First-in-human endovascular treatment of hydrocephalus with a miniature biomimetic transdural shunt.

Surgical ventriculoperitoneal shunting remains standard treatment for communicating hydrocephalus, despite persistently elevated infection and revision rates. A novel minimally invasive endovascular cerebrospinal fluid (CSF) shunt was developed to mimic the function of the arachnoid granulation which passively filters CSF from the central nervous system back into the intracranial venous sinus network. The endovascular shunt is deployed via a femoral transvenous approach across the dura mater into the cerebellopontine angle cistern. An octogenarian with intractable hydrocephalus following subarachnoid hemorrhage underwent successful endovascular shunting, resulting in swift intracranial pressure reduction from 38 to <20 cmH2O (<90 min) and resolution of ventriculomegaly. This first successful development of a percutaneous transluminal venous access to the central nervous system offers a new pathway for non-invasive treatment of hydrocephalus and the potential for intervention against neurological disorders.

A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description / Abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno: descrição passo a passo

Abstract Introduction: Arachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal. Objective: To investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal. Methods: Minimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging. Results: The mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area. Conclusion: The results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.

Resumo Introdução: O cisto aracnóide no conduto auditivo interno é uma doença bastante rara, mas, devido à sua ação compressiva sobre os nervos deste local, ele deve ser removido cirurgicamente. Várias técnicas cirúrgicas foram propostas, mas ninguém utilizou a abordagem retrosigmoide minimamente invasiva assistida por endoscopia para a sua remoção. Objetivo: Investigar a viabilidade do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção cirúrgica de cistos aracnóides no conduto auditivo interno. Método: A abordagem retrosigmoide minimamente invasiva assistida por endoscopia permite o acesso ao conduto auditivo interno através de uma abordagem retrosigmóide minimamente invasiva que combina o uso de um microscópio e um endoscópio. É realizada em seis etapas: do tecido mole, óssea, dura-máter, do ângulo pontocerebelar (realizado com um endoscópio e um microscópio), remoção e fechamento assistidos por endoscópio-microscópico. Testamos a abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno em duas cabeças de cadáveres humanos (espécimes) de indivíduos afetados por distúrbios auditivos-vestibulares e com cistos aracnóides no conduto auditivo interno confirmado por imagem de ressonância magnética. Resultados: A lesão foi removida completamente e com sucesso nos dois espécimes sem dano aos nervos e/ou vasos na área cirúrgica. Conclusão: Os resultados do nosso estudo são encorajadores e apoiam a viabilidade do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno. Embora mais estudos clínicos in vivo sejam necessários para confirmar a precisão e a segurança do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para essa cirurgia específica, nosso grupo utilizou com sucesso a abordagem retrosigmoide minimamente invasiva assistida por endoscopia no tratamento da síndrome compressiva microvascular, remoção de schwannoma e ressecção do nervo vestibular.

A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description.

INTRODUCTION: Arachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal. OBJECTIVE: To investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal. METHODS: Minimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging. RESULTS: The mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area. CONCLUSION: The results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.

Melanocitoma meníngeo del ángulo pontocerebeloso: claves imagenológicas para su abordaje / Cerebellopontine meningeal melanocytoma: keys for imaging diagnostic approach

Resumen: Las lesiones del ángulo pontocerebeloso (APC) representan el 6 al 10% de las neoplasias intracraneales, siendo los schwannomas vestibulares y meningiomas los más comunes. Sin embargo, hasta el 15% pueden ser otras lesiones, entre ellas las derivadas a partir de restos de células melanocíticas presentes en las leptomeninges. El diagnóstico diferencial de las patologías tumorales del APC es extenso, siempre teniendo en cuenta las lesiones más comunes. Sin embargo, cuando las características radiológicas no son las esperadas, el enfoque debe orientarse hacia las lesiones inusuales, poniendo en contexto las diferentes estirpes celulares que pueden dar origen a las neoplasias en esta localización, como las neoplasias melanocíticas. Se presenta el caso de un masculino de 74 años con síndrome cerebeloso de tórpida evolución, al cual se le realiza RM de cerebro contrastada, identificando una lesión de base dural en el APC izquierdo, con hiperintensidad de señal en T1 e hipointensidad en T2, atípico para las lesiones más comunes en esta región, que sugiere su contenido melanocítico.

