Introduction
Thoracic outlet syndrome is always managed with a course of non-operative treatment first. Targeted physiotherapy can ease the symptoms or result in complete cure in many cases. For those for whom physiotherapy does not relieve the symptoms, surgical decompression can be a good option.
Indications
There are two main approaches to the decompression of the thoracic outlet:
- First Rib Resection.
- Supraclavicular Decompression with Scalenectomy.
If the TOS is mainly vascular or seems to affect the lower nerves in the neck, then rib resection via the axilla is probably the best approach. This is generally performed by vascular surgeons and Dr Stewart works closely with several vascular surgeons with in interest in TOS.
For compression of the upper nerves, scalenectomy (removing a muscle in the neck that can press on the nerves) is more appropriate. In addition, a release of the tendon of the pectoralis minor muscle at the front of the shoulder can provide additional relief and is usually done in combination with scalenectomy.
Preoperative Instructions
TOS decompression is done under general anaesthetic and patients usually spend between 2 and 5 nights in hospital. Many patients with TOS have established chronic pain problems and will need specialized care from a pain physician while in hospital.
Procedure
For a supraclavicular decompression, an incision is made in the base of the neck and the nerves of the arm are dissected. The anterior scalene muscle is divided, and a portion removed while protecting the phrenic nerve which controls breathing and lies on the front of the muscle. Any additional structures compressing the nerves are released and the wound closed. Usually an additional incision is made on the front of the shoulder to release the tendon of pectoralis minor. In some situations, a combined procedure with a vascular surgeon will be organized to also remove the first rib through an incision in the axilla.
Postoperative Instructions
Patients stay for 2-5 nights after the surgery, and physiotherapy is started before discharge to make sure the nerves stay gliding freely in the neck and shoulder. Sometimes there can be some new weakness or numbness in the arm that takes several weeks to improve.
Risks
TOS decompression is major surgery and there are some risks involved. There is a small chance of a pneumothorax (collapsed lung) with could require a chest drain for several days. There is a small chance of loss of function of one of the nerves of the arm which could take several weeks to months to recover, and a very small risk of some permanent loss. This temporary nerve palsy can also affect the phrenic nerve, which results in some shortness of breath and reduced exercise tolerance.
Treatment Alternatives
Ongoing physiotherapy can provide some relief even when it does not cure thoracic outlet syndrome. Injections of botulinum toxin into some compressing muscles can in some cases be an alternative to surgical decompression.