Standard Thoracic Outlet Syndrome Surgery

What are non-surgical treatment options for thoracic outlet syndrome?

When it comes to thoracic outlet syndrome, the most important step for successful treatment is establishing correct diagnosis. It sounds obvious but from practical standpoint it is the most important obstacle for cure. In some instances the border between diagnosis and treatment is blurry. For example, various injections can provide for both temporary relief and diagnostic confirmation.

Light cases are managed conservatively. Armrests, physical therapy, painkillers, breathing and stretching, postural exercises, injections maybe helpful. It is very important to find and eliminate the cause of disease for effective treatment. Very often these causes are anatomical and do not respond to conservative management.

Injections

In some patients, injections can provide temporary relief. There are two types of injections for TOS treatment – local anesthetic and Botox. These injections are usually performed under radiological guidance to ensure accuracy. Local anesthetics simply numb the area and suppress the pain. Their effect lasts only a few hours and by no means they provide lasting treatment. Botox injections on the other hand cause prolonged muscle paralysis. The effect lasts no more than 6 months. The positive response to local anesthetic or Botox injection is considered as a confirmatory diagnostic test. However, there is not much evidence to support this assumption. One study from USA, estimated the accuracy of Botox injections by analyzing surgical patients. Contrary to general assumption, this study found that diagnostic accuracy of Botox injections is very low. ¹

Physical Therapy

Physical therapy (PT) is the cornerstone of non-surgical treatment. However, PT usually is not helpful because it cannot eliminate underlying bone or soft tissue anomaly. As discussed, these musculoskeletal abnormalities comprise majority of TOS cases making physical therapy ineffective. The only one prospective randomized study found that surgery provides better results in comparison with physical treatment. ² 

Surgical Treatment

Because TOS develops due to anatomical abnormality (at least in the majority of cases) the surgery is the only way to permanently cure the disease. It aims to decompress the thoracic outlet area and hence is the name – thoracic outlet decompression (TOD). There are two categories or surgical treatment for TOS – without rib removal and with rib removal.

Anterior Scalenectomy and Neurolysis (rib-sparing technique)

This type of surgery is very common. However, it did not exist during early years of thoracic outlet syndrome surgery. Back then surgeons removed accessory and first rib for TOS treatment (as well as other, quite radical methods). Scalenectomy and neurolysis were first reported in 1927 as an alternative to rib resection. ³ The thing is there are several significant risks and complications associated with rib removal. That is why surgeons came up with less radical and allegedly safer approach. The main assumption was that soft tissue bands (not first or accessory rib bones) cause neuro-vascular compression. This assumption turned out to be wrong and many (but not all) surgeons abandoned scalenectomy and restarted rib resection. Others stuck with scalenectomy/neurolysis and the procedure has survived until today. To settle the debate, in 2005 a group of investigators conducted a prospective randomized trial (the only one up to this day). This study compared rib-resection and rib-sparing techniques and found that rib removal provides significantly better results. ⁴ The authors came to conclusion that “The major compressive element in patients with TOS-associated pain appeared to be the first rib (not soft tissue)”. Did this research change things? Not so much. It is unfathomable how an inefficient and harmful procedure is stubbornly in use today.

Proponents of rib sparing method argue that this technique has low complication rate. However, studies have found that generally complication rates are similar between rib-sparing and rib-resection techniques. For some specific complications rib-sparing technique carries more risk.

Surgical Technique

The procedure is carried out from the front. After exposing nerves and vessels surgeon detaches anterior scalene muscle from first rib attachment and removes its lower portion (scalenectomy). Then additional, visible soft tissue bands overlying or crossing the nerves are released (neurolysis). Optionally the middle scalene muscle can be cut as well. The method allows relatively broad exposure of nerves. But this impression is deceiving because exposure does not equate to treatment. It is underlying first and accessory ribs that cause compression. Regardless of surgical technique, thoracic outlet decompression is ineffective unless the surgeon removes first and accessory ribs. Most patients do not benefit from surgery, some worsen. Worsening is due to scar tissue growth around the nerves. Such fibrosis is harmful to nervous tissue and causes chronic debilitating neuropathic pain. The unfortunate thing about scar tissue is that it cannot be treated after it has established because further surgery to clean it up will just induce more fibrosis.

