From the Guidelines
Diagnosing neurogenic thoracic outlet syndrome (nTOS) requires a comprehensive approach combining clinical evaluation, physical examination, and diagnostic testing, with MRI being the most appropriate initial imaging modality due to its ability to delineate extravascular anatomy and characterize soft tissues 1. The diagnosis begins with a thorough medical history focusing on symptoms such as pain, numbness, or weakness in the arm, hand, or fingers, particularly when the arm is elevated.
- Physical examination should include provocative maneuvers like the Adson test, elevated arm stress test (EAST), and the Roos test, which reproduce symptoms by compressing the neurovascular bundle.
- Nerve conduction studies and electromyography can help identify nerve compression, though they may be normal in some cases.
- Imaging studies such as MRI, CT scans with 3D reconstruction, or chest X-rays can visualize anatomical abnormalities like cervical ribs or fibrous bands.
- Vascular studies including duplex ultrasound may rule out vascular forms of TOS.
- A diagnostic lidocaine injection into the anterior scalene muscle that provides temporary relief can support the diagnosis. It's essential to exclude other conditions with similar presentations such as cervical radiculopathy, peripheral nerve entrapment, or shoulder pathology, as noted in the American College of Radiology Appropriateness Criteria for thoracic outlet syndrome 2. The diagnosis often requires evaluation by specialists including neurologists, vascular surgeons, or thoracic surgeons with experience in TOS, as this condition can be challenging to diagnose definitively and frequently requires a multidisciplinary approach, highlighting the importance of understanding the various anatomic spaces and causes of narrowing in TOS 3.
From the Research
Diagnostic Criteria for Neurogenic Thoracic Outlet Syndrome
To diagnose neurogenic thoracic outlet syndrome (NTOS), several key components are considered:
- A thorough history and physical examination to identify symptoms such as upper extremity sensorimotor symptoms, paresthesia, pain, and weakness, as well as neck pain and occipital headache 4, 5, 6
- Stress maneuvers, including neck rotation, head tilting, and the upper limb tension test, to elicit symptoms in the contralateral extremity 4, 6
- Diagnostic and therapeutic imaging, such as MR neurograms with tractography, to confirm the diagnosis and identify the location of nerve compression 7
- Assessment of disability using standardized patient-centered instruments to evaluate the impact of NTOS on patient health-related quality of life 4
Diagnostic Challenges
Diagnosing NTOS can be challenging due to:
- Nonspecific symptoms and lack of definitive diagnostic testing 4, 8
- Overlap with other complex pain and entrapment syndromes 7
- Limited availability of multicenter randomized controlled trials on the treatment of NTOS 5
- Variability in surgical management approaches, depending on the experience and preference of the surgeon, treating specialty, special anatomic features, and clinical symptoms 5
Imaging Techniques
Imaging techniques, such as high-resolution MRI and tractography, can aid in diagnosing NTOS by: