Treatment of TOS
Surgical Treatment of Neurogenic TOS
Surgeons can take many different surgical approaches
Surgeons have developed a number of different approaches to enable decompression of the thoracic outlet. Each has advantages and disadvantages. While the details of each procedure are beyond the scope of this article, we feel it is helpful for patients to learn the basics of each, to empower their treatment choices.
Supraclavicular approach
Many surgeons currently prefer the supraclavicular approach to decompress the thoracic outlet. In the supraclavicular approach, the surgeon makes the primary incision just above the collarbone. He or she then dissects a thin muscle called the platysma and a fat pad until they are looking at the scalene triangle. At this point, the surgeon can directly view parts of the anterior and middle scalene muscle and the brachial plexus. The surgeon is able to remove the insertions of these muscles from the first rib, and then to remove a portion of the first rib. The surgeon is also able to remove scar tissue from the surface of the brachial plexus (neurolysis).
Advantages:
- The brachial plexus, scalene muscles, and surrounding soft tissues are accessible
Disadvantages
- The phrenic nerve, which controls the diaphragm (the muscle at the bottom of the chest that performs most of the work of breathing), is easily paralyzed if manipulated
- Removal of the anterior and posterior portions of the first rib is difficult through this approach.
Infraclavicular approach
Fewer surgeons use the infraclavicular approach. This approach has advantages and disadvantages compared to the supraclavicular approach. The surgeon makes the initial incision below the collarbone. The subclavian vein and the most anterior part of the first rib are readily visualized and accessible. The surgeon can resect the first rib from front to back until the brachial plexus is released. As the surgeon ‘walks back’ along the first rib, he or she can remove the insertion of the anterior scalene on the first rib to release it. However, the surgeon has limited access to most of the scalene muscles and brachial plexus.
Advantages:
- The subclavian artery and most anterior part of the first rib are accessible
- Less risk of damage to the phrenic nerve or to the brachial plexus
Disadvantages
- Limited access to the scalene muscles and brachial plexus
- Removal of the posterior portion of the first rib is difficult
Posterior approach
In the 1960’s, Dr. O. Theron Clagett, a widely-respected thoracic surgeon, proposed the posterior approach for surgical treatment of thoracic outlet syndrome. Conceptually, Clagett placed more emphasis on the rib as a cause of TOS, as opposed to the prevailing thought that the scalene muscles were the most significant cause. This procedure is technically quite challenging, but it does provide access to the proximal portion of each nerve root that makes up the brachial plexus. The procedure requires splitting or cutting several of the important muscles that support and move the scapula. For this reason, patients often experience significant weakness and limited motion of the scapula following surgery.
Advantages:
- Provides access to the proximal nerve roots leaving the cervical spine
- May be used if a prior surgery has created scar tissue in the anterior thoracic outlet
Disadvantages
- Significant side effects caused by approaching through the scapular muscles.
- Few surgeons have considerable experience with this approach
The image below demonstrates that the surgeon must navigate through several layers of periscapular muscles to reach the thoracic outlet. On the left side of the image is a superficial muscle, the trapezius, and on the right side a deeper layer of several muscles.
Transaxillary approach
Dr. David Roos pioneered the transaxillary approach in the 1960s. The surgical team positions the patient with the arm over the head. The surgeon makes a primary incision in the axilla, or armpit. Through this incision, the surgeon is quite close to the lateral aspect of the first rib. In addition, the surgeon can see the insertions of the anterior and middle scalene muscles, as well as fibrous bands and other soft tissue anomalies. The surgeon can resect the first rib in the anterior and posterior directions until the brachial plexus is released. He or she can also resect any fibrous bands or muscle anomalies. Surgeons who use the transaxillary approach feel it allows them access to the critical structures that compress the brachial plexus. However, other surgeons feel that the very small incision and deep surgical tunnel limits their view of the pertinent anatomy.
Advantages:
- Provides access to the first rib where brachial plexus compression is likely to occur
- Allows the surgeon to view most soft tissues of the scalene triangle, as well as soft tissue anomalies
- No disturbance of back, shoulder or chest muscles
Disadvantages
- Sustained and stationary overhead positioning of the arm in an unconscious patient may cause nerve palsies
- Limited resection of the anterior and posterior segments of the first rib
- Small and deep surgical tunnel limits visualization of anatomy
Combined approach
Surgeons know that each approach has advantages and disadvantages. Some surgeons have combined the supraclavicular and infraclavicular approach to create the combined approach. They feel that they gain important advantages, although the procedure requires a wider surgical field, and may take more time to complete.
Advantages:
- Provides access to both the anterior and lateral portions of the first rib
- Allows the surgeon to view most soft tissues of the scalene triangle, as well as soft tissue anomalies
- No disturbance of back or shoulder muscles
Disadvantages
- Sustained and stationary overhead positioning of the arm in an unconscious patient may cause nerve palsies
- Requires a wider surgical field, with increase cosmetic changes, and increased infection/other complication risks
- May require more time in the operating room
Different approaches have advantages and disadvantages
New Surgical Innovations
Each of the surgical approaches described above has advantages and disadvantages. However, surgery of the thoracic outlet should always be considered a major procedure. Thus, there are excellent surgeons around the country working on new and innovative approaches to the thoracic outlet. New surgical techniques aim to reduce operative time, increase safety margins, produce better results, reduce side effects, and decrease recovery time. Not every one of these goals can be accomplished with each innovation. However, surgeons continue to strive towards these goals.
Robotic Surgery
We believe that we are on the cusp of one of the most exciting innovations in thoracic outlet surgery. A number of pioneering thoracic outlet syndrome specialists are applying modern robotic surgery techniques to the challenges of thoracic outlet syndrome.
