Superficial-Temporal-Artery-To-Middle-Cerebral-Artery Bypass in Cerebrovascular Occlusive Disease and Hemodynamic-Related Ischemia: Illustrative Case and Literature Review

Stroke is the third most common cause of death worldwide. About 10% to 15% of strokes related to the territory of the carotid artery are associated with its complete occlusion. There is an important subgroup of patients with cerebrovascular occlusive diseases who might benefit from an external-carotid-to-internal-carotid bypass. In the present study, we report a case of a 53-year-old male patient with stenosis of the M2 branch of themiddle cerebral artery (MCA), with a history of 20 episodes of transient ischemic accidents (TIA)s, in whom an anastomosis of the M4 branch of the superficial temporal artery-MCA was performed. The patient was discharged in three days, and in the two years of follow-up, they were no more TIAs.We also conducted a review of the literature on cerebrovascular occlusive disease and extracranial-intracranial bypass surgery. New methods to evaluate cerebral hemodynamics made it possible to classify a new subgroup of patients with symptomatic cerebrovascular disease and documented cerebrovascular compromise in whom the drug therapy fails, who can benefit from the extracranial-intracranial bypass. Our case report illustrates the advantages of revascularization in these selected patients.

Intracranial aneurysm and arachnoid cyst: just a coincidence? A case report

ABSTRACT CONTEXT: Presence of an arachnoid cyst and a non-ruptured intracystic brain aneurysm is extremely rare. The aim of this paper was to describe a case of a patient with an arachnoid cyst and a non-ruptured aneurysm inside it. Clinical, surgical and radiological data were analyzed and the literature was reviewed. CASE REPORT: A patient complained of chronic headache. She was diagnosed as having a temporal arachnoid cyst and a non-ruptured middle cerebral artery aneurysm inside it. Surgery was performed to clip the aneurysm and fenestrate the cyst. CONCLUSIONS: This report raises awareness about the importance of intracranial vascular investigation in patients with arachnoid cysts and brain hemorrhage.

Middle cerebral artery aneurysms: aneurysm angiographic morphology and its relation to pre-operative and intra-operative rupture / Aneurismas da artéria cerebral média: morfologia angiográfica dos aneurismas e sua relação com ruptura pré-operatória e intra-operatória

ABSTRACT Objective Correlate the middle cerebral artery bifurcation aneurysm morphology with the pre-operative and intra-operative risk of rupture. Methods Forty patients with 46 middle cerebral artery bifurcation aneurysms were treated microsurgically by the same surgeon. Aneurysms were classified according to shape and the Fisher test was applied to analyze the effect of morphology on the pre-operative and intra-operative rupture. Results Pre-operative and intra-operative ruptures were observed in 8/46 patients (17.4%) and 14/46 patients (30.4%) respectively. Thirty-two cases (69.6%) had no symptoms postoperatively, modified Rankin score (MRS) of 0; 6.5% had MRS of 1 (no significant disability); 13% had MRS of 2 (slight disability); 4.3% had moderately severe disability (MRS of 4); and there were 3 deaths (6.5%) post-operatively. The morphology was not directly related to the rupture rate. Conclusion In general, ruptures are not affected by the morphology or the studied variables. Larger series are needed to validate these outcomes.

RESUMO Objetivo Correlacionar a morfologia do aneurisma da bifurcação da artéria cerebral média com o risco de ruptura pré-operatória e intra-operatória. Métodos 40 pacientes com 46 aneurismas de bifurcação da artéria cerebral média receberam tratamento microcirúrgico pelo mesmo cirurgião. Os aneurismas foram classificados de acordo com a morfologia e o teste de Fisher foi aplicado para analisar o efeito da morfologia sobre a ruptura pré-operatória e intra-operatória. Resultados As rupturas pré e intra-operatória foram observadas em 8/46 pacientes (17,4%) e 14/46 (30,4%) respectivamente. Trinta e dois casos (69,6%) não apresentaram sintomas pós-operatórios, pontuação de Rankin modificada (MRS) de 0, 6,5% tinham MRS de 1 (sem incapacidade significativa), 13% tinham MRS de 2 (leve incapacidade), 4,3% moderadamente grave (MRS de 4) e houve 3 óbitos (6,5%) durante o pós-operatório. A morfologia não estava diretamente relacionada à taxa de ruptura pré-operatória ou intra-operatória. Conclusão Em geral, as rupturas não são afetadas pela morfologia ou pelas variáveis estudadas. São necessárias séries maiores para validar esses resultados.

