Intracranial arachnoid cysts and epilepsy in children: Should this be treated surgically? Our 29-year experience and review of the literature / Quistes aracnoideos intracraneales y epilepsia en niños: ¿Debemos tratarlos quirúrgicamente? Nuestra experiencia de 29 años y revisión de la literatura

Introduction and objective: Arachnoid cysts (ACs) are relatively frequent lesions related to different neurological symptoms, being mostly incidentally diagnosed. This study aims to clarify whether AC surgery in epileptic patients is useful in their treatment. Material and methods: The patients registered in the database of the Neuropediatrics Section from May 1990 to August 2019 are analyzed retrospectively. Patients in whom the diagnosis of ACs and epilepsy coincide are studied. The location, size and number of ACs, neurological development, age at diagnosis, follow-up time, the performance of surgery on the cyst, evolution, anatomical relationship between brain electrical activity and location of AC, and type of epilepsy are analyzed. Results: After analyzing the database, we found 1881 patients diagnosed with epilepsy, of which 25 had at least one intracranial AC. In 9 of the patients, cerebral or genetic pathologies were the cause of epilepsy. Of the other 16, only 2 patients showed that the type of epilepsy and the epileptogenic focus coincided with the location of the AC; one of them was surgically treated without success, and the other one remained asymptomatic without receiving medical or surgical treatment(AU)

Introducción y objetivo: Los quistes aracnoideos (QAs) son lesiones relativamente comunes relacionados con diferentes síntomas neurológicos, siendo diagnosticados de forma incidental en su mayoría. Este estudio tiene como objetivo aclarar si la cirugía sobre el QA en pacientes epilépticos es útil en su tratamiento. Material y métodos: Se analizan retrospectivamente los pacientes registrados en la base de datos de la Sección de Neuropediatría desde mayo de 1990 a agosto de 2019. Se estudian los pacientes en los que coincide el diagnóstico de QA y epilepsia. Se analiza la localización, tamaño y número de los QA, el desarrollo neurológico, edad al diagnóstico, tiempo de seguimiento, realización de cirugía sobre el QA, evolución, relación anatómica entre la actividad eléctrica cerebral y la localización del QA, así como el tipo de epilepsia. Resultados: Tras el análisis de la base de datos encontramos 1.881 pacientes diagnosticados de epilepsia, entre ellos 25 con al menos un QA intracraneal. En nueve de los pacientes la patología cerebral o genética por sí misma era causa de epilepsia. De los otros 16, únicamente en dos casos se evidenció que el tipo de epilepsia y el foco epileptogénico coincidían con la localización del QA; uno de ellos fue tratado quirúrgicamente sin éxito y el otro permaneció asintomático sin recibir tratamiento médico ni quirúrgico. Conclusiones: Aunque es necesario diseñar un estudio prospectivo para establecer causalidad, los resultados de nuestro trabajo y la literatura disponible sugieren que no hay relación causal entre la presencia de QAs y epilepsia. El estudio y tratamiento de estos pacientes debería ser completado en una unidad multidisciplinar de cirugía de la epilepsia, sin asumir de inicio que el QA es la causa de la epilepsia(AU)

Intracranial arachnoid cysts and epilepsy in children: Should this be treated surgically? Our 29-year experience and review of the literature.

