The effect of spinal cord stimulation on pain medication reduction in intractable spine and limb pain: a systematic review of randomized controlled trials and meta-analysis

Abstract

Objective: To synthesize the evidence regarding the effect of spinal cord stimulation (SCS) on opioid and pain medication reduction in patients with intractable spine or limb pain. Methods: A comprehensive literature search was conducted to identify RCTs of patients with chronic back and/or limb pain of greater than one year duration. Only comparative studies were included (ie, conventional SCS vs medical therapy, conventional SCS vs high-frequency SCS) and were required to have a minimum follow-up period of 3 months. Random effect meta-an alysis was used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% confidence intervals (CI). Results: We identified five trials enrolling 489 patients. Three of the trials reported the results as a number of patients who were able to reduce or eliminate opioid consumption in the SCS vs medical therapy group. The odds of reducing opioid consumption were significantly increased in the SCS group compared to medical therapy (OR 8.60, CI {1.93-38.30}). Two of the trials reported the results as mean medication dose reduction as measured by the Medication Quantification Scale (MQS) in the SCS group vs medical therapy group. MQS score significantly decreased in the SCS group and not in the medical group (WMD -1.97, 95% CI {-3.67, -0.27}). One trial reported a number of patients in high-frequency SCS who were able to reduce opioids vs number of patients in conventional SCS group who were able to reduce opioids. Thirty-four percent of the patients in the high-frequency group and 26% of the patients in the conventional SCS group were able to reduce opioid consumption; however, there was not a significant difference between groups (OR 1.43, 95% CI {0.74, 2.78}). This trial also quantified the opioid reduction in morphine equivalent dosage (MED). In the high-frequency SCS group, average MED decreased by 24.8 mg vs average MED decrease of 7.3 mg in the conventional SCS group. Again, the difference between groups did not reach statistical significance (-17.50, CI {-66.27, 31.27}). Conclusions: In patients with intractable spine/limb pain, SCS was associated with increased odds of reducing pain medication consumption. However, results should be treated with caution as available data were limited, and clinical significance of these findings requires further study.

Keywords: chronic back pain; chronic limb pain; high-frequency spinal stimulations; opioids; pain medications; painful diabetic neuropathy; spinal cord stimulation.

Figure 1

PRISMA Flow diagram.

Figure 2

Number of patients who decreased or eliminated pain medication who received conventional spinal cord stimulation with medical therapy vs medical therapy alone. Abbreviations: SCS, spinal cord stimulation; OR, odds ratio; CI, confidence interval.

Figure 3

Medication Quantification Scale (MQS) reduction in patients who received conventional spinal cord stimulation with medical therapy vs medical therapy alone. Abbreviations: SCS, spinal cord stimulation; WMD, weighted mean difference; CI, confidence interval.

Figure 4

Number of patients who reduced opioids in high-frequency spinal cord stimulation group vs number of patients who reduced opioids in conventional spinal cord stimulation group. Abbreviations: HF SCS, high-frequency spinal cord stimulation; OR, odds ratio; CI, confidence interval.

Figure 5

Average morphine equivalent dosing change in patients who received high-frequency spinal cord stimulation vs patients who received conventional spinal cord stimulation. Abbreviation: SCS, high-spinal cord stimulation.