Use of Three-Dimensional Curved-Multiplanar Reconstruction Images for Sylvian Dissection in Microsurgery of Middle Cerebral Artery Aneurysms

PURPOSE: The purpose of this study was to introduce a method of using three-dimensional (3D) curved-multiplanar reconstruction (MPR) images for sylvian dissection during microsurgical treatment of middle cerebral artery (MCA) aneurysms. MATERIALS AND METHODS: Forty-nine patients who had undergone surgery for MCA aneurysms were enrolled. We obtained the 3D curved-MPR images along the sphenoid ridge using OsiriX MD™ imaging software, compared sylvian dissection time according to several 3D MPR image factors, and investigated the correlations between these images and intraoperative findings. RESULTS: Utilizing preoperative information of the sylvian fissure (SF) and peri-aneurysmal space on 3D curved-MPR images, we could predict the feasibility of sylvian dissection for a safe surgery. 3D curved-MPR images showed several features: first, perpendicular images to the sylvian surface in the same orientation as the surgeon's view; second, simultaneous visualization of the brain cortex, vessels, and cisternal space; and third, more accurate measurement of various parameters, such as depth of the MCA from the sylvian surface and the location and width of the SFs. CONCLUSION: In addition to conventional image studies, 3D curved-MPR images seem to provide useful information for Sylvian dissection in the microsurgical treatment of MCA aneurysms.

Transient middle cerebral artery occlusion in rats as an experimental model of brain ischemia / Modelo experimental de isquemia cerebral em ratos por obliteração temporária da artéria cerebral média

PURPOSE: To assess a rat model of cerebral ischemia induced by occlusion of the middle cerebral artery and its effect on the area of cerebral infarction. METHODS: Brain ischemia was induced in 52 male Wistar rats by introduction of a 3-0 nylon suture into the middle cerebral artery for either 90 (n=28) or 120 (n=24) minutes. Ischemic injury volume was determined by TTC staining, digital photography and analysis with the Image J software. Statistical analysis employed Student’s t test and the Mann-Whitney U test. RESULTS: The groups were similar in terms of weight (p=0.59). The length of thread inserted was 14.7 mm in the 90 min group and 20.2 mm in the 120 min group (p=0.37). Ischemic injury was detected in 11 animals (39 percent) after 90 min and 11 (45 percent) after 120 min (p=0.77). In animals exhibiting injury, filament length was 16.1±11 mm (90 min) vs. 21.9±7.4 mm (120 min) (p=0.15). The mean infarction zone volume was greater after 120 (259.2 mm³) than after 90 min (162.9 mm³) (p=0.04). The neurological deficit score for the 90 and 120 min groups was 2.0 and 2.4, respectively (p=0.84). CONCLUSION: The experimental model induced significant ischemic cerebral injury in both groups.

OBJETIVO: Avaliar o modelo de isquemia cerebral por oclusão da artéria cerebral média, mediante introdução de fio intraluminal por 90 e 120 minutos, e seu efeito sobre a área de infarto cerebral em ratos. MÉTODOS: 52 ratos machos Wistar foram submetidos à isquemia cerebral por introdução de fio de nylon 3-0 na artéria cerebral média por 90 ou 120 minutos. O volume da lesão isquêmica foi determinado pelo corante TTC, fotografia digital e utilização do programa ImageJ. Na análise estatística, foi utilizado o teste t- student e o U de Mann-Whitney. RESULTADOS: O comprimento do fio introduzido foi de 14,7 mm no grupo 90 minutos e 20,2 mm no grupo 120 minutos. Lesão isquêmica foi detectada em 11 animais (39 por cento) no grupo que de 90 minutos e 11 (45 por cento) do grupo de 120 minutos. Nos animais que apresentaram lesão, o comprimento do fio foi de 16,1±11 mm (90 minutos) e 21,9±7,4 mm (120 minutos). O volume médio da área de infarto foi maior no grupo 120 minutos do que no grupo 90 minutos. O escore de déficit neurológico foi de 2,0 no grupo 90 minutos e de 2,4 no grupo 120 minutos. CONCLUSÃO: O modelo experimental estudado induz lesão isquêmica cerebral significativa em ambos os grupos.

Middle cerebral artery aneurysms: challenges for microsurgical approach

The authors present their series about middle cerebral artery (MCA) aneurysms. They discuss anatomical aspects as well as the results and complications of surgical treatment. Besides, they defend the idea that for having good results, it is necessary an extent Sylvian´s cistern dissection, permitting an adequate exposure of the aneurysms and their relationships not only with the MCA but with its branches, emphasizing too the not usefulness of temporary clipping in the approach of this pathology.

Assessment of Cerebrovascular Reserve before and after STA-MCA Bypass Surgery by SPECT and SPM Analysis

OBJECTIVE: The purpose of this study was to objectively assess the efficacy of superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery using Technetium (Tc)-99m-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients who underwent STA-MCA bypass surgery. MATERIALS AND METHODS: Brain perfusion SPECT images obtained at baseline and after the administration of acetazolamide were reconstructed using statistical parametric mapping in 23 patients, both before and after STA-MCA bypass surgery. The clinical outcomes of the surgery were also recorded and compared with the hemodynamic changes. A voxel with an uncorrected p-value of less than 0.001 was considered to be statistically significant. RESULTS: SPECT images of the territory supplied by the bypass graft showed an increase in both cerebrovascular flow and reserve at baseline, and the increase was significantly higher following the administration of acetazolamide. All patients showed improvement of clinical symptoms and increased blood flow to the left temporal, parietal, and frontal cortices as well as the thalamus. CONCLUSION: Brain SPECT effectively and objectively demonstrated the improved outcomes of STA-MCA bypass surgery, and thus may be used in postoperative analyses.

