1. Spinal Cord Stimulation for the Treatment of Chronic Pain
John Talley Parrot, MD

2. I am a faculty consultant for Medtronics and Synthes / AO Spine
Disclosure Slide
I have no financial relationships with any commercial interest related to the content of this activity
I am a faculty consultant for Medtronics and Synthes / AO Spine
So, effective treatment of chronic LBP is critical and hinges on an accurate diagnosis. For no treatment option will be effective if it is targeting the wrong structure.

3. Just So I Didn’t Forget My Questions Doctor Parrott

4. Chronic Pain Lifetime prevalence > 70%
(Damkot DK, Pope MH, Lord J, Frymoyer JW.The relationship between work history, work environment and low back pain in men. Spine 9:395, 1984.)
US 1 year prevalence rate—5-20%
(Cunningham LS, Kelsey JL: Epidemiology of musculoskeletal impairments and associated disability. Am J Public Health. 74:574, Deyo RA, Tsui-Wu Y-J: Descriptive Epidemiology of low back pain and its related medical care in the United States. Spine 12; , 1987.)
Annual direct medical costs $25 billion
(Frymoyer JW, Cats-Baril WL. An overview of incidences and costs of low back pain. Orthop Clin North America 1991; 22: )
Most common cause of disability < 45 y/o
2.4 million disabled
Return To Work = 0 after 2 yr absence d/t LBP
(Bigos SJ, Bettie MC: The impact of spinal disorders in industry. The Adult Spine. New York, Raven Press, 1991.)
So, effective treatment of chronic LBP is critical and hinges on an accurate diagnosis. For no treatment option will be effective if it is targeting the wrong structure.

5. Chronic Pain 725k lumbar fusions/discectomies 2000
(Agency for Healthcare Research and Quality. Healthcare Cost & Utilization Project (HCUP). Accessed May 10, 2007, at
30k-40k lumbar laminectomy patients/yr obtain no relief or recurrence of symptoms
(Keane GP. Failed low back surgery syndrome. In: Cole AJ, ed. The low back pain handbook. Phila- delphia: Mosby; 1997:269–81. )
So, effective treatment of chronic LBP is critical and hinges on an accurate diagnosis. For no treatment option will be effective if it is targeting the wrong structure.

6. Long-Term Pain Affects Most of Your Patients
3 out of 4 Americans have experienced chronic or recurring pain or have a family member who has experienced such pain
Almost 62% of pain sufferers have had their pain for a year or more
A majority of adults (57%) have experienced chronic or recurring pain, including 54% of adults aged 18–34
Reference: Americans Talk about Pain, conducted by Peter D. Hart Research Associates for Research!America, August 2003.

7. Millions of Americans Suffer With Pain…
50 million Americans are partially or totally disabled by chronic pain
9 out of 10 Americans (aged 18 and older) suffer with pain at least once a month
77% of pain patients strongly agree that new options are needed to treat their pain
50% of Americans (aged 65 and older) suffer daily pain
Reference: Pain in America: A Research Report, conducted by the Gallup Organization for Merck, June 1999.

8. Epidemiology “Failed Back Surgery Syndrome”
Heterogenous group of disorders
Specific diagnosis neither implicit or explicit
Multiple possible explanations
Persistent/recurrent/new LBP or lower limb pain
Multiple etiologies
(Slipman - Pain Med 2002, Schoferman -Pain Med 2002, Bernard - Spine 1993, Long J. - NS 1988)
So, effective treatment of chronic LBP is critical and hinges on an accurate diagnosis. For no treatment option will be effective if it is targeting the wrong structure.

9. It’s imperative that the treating spine specialists clearly understand and recognize surgical vs nonsurgical etiologies for recurrent radicular pain after lumbosacral surgery. Proper treatment of the former after conservative measures fail must include surgical intervention in order to optimize treatment outcomes. Non-surgical etiologies containing stable surgical constructs represent conditions which may be sufficiently addressed with non-surgical treatment options including SCS.
Slipman CW. Etiologies of Failed Back Surgery Syndrome, Pain Medicine 2002;3(3):

10. 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
Obstructive

11. Neuropathic Pain
Abnormal processing of sensory input by the peripheral or central nervous system
Centrally generated pain
Peripherally generated pain
Dorsal Root Ganglion (DRG)
Nerve Root

12. Neuropathic Radicular Pain
image 1317)

13. Mixed Pain
Many patients have a combination of both nociceptive and neuropathic pain
Disease or trauma has damaged both nerve cells and other tissues

14. History of Neurostimulation
One of the earliest uses of electricity in medicine was for pain relief.
Around 15 A.D., Scribonius reported that a torpedo fish could be used to apply an electrical charge to patients to relieve pain.
Reference: Gildenberg PL. History of electrical neuromodulation for chronic pain. Pain Medicine. 2006;7(S1):S7-S13

15. What is Spinal Cord Stimulation?

16. Therapeutic Algorithm
Third Tier
Second-Tier
Neurostimulation
Surgical Intervention
First Tier
Diagnostic blocks
Therapuetic proc.s
Diagnosis
Physical Therapy
NSAIDS
Analgesics
Imaging
EMG/NCS

17. Neuromodulation Devices
Allow the delivery of very small, precise doses of electricity
or drugs directly to targeted nerve sites.

