Spinal Cord Stimulation for Refractory Pain in Erythromelalgia

Study Overview
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Brief Summary
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Erythromelalgia is a rare disorder characterized by red, warm, and painful extremities, which is often precipitated by warm conditions. The pathophysiology is incompletely understood. The management of pain in erythromelalgia is challenging as no single therapy has been found to be effective. Response to pharmacotherapy varies, meaning that the physician has to take a stepwise trial and error approach with each patient. Consequently, this disorder is often associated with poorer health-related quality of life. There is currently no consensus or guideline on management of pain in erythromelalgia. Spinal cord stimulation is a widely applied therapy to treat severe chronic pain of various origin. Case reports and anecdotal evidence suggest that this therapy might alleviate refractory pain in patients with erythromelalgia. The aim of this trial is to evaluate the efficacy of spinal cord stimulation for refractory pain in erythromelalgia.

Official Title
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Spinal Cord Stimulation for Refractory Pain in Erythromelalgia

Conditions
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Erythromelalgia

Intervention / Treatment
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* Procedure: Burst Spinal Cord Stimulation
* Procedure: Sham spinal cord stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A diagnosis of primary or idiopathic erythromelalgia Patients ≥18 years who have developed chronic pain that has remained refractory to medical treatment for ≥6 months. Minimum pain intensity of 5/10 on a numeric rating scale NRS at baseline. Successful two-week SCS testing period with tonic stimulation (≥2 points reduction in pain NRS from baseline). This means patients will experience paresthesia during the trial period of spinal cord stimulation. Exclusion Criteria: Coexisting conditions that would increase procedural risk (e.g., sepsis, coagulopathy). History of laminectomy or posterior fusion at the thoracolumbar junction, where percutaneous electrode end tips are routinely placed. Abnormal pain behavior and/or unresolved psychiatric illness. Unresolved issues of secondary gain or inappropriate medication use. Unfit for participation for any other reason as judged by the study physician.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: During 6 months following implantation of a pulse generator, all patients will undergo 4 six-week long periods with either burst spinal cord stimulation (SCS) or no stimulation (sham) in a randomized order. During this period all patients will undergo two periods of SCS and sham stimulation.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Burst spinal cord stimulation (SCS)<br>following implantation of a generator that sends pulses to a thin wire (lead), which delivers pulses to nerves along the spinal cord, the patients will initially undergo four six-week long periods with either burst SCS or no stimulation (sham) in a randomized order. During this period all patients will undergo two periods of SCS and sham stimulation. | Procedure: Burst Spinal Cord Stimulation<br>* Burst stimulation utilizes complex programming to deliver high-frequency stimuli of a 40 Hz burst mode with 5 spikes at 500 Hz per spike delivered in a constant current mode<br>Procedure: Sham spinal cord stimulation<br>* A pulse generator is implanted, but no spinal cord stimulation is provided<br>|
| Sham Comparator: sham spinal cord stimulation (SCS)<br>following implantation of a generator that sends pulses to a thin wire (lead), which delivers pulses to nerves along the spinal cord, the patients will initially undergo four six-week long periods with either burst SCS or no stimulation (sham) in a randomized order. During this period all patients will undergo two periods of SCS and sham stimulation. | Procedure: Burst Spinal Cord Stimulation<br>* Burst stimulation utilizes complex programming to deliver high-frequency stimuli of a 40 Hz burst mode with 5 spikes at 500 Hz per spike delivered in a constant current mode<br>Procedure: Sham spinal cord stimulation<br>* A pulse generator is implanted, but no spinal cord stimulation is provided<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in pain | assessed with a 0 -to-10 numerical rating scale (NRS) | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in generic health-related quality of life | Assessed with the Euro-Qol-5D (5L) | 6 months | 
| Oswestry disability index (ODI) score | questionnaire originally designed to quantify disability for degenerative conditions of the lumbar spine, possibly a relevant outcome measure also in patients with erythromelalgia as it covers intensity of pain, ability to care for oneself, ability to walk, ability to sit, ability to lift, sexual function, ability to stand, social life, sleep quality, and ability to travel. The index is scored from 0 to 100. Zero means no disability and 100 reflects maximum disability. | 6 months | 
| Daily physical activity | measured by use of a body-worn accelerometer (activPALs from PAL Technologies Ltd., Glasgow, United Kingdom) attached by a waterproof tape to the midpoint of the patients' anterior right thigh | 6 months | 
| Severity of erythema | assessed using the Patient's Self-Assessment (PSA) scale | 6 months | 
| Health Care Provider's Costs | Cost-effectiveness (cost per gained quality-adjusted life year) | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Spinal Cord Stimulation