COMMENTARY

Diagnosing and Treating Thoracic Outlet Syndrome

Justin M. Brown, MD

Disclosures

August 31, 2011

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My name is Dr. Justin Brown at the University of California, San Diego, Division of Neurosurgery. I am a peripheral nerve specialist. Today, I want to discuss thoracic outlet syndrome, specifically neurogenic thoracic outlet syndrome.

Thoracic outlet syndrome is referred to as a pain syndrome that generally involves the upper extremities. When a patient presents with these symptoms, people most commonly think of a cervical rib, which we evaluate for with a chest x-ray. However, cervical rib syndrome is probably one of the rarer forms of neurogenic thoracic outlet syndrome. The majority of patients who present with these pains and symptoms come with a shoulder-forward, hunched posture that seems to be exacerbated by a particular work situation.

Diagnosing thoracic outlet syndrome can be very puzzling because there are a number of pain sources in this syndrome. There are pains from the muscle imbalance that has contributed to this posture. They can be pains through the upper back or through the neck. There are also pains related to neuritis, or the irritated nerves that occur within the neck. Pain can also be contributed to by compression at the neural frame and in the cervical spine, at the cubital tunnel, and the carpel tunnel. There tends to be a continuum of compressions throughout the upper extremity.

When addressing these entities, it is important to establish what the cause of the disorder is. If the cause is acute trauma, such as a whiplash injury or an obstetric brachial plexus palsy, there is often scar tissue buildup and it will need to be addressed surgically. Nonetheless, the patient should be addressed by a physical therapist first. You need to see if the postural problems can be corrected. We can bring the shoulders back into the proper position, stretch the scalene muscles, and eliminate some of the contributing postures and positions that the patients are assuming throughout the day that are exacerbating the situation. I would say that the vast majority of our patients are able to be significantly alleviated, or even cured, by proper physical therapy.

When a patient comes in with this set of symptoms, our primary means of making a diagnosis is not electromyography or electrodiagnostic studies but the physical examination. The reason for this is that the nerve pain in thoracic outlet syndrome is primarily a neuritis, a nerve inflammation. It is an irritation of the nerve that occurs dynamically when the nerve is being compressed, and it often does not result in axon loss or reduced conduction or things that are obvious on electromyography studies. One of the pathognomonic features of thoracic outlet syndrome is that when patients raise their arms in the air for a period of time, they immediately elicit the symptoms -- they have excruciating pain in the neck, radiating out to the arms. This is alleviated by putting the arms back down at the sides.

We also go through an examination of each of the entrapment points, compressing the wrist over the carpel tunnel, compressing the elbow over the cubital tunnel, placing pressure over the thoracic outlet itself, and then attempting Spurling's maneuver by closing the neural frame. The site from which the majority of pain is elicited is usually the primary source. Placing the thumb over the scalene muscles and applying some pressure usually causes a complete recreation of symptoms down into the extremity.

Patients are then referred to physical therapy. They go through a number of exercises to stretch the scalenes and nerve mobilization exercises to mobilize the nerves through the cubital and carpel tunnels. If there is a significant component of ulnar neuritis, we place them in elbow pads and teach them to sleep with their arms straight to alleviate this. After significant therapy, if the patient's symptoms either persist or worsen, we proceed to surgery.

Surgery is focused on the primary source of symptoms. Sometimes a patient with thoracic outlet syndrome will also have a significant contribution from the ulnar nerve at the elbow. In this case, we will often decompress the ulnar nerve alone and then refer the patient back to therapy, and we have had success with this. At times, the thoracic outlet itself causes 90% of the symptoms, in which case that will need to be decompressed directly. We found that decompression of the thoracic outlet generally involves resecting the scalene muscles in the neck. Although many centers feel that it is important to remove the first rib, we think that it is important to leave the rib in place if it is not anatomically abnormal. It reduces morbidity of the procedure, postoperative pain, and recovery time if the rib is not removed. Therefore, we make a small incision in line with the clavicle. Then we dissect, preserving the supraclavicular nerves. We lift the fat pad out of the way, find the scalene muscles, and transect them with bipolar electrocautery. At the end of this procedure, we are able to see that the nerves are free and there is no compression on them. We close, inject local lidocaine, and the patient stays overnight and is discharged the next day.

This will end our segment today discussing thoracic outlet syndrome. Again, this is Justin Brown, and I thank you for listening.

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