New Orthopedic Test: Neurogenic Thoracic Outlet Syndrome
by Dr. William J. Owens, D.C., D.A.A.M.L.P.
The Journal of Vascular Surgery provides vascular, cardiothoracic, and general surgeons with the most recent information in vascular surgery. The Society for Vascular Surgery Journal of Vascular Surgery ranks in the top 5 percent of the 5,684 scientific journals most frequently cited. (2000 Science Citation Index)
When a patient presents for evaluation after a traumatic injury, extremity symptoms often accompany other subjective complaints. There are two main categories for these complaints: compressive injury and non-compressive injuries. The compressive injuries would include diagnosis of cervical intervertebral disc herniation causing nerve root impingement, symptomatic cervical ribs, Pectoralis Minor Syndrome, Scalenus Anticus Syndrome and fracture/dislocation. The non-compressive injuries include brachial plexus traction injuries and cervical radiculitis, both of which can be equivalent or worse than the more commonly diagnosed compression syndromes.
When moving away from the cervical spine, the path of neural and vascular elements from the neck into the upper extremity does leave these structures susceptible to impingement or traction injuries. These types of injuries fall under the Thoracic Outlet Syndrome (TOS). TOS has three main categories based on what types of structures are being compressed: Arterial TOS, Neurogenic TOS and Venous TOS.
Arterial TOS (ATOS) is the least common form and results in upper extremity symptoms due to loss of blood circulation. Color changes are noted in the fingers and particularly the nail beds. This is most commonly caused by embolus formation and subsequent blockage of the blood vessel. This accounts for less than 1 percent of all TOS. (Sander, et al., 2007, p601) This condition is almost always associated with a cervical rib or an anomalous first rib.
Venous TOS (VTOS) has an incidence of approximately 3 percent. (Sander, et al., 2007, p601) "VTOS, sometimes called effort thrombosis or Paget-Schrotter disease, may be preceded by excessive activity with the arms." (Sander et al 2007, p601) This is different than ATOS, as ATOS is caused rather spontaneously unrelated to work or trauma, while VTOS tends to be more repetitive in nature. It is characterized by swelling of the extremity causing secondary paresthesia.
Neurogenic TOS (NTOS) is, by far, the most common form of TOS. This type of TOS includes neck pain and occipital headaches along with upper extremity symptoms. Raynaud’s phenomenon is also frequently seen in NTOS, which can lead to an inaccurate diagnosis of ATOS. "These color and temperature changes are often a result of an overactive sympathetic nervous system which follows nerve roots C8, T1 and the lower trunk of the brachial plexus, (Sander, et al., 2007, p602) and not an embolism".
NTOS is certainly an under-diagnosed condition. Many of the historical tests challenge the vascular portion of the disorder by stressing the neurovascular bundle, then testing for pulse strength distal to the point of compression. With the actual incidence of ATOS being less than 1 percent, these types of tests are often negative, steering the clinician away from a qualified and accurate TOS diagnosis.
When looking for a way to rule out these conditions and to sort through your differential diagnosis for the upper extremity symptoms, MRI and EMG/NCV are the most common tools to utilize to secure an accurate diagnosis. In situations where there is a direct compressive injury, EMG/NCV are the studies of choice and are very effective at demonstrating loss of nerve function and nerve signal velocity. MRI is also quite good at showing herniation of the intervertebral disc and compression of the exiting nerve root. The best cases are the ones where everything lines up in textbook format and we get a clear picture of the patient’s injury, diagnose them properly, determine causality and offer a realistic prognosis based on the findings. What if they do not line up so well? Do you continue as a clinical detective and search for less common methods or do you simply give up on the patient?
The cases that do not line up so easily have to do with injuries resulting in the second category or non-compressive injuries (NCI). NCI are far more common than many clinicians realize and can certainly cause as much pain and functional loss as their compressive counterparts. The NCI are most commonly caused by traction, stretching or shearing type forces. This is often seen in whiplash patients as the head and neck is separated from the brachial region, especially in lateral side impact situations. The "T-Bone" impact is a classic example of a lateral whiplash mechanism. Many lateral whiplash patients present with upper extremity symptoms in the absence of herniation of the intervertebral disc.
The most current orthopedic test for the diagnosis of NTOS is called the Upper Limb Test of Elvey (ULLT) and is a modified version of the original test of Elvey. It was published for the first time in this article being reviewed. The important aspect of this test is that the asymptomatic side serves as a control for the symptomatic side being tested. The test is outlined on page 603 including great pictures. The test is performed as follows:
1. Abduct both arms to 90° with the elbows straight;
2. Dorsiflex both wrists;
3. Tilt the head to one side, ear to shoulder. The head is then tiled to the other side. While position 1 and 2 elicit symptoms on the ipsilateral side, position 3 elicits symptoms on the contralateral side.
In conclusion, the authors remind the reader that TOS is NOT a specific diagnosis and should be qualified with the appropriate type of TOS. The ULTT is comparable to the Straight Leg Raise in the lower extremity and is very useful in the diagnosis of NTOS. This is one of the many tools available to the medical legal professional to produce an accurate and defensible diagnosis.
In each issue, a clinical topic is covered by William J. Owens of the American Academy of Medical Legal Professionals (AAMLP), which is a national, non-profit organization, comprised of doctors and lawyers. The purpose of the organization is to provide its members with current research in trauma and spinal related topics, to keep the profession on the cutting edge of healthcare. Members may also sit for a Diplomate examination and be conferred a DAAMLP. The organization also offers support to the individual member’s practice.
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