Spinal cord stimulation—An important treatment against neuropathic pain

Torsten Gordh

doi:10.1016/j.sjpain.2014.05.004

Article Publicly Available

Spinal cord stimulation—An important treatment against neuropathic pain

Torsten Gordh

Published/Copyright: July 1, 2014

Published by

Become an author with De Gruyter Brill

Author Information Explore this Subject

From the journal Scandinavian Journal of Pain Volume 5 Issue 3

In this issue of Scandinavian Journal of Pain Kaare Meier, MD, PhD, presents a topical review, “Spinal cord stimulation: Background and clinical application” [1]. The review is based on the findings presented in Dr. Meier’s recent PhD dissertation, titled “Spinal cord stimulation: Clinical and experimental aspects” (University of Aarhus, Denmark, 2013). Usually the summaries of the PhD projects are not published in peer reviewed journals, and the results of the hard work behind a PhD degree are not reaching out to a larger sphere of colleagues. To give room for young researchers, Scandinavian Journal of Pain encourages the publication of topical reviews from PhD projects.

1 Neuropathic pain – some reflexions

Neuropathic pain is a common reason for chronic pain affecting about 1–5% of the population [2]. It causes very low quality of life [3]. Neuropathic pain can be the result of any lesion or disease that affects the peripheral or central nervous system. However, the great majority of patients subjected to nerve lesions do NOT develop neuropathic pain. Thus, nerve lesion is a necessary event, but not the only factor needed to cause neuropathic pain [4]. Probably genetic factors are involved, causing vulnerability in this respect [5,6]. The existing pharmacological treatments of neuropathic pain are often not successful [7], and there is a clear need to find better methods to relieve this troublesome condition

2 The role of spinal cord stimulation in the treatment of neuropathic pain

Electrical spinal cord stimulation (SCS), an invasive treatment used since 1965, is a pain relief technique that delivers a lowvoltage electrical current continuously to the spinal cord to block the sensation of pain. The method has gained increased use as an important and effective treatment against severe neuropathic pain of peripheral origin, and also against angina pectoris. The general opinion is that SCS is not effective in relieving central neuropathic pain states.

Kaare Meier gives an excellent review of the historical steps in the development of neurostimulation, starting with the first written account of electrical stimulation as pain treatment, where the Roman physician Scribonus Largus in year 46 AD describes the use of the electric torpedo ray fish against gout and headache, up to the publication of the “gate theory” in 1965. The first clinical tests of the SCS principle came about as a direct application of the ideas presented by Melzack and Wall – a truly fine example of translational research!

Today the annual number of implants performed is estimated to be around 50,000 worldwide. With correct indication and if implanted by an experienced implanter, success rates generally are in the range of about 50–75%. This is actually a very good outcome, since the patients usually have suffered from severe neuropathic pain, not possible to treat successfully with drugs. The lack of a clear definition for treatment success hampers evaluation of long-term treatment effect, and the reported success rate numbers depend on indication, experience of implanters, and the choice of success criteria. One problem in evaluating the pain relieving effects of SCS is that true double blind studies have been impossible to perform, due to the obvious paresthesia produced by the stimulation, when using the conventional stimulation pattern, normally in the 30–300 Hz range.

The complication rate is low. Most common complications to the treatment include electrode lead migration, lead breakage, infection, pain over the implant, and dural puncture.

It seems that SCS is effective in relieving symptoms of peripheral vascular disease and angina pectoris. An interesting effect of SCS treatment indicated by some clinical and experimental studies points to improvement in the ischaemic condition itself, thus acting as a disease modifying therapy.

3 Upcoming new treatment paradigms for neuromodulation

Recent developments include the use of high-frequency stimulation with frequencies in the kilohertz range. Interestingly, the patients cannot feel any paresthesia using the high frequency mode, which opens the possibility to carry out double blind studies. Also trials are underway with stimulation patterns relying on burst of impulses rather than a tonic stimulation pattern, and direct selective stimulation of the dorsal root ganglion with customized electrodes. Although the initial results seem promising, particularly in complicated cases, the effect of these new treatments need to be documented in larger studies.

