The Vertebral Nerve as a Selective Target for Upper Limb Sympathetic Blockade: Anatomy, Ultrasound‐Guided Technique, and Proof of Concept

The vertebral nerve (VN) is a postganglionic sympathetic structure that arises from the cervicothoracic ganglion, ascends alongside the vertebral artery, and provides sympathetic innervation to the upper limb via the brachial plexus. Despite its anatomical relevance, it remains largely unknown to anesthesiologists and pain clinicians. The stellate ganglion block (SGB) is the current standard for upper-limb sympatholysis but produces nonselective effects, including Horner's syndrome and potential cardiac involvement. A more selective approach targeting the VN could achieve equivalent upper-limb sympatholysis while potentially offering a superior safety profile. We conducted a comprehensive anatomical review of the VN, covering its origin, trajectory, branching patterns, and communications with both the cervical spinal nerves and the vertebral plexus. Using this anatomical framework, we describe an ultrasound-guided technique for selective VN blockade at the C7 level, validated with fluoroscopic contrast confirmation. We objectively evaluated clinical efficacy using infrared thermography and laser Doppler flowmetry. The VN is an anatomically consistent and sonographically accessible target for selective upper-limb sympathetic blockade. At this target, effective sympatholysis can be achieved with minimal injectate volumes, thereby avoiding the nonselective effects of conventional SGB. Further studies are needed to compare efficacy, optimal technique parameters, and complication rates with existing approaches.