Abstract: Cerebellopontine angle tumors (CPA) represent approximately 6 to 10% of intracranial tumors. Vestibular Schwannomas and meningiomas are the most common, however up to 15% can be of other origin, including from melanocytes derived from the neural crest. The differential diagnosis of CPA pathologies is extensive, always taking into account the most common ones. However, if the radiological characteristics are not the expected, the approach should be directed towards unusual lesions, putting into context the different cell lines that can give rise to the neoplasm at this location, such as melanotic neoplasms. We present a case of a 74-year-old male, who presented with a cerebellar syndrome. Due to an atypical clinical evolution, a contrast enhanced head MRI was performed, revealing a dural based tumor on the left CPA, which was hyperintense on T1 and hypointense on T2 weighted sequences, which is not expected from the common lesions at this region and suggested it's melanotic content.

Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review.

Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.

Angular and metric analysis of the neural structures in the cerebellopontine angle.

INTRODUCTION: The cerebellopontine angle (CPA) is a subarachnoid space in the lateral aspect of the posterior fossa. In this study, we propose a complementary analysis of the CPA from the cerebellopontine fissure. METHODS: We studied 50 hemi-cerebelli in the laboratory of neuroanatomy and included a description of the CPA anatomy from the cerebellopontine fissure and its relationship with the flocculus and the 5th, 6th, 7th, and 8th cranial nerves (CN) origins. RESULTS: The average distance from the 5th CN to the mid-line (ML) was 19.2 mm, 6th CN to ML was 4.4 mm, 7-8 complex to ML was 15.8 mm, flocculus to ML was 20.5 mm, and flocculus to 5th CN was 11.5 mm, additionally, and the diameter of the flocculus was 9.0 mm. The angle between the vertex in the flocculus and the V CN and the medullary-pontine line was 64.8 degrees. DISCUSSION: The most common access to the CPA is through the retrosigmoid-suboccipital region and this approach can be done with the help of an endoscope. The anatomy of origins of neural structures tends to be preserved in cases of CPA lesions. CONCLUSION: Knowledge of the average distances between the neural structures in the cerebellar-pontine fissure and the angular relationships between these structures facilitates the use of surgical approaches such as microsurgery and endoscopy.

Non-schwannomatosis lesions of the internal acoustic meatus-a diagnostic challenge and management: a series report of nine cases.

Vestibular schwannomas (VS) are the most common lesions of cerebellopontine angle (CPA) corresponding to 76-91 % of the cases. Usually, these lesions present typical CT and MRI findings. Non-schwannomatous tumors restricted to the internal auditory meatus (IAM) are rare and their preoperative radiological diagnosis may be difficult. This article describes nine surgically treated intrameatal non-schwannomatous lesions (NSL) and reviews the literature. In the last 16 years, a total of 471 patients with diagnosis of VS were operated on in our department. Preoperatively, 42 patients had diagnosis of intrameatal schwannomas, but surgery revealed in nine cases NSL (3 meningiomas, 3 arachnoiditis/neuritis, 1 cavernoma, 1 vascular loop, and 1 arachnoid cyst). Most frequent symptoms presented by patients with NSL were hearing loss 89 % (8/9) of patients, tinnitus 78 % (7/9), and vertigo 33 % (3/9). Almost all lesions (8/9) presented MRI findings of isointense signal in T1W with contrast enhancement. The only exception was the arachnoid cyst with intracystic bleeding, which was hyperintense in T1W that is not enhanced with contrast. This series shows an occurrence of 21.4 % of non-schwannomatous tumors in 42 cases of lesions restricted to the IAM. Whenever a solely intrameatal enhanced tumor is detected, it is necessary to think about other diagnostic possibilities rather than VS. Therapeutic management may be changed, specially if radiosurgical treatment is considered.

