Bloqueio anestesico do nervo occipital maior na profilaxia da migranea

Abstract

Resumo: A migranea envolve em sua fisiopatologia um grande numero de estruturas encefalicas, sendo o nervo trigemeo (NT) uma das principais. Com o objetivo de determinar uma possivel influencia do nervo occipital maior (NOM) sobre o comportamento da migranea, foram estudados 37 pacientes com esta patologia. Utilizando-se de um estudo duplo cego "cross-over", submeteram-se os pacientes a infiltracao do NOM com bupivacaina 0,5% (BP) e soro fisiologico 0,9% (SF). Os efeitos clinicos foram avaliados: subjetivamente, pela escala visual analogica da dor, determinando-se o numero, duracao e intensidade das crises; objetivamente, pela determinacao dos limiares de percepcao dolorosa (algometria) sobre o NOM e ramos do NT. As avaliacoes ocorreram antes da primeira, apos a primeira e apos a segunda infiltracao. Os resultados algometricos nao apresentaram diferencas estatisticamente significativas entre o grupo que iniciou o estudo com SF e apos passou a utilizar BP (SF-BP) e o grupo que iniciou com BP e apos passou a utilizar SF (BP-SF). No grupo (BP-SF): o numero de crises, a duracao e a intensidade nao se alteraram apos a primeira infiltracao; apos a segunda infiltracao o numero das crises nao se alterou, porem a duracao e a intensidade reduziram-se (p=0,029) e (p=0,035). No grupo (SF-BP): o numero, a duracao e a intensidade das crises nao se alteraram apos a primeira infiltracao; apos a segunda infiltracao o numero e a intensidade das crises nao se alteraram, porem a duracao das crises reduziu-se (p=0,015). A comparacao entre os grupos (BP-SF) e (SF-BP) mostrou que: o numero de crises e a duracao nos periodos antes e apos a primeira infiltracao e apos a segunda infiltracao nao apresentaram diferencas estatisticamente significativas; a intensidade das crises foi menor no grupo (BP-SF) somente apos a Segunda infiltracao (p=0,020), nos demais momentos nao se observaram diferencas entre os grupos. Concluiu-se que o bloqueio anestesico com BP sobre o NOM nao altera o numero e a duracao das crises, porem promove uma reducao em sua intensidade apos 60 dias da infiltracao. Os resultados aqui apresentados sugerem que o NOM participa na modulacao nociceptiva craniana durante as crises de migranea sem aura.

Abstract: Migraine comprises a great many encephalic structures in its physio-pathology, with the trigeminal nerve (TN) type being one of the main ones. For the purpose of determining a possible influence of the greater occipital nerve on migraine behavior, 37 patients who showed this pathology were studied. Using a double blind "cross over" group and submitting those patients to a GON infiltration with bupivacaina 0,5% (BP) and physiological serum 0,9%(PS), the clinical effects were evaluated: subjectively, through a pain analytical visual scale, determining the number of crises as well as their duration and intensity; objectively, by determining the threshold of pain perception (algometry) on the GON and TN branches. The evaluation was conducted before the first infiltration, after the first one and after the second one. The algometrical results didn't shown significant statistical differences between the group which initiated the study with PS and then started using (BP) (PS-BP) and the group which initiated with BP and then started using PS (BP-PS). In the (BP - PS) group the number, duration and intensity of the crises didn't change after the first infiltration; after the second one, the number of the crises didn't change, but their duration and intensity diminished (p=0,029) and (p=0,035). In the (PS - BP) group the number, duration and intensity of the crises didn't change after the first infiltration; after the second one, the number of the crises and their intensity didn't change, but the duration decreased (p= 0,015). The comparison between the two groups (BP-PS) and (PS-BP) has shown that: the number didn't and duration of the crises before and after the first infiltration and after the second one didn't show significant statistical differences; the intensity of the crises was lower in group (BP-PS) only after the second infiltration (p=0,020), in the other moments no differences have been observed between the groups. The conclusion is that the anesthetic blockage with BP on the GON doesn't change the number of crises and their duration, but it does provokes an intensity reduction after 60 days from the infiltration. The results shown here suggest that GON participates in the cranial nociceptive modulation during crises of migraine without aura.