Canadian RMT Spring 2018 Canadian RMT Spring 2018 | Page 14

Assessing Neurogenic
Thoracic Outlet
Syndrome
Double Crushed Nerve Damage
By Erik Dalton, Ph.D.
T
he term double crush syndrome (DCS) was coined by
Harvard University plastic surgeons Albert Upton and
Alan McComas, who wrote, “Neural function is impaired
when compressed axons at one site cause the nerve to become
especially susceptible to damage at another site” (Image 1).
Their double crush research began after observing that many
carpal, cubital, and radial tunnel patients also complained of
1
unilateral shoulder, chest, and upper back pain. While the DCS
mechanism is not completely understood, it likely involves
nerve sensitization and neuroplastic changes in the pain-modu-
lating systems of the brain and spinal cord.
Neural compression of the brachial plexus is suitably called
neurogenic thoracic outlet syndrome (NTOS). These clients
present with a variety of symptoms, including painless atrophy
of intrinsic hand muscles and nighttime paresthesia. Athletes
may have difficulty grasping a racquet or ball, and some report
pain. However, I’ve found that rather than being a main pain
event, NTOS is more of an enhancer of symptoms at a distal site,
such as the carpal tunnel. Put simply, the brain pays more atten-
tion to double crush nerve insults and is more likely to respond
with pain or spasm.
Although most clinicians feel that NTOS is an underestimated
cause of DCS, assessment is often difficult due to vague, fluctuat-
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Canadian rmt
ing symptoms. Instead of chasing the pain, I’ve achieved supe-
rior outcomes by palpating and releasing all fibrous connective
tissue sites that may be kinking, stretching, or inflaming the
brachial plexus. In the January/February 2016 (“An Alternat