The aim of this prospective study was to investigate whether spinal cord stimulation (SCS) significantly reduces pain intensity for up to 18-month follow-up in patients with chronic neuropathic pain. Forty-eight patients were recruited. Patients rated their pain using a Visual analog scale (VAS) and pain-related disability using the Oswestry Disability Index (ODI) at baseline (1 week prior to SCS surgery) and at 6-, 12-, and 18-month follow-up. Pain intensity significantly decreased from baseline to all 3 time points [F (3,135) = 16.264, p <0.001]. The greatest difference in the reduction of pain intensity was observed between baseline (M = 7.20, SD = 1.34) and 6-month follow-up (M = 4.60, SD = 2.20), [t(47) = 6.741, p <0.001]. However, when looking at differences between the 6-month follow-up and subsequent assessments, statistically significant increases in pain intensity from the 6-month to the 12-month follow-up [t(47) = −2.788, p = 0.008], and from the 6-month to the 18-month follow-up [t(47) = −3.339, p = 0.002] could be observed. Statistically significant changes were also observed for clinical changes in pain scores [F (2,94) = 4.972, p = 0.009. There was a significant decrease in the percentage of clinical change obtained from the 6-month (M = 33.19, SD = 35.63) to the 12-month follow-up (M = 23.76, SD = 33.62), [t(47) = 2.347, p = 0.025], and from the 6-month to the 18-month follow-up (M = 18.34, SD = 33.51), [t(47) = 3.072, p = 0.004]. A number of patients also reported higher levels of pain intensity at the 12-and 18-month follow-up than at baseline. Pain-related disability scores significantly decreased from baseline (M = 55.04, SD = 16.43) to the 6-month follow up (M = 46.98, SD = 19.05), [t(47) = 3.464, p = 0.001] and from baseline to the 12-month follow up (M = 48.49, SD = 20.94), [t(47) = 2.918, p = 0.005], but not during the 18-month follow up (M = 51.75, SD = 20.92), [t(47) = 1.330, p = .190]. There was a significant increase in pain-related disability between the 6- and the 18-month follow up [t(47) = −2.188. p = 0.034]. These findings suggest that the beneficial effect of SCS on pain intensity may diminish over time, and that the 6-month follow-up scores may reflect a placebo effect. Publisher statement: This is an Accepted Manuscript of an article published by Taylor & Francis in the British Journal of Neurosurgery on 18th June 2015, available online: http://www.tandfonline.com/doi/full/10.3109/02688697.2015.1054352 .
Bibliographical noteDue to publisher policy, the full text will not be available on the repository until the 18th of June 2016.
This is an Accepted Manuscript of an article published by Taylor & Francis in the British Journal of Neurosurgery on 18th June 2015, available online: http://www.tandfonline.com/doi/full/10.3109/02688697.2015.1054352 .
- chronic pain
- clinical efficacy
- neuropathic pain
- spinal cord stimulation