RESUMO
Intracranial arteriovenous malformations (AVMs) are congenital anomalies where arteries and veins connect without a capillary bed. AVMs are the leading cause of nontraumatic intracerebral hemorrhages in people younger than 35 years old.1 The leptomeninges (arachnoid and pia) form from the meninx primitiva.2,3 Endothelial channels produce a vascular plexus in the meninx connected by primitive arachnoid. Remodeling of the plexus in response to changing metabolic demands results in a recognizable pattern of arteries and veins.2,3 Defects at the level of capillaries during arteriovenous specification are most likely responsible for arteriovenous fistula formation.4-6 Interplay between the congenital dysfunction and flow-related maturation in adulthood, when vasculogenesis has stopped, produces the AVM.6,7 The relationship between the primitive arachnoid and aberrant AVM vessels is preserved and forms the basis of microsurgical disconnection discussed in Video 1. Several authors have described dissecting these natural planes to delineate the abnormal AVM vessels, relax the brain, and avoid morbidity during AVM surgery.8-10 We recommend sharp arachnoid dissection with a scalpel or microscissors, occasionally helped by blunt dissection with patties or bipolar forceps. We present a 2-dimensional video of the microsurgical resection of a right parietal AVM. The patient, a healthy 30-year-old female, presented with intermittent headaches and mild impairment of arithmetic and visuospatial ability. Magnetic resonance imaging and digital subtraction angiography showed a compact 3.5-cm supramarginal gyrus AVM supplied by the middle cerebral artery, with superficial drainage. Complete microsurgical resection was performed without morbidity. We demonstrate the principles of arachnoid dissection requisite to disentanglement of the nidus and safe resection of the AVM.
Assuntos
Malformações Arteriovenosas Intracranianas , Microcirurgia , Feminino , Humanos , Adulto , Microcirurgia/métodos , Malformações Arteriovenosas Intracranianas/complicações , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Malformações Arteriovenosas Intracranianas/cirurgia , Artéria Cerebral Média/cirurgia , Aracnoide-Máter/diagnóstico por imagem , Aracnoide-Máter/cirurgiaRESUMO
Arachnoid granulations are hypertrophied arachnoid villi, which extend from the subarachnoid space into the venous system and aid in the passive filtration and reabsorption of cerebrospinal fluid. These macroscopic structures have been described in various locations, with the transverse and sigmoid sinuses seen as normal variants on imaging. Here we present the occurrence of an enlarged arachnoid granulation at the foramen rotundum where a variant intracranial venous sinus was identified during routine dissection. Variations, such as the one described herein, should be recognised by those who operate or interpret images of the skull base.
Assuntos
Aracnoide-Máter/anormalidades , Coristoma/patologia , Cavidades Cranianas/anormalidades , Tecido de Granulação/anormalidades , Idoso de 80 Anos ou mais , Aracnoide-Máter/cirurgia , Cadáver , Coristoma/cirurgia , Cavidades Cranianas/cirurgia , Dissecação , Feminino , Tecido de Granulação/cirurgia , HumanosRESUMO
OBJECTIVE: We used microscopy to conduct qualitative and quantitative analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric, subtemporal (ST), and transchoroidal (TC). In addition, we performed a parahippocampal gyrus resection in the ST context. METHODS: Each approach was performed in 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the parahippocampal gyrus was resected through an ST approach. The qualitative analysis was based on anatomic observation and the quantitative analysis was based on the linear exposure of vascular structures and the area of exposure of the ambient cistern region. RESULTS: The ST approach provided good exposure of the inferior portion of the cistern and of the proximal segments of the posterior cerebral artery. After the resection of the parahippocampal gyrus, the area of exposure improved in all components, especially the superior area. A TC approach provided the best exposure of the superior area compared with the other approaches. The posterolateral approaches (SC/occipital interhemispheric) to the ambient cistern region provided similar exposure of anatomic structures. There was a significant difference (P < 0.05) in linear exposure of the posterior cerebral artery when comparing the ST/TC and ST/SC approaches. CONCLUSIONS: This study has demonstrated that surgical approaches expose dissimilarly the different regions of the ambient cistern and an approach should be selected based on the specific need of anatomic exposure.