Combined pre- and subtemporal transtentorial approach for epidermoid cysts of the cerebellopontine angle.

OBJECTIVE: Epidermoid cysts of the cerebellopontine angle (CPA) can be a surgical challenge for the pediatric neurosurgeon. Ideally, total removal must be achieved; however, occasional adhesions of these tumors to vital neurovascular structures and extension far beyond the midline may preclude their total removal. The aims of this article are to present an alternative surgical approach to these lesions and to provide the rationale for this technique. MATERIAL AND METHODS: A 16-year-old boy was admitted to our pediatric neurosurgery department with a 1-year history of nonspecific headaches. His neurological examination showed right-sided dysmetria and gait ataxia. Magnetic resonance scans showed a space-occupying lesion on the right CPA with low intensity on T(1)-weighted images and high intensity on T(2)-weighted images. RESULTS: Craniotomy for tumor excision via pre- and subtemporal transtentorial approach was performed disclosing a 3.5 × 3 × 2.8-cm(3) well-encapsulated tumor, which was confirmed to be an epidermoid cyst. The postoperative course was uneventful. CONCLUSIONS: A combined pre- and subtemporal approach utilizes a wide opening of the tentorium and the option of supratentorial retraction of the cerebellum to provide an excellent angle of approach to CPA lesions involving the anterolateral aspect of the brain stem in children.

Cerebellopontine angle subependymoma without fourth ventricle extension: an uncommon tumor in a rare location.

Subependymomas are benign tumors that occur predominantly in the ventricular system. We describe a case of a 57-year-old man with a large cerebellopontine angle (CPA) tumor which expanded into the jugular foramen. Complete surgical excision of the tumor was achieved through a retrosigmoid approach and the histopathological diagnosis was subependymoma. Subependymomas located exclusively in the CPA without extension into the fourth ventricle are extremely rare. The mainly pathological features and the difficulty in correctly diagnosing these cases preoperatively, even with MRI, are discussed.

Image-guided surgical planning using anatomical landmarks in the retrosigmoid approach.

OBJECTIVE: The suboccipital lateral or retrosigmoid approach is the main neurosurgical approach to the cerebellopontine angle (CPA). It is mainly used in the treatment of CPA tumors and vascular decompression of cranial nerves. A prospective study using navigation registered with anatomical landmarks in order to identify the transverse and sigmoid sinuses junction (TSSJ) was carried out in a series of 30 retrosigmoid craniotomies. The goal of this study was to determine the accuracy of this navigation technique and to establish the relationship between the location of the asterion and the TSSJ. METHODS: From March through November 2008, 30 patients underwent a retrosigmoid craniotomy for removal of CPA tumors or for surgical treatment of neurovascular syndromes. Magnetic resonance imaging (MRI) T1 sequences with gadolinium (FSPGR with FatSst, 1.5 T GE Signa) and frameless navigation (Vector vision, Brainlab) were used for surgical planning. Registration was performed using six anatomical landmarks. The position of the TSSJ indicated by navigation was the landmark to guide the craniotomy. The location of the asterion was compared with the position of the TSSJ. After craniotomy, the real TSSJ position was compared with the virtual position, as demonstrated by navigation. RESULTS: There were 19 cases of vestibular schwannomas, 5 petroclival meningiomas, 3 trigeminal neuralgias, 1 angioblastoma, 1 epidermoid cyst and 1 hemifacial spasm. In all cases, navigation enabled the location of the TSSJ and the emissary vein, with an accuracy flaw below 2 mm. The asterion was located directly over the TSSJ in only seven cases. One patient had a laceration of the sigmoid sinus during the craniotomy. CONCLUSIONS: Navigation using anatomical landmarks for registration is a reliable method in the localization of the TSSJ for retrosigmoid craniotomies and thereby avoiding unnecessary sinus exposure. In addition, the method proved to be fast and accurate. The asterion was found to be a less accurate landmark for the localization of the TSSJ using navigation.

Cerebellopontine angle lesions in children.

