Spinal Cord Stimulation as Alternative to Chronic Opioid Treatment in Chronic Pain Patients Presented by: Sanjay Sastry, M.D FSAM Meeting. March 5, 2010 Tampa, Florida Interventional Pain Management Medicine • Growing as a new specialty • Includes evaluation and treatment of acute and/or chronic pain • Requires that pain physicians receive at least one year of training in pain management post medical degree • Requires knowledge of all of chronic pain therapy options 2 Physicians who often specialize in pain management • Anesthesiologist Other pain practitioners • Neurosurgeon • Acupuncturist • Neurologist • Chiropractor • Orthopedic surgeon • Physical therapist • Physiatrist (PM&R) • Psychiatrist, • Rheumatologist psychologist, or professional counselor 3 4 Pain • Unpleasant sensory or emotional experience • 2 types of pain: acute and chronic • Chronic: – Nociceptive • Somatic • Visceral – Neuropathic • Central • Peripheral 5 Definition of Chronic Pain • Frequent or constant pain that does not respond to the usual treatments • Unlike acute pain, which gets better and goes away in a short time, chronic pain persists for at least several months 6 Cycle of Pain Depression Pain Limited/Loss Stress 7 Nociceptive Pain • Somatic pain arises from: – Bone and joint – Muscle – Skin – Connective tissue • Aching or throbbing • Localized • Visceral pain arises from: – Visceral organs such as GI tract and pancreas • Tumor involvement • Obstruction 8 Neuropathic Pain • Abnormal processing of sensory input by the peripheral or central nervous system • Centrally generated pain • Peripherally generated pain 9 Mixed Pain • Many patients have a combination of both nociceptive and neuropathic pain • Disease or trauma has damaged both nerve cells and other tissues 10 11 Definition of Neuromodulation Neuromodulation is the electrical or chemical modulation of the central nervous system to reduce chronic pain or improve neurologic function. 12 Neuromodulation Devices • Electrical Stimulators and Drug Pumps – Precise delivery of small doses of electricity or drugs directly to targeted nerve sites. 13 Spinal Cord Stimulation (SCS) • Implanted medical device that delivers electrical pulses to nerves in the dorsal aspect of the spinal cord that can interfere with the transmission of pain signals to the brain and replace them with a more pleasant sensation called paresthesia. 14 CNS Pain Management (Theory) • Gate Control Theory • Melzack and Wall, 1968 C FIBER INHIBITORY INTERNEURON PROJECTION AaAb FIBERS NEURON 15 Gate Theory and SCS • SCS implanted near dorsal column stimulates the pain-inhibiting nerve fibers masking painful sensation with a tingling sensation (Parathesia) C FIBER Sensory INHIBITORY SCS INTERNEURON Gate Pain AaAb FIBERS PROJECTION NEURON 16 Overall Goals of SCS Therapy • Position electrode in area of specific neural target • Generate electrical field at target nerve to create paresthesia that overlaps painful area(s) • Program stimulation parameters for 17 Clinical Factors • Indication – Responsive to SCS • Pain Etiology – Pain likely to progress should have device with “extra capacity” • Pain Distribution – Multi site and broad pain patterns often require more leads and electrodes • Patient Factors – Anatomy – Physiology – Selection 18 Device Factors • Stimulation Coverage – Paresthesia is delivered to entire painful segment(s) • Precision of Stimulation – Not delivered to extraneous sites but masks the pain with a tolerable sensation • Sustainability of Therapy – Sustained over the painful anatomical segment 19 How Are Clinical Factors Evaluated? • Patient Selection Process –Correctly diagnosed –Failed lower level therapies –Successfully passed psych evaluation –Patient is motivated –Patient is educated 20 21 Chronic Pain Treatment Continuum Diagnosis Physical Therapy OTC Pain Medications 22 Chronic Pain Treatment Continuum First-Tier Pain Therapies Diagnosis NSAIDs TENS Psychological Therapy Nerve Blocks Physical Therapy OTC Pain