49th Annual Regional Anesthesiology and Acute Pain Medicine Meeting

Diagnostic Nerve block of Arnold’s Nerve, Auricular Branch of the Vagus Nerve, for Refractory External Auditory Canal Pain

Christian R. Perez, M.D., Fernando Vazquez, M.D., Christopher Chiang, M.D.

Directed nerve block of Arnold’s nerve resulted in subjective analgesia of unique auricular pain

Adequate pain relief from the block can serve as diagnostic precursor for subsequent treatment modalities

INTRO

•Cranial nerve X, the vagus nerve, contains both sensory and motor fibers

•Key role in parasympathetic control

oCardiovascular: heart rate

oRespiratory: phonation and airway protection

oGastrointestinal: swallowing and peristalsis

•Sensory coverage of ear via Arnold’s nerve, the auricular branch of the vagus, both inner auditory canal and external auditory meatus

•Otalgia can be a presenting sign of vagus nerve compression and may be difficult to treat

CASE REPORT

•57 y.o. male with subglottic squamous cell carcinoma complaining of persistent bilateral ear pain

oCancer treated with neoadjuvant chemo-radiation and tracheostomy for recurrent and progressive disease with plan for laryngectomy with free flap reconstruction after new discovery of FDG-avid lymph nodes

•Pain rated 8/10, constant, throbbing, localized to external acoustic canals bilaterally

oPain refractory to PO and IV analgesia, only reported relief was cutaneous simulation via gauze in canal

•Physical exam elicited no specific triggers, tympanic membranes were clear, and imaging showed no focal mass compression

•Patient underwent diagnostic nerve block of Arnold’s nerve after site preparation with alcohol

oUtilized 27-gauge needle and infiltrated 0.5cc of 1% lidocaine to subcutaneous tissue posterior to tragus, bilaterally

oNo complications noted

•Immediate pain relief, decreasing pain score to 3/10, lasting 1.5 hours with recurrence of preprocedural pain score

•Patient refused follow-up procedures / alternatives i.e. denser block, scheduled blocks, ablation, etc.

DISCUSSION

•Patient experienced excellent analgesia of bilateral auditory canal pain, however, refused therapeutic nerve block options or other alternatives

oUltimately chose to self administer 5% topical lidocaine to area three times a day and place cotton gauze in canal opening

•Vagus nerve and its branches can be affected by numerous pathologies, focally and diffusely

oOncological pain can be difficult to treat, either as localized or referred pain

•Growing field utilizing the auricular branch of the vagus nerve to treat other pathologies

oAtrial fibrillation

oDepression

oOpiate withdrawal symptoms

•Diagnostic nerve blocks of Arnold’s nerve can be useful in preparation for sustainable long term therapeutic interventions

oRepeated nerve blocks of increased intensity

oAblation

oNeuromodulatory techniques

REFERENCES

1.Tekdemir I, Aslan A, Elhan A. A clinico-anatomic study of the auricular branch of the vagus nerve and Arnold's ear-cough reflex. Surg Radiol Anat. 1998;20(4):253-7. PMID: 9787391.

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2.Canning BJ. Anatomy and neurophysiology of the cough reflex: ACCP evidence-based clinical practice guidelines. Chest. 2006 Jan;129(1 Suppl):33S-47S. doi: 10.1378/chest.129.1_suppl.33S. PMID: 16428690.

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3.Chen RC, Khorsandi AS, Shatzkes DR, Holliday RA. The radiology of referred otalgia. AJNR Am J Neuroradiol. 2009 Nov;30(10):1817-23. doi: 10.3174/ajnr.A1605. Epub 2009 Oct 1. PMID: 19797791; PMCID: PMC7051282.

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4.Yu L, Scherlag BJ, Li S, Fan Y, Dyer J, Male S, Varma V, Sha Y, Stavrakis S, Po SS. Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve: a noninvasive approach to treat the initial phase of atrial fibrillation. Heart Rhythm. 2013 Mar;10(3):428-35. doi: 10.1016/j.hrthm.2012.11.019. Epub 2012 Nov 24. PMID: 23183191.

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5.Dicpinigaitis PV, Enilari O, Cleven KL. Prevalence of Arnold nerve reflex in subjects with and without chronic cough: Relevance to Cough Hypersensitivity Syndrome. Pulm Pharmacol Ther. 2019 Feb;54:22-24. doi: 10.1016/j.pupt.2018.11.003. Epub 2018 Nov 13. PMID: 30445192.

49th Annual Regional Anesthesiology and Acute Pain Medicine Meeting

DIAGNOSTIC NERVE BLOCK OF ARNOLD'S NERVE, AURICULAR BRANCH OF THE VAGUS NERVE, FOR REFRACTORY EXTERNAL AUDITORY CANAL PAIN

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