18. Neuromodulation Devices Electrical Stimulators
Precise delivery of small doses of electricity directly to targeted nerve sites

19. 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.

20. CNS Pain Management (Theory)
Gate Control Theory
Melzack and Wall, 1968
C FIBER
PROJECTION NEURON
AaAb FIBERS
INHIBITORY INTERNEURON

21. INHIBITORY INTERNEURON
Gate Control Theory
When sensory impulses are greater than pain impulses
“Gate” in the spinal cord closes preventing the pain signal from reaching the brain
C FIBER
PROJECTION NEURON
AaAb FIBERS
INHIBITORY INTERNEURON
Sensory
Pain

22. INHIBITORY INTERNEURON
Gate Theory and SCS
SCS system implanted near dorsal column stimulates the pain-inhibiting nerve fibers masking painful sensation with a tingling sensation (paresthesia)
C FIBER
PROJECTION NEURON
AaAb FIBERS
INHIBITORY INTERNEURON
Sensory
SCS
Gate
Pain

23. Tenets of SCS Comprehensive trial Customizable system components
Optimized efficiency in programs and design
Team approach to patient care
Anesthesia Pain Physician
Orthopedic Spine / Neurosurgeon
SCS Medical Device Clinical Representatives

24. Advantages of SCS Therapy
Safe
Testable **
Non-destructive
Mostly reversible
Long-term cost is low

25. Disadvantages of SCS Therapy
Refractory on some patients
Potential equipment failure
Short-term costs can be high, but are reimburseable via Medicare, workers compensation, and the private payer community
Long term follow-up required via anesthesia pain management, and / or SCS medical device clinical representation
Steep learning curve for procedure

26. 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 maximum effectiveness, patient comfort, and energy efficiency
Reduce medication, restore function and improve quality of life
Return patient to work

27. Factors Influencing Therapy Success
Clinical
Indications
Pain etiology
Pain distribution
Patient factors
SCS Device
Sufficient coverage
Targeting of electrical field
Sustainability of therapy 27
© 2010 St. Jude Medical, Inc. All rights reserved.

28. Clinical Factors Indication Responsive to SCS Disease Etiology
Disease 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

29. 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

30. How Are Clinical Factors Evaluated?
Patient Selection Process
Correctly diagnosed
Failed lower level therapies
Successfully passed psyche evaluation
Patient is motivated
Patient is educated

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 (Rechargeable Or Conventional)

32. SCS Phases
Trial
Permanent implant

33. Trials
One advantage of SCS over the other pain management or surgical therapies is that it can be tested on patients before an SCS device is permanently implanted.
The trial gives the implanting physician important information for determining which of the three SCS systems is appropriate for a specific patient.

34. Trials A spinal cord stimulation trial involves
A short outpatient procedure during which the implanting physician places one or more leads in the space over the spinal cord.
The patient is awake during the procedure so that he or she can provide feedback to the physician regarding exact placement.
The lead connects to a device that can be worn on a belt. The device may contain a variety of programs.

35. Trial System
Trial Lead
Trial Cable
Trial Generator/
Programmer

36. Length of Trials
Trial length determined by daily verbal patient verbal
Anesthesia pain physician staff – daily telephone calls
SCS clinical representatives – daily telephone calls and office visit for adjustment intra-trial if needed
Short-term trials
2 to 5 days
Long-term trials
5 to 7 days

37. The Patient’s Role in Trials
The patient should:
Have a working knowledge of the SCS trial device
Understand movement restrictions
Reduce bending at the waist
Reduce lifting over the head
Understand the sensations to be expected
Be able to document his or her responses, pain level, and functional changes
Be reasonably active

38. Patient/Device Criteria
Conventional IPG
Rechargeable IPG
Power requirements
Low to moderate
Moderate to high
Frequency requirements
Low
Pain
Stable
Likely to progress
Coverage needs
(contacts/leads)
8 contacts on
1 or 2 leads
8 or 16 contacts on
1-4 leads
Compliance
(motivation and ability)
Requires very little
interaction
High—due to
recharging protocol
Competence
(physical or mental)
Appropriate for all levels
Higher level required
Skin sensitivity
Patients with high
sensitivity
Patients with moderate
to low sensitivity
Implant size
Moderate to large sizes
Small to moderate size
Implant longevity
2-7 years
5-10 years
Patient interface
Easier to use
Requires management

