CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / IntroduÃÃo: Hà vÃrias evidÃncias na literatura que validaram o conceito de compressÃo neurovascular (CNV) como causa principal da neuralgia trigeminal (NT) primÃria, justificando a descompressÃo vascular microcirÃrgica (DVMC) como a principal opÃÃo terapÃutica. Paralelamente, outros estudos demonstraram que o resultado em longo prazo da DVMC depende do grau de intensidade da CNV. No tocante à fisiopatologia da NT, trabalhos recentes mostraram que a CNV pode ocasionar alteraÃÃes morfolÃgicas do nervo trigÃmeo (nTRI), tais como deformaÃÃo, desmielinizaÃÃo focal e atrofia neural. Contudo, pouca informaÃÃo à conhecida sobre a real natureza da lesÃo existente nos nTRI de pacientes com NT. Objetivo: O objetivo deste trabalho foi estudar as caracterÃsticas por ressonÃncia magnÃtica (RM) de alta resoluÃÃo das CNV e as alteraÃÃes estruturais dos nTRI em pacientes com NT primÃria. MÃtodo: Nos protocolos I (RM de 1,5 Tesla [T]) e II (RM de 3,0 T), foram estudados, respectivamente, 100 e 40 pacientes, submetidos à DVMC para tratamento de NT. Todos os pacientes foram submetidos, no prÃ-operatÃrio, Ãs trÃs sequÃncias seguintes em alta resoluÃÃo: 3D T2, 3D time-of-flight (TOF) magnetic resonance angiography (MRA) e 3D T1 com injeÃÃo de GadolÃnio (T1-Gd). As imagens foram analisadas e comparadas aos achados cirÃrgicos, quanto à identificaÃÃo e caracterizaÃÃo das CNV. No protocolo III, os parÃmetros anatÃmicos, volume (V) e Ãrea seccional (AS), dos nTRI de 50 pacientes com NT e de 20 indivÃduos normais (grupo controle), foram comparados entre os nTRI afetados (grupoipsilateralNT) e nÃo-afetados (grupo contralateralNT) dos pacientes e os nTRI controles. Osresultados foram correlacionados com as caracterÃsticas dos pacientes, as caracterÃsticas dasCNV e o resultado clÃnico dois anos apÃs a DVMC. No protocolo IV, a fraÃÃo de anisotropia(FA) e o coeficiente de difusÃo aparente (CDA) de 10 pacientes com NT e de seis indivÃduos normais (controle) foram obtidos em sequÃncia diffusion tensor imaging (DTI) em aparelhode 3,0 T e comparados entre os grupos ipsilateralNT, contralateralNT e controles. Resultados: No Protocolo I, a sensibilidade e a especificidade das imagens em detectar as CNV foram, respectivamente, 96,7% (88/91) e 100% (9/9). A anÃlise das imagens identificou corretamente o vaso responsÃvel pela compressÃo em 87,9% dos casos e o grau de intensidade da compressÃo em 84,6% casos. Jà no Protocolo II, a sensibilidade e a especificidade das imagens foram, respectivamente, 97,4% (37/38) e 100% (2/2). A anÃlise das imagensidentificou corretamente o vaso responsÃvel pela compressÃo em 89,1% dos casos e o grau deintensidade da compressÃo em 83,8% dos casos. No Protocolo III, as mÃdias de V e AS dogrupo ipsilateralNT foram menores (p<0,05) do que nos grupos contralateral NT e controle. No grupo ipsilateralNT, os menores valores de V e AS foram encontrados nos nTRI, cujas CNV eram de grau III, e naqueles, cujos pacientes foram considerados curados ao final do seguimento clÃnico (p<0,05). No Protocolo IV, a FA do grupo ipsilateralNT foi menor (p<0,05) do que nos grupos contralateralNT e controle. Jà o CDA do grupo ipsilateralNT foi maior (p<0,05) do que nos grupos contralateralNT e controle. ConclusÃo: As sequÃncias 3D T2, 3D TOF-MRA e 3D T1-Gd tiveram alta sensibilidade e alta especificidade na detecÃÃo de CNV e na prediÃÃo do grau de intensidade da compressÃo. Os resultados sugerem a existÃncia de importante atrofia nos nTRI afetados pelas CNV, estando a atrofia correlacionada ao grau / Introduction: Neurovascular compression (NVC) is commonly accepted as being, in most patients, the main or most common cause of primary trigeminal neuralgia (TN), justifying microvascular decompression (MVD) as first neurosurgical option. In the same idea, other studies demonstrated that the degree of severity of NVC correlated with the long-term sucess rate after MVD. The chronic NVC may originate morphological changes in the trigeminal nerve (TGN), like nerve deviation, focal demyelination and atrophy. By contrast, little
