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Percutaneous Peripheral Nerve Stimulation (PNS) for Hemiplegic Shoulder Pain John Chae, MD.

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Presentation on theme: "Percutaneous Peripheral Nerve Stimulation (PNS) for Hemiplegic Shoulder Pain John Chae, MD."— Presentation transcript:

1 Percutaneous Peripheral Nerve Stimulation (PNS) for Hemiplegic Shoulder Pain John Chae, MD

2 Describe the development of percutaneous PNS for the treatment of hemiplegic shoulder pain Assess the efficacy of percutaneous PNS in reducing hemiplegic shoulder pain Discuss potential mechanisms of action Objectives

3 Investigational device SPR Therapeutics Consultant Chief Medical Advisor Received sponsored research support Funding from NIH Disclosures

4 New Jersey Medical School (Fall, 89) Elective rotation in PMR at Kessler Senior resident: “John, if you can find a solution to hemiplegic shoulder pain you will change the field of pain management!” Where did it all start?

5 Hemiplegic Shoulder Pain High incidence and prevalence: Among all new strokes: ~25% (150,000) at 6-mo; Among all (old and new) stroke survivors: ~10% (600,000) Associated with: Poor motor recovery Poor functional recovery Poor quality of life

6 Stroke Spasticity Weakness Muscle Atrophy Mechanical Instability Subluxation Joint malalignment Reduced ROM Scapular malrotation Micro and macro trauma Inflammation/ degeneration Capsule Tendons Muscles Bursa Capsulitis Tendonitis Tendinosis Muscle tears Bursitis Pain Immobility Complex Regional Pain Syndrome Periosteal traction Sheffler and Chae, Muscle Nerve, 2007 Surface ES

7 Surface Electrical Stimulation Best Practice There is strong evidence that “Functional electrical stimulation improves muscle function, pain, subluxation, and range of motion of the hemiplegic shoulder.” (Teasell et al., Top Stroke Rehabil 2003) Corroborated by: – VA/DoD Practice Guidelines (2005) – Ottawa Panel Evidence-based Clinical Practice Guidelines for Post-stroke rehabilitation. (2006) Not the Standard of Care Unable to tolerate 6-hrs of stimulation per day for 6-wks Need for skilled personnel for: – Reliable electrode placement – Adjustment of stimulation parameters to facilitate tolerance and minimize fatigue

8 Percutaneous PNS using Intramuscular Nerve (IMN™) therapy Not painful Low frequency (12Hz) No daily electrode placement No adjustment of parameters NIA P60A CAUTION: Investigational device. Limited by Federal law to investigational use. Insertion Needle with Electrode in Lumen Stimulating Tip Insulated Lead 1994:

9 Percutaneous PNS Case Report AFFECTED SIDE - PRE-TREATMENT UNAFFECTED SIDE POST-6 WEEK TREATMENT 3-MONTH FOLLOW-UP 19 mm 2 mm5 mm 59 YOM, 18.5 months post-onset of hemiplegia Chae et al,, Am J Phys Med Rehabil 2001; 80: Time (weeks) BPI – NRS (0 -10) Baseline7 6 (post-treatment)4 18 (3-mo FU)0 52 (1-yr FU)0 Shoulder SubluxationShoulder Pain

10

11 Published Percutaneous PNS Studies Demonstrate Clinical Feasibility Case Report: (NIA P60A ) Chae et al, Am J PMR 2001 Case Series 1; N=8 (NICHD R43HD34996; NICHD K12HD010973) Yu et al., Arch PMR 2001; 82: Case Series 2; N=15 (NeuroControl) Renzenbrink and Ijzerman, Clin Rehabil 2004; 18: Stimulation “on”

12 4-lead, Percutaneous PNS Multi-center RCT CAUTION: Investigational device. Limited by Federal law to investigational use. Subjects N = 61 at 6 US sites Chronic stroke survivors Shoulder pain Subluxation Treatment Protocol 4-lead PNS vs. conventional Tx 6h/day x 6-wks of PNS 12-mo FU Endpoints Primary outcomes: Pain & Safety Secondary outcomes: QoL, Subluxation, motor impairment, ADLs, spasticity, ROM NeuroControl Corporation, R44HD34996, K12HD010973

13 EOT 3-mo 6-mo 12-mo Months from Treatment Onset Treatment Post-treatment (Stim ON) (Stim OFF) F=21.2 P<0.001 Yu et al, Arch PMR 2004; Chae et al, Am J Phys Rehabil 2005 Pain relief maintained for at least 12-months after Stimulation Turned Off Brief Pain Inventory – Pain Intensity Months from Treatment Onset F=21.2, p<0.001 * * * *

