New Rechargeable Spinal Cord Stimulator Systems Offer
Advantages in CRPS Treatment
By Joshua P. Prager, MD, MS
Director, Center for the Rehabilitation of Pain Syndromes
Departments of Internal Medicine and Anesthesiology
David Geffen School of Medicine at UCLA
In April, 2004, the Food and Drug Administration (FDA) approved
the first rechargeable spinal cord stimulator (SCS) system.
This system, called Precision, produced by Advanced
Bionics, is the first in a new generation of SCS systems that
offers a significant improvement in stimulation to people
with CRPS. In early 2005, Advanced Neuromodulation Systems
rechargeable system, the Eon, was approved and shortly
thereafter Medtronic, the largest producer of neurostimulator
systems, received FDA approval for its Restore System.
This article will briefly review the use of SCS for treatment
of CRPS and then describe the potential of the new systems
in improving care and outcomes.
SCS as Part of the CRPS Treatment Algorithm
In 1995, the International Association for the Study of
Pain (IASP) brought together a group of international experts
to address treatment of CRPS. This was one of four meetings
the IASP has held in the last two decades regarding various
aspects of CRPS. Stanton-Hicks published results of the 1995
meeting as a treatment algorithm, which indicates that the
mainstay of CRPS/RSD treatment is physical therapy, and that
nerve blocks or SCS as adjuvant treatment are important for
patients who are not adequately progressing with physical
therapy alone. The important point of this article is that
SCS can significantly enhance CRPS treatment by facilitating
physical therapy as part of the entire rehabilitation process.
Stanton-Hicks suggested that the beneficial effect of SCS
relates not only to pain relief, but it also to inhibits or
modulates the sympathetic outflow to the region where the
tingling produced by the stimulation is experienced.
SCS and CRPS
There have been numerous studies of SCS for the treatment
of CRPS. These studies have been both retrospective and prospective
randomized. In 1982, Broseta reported the use of SCS for CRPS-2
patients with 72 percent having experienced excellent results.
Barolat reported a 73 percent success rate of pain in 18 patients
with CRPS-1. Kumar discussed 12 patients treated with SCS
for CRPS. Robaina compared SCS with TENS in 35 patients with
late-stage CRPS-1; 66 percent of patients reported good results
with SCS, experiencing rapid relief of pain and reduction
in swelling. Bennett examined not only the effect of SCS on
CRPS, but also looked at the effect of different lead arrays.
He found that patient satisfaction was markedly improved with
dual octapolar leads as opposed to traditional quadripolar
There have been four prospective studies published of spinal
cord stimulation in CRPS. The first, Calvillo in 1998, examined
31 patients with CRPS affecting the upper extremity with a
significant reduction in pain scores compared to baseline.
Oakley and Weiner observed statistically significant reduction
in pain and an 80 percent success rate with SCS for CRPS.
The largest prospective study in CRPS was that of Kemler ,
in the New England Journal of Medicine in 2000; 54 patients
with CRPS-1 of one extremity were randomized to SCS plus physical
therapy or physical therapy alone. A significantly greater
number of patients with SCS plus physical therapy had a much
improved global perceived effect than the physical therapy
group alone. Most recently, Kemler published a two-year followup
of the randomized trial. The mean pain score in the 24 implanted
SCS patients was significantly reduced compared to those receiving
physical therapy alone; 63 of the SCS patients reported improvement
in their global perceived effect.
Thus, there is significant literature demonstrating the success
with SCS in treating CRPS. This brief discussion above was
not meant to thoroughly review or evaluate this literature,
but merely to call attention to its presence and provide a
reference list where one can review this information in greater
Rechargeability and its Implication toward the Treatment
of CRPS with SCS
The advent of rechargeability, being able to recharge the
SCS battery, creates new opportunities. Previously, when a
battery failed, the entire pulse generator needed to be replaced,
which required expensive surgery and was uncomfortable for
the patient. Rechargeability may significantly reduce the
need to replace internal pulse generators.
Many CRPS patients with SCS systems have needed to use a
lot of power to achieve the pain relief necessary to function.
In order to reduce the need to replace the internal pulse
generator, patients have often rationed the amount of stimulation
by either reducing the power or turning the unit off some
of the time. Thus, both patient and physician have attempted
to manage the battery while compromising treatment. Rechargeability
offers the opportunity to manage the patient instead of managing
Bennett notes that large arrays produce greater satisfaction
than traditional quadripolar leads. Rechargeability offers
the opportunity to use many contacts simultaneously, which
uses a significantly greater amount of energy. Previously,
this increased power consumption would have been prohibitive
in some patients. Rechargeability allows the use of a greater
number of electrodes at a given time to provide better coverage
There are some reports that increased frequency improves
stimulation in patients with CRPS. Although this not been
well documented, it is important to note that higher frequency
produces higher energy consumption. Higher frequency potentially
compromises battery life. Thus, rechargeability provides an
opportunity to fully utilize the potential of any system without
needing to worry about battery failure.
