Electrical Stimulation for the Treatment of Post-Stroke Shoulder Pain

A Prospective Multi-Center Pilot Study of the SPR™ System for the Treatment of Post-Stroke Shoulder Pain

Post-stroke shoulder pain is defined as pain in the shoulder area that starts after a person has had a stroke. The SPR System is an investigational device that is being studied for the relief of post-stroke shoulder pain. The SPR System uses electrical stimulation and includes a Trial Stage (where a temporary system is used to see if the subject may benefit from this type of therapy) and may include an Implant Stage (where a small device is implanted under the skin in the chest). The SPR System delivers mild electrical stimulation to the shoulder where the subject feels pain. This research study will evaluate the effect of electrical stimulation on shoulder pain. Individuals who are over the age of 21, who had a stroke at least six months ago, who experience shoulder pain, and have tried other therapies for their shoulder pain, may be eligible to participate in the first stage of the SPR System. Subjects meeting the specified success criteria at the conclusion of the SPR Trial Stage who experience a return of pain within 6 months of completion of the Trial Stage may be eligible for the second stage (SPR Implant Stage). This research study lasts a little over 3 years and may include 17 visits to the study doctor and at least 8 telephone calls from study staff.

electrical stimulation, neurostimulation, neuromodulation, shoulder pain, post-stroke shoulder pain, hemiplegic shoulder pain

The SPR System is an investigational two-staged device which delivers stimulation to the shoulder. Subjects with chronic post-stroke shoulder pain who meet eligibility criteria for the first stage (SPR Trial Stage) will receive a temporary Lead and External Stimulator. Subjects who qualify and who agreed to proceed will advance to the second stage (SPR Implant Stage) which uses an Implantable Pulse Generator (IPG) and Implantable Lead. Subjects will be followed until 36-months after IPG stimulation has been started.

The SPR System is an investigational two-staged device which delivers stimulation to the shoulder. Subjects with chronic post-stroke shoulder pain who meet eligibility criteria for the first stage (SPR Trial Stage) will receive a temporary Lead and External Stimulator. Subjects who qualify and who agreed to proceed will advance to the second stage (SPR Implant Stage) which uses an Implantable Pulse Generator (IPG) and Implantable Lead. Subjects will be followed until 36-months after IPG stimulation has been started.

Subjects were asked to report their worst pain score on an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The average scores across subjects were reported for Baseline, 3-weeks (End of Placebo), and 6-weeks (End of Treatment).

Subjects were asked to report their worst pain score on an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The average scores across subjects were reported for 3-weeks, 6-weeks, 12-weeks, 6-months, 9-months, 12-months, 24-months, and 36 months post IPG-Stim ON.

3-weeks, 6-weeks, 12-weeks, 6-months, 9-months, 12-months, 24-months, and 36 months post IPG-Stim ON (Implant Stage)

At each study visit following the baseline assessment at Visit 1, subjects were questioned if any changes in their medical status or condition had occurred since their previous visit. If the subject experienced a change that was an adverse event, an Adverse Event Form was completed by the site. The number of subjects that experienced at least one study-related adverse event is reported here.

Total of 86 months (from when the first subjects enrolled to when the last subject completed the study)

The number of subjects who were a trial stage success is presented. Trial Stage Success for each subject was determined by a 2-point reduction in Brief Pain Inventory question 3 at the end of t.he Trial Stage beyond any placebo effect.

Number of subjects who were an Implant Stage Success is presented. Implant Stage Success for each subject was determined by a 2-point reduction in Brief Pain Inventory question 3 at 12-week post IPG stimulation ON beyond any placebo effect.

Subjects were asked to rate the degree to which their pain has interfered with general activity, mood, walking ability, normal work, relations with other people, sleep and enjoyment of life on an 11-point numerical rating scale where 0 represents "does not interfere" and 10 represents "completely interferes." The average scores across subjects were reported for Baseline, 3-weeks (End of Placebo), and 6-weeks (End of Treatment).

Pain-Free Passive Range of Motion (ROM) was assessed. The average ROMs for all subjects were reported for Baseline, 3-weeks (End of Placebo), and 6-weeks (End of Treatment).

Subjects were asked to complete the Short Form Health Survey Version 2 (SF-36v2) to assess basic physical functioning and emotional well-being regardless of the disease or treatment. The SF-36 consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The lower the score the more disability. The higher the score the less disability i.e., a score of zero is equivalent to maximum disability and a score of 100 is equivalent to no disability. To calculate the scores it is necessary to purchase special software. The eight domains are physical functioning, role limitations due to physical problems, social functioning, bodily pain, general mental health, role limitations due to emotional problems, vitality, and general health perceptions. The mean scores for Baseline, 3-week (End of Placebo), and 6-week (End of Treatment) were reported.

Subjects were asked to document pain medication, doctor visits, supplies, related treatments, need for caregivers, time spent in skilled nursing facilities, and lost work due to their shoulder pain. This data was collected from subjects at Baseline and asked to recall this data for the 6-months prior to study enrollment. National average costs were not available for these data points, and therefore the overall economic impact of shoulder pain could not be reported.

