Spinal Cord Stimulation for theTreatment of Chronic Pain
John Talley Parrot, MD
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
Disclosure Slide
Just So I Didn’t Forget My Questions Doctor Parrott
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, 19848.Deyo RA, Tsui-Wu Y-J: Descriptive Epidemiology of low back pain and its related medical care in the United States. Spine 12; 264-268, 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; 22:263-71.)
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.)
Chronic Pain
725k lumbar fusions/discectomies 2000(Agency for Healthcare Research and Quality. Healthcare Cost & Utilization Project (HCUP). Accessed May 10, 2007, athttp://www.ahrq.gov/data/hcup/)
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. )
Chronic Pain
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.
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.
“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)
Epidemiology
Slipman CW. Etiologies of Failed Back Surgery Syndrome, Pain Medicine 2002;3(3):200-214
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
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
Neuropathic Radicular Pain
http://www.netterimages.com/image/list.htm?page=2&s=spinal%20cord; image 1317)
Mixed Pain
Many patients have a combination of both nociceptive and neuropathic pain
Disease or trauma has damaged both nerve cells and other tissues
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
What is Spinal Cord Stimulation?
Diagnosis
First Tier
Second-Tier
Third Tier
Physical TherapyNSAIDSAnalgesics
NeurostimulationSurgical Intervention
Diagnostic blocksTherapuetic proc.s
ImagingEMG/NCS
Therapeutic Algorithm
Neuromodulation Devices
Allow the delivery of very small, precise doses of electricity
or drugs directly to targeted nerve sites.
Precise delivery of small doses of electricity directly to targeted nerve sites
Neuromodulation DevicesElectrical Stimulators
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.
CNS Pain Management (Theory) Gate Control Theory Melzack and Wall, 1968
C FIBER
PROJECTION NEURONAaAb FIBERS
INHIBITORYINTERNEURON
C FIBER
PROJECTION NEURONAaAb FIBERS
INHIBITORYINTERNEURON
Gate Control Theory
Pain
Sensory
When sensory impulses are greater than pain impulses “Gate” in the spinal cord closes preventing the pain signal
from reaching the brain
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 NEURONAaAb FIBERS
INHIBITORYINTERNEURON
Pain
Sensory
Gate
SCS
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
Advantages of SCS Therapy Safe Testable ** Non-destructive Mostly reversible Long-term cost is low
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
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
© 2010 St. Jude Medical, Inc. All rights reserved.
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
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
How Are Clinical Factors Evaluated?
Patient Selection Process Correctly diagnosed Failed lower level therapies Successfully passed psyche evaluation Patient is motivated Patient is educated
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)
SCS Phases
Trial Permanent implant
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.
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.
Trial System
Trial Lead
Trial Cable
Trial Generator/
Programmer
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
The Patient’s Role in TrialsThe 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
Patient/Device Criteria
Conventional IPG Rechargeable IPG
Power requirements Low to moderate Moderate to high
Frequency requirements
Low Low to moderate
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
Single Or Dual Trial Leads
Paddle Lead Arrays
Tripolar Paddle Array Penta Five Column Array
SCS StudiesReduction in painAuthor 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 3 years 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;58:481-496.
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;132:179-188.
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;5:299-307.
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):254-267.
SCS StudiesReduction in medicationAuthor No. Patients Follow-Up Results
North 19 3 years 50% reduced their med use
Van Buyten 123 3 years >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;132:179-188.
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;5:299-307.
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):254-267.
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;30:152-160.
SCS StudiesImprovement in daily activitiesAuthor 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;132:179-188.
SCS StudiesReturn to workAuthor 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 3 years 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;5:299-307.
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;30:152-160.
Dario A, Fortini G, Bertollo D, Bacuzzi A, Grizzetti C, Cuffari S. Treatment of Failed Back Surgery Syndrome. Neuromodulation. 2001;4:105-110.
Questions?