Spinal Cord Stimulation • There are no disclosures for this presentation Spinal Cord Stimulation (SCS) Jeffrey S. Yablon M.D. Clinical Associate Professor of Neurological Surgery UCSF Medical Director Peggy Herman Center for the Neurosciences June 1, 2013 2 Pain is a Significant Issue Healthcare Costs • Workers’ Compensation costs have increased • #1 Admitting diagnosis in US dramatically in recent years – From 1970-1990, premiums paid by employers in the US increased from $4.9 billion to $53.1 billion • #1 Reason for missed work in US – The number of people in the workforce only increased from 59-95 million • Chronic pain costs the US $100B / year in direct medical costs, lost income and productivity 3 4
Healthcare Costs Chronic Pain Chronic pain is continuous pain that persists for • With Medical costs increasing at the rates • more than 3 months, and beyond the time of normal they are for the treatment of low back pain, healing. It ranges from mild to severe and can last it is imperative that patients get the care weeks, months, or years to a lifetime. (http://www.niams.nih.gov) they need as early as possible 20% of the population in developed countries is • • Earlier intervention leads to better care and afflicted with chronic pain better outcomes – 30-40% due to musculoskeletal and joint disorders – 30% neck and back pain – Headache and migraines < 10% Pain Clinical Updates, Sep. 2004, IASP Pain Clinical Updates, Sep. 2004, IASP 5 6 Neuropathic Pain Neuropathic Pain • 4M People in the US/year suffer from • Treatment often fails because 1 : Neuropathic pain (NP), caused by a primary • Inadequate diagnosis and a lack of appreciation of lesion or dysfunction in the nervous the mechanisms involved system 1 • Insufficient management of comorbid conditions • Associated with diabetic peripheral • Incorrect understanding or selection of treatment neuropathy, post herpetic neuralgia, human options immunodeficiency virus-related disorders, and chronic radiculopathy. 1 J Pain Symptom Manage. 2003 May;25 (5Suppl):S12-7 7 8
Chronic Neuropathic Pain Therapeutic Options � Chronic, intractable, neuropathic pain is intense pain • Management of chronic pain includes a variety of caused by injury to the nervous system that lasts techniques. Conservative, or noninvasive, treatments several months or longer and is not relieved by are tried first; if these do not work, invasive, or medical and/or surgical care. advanced, techniques may be used. It can result from an injury long since healed or from � an ongoing condition such as nerve damage, cancer, or chronic infections. Common causes include Failed Back Syndrome � (FBSS), Arachnoiditis, Complex Regional Pain Syndrome (CRPS), Radiculopathies, and Peripheral Neuropathy of Upper and Lower Extremity Nerves (Upper-Ulnar, Median, Radial. Lower–Tibial and Common Peroneal). 9 10 Selection Criteria for SCS Mechanism of SCS • Psychiatric and psychological assessment • Generates electric field in epidural space • Evidence that psychiatric opinion is • Stimulates axons of effective in identifying poor risk candidates. dorsal column (primarily) Nielsen et al. Surg Neurol, 1975 and dorsal root fibers in • In Belgium, where reimbursement for SCS is spinal column conditional upon psych assessment, • Produces a pleasant success rate was 3X higher in those paresthesia. approved by psychiatrist in a series of 100 • Need maximal control patients, Kupers et al. 1994 over stimulation of the targeted nerves, while • Quality of the pain is important. preventing stimulation of undesired neurons. • Continuous burning, sharp. Other neuropathic pain descriptors. • Not effective against nociceptive pain such as cancer pain, arthritis, wound pain, etc. 11 12
Current Indications Failed Back Surgery Syndrome • $20B annually in direct health care costs 1 “Indicated as an aid in the management of chronic intractable pain of the trunk and/or limbs, including unilateral or bilateral pain associated • 5 th most common reason for MD visit 1 with the following: Failed Back Surgery Syndrome, intractable low back pain and leg pain.” • Patient continues to experience chronic back and/or leg pain despite surgery. The most common reason for FBSS is poor patient selection (psychological, social, behavioral issues) Commonly treated syndromes (approved when lead is placed in the epidural space) • Common Psychosocial disorders in FBSS • CRPS 1 & 2 • Depression, Anxiety, Somatization, Personality disorders, and secondary gain issues • Arachnoiditis • Strong evidence supports that low back pain is neuropathic • Post Thoracotomy Pain • Peripheral