Neurostimulation

1
Neurostimulation

• For Failed Back Surgery Syndrome Literature
  Review Summary

2
Background

• The most common use of SCS in the United States
  is for controlling the pain associated with
  failed back surgery syndrome (FBSS).
• FBSS occurs in patients who have typically
  undergone multiple lumbosacral spine operations
  for conditions such as disk herniation, lumbar
  stenosis, or spinal instability.1,2,3,4
• The majority of patients with FBSS have radicular
  pain in one or both legs, and many patients also
  have axial lower back pain.2
• This literature review summary highlights results
  of studies to demonstrate the clinical and
  cost-effectiveness of SCS for FBSS.

3
Effectiveness StudyKumar K, et al. 20071
Figure 1

• Prospective, randomized, controlled multicenter
  study of 100 FBSS patients randomized to
  conventional medical management (CMM) with or
  without SCS.
• At 6 months, 48 (24/50) of SCS patients and 9
  (4/43) of CMM patients achieved the primary
  outcome of 50 leg pain relief.
• SCS group had significantly greater
  health-related quality of life (HRQoL) (P lt
  0.02) (Figure 1) and functional capacity (P lt
  0.001) (Figure 2).
• At 12 months, as-treated analysis found that 48
  of SCS patients and 18 of CMM patients achieved
  50 leg pain relief (P 0.03).

Figure 2
4
Effectiveness StudyNorth RB, et al. 20055

• Prospective, randomized, controlled study of 50
  FBSS patients who had been selected for repeat
  lumbosacral spine surgery. Patients were
  randomized to SCS or re-operation.
• At a mean follow-up of 2.9 years, 47 of SCS
  patients and 12 of re-operation patients
  reported 50 pain relief and satisfaction with
  treatment (P lt 0.01).
• Use of narcotics was significantly less in SCS
  patients, in that use was stable or decreased in
  87 compared to 58 in re-operation patients (P lt
  0.025).

5
Effectiveness StudiesKumar K, et al. 20066 and
Leveque J-C, et al. 20016

• Retrospective study of 410 SCS patients, of which
  220 were FBSS patients. At a mean follow-up
  period of 97.6 months, 60 (132/184) of implanted
  patients had 50 pain relief.2
• Retrospective study of 30 FBSS patients 16 had
  permanent SCS system implantation. At a median
  follow-up of 34 months, 75 (12/16) of implanted
  patients said that they were continuing to
  experience 50 pain relief.6

6
Effectiveness StudiesDario A, et al. 20017 and
Ohnmeiss DD, et al. 20018

• Prospective study of 49 FBSS patients, of which
  24 were SCS candidates. At a mean follow-up of 42
  months, 91 (21/23) of implanted patients
  continued to have good results.7
• Retrospective study of 41 consecutive SCS
  candidates with chronic, intractable low back
  pain (mainly FBSS). At follow-up, which ranged
  from 5.5 to 19 months, 70 (21/36) of implanted
  patients said they were satisfied with SCS
  outcome, 76 said they would have SCS again, and
  79 said they would recommend SCS to someone
  else.8

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Additional Effectiveness Studies
8
Cost StudyNorth RB, et al. 200713

• Hospital and professional charge data (1991-1995
  US) on 40/50 patients in the randomized trial of
  the effectiveness of SCS vs. re-operation.5
• Mean cost per patient for intention to treat
  (ITT) was 31,530 for SCS and 38,160 for
  re-operation.
• SCS was more dominant (more effective and less
  expensive) than re-operation in incremental
  cost-effectiveness and cost-utility ratios.

Intention-to-Treat Cost-effectiveness Plane
This ITT bootstrap simulation for incremental
costs and QALYs shows that 59 of results fall in
the lower right-hand plane. This finding
demonstrates that SCS is more effective and less
costly compared to re-operation. Further,
approximately 72 of results fall below the
cost-effectiveness threshold (40,000) routinely
used by US health policy makers.
9
Cost StudyTaylor RJ, et al. 200514

• Decision-analytic and Markov model to assess SCS
  for FBSS relative to conventional medical
  management (CMM).
• The 2-year base case cost for SCS was 16,250 vs.
  13,248 for CMM, giving an incremental cost of
  3,002 for SCS. Incremental utility for SCS was
  0.066 QALYs per patient.
• The lifetime base cost for an average patient was
  75,758 for SCS vs. 122,725 for CMM, giving an
  incremental cost of 46,967 for CMM. Incremental
  utility for SCS was 1.12 QALYs per patient.