Subjects were asked to complete the Beck Depression Inventory Version 2 (BDI-II), a 21 question survey to assess depressive symptoms. Each answer was scored on a scale value of 0 to 3 and a sum was taken for all 21 questions. Higher total scores indicated more severe depressive symptoms. The standardized cutoffs used were: 0-13: minimal depression, 14-19: mild depression, 20-28: moderate depression, and 29-63: severe depression. Mean BDI-II scores were calculated across subjects and were reported for Baseline, 3-weeks (End of Placebo), and 6-weeks (End of Treatment).

Subjects completed a sponsor-developed survey with questions pertaining to their feelings about the Smartpatch Stimulation System as a method for managing post-stroke shoulder pain.

The Patient Global Impression of Change asks subjects to rate their improvement with treatment on a 7-point scale ranging from "very much worse" to "very much improved". The subjects combine all the components of their experience into one overall score.

Subjects were asked to complete the Short Form Health Survey Version 2 (SF-36v2) to assess basic physical functioning and emotional well-being regardless of the disease or treatment. The SF-36 consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The lower the score the more disability. The higher the score the less disability i.e., a score of zero is equivalent to maximum disability and a score of 100 is equivalent to no disability. To calculate the scores it is necessary to purchase special software. The eight domains are physical functioning, role limitations due to physical problems, social functioning, bodily pain, general mental health, role limitations due to emotional problems, vitality, and general health perceptions. The mean scores for 3-weeks, 12-weeks, 6-months, 9-months, and 12-months, post IPG-Stim ON were reported.

Subjects were asked to rate the degree to which their pain has interfered with general activity, mood, walking ability, normal work, relations with other people, sleep and enjoyment of life on an 11-point numerical rating scale where 0 represents "does not interfere" and 10 represents "completely interferes." The average scores across subjects were reported for 3-weeks, 6-weeks, 12-weeks, 6-months, 9-months, and 12-months post IPG-Stim On.

Pain-Free Passive Range of Motion (ROM) was assessed. The average ROMs for all subjects were reported for 3-weeks, 12-weeks, 6-months, 9-months, and 12-months post IPG-Stim ON.

Subjects were asked to complete the Beck Depression Inventory Version 2 (BDI-II), a 21 question survey to assess depressive symptoms. Each answer was scored on a scale value of 0 to 3 and a sum was taken for all 21 questions. Higher total scores indicated more severe depressive symptoms. The standardized cutoffs used were: 0-13: minimal depression, 14-19: mild depression, 20-28: moderate depression, and 29-63: severe depression. Mean BDI-II scores were calculated across subjects and were reported for 3-weeks, 12-weeks, 6-months, 9-months, and 12-months post IPG-Stim ON.

The Patient Global Impression of Change asks subjects to rate their improvement with treatment on a 7-point scale ranging from "very much worse" to "very much improved". The subjects combine all the components of their experience into one overall score.

3-weeks, 12-weeks, 6-months, 9-months, 12-months, 24-months, and 36-months Post IPG-Stim ON (Implant Stage)

Subjects completed a sponsor-developed survey with questions pertaining to their feelings about the IPG System as a method for managing post-stroke shoulder pain.

Subjects were asked to assess their arm impairment using the Stroke Upper Limb Capacity Scale (SULCS) test. The SULCS is a validated upper limb capacity scale which includes tasks directly related to activities of daily living individuals experience in their home environment. The SULCS consists of 10 items, with each item having a possible score of 0 or 1: 3 items for arm capacity without active hand capacity; 4 items for arm capacity and basic hand capacity; and, 3 items for complex hand capacity. These scores were summed with a higher score indicating better capacity, with 10 being the max score. The average score across subjects were reported for Baseline, 3-weeks (End of Placebo), and 6-weeks (End of Trial Stage).

Trial Stage Inclusion Criteria: At least 21 years of age Post-stroke shoulder pain Trial Stage Exclusion Criteria: Use of habit-forming (narcotic) medications History of recurrent skin infections Bleeding disorder Parkinson's Disease, Spinal Cord Injury, traumatic brain injury, Multiple Sclerosis, or complex regional pain syndrome Heart arrhythmia or artificial heart valves Uncontrolled seizures Implanted Electronic Device Implant Stage Inclusion Criteria Had a "return of pain" defined as an increase in pain of at least 2 points compared to the pain intensity score at Visit 5 and has a pain intensity score of at least 4

Nguyen VQ, Bock WC, Groves CC, Whitney M, Bennett ME, Lechman TE, Strother R, Grill JH, Stager KW, Chae J. Fully implantable peripheral nerve stimulation for the treatment of hemiplegic shoulder pain: a case report. Am J Phys Med Rehabil. 2015 Feb;94(2):146-53. doi: 10.1097/PHM.0000000000000173.