the focus of future studies should be on assessing the benefits of multicolumn configurations in patients with failed back surgery syndrome on a larger scale. They wrote: “In particular, future evaluations should attempt to demonstrate that these results are accompanied by significant clinical and functional benefits, notably in terms of the often serious medioeconomic repercussions of severe and refractory back pain.”