39. Single Or Dual Trial Leads

40. Paddle Lead Arrays
Tripolar Paddle Array
Penta Five Column Array

41. SCS Studies Reduction in pain Author No. Patients Follow-Up Results
Kumar
410
8 years
74% had ≥ 50% relief
North 19
3 years
47% had ≥ 50% relief
Barolat 41
1 year
50%-65% had good/excel. relief
Van Buyten
123
68% had good/excel. relief
Cameron
747
up to 59 mos.
62% had ≥ 50% relief or significant reduction in pain scores
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:
North RB,Kidd DH, Farrokhi F,Piantadosi SA. Spinal Cord Stimulation versus Repeated Lumbosacral Spine Surgery for Chronic Pain: a Randomized Controlled Trial in Patients with Failed Back Surgery Syndrome. Pain.2007;132:
Barolat G, Oakley JC, Law JD, North RB, Ketick B, Sharan A. Epidural Spinal Cord Stimulation with a Multiple Electrode Paddle Lead is Effective in Treating Intractable Low Back Pain. Neuromodulation. 2001;4:59-66.
Van Buyten JP,Van Zundert J,Vueghs P, Vanduffel L. Efficacy of Spinal Cord Stimulation : 10 Years of Experience in a Pain Centre in Belgium. Eur J Pain. 2001;5:
Cameron T. Safety and Efficacy of Spinal Cord Stimulation for the Treatment of Chronic Pain: A 20-Year Literature Review. J Neurosurg Spine. 2004;100(3):

42. SCS Studies Reduction in medication Author No. Patients Follow-Up
Results
North 19
3 years
50% reduced their med use
Van Buyten
123
>50%reduction in med use
Cameron
766
up to 84 mos.
45% reduced their med use
Taylor
681
n/a
53% no longer needed Analgesics
North RB,Kidd DH, Farrokhi F,Piantadosi SA. Spinal Cord Stimulation versus Repeated Lumbosacral Spine Surgery for Chronic Pain: a Randomized Controlled Trial in Patients with Failed Back Surgery Syndrome. Pain.2007;132:
Van Buyten JP,Van Zundert J,Vueghs P, Vanduffel L. Efficacy of Spinal Cord Stimulation : 10 Years of Experience in a Pain Centre in Belgium. Eur J Pain. 2001;5:
Cameron T. Safety and Efficacy of Spinal Cord Stimulation for the Treatment of Chronic Pain: A 20-Year Literature Review. J Neurosurg Spine. 2004;100(3):
Taylor RS, Van Buyten JP, Buchser E. Spinal Cord Stimulation for Chronic Back and Leg Pain and Failed Back Surgery Syndrome: A Systematic Review and Analysis of Prognostic Factors. Spine. 2005;30:

43. SCS Studies Improvement in daily activities Author No. Patients
Follow-Up
Results
Barolat 41
1 year
As a group, significant improvements in
function and mobility
North 19
3 years
As a group, improvements in a range of
activities
Barolat G, Oakley JC, Law JD, North RB, Ketick B, Sharan A. Epidural Spinal Cord Stimulation with a Multiple Electrode Paddle Lead is Effective in Treating Intractable Low Back Pain. Neuromodulation. 2001;4:59-66.
North RB,Kidd DH, Farrokhi F,Piantadosi SA. Spinal Cord Stimulation versus Repeated Lumbosacral Spine Surgery for Chronic Pain: a Randomized Controlled Trial in Patients with Failed Back Surgery Syndrome. Pain.2007;132:

44. SCS Studies Return to work Author No. Patients Follow-Up Results
Van Buyten
123
3 years
31% returned to work
Taylor
1,133
n/a
40% returned to work
Dario 23
35% returned to work
Van Buyten JP,Van Zundert J,Vueghs P, Vanduffel L. Efficacy of Spinal Cord Stimulation : 10 Years of Experience in a Pain Centre in Belgium. Eur J Pain. 2001;5:
Taylor RS, Van Buyten JP, Buchser E. Spinal Cord Stimulation for Chronic Back and Leg Pain and Failed Back Surgery Syndrome: A Systematic Review and Analysis of Prognostic Factors. Spine. 2005;30:
Dario A, Fortini G, Bertollo D, Bacuzzi A, Grizzetti C, Cuffari S. Treatment of Failed Back Surgery Syndrome. Neuromodulation. 2001;4:

45. Questions?