INTRODUCTION AND OBJECTIVE: Arachnoid cysts (ACs) are relatively frequent lesions related to different neurological symptoms, being mostly incidentally diagnosed. This study aims to clarify whether AC surgery in epileptic patients is useful in their treatment. MATERIAL AND METHODS: The patients registered in the database of the Neuropediatrics Section from May 1990 to August 2019 are analyzed retrospectively. Patients in whom the diagnosis of ACs and epilepsy coincide are studied. The location, size and number of ACs, neurological development, age at diagnosis, follow-up time, the performance of surgery on the cyst, evolution, anatomical relationship between brain electrical activity and location of AC, and type of epilepsy are analyzed. RESULTS: After analyzing the database, we found 1881 patients diagnosed with epilepsy, of which 25 had at least one intracranial AC. In 9 of the patients, cerebral or genetic pathologies were the cause of epilepsy. Of the other 16, only 2 patients showed that the type of epilepsy and the epileptogenic focus coincided with the location of the AC; one of them was surgically treated without success, and the other one remained asymptomatic without receiving medical or surgical treatment. CONCLUSIONS: Although it is necessary to design a prospective study to establish causality, the results of our research and the available literature suggest that there is no causal relationship between the presence of ACs and epilepsy. The study and treatment of these patients should be carried out in a multidisciplinary epilepsy surgery unit, without initially assuming that the AC is the cause of epilepsy.

Intracranial arachnoid cysts and epilepsy in children: Should this be treated surgically? Our 29-year experience and review of the literature.

INTRODUCTION AND OBJECTIVE: Arachnoid cysts (ACs) are relatively frequent lesions related to different neurological symptoms, being mostly incidentally diagnosed. This study aims to clarify whether AC surgery in epileptic patients is useful in their treatment. MATERIAL AND METHODS: The patients registered in the database of the Neuropediatrics Section from May 1990 to August 2019 are analyzed retrospectively. Patients in whom the diagnosis of ACs and epilepsy coincide are studied. The location, size and number of ACs, neurological development, age at diagnosis, follow-up time, the performance of surgery on the cyst, evolution, anatomical relationship between brain electrical activity and location of AC, and type of epilepsy are analyzed. RESULTS: After analyzing the database, we found 1881 patients diagnosed with epilepsy, of which 25 had at least one intracranial AC. In 9 of the patients, cerebral or genetic pathologies were the cause of epilepsy. Of the other 16, only 2 patients showed that the type of epilepsy and the epileptogenic focus coincided with the location of the AC; one of them was surgically treated without success, and the other one remained asymptomatic without receiving medical or surgical treatment. CONCLUSIONS: Although it is necessary to design a prospective study to establish causality, the results of our research and the available literature suggest that there is no causal relationship between the presence of ACs and epilepsy. The study and treatment of these patients should be carried out in a multidisciplinary epilepsy surgery unit, without initially assuming that the AC is the cause of epilepsy.

Quiste aracnoideo de la vaina del nervio óptico simulando defecto glaucomatoso en el campo visual / Optic nerve sheath arachnoid cyst simulating glaucomatous defect in the visual field

Resumen Introducción: el quiste aracnoideo es una colección benigna de fluido similar en composición al líquido cefalorraquídeo dentro de la aracnoides, circunscrita por tejido fibrovascular normal que comprime las leptomeninges que rodean el nervio óptico. Se describe el caso de una paciente con quiste aracnoideo de la vaina del nervio óptico con un defecto campimétrico típico de glaucoma, pero con un disco óptico sin características de glaucoma, con el fin de resaltar la necesidad de estudiar con neuroimágenes estos casos y detectar este tipo de alteraciones. El quiste aracnoideo de la vaina del nervio óptico es una entidad excepcional que generalmente tiene un comportamiento benigno, permaneciendo estable en el tiempo, aunque eventualmente puede producir una neuropatía óptica compresiva, afectando la agudeza o el campo visual por daño de la capa de fibras nerviosas. En el caso descrito, este daño se manifestó con un defecto de campo visual que simulaba neuropatía glaucomatosa.

Abstract Background: Arachnoid cyst is a benign fluid collection similar in composition to cerebrospinal fluid within the arachnoid, circumscribed by normal fibrovascular tissue that compresses the leptomeninges surrounding the optic nerve. Objective: To describe the case of a patient with an optic nerve sheath arachnoid cyst with a typical glaucoma campimetric defect, but with an optic disc without findings of glaucoma, to highlight the need to study these cases with neuroimaging to detect this type of changes. Conclusion: Optic nerve sheath arachnoid cyst is an exceptional entity that generally has a benign behavior remaining stable over time; but could eventually originate compressive optic neuropathy, affecting visual acuity or visual fields due to nerve fiber layer damage. In the patient´s case this damage was manifested with a visual field defect that simulated glaucomatous neuropathy.

