Neuromodulaton Clinical Trial
Official title:
Short and Long Term Exposure to Unique, Time-Varying Pulsed Electro-Magnetic Fields in Refractory Carpal Tunnel Syndrome (Cts): A Randomized, Placebo-Controlled Trial With Secondary Bayesian Modification
Pulsed electromagnetic fields (PEMF) have been approved by FDA and are utilized currently in treating non-union fractures, neurogenic bladder and musculoskeletal pains. Based on 2 prior pilot studies (open label) demonstrating reduction in neuropathic pain from carpal tunnel syndrome we decided to perform a placebo-controlled trial, randomized for 2 months utilizing a wrist PEMF device attached by Velcro for 4 hours/day.
INTRODUCTION:
Entrapment of the median nerve at the wrist is the most common cause of sensory and motor
disturbance in the hands and can be progressively disabling.1,2 Complex mechanisms of
compression and ischemia exist that adversely influence the large A myelinated fibers and
small unmyelinated nociceptive C fibers. From a pathophysiological standpoint, neuropathic
pain (numbness, tingling and burning, NP) is believed secondary to ectopic firing of
nociceptive afferent unmyelinated C-fiber axons that are undergoing degeneration.3
Microneurography has confirmed that dysregulated expression of sodium and calcium channels,
which accumulate at site of injury, are responsible for ectopic depolarization.3,4,53,54
When conventional therapy of splinting and pharmacotherapy fail, surgical decompression has
been offered for moderate-severe cases. While usually successful, it is associated with
significant complications, limitations and costs.5,6,7 Thus, the search for reliable and new
therapeutic strategies is appealing.
Substantial evidence exists that time-varying magnetic fields produce biological effects by
safely inducing extremely low-frequency (ELF) small electrical eddy currents within the
tissues that can depolarize, repolarize and hyperpolarize neurons.8,9,10,11,12
Prior pilot data using static13 and pulsed magnetic fields (PEMF)14,15 directed to the
carpal tunnel region significantly reduced NP. Since a new, novel device became commercially
available that produced a combination of static and time-varying magnetic fields
simultaneously, it was hypothesized that this energy could be directed into the wrists and
potentially influence not only NP scores, but also modulate neuronal distal latencies
(neurotransmission).
DEVICE:
DESCRIPTION: (FIGURE 1) This patented device (Biaxial Super Mini [Mx2R] by Nikken, Inc.)
measures 2" in diameter and 1" in height and is worn with a Velcro strap similar to a
wristwatch. It is noiseless and nonthermal. Its main component is a spherical permanent
magnet, 1150G, 3/8" in diameter that rotates in two perpendicular directions simultaneously
producing biaxial magnetic rotation (MX2R) and oscillating polarities up to 1,200 rpm-20
times per second. It is driven by a 2 V DC micro-motor which is shielded one inch away and
produces a negligible back EMF. The device is powered by three ¼ AAA rechargeable NiMH
(Nickel Metal Hydride) batteries
Randomized double blind placebo-controlled device with primary parameters of pain and sleep
interupption scores, NPS scale and secondary parameters of neurological exam changes, nerve
conduction latencies of median nerve, dynamometry, finger gauge pressures, CPT and PGIC were
compared at baseline and end of two months. Patients were given a free "active" device
gratis at end of study.
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Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double-Blind, Primary Purpose: Treatment