• Greater than 30% Pain Reduction measured by using Brief Pain Inventory (BPI #12) at each time point without increasing pain medication -Range of motion will be quantified using a goniometer -Motor functions will be measured by Fugl-Meyer Test [ Time Frame: From baseline to follow-up ] [ Designated as safety issue: No ]
• Range of Motion: pain-free passive shoulder abduction, flexion and external rotation will be quantified. [ Time Frame: baseline to end of study ] [ Designated as safety issue: No ]
• -Interference of shoulder pain in daily activities and function measured by using BPI#23 -Quality of Life assessed by using he EuroQol -Reported use of pain medication -Examined for shoulder subluxation -Examined for cutaneous shoulder sensation [ Time Frame: baseline to end of study ] [ Designated as safety issue: Yes ]

The goal of this research study is to investigate the safety and effectiveness of 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 decrease use of pain medication. CAUTION--Investigational device. Limited by Federal law to investigational use.

This is a prospective, dual-center, randomized, controlled, double-blinded parallel study designed to evaluate the feasibility and safety of using the 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 study with a two-year follow up.

• Device: Bioness Battery Powered Microstimulator
• Device: Battery-Powered Microstimulator (BBPM)

• Active Comparator: The BBPM is programmed to deliver set therapeutic stimulation parameters for the first 12 weeks of the study.
• Placebo Comparator: The BBPM will be programmed for the first 12 weeks of the study to deliver short bursts of extremely low amplitude electrical stimulation at very wide time intervals to give appearance, impression, and sensation of therapeutic treatment. After 24 weeks, they will be reprogrammed to receive therapeutic stimulation.

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)