TOS Protocol

[Linh]

Hi Steve,

How are you? I hope you are doing well.

I was wondering if you have a protocol for Thoracic outlet syndrome. I know assessing the nerve is underwhelming but for arterial and venous TOS, US definitely has a role. I would typically get a Pulsed trace at rest of the subclavian artery immediately just infraclavicular, then at 90 degrees abduction and then 180 degrees abduction with sustained arm abduction for awhile until the symptoms comes on. I will upload what I did today tomorrow as I just diagnosed a mixed TOS with both Arterial and venous compression with reproduction of the patient’s sharp nerve pain at radial 3 fingers bilaterally (MR angiogram also confirmed). Also, what is the Adson’s test and does this have a role in TOS imaging?

In the meantime, I am curious as to how you logically tackle this.

Best regards,
Linh

[Stephen Bird]

Hi Linh,

Your technique is the same as mine,

I like the way you have conducted the examination.

The Adson’s test is a provocative manoeuvre.

With the patient sitting on a chair or the bed place the ipsilateral arm into 30 degrees of shoulder abduction with elbow extension.
Then externally rotate the shoulder slightly (pull their arm back a little).
Then ask the patient to turn their head and look towards the side being examined.
Then ask them to take a breath in and hold it.

When you scan the subclavian artery in the location you have described you will see a high grade stenosis or occlusion if it is positive.

The only think that worries me a little is that if you pull the arm back too far it can be positive in normal volunteers. So I stick to a more natural physiological range of movement that the patient would do in everyday life.

In my experience, when they are positive and symptomatic, the simple act of placing the shoulder into 90 degrees of abduction and making a stop sign posture will create a high grade stenosis or occlusion of the subclavian artery. So whenever they do anything above their head they are occluding. Not much fun if you are hanging out washing, painting a ceiling, stacking high shelves, or working under a car on a hoist as a mechanic!

Great work Linh,

Steve

[Linh]

Thanks for getting back to me so promptly Steve!

Do you also take traces of the subclavian vein? I only assess it in B mode as the patient abducts their arm and also to be sure theres no DVT. On a normal volunteer, do you see it get compressed with arm abduction also?

Here are the pics:

Attachments:

You must be logged in to view attached files.

[Linh]

Here are the RT side pics:

Please critique freely as I don’t do this everyday and want to get better 🙂

The velocity trippled from 100s to 300s and at times I can see turbulence on the LT side (which is more symptomatic with numbness and tingling at 180 degrees) but not on the RT side (feeling stiff but not too much pain).

Attachments:

You must be logged in to view attached files.

[Author]

Posts