Neurostimulation

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Neurostimulation

• For Complex Regional Pain Syndrome Literature
  Review Summary

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Background

• The second most common use of spinal cord
  stimulation (SCS) in the United States is for the
  symptomatic management of complex regional pain
  syndrome (CRPS).
• CRPS is a neuropathic pain syndrome precipitated
  most commonly by minor limb trauma.1,2,3,4
• Continuous, severe pain, disproportionate to the
  inciting event, occurs in the limb and may be
  accompanied by allodynia, hyperalgesia, skin
  color changes, edema, joint stiffness, and bone
  demineralization.1,4,5
• This literature review summary highlights results
  of studies to demonstrate the clinical and
  cost-effectiveness of SCS for CRPS.

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Effectiveness StudyKemler MA, et al. 20006, 20047

• Prospective, randomized, controlled study of 54
  type I CRPS patients randomized to receive SCS
  plus PT or PT alone.
• At the 2-year follow-up, pain intensity in the
  SCS group had decreased by a mean of 3.0 cm on
  the VAS, vs. 0 cm for PT-only patients (P lt
  0.001).
• At 24 months, global perceived effect (GPE) was
  much improved in 63 of SCS patients vs. 9 of
  PT-only patients (P lt 0.001).
• At 24 months, as compared to PT-only patients,
  SCS patients had significant improvement in
  health-related quality of life (HRQoL) (P 0.02
  affected hand, P 0.008 foot).

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Effectiveness StudyHarke H, et al. 20054

• Prospective study of 29 patients with type I
  CRPS.
• At 12 months after implant, deep pain and
  allodynia on the VAS were reduced from a mean of
  10 cm to 1.7 cm and from a mean of 10 cm to 0.03
  cm, respectively (P lt 0.01).
• Disability scores decreased gt 50 (P lt 0.01).
• At a mean follow-up of 35 months, 59 of patients
  did not require analgesics and 70 had returned
  to work.

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Effectiveness StudiesForouzanfar T, et al. 20045

• Prospective study of 36 type I CRPS patients.
• At 24 months HRQoL (EQ-5D) significantly
  improved (P lt 0.02). The number of patients
  reporting extreme problems for the categories
  usual activities and pain and discomfort
  decreased for both cervical (Figure A) and lumbar
  (Figure B) patients (P lt 0.01). The percent of
  patients reporting no problems in the
  anxiety/depression dimension increased (P lt
  0.02).

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Effectiveness StudiesBennett DS, et al. 19998

• Retrospective, multicenter study of 101 CRPS
  patients.
• The mean improvement in VAS was 6.0 cm for
  patients with dual-octapolar systems and 3.70 cm
  for patients with single-lead quadripolar systems
  (P lt 0.0001).
• Overall patient satisfaction scores were 70 in
  single-lead patients at 18.7 months mean
  follow-up and 91 in dual-octapolar patients at
  23.5 months mean follow-up (P lt 0.05).

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Effectiveness StudyKemler MA, et al. 19999

• Retrospective study of 23 consecutive patients
  with type I CRPS (n 18 implanted).
• At a mean follow-up of 32 months, mean VAS for
  implanted patients had improved from 7.9 cm to
  5.4 cm (P lt 0.001).
• 87 of patients reported a Global Perceived
  Effect (GPE) of much improved or improved and
  therapy was regarded as a success.

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Cost StudyKemler MA, et al. 200210

• Calculated health care costs (1998 Euros) for 54
  CRPS patients randomized to SCS plus physical
  therapy (PT) or PT alone.
• Costs shown for SCS implanted patients are minus
  the cost of PT.

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Cost StudyKumar K, et al. 200611
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Summary

• The referenced effectiveness studies4,5,7,8,9
  found that at long-term follow-up, SCS provided
  significant pain relief and has been associated
  with substantial long-term success as measured by
  global perceived effect.5,7,9
• One study demonstrated that SCS led to a
  reduction in medication use.4 Two studies have
  shown improvements in function and daily
  living4,9, and enabled patients to return to
  work.4
• The referenced cost studies show that mean
  first-year cost of SCS became substantially less
  in the second year. This was also found in three
  studies of SCS for FBSS.12,13,14
• SCS has become increasingly successful due to
  refined patient selection criteria, greater
  accuracy in electrode placement, and improvement
  in multipolar and multichannel systems.1 However,
  complications still occur. The most frequent
  complication of SCS system implantation has been
  electrode migration.5,7,8,9 Various complications
  have also led to surgical revision of the pulse
  generator, lead and/or system explantation.5,7,9

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Conclusions

• The referenced long-term clinical studies have
  shown that SCS provides statistically significant
  pain relief in patients with CRPS.
• Despite a high cost the first year, SCS has been
  shown to be more effective and less expensive
  than conventional treatment in the long term.

