SCS Stimulation Clamp to Assess Impact of Stimulation on Glucose Metabolism

Study Overview
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Brief Summary
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In 1967 spinal cord stimulation (SCS) for the treatment of chronic neuropathic pain was established. Today various pain syndromes like the failed back surgery syndrome (FBSS), the complex regional pain syndrome (CRPS), ischemic pain or phantom limb pain are treated with SCS. The development of this technique based on the so called Gate Control Theory which states that stimulation of the mechanosensitive Aβ fibers suppresses the transmission of pain stimuli via the pain-sensitive C fibers to the brain in the spinal cord. Conventional SCS consists of periodically emitted tonic stimuli with a frequency between 30 and 120 Hz. During implantation, the electrodes are placed in the epidural space in such a way that the paraesthesia caused by nerve stimulation covers the painful area (dermatome), thus relieving the pain. In 2010 de Ridder et al. published an article presenting the so called Burst Stimulation where series of high-frequency impulses are released at defined time intervals (frequency: 40 Hz with peaks of 500 Hz per volley). Compared to the tonic SCS the burst technique is more effective and in most cases no paraesthesia is reported. However, potential effects of SCS stimulation on other organ systems have only been insufficiently examined.Especially possible effects of SCS on the glucose metabolism has not been investigated so far. However, it is important to investigate a possible effect for two reasons: SCS could cause severe hypoglycemia which must be avoided. Furthermore, if SCS affects blood sugar levels, it is also of interest what mechanisms are involved and how this knowledge can be used to control elevated blood glucose levels. The present study is a pilot. The investigators want to examine possible effects of SCS therapy on blood glucose metabolism. Therefore hyperinsulinemic euglycemic clamps with an insulin infusion of 1mU / kg body weight per minute are performed. During the clamp the investigators apply different SCS techniques in a randomly order. Insulinsensitivity is determined at different time points.

Official Title
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Effects of Burst and Tonic Spinal Cord Stimulation (SCS) in Chronic Neuropathic Pain on Blood Glucose Levels

Conditions
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Spinal Cord Stimulation (SCS), Blood Glucose Metabolism, Euglycemic Hyperinsulinemic Clamp

Intervention / Treatment
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* Device: Sham SCS stimulation
* Device: Tonic SCS stimulation
* Device: Burst SCS Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Understand and voluntarily sign an informed consent document prior to any study related assessments/procedures. HbA1c < 6,0% state after implantation of an neuromodulation device Clinical routine blood parameters within the normal ranges Exclusion Criteria: diabetes mellitus Acute diseases such as infections (e.g.) within the last four weeks Hb < 13 g/dl anamnestic heparin-induced thrombocytopenia any neurologic or psychiatric disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham SCS stimulation<br>Sham SCS stimulation via implanted neuromodulation device | Device: Sham SCS stimulation<br>* Sham SCS stimulation via implanted neuromodulation device for 45 min during the steady state of a hyperinsulinemic euglycemic clamp.<br>|
| Active Comparator: Tonic SCS stimulation<br>Tonic SCS stimulation via implanted neuromodulation device | Device: Tonic SCS stimulation<br>* Tonic SCS stimulation via implanted neuromodulation device for 45 min during the steady state of a hyperinsulinemic euglycemic clamp.<br>|
| Active Comparator: Burst SCS Stimulation<br>Burst SCS stimulation via implanted neuromodulation device | Device: Burst SCS Stimulation<br>* Burst SCS stimulation via implanted neuromodulation device for 45 min during the steady state of a hyperinsulinemic euglycemic clamp.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in peripheral insulin sensitivity (tonic/burst versus sham stimulation) | Effect of tonic or burst versus sham SCS stimulation on insulin sensitivity assessed by hyperinsulinemic euglycemic clamp. | 130-150 minutes, 190-210 minutes and 250-270 minutes respectively during euglycemic clamp | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in peripheral insulin sensitivity (tonic versus burst stimulation) | Differential effects of tonic versus burst SCS stimulation on insulin sensitivity assessed by hyperinsulinemic euglycemic clamp. | 130-150 minutes, 190-210 minutes and 250-270 minutes respectively during euglycemic clamp |