American Society of Regional Anesthesia and Pain Medicine August 2016 - 19

Figure 1: The SENZA High Frequency Platform (SENZA, HF10, Nevro,
and the Nevro logo are trademarks of Nevro Corp).

At 24 months, the HF10 therapy responder rate remained higher
(79% for back pain and 75% for leg pain) compared with traditional
SCS (49% for back pain and 51% for leg pain). A higher proportion
of subjects reported minimal or moderate disability with HF10
therapy compared with traditional SCS (65% vs 49%). As with
the 12-month results, nearly two-thirds of the subjects reported
profound pain relief.
DORSAL ROOT GANGLION STIMULATION
In recent animal models, it was shown that several
pathophysiologic changes occur in the DRG in response to pain,
including altered electrophysiological membrane properties,
changes in the expression of integral membrane proteins, and
altered gene expression. These changes may explain how the DRG
plays a major role in the development and maintenance of chronic
pain.
Stimulation of the DRG can result in subdermatomal patterns of
paresthesia coverage, recruiting more specific sensory neuron
somas, which may allow more precise paresthesia coverage in
the body relative to traditional SCS. This precision would be very
beneficial in cases of pain distributions in regions that are typically
difficult to cover or treat with traditional SCS. Other advantages
for DRGS are its predictable location within the epidural space and
lack of cerebrospinal fluid around it, which allows for increased
energy efficiency and lower energy consumption than conventional
SCS5.
Recently, the Food and Drug Administration (FDA) approved DRGS
based in part on the results of the ACCURATE IDE study (Figure
2). The study evaluated patients suffering from neuropathic,
chronic, intractable pain associated with CRPS (types I and II)
or peripheral causalgia. In the study, patients were randomized
between using the DRGS compared with traditional SCS.
After 12 months, the ACCURATE study demonstrated that a

Figure 2: Axium dorsal root ganglion stimulation system. Courtesy of St.
Jude Medical.

statistically significantly number of patients receiving DRGS
achieved meaningful pain relief and greater treatment success
when compared with patients receiving traditional SCS (74.2%
vs 53%). Interestingly, more than a third of patients who
received DRGS experienced greater than 80% pain relief with
no paresthesia. Nearly all patients receiving DRGS reported
better stimulation targeting their area of pain without extraneous
paresthesia than the control group with traditional SCS (94.5% vs
61.2%).
Multiple studies done by our colleagues in Europe and Australia
have shown DRGS to have promising results in the management
of chronic neuropathic, groin, postthoractomy, and phantom limb
pain.6
OTHER INNOVATIONS COMING SOON
Burst Technology. Awaiting FDA approval, the new burst
technology is a form of stimulation in which quanta of highfrequency impulses are delivered periodically (five pulses at 500
Hz, delivered 40 times per second). Multiple trials have shown not
only that burst stimulation suppresses pain at least as well as-
and possibly better than-tonic stimulation but also that pain relief
is provided with significant reduction in paresthesia or most of the
times paresthesia free.7,8
Wireless SCS Therapy. A unique injectable wirelessly powered
SCS technology was recently approved by the FDA. This might
decrease some procedural problems by eliminating the need for
an implantable pulse generator (IPG) by relocating the functionality
outside of the body. This innovation may drastically reduce
procedure time as there is no need for a second incision and
pocketing of the IPG, allowing for a longer trial period and making
revision or replacement surgeries a nonissue.9

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2016

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Table of Contents for the Digital Edition of American Society of Regional Anesthesia and Pain Medicine August 2016