The Da Vinci Surgical System provides capabilities that no human hand can achieve. The system utilizes tiny laparoscopes, so the surgeon can see within tiny areas of the human body without requiring a large incision. The system also includes tools of various sizes, some of which are far smaller than a surgeon’s fingers. Not only can these tools reach areas that are inaccessible to the human hand, but they provide a range of motion no human can accomplish. Finally, the computer-assisted robot enables the surgeon with amazing precision and control.
Surgeons who are experienced with robotic surgery have found considerable success in shortening operative time, minimizing surgical complications, and improving outcomes, in addition to shortened recovery times.
Several recognized centers are pursuing the use of these tools in thoracic outlet syndrome:
Thoracic Robotic Surgery at UCLA
We have been privileged to hold many discussions with Dr. Farid Gharagozloo at the Global Robotics Institute. Dr. Gharagozloo is a pioneer in the use of robotic surgery of the thoracic outlet. We have been able to observe this surgery, and the procedure is eye-opening. Through a radical approach from beneath the first rib, Dr. Gharagozloo was able to remove nearly all of the rib. His technique protected the brachial plexus and phrenic nerve, yet completely mobilized the floor of the thoracic outlet. This results in an excellent decompression, allowing the brachial plexus and subclavian artery and vein to flow freely through the thoracic outlet.
Dr. Gharagozloo believes that our old concepts of thoracic outlet syndrome should be considered in a new light. Specifically, compression of blood vessels in the thoracic outlet, even in the absence of aneurysm or blood clot, causes persistent, low-grade swelling and reduction in oxygen to the soft tissues. In combination with relatively milder compression or tension of the brachial plexus, symptoms can result. Here is an excellent video introducing Dr. Gharagozloo’s ideas and technique. We are happy to work with Dr. Gharagozloo on imaging these patients, as well as moving the field of thoracic outlet syndrome forward with new concepts and understanding.
Microdissection without First Rib Resection
Most traditional surgical approaches to thoracic outlet syndrome focus on removal of a segment of the first rib. However, some surgeons are applying a different paradigm to the treatment of thoracic outlet syndrome. These surgeons believe that thoracic outlet syndrome represents a group of distinct diseases, with different mechanisms causing compression or tension of the brachial plexus within the thoracic outlet. In particular, these surgeons find some TOS patients with the traditional mechanism of brachial plexus compression between the first rib and clavicle. On the other hand, these surgeons also find patients without this traditional compression, but with compression or tension caused by fibrous bands, scalene anomalies, or brachial plexus anomalies. In these patients, surgeons perform careful soft tissue dissection and release of abnormal soft tissues. These patients do not require first rib resection. Specifically, this approach decreases the surgical complications, shortens the time in the operating room, and leaves the first rib in place as a structural strut.
Detailed MRI examination can provide exceptionally useful information prior to surgery in this group of patients. All of the pertinent soft tissues can be assessed in detail. Additionally, the absence of compression between rib and clavicle can be documented.
Modified Infraclavicular Approach
Most TOS surgeons are well aware of the limitations of the infraclavicular approach to thoracic outlet syndrome. Specifically, the infraclavicular approach limits access to the lateral aspect of the first rib, and to the scalene muscles and brachial plexus. However, one highly-experienced TOS surgeon has turned this conventional knowledge on its head. Dr. James Avery, in San Francisco, currently utilizes the infraclavicular approach in nearly all patients he treats for thoracic outlet syndrome. Dr. Avery has extensive experience performing the supraclavicular approach for decades. While the infraclavicular approach limits the surgeon’s approach to the scalene muscles, Dr. Avery has found this to be an advantage, rather than a limitation. He begins at the most anterior aspect of the first rib, then marches back along the rib. In this process, he frees up the subclavian vein, then the subclavian artery, and finally the brachial plexus, in sequence. When the brachial plexus is decompressed, Dr. Avery has hit his landmark.
Dr. Avery has found that procedure times are significantly shortened, recovery time in-hospital has been shortened, and patients undergoing this procedure experience the same results as those who previously underwent supraclavicular thoracic outlet decompression. These results create excitement in the TOS community.
Post-surgical Complications
Decompression of the thoracic outlet is a major surgical procedure. There are many vital structures coursing through a very small area, and the anatomy is quite complex. Additionally, many patients have unexpected variations of anatomy. Importantly, the first rib is quite stout and strong, so removing it requires significant effort. Finally, once the first rib is removed, a structural strut is no longer present.
Given these points, surgery of the thoracic outlet should always be considered a major procedure. As with any other major surgical procedure, serious complications may occur:
- Pneumothorax-An air leak around the lung, which may cause collapse of the lung.
- Chylothorax-The largest lymph vessel in the body, the thoracic duct, passes through the left thoracic outlet. Injury of the thoracic duct may cause chylothorax, and accumulation of lymph fluid around the lung.
- Infection-A risk factor of any surgical procedure.
- Bleeding-Injury to the subclavian artery or subclavian vein may cause major bleeding during surgery.
- Nerve Damage-The brachial plexus may branch and divide in complex, unpredictable ways. Thus, injury to the plexus remains a risk. Additionally, the small phrenic nerve passes anterior to each anterior scalene muscle. Even minor injury to the phrenic nerve may weaken or paralyze the diaphragm on the same side. This weakness or paralysis may significantly limit the ability to breathe. Often, this weakness or paralysis resolves by itself over several months.
- Brachial plexus inflammation or fibrosis-This is a complication that has not been well-described in the literature. However, we have seen many patients with thickening and swelling of the brachial plexus, as well as active inflammatory tissue surrounding the plexus. Since many surgeons perform neurolysis of the brachial plexus (stripping of scar tissue surrounding the plexus) during routine thoracic outlet decompression, there remains a concern that the procedure leads to this post-operative finding.
