Spinal cord stimulation and chronic pain: In the end it’s about the patient

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Krishnan Chakravarthy

Krishnan Chakravarthy writes in NeuroNews about how spinal cord stimulation can be used to treat chronic pain and how this can help America overcome its opioid epidemic.

The statistics are clear, we are amid an opioid epidemic that requires a deeper reflection into what we do at the personal, professional, and public level as pain practitioners from every field including primary care. As the epidemic continues to spiral out of control, the emphasis on opioid sparing strategy through use of novel technology has become a major impetus for pain management doctors worldwide. We can no longer debate the long-term detrimental effects of chronic opioid use in the absence of strong medical thought process and good sound reasoning for specific indications where opioid use may still have a role. We must make sensible diagnostic decisions and prevent erratic swings in the pendulum of opioid prescriptions. We, as physicians must take responsibility and provide outstanding evidence-based care. But to do so requires expanding our tool box and to offer patients a reasonable alternative to deal with their crippling chronic pain. That solution may lie in neuromodulation technology. The last 20 years has seen an explosion of new technology that is rapidly advancing the care of chronic pain patients through stimulation of the spinal cord or peripheral nerves through localised current. But with growing promise of any new game changing technology comes more pressing questions on its use, future, and where we see its role in the growing opioid sparing treatment algorithm.

How do we as patients and physicians make sense of the information that is out there? If one were to simply scan through a Google search for spinal cord stimulation we would find search hits that would have words such as “tonic, burst, high-frequency, dorsal root ganglion, paresthesia, paresthesia-free, closed-loop,” attached to the word stimulation and companies such as Abbott, Nevro, Boston Scientific, Medtronic, and more. In a dizzying pace that is seeing a growing market and more novel corporate neuromodulation players, we as physicians ourselves find a certain sense of confusion on how we determine the appropriate diagnostic algorithm, and what device to use. The certain familiarity that comes with relationships with device representatives that provide outstanding care to our patients and device companies who provide unforeseen value seen in our practices makes a large portion of our decision tree on which device we use. But the reality is that a myriad of data fills a rapidly expanding field with small sample sizes, unknown mechanisms of action, and a shortage of well controlled randomised controlled trials.

As physician researchers we all have the ultimate goal in mind to help patients by creating studies with good methodology and well-defined end points. However, we are limited to data points that are subjective in nature which lends to the complexity of studying and treating chronic pain. We are at a critical inflection point for a technology that can have a tremendous value. We must be critical of the evidence and we must learn to embrace a very important point that every patient is an individual with a complexity of cultural, societal, and personal experiences that has shaped his response to chronic pain. Sir Williams Osler, who has been often regarded as the father of modern medicine says beautifully, “The good physician treats the disease; the great physician treats the patient who has the disease.” I recall just recently speaking with a patient from South Asia who had just undergone an anterior cervical disectomy fusion surgery and was able to manage his post-operative pain on Tylenol. Or the veteran population where the complexity of psychiatric issues play a major role in determining their pain management. We must put changes in visual analogue scale (VAS) scores into the clinical context, into the history and physical, and place less emphasis on subjective data points and more on ancillary data such as mobility, functionality and the individual patient and what they actually tell us in clinic visits post neurostimulation treatment.

In an area of medicine specific to neuromodulation that is driven by endpoints of pain reduction with still largely unknown mechanisms of action there must be a call to emphasise clinical relevance. In a rapidly expanding digital age that is shaping our culture, so too will the concept of personalised medicine provide a guiding direction to neuromodulation therapy. How do physicians and patients adopt this approach to neuromodulation therapy that has been very successful in the field of oncology? More emphasis must be placed on detailed history and physical, with emphasis on past history, family history, and social factors. There is growing evidence that BURST stimulation wave pattern affects the affective component pathway and has been suggested to not only improve pain but has been postulated to be an effective method to improve mood and depression. If this is the case then a patient’s prior psychological history will be important in making decisions on whether to choose tonic or burst waveform. There is also an abundance of evidence that suggests that the dorsal root ganglion is critical in mitigating systemic inflammatory responses, one could envision use of DRG stimulation with specific dermatomal pain in combination with inflammatory co-morbidities. Furthermore, preferences are clear that patients would choose to have high frequency over traditional stimulation so that they do not experience the “paresthestic or buzzing” effect.

But we can take this one step further, and begin looking at the process of ancillary measures, that can go from a macroscopic level based on detailed questionnaires that assess functionality, sleep, depression, PTSD, to more specific physiological data points such as heart rate, blood pressure, blood and genetic biomarkers, and real time fMRI, MEG, to EEG imaging. Certainly, one can suggest that this is easier said than done from the perspective of increasing commercial pressures to keep pain practices open. However, unless we standardise our outcome measurements and technical approaches using standard treatment algorithms, we will suffer the same consequences of variable findings with studies that suggest no differences in waveforms, to claims of superiority of therapy with no clinical relevance. A therapy that is dependent on insurance reimbursement, increasing emphasis on implementation of best practices guidelines are critical to the longevity of this therapy. We must base our choices not simply on anecdotal evidence but must be disciplined to encourage discussion based on evidence and medical reasoning to suggest why we choose one stimulation modality versus another. We must encourage new industry entrants into the field to be critical of their technology and must hold strict adherence to clinical relevance and emphasis on randomised well controlled studies supporting their therapy.

If we do not take these steps and create more stringent standards with increasing emphasis on structured treatment algorithms with a focus on personalised tailored therapy, we not only risk the long-term sustainability of our therapy but we risk providing sub-standard care to our patients. We have an incredible opportunity with neuromodulation therapy. The therapy has changed the course of countless lives crippled by chronic pain and has proven to be and will be extremely important as we deal with the growing opioid epidemic. Let us take this chance to make important policy, and personalised clinical decision making to support this therapy by tailoring it to individual patients. Let us expand the measured subjective and objective data points, and place greater emphasis on educating the patient and medical community on the tremendous potential of this technology in the context of tailored individualised therapy.

Krishnan Chakravarthy assistant clinical professor at University of California San Diego, USA, who specialises in multi-modal pain management

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