April 14, 2026
Thoracic outlet syndrome (TOS) — nerve compression in the thoracic outlet — relies on a diagnosis of exclusion and a coordinated approach to treatment. Neurogenic TOS, which accounts for 90% of all TOS cases, is especially challenging to diagnose. Premature diagnosis of TOS and unnecessary surgical interventions can lead to increased health risks and frustration for the patient.
"The majority of patients we assess for TOS are already deep into their diagnostic journey," says Sam Farres, M.D., division chair for Vascular Surgery at Mayo Clinic in Jacksonville, Florida. "They already know about and suspect thoracic outlet syndrome, but that doesn't necessarily mean they have TOS. It's important to rule out all potential causes of the symptoms before considering it might be neurogenic TOS. By thinking of thoracic outlet syndrome that way, you can achieve better patient outcomes."
Coordinated and rigid diagnostic protocol for neurogenic TOS
Neurogenic TOS involves brachial plexus compression, which can cause a wide range of symptoms, typically affecting the shoulder, arm or hand. Physical exams and imaging tests can help diagnose the condition and identify potential areas of compression, but pinpointing the exact reason for compression is a challenge — and critical for effective treatment.
To rule out other conditions, Mayo Clinic's core thoracic outlet care team for neurogenic TOS performs a comprehensive diagnostic workup that includes:
- X-ray of cervical spine and chest.
- Provocative CT angiogram or MRI.
- Electromyography.
- Peripheral neurology consultation.
- Physical medicine and rehabilitation consultation.
- Physical therapy referral.
Depending on the constellation of symptoms, the team may consult with additional specialists. "If there's a frozen shoulder element, we'll bring in a shoulder expert. If we suspect brachial plexus dysfunction, we consult with our brachial plexus expert. Patients with suspected hypermobility are referred to our hypermobility clinic for genetic testing," Dr. Farres says. "Diagnosing TOS can get very complex, very quickly. Care can be fragmented and time-consuming if you don't have these specialists all in one place. What might otherwise take months can be accomplished in days here."
Dr. Farres says the natural inclination is to assume the symptoms point to TOS and surgically resect the first rib to decrease compression. But without thoroughly ruling out other diagnoses, you might not be treating the root cause of the symptoms.
"A conservative approach really helps patients who don't have TOS," Dr. Farres says. "They expect to be diagnosed with TOS, but we determine that they have something rare going on and can treat them appropriately. That's just as much of a win as diagnosing and treating TOS."
Comprehensive expertise and treatment for neurogenic TOS
Once a neurogenic TOS diagnosis is confirmed, multiple treatment pathways are available depending on the severity of the symptoms and underlying condition. First line treatment is typically physical therapy. Other conservative measures, including medicines and anesthetic, steroid or onabotulinumtoxinA injections, also can be effective. Surgery is another option, but Dr. Farres says it comes with higher risks and is not always indicated. A collaborative approach to care ensures the treatment pathway is personalized.
"A multidisciplinary approach brings varying expertise and perspectives together and provides checks and balances," Dr. Farres says. "We are equal partners in establishing the treatment plan and all want the best solution for the patient."
When indicated, surgery for neurogenic TOS is a complex procedure that involves removing the first rib. The operation — performed using open or robotic surgery — may require navigation and dissection of bony structures, major arteries and the brachial plexus before disconnecting muscles from the rib and removing it. The procedure requires advanced expertise and should not be rushed into.
"The best way to approach TOS treatment is to imagine it as a tree with branches that overlap," Dr. Farres says. "Someone with neurogenic TOS may need physical therapy to start. Later, they may need injections. If their pain and compression escalate, they may need surgery. Other patients may need to start with surgery. Either way, we have specialists weighing in at every step."
Improving TOS surgery and patient experience
For some patients with neurogenic TOS, surgery provides the best treatment option. Mayo Clinic physicians are conducting research to improve surgical techniques and reduce postoperative pain to enhance the patient experience. Their interests include:
- Paravertebral block. Dr. Farres is the principal investigator for a clinical trial studying the effect of paravertebral blocks on patients undergoing TOS surgery. The interventional study will assess how paravertebral blocks administered at one day, three days, seven days and two weeks post-op affect a patient's quality of life, function and pain level. TOS surgery can be incredibly painful. The current standard of care is intravenous or oral pain medication.
- Robotic techniques for TOS surgery. Surgeons use robotic assistance whenever possible for TOS surgery, but they are experimenting with different ways to use the robot to accomplish the first rib resection.
"Our goal is to help people with neurogenic TOS pinpoint the problem and find relief in the most conservative way possible," Dr. Farres says. "If surgery is indicated, we're working to help patients recover faster, go home earlier and have a better postoperative experience."
For more information
Clinical trials: Thoracic outlet syndrome pre-operative and post-operative paravertebral block. Mayo Clinic.
Refer a patient to Mayo Clinic.