Quiste aracnoideo intraventricular asintomático: reporte de un caso / Asymptomatic intraventricular arachnoid cyst: a case report

Introducción: Los Quistes Aracnoideos son colecciones benignas de líquido cefalorraquídeo que representan el 1% de lesiones ocupantes de espacios intracraneales. Se detecta frecuentemente antes de los 20 años, entre 60 a 90% de los casos. La prevalencia estimada es de 1,4% en adultos, siendo la menos frecuente la ubicación intraventricular. Caso Clínico: Mujer de 60 años de edad, consultó por cefalea holocraneana de larga data y ocasionales mareos. Sin alteraciones al examen físico neurológico. Se le realizó tomografía axial computarizada donde llamó la atención una leve alteración de la densidad intraventricular por lo que se procedió a realizar resonancia magnética nuclear que demostró imágenes quísticas en atrio de ventrículos laterales, bilateral. No se requirió de una intervención quirúrgica debido a que la paciente no presentaba sintomatología significativa. Discusión: El tratamiento quirúrgico es recomendado en pacientes sintomáticos, en quistes de gran extensión y en los que cursan con complicaciones. Para los pacientes que cursen sólo con dolor de cabeza, sin hidrocefalia secundaria o un aumento evidente de la presión intracraneal se recomienda la observación con o sin repetición de las imágenes.

Introduction: Arachnoid cysts are benign collections of cerebrospinal fluid that represents 1% of lesions occupying intracranial spaces. It is frequently detected before the age of 20, between 60 to 90% of cases. The estimated prevalence is 1.4% in adults, the least frequent being intraventricular location. Clinical Case: A 60-year-old woman attended for a long-standing holocranial headache and occasional dizziness. No alteration in the neurological physical examination. A computerized axial tomography was performed, where a slight alteration in the intraventricular density drew attention, for which a nuclear magnetic resonance was carried out, which showed cystic images in the atrium of bilateral lateral ventricles. No surgical intervention was required because the patient did not present a significant symptomatology. Discussion: Surgical treatment is recommended in symptomatic patients, in cysts of great extension and in those with complications. For patients with only headache, without secondary hydrocephalus or an obvious increase in intracranial pressure, observation with or without repetition of the images is recommended.

Neuroendoscopic treatment of arachnoid cysts in the paediatric population. Series results for 20 patients. / Tratamiento neuroendoscópico de quistes aracnoideos en edad pediátrica. Resultados de una serie de 20 pacientes.

INTRODUCTION: Neuroendoscopy has become an effective and safe treatment for arachnoid cysts in the paediatric population. We review the paediatric patients with arachnoid cysts treated by neuroendoscopy in our hospital and analyse the results. MATERIAL AND METHODS: A retrospective analysis of 20 patients operated on from 2005 to 2018. The variables assessed are: gender, age, clinical presentation, cyst site, presence of hydrocephalus and/or extra-axial collections, endoscopic procedures and complications. Procedure success is defined as an improvement in symptoms and reduction in cyst size until end of follow-up. RESULTS: Our series comprised 13 males and 7 females (mean age: 64.6 months, range: 4-172 months). The most frequent site was suprasellar-prepontine (7), followed by intraventricular (6), quadrigeminal (3), interhemispheric (2) and Sylvian (2). A total of 70% (14/20) of patients had hydrocephalus at diagnosis, which increased to 85% in suprasellar-prepontine cysts and 100% in quadrigeminal cysts. Only 4/14 patients with required a ventriculoperitoneal shunt (median age at diagnosis: 12.5 months). Of these 4 patients, 3 developed severe shunt overdrainage. The procedure was successful in 60% (12/20) of the patients in the series. Success by location was 57% (4/7) in suprasellar cysts, 33% (1/3) in quadrigeminal cysts, 66% (4/6) in intraventricular cysts, 100% (2/2) in interhemispheric cysts and 50% (1/2) in Sylvian cysts. Treatment thus failed in 8 cases, with a mean time to failure of 12.12 months (range: 0-45 months). A new neuroendoscopic procedure was performed in 4 of these 8 cases (success in 2/4), a ventriculoperitoneal shunt was placed in 2 cases, a cystoperitoneal shunt was placed in 1 case and the remaining case was managed conservatively. Mean follow-up time was 52.45 months (range: 3-129 months). CONCLUSIONS: Neuroendoscopy is an effective and safe treatment for arachnoid cysts in paediatric patients that also enables managing associated hydrocephalus in most cases. The choice of neuroendoscopic procedure and success rate depend on cyst location. Younger patients have been found to have a higher shunt dependency rate. In these cases, measures to prevent shunt overdrainage are recommended.

