Neurogenic Thoracic Outlet Syndrome

Evidence: Limited / Insufficient Evidence — ASPN 2024: Level III · Grade I

CAUSES

• Compression of the brachial plexus nerves in the neck and shoulder
• An extra cervical rib
• Muscle hypertrophy or poor posture
• Repetitive overhead activity
• Whiplash

SYMPTOMS

• Pain, numbness, or tingling radiating into the arm and hand
• Weakness or heaviness in the arm with overhead activities
• Neck and shoulder discomfort accompanying the arm symptoms

IMAGING

A chest or cervical spine X-ray checks for an extra cervical rib. MRI or MR neurography of the brachial plexus and neck, along with nerve conduction studies (EMG/NCS), confirm nerve involvement and rule out other causes of arm symptoms.

CAN PRP HELP?

This diagnosis is fundamentally about nerve compression, not tendon or joint degeneration. Standard care (targeted physical therapy, nerve-gliding techniques, and surgical decompression for true refractory cases) remains the mainstay. PRP itself has essentially no controlled research behind it here, although there are case reports.

Leukocyte Preparation: Leukocyte-Poor, if pursued

Dosing: Not established

ASPN 2024 CONSENSUS GUIDELINE

ASPN grades this Level III, Grade I — evidence insufficient to judge. What the guideline supports with more confidence is ultrasound-guided hydrodissection (a saline or anesthetic injection to release perineural adhesion or scalene muscle tightness) for refractory neurogenic TOS; PRP or platelet releasate as the injectate for that same technique is described only in isolated case reports, without a standardized protocol. The guideline also flags a practical pearl worth checking first: rule out a coexistent, more distal nerve entrapment (such as at the elbow) before attributing all arm symptoms to the thoracic outlet.

Sources: D’Souza et al. (ASPN Consensus), Journal of Pain Research, 2024 · Gharaei & Gholampoor, Pain Physician, 2025 · Bejarano & Clearfield, Cureus, 2023

FREQUENTLY ASKED QUESTIONS

Is thoracic outlet syndrome a joint or tendon problem the way most of this guide’s other conditions are?

No, this diagnosis relates to nerve compression, as the nerves of the brachial plexus get compressed passing through the narrow space between the collarbone and first rib. This can cause pain, numbness, or weakness radiating into the arm rather than joint or tendon degeneration.

What’s hydrodissection, and is that the same thing as a PRP injection?

Hydrodissection is a saline or anesthetic injection used to release adhesions or tight scalene muscle around an entrapped nerve. ASPN supports this technique with more confidence. PRP used as the injectate for that same technique is described only in isolated case reports without a standardized protocol, which is why this indication is graded Level III, Grade I, which is evidence insufficient to judge.

What should be ruled out before assuming thoracic outlet syndrome is causing arm symptoms?

Ideally, we would work to rule out a coexistent, more distal nerve entrapment by an EMG/Nerve conduction study before attributing all arm symptoms to the thoracic outlet.