Current Evidence on Use of Spinal Cord Stimulation for Painful Diabetic Peripheral Neuropathy
Spinal cord stimulators (SCS) have been used in clinical practice for the treatment of chronic neuropathic pain for over 40 years. The mechanisms by which SCS produces pain relief in neuropathic pain are still yet to be fully understood. Increasing efforts have been made on the part of researchers to fully elucidate these mechanisms of action. One of the most important ways to generate new knowledge in this field is through the painstaking discipline of conducting well-designed clinical and basic science research.
Evidence for Effectiveness
The most compelling evidence for the effectiveness of SCS in the treatment of chronic pain has been with failed back surgery syndrome.1,2 Since the work by Tesfaye et al in 1996 demonstrating the effectiveness of SCS in painful diabetic peripheral neuropathy (PDPN) researchers have been working to establish these findings unequivocally through randomized controlled multicenter trials.3-5 The recent findings by Slangen et al reported in Diabetes Care represent one of such important efforts.6
The study by Slangen et al confirms previous findings that SCS provides >50% pain relief in 60% to 70% of well-selected patients for the initial SCS trial. In addition, the study confirms benefit with variation in day and nighttime pain as well as a reduction in peak pain scores.6 This is important given that few studies have examined the benefit of various treatment modalities, including SCS with nighttime pain, which is reported to be most severe by patients with PDPN.
Pluijms et al5,7 have investigated how best to select patients based on special pain testing known as quantitative sensory testing, which provides some objective evidence of how treatments like SCS affect how a person’s nervous system processes pain. The response to such a test may help select patients who are more likely to respond well to SCS treatment. A possible extension to this work would be to determine if using SCS much earlier in the disease process may actually help modify progression of PDPN, given the ability to modify not only the pain pathways but also the sympathetic nervous system (neuroendocrine effect) and peripheral vascular reactivity. A review by Prager provides a comprehensive overview of the suggested mechanisms of action of SCS in complex regional pain syndrome (CRPS), and this may by extension apply to PDPN.8
In spite of the complication reported in the study by Slangen et al (ie, a dural puncture that led to subdural hematoma and death), SCS is associated with a relatively low major complication rate. Mekhail et al in 2011 reported their experience with 707 consecutive patients treated with SCS and found that lead migration was common (22.6%) and that implantation-related infections were more common among patients with diabetes than in the non-diabetic population (9% vs. 4%, respectively).9
In summary, this study by Slangen et al is part of an important process of evaluating the value of SCS in the treatment of PDPN. Spinal cord stimulation remains a highly under-utilized treatment modality, which has the potential to provide consistent pain control over time in well selected patients. More work is required to provide unequivocal evidence for clinical benefit, optimum timing for use, and elucidating the exact mechanism of action of the device.
November 17, 2014