Conventional SCS four-and eight-contact leads were placed
relatively far apart. Oakley and Prager in their discussion
of SCS, indicate that when SCS leads are placed closer together
the result is deeper penetration of the spinal cord, which
provides a stronger effect. New lead configurations have been
and will be designed specifically for rechargeable systems
because the more-effective configurations will use more energy.
Thus, once again, rechargeability provides a platform to allow
for a more effective form of stimulation that conventional
primary cell internal pulse generator source would not support.
Cost-Effectiveness of SCS
Taylor et.al recently reviewed the cost effectiveness
of SCS for treating chronic pain. They conclude that in the
medium to long term, SCS is economically favorable compared
to other therapies for people with CRPS. Taylor indicates
that pay back ranged from 15 months to five years after the
SCS was implanted. The pay back period was sensitive to the
efficiency level of the battery/electrode life and the amount
of patient usage. However, this review was performed before
rechargeable batteries. Considering the advantages of rechargeability,
it is possible that pay back will be shortened and that the
costs of SCS plus physical therapy will be lower than the
cost of physical therapy alone. SCS initial costs are offset
by a reduction in healthcare expenditures after the implant.
The Future with Rechargeability
The release of rechargeable systems has prompted the development
of many new lead configurations that will enhance the effectiveness
of SCS for the CRPS patient. New leads and extensions are
currently in development. In particular, one product that
will be available in the near future will allow four limbs
to be treated simultaneously from a single-pulse generator.
For patients with advanced four-limb CRPS, this eliminates
the need for multiple systems; four limbs can be treated with
a rechargeable single-pulse generator that, despite high energy
consumption, will not require frequent replacement.
Spinal cord stimulation has a demonstrated efficacy in
treating patients with CRPS when it is used in conjunction
with a comprehensive rehabilitation program. Rechargeability
enhances the ability to perform stimulation without requiring
as frequent internal pulse generator battery replacements.
SCS is cost effective in CRPS and future developments will
enhance its effectiveness.
1. Stanton Hicks, M. et.al. An updated interdisciplinary clinical
pathway for CRPS: Report of an expert panel. Pain Practice
2. Stanton-Hicks M., Spinal cord stimulation for the management
of complex regional pain syndromes. Neuromodulation 1999;
3. Broseta J, et.al. Chronic epidural dorsal column stimulation
in the treatment of causalgia pain. Appl Neurophys 1982;45:
4. Barolat G. Schwartzman R., et.al., Epidural spinal cord
stimulation management of reflex sympathetic dystrophy. Stereotact
Funct Neurosurg 1999; 53:29-39.
5. Kumar K., et.al., Spinal cord stimulation is effective
in the management of reflex sympathetic dystrophy. Neurosurgery
6. Robaina F. J., et.al., Transcutaneous electrical nerve
stimulation and spinal cord stimulation for pain relief in
reflex sympathetic dystrophy. Stereotact Funct Neurosurg 1989;
7. Bennett D. S., et.al., Spinal cord stimulation for complex
regional pain syndrome (RSD): A retrospective multicenter
experience from 1995-1998 of 100 patients. Neuromodulation
8. Calvillo O, et.al., Neuroaugmentation in treatment of complex
regional pain syndrome of the upper extremity. Acta Orthop
Belg 1998; 64: 57-62.
9. Oakley, J. and Weiner, R. L., Spinal cord stimulation for
complex regional pain syndrome: A prospective study of 19
patients at two centers. Neuromodulation 1999; 2:47-50.
10. Kemler, M.A., et.al., Spinal cord stimulation in patients
with chronic reflex dystrophy. N Engl J Med 2000; 43:618-24.
11. Kemler, M.A., The effect of spinal cord stimulation in
patients with chronic reflex sympathetic dystrophy: Two years
followup of the randomized control trial. Ann Neurol 2004;
12. Bennett, D.S., ibid.
13. Oakley, J., Prager, J., Mechanism of spinal cord stimulation.
Spine. 27 (22):2574-2583.
14. Taylor, R. S., The cost effectiveness of spinal cord stimulation:
A systematic review of the literature. J Pain Symptom Manage
2004; 27 (4): 370-8.
Updated February 27, 2006