SBIR-STTR Award

Shoulder pain is a common complication of hemiplegia occurring in 70-84% of stroke patients with a paralyzed upper extremity. A painful shoulder frequently results in decreased functional independence and poor motor recovery. Inferior subluxation of the glenohumeral joint is the major cause for the poststroke shoulder pain. Conventional intervention using slings often causes complications from immobilization. Recently, electrical stimulation of the shoulder muscles has been shown effective in reducing or preventing poststroke subluxation by a few pilot studies. Existing surface stimulation systems, however, can not be widely accepted because of poor muscle selectivity, accompanying pain and difficulty in daily application of the electrodes. We propose to use a percutaneous intramuscular stimulation approach to make the stimulation more effective, less painful and easier for daily use for several months. A miniature, programmable, multi-channel stimulator will be developed to drive a set of fine wire electrodes chronically indwelled inside the muscle belly. These electrodes are to be implemented by a hypodermic needle and can be easily withdrawn at the end of use. Preliminary clinical tests will be conducted to establish implantation procedure, stimulation protocol, and evaluation methodology. Feasibility of the project shall be determined by prototype device performance and initial medical outcomes.

Thesaurus Terms:
arm, biomedical equipment development, disease /disorder prevention /control, electronic stimulator, implant, joint disorder, stroke clinical biomedical equipment, electrostimulus, microelectrode, muscle stimulant clinical research, human subjectNational Institute of Child and Human Development (NICHD)

Shoulder pain is a common complication of hemiplegia occurring in 70 to 84% of stroke survivors with a paralyzed upper extremity. Inferior subluxation of the glenohumeral joint is the major cause for the pain. Conventional intervention using slings often causes complications from immobilization. Electrical stimulation of the shoulder muscles has been shown effective in managing post-stroke subluxation in a few pilot studies. Existing surface stimulation systems, however, can not be widely accepted because of stimulation-induced pain, poor muscle selectivity, and difficulty in daily application of electrodes. We proposed to use a percutaneous intramuscular approach to make the stimulation less painful, more selective, and easier for daily use. A miniature, programmable stimulator has been developed in Phase I to drive a set of fine wire electrodes that are inserted into the muscles by a hypodermic needle. Preliminary clinical tests showed that the device and treatment are will accepted by the clinicians and their patients: and the intervention may be effective for the indicated use. Further development of the device and a larger scale, controlled clinical trial will be conducted during the proposed Phase II study to complete a pre-production device and to attain statistical data on the effectiveness of this new medical intervention. PROPOSED COMMERCIAL APPLICATION: The proposed stimulation system is expected to be prescribed to approximately 10 percent of the stroke survivors who have manifested shoulder subluxation or have been diagnosed with significant risk of developing shoulder subluxation. Using this estimate of patient number and assuming a unit price of $900, this product is anticipated to have annual sales of several million dollars.