Quiste aracnoideo sacro recidivante con meningocele anterior gigante: reporte de caso / Sacral arachnoid recurrent cyst with giant anterior meningocele: a case report

Los quistes aracnoideos corresponden a lesiones benignas expansivas del canal medular secundarias a defectos anatómicos durales, mientras que los meningoceles anteriores consisten en la herniación de la duramadre hacia la pelvis a través de forámenes dilatados o defectos óseos. Ambas entidades son infrecuentes y sus manifestaciones clínicas puede variar de acuerdo a estructuras anatómicas que comprimen. Una historia clínica completa, la pesquisa diagnóstica y la adecuada interpretación de imágenes orientan al diagnóstico y manejo de estos pacientes. Se presenta el caso de una paciente adulta mayor con historia de masa pélvica, dolor lumbar severo y monoparesia en quien se realizó el diagnóstico incidental de quiste aracnoideo sacro y meningioma sacro anterior.

Arachnoid cysts are benign expansive lesions of the spinal canal secondary to dural defects, whereas the anterior meningoceles consist of the herniation of the dura into the pelvis through dilated foramina or bone defects. Both pathologies are infrequent and its clinical manifestations vary according to compressed anatomical structures. A complete clinical history, the diagnostic investigation and the correct imaging studies interpretation guide the diagnosis and management of these patients. We present the case of an elderly adult patient with a history of pelvic mass, severe lumbar pain and monoparesis in whom the incidental diagnosis of sacral arachnoid cyst and anterior sacral meningioma was performed.

Thoracolumbar epidural arachnoid cyst of difficult clinical management: case report / Cisto epidural aracnoídeo tóraco-lombar de difícil tratamento clínico: relato de caso / Quiste aracnoideo epidural toracolumbar de difícil tratamiento clínico: reporte de caso

ABSTRACT Introduction: Among the primary lesions occupying the spinal space, only 1% corresponds to the epidural arachnoid cyst (EAC). This condition is usually asymptomatic, and identified accidentally in imaging tests. In symptomatic cases, total surgical resection is recommended. Objective: To describe a case of EAC refractory to clinical treatment. Methods: A 45-year-old woman had lumbar pain for six years and increased pain in the last months, with irradiation to the left lower limb (corresponding to L1). No other alterations found in the physical examination. Magnetic resonance imaging (MRI) of the spine revealed an intravertebral cystic lesion at T12-L1 level, in the left posterolateral position, causing enlargement of the foramen, and suggesting an epidural arachnoid cyst. Results: Due to failure of the initial clinical treatment, the patient underwent left T12-L1 hemilaminectomy, resection of the cyst and correction of dural failure. The patient progressed with effective pain control and MRI confirmed absence of residual lesion. Conclusion: EAC is more common in men (4:1) and may be congenital or acquired. The most common topography is thoracic (65%). Its clinical presentation is low back pain, lower limb pain and paresthesia. MRI is the method of choice for diagnosis and surgical intervention is restricted to cases that are symptomatic or refractory to clinical treatment, and the prognosis tends to be excellent. We conclude that, in addition to being a rare and commonly asymptomatic condition, an adequate therapeutic approach is essential for complete cure, avoiding intense pain and manifestations that bring about a drastic reduction of functional capacity. Level of evidence: IV. Type of study: Case series.

