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The nerve form of TOS

Neurogenic thoracic outlet syndrome (nTOS) concerns the brachial plexus, the nerve network serving the upper limb, in the thoracic outlet region. It is distinct from obstruction of the subclavian vein or injury to the subclavian artery. More than one form can be present, but a study of nerve symptoms does not establish treatment for vascular disease.1

The diagnosis can be difficult because pain, numbness and weakness overlap with other disorders. INTOS describes cervical spine disease and peripheral nerve compression among alternative explanations clinicians consider. Some patients have more than one problem. Recognizing overlap is different from attributing every upper-limb symptom to TOS.2

What specialist assessment brings together

History and examination identify the distribution and triggers of symptoms, local tenderness and functional changes. INTOS's modified SVS criteria combine local and peripheral findings with assessment of other reasonably likely diagnoses. Provocative maneuvers contribute to that assessment; they are not a stand-alone home test. Radiographs, MRI, ultrasound or electrodiagnostic studies may help address specific anatomical or differential questions. Their use varies by presentation and expertise.2

An electrically negative test result does not make all pain-based presentations identical. The newer 2026 INTOS case-scenario study includes pain/sensory presentations without electrical findings and presentations with distal nerve compression. Experts proposed different plans across the scenarios. It describes clinical judgment rather than a trial proving the best plan.3

Conservative care and reassessment

INTOS supports conservative management as an initial approach for many nTOS patients. This can include clinician-directed rehabilitation and management of contributing activities. Significant muscle weakness or wasting changes the surgical assessment context.2

A useful discussion identifies what improvement would look like, what functional limitations remain and when the team will reassess. Record the care actually received and the response rather than treating all “physiotherapy” courses as the same intervention. A change in the diagnosis or the pattern of symptoms may change the next question.

Surgical options and evidence

Decompression aims to relieve pressure on the nerves. Surgical choices may involve scalene muscles, a first or cervical rib, fibrous bands or an additional site of compression. The 2024 INTOS workgroup did not agree that first-rib removal should be routine in every primary nTOS operation. Anatomy and specialist interpretation matter.2

PURED, a posterior muscle-sparing approach developed by Dr. Kamran Aghayev, is one of these options. His published series of 61 patients with nTOS reported excellent or good improvement in all of them, with no permanent complications4. The treatment and PURED page describes the approaches and their evidence.

Prepare useful questions

Ask which findings support nTOS, whether another nerve-compression site could be contributing, what conservative care is intended to accomplish and how surgical benefits and harms will be measured. Ask who will coordinate follow-up if symptoms remain. These questions help explain a proposal without choosing it on your behalf.

References

  1. Illig KA et al. J Vasc Surg. 2016;64:e23–e35. doi:10.1016/j.jvs.2016.04.039. PubMed ↩
  2. Chim H, Hagan RR. Plast Reconstr Surg Glob Open. 2024;12:e6107. doi:10.1097/GOX.0000000000006107. Source ↩
  3. Chim H; INTOS Workgroup. J Hand Surg Am. 2026;51:982.e1–982.e9. doi:10.1016/j.jhsa.2026.03.014. PubMed ↩
  4. Aghayev K. World Neurosurg. 2023;180:e739–e748. doi:10.1016/j.wneu.2023.10.017. PubMed ↩