Assuntos
Mesencéfalo/anatomia & histologia , Mesencéfalo/cirurgia , Microcirurgia/métodos , Procedimentos Neurocirúrgicos/métodos , Aracnoide-Máter/anatomia & histologia , Aracnoide-Máter/cirurgia , Cadáver , Veias Cerebrais/anatomia & histologia , Veias Cerebrais/cirurgia , Humanos , Giro Para-Hipocampal/anatomia & histologia , Giro Para-Hipocampal/cirurgia , Artéria Cerebral Posterior/anatomia & histologia , Artéria Cerebral Posterior/cirurgia , Espaço Subaracnóideo/cirurgiaRESUMO
The classical surgical technique for the resection of vestibular schwannomas (VS) has emphasized the microsurgical anatomy of cranial nerves. We believe that the focus on preservation of the arachnoid membrane may serve as a safe guide for tumor removal. Method The extracisternal approach is described in detail. We reviewed charts from 120 patients treated with this technique between 2006 and 2012. Surgical results were evaluated based on the extension of resection, tumor relapse, and facial nerve function. Results Overall gross total resection was achieved in 81% of the patients. The overall postoperative facial nerve function House-Brackmann grades I-II at one year was 93%. There was no recurrence in 4.2 years mean follow up. Conclusion The extracisternal technique differs from other surgical descriptions on the treatment of VS by not requiring the identification of the facial nerve, as long as we preserve the arachnoid envelope in the total circumference of the tumor.
Assuntos
Aracnoide-Máter/cirurgia , Nervo Facial , Microcirurgia/métodos , Neuroma Acústico/cirurgia , Procedimentos Neurocirúrgicos/métodos , Tratamentos com Preservação do Órgão/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Traumatismos do Nervo Facial/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroma Acústico/patologia , Complicações Pós-Operatórias , Período Pós-Operatório , Estudos Retrospectivos , Espaço Subaracnóideo/cirurgia , Resultado do Tratamento , Carga Tumoral , Adulto JovemRESUMO
The classical surgical technique for the resection of vestibular schwannomas (VS) has emphasized the microsurgical anatomy of cranial nerves. We believe that the focus on preservation of the arachnoid membrane may serve as a safe guide for tumor removal. Method The extracisternal approach is described in detail. We reviewed charts from 120 patients treated with this technique between 2006 and 2012. Surgical results were evaluated based on the extension of resection, tumor relapse, and facial nerve function. Results Overall gross total resection was achieved in 81% of the patients. The overall postoperative facial nerve function House-Brackmann grades I-II at one year was 93%. There was no recurrence in 4.2 years mean follow up. Conclusion The extracisternal technique differs from other surgical descriptions on the treatment of VS by not requiring the identification of the facial nerve, as long as we preserve the arachnoid envelope in the total circumference of the tumor. .
A técnica cirúrgica clássica para ressecção de schwannomas vestibulares enfatiza a anatomia microcirúrgica dos nervos cranianos. Acreditamos que o foco na preservação da membrana aracnóide pode servir como parâmetro seguro para a remoção do tumor. Método A abordagem extracisternal é descrita em detalhe. Analisamos o prontuário de 120 pacientes tratados com esta técnica entre 2006 e 2012. Os resultados cirúrgicos foram baseados em extensão de ressecção, recorrência tumoral e função do nervo facial. Resultados Ressecção total foi obtida em 81% dos pacientes. O resultado global da função do nervo facial (House-Brackmann graus I-II) após um ano da cirurgia foi de 93%. Não houve recidiva em um seguimento médio de 4,2 anos. Conclusão A técnica extracisternal difere de outras descrições cirúrgicas no tratamento de schwannoma vestibular pois não requer a identificação do nervo facial, contanto que o plano de aracnóide seja preservado em toda circunferência do tumor. .
Assuntos
Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Aracnoide-Máter/cirurgia , Nervo Facial , Microcirurgia/métodos , Neuroma Acústico/cirurgia , Procedimentos Neurocirúrgicos/métodos , Tratamentos com Preservação do Órgão/métodos , Traumatismos do Nervo Facial/prevenção & controle , Neuroma Acústico/patologia , Complicações Pós-Operatórias , Período Pós-Operatório , Estudos Retrospectivos , Espaço Subaracnóideo/cirurgia , Resultado do Tratamento , Carga TumoralRESUMO
BACKGROUND: To describe the neuroendoscopic treatment of interhemispheric arachnoid cysts. METHODS: Five children (aged 1-9 months) harboring interhemispheric arachnoid cysts underwent the procedure. The neuroendoscopic technique included cystoventriculostomy and cystocisternostomy. Imaging exams were compared before and after surgery, and the differences in cyst diameters were calculated. Head circumference and neurological development were also evaluated. RESULTS: The cystoventriculostomy was performed through the lateral ventricle in 4 cases and through the third ventricle in 4 cases. An added cystocisternostomy was performed in 1 case. Cyst diameters were reduced in the anterior-posterior, lateral-medial and superior-inferior planes in 22, 31 and 31% of the cases, respectively. The rate of increasing head circumference slowed; however, all the children continued to show slight macrocrania. There were complications in 2 cases: cerebrospinal fluid fistula was managed by lumbar puncture in 1 case and subdural collection was treated with a shunt in another single case. CONCLUSION: The neuroendoscopic approach to interhemispheric arachnoid cysts was effective with few complications.