RESUMO Introdução: dentre as lesões primárias que ocupam o espaço espinhal, apenas 1% corresponde ao cisto epidural aracnoideo (CEA). Esta patologia costuma ser assintomática, identificada acidentalmente em exames de imagem. Já em casos sintomáticos, a ressecção cirúrgica total é recomendada. Objetivos: descrever um caso de CEA refratário a tratamento clínico. Metódos: mulher, 45 anos, lombalgia há seis anos, com piora nos últimos meses e irradiação para membro inferior esquerdo (correspondente a L1). Sem demais alterações ao exame físico. A Ressonância magnética (RM) de coluna vertebral evidenciou lesão cística intravertebral a nível de T12 - L1, em situação póstero-lateral esquerda, provocando alargamento do forame, sugestivo de cisto epiduralaracnóideo. Resultados: Devido a falha do tratamento clínico inicial, a paciente foi submetida a hemilaminectomia de T12 - L1 à esquerda, ressecção do cisto e correção da falha dural. Evoluiu com controle álgico efetivo e RM de controle confirmou ausência de lesão residual. Conclusão: O CEA é mais comum em homens (4:1) e pode ser congênito ou adquirido. A topografia mais comum é a nível torácico (65%). Apresenta-se clinicamente com lombalgia, dor em membros inferiores e parestesias. A RM é o método diagnóstico de escolha e a intervenção cirúrgica é restrita aos casos sintomáticos ou refratários ao tratamento clínico e o prognóstico tende a ser excelente. Concluímos que, além de ser uma patologia rara e comumente assintomática, é essencial a adequada abordagem terapêutica para que ocorra cura completa, evitando quadros álgicos intensos e manifestações que cursem com drástica redução da capacidade funcional. Nível de evidência: IV. Tipo de Estudo: Série de casos.

RESUMEN Introducción: Entre las lesiones primarias que ocupan el espacio espinal, solo el 1% corresponde al quiste aracnoideo epidural (QAE). Esta patología generalmente es asintomática e identificada accidentalmente en pruebas de imagen. En casos sintomáticos, se recomienda la resección quirúrgica total. Objetivo: Describir un caso de QAE refractario al tratamiento clínico. Métodos: Mujer de 45 años tuvo dolor lumbar durante seis años y un aumento del dolor en los últimos meses, con irradiación a la extremidad inferior izquierda (que corresponde a L1). No se encontraron otras alteraciones en el examen físico. La resonancia magnética (RM) de la columna vertebral reveló una lesión quística intravertebral en el nivel T12-L1, en la posición posterolateral izquierda, causando agrandamiento del foramen y sugiriendo un quiste aracnoideo epidural. Resultados: Debido a la falla del tratamiento clínico inicial, la paciente fue sometida a hemilaminectomía T12-L1 izquierda, resección del quiste y corrección de la falla dural. Ella progresó con un control eficaz del dolor y la RM confirmó la ausencia de lesión residual. Conclusión: EL QAE es más común en hombres (4:1) y puede ser congénito o adquirido. La topografía más común es torácica (65%). Su presentación clínica es lumbalgia, dolor en las extremidades inferiores y parestesia. La RM es el método de elección para el diagnóstico y la intervención quirúrgica se limita a los casos que son sintomáticos o refractarios al tratamiento clínico, y el pronóstico tiende a ser excelente. Concluimos que, además de ser una condición rara y comúnmente asintomática, un abordaje terapéutico adecuado es esencial para una curación completa, evitando el dolor intenso y las manifestaciones que provocan una reducción drástica de la capacidad funcional. Nivel de evidencia: IV. Serie de casos.

