Neurogenic Thoracic Outlet Syndrome

Neurogenic TOS is by far the most common type of thoracic outlet syndrome. Considering all patients with thoracic outlet syndrome, 1% suffer from arterial thoracic outlet syndrome and 2 to 5% suffer from venous thoracic outlet syndrome. The remaining 95 to 98% of thoracic outlet syndrome patients suffer from the neurogenic type of thoracic outlet syndrome. At the same time, diagnostic tests such as CT angiogram and ultrasound are readily available and reliable for the diagnosis of the arterial and venous types of thoracic outlet syndrome. Unfortunately, the clinical examination for neurogenic TOS, even with provocative tests, remains insensitive and inaccurate. Worse, the clinical diagnosis of neurogenic TOS does not demonstrate the underlying abnormal anatomy or pathology that causes the symptoms of neurogenic TOS.

Neurogenic TOS remains the most difficult type of thoracic outlet syndrome to diagnose. In the first place, patients experience a very broad range of signs and symptoms. The signs and symptoms of neurogenicTOS vary between different patients. Additionally, symptoms of neurogenic TOS vary over the course of a day, dependent on occupational and recreational activities and posture. At the same time, many doctors remain unknowledgeable about the disease, or are inexperienced in diagnosing patients with neurogenic TOS. The clinical diagnosis of neurogenic TOS challenges even the best thoracic outlet syndrome specialists, as clinical examination is based on unreliable non-anatomic provocative tests. Nonetheless, early diagnosis of neurogenic TOS makes a critical difference in treatment outcomes. As a result of the above challenges, modern imaging plays a vital role in confirming the diagnosis of neurogenic TOS and in demonstrating the underlying causes of neurogenic TOS.

Compression or tension on the brachial plexus causes the symptoms of neurogenic TOS. The brachial plexus arises from five nerve roots leaving the spinal cord of the neck. After leaving the spinal cord, these nerve roots exit the spine and form the brachial plexus within the thoracic outlet on each side. The brachial plexus is a large network of nerves that controls all motor and sensory function in each arm. When compression of the brachial plexus occurs, patients experience pain, sensory loss and weakness.

Symptoms of neurogenic TOS vary significantly between patients, and may vary over the course of a day within any single patient. Patients often experience sensory symptoms first. These include pain, numbness and tingling. Additionally, as the disease progresses, patients may note loss of coordination, or weakness of grip. Also, dysregulation of blood flow may cause temperature changes of the arm, hand or fingers.

Early and accurate diagnosis of neurogenic TOS likely improves the treatment outcome. Doctors often find a challenge when trying to diagnose neurogenic TOS on clinical examination alone. The clinical signs and symptoms of neurogenic thoracic outlet syndrome are often confusing and non-specific. However, an experienced TOS specialist knows how to use modern imaging tests like the NeoVista® MRI for the best imaging diagnosis of neurogenic TOS.

In general, treatment of neurogenic TOS aims to eliminate compression or tension on the brachial plexus. Most patients enter a conservative treatment protocol for 6 to 12 months. Specifically, conservative treatment may include breathing control and postural retraining, physical therapy, pain management and thoracic outlet syndrome exercises. However, if conservative measures fail, surgeons may remove the first rib, cervical rib, fibrous bands, and scalene muscles.