1. 2025;28;E509-E523Optimizing Pain Relief in Refractory Thoracic Outlet Syndrome: The Role of Ultrasound-Guided Injections
   Literature Review
   Helen Gharaei, MD, and Negin Gholampoor, MBChB.

BACKGROUND: Thoracic outlet syndrome (TOS) encompasses a range of symptoms originating  from the compression of neurovascular structures, often leading to significant morbidity. Neurogenic thoracic outlet syndrome (N-TOS) frequently manifests as brachial plexus neuropathy, with a subset of patients experiencing refractory pain that does not respond to conservative treatments.

OBJECTIVES: This review aims to consolidate current evidence to evaluate the efficacy of available ultrasound (US)-guided injection techniques, including muscle injections, hydrodissection, regenerative therapies, and nerve blocks, in managing refractory pain associated with N-TOS. Additionally, this study aims to provide clinical guidance for pain management in refractory TOS through current treatment strategies, offering structured guides that physicians can use as practical tools.

METHODS: A literature search was conducted across various academic databases to identify studies addressing US-guided interventions for refractory N-TOS. Relevant data regarding treatment efficacy, patient outcomes, and procedural details were extracted and synthesized narratively, as well as using structured tables and frameworks to aid in clinical decision-making.

RESULTS: US-guided injection techniques have demonstrated effectiveness in managing refractory pain that occurs after TOS surgery. Muscle injections, particularly botulinum toxin and local anesthetics, target muscle spasms, while hydrodissection alleviates nerve entrapment. Additionally, nerve blocks, such as epidurals and stellate ganglion blocks, provide targeted pain relief by addressing specific nerve pathways. However, although regenerative therapies, including dextrose prolotherapy and platelet-rich plasma (PRP), show great potential for tissue healing, they remain under research and available data on them are limited. 

LIMITATIONS: The effectiveness of these interventions may vary based on individual patient factors, practitioner experience, and the complexity of TOS presentations. Furthermore, while US-guided injections are well-established, the role of regenerative therapies requires further investigation due to a lack of standardized protocols and robust clinical trials, calling for future research.

CONCLUSION: US-guided injection techniques represent a promising approach for managing refractory pain in N-TOS, offering tailored pain relief strategies. However, ongoing research is essential to clarify the efficacy of regenerative therapies and to optimize treatment protocols, ultimately enhancing patient outcomes and quality of life.

KEY WORDS: Refractory thoracic outlet syndrome, pain relief, ultrasound-guided injections, nerve entrapment, muscle spasms, scar tissue, interventional pain management, regenerative therapies, brachial plexus, targeted interventions