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Original research
Greater occipital nerve block modulates nociceptive signals within the trigeminocervical complex
  1. Jan Hoffmann1,2,
  2. Jan Mehnert1,
  3. Elena M Koo1,
  4. Arne May1
  1. 1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
  2. 2Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
  1. Correspondence to Arne May, Systems Neuroscience, University Hospital Hamburg Eppendorf Clinic and Department of Neurology, Hamburg 20246, Germany; a.may{at}uke.de

Abstract

Introduction The pharmacological block of the greater occipital nerve has been proven effective in numerous headache and facial pain syndromes. This clinical effect supports the hypothesis of a strong functional interaction between the occipital and trigeminal nerves which has been proposed in neurophysiological in vivo experiments in rodents. Although it is likely that the interaction has to occur in the central nervous system, the exact site and the mechanisms of the interaction remain largely unknown.

Methods Focusing on these questions we investigated in a double-blind, placebo-controlled, randomised study the influence of an occipital nerve block with lidocaine 1% on neuronal activation in the trigeminocervical complex using high-resolution functional magnetic resonance on a 3T scanner. In order to investigate potential clinical effects on the trigeminal nerve, we further performed quantitative sensory testing and analysed a potential shift in thermal detection and pain thresholds.

Results The pharmacological block of the greater occipital nerve induced an occipital anaesthesia ipsilateral to the block. Functional imaging revealed that the occipital injection of lidocaine but not placebo significantly reduced nociceptive trigeminal activation.

Conclusions These data suggest that the functional inhibition of the occipital nerve block on trigeminal nociceptive activity is likely to occur at the C2 level where the occipital nerve enters the trigeminocervical complex and converges on the same central nuclei before the signal crosses the midline at that level and is then transmitted to higher processing centres.

Data availability statement

Data are available upon reasonable request. All patients who participated in this study gave written informed consent. However, this consent did not include a provision stating that individual raw data can be made freely accessible to the public. Therefore, in accordance with the German data protection act §4 the underlying raw data cannot be made accessible to the public. Researchers meeting the criteria for access to confidential data may access the data upon request, involving the documentation of data access.

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Data availability statement

Data are available upon reasonable request. All patients who participated in this study gave written informed consent. However, this consent did not include a provision stating that individual raw data can be made freely accessible to the public. Therefore, in accordance with the German data protection act §4 the underlying raw data cannot be made accessible to the public. Researchers meeting the criteria for access to confidential data may access the data upon request, involving the documentation of data access.

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Footnotes

  • JH and JM contributed equally.

  • Contributors JH: data acquisition and analysis, drafting and writing of the manuscript. JM: data analysis, drafting and writing of the manuscript. EMK: data acquisition drafting and writing of the manuscript. AM: drafting of the study, data analysis, drafting and writing of the manuscript.

  • Funding This work was supported by the German Research Foundation, SFB936/A5 to A.M.

  • Competing interests JH has received honoraria for consulting and/or serving on advisory boards as well as for speaking from Allergan, Autonomic Technologies Inc. (ATI), Cannovex BV, Chordate Medical AB, Eli Lilly, Hormosan Pharma, Lundbeck, Novartis, Sanofi and Teva. He received research support from Bristol Myers Squibb. He received personal fees for Medico-Legal Work as well as from Oxford University Press, Quintessence Publishing, Sage Publishing and Springer Healthcare. All these activities are unrelated to the submitted work.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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