Are Spinal Cord Stimulators helpful for CRPS?

Spinal Cord Stimulation in CRPS: A Critical Appraisal of Limited Efficacy

Pradeep Chopra, MD, MHCM

Introduction

Complex Regional Pain Syndrome (CRPS) is a chronic pain condition marked by severe, disproportionate pain, autonomic dysfunction, and sensory-motor disturbances, often following trauma. Spinal cord stimulation (SCS) has long been offered as a treatment for refractory cases. While early studies suggested promise, more recent data and long-term follow-ups have cast doubt on the durability, consistency, and meaningfulness of its benefits in CRPS patients.

Questionable Efficacy Despite Initial Enthusiasm

Initial enthusiasm for SCS in CRPS came largely from short-term trials and industry-supported studies. The landmark Kemler et al. (2000) randomized controlled trial (RCT) suggested short-term pain relief at 6 months, but the 5-year follow-up (Kemler et al., 2008) revealed no significant difference in pain intensity or quality of life between SCS and control groups. Functional gains were minimal and temporary.

A more recent systematic review by Duarte et al. (2020) concluded that evidence for the effectiveness of SCS in CRPS is of low to very low certainty, primarily due to:

• Methodological flaws in the trials,
• High risk of bias,
• Small sample sizes, and
• Lack of sham controls or placebo comparisons.

The PLACEBO effect in neuromodulation remains a major confounder, especially since CRPS is known for central sensitization and affective pain components, which are responsive to placebo-related modulation of brain circuits.

Poor Long-Term Outcomes and Device Complications

Even in patients who report early relief, long-term outcomes are often disappointing:

• Explantation rates range from 10–30% within 5 years (Turner et al., 2010).
• Many patients experience loss of efficacy, often within 1–2 years.
• Device-related complications such as lead migration, infections, hardware failure, or need for revision surgeries are not uncommon.

Moreover, cost-effectiveness studies, such as by Taylor et al. (2010), suggest marginal utility in CRPS compared to other neuropathic pain indications, particularly when weighed against the high upfront costs of implantation and follow-up care.

Functional and Quality of Life Measures: Weak or Absent

Pain intensity scores, the most commonly reported outcome, do not necessarily correlate with functional improvementor quality of life (QoL)—two domains in which CRPS patients suffer profoundly. In most studies:

• Improvements in physical function, employment status, or mobility are minimal.
• Patients often continue to rely on medications, physical therapy, or assistive devices despite SCS implantation.

This is particularly problematic because CRPS is not merely a sensory disorder—it involves motor, autonomic, and inflammatory changes, which SCS does not reliably address.

Misalignment with CRPS Pathophysiology

CRPS is increasingly understood as a multifactorial, centrally mediated syndrome involving:

• Neuroinflammation,
• Autonomic dysregulation,
• Cortical reorganization, and
• Abnormal body perception.

SCS was designed for segmental nociceptive blockade and gate control theory, which may be insufficiently nuanced for this complex condition. The therapy assumes a static pain generator and fails to address maladaptive neuroplasticityor psychological comorbidities frequently seen in CRPS.

Ethical Concerns and Overuse

Despite these limitations, SCS continues to be widely promoted, often prior to exhausting conservative options or without adequate patient education. Invasive procedures with limited efficacy raise ethical concerns regarding:

• Informed consent (patients may not be told the full failure rate),
• Conflict of interest in device-sponsored studies,
• Irreversible anatomical alterations (e.g., scarring, lead fibrosis), and
• Psychological toll of failed interventions.

In vulnerable populations, particularly young patients with CRPS Type I, this can worsen pain catastrophizing, increase despair, and undermine trust in future care options.

Conclusion: Rethinking the Role of SCS in CRPS

While spinal cord stimulation may provide transient relief in carefully selected patients, the long-term efficacy remains questionable, and functional improvement is modest at best. Given the risks, costs, and inconsistent outcomes, SCS should not be considered a first-line treatment for CRPS and should only be offered within the context of multidisciplinary care and shared decision-making.

Future research must focus on:

• Better patient stratification,
• Sham-controlled trials,
• Alternative neuromodulation techniques (e.g., dorsal root ganglion stimulation), and
• Treatments targeting neuroinflammation and cortical changes.

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• Kemler, M. A., Barendse, G. A., van Kleef, M., de Vet, H. C., Rijks, C. P., Furnée, C. A., & van den Wildenberg, F. A. (2000). Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy. New England Journal of Medicine, 343(9), 618–624.
• Kemler, M. A., de Vet, H. C., Barendse, G. A., van den Wildenberg, F. A., & van Kleef, M. (2008). Effect of spinal cord stimulation for chronic complex regional pain syndrome Type I: five-year final follow-up of patients in a randomized controlled trial. Journal of Neurosurgery, 108(2), 292–298.
• Duarte, R. V., Nevitt, S., McNicol, E., Taylor, R. S., & Eldabe, S. (2020). Systematic review and meta-analysis of placebo/sham controlled trials of spinal cord stimulation for neuropathic pain. PAIN, 161(1), 24–35.
• Turner, J. A., Loeser, J. D., Deyo, R. A., & Sanders, S. B. (2010). Spinal cord stimulation for patients with failed back surgery syndrome or complex regional pain syndrome: a systematic review of effectiveness and complications. Pain, 108(1), 137–147.
• Taylor, R. S., Taylor, R. J., Van Buyten, J. P., & Buchser, E. (2010). Cost-effectiveness of spinal cord stimulation for chronic pain. Neuromodulation: Technology at the Neural Interface, 13(4), 253–262.

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