Assuntos
Cistos Aracnóideos/cirurgia , Neuroendoscopia/métodos , Ventriculostomia/métodos , Aracnoide-Máter/cirurgia , Cistos Aracnóideos/patologia , Feminino , Humanos , Lactente , Recém-Nascido , Ventrículos Laterais/cirurgia , Imageamento por Ressonância Magnética , Masculino , Estudos Retrospectivos , Terceiro Ventrículo/cirurgia , Resultado do TratamentoAssuntos
Artéria Cerebral Anterior/cirurgia , Craniotomia/métodos , Dissecação/métodos , Aneurisma Intracraniano/cirurgia , Procedimentos Neurocirúrgicos/métodos , Hemorragia Subaracnóidea/cirurgia , Artéria Cerebral Anterior/anatomia & histologia , Artéria Cerebral Anterior/patologia , Aracnoide-Máter/anatomia & histologia , Aracnoide-Máter/cirurgia , Humanos , Aneurisma Intracraniano/patologia , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/prevenção & controle , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Crânio/anatomia & histologia , Crânio/cirurgia , Osso Esfenoide/anatomia & histologia , Osso Esfenoide/cirurgia , Hemorragia Subaracnóidea/patologiaRESUMO
BACKGROUND: The arachnoid knife is a useful instrument when performing a variety of neurosurgical procedures, for example, while opening the sylvian fissure or basal arachnoid bridges in the pterional approach or during the peripheral delimitation and excision of a cortical AVM. At present, there exists a wide variety of arachnoid knives made from different materials (stainless steel, titanium, or diamond-tipped); however, most of these instruments are expensive and may become dull with continuous use or bad handling. METHODS: In this article, we report the use and advantages of an arachnoid knife from a simple hypodermic needle. RESULTS: In the last 6 years, we have used this technique to open the arachnoid layer in more than 350 neurosurgical procedures. Furthermore, it can be used to perform sharp arteriotomies during bypass procedures or to open the dura mater over bone structures. To date, no complication arising from this simple technique has been documented. CONCLUSIONS: A standard hypodermic needle can be used in the operating room as a practical arachnoid knife. It has the characteristics of being effective, low-cost, and available worldwide.
Assuntos
Aracnoide-Máter/cirurgia , Revascularização Cerebral/instrumentação , Agulhas , Procedimentos Neurocirúrgicos/instrumentação , Revascularização Cerebral/métodos , Humanos , Procedimentos Neurocirúrgicos/métodosRESUMO
Thoracic spine arachnoid ossification is a relatively rare disease that affects mainly women and causes sensory, motor, and sphinctal symptoms associated with inferior limb pain. Based on three cases, the authors comment on pathogenic and surgery-related aspects of the disease. The patient in Case 1 was followed over the course of 23 years. Spinal cavitation is highlighted in Case 2, and yellow, gross, half-ring ossification is described in Case 3. Calcium deposits usually occur in the middle and lower thoracic spine where the majority of trabeculated arachnoid cells are located. Operative treatment does not interrupt the ossification process, which continues over time, causing progressive deterioration in the patient. Spinal cavitation can occur due to spinal cord tethering, stretching, and central cord edema formation, accompanied by cerebrospinal fluid blockage and pulse pressure changes. The results of surgical intervention are poor, offering short-term recovery with later deterioration. Multiple pathogenic factors are involved in this clinical syndrome including metabolic changes.
Assuntos
Aracnoide-Máter , Doenças do Sistema Nervoso Central/complicações , Ossificação Heterotópica/complicações , Doenças da Medula Espinal/etiologia , Vértebras Torácicas , Adulto , Aracnoide-Máter/patologia , Aracnoide-Máter/cirurgia , Doenças do Sistema Nervoso Central/diagnóstico , Doenças do Sistema Nervoso Central/cirurgia , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Pessoa de Meia-Idade , Ossificação Heterotópica/diagnóstico , Ossificação Heterotópica/cirurgia , Reoperação , Doenças da Medula Espinal/diagnóstico , Doenças da Medula Espinal/cirurgia , Vértebras Torácicas/patologia , Vértebras Torácicas/cirurgiaRESUMO
Con el propósito de estudiar la sensibilidad de los potenciales evocados visuales (PEV) a maniobras quirúrgicas de interés, así como la influencia de algunas variables potencialmente confusas se monitorearon dichos PEV durante pasos críticos de la cirugía hipofisiaria transfenoidal a 57 pacientes con tumores y aracnoidoceles operados en el Hospital Clínicoquirúrgico "Hermanos Ameijeiras" durante 18 meses. Se encontró incremento de amplitud durante la resección tumoral y disminución relativa durante el taponamiento. El único posible factor que pudo haber ejercido influencia sobre las variables monitoreadas fue la inyección de nuevas dosis de anestésico durante la operación. Se concluyó que la amplitud del componente positivo principal fue el indicador mas sensible de manipulación quirúrgica para el monitoreo del posible efecto lesivo de ésta sobre el quiasma óptimo