information is available about the real nature of the underlying nerve lesions of patients with TN. Objetive: The aim of this thesis was to study the characteristics by high-resolutionimaging (MRI) of NVC and structural alterations of TGN in patients with primary TN. Methods: On the First (MRI 1.5 Tesla [T]) and Second (MRI 3.0 T) Protocols, we studied, respectively, 100 and 40 patients, who underwent MVD for TN. All patients underwent a MRI with 3D T2-weighted, 3D time-of-flight (TOF) magnetic resonance angiography(MRA), and 3D T1-weighted Gadolinium-enhanced sequences in combination. Imaging analysis were performed to detect and to assess features of NVC and these data compared with the operative findings. On the Third Protocol, anatomical TGN parameters (volume, V; and cross-sectional Ãrea, CSA), obtained in 50 patients with primary TN and in 20 normal control subjects (control group), were compared between the symptomatic (ipsilateralTN group) and asymptomatic (contralateralTN group) sides of the face of patients and both sides
of the control group. These data were correlated with patientâs characteristics, NVC characteristics and clinical outcomes at the 2-year follow-up after surgery. On the Fourth Protocol, the fraction of anisotropy (FA) and the apparent diffusion coefficient (ADC) ofTGN, in 10 patients with primary TN and in 6 normal control subjects, were obtained in a diffusion tensor imaging (DTI) sequencing, in a 3,0 T MRI, and compared between the ipsilateralTN, contralateralTN and control groups. Results: On the First Protocol, MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9) for NVC detection. Image analysis correctly identified compressible vessel in 87.9% of cases and degree of compression in 84,6% of cases. On the Second Protocol, MRI sensitivity was 97.4% (37/38) and specificity 100% (2/2) for NVC detection. Image analysis correctly identified compressible vessel in 89.1% of cases and degree of compression in 83.8% of cases. On the Third Protocol, the mean V and CSA of the TGN on the ipsilateralTN group was significantly smaller (p<0.05) than those for the contralateralTN and control groups. On the ipsilateralTN group, the lowest values of V and CSA were found in TGN with NVC of grade III and in those of patients considered cured at 2-year of follow-up (p<0.05). On the Fourth Protocol, the FA of the ipsilateralTN group was significantly smaller (p<0.05) than those for the contralateralTN and control groups. The ADC of ipsilateralTN group was significantly higher (p<0.05) than those for the contralateralTN and control groups. Conclusion: 1.5 T or 3.0 T MRI using 3D T2- weighted in combination with 3D TOF-MRA and 3D T1-weighted Gadolinium-enhanced sequences proved to be reliable in detecting NVC and in predicting the degree of root compression. Results showed that atrophic changes, found in TGN of affected side of patients, were correlated with the severity of compression and clinical outcomes. Our work demonstrated also that DTI revealed alteration in FA and ADC values of affected TGN, and these alterations were correlated with atrophic changes in patients with TN caused by NVC.
| Identifer | oai:union.ndltd.org:IBICT/oai:www.teses.ufc.br:9826 |
| Date | 30 January 2015 |
| Creators | Paulo Roberto Lacerda Leal |
| Contributors | Miguel Ãngelo Nobre e Souza, Gerardo Cristino Filho, JosenÃlia Maria Alves Gomes, Josà Daniel Vieira de Castro, PAULO NIEMEYER SOARES FILHO, MARC SINDOU |
| Publisher | Universidade Federal do CearÃ, Programa de PÃs-GraduaÃÃo em Cirurgia, UFC, BR |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFC, instname:Universidade Federal do Ceará, instacron:UFC |
| Rights | info:eu-repo/semantics/openAccess |
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