Medications 23 Chronic Pain Treatment Continuum Second-Tier Pain Therapies First-Tier Pain Therapies Opioids Neurolysis Thermal Procedures Diagnosis NSAIDs TENS Psychological Therapy Nerve Blocks Physical Therapy OTC Pain Medications 24 Chronic Pain Treatment Continuum Advanced Pain Therapies Second-Tier Pain Therapies Neurostimulation Implantable Drug Pumps Surgical Intervention Neuroablation First-Tier Pain Therapies Opioids Neurolysis Thermal Procedures Diagnosis NSAIDs TENS Psychological Therapy Nerve Blocks Physical Therapy OTC Pain Medications 25 26 Patient Selection Criteria • Pain is neuropathic in origin • Conservative therapies have not provided long term pain relief • Patient is willing and motivated • No contraindications present (pacemakers, need for ongoing MRIs) • Multidisciplinary screening including psychological examination 27 Applications for SCS • Angina • Complex Regional Pain • Failed Back Surgery Syndrome I (CRPS I) Syndrome formerly referred to as • Arachnoiditis Reflex Sympathetic Dystrophy (RSD) • Peripheral Ischemic Pain • Complex Regional Pain • Phantom Limb Pain Syndrome II (CRPS II) • Phantom Stump Pain formerly referred to as • Post-Herpetic Neuralgia CausalgiaPeripheral Neuropathies 28 Failed Back Surgery Syndrome • Post laminectomy syndrome • Non-successful results after back/spine surgery • Diffuse, dull, achy pain in back • Sharp, pricking and stabbing pain in the legs 29 Back Pain • #1 cause for healthcare cost in the United States – $55 billion in healthcare related costs • #1 cause of employee absenteeism – $75 billion in lost worker productivity • #1 ailment cited in worker’s compensation claims – 600,000 lost work day injury cases • Ten million Americans visited doctor • 725,000 fusions and discectomies in 2000 Source: Medpro 30 31 How Are Device Factors Evaluated? • During a Temporary SCS Trial – Leads are implanted – External power source is used to evaluate • Pain relief • Paresthesia coverage • Power requirements • Programming needs • System requirements (RF or IPG) 32 Cost-Effectiveness of SCS SCS is cost effective, as several experts have shown: Bell et al.3 showed that SCS pays for itself within 2.1 years with patients who have clinically effective SCS. Another study by Kumar4 determined the average cumulative cost for SCS therapy for 5 years was $29,123 per patient, less than the per- patient cost of $38,029 for conventional pain therapy. In fact, 15 percent of the SCS-treated patients were able to return to work because SCS provided “superior pain control” and because patients reduced their medications. None of the patients in the study receiving conventional pain therapy were able to return to employment of any kind. 3. Bell GK, Kidd D, North RB. Cost Effectiveness Analysis of Spinal Cord 4. Kumar K, Malik S, Demeria D. Treatment of Chronic Pain with Spinal Cord Stimulation in Treatment of Failed Back Surgery Syndrome. J Pain Stimulation versus Alternative Therapies: Cost-Effective Analysis. Symptom Manage. 1997;13:286-295. Cited by: Stojanovic MP, Abdi S. Neurosurgery. 2002;51:106-116. Spinal Cord Stimulation. Pain Physician. 2002;5(2):156-166. 33 Proposed New Chronic Pain Treatment Continuum Chart from Mekhail NA, Aeschbach A, Stanton-Hicks M. Cost Benefit Analysis of Neurostimulation for Chronic Pain. Clin J Pain. 2004;20:462-468. 34 Reduction of Pain Clinical studies on SCS continue to support the effectiveness of this therapy. The following charts summarize studies of SCS and its effects on the quality of life of patients. Number of Reference Follow Up Results Patients Kumar22 410 8 years 74% had > 50% relief North2 19 3 years 47% had > 50% relief 50%-65% had good to Barolat7 41 1 year excellent relief excellent 68%9.had good to Efficacy of Spinal Cord Buyten8 Spinal North RB, Ketcik 123 VanSharanOakley JC, Law JD,Cord Stimulation 7. Barolat G, 3 years 22. Kumar K, Hunter G, Demeria D. Spinal Cord Cameron T. Safety and B, A. Epidural with a Multiple Electrode Paddle Lead is relief StimulationLiterature Review. J Neurosurg Spine. Stimulation in Treatment of Chronic Benign Pain: Challenges in Treatment Planning and Present Status, A 20-Year for the Treatment of Chronic Pain: a 22-Year Experience. Neurosurgery. 