An Implantable Microneuromodulator for the Treatment of Chronic Shoulder Pain in Chronic Post-Stroke Subjects

The goal of this research study is to investigate safety and gather initial effectiveness data for a new implanted device designed to treat chronic shoulder pain in chronic post-stroke subjects. The BBPM weighs less than 0.03 ounces and measures 1" x 0.1". It is implanted into the shoulder to stimulate the axillary nerve. Stimulation of this nerve may reduce shoulder pain, reduce shoulder subluxation, improve motion, improve function, and possibly decrease use of pain medication. CAUTION--Investigational device. Limited by Federal law to investigational use.

This is a prospective, multi-center, randomized, controlled, double-blinded parallel study designed to evaluate feasibility and safety. The primary purpose of this study is to demonstrate the clinical feasibility of implanting the BBPM near a peripheral nerve for the treatment of chronic, intractable, pain in this case represented by chronic regional shoulder pain in hemiplegic stroke patients. This is a 48-week efficacy study with safety data collection throughout the study period and up to 2 years for all available subjects. Each study arm will receive therapeutic level stimulation for a total of 12 consecutive weeks (Weeks 1-12 for Active treatment group and Weeks 24-36 for the sham group) during the 48 weeks.

Eligibility Criteria:
Inclusion Criteria:

* 18 years of age or older
* Chronic post-stroke duration greater than or equal to 6 months
* Unilateral hemiplegic shoulder pain persisting for ≥6 months
* Hemiparesis (shoulder abduction graded \<5/5 on Manual Muscle Testing ipsilateral to the shoulder in which the subject has chronic pain
* Shoulder pain ≥ 6/10 (on 0-10 numeric rating scale (NRS) for worst pain in last week (BPI #12))
* 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 participants can rate 3 common pain scenarios (mosquito bite, stubbed toe and broken bone) on a 0-10 NRS relative to each other.)
* 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:

* Hemineglect (i.e., extinguish to double simultaneous stimulation)
* Shoulder trauma or diagnosed shoulder pathology prior to stroke; history of any shoulder surgery, regardless of whether procedure preceded for followed stroke.
* Need to take \>1 pain medication (opioid or non-opioid) for shoulder pain
* Regular use of pain medication for chronic pain other than shoulder pain
* Anticoagulated (taking warfarin or heparin, including fractionated heparin) or has a bleeding disorder
* Unable, per their prescribing physician, to stop antiplatelet medications (e.g., aspirin, ticlopidine (Ticlid), clopidogrel (Plavix), tirofiban (Aggrastat), and eptifibatide (Integrilin)) for at least 7 days prior to device implantation.
* Cardiac pacemaker
* Implanted neurostimulator (e.g., spinal cord, deep brain, vagus nerve) or implanted pump or infusion device
* Prosthetic heart valve or valvular heart disease requiring antibiotic prophylaxis
* History of cardiac arrhythmia with hemodynamic instability
* Uncontrolled seizures (\> 1 seizure per month)
* Pregnant or plan on becoming pregnant during the study period
* Medical instability
* Currently require, or likely to require, diathermy
* Currently require, or anticipated to require, MRI within 8 weeks of projected device implantation date
* History of adverse reactions to local anesthetic (e.g., lidocaine)