Neurogenic Thoracic Outlet Syndrome
The thoracic outlet is the general space between your collar bone and your armpit, that passes between the underneath surface of your collar bone and the the upper surface of the first rib. Theoretically, the blood vessels or nerves going through this “outlet” can become compressed. When the nerves are compressed, it is referred to as Neurogenic Thoracic Outlet Syndrome (NTOS) and when the blood vessels are compressed it is referred to as Vascular Thoracic Outlet Syndrome (VTOS). The compression can occur at multiple points with the most common being between the scalene muscles that attach to the first rib or between the actual bone boundaries of the outlet in the first rib and clavicle (collar bone). It is believed to occur due to abnormal anatomy in this area or can be a result of trauma that can present in a delayed fashion.
Athletes can can be young and otherwise healthy and present with a highly variable set of symptoms. It is believed that the majority of the cases of Thoracic Outlet Syndrome are neurogenic in nature. The syndrome consists of multiple symptoms including extremity weakness, numbness and pain that can present with activity, rest or even sleep. Athletes with overhead activities may present with upper arm heaviness as well.
Making the Diagnosis?
I won’t get bogged down in to the details, but there are several test that can be done looking for this diagnosis. The overall gist is to put the arm and neck in a position that can cause compression of the the thoracic outlet, which in turn will replicate the symptoms. An x-ray is usually preformed to see if there is a bony abnormality such as an extra cervical rib or old rib fracture that is causing the symptoms. An MRI with dye injected into the blood stream can also be performed to look at the soft tissue anatomy as well track compression of the nerve and blood vessels in the thoracic outlet. Lastly, ultrasound can be used to look at the flow through the blood vessels as well as possible nerve injury.
Non-surgical treatment includes physical therapy, stretches, range of motion and nerve mobilization techniques. If the compression is due to muscular compression, Bo-Tox injections can be used to relax the muscle and potentially reduce the compression. Surgical treatment includes decompression of the area, which may include resection of the rib, portions of muscle or scar tissue.
What Else to Consider?
It is not entirely clear how they arrived at NTOS after year but other diagnosis should be considered. Parsonage-Turner Syndrome and Complex Regional Pain Syndrome are definitely diagnosis I would pursue. Good news is the therapy for NTOS should be pretty similar to these other diagnosis so we will have to wait and see.
Reference: Kuhn JE, Lebus V GF, Bible JE. Thoracic outlet syndrome. J Am Acad Orthop Surg. 2015 Apr;23(4):222-32. doi: 10.5435/JAAOS-D-13-00215. Review. PubMed PMID: 25808686