Thecaloscopy: a novel method in spine surgery / Tecaloscopia: um novo método na cirurgia de coluna / Tecaloscopia: un nuevo método en la cirugía de la columna vertebral

ABSTRACT Objetive: Thecaloscopy is a less invasive method of exploration of the spinal subarachnoid space, using an ultra-thin, flexible endoscope and endoscopic fenestration of scars and adhesions. Thecalopscopy was used in Russian neurosurgery for the first time. Methods: Since 2009, we have operated on 32 patients with the following diagnoses: 17 - spinal adhesive arachnoiditis (8 - local forms, 9 - diffuse forms), 12 - spinal arachnoid cysts (7 - post-traumatic cysts, 5 - idiopathic cysts), and 3 - extramedullary tumors (thecaloscopic videoassistance and biopsy). In all cases, we performed exploration of subarachnoid space and pathologic lesion with endoscopic perforation of the cyst or dissection of adhesions using special instrumentation. The mean follow-up time in our group was 11.4 months. Results: Neurological improvement (mean 1.4 by the modified Frankel scale, 1.8 by the Ashworth spasticity scale) was seen in 87% of patients operated for spinal arachnopathies. Temporary neurological deterioration (mild disturbances of deep sensitivity) was seen in 9% of patients and managed successfully with conservative treatment. One patient (3.1%) was operated three times due to relapse of adhesions. There were no serious intraoperative complications (e.g. severe bleeding or dura perforation). Postoperative complications included one CSF leakage and one case of postoperative neuralgic pain. The mean hospitalization time was 7.6 days. Conclusion: According to our data, we conclude that thecaloscopy is efficient and safe method, and should be widely used for spinal arachnopathies, adhesive arachnoiditis and arachnoid cysts. Taking into account that adhesive spinal arachnoiditis is a systemic process, and that spinal arachnoid cysts may also be extended, thecaloscopy may be regarded as the most radical and less-invasive form of surgical treatment that currently exists in neurosurgery.

RESUMO Objetivo: A tecaloscopia é um método menos invasivo de exploração do espaço subaracnóideo, com um endoscópio flexível ultrafino e fenestração endoscópica de cicatrizes e aderências. A tecaloscopia foi usada pela primeira vez na neurocirurgia russa. Métodos: Desde 2009, operamos 32 pacientes com os seguintes diagnósticos: 17 aracnoidites adesivas espinais (8 formas locais e 9 formas difusas), 12 cistos aracnóideos espinais (7 cistos pós-traumáticos e 5 cistos idiopáticos) e 3 tumores extramedulares (vídeo-assistida por tecaloscopia e biópsia). Em todos os casos, realizamos a exploração do espaço subaracnóideo e da lesão com perfuração endoscópica do cisto ou dissecção de aderências usando instrumentação especial. O acompanhamento médio em nosso grupo foi de 11,4 meses. Resultados: A melhora neurológica (média 1,4 pela escala de Frankel modificada e 1,8 pela escala de espasticidade de Ashworth) foi observada em 87% dos pacientes operados devido a aracnopatias da coluna vertebral. A deterioração neurológica temporária (distúrbios leves da sensibilidade profunda) foi observada em 9% dos pacientes que foi tratada com sucesso pelo método conservador. Um paciente (3,1%) foi operado três vezes devido à recorrência de aderências. Não houve complicações intraoperatórias graves (por exemplo, sangramento grave ou perfuração da dura-máter, etc.). As complicações pós-operatórias incluíram um extravasamento de LCE e um caso de neuralgia pós-operatória. O período médio de hospitalização foi de 7,6 dias. Conclusão : De acordo com nossos dados, concluímos que a tecaloscopia é um método eficiente e seguro, e deve ser amplamente utilizado para aracnopatias espinais, aracnoidites adesivas e cistos aracnóideos. Considerando que a aracnoidite adesiva é um processo sistêmico e que os cistos aracnóideos da coluna vertebral também podem ser extensos, a tecaloscopia pode ser considerada como a forma mais radical e menos invasiva de tratamento cirúrgico existente atualmente em neurocirurgia.

