Neuromodulation: an alternative treatment for refractory chest pain. Ferdinand J. Formoso, D.O., FAAPMR, DAPM. Coastal Spine & Pain Center

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1 Neuromodulation: an alternative treatment for refractory chest pain Ferdinand J. Formoso, D.O., FAAPMR, DAPM Coastal Spine & Pain Center

2 About Me Bachelors, University of Buffalo (Psychology) Doctorate, NYCOM Residency, St. Barnabas Hospital General Surgery Residency, Temple University PM&R Fellowship, Temple University Pain Medicine Founder, Coastal Spine & Pain Center

3 Introduction Pain now recognized as one of the greatest health care crises of our time $100 billion annually in direct health care costs $ billion annually in total costs More than any other health issue #1 reason for missed work in USA one of the most common reasons patients seek medical attention study of pain is currently one of the most academically active endeavors

4 Introduction Spinal cord stimulation has its historical roots in the days of the Roman Empire 46 AD Scribonius Largus placed torpedo fish on the heads people with headaches proximity to electrical eels and fish would mitigate pain Since 1967, 250,000+ neurostimulators have been surgically implanted worldwide Modern foundation: Gate Control theory of pain

5 Gate Control Theory of Pain Published in 1965 by Ronald Melzack and Patrick Wall Proposed a mechanism in which the nervous system interprets and regulates pain signals First to propose a cortical component in relation to pain interpretation Three main components of the gate : the substantia gelatinosa the dorsal column afferents the central transmission cells

6 Gate Control Theory of Pain Spinal cord is continually bombarded by incoming nerve impulses even in the absence of obvious stimulation. small diameter A-delta and C-fibers typically inhibited by the larger A-beta fibers in the resting state set the gate in a more closed position Foundation for spinal cord stimulation

7 Spinal Cord Stimulation Spinal cord stimulation (SCS) is safe and effective in use for over 40 years implantable pulse generator is inserted under the skin (similar to a pacemaker) leads are placed into the epidural space next to the spinal cord signals sent to spinal cord create paresthesias, masking the pain signals (Gate Control Theory) high frequency stimulation now available, which is unperceivable Reversible procedure surgically implanted device can be removed Trial procedure to confirm efficacy

8 SCS: Patient Selection No set algorithm for selection When is SCS appropriate? Treatment of severe chronic neuropathic pain Failure of less invasive pain management treatments Typical patients are at the end of the road

9 The Spinal Cord Stimulator system consists of four components: Leads/Extension wiring Pulse generator Remote control Charging system

10 The Spinal Cord Stimulator

11 The Spinal Cord Stimulator Leads come in two varieties: percutaneous (cylindrical) surgical (paddle), implanted through a small laminotomy. Percutaneous leads: 4, 8, 16 electrodes Surgical leads are typically available in many array formats

12 Tiny incision is made to place an introducer needle. Lead is then advanced into the epidural space near the spinal cord External trial stimulator is connected, producing the electrical impulse

13 Trial Procedure Patient is awake while a computer guides the pain-masking signals through the electrodes to provide optimal pain relief

14 Trial Procedure Patient wears the remote-controllable system on a belt for 5-14 days

15 Trial Procedure Anatomy of success: Is there a greater than 50% pain relief? Is there functional improvement? Tolerate the sensation of paresthesias? Can the patient operate the system? Typically, 70% of trials will go on to permanent placement My trial to implant ratio is 92%

16 Implantation

17 Neuromodulation Applications Multitude of applications, ever expanding: Back pain Post-laminectomy pain Limb pain Phantom pain CRPS Chronic neuropathy pain Headaches Coccydynia Prostadynia Vulvodynia Chronic post-operative pain Interstitial cystitis Mesenteric ischemia Peripheral vascular disease Angina pectoris

18 SCS for Refractory Chest Pain

19 SCS for Refractory Chest Pain 150,000 people receiving standard medical treatment experience no relief of symptoms 1980s: TENS improves perfusion and pain SCS for angina is widespread in Europe Electrodes placed at T1-T2 level Patients with stable angina, who are not revascularization candidates

20 SCS for Refractory Chest Pain Mechanism of action, several theories: inhibition of nociceptive impulses (gate control) release of mediators resulting in vasodilatation substance P, prostacyclin, and calcitonin gene-related peptide involvement of vasodilating neurotransmitters vasoactive intestinal peptide, serotonin, gamma-aminobutyric acid, prostaglandins, and nitric oxide inhibits sympathetically-maintained vasoconstriction

21 SCS for Chest Pain: Concerns The issue of SCS depriving the patient of anginal warning signals has always been a concern. Even though SCS elevates the anginal threshold, data suggests they can still feel significant cardiac events. In a retrospective study of 517 patients, no increase in mortality was noted, and patients were aware of significant ischemic events determined by Holter monitoring. 1 Reluctance to use this option on the part of clinicians is likely due to treatment paradigms emphasizing revascularization. 2