4 The Aarhus Neuromodulation Database project

One of the problems in research in the field of neuromodulation, is that each centre usually has too few patients compared to the need to recruit the large well characterized patient cohorts required for high-powered outcome studies. In addition, many research centres have “their own” way to register classifications, outcomes and side effects. This leads to practical difficulties in research collaborations and in the possibility to compare results between different centres.

Dr. Meier has taken the important initiative to design and implement a comprehensive register for SCS treatment, named the Aarhus Neuromodulation Database [8]. The goal is that the database will offer a framework for a broad international collaboration, facilitating both improvements in patient care, as well as in international research relations. The construction allows expansion of the database to cover other types of treatments in the field of neuromodulation, such as peripheral nerve stimulation and all other new applications. It is constructed to allow adaptations to become compatible and flexible to the needs in different centres. It will be possible to join the Aarhus Neuromodulation Database by “open access” for other researchers in the world, at a no-cost basis.

This initiative represents a major contribution of benefit to the whole scientific community, worldwide, in the field of neuromodulation. It is a remarkable achievement by Dr. Meier and his group.

5 Conclusion

Spinal cord stimulation is according to a vast clinical experience an effective treatment against neuropathic pain. Today in the world there are many hundred thousands of patients treated with spinal cord stimulators, and they may show up anywhere in the health care system, anytime, also outside specialized pain clinics actually mastering the method. Many health care providers are probably not so familiar with the concept. This topical review by Kaare Meier may serve as a good introduction to the field of neuromodulation for neuropathic pain treatment.

DOI of refers to article: http://dx.doi.org/10.1016/j.sjpain.2014.03.001.

Conflict of interest: None.
Role of founding: No funding involved.

References

[1] Meier K. Spinal cord stimulation: background and clinical application. Scand J Pain 2014;5:175–81.Search in Google Scholar

[2] Bouhassira D, Lanteri-Minet M, Attal N, Laurent B, Touboul C. Prevalence of chronic pain with neuropathic characteristics in the general population. Pain 2008;136:380–7.Search in Google Scholar

[3] Meyer-Rosberg K, Kvarnstrom A, Kinnman E, Gordh T, Nordfors LO, Kristofferson A. Peripheral neuropathic pain – a multidimensional burden for patients. Eur J Pain 2001;5:379–89.Search in Google Scholar

[4] Linderoth G, Kehlet H, Aasvang EK, Werner MU. Neurophysiological characterization of persistent pain after laparoscopic inguinal hernia repair. Hernia 2011;15:521–9.Search in Google Scholar

[5] Denk F, McMahon SB, Tracey I. Pain vulnerability: a neurobiological perspective. Nat Neurosci 2014;17:192–200.Search in Google Scholar

[6] Dominguez CA, Kalliomäki M, Gunnarsson U, Moen A, Sandblom G, Kockum I, Lavant E, Olsson T, Nyberg F, Rygh LJ, Røe C, Gjerstad J, Gordh T, Piehl F. The DQB1 *03:02 HLA haplotype is associated with increased risk of chronic pain after inguinal hernia surgery and lumbar disc herniation. Pain 2013;154:427–33.Search in Google Scholar

[7] Dworkin RH, O’Connor AB, Backonja M, Farrar JT, Finnerup NB, Jensen TS, Kalso EA, Loeser JD, Miaskowski C, Nurmikko TJ, Portenoy RK, Rice AS, Stacey BR, Treede RD, Turk DC, Wallace MS. Pharmacologic management of neuropathic pain: evidence-based recommendations. Pain 2007;132:237–51.Search in Google Scholar

[8] Meier K, Nikolajsen L, Flink M, Simonsen R, Milidou I, Jensen TS, Sorensen JC. The Aarhus Neuromodulation Database. Neuromodulation 2012;16:506–13.Search in Google Scholar

Published Online: 2014-07-01

Published in Print: 2014-07-01

Articles in the same Issue

https://doi.org/10.1016/j.sjpain.2014.05.004