14 4-lead, Percutaneous PNS Multi-center RCT Safety & Efficacy No serious adverse events Significant pain reduction Maintained to at least 12-mo after stimulation turned off Significant improvement in pain related QOL Mechanism – No Effect On: Subluxation Motor impairment ADLs Spasticity Pain free ROM Clinical Implementation 4-lead procedure was challenging for some investigators

15 Uncertainty…

16 Uncertainty….

17 Back Together Again….

18 Do we need 4 leads? Can we simplify the procedure? Supraspinatus rarely produced strong contractions Trapezius did not cross the glenohumeral joint Middle and posterior deltoids consistently produced strong contractions Can a single electrode activate both posterior and middle deltoid? No need for tunneling Shorter procedure time

19 Single-lead, Percutaneous PNS SPR Therapeutics; NICHD K24HD CAUTION: Investigational device. Limited by Federal law to investigational use. Subjects N = 8 at 1 US site Chronic (>6mos) stroke survivors Hemiplegic Shoulder pain (BPI3 > 4) With or without Subluxation Treatment Protocol 1-lead PNS case series 6h/day x 3-wks of PNS 4-wk FU (protocol) & 12-wk FU (clinical) Endpoints Primary outcomes: Pain (BPI) & Safety Secondary outcomes: QoL (SF-36), ROM Pain interference (BPI), Patient global impression of change (PGIC)

20 Single-lead, Percutaneous PNS SPR Therapeutics; NICHD K24HD Implant Explant Stimulation F=11.0, p<0.001 * * * *

21 Single-lead as Effective as 4-leads

22 Single-lead Case Series Observations  Safety: No significant adverse events, including no infection  Efficacy:  Significant post-stroke shoulder pain reduction  Significant improvement in QOL  Dosage: 3-wks of stimulation appears to be as effective as 6- wks of stimulation in reducing pain at end of treatment  3 subjects without subluxation experienced significant pain reduction  5 subjects exhibited clinical evidence of subacromial bursitis or supraspinatus impingement at baseline based on positive Neer’s sign and test

23 Single-lead, Percutaneous PNS System TechnologyPercutaneous Lead, External Stimulator & Patch Lead Placement Procedure Percutaneous, intramuscular placement near peripheral nerve Short out-patient procedure (<30 min) Placed by non-surgeon Lead: Specifically designed to be anchored in muscle Extensive clinical use with excellent safety profile Easily removed after therapy Therapy3-weeks of stimulation therapy 23 CAUTION: Investigational device. Limited by Federal law to investigational use. Commercially available stimulator used during Study SMARTPATCH™ System by SPR Therapeutics

24 Stroke Spasticity Weakness Muscle Atrophy Mechanical Instability Subluxation Joint malalignment Reduced ROM Scapular malrotation Micro and macro trauma Inflammation/ degeneration Capsule Tendons Muscles Bursa Capsulitis Tendonitis Tendinosis Muscle tears Bursitis Pain Immobility Complex Regional Pain Syndrome Periosteal traction CNS Sensitization PNS (-)

25 Mechanism of PNS Therapy Percutaneous PNS will activate directly low threshold (large diameter) primary afferents -Ia – muscle spindle receptor afferents -Ib – Golgi tendon organ afferents -synchronous activation at stimulation frequency (12 Hz) Activity in large diameter afferents inhibits transmission of pain signals at the spinal cord; Gate theory (Melzack & Wall 1962, 1965) - - Peripheral Nerve Stimulation Noxious stimulation Spikes/Bin In Spinothalamic Tract Neurons Chung et al., 1984

26 Mechanism of PNS Therapy Percutaneous PNS will activate directly: – Efferents: low thresholds (large diameter) α-motoneuron efferents – Causing muscle contraction Muscle Contraction will activate indirectly: – Ia and Ib primary afferents – II joint capsule and cutaneous afferents – asynchronous physiological activation Dis-Sensitization: Pain relief produced by PNS Therapy outlasts the period of stimulation – 3-wks of stimulation produced pain relief for at least 12-wks after EOT – physiological activity in afferents reverses the processes and consequences of sensitization

27 Summary Described the development of percutaneous PNS for the treatment of hemiplegic shoulder pain Assessed the efficacy of percutaneous PNS in reducing hemiplegic shoulder pain Discussed potential mechanisms of action