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Neurostimulation Therapy for Chronic PainTruck
and/or Limbs Product manuals must be reviewed
prior to use for detailed disclosure.
Indications Implantable neurostimulation
systems A Medtronic implantable neurostimulation
system is indicated for spinal cord stimulation
(SCS) system as an aid in the management of
chronic, intractable pain of the trunk and/or
limbsincluding unilateral or bilateral pain
associated with the following conditions Failed
Back Syndrome (FBS) or low back syndrome or
failed back, radicular pain syndrome or
radiculopathies resulting in pain secondary to
FBS or herniated disk, postlaminectomy pain,
multiple back operations, unsuccessful disk
surgery, degenerative Disk Disease
(DDD)/herniated disk pain refractory to
conservative and surgical interventions,
peripheral causalgia, epidural fibrosis,
arachnoiditis or lumbar adhesive arachnoiditis,
Complex Regional Pain Syndrome (CRPS), Reflex
Sympathetic Dystrophy (RSD), or
causalgia. Contraindications Diathermy Do not
use shortwave diathermy, microwave or therapeutic
ultrasound diathermy (all now referred to as
diathermy) on patients implanted with a
neurostimulation system. Energy from diathermy
can be transferred through the implanted system
and cause tissue damage at the locations of the
implanted electrodes, resulting in severe injury
or death. Warnings Sources of strong
electromagnetic interference (e.g.,
defibrillation, diathermy, electrocautery, MRI,
RF ablation, and therapeutic ultrasound) can
interact with the neurostimulation system,
resulting in serious patient injury or death.
These and other sources of EMI can also result in
system damage, operational changes to the
neurostimulator or unexpected changes in
stimulation. Rupture or piercing of the
neurostimulator can result in severe burns. An
implanted cardiac device (e.g., pacemaker,
defibrillator) may damage a neurostimulator, and
the electrical pulses from the neurostimulator
may result in an inappropriate response of the
cardiac device. Precautions The safety and
effectiveness of this therapy has not been
established for pediatric use (patients under the
age of 18), pregnancy, unborn fetus, or delivery.
Patients should be detoxified from narcotics
prior to lead placement. Clinicians and patients
should follow programming guidelines and
precautions provided in product manuals. Patients
should avoid activities that may put undue stress
on the implanted neurostimulation system
components. Patients should not scuba dive below
10 meters of water or enter hyperbaric chambers
above 2.0 atmosphere absolute (ATA).
Electromagnetic interference, postural changes,
and other activities may cause shocking or
jolting. Adverse Events Adverse events may
include undesirable change in stimulation
described by some patients as uncomfortable,
jolting or shocking hematoma, epidural
hemorrhage, paralysis, seroma, CSF leakage,
infection, erosion, allergic response, hardware
malfunction or migration, pain at implant site,
loss of pain relief, chest wall stimulation, and
surgical risks. For further information, please
call Medtronic at 1-800-328-0810 and/or consult
Medtronics website at www.medtronic.com. Rx only
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References

• 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.
  200658481-496.
• Merskey H, Bogduk N. Classification of Chronic
  Pain Descriptions of Chronic Pain Syndromes and
  Definitions of Pain Terms. Seattle, WA IASP
  Press 1994.
• Baron R, Levine JD, Fields HL. Causalgia and
  reflex sympathetic dystrophy does the
  sympathetic nervous system contribute to the
  generation of pain? Muscle Nerve.
  199922678-695.
• Harke H, Gretenkort P, Ladleif HU, Rahman S.
  Spinal cord stimulation in sympathetically
  maintained complex regional pain syndrome type I
  with severe disability. A prospective clinical
  study. Eur J Pain. 20059363-373.
• Forouzanfar T, Kemler MA, Weber WEJ, et al.
  Spinal cord stimulation in complex regional pain
  syndrome cervical and lumbar devices are
  comparably effective. Br J Anaesth.
  200492349-353.
• Kemler MA, Barendse GAM, Van Kleef M, et al.
  Spinal cord stimulation in patients with chronic
  reflex sympathetic dystrophy. N Engl J Med.
  2000343618-624.
• Kemler MA, de Vet HCW, Barendse GAM, et al. The
  effect of spinal cord stimulation in patients
  with chronic reflex sympathetic dystrophy two
  years follow-up of the randomized controlled
  trial. Ann Neurol. 20045513-18.
• Bennett DS, Aló KM, Oakley J, Feler CA. Spinal
  cord stimulation for complex regional pain
  syndrome RSD a retrospective multicenter
  experience from 1995 to 1998 of 101 patients.
  Neuromodulation. 19992201-210.
• Kemler MA, Barendse GAM, Van Kleef M, et al.
  Electrical spinal cord stimulation in reflex
  sympathetic dystrophy retrospective analysis of
  23 patients. J Neurosurg. 19999079-83.
• Kemler MA, Furnée CA. Economic evaluation of
  spinal cord stimulation for chronic reflex
  sympathetic dystrophy. Neurology.
  2002591203-1209.
• Kumar K, Wilson JR, Taylor RS, Gupta S.
  Complications of spinal cord stimulation,
  suggestions to improve outcome, and financial
  impact. J Neurosurg Spine. 20065191-203.
• Taylor RJ, Taylor, RS. Spinal cord stimulation
  for failed back surgery syndrome a
  decision-analytic model and cost-effective
  analysis. Int J Technol Assess Health Care.
  200521351-358.
• Bell GK, Kidd D, North RB. Cost-effective
  analysis of spinal cord stimulation in treatment
  of failed back surgery syndrome. J Pain Symptom
  Manage. 199713286-295.
• Kumar K, Malik S, Demeria D, et al. Treatment of
  chronic pain with spinal cord stimulation versus
  alternative therapies cost-effectiveness
  analysis. Neurosurgery. 200251106-116.

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Thank you
200805142a EN