Syncope Risk in Cervical Nerve Treatment: Case Report

A 41-year-old woman experienced a sudden, transient drop in consciousness 20 hours after undergoing a pulsed radiofrequency procedure for chronic neck pain and headaches. This event, diagnosed as vasovagal syncope, marks a newly documented complication for this generally safe neuromodulation technique, according to a case report published in the *Journal of Anesthesia and Clinical Research* by Kurnia Hendra Wijaya and Buyung Hartiyo Laksono.

A Delayed and Unexpected Reaction

The patient had a complex history of chronic pain and neurological symptoms, including cervical radiculopathy from a herniated disc, tension-type headaches, cluster headaches, and chronic spontaneous vertigo. She underwent bilateral pulsed radiofrequency treatment targeting the greater and lesser occipital nerves and the C3 and C4 dorsal root ganglia. The procedure itself, performed under light sedation with propofol and midazolam, was completed without any immediate issues.

Approximately 20 hours later, however, the patient developed an acute decrease in consciousness. Her Glasgow Coma Scale score, a standard measure of alertness, dropped to a nadir of 12 (indicating a moderately reduced level of consciousness). Her heart rate profile was consistent with a reflex vasovagal event, where the body overreacts to a trigger, causing a sudden drop in heart rate and blood pressure leading to reduced brain blood flow. Gradual spontaneous recovery occurred over seven hours, with her coma scale returning to a normal score of 15 and no lasting neurological deficit.

Proposed Mechanism: Triggering a Primitive Reflex

Wijaya and Laksono provide a pathophysiological explanation for this delayed event. Pulsed radiofrequency applies electromagnetic energy near specific nerves, modulating their activity. The authors suggest that afferent stimulation of the trigeminocervical complex—a network of nerves in the upper cervical spine and brainstem involved in head and neck pain—may have activated the Bezold-Jarisch reflex.

This reflex is a primitive, protective response originating in the heart. When certain cardiac receptors are stimulated, signals are sent to the brainstem, resulting in increased parasympathetic activity. This slows the heart rate and dilates blood vessels, which can cause a precipitous drop in blood pressure and lead to syncope. In a susceptible patient, the authors argue, the neuromodulatory effects of the procedure could have sensitized this pathway, leading to the delayed vasovagal episode.

Clear Therapeutic Benefits Amidst a Complication

Despite this adverse event, the therapeutic outcomes of the procedure were notably positive for several of the patient’s conditions. A comparison of her symptoms before and after the intervention showed clear improvement in cervical paraesthesia (abnormal sensations), vertigo, tinnitus, and cluster-type headache. This suggests the procedure effectively addressed part of her complex symptom profile. The tension-type headache, however, persisted at a similar intensity, indicating its mechanism may be distinct from the other improved symptoms. This outcome is relevant for patients and clinicians exploring neuromodulation approaches for tinnitus and related sensory disorders.

The improvement in vertigo and tinnitus following cervical nerve treatment also adds to a growing body of evidence linking cervical spine disorders and auditory-vestibular symptoms. It underscores the importance of a comprehensive diagnostic approach for patients presenting with conditions like chronic spontaneous vertigo.

Practical Implications for Patient Safety

This single case report does not change the overall safety profile of pulsed radiofrequency, which remains a low-risk intervention. It does, however, identify a new, rare, and temporally unexpected complication that clinicians and patients should be aware of.

The authors recommend several practical measures to mitigate risk:

• Multimodal Monitoring: Using equipment that tracks heart rate variability and blood pressure trends during and after the procedure could provide early warning signs.
• Adequate Hydration: Ensuring patients are well-hydrated before and after the procedure may help stabilize cardiovascular response.
• Careful Sedation Titration: The type and depth of sedation might influence autonomic nervous system stability and should be carefully managed.
• Structured Post-Procedural Observation: Since the event occurred 20 hours later, standard same-day discharge protocols may need to be supplemented with clear, written instructions for patients describing warning signs of vasovagal syncope and when to seek immediate medical attention.

For patients considering such procedures, this report emphasizes the importance of discussing all potential risks, even those that are rare and delayed. It also highlights that positive outcomes for conditions like tinnitus and vertigo are possible, as detailed in the source paper (Wijaya & Laksono, 2024). The management of complex, overlapping conditions often requires a multifaceted strategy, which can include neuromodulation alongside other approaches like sound-based therapies.

Conclusion: A Note of Caution for a Safe Procedure

The case documented by Wijaya and Laksono expands the known spectrum of adverse events for cervical pulsed radiofrequency to include delayed vasovagal syncope. While the procedure successfully treated several of the patient’s debilitating symptoms, the syncopal episode underscores that neuromodulation interacts with complex autonomic pathways. For clinicians, integrating specific monitoring and patient education strategies can help manage this newly identified risk. For patients, this report reinforces that a clear dialogue about both the benefits and the full range of potential complications is a necessary part of informed consent for interventional pain and neuromodulation therapies.