GB> >My rheumatologist and my hand surgeon both call it Thoracic-outlet-syndrome
GB> >Poor posture over time that pinches and irritates nerves (amoung other thin
GB> Different syndrome than ulnar palsy. You should have said so in
GB> the first place. Thoracic outlet is a bit more problematical
GB> to treat. Sometimes a cervical rib can cause it. If so, the
GB> rib may have to be removed. Sometimes one of the scalenus muscles
GB> can cause the problem and can be severed to relieve the compression.
GB> You need a real good electrodiagnostic study if you haven't had it.
Amen. NTOS (neurogenic thoracic outlet syndrome) was well reviewed
by Wilbourn and Aminoff about 3 years ago in Muscle & Nerve. (The
authors also detailed severe reflex sympathetic dystrophy caused by
misguided surgical attempts to treat it.) In the authors' opinions,
NTOS is a genuine entity; each author had seen several cases. It
is, however, an extremely rare condition. It is overdiagnosed in
patients with nonspecific symptoms and without objective neurologic
or EMG findings. Wilbourn and Aminoff would call the latter
condition "disputed" NTOS, as opposed to the "true" NTOS that they
were writing about.
True NTOS is a chronic entrapment syndrome of the brachial plexus
involving the lower trunk (i.e., C8-T1) or medial cord (i.e., ulnar
nerve and medial head of the median nerve). There are paresthesias
of the ulnar border of the forearm and hand, similar to a C8
radiculopathy. Most importantly, there is atrophy of the thenar and
hypothenar eminence, with weakness of median-innervated hand muscles
as well as all ulnar innervated muscles. There may also be weakness
of the long finger flexors (flexor pollicis longus and flexor
digitorum profundus). Obviously, the condition is confirmed by EMG.
Radiologic studies show the cervical rib or elongated transverse
process of C7 that is impinging on the lower brachial plexus. Other
conditions causing lower trunk/medial cord neuropathy (e.g., superior
sulcus tumor, invasive {*filter*} cancer, Parsonage-Turner brachial
plexus neuropathy) must be excluded.
NTOS would be a rare medical curiosity except for the actions of
surgeons who make the diagnosis based on examination of the
patient's health insurance rather than examination of nerves and
muscles. This isn't just my opinion - a recent audit in Colorado
showed the diagnosis made a hundredfold more often in patients with
private insurance than in Medicaid patients. My advice to anyone
who has been given the diagnosis of NTOS is to get another one -
from an independent neurologist and EMGer.
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. SLMR 2.1 .
Thoracic Outlet Syndrome