RESUMEN Objetivo: La tecaloscopia es un método de exploración menos invasivo del espacio subaracnoideo con un endoscopio flexible ultrafino y fenestración endoscópica de cicatrices y adherencias. La tecaloscopia se utilizó en neurocirugía rusa por primera vez. Métodos: Desde 2009 operamos 32 pacientes con los siguientes diagnósticos: 17 aracnoiditis adhesivas espinales (8 formas locales y 9 formas difusas), 12 quistes aracnoideos espinales (7 quistes postraumáticos y 5 quistes idiopáticos) y 3 tumores extramedulares (asistida por video tecaloscópico y biopsia). En todos los casos se realizó la exploración del espacio subaracnoideo y lesión con perforación endoscópica del quiste o disección de adherencias mediante instrumentación especial. El seguimiento medio en nuestro grupo fue de 11,4 meses. Resultados: La mejoría neurológica (media 1,4 por la escala de Frankel modificada y 1,8 por la escala de espasticidad de Ashworth) se observó en el 87% de los pacientes operados debido a aracnopatías de la columna vertebral. Se observó deterioro neurológico temporal (alteraciones leves de la sensibilidad profunda) en el 9% de los pacientes, que fue tratada con éxito por el método conservador. Un paciente (3,1%) fue operado tres veces debido a la recurrencia de las adherencias. No hubo complicaciones intraoperatorias graves (por ejemplo, sangrado grave o perforación de la duramadre, etc.). Las complicaciones postoperatorias incluyeron una extravasación del LCR y un caso de neuralgia postoperatoria. El período promedio de hospitalización fue de 7,6 días. Conclusiones : De acuerdo con nuestros datos, concluimos que la tecaloscopia es un método eficiente y seguro, que debe ser ampliamente utilizado para aracnopatías espinales, aracnoiditis adhesivas y quistes aracnoideos. Teniendo en cuenta que la aracnoiditis adhesiva es un proceso sistémico y que los quistes aracnoideos de la columna vertebral también pueden ser extensos, la tecaloscopia puede ser considerada como la forma más radical y menos invasiva de tratamiento quirúrgico existente actualmente en neurocirugía.

[Clinical presentation of a dorsal epidural arachnoid cyst after an epidural anesthesia]. / Presentación clínica de quiste aracnoideo epidural dorsal posterior a anestesia epidural.

BACKGROUND: Arachnoid cysts are dural diverticula with liquid content similar to cerebrospinal fluid, with 1% occurring in the spinal cord. They locate mainly in the dorsal region of the thoracic spine, and are unusual causes of spinal cord compression. CLINICAL CASE: The case is presented of a previously healthy 15-year-old boy, with a 20-month history of spastic paraparesis that started apparently after epidural block for ankle osteosynthesis. There was decreased sensitivity and strength of the pelvic limbs and gradually presented with anaesthesia from T12 to L4 dermatomes, L5 and S1 bilateral hypoaesthesia and 4+/5 bilateral strength, in the L2 root and 2+/5 in L3, L4, L5, S1, hyperreflexia, Babinski and clonus, but with no alteration in the sacral reflexes. In the magnetic resonance it was diagnosed as an extradural arachnoid cyst from T6 to T9. The patient underwent a T6 to T10 laminotomy, cyst resection, dural defect suture, and laminoplasty. One year after surgery, the patient had recovered sensitivity, improvement of muscle strength up to 4+/5 in L2 to S1, and normal reflexes. CONCLUSIONS: After the anaesthetic procedure, increased pressure and volume changes within the cyst could cause compression of the spinal cord, leading to symptoms. Despite being a long-term compression, the patient showed noticeable improvement.

