Stellate ganglion block, or SGB, involves injecting a local anesthetic near the stellate ganglion, a cluster of sympathetic nerve cells located in the neck. The goal is to modulate autonomic nervous system activity, and the technique has a long history in pain management and certain circulatory disorders. More recently, it has been investigated as an option for patients with stubborn insomnia who have not responded to conventional treatments. The appeal is understandable: the procedure is minimally invasive, can be performed on an outpatient basis, and some studies suggest it may improve sleep quality and overall well-being in selected patients. But as this case demonstrates, the neck is a crowded anatomical neighborhood, and needles placed near the sympathetic chain sit close to structures that the body cannot easily spare.

The patient in question had endured six months of severe insomnia before arriving at the clinic. She was sleeping roughly four hours a night, taking about ninety minutes to fall asleep, and waking four to five times nightly. Standardized questionnaires confirmed moderate-to-severe chronic insomnia: her Pittsburgh Sleep Quality Index score was 16 and her Insomnia Severity Index score was 21. She had already tried sleep hygiene education, the sedative estazolam, and melatonin with limited benefit. Her medical history included well-controlled hypertension but no cervical spine disease, trauma, or neurological disorders. Neurological examination and cervical MRI before the procedure were normal, and she showed no clinical features suggesting sleep apnea or other sleep-related movement disorders. With conservative options exhausted, her care team proceeded with a right-sided stellate ganglion block.

The procedure itself followed the modern playbook. An experienced anesthesiologist used a high-frequency linear ultrasound transducer to visualize the anatomy at the level of the sixth cervical vertebra, identifying the carotid artery, internal jugular vein, thyroid gland, and the longus colli muscle before advancing a 22-gauge needle from the side in real time. Color Doppler imaging confirmed that no vessels lay along the planned trajectory. After negative aspiration for blood and cerebrospinal fluid, the physician slowly injected 3 milliliters of 0.2 percent ropivacaine combined with 1 milliliter of compound betamethasone, a corticosteroid added to prolong the block’s effect and dampen local inflammation. Throughout needle advancement and injection, the patient reported no radiating pain, tingling, or weakness — and the injection was completed as planned.

Then, roughly one minute after the needle was withdrawn, everything changed. The patient suddenly reported severe, electric shock-like pain radiating from her right shoulder down the lateral aspect of her upper arm, followed by weakness in shoulder abduction and elbow flexion. Because the symptoms appeared only after the injection had finished, there had been no opportunity to halt the procedure in response to warning signs. Two hours later, examination revealed Medical Research Council grade 3 out of 5 strength in the right deltoid and biceps muscles, reduced pinprick sensation over the lateral upper arm in the C5 dermatome, and a diminished biceps tendon reflex. Emergency cervical MRI ruled out disc herniation, hematoma, or any other compressive lesion that could explain the sudden deficit.

Three days after the procedure, with symptoms persisting well beyond the expected duration of the local anesthetic, electromyography was performed. The results showed abundant spontaneous electrical activity — fibrillation potentials and positive sharp waves — along with markedly reduced recruitment in the deltoid and biceps, muscles predominantly supplied by the C5 nerve root. Critically, sensory nerve action potentials were preserved, a pattern that points toward a preganglionic nerve root lesion rather than an injury to a distal peripheral nerve. The authors were careful to note, however, that the clinical picture of deltoid and biceps weakness also overlaps with partial involvement of the upper trunk of the brachial plexus, and because the patient declined dedicated brachial plexus MRI and no repeat electromyography was available, definitive anatomical localization remained out of reach. The findings were therefore interpreted as favoring C5-predominant involvement rather than proving an isolated root injury.

The mechanism of injury remains uncertain, and the authors are candid about that limitation. Real-time ultrasound never provided unequivocal evidence of an intraneural or intrafascicular injection, and the stored images, being static snapshots, could not confirm that the needle had penetrated a specific neural structure. Inadvertent needle-to-nerve contact, unintended perineural or limited intraneural spread, and injection-related neural irritation all remained plausible explanations. Previous MRI research has shown that even small-volume injectate can distribute across vertebral levels from roughly C5 to T1, lending anatomical plausibility to the idea that the solution reached nerve root territory, though the authors stress this evidence supports only possibility, not proof of what happened in this patient. The role of the betamethasone additive is likewise unclear; its use was extrapolated from other regional anesthesia settings, and direct evidence for corticosteroid adjuncts in SGB for insomnia remains thin.

The recovery trajectory offers a measure of reassurance. Treatment with neurotrophic support — mecobalamin and vitamin B1 — combined with physical therapy, including ultrashort-wave therapy and medium-frequency electrical stimulation, began promptly. Pain on a 10-point visual analogue scale fell from 8 at onset to 3 at two weeks and 1 at three months. Muscle strength in the deltoid and biceps improved from grade 3 to grade 4+ out of 5 by the three-month follow-up, sensory abnormalities had largely resolved, and, somewhat remarkably, the patient’s insomnia symptoms had also improved. Still, the absence of repeat electromyography and validated functional outcome measures means the full extent of electrophysiological recovery could not be objectively characterized.

What makes this case resonate beyond a single patient is the broader context. C5 and C6 nerve root injuries have been described after cervical spine surgery and nerve root injections, but C5-predominant neurological injury following SGB performed for a sleep disorder has rarely, if ever, been documented. As SGB attracts growing interest for psychiatric and sleep-related indications — including post-traumatic stress disorder and menopausal insomnia — the population of patients exposed to the procedure is expanding well beyond the pain clinics where it was first refined. The authors argue that neurological complications may become apparent only after the block is complete, even when patients report no warning symptoms during needle placement, which means vigilance cannot end when the needle comes out. They recommend continuous needle-tip visualization, careful puncture route selection, avoidance of excessive depth, conservative injection volumes, and consideration of alternative approaches such as the anterolateral cervical technique, which may reduce nerve root exposure in selected cases.

For patients considering SGB for insomnia, the message is not that the procedure should be abandoned, but that informed consent should include an honest discussion of neurological risk, however uncommon. New radiating pain, focal weakness, sensory loss, or reflex asymmetry after any such block should trigger immediate neurological examination, appropriate imaging, and electrophysiological testing. As a single case report, the findings cannot be generalized — anatomical variation, comorbidities, and injection characteristics all influence individual risk. But the case stands as a vivid reminder that even ultrasound-guided procedures performed by experienced hands under ideal imaging conditions can produce serious complications, and that the expanding off-label use of regional anesthesia techniques demands the same rigorous safety standards, standardized training, and post-procedural monitoring applied in their original clinical homes.

Subject of Research: Suspected C5 nerve root injury temporally associated with stellate ganglion block for refractory insomnia

Article Title: Suspected C5 Nerve Root Injury Temporally Associated With Stellate Ganglion Block for Refractory Insomnia: A Case Report

Article References: Ji, X., Niu, Z., & Wang, Y. (2026). Suspected C5 Nerve Root Injury Temporally Associated With Stellate Ganglion Block for Refractory Insomnia: A Case Report. Clinical Case Reports, 14(10), Article e73603. https://doi.org/10.1002/ccr3.73603

Image Credits: AI Generated

DOI: 10.1002/ccr3.73603

Keywords: stellate ganglion block, C5 nerve root injury, refractory insomnia, ultrasound-guided injection, electromyography, regional anesthesia, neurological complications, ropivacaine, brachial plexus, patient safety, case report, autonomic nervous system