Quantitative Assessment of Painful Diabetic Peripheral Neuropathy After High Frequency Spinal Cord Stimulation

Not Applicable

Completed

Conditions: Painful Diabetic Neuropathy

Interventions: Device: High Frequency Spinal Cord Stimulator

Registration Number: NCT03769675

Lead Sponsor: Mayo Clinic

Brief Summary: Will participants with painful lower extremity diabetic peripheral neuropathy (DPN) that are treated with high frequency spinal cord stimulation (HF10 SCS) have improvements in lower extremity peripheral nerve function?

Detailed Description: This research study is being conducted to find out if spinal cord stimulation (SCS) can improve nerve function. SCS is FDA approved for the treatment of intractable neuropathic (nerve) pain related to diabetic peripheral neuropathy. With SCS a wire is placed in the epidural space and the spinal cord is stimulated to interrupt the pain signal coming from the legs. The spinal cord stimulator is a device similar to a pacemaker (which helps treat abnormal rhythms of the heart). Recent studies have suggested that SCS with high frequencies can improve nerve function for subjects with painful peripheral neuropathy therefore, the investigators are looking to measure changes in nerve function after SCS for treatment of painful diabetic peripheral neuropathy.

The purpose of this research is to gather information on the effect of high frequency spinal cord stimulation (HF10) on nerve function with a spinal cord stimulator.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 10

Inclusion Criteria

Type 2 diabetes mellitus
Refractory predominantly lower extremity neuropathic pain for > 1 year
Presence of length dependent peripheral neuropathy on sudomotor testing
Completed spinal cord stimulation trial with 40% or greater pain reduction from baseline
Failed medication trials or contraindication to gabapentin medications (gabapentin, pregabalin) and/or serotonin/norepinephrine reuptake inhibitors (tricyclic antidepressant (TCA) or duloxetine or venlafaxine)
Average pain score on a visual analog scale (VAS) of ≥ 5 (with 0 representing no pain and 10 the worst pain imaginable)
Appropriate surgical candidate for spinal cord stimulator

Exclusion Criteria

Severe Autonomic Neuropathy as measured by the composite autonomic scoring scale (10 point scale) with a score ≥ 7
History of sympathectomy
Uncontrolled arterial hypertension (Systolic Blood Pressure >160)
Baseline Foot TcPO2 < 10 mmHg to exclude patients with severe peripheral arterial disease
Hemoglobin A1c > 8%
Stable opioid regimen with oral morphine equivalent ≥ 100 mg/day
Alternative principle cause for peripheral neuropathy or lower extremity neuropathic pain
Disruptive psychiatric disorder (screened for during preoperative psychiatric evaluation)
Pending litigations
Women of child bearing potential unwilling to use contraception or found to be pregnant as part of perioperative screening
Patients unable to hold medications that would impact autonomic testing

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Spinal Cord Stimulator Implant	High Frequency Spinal Cord Stimulator	Spinal Cord Stimulator implant

Primary Outcome Measures

Name	Time	Method
Positive Pain	baseline, 12 months	Numeric Rating Scale used to assess pain from a scale of 0 (no pain) to 10 (worst possible pain)
Pain Assessment	Baseline, 12 months	Pain measurement using a Visual Analog Pain Scale by placing an X in the box to indicate the severity of pain from no pain to intolerable pain. The X in the box translates to a score of zero for no pain and increases by an additional 0.5 up to a high score of 10 which would be intolerable pain.
Neuropathy Impairment Score (NIS)	Baseline, 12 months	Subject's scores neuropathic deficits using a scale of 0-4 (zero=normal, 4=paralysis) to measure muscle weakness. The NIS score is a measure of neurologic impairment. The NIS Score has a range of 0 to 244. Lower scores indicate higher function, higher scores indicate lower function.
Modified Leads Assessment of Neuropathic Symptoms and Signs	baseline, 12 months	Questionnaire to identify and analyze pain by answering yes/no which translates to scores from 0-24. A score of 12 or more suggests pain of predominantly neuropathic origin.
Neuropathy Symptoms and Change (NSC) Score	baseline, 12 months	Validated questionnaire that evaluates change in neuropathy symptoms, including symptoms of weakness, sensory symptoms, and autonomic symptoms. Answers to questionnaire are yes/no and if yes, then degree of severity is evaluated with a plus one(slight), plus two (moderate) and plus three (severe). Questionnaire screens the presence and severity of diabetic peripheral neuropathy. Change in severity of symptoms are compared over time. Total scores range from 0 - 114, lower scores reflect no neuropathy symptoms, higher scores reflect more neuropathy symptoms.
Oswestry Disability Index	Baseline, 12 months	Questionnaire examines perceived level of disability in 10 everyday activities of daily living including pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life, social life and traveling. The 6 statements are scored from 0 to 5 scale, zero meaning no disability. The final score ranges from 0-100 with a score of 0-20 equals minimal disability, 21-40 equals moderate disability, 41-60 equals severe disability, 61-80 equals crippled and 81-100 equals bed-bound.
Lower Limb Function Test	Baseline, 12 months	Test for lower limb function in which the subject will need to walk on toes, walk on heels, and arise from kneeled position, each test is marked as not applicable, normal or abnormal. The examination assesses each component for the left and right side separately. If the test is normal, it is given a score of 0, and if it is abnormal, a score of 1. Not applicable scores a zero. Total scores range 0-6. Therefore, the maximum score of 6 indicates abnormality in all 3 components bilaterally and a minimum score of 0 indicates a normal result for all 3 components bilaterally.

Secondary Outcome Measures

Name	Time	Method
Body Mass Index (BMI)	Baseline, 12 months	Subject's BMI calculated as weight in kilograms divided by height in meters squared. Uses measurements of height and weight obtained during study (with appropriate metric conversions)
Hemoglobin A1c	Baseline, 12 months	Hemoglobin is a protein within red blood cells. As glucose enters the bloodstream, it binds to hemoglobin, or glycates. The more glucose that enters the bloodstream, the higher the amount of glycated hemoglobin. An A1C level below 5.7 percent is considered normal. Reported as percentage of glycated hemoglobin
Forearm Sweat Volume Quantitative Axon Reflex Sweat Test (Q-SWEAT)	baseline, 12 months	Test that measures the rate and volume of sweat to determine the severity and pattern of autonomic disorders. As measured by µL/cm²
Height	Baseline, 12 months	Subjects calculated height in centimeters.
Weight	Baseline, 12 months	Subjects calculated weight in kilograms
Patient Health Questionnaire	Baseline, 12 months	Screens for the presence and severity of depression with 9 questions in a scale of 0-3. Zero=not at all, 1=several days, 2=more than half the days, 3=nearly every day. Total score range 0 - 27. A total score of 0-4=minimal depression, 5-9=mild depression, 10-14=moderate depression, 15-19=moderately severe depression, 20-27=severe depression
Proximal Leg Laser Doppler Flowmetry (LDF)	Baseline, 12 months	Laser Doppler velocimetry is used in hemodynamics research as a technique to partially quantify blood flow in human tissues such as skin. Within the clinical environment, the technology is often referred to as laser Doppler flowmetry (LDF). As measured in perfusion units (p.u.)
Extensor Digitorum Brevis Muscle Nerve Conduction	Baseline, 12 months	A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. As measured by amplitude (AMP) milliamp (mA)