Overview of Rib Removal Techniques

First and accessory rib resection is the quintessence of successful thoracic outlet decompression. However, there is tremendous difference in the magnitude of rib resection among surgeons. Some surgeons merely touch the first rib while others pursue aggressive resection. There is overwhelming scientific evidence indicating that the scale of 1^st rib removal correlates with long-term success. Partial rib extirpation begets residual bone stumps. These bone fragments cause recurrence/persistence because they are the root of the problem and have never been addressed in the first place. Prominent thoracic outlet surgeons always emphasized the essentiality of rib resection. A conclusive study from Italy proved that the length of remaining rib stumps affects the surgical success. ⁵ These results were confirmed later, in 2014 from independent research group at John Hopkins University. ⁶

Basically, all high-quality studies indicate that in order to achieve good results the first rib should be removed as much as possible. We will return to this information below when discussing surgical techniques. This information is absolutely crucial, especially for those who are considering surgery for TOS. 

Anterior or Supraclavicular Approach

It is the most straightforward and oldest way to access the neuro-vascular bundle. The first ever reported surgery for thoracic outlet syndrome was performed via this route. ⁷ The technique has evolved over 150 years but the basics are the same. The procedure is very similar to anterior scalenectomy and neurolysis (see above). The only difference is partial first/accessory rib removal.

The surgeon approaches the brachial plexus and subclavian vessels from the front. Like with rib sparing technique brachial plexus can be readily and widely exposed. The first and accessory rib exposure and removal on the other hand is difficult and risky. Ribs’ deep location — literally under brachial plexus, subclavian artery, and vein hinders the access. To reach and remove the first rib, nerves and vessels should be moved away. But the nerves and vessels don’t like manipulation. Nerves are particularly sensitive to physical manipulation. Each nerve consists of hundreds or thousands of individual delicate microscopic nerve fibers. Their function is to carry neural impulses in the form of electrical action potentials. Any mechanical manipulation may inadvertently damage these fibers. Consequently patients may develop complications like paralysis, numbness and neuropathic pain. The pain is particularly debilitating.

Due to technical difficulties and complications surgeons remove only a small segment of the first rib. Usually it is the middle third of the first rib and tip of the accessory rib. Posterior and anterior first rib segments as well as majority (if not all) of the accessory rib cannot be safely reached and resected.

A recent large literature review from Japan analyzed the outcomes and complications of various surgical techniques. ⁸ They found that short term complete relief rate is only 57% and neurological injury rate is 3%. Also, there is small but real risk of vascular injury and death. Most studies analyzed in this review had relatively short follow-up time. Long follow-up studies show that success decreases and recurrence increases as time passes. Nearly quarter of patients do not benefit from surgery at all. This is known as persistence. Some of them get progressively worse due to soft tissue sagging into the gap between residual bones and increased tension on the nerves (“missing third” effect). As a result these patients’ symptoms worsen and they have to live in chronic debilitating pain.

Lateral or Transaxillary Approach

David Roos developed this method in 1966. ⁹ This techique is popular among thoracic surgeons. Surgeon exposes the first rib from the side and below, through armpit. To access the side of the first rib via this route surgeon must pass a long distance. Once the first rib is found the muscles are stripped from it while paying attention not to damage nerves and vessels passing over it. The rib is cut and removed.

There are several intrinsic problems of this technique. The arm should be moved away and held during the surgery. Usually one assistant’s sole functions is hold and move the arm during procedure. The wound is very narrow and deep requiring deep muscle retraction. Visibility is poor and surgical manipulation is fiddly. Sometimes the second rib obstructs the access and must be removed. Midportion of the first rib can be reached relatively easy. Anterior and posterior rib ends are hard to reach and remove (like with anterior supraclavicular approach). Accessory rib is also difficult to expose and resect. Brachial plexus is barely visible – only short segment of the lower trunk can be visualized. arterial TOS can be effectively treated with this approach. However, arterial cases comprise only small percentage of all TOS patients. Venous and neurogenic TOS variants are much more common and Therefore, vascular TOS (arterial and venous) can be effectively treated. The posterior portion of the first rib is very hard (but not impossible) to expose and remove with this approach. 