28 Acknowledgements: Funding SponsorNumberStartEnd NIH-NIAP60A NIH-NICHDR43HD NIH-NICHDK12HD NIH-NICHDR44HD NeuroControlSponsored Clinical Trial NIH-NICHDK24HD SPR TherapeuticsSponsored Clinical Trial NIH-NICHDR01HD

29 Thank You!

30 Percutaneous PNS Case Report AFFECTED SIDE - PRE-TREATMENT UNAFFECTED SIDE POST-6 WEEK TREATMENT 3-MONTH FOLLOW-UP 19 mm 2 mm5 mm 59 YOM, 18.5 months post-onset of hemiplegia Chae et al,, Am J Phys Med Rehabil 2001; 80: Time (weeks) BPI – NRS (0 -10) Baseline7 6 (post-treatment)4 18 (3-mo FU)0 52 (1-yr FU)0 Shoulder SubluxationShoulder Pain

31 Percutaneous PNS Case Series 1, n= Yu et al., Arch Phys Med Rehabil 2001; 82: NICHD R43HD34996; NICHD K12HD010973

32 Percutaneous PNS Case Series 2, n=15 Renzenbrink and Ijzerman, Clin Rehabil 2004; 18: Physical functioning Social functioning Bodily pain Vitality Role emotional Mental Health Role physical General health Favors treatment Improvement (baseline – 24 weeks follow-up) baseline treatment 12 weeks 24 weeks Brief Pain Inventory (numeric rating scale)

33 Chronic Post-stroke Shoulder Pain Subjects achieving Pain Reduction 84% 66% 59% 34% 31% 24% 17% 3% 0% 20% 40% 60% 80% 100% > 2 points> 3 points> 4 points Complete Reduction (Became pain free) Degree of Pain Reduction (11-point scale, 0=no pain, 10=pain as bad as you can imagine) Subjects (%) 4-lead, 6-wk Therapy (N=32) 6-wk Conventional Therapies (N=29) 33 Significant Pain Reduction with 4-Lead Percutaneous PNS Yu et al, Arch PMR 2004; Chae et al, Am J Phys Rehabil 2005

34 1-lead PNS approach as effective as previously evaluated 4-lead PNS approach Pain as bad as you can imagine No pain After 3-weeks of therapy:  1-lead approach resulted in 70% average pain reduction  4-lead approach resulted in 51% average pain reduction 34

35 Percutaneous PNS System using IMN™ Therapy for Hemiplegic Shoulder Pain Clinical Feasibility Demonstrated Chronic Hemiplegic Shoulder Pain Subjects achieving Pain Reduction 84% 66% 59% 34% 31% 24% 17% 3% 0% 20% 40% 60% 80% 100% > 2 points> 3 points> 4 points Complete Reduction (Became pain free) Degree of Pain Reduction (11-point scale, 0=no pain, 10=pain as bad as you can imagine) Subjects (%) 4-lead, 6-wk Therapy (N=32) 6-wk Conventional Therapies (N=29) 1-lead, 3-wk Therapy (N=8) 100% 25% 35 Yu et al, Arch PMR 2004; Chae et al, Am J Phys Rehabil 2005; Wilson et al., in-press; Chae et al., in-review

36 36 IM ES RCT OP Therapy Treatment: 3-wks Follow-up: 3-mo Aim 1: BPI 3 Aim 2: SF-36 Aim 3: Arm Function and EMG activation patterns Stroke survivors with shoulder pain, with or without subluxation; n=24 “Usual Care” OP Therapy Single-lead Pilot RCT vs Usual Care NICHD R01HD059777

37 37 Single-lead, 2-stage PNS Pilot Study SPR Therapeutics, LLC IDE approved Pilot Study N ~ 20 Subjects ~ US sites Case Series Gather preliminary data on the safety, clinical efficacy including quality of life, placebo effect and performance of the SPR 2- stage PNS system Implantable Pulse Generator Implantable Lead External stimulator mounted on surface return electrode Percutaneous Lead CAUTION: Investigational device. Limited by Federal law to investigational use. Short-term, Trial Stage Long-term, Implant Stage

38 Sensitization Loss of inhibitory interneurons (and efficacy) in the dorsal horn of the spinal cord, such that inputs on non- noxious afferents (A-beta) are not inhibited and result in the perception of pain. Abnormal sprouting and growth of terminal axons of non-noxious afferents (A-beta) to make inappropriate connections such that activity in these fibers result in the perception of pain. Changes in functional connectivity between brain regions that can influence the perception of ascending activity as well as the modulation, via descending activity, of sensory signal processing in the spinal cord.

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