Based on economic study of SCS for FBSS by
Kumar, et al. Health care costs were converted
from Canadian dollars at year 2000 prices to
Euros at Year 2003 prices, based on both
purchasing parity and health care cost inflation
in the European Union. Costs were discounted at
6.
10
Additional Cost StudiesKumar K, et al. 200615
and Kumar K, et al. 200216 and Bell GK., et al.
199717

• Calculated actual health care costs (2005
  Canadian) for SCS and its complications in 160
  consecutive patients. Mean cost of SCS implant
  was 23,205 with 3,609 in maintenance costs per
  year for an uncomplicated case.15
• Calculated actual 5-year health care costs (2000
  Canadian) for 60 FBSS patients with SCS matched
  to 44 with CMM. Mean 5-year cost for SCS was
  29,123 per patient vs. 38,029 per patient for
  CMM. SCS was cost-effective after 2.5 years.16
• 5-year health care cost model (1994 US) for two
  identical FBSS patients, one with SCS and one
  with back surgery. 5-year cost for SCS was
  80,000 on a charges basis vs. 82,630 for
  surgery. For the patient who passes the SCS
  trial and for whom SCS is effective, SCS pays for
  itself within 2.1 years.17

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Summary

• In all referenced clinical studies,1-3,5-12
  including two RCTs, SCS was effective in
  controlling the pain of FBSS long-term. SCS has
  been associated with substantial reduction in
  medication3,5,10,11 and significant increases in
  activities of daily living.1,7,11 Five studies
  found that SCS enabled return to work for an
  average of 27 of patients (range
  22-36).3,7,10-12
• The most frequent complication of SCS has been
  electrode migration (2-18).1,10-12 Electrode
  breakage from earlier studies9-12 did not occur
  in later studies.1,3,6,8 In five studies, 6-15
  of patients developed infection.6-7,10-12
  Various complications have also led to surgical
  revision of pulse generator, lead and/or system
  explantation.
• Cost studies showed that mean first-year cost
  becomes substantially less in the second year.

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Conclusions

• The long-term clinical studies that are
  summarized have shown that SCS is effective in
  controlling pain associated with FBSS, providing
  50 relief in 48-91 of the patients among
  these studies.
• Two economic studies indicated that as compared
  to CMM, SCS should become cost-effective after
  about 2 years.16,17

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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, Taylor R, Jacques L, et al. Spinal cord
  stimulation versus conventional medical
  management for neuropathic pain a multicentre
  randomized controlled trial in patients with
  failed back surgery syndrome. Pain.
  2007132(1-2)179-188.
• 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.
• Devulder J, De Laat M, Van Bastelaere M, Rolly G.
  Spinal cord stimulation a valuable treatment for
  chronic failed back surgery patients. J Pain
  Symptom Manage. 199713296-301.
• Heidecke V, Rainov NG, Burket W. Hardware
  failures in spinal cord stimulation for failed
  back surgery syndrome. Neuromodulation.
  2000327-30.
• North RB, Kidd DH, Farrokhi F, Piantadosi SA.
  Spinal cord stimulation versus repeated
  lumbosacral spine surgery for chronic pain a
  randomized, controlled trial. Neurosurgery.
  20055698-107.
• Leveque J-C, Villavicencio AT, Bulsara KR, et al.
  Spinal cord stimulation for failed lower back
  surgery syndrome. Neuromodulation. 200141-9.
• Dario A, Fortini G, Bertollo D, et al. Treatment
  of failed back surgery syndrome. Neuromodulation.
  20014105-110.
• Ohnmeiss DD, Rashbaum RF. Patient satisfaction
  with spinal cord stimulation for predominant
  complaints of chronic, intractable low back pain.
  Spine J. 20011358-363.
• Rainov NG, Heidecke V, Burkert W. Short
  test-period spinal cord stimulation for failed
  back surgery syndrome. Minim Invasive Neurosurg.
  19963941-44.
• Fiume D, Sherkat S, Callovini GM, et al.
  Treatment of failed back syndrome due to
  lumbo-sacral epidural fibrosis. Acta Neurochir.
  1995(Suppl)64116-118.
• De La Porte C,Van de Kelft E. Spinal cord
  stimulation in failed back surgery syndrome.
  Pain. 19935255-61.
• North RB, Ewend MG, Lawton MT, et al. Failed back
  surgery syndrome 5-year follow-up after spinal
  cord stimulator implantation. Neurosurgery.
  199128692-699.
• North RB, Kidd D, Shipley J, et al. Spinal cord
  stimulation versus reoperation for failed back
  surgery syndrome a cost-effectiveness and cost
  utility analysis based on a randomized,
  controlled trial. Neurosurgery. 200761361-369.
• 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.
• Kumar K, Wilson JR, Taylor RS, Gupta S.
  Complications of spinal cord stimulation,
  suggestions to improve outcome, and financial
  impact. J Neurosurg Spine. 2006519-203.
• 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.
• Bell GK, Kidd D, North RB. Cost-effective
  analysis of spinal cord stimulation in treatment
  of failed back surgery syndrome. J Pain Symptom
  Manage. 19971328-295.

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Thank you
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