Page 36 - IDF Journal 2023

IDF – Study Weekend IDF News – Spring 2023
Soft Tissue Thoracic Outlet Syndrome
The Most Missed Diagnosis?
Mr Richard Scott-Watson
We are all familiar (or were once!) with the anatomy of the thoracic outlet.
The area of concern is that part of the brachial plexus that goes from the scalene muscles to the axilla.
Pressure on nerves proximal to the scalene muscles will usually be a disc lesion
and will have the familiar dermatomal pattern of symptoms. The symptoms will usually be pretty constant and although they may vary in intensity, they normally will not resolve. The patient can usually identify what part of the arm is affected.
Pressure on nerves distal to the axilla will commonly be carpal tunnel syndrome or cubital tunnel syndrome. These will be more variable than disc lesions but again can be readily identified by most patients as to which area is affected.
Then comes the patient who has variable symptoms that fit neither pattern and come and go depending on activity. These are commonly associated with whiplash mechanism injuries but can also occur with many upper limb disorders.
The biggest problem with these patients is that many will not volunteer symptoms – after all they thought they had a neck problem and do not associate that with a hand problem. This means that patients have to be asked about the symptoms. The sort of activities that worsen are holding a phone, driving, and carrying something in the affected arm. Additional symptoms in women are that clothing straps fall off the affected side. Strangely, many notice this but do not notice that the unaffected side remains normal.
So, this is a condition that has to be looked for as it will usually not be volunteered. Having said that, I do occasionally diagnose it as the patient comes through the door, because they are so lopsided.
There are two common tests for the condition – Roos test which can only
be performed with good shoulder movement, or Adson’s test which relies less on shoulder movement. Personally, I find Roos test the best where possible.
Diagnostic tests such as nerve conduction studies and MRI are usually normal, but are worth doing as occasionally a more severe form may
REFERENCE
1. https://www.mayoclinic.org/diseases- conditions/thoracic-outlet-syndrome/ symptoms-causes/syc-20353988
The sort of activities
that worsen are holding a phone, driving, and carrying something in the affected arm.
be found. I have seen one associated with very tight scalene muscles and one with a cervical rib. The important thing about these tests is that they only show nerve conduction that has been affected sufficiently to alter the test result, or in the case of the MRI, the anatomy. Neither can be used to exclude the condition, and it should always be noted that the MRI does not inform about function, only structure.
Treatment is simple as it involved shoulder shrugs done half a dozen times per hour for every waking hour. If this does not cause irritation, then light weights can
be added. It can take several months to resolve symptoms because it is a muscle imbalance problem.
I give patients a pre-printed card reminding them of what to do. It also references the Mayo Clinic website which helpfully has ‘car accident’ as first on the list for causes of this condition1. The Mayo Clinic website is helpful corroboration for the patients
I see. I often show them the anatomy pictures if I think it will help. Some get it easily, others less so.
Mr Richard Scott-Watson BSc(Hons) MB BS LLB (Hons) (Open) CUEW DDAM FRCS(Ed)
E: rswandls@doctors.org.uk
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