Neurogenic Thoracic Outlet Syndrome (NTOS)

This condition is the most common form of thoracic outlet syndrome. NTOS represents up to 90% of all TOS diagnoses.  Most commonly, the patient will presents with vague upper extremity, shoulder, and neck symptoms. 

Symptoms of Neurogenic Thoracic Outlet Syndrome

  1. Numbness and tingling in hands and fingers.
  2. Neck and shoulder pain.
  3. Neck muscle spasm.
  4. Headache on affected side.
  5. Color changes in finger tips on affected side.
  6. Mild swelling in hand on affected side.
  7. Chest pain on affected side.
  8. Symptoms worsened with overhead use of that extremity. 

 
ntos

NTOS illustration provided by G.Sheng MD, St.Vincent Medical Group.


Causes of Neurogenic Thoracic Outlet Syndrome

NTOS is caused by dynamic compression and irritation of nerves at the neck and shoulder level.  Deep muscles in the neck anterior scalene muscle and 1st rib form a narrowed space through which the brachial plexus passes through (outlined in green on the illustration below). This is one site where nerve and blood vessel compression typically occurs. 

Causes of NTOS 

  • Repetitive use of the arm and neck muscles (swimming, softball, baseball, and volleyball).
  • Injuries to the neck and shoulder area (whiplash, collarbone fracture, and shoulder injury).
  • Poor posture and shoulder instability can lead to the development NTOS.
  • Cervical rib or the congenital extra rib above the first rib.

 

Pectoralis Minor Syndrome (PMS) can present by itself in conjunction with NTOS. This condition is caused by compression of nerve fibers below the collarbone by a muscle called pectoralis minor muscle. Symptoms are similar to NTOS.

Diagnosis 

  1. Physical exam is the key for diagnosis of NTOS and PMS. Symptoms listed above are usually exacerbated by overhead activities and variety of challenged positions.
  2. Neck and chest x-rays are used to rule out the presence of an extra rib or cervical rib, as well as, fracture of first rib related to injury.
  3. Specific types of medical imaging studies are used to detect the compression of the vascular system in the shoulder and neck.
  4. Nerve conduction studies rule out other causes of nerve pain in neck and shoulder.
  5. A series of trigger point injections isolate the specific area of compression. By injecting the anterior scalene muscle with or without pectoralis minor muscles enables the vascular specialist to precisely identify the site of compression. This procedure is done within 10 minutes in our office with minimal discomfort.

 

Treating Neurogenic Thoracic Outlet Syndrome (NTOS) and Pectoralis Minor Syndrome (PMS)

Conservation treatment

Physical therapy is the initial treatment option for NTOS. It is important to work with physical therapists that are familiar with this condition. We have teamed up with physical therapists and chiropractors throughout the country to establish a care system for these patients. With effective physical therapy, 60 to 70% of NTOS and PMS patients are cured without further treatment.

BOTOX® injection (a neuromuscular blocker) in the trigger points related to the shoulder and arm nerve compression site can be extremely effectively in managing the debilitating symptoms of NTOS and PMS.  This procedure with insurance coverage is done as an outpatient in our facility. For more information about BOTOX see frequently asked questions.

Surgical Interventions

Surgical decompression of the entrapped nerve is reserved for those that fail to respond to conservative treatments for NTOS and PMS. This procedure is performed through a small incision above the collarbone. Scalene muscle and first rib are removed to achieve the most effective decompression. Pectoralis minor muscle resection can be performed at the same time or independently. This procedure usually takes 1 to 2 hours and the patient will typically recover in the hospital for 1 to 2 days. These vascular surgeons are very experienced in these advanced surgical techniques. Annually the TOS surgical team performs approximately 40 to 50 procedures with outstanding results. (Since, no complications or adverse events have been reported).For more information about the NTOS surgical procedure, see frequently asked questions.