Acute Human Study: StimRouter for Peripheral Nerve Stimulation of Discrete Peripheral Nerves

Study Overview
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Brief Summary
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This study is being done to see how well a new investigational medical device, the StimRouter (STR) System, will work to treat the chronic pain in people who have failed previous treatments for Carpal Tunnel Syndrome (CTS) pain, including surgery. These people have been treated for CTS pain before including surgical carpal tunnel release, but without good results, and they are still having pain. The study will look at both the good and bad effects of the StimRouter System for treating this kind of pain and as a general peripheral nerve stimulation device for treating chronic pain. The study will also help to understand other possible uses for the StimRouter System.

Detailed Description
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This is a prospective, single-center, open label study designed to evaluate the clinical use of the StimRouter (STR) as a peripheral nerve stimulation device for the treatment of chronic pain. The clinical study is proposed to serve as an evaluation of the preliminary StimRouter design, proposed implantation techniques, electrical stimulation parameters, and outcome measures for the StimRouter. The current study will utilize the median nerve (in the context of carpal tunnel syndrome (CTS), status-post a single failed carpal tunnel release (CTR) surgery)as a model to represent the device's more general intended use as a peripheral nerve stimulator to treat chronic pain.

Official Title
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Acute Human Study: StimRouter for Peripheral Nerve Stimulation of Discrete Peripheral Nerves

Conditions
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Unilateral Carpal Tunnel Syndrome

Intervention / Treatment
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* Device: StimRouter System


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years of age or older Chronic peripheral pain persisting for greater than or equal to 3 months diagnosed previously as a mononeuropathy of the median nerve at the level of the carpal tunnel (i.e., diagnosed CTS) Average chronic pain level greater than or equal to 5/10 [on 0-10 numeric rating scale (NRS) (BPI#14)], where such pain is attributed to injury, irritation, or entrapment of the median nerve at the level of the carpal tunnel (i.e., diagnosed CTS) Failure of a single prior carpal tunnel release surgery to provide relief, where such failed surgery was performed greater than or equal to study entry Able to tolerate stimulation (TENS) Temporary pain relief is achieved by local anesthetic block of the target median nerve suspected to be the source of chronic pain symptoms Ability to give informed consent and understand study requirements Ability to quantify pain using a 0-10 numeric rating scale [A screening tool will be used to ensure that subjects can rate 3 common pain scenarios (mosquito bite, stubbed toe and broken bone) on a 0-10 NRS relative to each other, with mosquito bite < stubbed toe < broken bone] Willing and able to understand and comply with all study-related procedures during the course of the study Motivated to maintain an accurate diary for the study duration Exclusion Criteria: Metal implants in the forearm Active infection Active or existing skin disorder or irritation which, at the physician's discretion, contraindications use of skin gel electrodes Allodynia Regular use of antiplatelet medications [e.g., aspirin, ticlopidine (Ticlid), clopidogrel (Plavix), tirofiban (Aggrastat), and eptifibatide (Integrilin)] Anticoagulated (taking warfarin or heparin, including fractionated heparin) or has a bleeding disorder Cardiac pacemaker Implanted neurostimulator (e.g., spinal cord, deep brain, vagus nerve stimulator) or implanted pump or infusion device History of cardiac arrhythmia with homodynamic instability Untreated drug habituation or dependence Psychologically or medically unstable Uncontrolled seizures (averaging > 2 seizures per month) Pregnant or plan on becoming pregnant or breastfeeding during the study period Currently require, or likely to require, diathermy and/or MRI during the study duration History of adverse reactions to local anesthetic (e.g., lidocaine)

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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: StimRouter (SR) for CTS<br>Percutaneous implantation of StimRouter System | Device: StimRouter System<br>* Implanted with StimRouter System receive 6 hours (or less if not tolerated by the Subject)of electrical therapeutic stimulation each day for a total of 5 days (from start of successful programming)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant Success | Success of device implantation was defined as uncomplicated minimally-invasive implantation of the StimRouter Lead near the targeted peripheral median nerve, resulting in production of desired paresthesias in the sensory distribution of the median nerve when active peripheral nerve stimulation was applied. This outcome parameter was intended to serve as an indication that the lead and electrode stimulating positions could be correctly placed while still maintaining the minimal invasiveness of the procedure. Fluoroscopic imaging was used to document positioning of the StimRouter Lead and, by applying stimulation from a commercially available Dakmed External Pulse Generator (EPG) to the StimRouter Lead, desired paresthesia response was confirmed. | at device implantation procedure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patent Satisfaction | Numerical rating scale (NRS) of 0-10 where 0 = not satisfied and 10 = very satisfied | Day 5 after final stimulation | 
| Percent of Participants Reporting Pain Change From Baseline to Day 5 | Brief Pain Inventory (BPI) questions 14 and 15 were used to measure pain change after 5 days use of StimRouter System. In the BPI, an 11-point numerical rating scale (NRS) is used to rate pain intensity, where zero (0) indicates ''no pain'' and 10 indicates ''pain as bad as you can imagine.'' At enrollment, participants circled the number that best described how much baseline pain they had 'on average' (BPI #14). After enrollment and during the study, patients circled the one number that best described how much pain they had at that time 'right now' (BPI #15). The percent of participants with change from Baseline to Day 5 was calculated. | Day 5 | 
| Mean Change in Pain Achieved by Participants Who Reported Pain Change From Baseline to Day 5 | Using Brief Pain Inventory questions 14 and 15, those 9 subjects who had pain change from Baseline to Day 5 were analyzed to determine change in pain for the overall group. In the BPI, an 11-point NRS is used to rate pain intensity, with a 0 for ''no pain'' and a 10 for ''pain as bad as you can imagine.'' At Baseline, patients circled the number that best described how much baseline pain they had 'on average' (BPI #14). During the study, patients circled the one number that best described how much pain they had at the time 'right now' (BPI #15). | Day 5 after final stimulation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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wrist, hand, pain, failed CTR, carpal tunnel syndrome, CTS, CTR, carpel tunnel release, Peripheral nerve, Median nerve