Literature review found 53% complete relief rate and 5% risk of neurological injury rate for transaxillary approach. ⁸ Again, there is small but real risk of vascular injury and death.

One of the major handicaps of transaxially approach is limited access to brachial plexus. Even if the entire first rib resection is performed, only a very limited (lower) portion of the brachial plexus can be visualized and decompressed. The surgeon cannot high up with this approach because the starting point is very low. Thus soft tissue compression cannot be resolved with type of surgery. 

Endoscopic assisted transaxillary approach

This type of approach is a slight modification of well-known standard transaxillary approach. The only difference is once the surgical corridor has been established an endoscope is inserted into the surgical cavity. The illumination and magnification provided by the endoscope allows better visualization not only for the surgeon but also for the entire operating team. This way everybody can see what is done making this method excellent for education and training.

Besides enhanced visibility and image sharing there aren’t many additional benefits of this method. All shortcoming associated with standard transaxillary approach are the same with endoscopic assisted technique. Success and complication rates are therefore very similar.

Video Assisted Thoracoscopic (VATS) and Robotic Approaches

These approaches are relatively new and based on a different surgical strategy. Rather than painstakingly getting the access to the first rib the surgeon uses normal chest cavity for easy access. The surgery starts with establishing several working channels. One of those channels is used for endoscope, others for surgical tools. The lung is collapsed to have ample space for surgical manipulation. This is the standard setup for nearly all thoracoscopic procedures. The first rib is at the top of chest cavity and the surgeon must access it from below. The rib is exposed and removed without disturbing nerves and the vessels. After rib removal the lung is re-inflated and surgical channels are removed. VATS and robotic approaches are very similar, the main difference is technical. In VATS surgeons stands at the operating table and holds the tools. During robotic surgery on the other hand the surgeon sits at the console and robot repeats his motions.

The main benefit of this approach is the ability to access and remove the first rib without vein, artery or nerve manipulation. It is a very important advantage because (as we discussed above) nerve and vessel damage is main complications of TOS surgery. However, there a very serious drawbacks of this technique. Firstly, only limited portion of the first rib can be removed. As we know, the amount of rib removal is directly proportional to long term success and remaining rib stumps lead to recurrence. The posterior segment of the first rib is not removed due to risk of neurological damage. Secondly, anything above the first rib cannot be exposed. Accessory rib, fibromuscular bands, aberrant vessels cannot be removed by using this technique. It is mostly useful for vascular TOS cases like venous or arterial compression.

Anterior Infraclavicular Approach

This approach is used exclusively for venous TOS. Surgeon approaches the first rib from incision below the collar bone. The rib is usually shallow and easy to expose. Only anterior segment of the rib can be reached and resected. Therefore, only subclavian vein can be decompressed. It is a good surgical choice for vTOS cases, including McCleery syndrome or Paget-Schroetter syndrome but not suitable for others. Neurogenic and arterial TOS cannot be treated from anterior infraclavicular approach.

Next: Persistent and Recurrent Thoracic Outlet Syndrome

References

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7. Coote. St. Bartholomew’s Hospital. Exostosis of the left transverse process of the seventh cervical vertebra surrounded by blood vessels and nerves. Successful removal. The Lancet. 1861;77(1963): 360-361. https://doi.org/10.1016/s0140-6736(02)44765-4[↩]
8. Suzuki T, Kimura H, Matsumura N, Iwamoto T. Surgical Approaches for Thoracic Outlet Syndrome: A Review of the Literature. J Hand Surg Glob Online. 2023;5(4): 577-584. https://doi.org/10.1016/j.jhsg.2022.04.007[↩][↩]
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