Among the most common types of nerve entrapment is Thoracic Outlet Syndrome (TOS) causing pain and weakness in the neck, shoulder, arm and hand.

Although all physicians understand the role of the spine problems in causing shoulder and arm pain, there is a great deal of controversy and confusion regarding the diagnosis of thoracic outlet syndrome. Nerve entrapment of the median nerve in the wrist at the carpal tunnel can affect the thumb and next two fingers - carpal tunnel syndrome. Entrapment of the ulnar nerve at the elbow is cubital tunnel syndrome. However between the spine and the elbow there are many nerves, crossing a long course when these nerves become entrapped or injured, the diagnosis may be TOS.

Thoracic outlet syndrome can affect the blood vessels, or the nerves or both. In the past, it has been easy to diagnose TOS affecting thed blood vessels - causing loss of blood flow when the arms are raised. However, diagnostic proof of TOS affecting the nerves has been considered unsatisfactory or very difficult to achieve. Now, the advent of MR Neurography and Open MR guided injections has revolutionized diagnosis and treatment in this field. With these techniques, Dr. Filler at the Institute for Nerve Medicine has shown that TOS can be divided into as many as six different types of nerve entrapment. Each of these can be reliably and confidently identified and new, minimally invasive treatments are now avaiable for each of these.

In the past, the only surgery widely offered for the treatment of TOS was resection of the first rib. This is a very invasive and difficult operation with an extended recovery period and a very significant risk of major injury to blood vessels, nerves or lung during the operation. Dr. Filler has shown that if the inidividual type of TOS affecting a patient is known in advance, then it is usually possible to plan a small, safe minimally invasive surgery to correct the problem - usually on an outpatient basis.

There are many diagnoses and treatments of thoracic outlet syndrome. Please investigate the articles in this section to learn more about individualized cases from the files of Dr. Filler.

Open MR injection for Axillary Entrapment Diagnosis

Diagnosis: Using Open MR Injection to Confirm an Axillary Nerve Entrapment

Animated at right: Open MR injection for confirmation of the diagnosis of axillary nerve entrapment syndrome.

Pain and weakness in the shoulder is often due to a shoulder joint injury or to rotator cuff syndrome - an injury in which the muscles and ligaments around the joint are weakened or torn. However, in many cases, the actual cause of the problem is an entrapment of the axillary nerve. This condition causes weakness of the deltoid muscle making it difficult to raise the arm to the side. It also causes pain around the outer surface of the shoulder.

After confirming the tentative diagnosis by MR Neurography in a high field scanner, the patient goes to an Open MR system for an interventional diagnostic injection.

A titanium Lufkin needle (*) is advanced to a position adjacent to the area of the axillary nerve which was hyperintense on the Neurography study. Imaging in the Open scanner is by Flash T1 sequences which take about 10 seconds to acquire. The needle causes minimal artifact and appears as a black signal void in the image.

If the diagnosis is confirmed but the problem returns quickly, then the entrapment can be relieved by a small outpatient surgery. This diagnostic method and the treatments for this condition were developed by Dr. Aaron Filler at the Institute for Nerve Medicine.

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Injection of Anterior Scalene Muscle

Diagnosis: Open MRI Image Guided Injection of Anterior Scalene Muscle

Animation: Open MR image guided injection of the anterior scalene muscle.

In the coronal image (A), the arrow indicates a darkened area caused by the injectate within the anterior scalene muscle.

In the axial image (B), the titanium needle is seen passing into the anterior scalene muscle. The injectate has expanded the muscle, however the failure of injectate to flow in to the more posterior portions of the muscle suggests fibrosis within the muscle.

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