22 SCS for Chest Pain: The Data RCT electrical stimulation versus coronary artery bypass surgery (ESBY) study, 1998: 83.7% self-estimated treatment effect statistically significant decrease in angina attacks significantly fewer nitrates than at baseline 84% reported symptomatic improvement at 2 yrs significant improvement over baseline in activities of daily living and social activity scores Findings equivalent to CABG group

23 SCS for Chest Pain: The Data ESBY study: 5-year mortality equal between groups no difference in the % of cardiac deaths smaller RCT by Hautvast et al: Nitrate consumption, ischemic episodes at rest and with exercise, and pain significantly decreased. mortality rates of 13.7% in their CABG group versus 1.9% in their SCS group four-fold increase in cerebrovascular events in the CABG group

24 SCS for Chest Pain: The Data 1,2,3,4 Exercise duration and time to induce angina symptoms significantly increased in the SCS group compared with the controls. 1 de Jongtse MJ, Haaksma J, Hautvast RW, Hillege HL, Meyler PW, Staal MJ, et al: Effects of spinal cord stimulation on myocardial ischaemia during daily life in patients with severe coronary artery disease. A prospective ambulatory electrocardiographic study. Br Heart J 71: , Hautvast RW, DeJongste MJ, Staal MJ, van Gilst WH, Lie KI: Spinal cord stimulation in chronic intractable angina pectoris: a randomized, controlled efficacy study. Am Heart J 136: , Jessurun GA, DeJongste MJ, Hautvast RW, Tio RA, Brouwer J, van Lelieveld S, et al: Clinical follow-up after cessation of chronic electrical neuromodulation in patients with severe coronary artery disease: a prospective randomized controlled study on putative involvement of sympathetic activity. Pacing Clin Electrophysiol 22: , Eddicks, S. et. al.. Thoracic spinal cord stimulation improves functional status and relieves symptoms in patients with refractory angina pectoris: the first placebo-controlled randomised study. Heart 93: , 2007.

25 Di Pede, et al, Prospective study of 104 patients Significant improvement of angina symptoms occurred in 73% of patients. The Canadian Cardiovascular Society angina category improved by one or more classes in 80% and by two or more classes in 42% of patients. Rate of hospital admissions and days spent in the hospital secondary to angina were significantly reduced (p, ). Di Pede F, Lanza GA, Zuin G, Alfieri O, Rapati M, Romano M,et al: Immediate and long-term clinical outcome after spinal cord stimulation for refractory stable angina pectoris. Am J Cardiol 15: , 2003

26 SCS for Chest Pain: The Data Yu, et al: A retrospective study of 24 patients with angina who underwent SCS confirmed these results. 2 Significant decrease in frequency of angina episodes, from a median of 14 to 2.3 attacks per week, Decreased nitroglycerin intake, from a median of 27.5 to 1.5 doses per week. Canadian Cardiovascular Society angina class improved from a median of Class 3 to Class 2 (p, 0.001). These patients had an increasing rate of hospitalization before SCS, at 1 year of follow up the duration of hospitalization decreased to a median of 0 days/patient/year (p,0.001). Yu W, Maru F, Edner M, Hellstrom K, Kahan T, Persson H: Spinal cord stimulation for refractory angina pectoris: a retrospective analysis of efficacy and cost-benefit. Coron Artery Dis 15:31 37, 2004

27 SCS for Refractory Chest Pain, Summary Randomized studies on SCS 1,2,3, including one placebo controlled study 4 and one study examining sub-sensory stimulation 5 have demonstrated a reduction in angina complaints decreased use of short-acting nitrates perceived improvement in quality of life increased exercise capacity The beneficial effects last for at least 1 year in 80% of patients, with the increased exercise capacity and improved quality of life being reported in 60% of patients for up to 5 years. 1. Hautvast RW, DeJongste MJ, Staal MJ, et al. Spinal cord stimulation in chronic intractable angina pectoris: a randomized, controlled efficacy study. Am Heart J 1998;136: Mannheimer C, Eliasson T, Augustinsson LE, et al. Electrical stimulation versus coronary artery bypass surgery in severe angina pectoris: the ESBY Study. Circulation 1998;97: De Jongste MJ, Hautvast RW, Hillege HL, et al. Efficacy of spinal cord stimulation as adjuvant therapy for intractable angina pectoris: a prospective, randomized clinical study. Working Group on Neurocardiology. J Am Coll Cardiol 1994;23: Eddicks, S. et. al.. Thoracic spinal cord stimulation improves functional status and relieves symptoms in patients with refractory angina pectoris: the first placebo-controlled randomised study. Heart 2007;93: R Moore, D Groves, J Nolan, D Scutt, J Pumprla, MR Chester Altered short term heart rate variability with spinal cord stimulation in chronic refractory angina: evidence for the presence of procedure related cardiac sympathetic blockade. Heart 2004;90:

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