Neuropathy • Important to identify and treat other etiologies of FBSS that • Post Herpetic Neuralgia are not neuropathic and not candidates for SCS • Phantom Limb Pain • Foraminal stenonsis, descogenic pain, recurrent disc herniation, • Ilioinguinal Neuralgia pseudoarthrosis, facetogenic pain, sacroiliac syndrome 13 14 Chronic Postamputation Pain Studies of Clinical Effectiveness • Two Possible Neuropathic syndromes Early study Conclusions re: SCS: • Pain in the stump which is related to neuroma formation following SCS was significantly more successful than reoperation in giving selected FBSS patients • the sectioning of the sciatic nerve at least 50% pain relief. * • Pain is felt in the amputated extremity and is termed Phantom Pain Lower morbidity than surgery and opportunity for therapeutic trial are important • advantages. * • SCS therapy is typically not the first line choice for pain Computerized system optimized pain relief better, more than doubled battery life, and • reduced costs by about one-third. ** control Battery life is a major SCS cost driver. If it can be prolonged, lifetime savings can exceed • $300,000 for average patient. ** • SCS was less expensive and more effective than reoperation in selected failed back- surgery syndrome patients, and should be the initial therapy of choice. SCS is most Post Thoracotomy Syndrome cost-effective when patients forego repeat operation. Should SCS fail, reoperation is unlikely to succeed. 6-month outcomes demonstrate significant improvements of SCS patients compared to • CMM group -Significantly more SCS patients (48% versus 9%) achieved the primary • Chronic chest wall pain syndromes that follow a outcome of ≥ 50% pain relief (p<0.001). thoracotomy and sternotomy • The pain is due to injury to at least one intercostal nerve 15 16
Studies of SCS Effectiveness Summary • Chronic pain is a pervasive, expensive problem for society, Study Outcome government, employers, payers, and individuals. • Kemler & Furnee 2002 • CRPS – Pain but not • SCS has been proven effective for chronic neuropathic pain in functional status or many studies over decades, including recent RCTs. depression improved compared with PT • Present generation devices have overcome the technical problems and high failure rates common in early devices. • Kumar 2002 • FBS – SCS group improved 15% > non • Routine trial stimulation, better patient selection criteria, and improved understanding of appropriate indications insure SCS group that SCS is only performed in those who have a high likelihood of benefit. • Significant improvement • Alo 2002 in pain. 8/10 prior to • Cost analyses have repeatedly shown that SCS saves surgery to 4.9/10 4 years money when used appropriately. post surgery. 17 18 Trial Stimulation: SCS System Types Temporary Percutaneous Lead • Conventional SCS Technologies Preferred test • • Radio Frequency stimulation – Requires patient to wear external equipment to power for surgical the implant paddle leads • Fully implantable, Primary Cell battery Lead implanted – Short life span and repeat replacement surgeries • and secured to skin • Advanced SCS Technology • Fully implantable, rechargeable power Allows for test • – Long lasting stimulation – Significantly smaller implant of several days – Increased stimulation parameters and therapy options 19 20
Permanent Trial Permanent Implant • Begin same method as • More invasive trial trial option • Remove extension • Why use permanent from permanent trial trial technique? • Remove splitter challenging lead – • Using fluoro of trial lead as placement reference for place permanent physician – leads preference • Advantages vs. disadvantages 21 22 Surgical Lead Implantation • Surgical lead choice Surgical Lead Implantation • Procedure – Laminotomy – Surgical lead placement • Advantages vs. disadvantages 23 24
Success of Spinal Cord Stimulation Assure lead stability • Common Surgical SCS Review instructions with patient’s family • Complications Ensure patient’s full understanding of system operation • & How to Avoid Them Successful stimulation demands topographic coverage of the • electrical field of paresthesia over the area of the pain 25 26 #1 SCS Complication Lead Migration Prevention • Insert long length of lead in epidural space • Anchor securely to fascia / supraspinous ligament Lead migration is • Hard copies of intra-op fluoro cited as the #1 complication. • Limit physical activity for at least 2 weeks – No lifting objects > 5 lbs – No twisting, bending, or climbing – Do not raise arms above head 27 28
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