Microanatomía de los segmentos M1 y M2 de la arteria cerebral media en hemisferios humanos de origen chileno: correlación con la literatura internacional / Median cerebral artery segments M1 and M2 microanatomy in chilean human hemispheres: correlation with international literature

La arteria cerebral media (ACM) es el más largo y complejo de todos los vasos intracerebrales, irrigando la mayor parte de los lóbulos frontales, parietales y temporales de ambos hemisferios cerebrales. Además de suplir el riego sanguíneo de una gran parte del cerebro, la ACM y sus ramas, están frecuentemente involucradas en enfermedades intracerebrales como hemorragias cerebrales, patología ateroesclerótica o degenerativa de la pared arterial, embolias y procesos inflamatorios. La alta frecuencia de patología y el amplio volumen cerebral irrigado por esta arteria hacen que el conocimiento de su anatomía sea fundamental en la descripción de los posibles mecanismos fisiopatológicos de las enfermedades que la involucran, así como para su estudio imagenológico y abordaje quirúrgico. El objetivo de este trabajo es comparar la anatomía macroscópica y microscópica de la ACM de sujetos chilenos con la publicada en series internacionales. Se estudiaron 10 hemisférios cadavéricos provenientes de 5 pacientes adultos de nacionalidad chilena cuya muerte no fue de causa encefálica, fijados con solución de formalina sometiendo a tinción los vasos arteriales. Se realizaron mediciones de la ACM y sus segmentos M1 y M2 comparando mediante análisis estadístico los resultados obtenidos con los publicados en la literatura. El análisis de éstos sugiere que las características anatómicas de la ACM de hemisferios provenientes de sujetos de nacionalidad chilena son similares a los reportados por estudios realizados con hemisferios cerebrales de sujetos de origen anglo-sajón.

Tratamento cirúrgico dos aneurismas não rotos da artéria cerebral média / Surgical treatment of unruptured middle cerebral artery aneurysms

Descrevemos nossa experiência no tratamento microcirúrgico de 34 pacientes portadores de aneurismas não rotos da artéria cerebral média. Houve prevalência no sexo masculino. Oitenta e três por cento dos aneurismas apresentava tamanho menor que 10 mm. Não houve óbito na presente série, com morbidade de 3 por cento após 1 ano. Indicamos, portanto, microcirurgia como tratamento de escolha para os aneurismas não rotos da artéria cerebral média.

Anastomose arterial extra-intracraniana para tratamento de paciente com isquemia cerebral refratária ao manejo clínico / Extra-intracranial arterial bypass for treatment of patient with clinical refractory cerebral ischemia

A anastomose extra-intracraniana pode ser utilizada em casos selecionados de insuficiência vascular encefálica refratária ao tratamento clínico. Descrevemos um caso de isquemia encefálica em território de artéria cerebral média direita devida à oclusão da artéria carótida interna homolateral com conseqüente redução da perfusão e reserva vascular nos hemisférios frontal e parietal. Apesar do tratamento clínico, a melhora do déficit motor estava relacionada diretamente com a manutenção de níveis tensionais sistêmicos elevados pelo uso de vasopressor. Após anastomose extra-intracraniana término-lateral entre as artérias temporal superficial e cerebral média direita, houve melhora significativa da perfusão cerebral com remissão do déficit motor.

Saphenous vein graft bypass in the treatment of giant cavernous sinus aneurysms: report of two cases

Two cases of giant intracavernous aneurysms treated by high flow bypass with saphenous vein graft between the external carotid artery (ECA) and branches of the middle cerebral artery (MCA) are presented. Very often these aneurysms are unclippable because they are fusiform or have a large neck. Occlusion of the internal carotid artery (ICA) is the treatment of choice in many cases. This procedure has however a high risk of brain infarction. Revascularization of the brain by extra-intracranial anastomosis between the superficial temporal artery (STA) and branches of the MCA is frequently performed. This procedure provides however a low flow bypass and brain infarction may occur. We report two cases of giant cavernous sinus aneurysms treated by high flow bypass and endovascular balloon occlusion of the ICA. Immediate high flow revascularization of MCA branches was achieved and the patients showed no ischemic events. Follow-up of 8 and 14 months after operation shows patency of the venous graft and no neurological deficits. Angiographic control examination showed complete aneurysm occlusion in both cases.