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					    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.
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