Thoracic Outlet Syndrome

WHAT IS THORACIC OUTLET SYNDROME (TOS)?

The thoracic outlet is part of the shoulder and upper extremity that consists of three spaces between the clavicle and first rib which houses several neurovascular structures including the brachial plexus, subclavian artery and subclavian vein. Thoracic outlet syndrome occurs when one of these structures is compressed which can elicit a multitude of symptoms in the upper extremity (Jones et al, 2019).
There are three different classifications of TOS–neurogenic, venous and arterial–with neurogenic representing over 90% of all cases. Each of these three subgroups may have congenital, traumatic or functionally acquired causes. Congenital issues arise from the presence of a cervical rib or anomalous rib. Traumatic causes include whiplash injuries and falls and functionally acquired causes typical result from strenuous, repetitive activity as seen in sports and work (Jones et al, 2019).

SYMPTOMS

The location and classification of pain is the largest determinant of what type of TOS a patient has. Neurogenic thoracic outlet syndrome (NTOS) may result in pain, tingling and weakness of the upper extremity into the neck, as well as occipital headaches. Venous thoracic outlet syndrome (VTOS) can cause swelling of the arm, bluish discoloration of the skin, pain or aching. Arterial thoracic outlet syndrome (ATOS), the least common type, may cause finger discoloration, pallor, coldness, tingling and pain in the hand. This pain rarely extends into the shoulder or neck (Sanders et al, 2007).

HOW IS TOS DIAGNOSED?

TOS diagnosis relies on a combination of clinical maneuvers that stress the affected structures while looking for symptom exacerbation, patient history, and physical presentation on exam. The exam will include the upper extremity, shoulder and neck region as well as posture. When TOS is suspected, imaging studies (EMG, MRI, X-Ray, etc) may be utilized for further diagnosis (Jones et al, 2019).

TREATMENT

Conservative Treatment

Typical treatments include pharmaceuticals, physical therapy and activity modification. Physical therapy can address active stretching and strengthening of the involved area as well as improve postural mechanics. Activity modification includes weight control and relaxation techniques. Anti-inflammatory drugs (NSAIDs) and muscle relaxers may be used for pain relief. Many patients experience symptom relief without need for further intervention.
Osteopathic Manipulative Medicine (OMM)
- OMM is a treatment approach that consists of a variety of hands-on techniques used in conjunction with other standard of care modalities to improve overall function. OMM aims to alleviate dysfunction and restriction of the musculature surrounding the shoulder and neck, which results in a decompression of the brachial plexus and a relief of symptoms. Manipulation of the first rib through various OMM techniques can have an immediate effect on TOS symptomatology.
Nerve Hydrodissection
- Using ultrasound guidance, the physician identifies the nerves and guides the needle next to the nerve. Fluid (typically saline/lidocaine) is injected around the nerve to free the nerve from surrounding tissues. This can have the same effect as a surgical release, with resolution of the numbness, tingling and pain.

Surgical Intervention

The most common surgical intervention for TOS is removal of the first rib in order to decompress the brachial plexus. Depending which structures are involved, there are different approaches, all of which have shown good outcomes. The first rib can be accessed through the scalene muscle, or between the pectoralis major and latissimus dorsi in the armpit. In rare instances, direct access to the subclavian vein is needed in order to provide a vascular reconstruction (Jone et al, 2019).
Technique is often chosen based on the individual patient and unique anatomical considerations.

REFERENCES

Jones MR, Prabhakar A, Viswanath O, Urits I, Green JB, Kendrick JB, Brunk AJ, Eng MR, Orhurhu V, Cornett EM, Kaye AD. Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. Pain Ther. 2019 Jun;8(1):5-18. doi: 10.1007/s40122-019-0124-2. Epub 2019 Apr 29. PMID: 31037504; PMCID: PMC6514035

Sanders, R. J., Hammond, S. L., & Rao, N. M. (2007). Diagnosis of thoracic outlet syndrome. Journal of Vascular Surgery, 46(3), 601–604. https://doi.org/10.1016/j.jvs....