Peripheral Nerve Stimulation(PNS) for Subacromial Impingement Syndrome(SIS)

Shoulder pain accounts for 16% of all musculoskeletal complaints in the healthy adult population. Subacromial impingement syndrome (SIS) is the most common cause of shoulder pain. Many patients with chronic pain from subacromial impingement syndrome (SIS) will fail treatment efforts and have longstanding pain. This project will evaluate the efficacy of a novel approach to treatment, percutaneous peripheral nerve stimulation, for participants with chronic shoulder pain due to subacromial impingement syndrome (SIS).

The medical and socioeconomic impact of subacute and chronic shoulder pain is high, resulting in 12 million visits to physicians and over $7 billion in direct costs in the United States. The most common cause is subacromial impingement syndrome (SIS), which accounts for 30% of all shoulder pain. Approximately 35% of patients who present with subacromial impingement syndrome (SIS) are refractory to conservative management. For patients who have failed conservative management, there are no established treatments to reduce the pain. The long-term goal is to develop a therapeutic intervention to reduce pain related to subacromial impingement syndrome(SIS). A pilot trial of 3-week percutaneous peripheral nerve stimulation (PNS) for participants with chronic shoulder pain due to subacromial impingement syndrome (SIS) that was refractory to conservative treatment that showed 60% of participants had successful treatment of pain that lasted at least 3 months. Thus, the primary objective of this 2 site randomized control trial (RCT) is to confirm the findings of this preliminary trial and determine the efficacy of peripheral nerve stimulation (PNS) for chronic subacromial impingement syndrome (SIS). The secondary objectives of this multisite randomized control trial (RCT) is to explore mechanisms of peripheral nerve stimulation (PNS) for the treatment of subacromial impingement syndrome (SIS), and to determine which characteristics can predict successful treatment with peripheral nerve stimulation (PNS). In order to accomplish these objectives, this trial is a multi-site, placebo controlled, double-blinded randomized control trial (RCT) to compare the efficacy of peripheral nerve stimulation (PNS) to sham peripheral nerve stimulation (PNS). Measures of pain, pain interference with activities of daily living (ADLs), capacity for activities of daily living (ADLs), Quality of life (QoL), and measures of central sensitization (pain thresholds, secondary hyperalgesia, and temporal summation) will be measured. Participants will be followed for a total of 24 weeks after treatment has concluded.

Eligibility Criteria:
Inclusion Criteria:

1. Shoulder pain of \>3 months
2. Age\>=21
3. Worst pain in the last week\>=4 (0-10 scale)
4. Ability to check skin and perform dressing changes, independently or with assistance
5. Stable dose of pain medication (Not taking more than than 1 opioid or 1 non-opioid analgesic)

Exclusion Criteria:

1. Current shoulder joint or overlying skin infection, or current bacterial infection requiring antibiotics
2. Other chronic pain syndrome (Pain in another area of the body 15 or more days in the last 30 (more than half of the time) or taking daily analgesics for another pain syndrome)
3. Prior shoulder surgery to ipsilateral shoulder joint (glenohumeral, rotator cuff, acromioclavicular (AC) Joint, etc.)
4. Corticosteroid injection in the ipsilateral shoulder or any other pain relieving treatment in last 12 weeks
5. Uncontrolled bleeding disorder
6. Medical instability based on physician opinion after review of medical information
7. Pregnancy
8. Neurological condition affecting ipsilateral upper limb (such as central neurologic injury/illness, radiculopathy, diabetic amyotrophy, Complex Regional Pain Syndrome, etc.)
9. Current Worker's compensation claim for the ipsilateral shoulder
10. Shoulder instability, severe glenohumeral osteoarthritis(OA) based on patient symptoms and physical examination
11. Ipsilateral shoulder injury due to severe trauma (Fall from greater than standing height; Motor vehicle crashes; Struck by vehicle or other fast-moving projectile (e.g., bullet, baseball, etc.); Assault (i.e., injuries intentionally inflicted by another person))
12. Current osseus fracture in ipsilateral arm
13. Ipsilateral upper limb amputation other than a single digit (digits 2-5, partial or full)
14. Surgical indication for shoulder treatment based on physician opinion
15. Compromised immune system (immunodeficiency or immunosuppression)
16. Current use of a Deep Brain Stimulation (DBS) system, implanted active cardiac implant (e.g. pacemaker or defibrillator), any other implantable neuro-stimulator whose stimulus current pathway may overlap with that of the SPRINT System
17. Patients who have a tape or adhesive allergy
18. Contraindication to Magnetic resonance imaging (metal in body, claustrophobia, body habitus, etc) - exclude from Magnetic resonance imaging (MRI) only