Greater occipital nerve block modulates nociceptive signals within the trigeminocervical complex

TY - JOUR

T1 - Greater occipital nerve block modulates nociceptive signals within the trigeminocervical complex

AU - Hoffmann, Jan

AU - Mehnert, Jan

AU - Koo, Elena M

AU - May, Arne

N1 - © Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.

PY - 2021/12

Y1 - 2021/12

N2 - 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.

AB - 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.

U2 - 10.1136/jnnp-2021-326433

DO - 10.1136/jnnp-2021-326433

M3 - SCORING: Journal article

C2 - 34312221

VL - 92

SP - 1335

EP - 1340

JO - J NEUROL NEUROSUR PS

JF - J NEUROL NEUROSUR PS

SN - 0022-3050

IS - 12

ER -