[Arachnoid cysts of the central nervous system. Algorithms and recommendations for management]. / Quistes aracnoideos del sistema nervioso central. Algoritmos y recomendaciones generales de manejo.

The symptoms related to the presence of arachnoid cysts in the Central Nervous System depend on the size of the cyst and its growth rate, its location and, in some cases, the associated CSF dynamic disorder. Sometimes there is acute clinical presentation due to cyst rupture or acute bleeding. Although it is generally accepted that asymptomatic or paucisymptomatic cysts do not require surgical treatment, there is no consensus on the therapeutic approach of choice in symptomatic cases. The aim of this paper is to review the literature, analyzing the pros and cons of the three main surgical options (microsurgery, neuroendoscopy, and CSF shunt) based primarily on the location of the cyst. Although treatment must be always individualized, basic management recommendations may be offered.

[Epidemiology and classification of arachnoid cysts in children]. / Epidemiología y clasificación de los quistes aracnoideos en niños.

The prevalence of arachnoid cysts in children is 1-3%. They are more frequent in boys. They can be located intracranially or in the spine. Intracranial cysts are classified as supratentorial, infratentorial, and supra-infratentorial (tentorial notch). Supratentorial are divided into middle cranial fossa, convexity, inter-hemisferic, sellar region, and intraventricular. Infratentorial are classified into supracerebellar, infracerebellar, hemispheric, clivus, and cerebellopontine angle. Finally spinal arachnoid cysts are classified taking into account whether they are extra- or intradural, and nerve root involvement.

[Arachnoid cysts: Embriology and pathology]. / Quistes aracnoideos: embriología y anatomía patológica.

There is still great controversy surrounding the origin of the arachnoid cyst. The most accepted theory in the case of congenital cysts explains how they are formed from an anomalous development of the arachnoid membrane, which is unfolded allowing the accumulation of cerebrospinal fluid inside and creating a cyst. This theory seems to explain the origin of convexity and sylvian cistern arachnoid cysts, whereas those in other locations might be due to other mechanisms. In the anatomopathological analysis, the arachnoid cyst wall can be seen as having few differences from normal, although thickened due to an increase quantity of collagenous material. A description of the embryological development of the arachnoid layer and cyst formation is presented, describing the main anatomopathological findings.

Spinal extradural arachnoid cysts / Cistos aracnóideos extradurais da coluna / Quistes aracnoideos extradurales de la columna

OBJECTIVE: Extradural arachnoid cysts (EACs) are rare causes of spinal cord compression and cauda equina. These benign lesions appear in the literature mainly as single case reports. In this article, we present the largest series found in literature, with four new cases of spinal extradural arachnoid cysts. The characteristic imaging features, details of surgical steps and strategies to prevent postoperative kyphosis in this cystic pathology will be discussed.

OBJETIVO: Os cistos aracnóideos extradurais (EAC) são causa rara de compressão da medula espinal e de cauda equina. Essas lesões benignas aparecem na literatura principalmente como relatos de casos isolados. Neste artigo, é apresentada a maior série encontrada na literatura, com quatro novos casos de cistos aracnóideos extradurais da coluna. DISCUSSÃO: São discutidas as características das imagens, os detalhes dos passos cirúrgicos e as estratégias para prevenir a cifose pós-operatória nessa patologia cística.

OBJETIVO: Los quistes aracnoideos extradurales (EAC) son causa rara de compresión de la médula espinal y de cauda equina. Estas lesiones benignas aparecen en la literatura principalmente como relatos de casos aislados. En este artículo, es presentada la mayor serie encontrada en la literatura, con cuatro nuevos casos de quistes aracnoideos extradurales de la columna. Son discutidas las características de las imágenes, los detalles de los pasos quirúrgicos y las estrategias para prevenir la cifosis postoperatoria en esa patología quística.