2006; 58:481-496. 62% had > 50% relief or Effective in Treating Intractable Low Back Pain. 2004;100(3):254-267. 8. Van Buyten JP, Van Zundert J, Vueghs P, Vanduffel L. Up to 59 months Neuromodulation. 2001;4:59-66. Efficacy of Spinal Cord Stimulation: 10 Years of Cameron 747 significantly reduced pain 2. North RB, Kidd DH, Farrokhi F, Piantadosi SA. 9 Experience in a Pain Centre in Belgium. Eur J Pain. (4.9 years) Spinal Cord Stimulation versus Repeated 2001;5:299-307. scores Lumbosacral Spine Surgery for Chronic Pain: A Randomized, Controlled Trail. Neurosurgery. 2005; 56:98-106; discussion 106-107. 35 Reduction in Medication Number of Reference Follow Up Results Patients North2 19 3 years 50% reduced their medications As a group, reduced medication Van Buyten8 123 3 years use by >50% Up to 84 Cameron9 766 45% reduced their medications months Taylor10 681 n/a 53% no longer needed analgesics 2. North RB, Kidd DH, Farrokhi F, Piantadosi SA. Spinal Cord Stimulation 9. Cameron T. Safety and Efficacy of Spinal Cord Stimulation for the versus Repeated Lumbosacral Spine Surgery for Chronic Pain: A Treatment of Chronic Pain: Randomized, Controlled Trail. Neurosurgery. 2005; 56:98-106;iscussion A 20-Year Literature Review. J Neurosurg Spine. 2004;100(3):254-267. 106-107. 10. Taylor RS, Van Buyten JP, Buchser E. Spinal Cord Stimulation for Chronic 8. Van Buyten JP, Van Zundert J, Vueghs P, Vanduffel L. Efficacy of Spinal Back and Leg Pain and Failed Back Surgery Syndrome: A Systematic Cord Stimulation: 10 Years of Experience in a Pain Centre in Belgium. Review and Analysis of Prognostic Factors. Spine. 2005;30:152-160. Eur J Pain. 2001;5:299-307. 36 Improvements in Daily Activities Number of Reference Follow Up Results Patients As a group, significantly improved Barolat7 41 1 years function and mobility As a group, improved in a range North2 19 3 years of activities 7. Barolat G, Oakley JC, Law JD, North RB, Ketcik B, Sharan A. Epidural Spinal 2. North RB, Kidd DH, Farrokhi F, Piantadosi SA. Spinal Cord Stimulation versus Cord Stimulation with a Multiple Electrode Paddle Lead is Effective in Repeated Lumbosacral Spine Surgery for Chronic Pain: A Randomized, Treating Intractable Low Back Pain. Neuromodulation. 2001;4:59-66. Controlled Trail. Neurosurgery. 2005; 56:98-106; discussion 106-107. 37 Return to Work Number of Reference Follow Up Results Patients 31% returned to Van Buyten8 123 3 years work 40% returned to Taylor10 1,133 n/a work 35% returned to Dario11 23 3 years work 8. Van Buyten JP, Van Zundert J, Vueghs P, Vanduffel L. Efficacy of Spinal 10. Taylor RS, Van Buyten JP, Buchser E. Spinal Cord Stimulation for Chronic Cord Stimulation: 10 Years of Experience in a Pain Centre in Belgium. Back and Leg Pain and Failed Back Surgery Syndrome: A Systematic Eur J Pain. 2001;5:299-307. Review and Analysis of Prognostic Factors. Spine. 2005;30:152-160. 11. Dario A, Fortini G, Bertollo D, Bacuzzi A, Grizzetti C, Cuffari S. Treatment of Failed Back Surgery Syndrome. Neuromodulation. 2001;4:105-110. 38 Importance of Timing With SCS in the Treatment of FBSS SCS for patients with FBSS is more effective the sooner an SCS system is implanted from the date of the previous failed surgery. 22. Kumar K, Hunter G, Demeria D. Spinal Cord Stimulation in Treatment of Chronic Benign Pain: Challenges in Treatment Planning and Present Status, a 22-Year Experience. Neurosurgery. 2006; 58:481-496. 39 Chronic Pain • Huge, growing, and expensive problem • Costs are $100 billion annually and growing • 515 million workdays lost • 40 million doctor visits • Estimated number of patients (millions): – Migraine 23 – Cancer and AIDS 8 – Back and neck pain 22 40 Source: Marketdata Enterprises, Inc. Thank you ! Questions?