BACKGROUND: Cerebellopontine angle (CPA) lesions are more commonly found in adults in which they account for 5-10% of all intracranial tumors. However, they are uncommon in children, with an incidence of only 1%. MATERIALS AND METHODS: This is a review of the management of CPA lesions in children admitted to the Hospital Nacional de Pediatría "Profesor Doctor Juan P. Garrahan" (Argentine National Pediatrics Hospital "Professor Juan P. Garrahan") between January 1988 and December 2003. RESULTS: The series included 30 children with 33 CPA lesions, 20 arising from the subarachnoid space of the CPA and 13 from the vicinity and growing mainly into the CPA. Twenty-seven tumors were located in the left CPA (82%) and six (12%), on the right. Ten of the 30 patients developed hydrocephalus, but only three of these required treatment. All patients underwent retrosigmoid suboccipital craniotomy and microsurgical resection. Gross total removal was achieved in 12 cases, subtotal in 18, and fenestration of the cyst wall in the three arachnoid cysts. Ten patients have no sequelae, ten have mild deficit, three have severe deficits, and seven have died. CONCLUSION: The CPA is a rare location for lesions in children, with clear predominance on the left side. Benign lesions are more frequent. Even though schwannoma is the most frequently found lesion, the histology varies widely.

Cerebellopontine angle cysticercus and concurrent vascular compression in a case of trigeminal neuralgia.

The authors present the case of a 59-year-old woman with an 8 months history of lancinating pain and hyphestesia on the right side of the face along with hearing impairment. She had poor tolerance to carbamazepine. A non-enhancing cystic image was observed at the right cerebellopontine angle on magnetic resonance imaging. The patient underwent surgery. Through a right retromastoid minicraniectomy and under microscopic magnification the VII and VIII cranial nerve complex was found involved by multiple adhesions around a cysticercus. After the cyst was removed a loop of the anteroinferior cerebellar artery was identified compressing the V right nerve at its root entry zone. Decompression was performed by the insertion of a Teflon implant. The postoperative course was uneventful and trigeminal neuralgia (TN) disappeared after surgery. Five previous cases of cranial nerve hyperactive dysfunction syndromes, four of trigeminal neuralgia and one of hemifacial spasm associated to cerebellopontine angle cysticercosis are briefly commented. We suggest that in some of these cases microvascular compression was probably present, and during surgery of cerebellopontine angle cysticercus by either trigeminal neuralgia or hemifacial spasm, vascular compression must be carefully searched and treated when found.

[Combined supra and infratentorial presigmoideo approach for lesions of the petrous and clival regions]. / Abordaje combinado suprainfratentorial presigmoideo en las lesiones de la región petrosa y clival.

INTRODUCTION: Petrous and petroclival lesions may be surgically treated with combinations of suprainfratentorial presigmoideo approach and microsurgical techniques. OBJECTIVE: To demonstrate the utility and to present our surgical experiences with this approach. PATIENTS AND METHODS: Thirteen patients with lesions of the clival, petrous region and of the cerebellopontine angle with extension toward the anterior portion of brainstem were taken to the operative room. There were nine women and four men. Eleven were adults and two children. The main clinical manifestations were headache (100%), dysfunction of cranial nerves (90%), ataxia (90%) hemiparesis (75%). There was papiledema in 45%. Petroclival meningiomas and schwannomas were the more frequent lesions. There were three patients with intraxial brainstem tumors and two arteriovenous malformations. There were not aneurysms. We performed nine retrolaberintic, three translaberintic and one transcochlear approach. RESULTS: There was not severe incapacity, vegetative or dead patients. The surgical complications were facial nerve paresis (31%), cerebrospinal fluid leak (23%), decreased gag reflex (15%), abducens nerve paresis, hemiparesis and Claude Bernard Horner syndrome (8%). 50% of these complications disappeared three months later. CONCLUSIONS: The suprainfratentorial presigmoidal approach and their surgical variations could be utilized to obtaining a low morbimortality, in the treatment of different neoplasm and vascular diseases of the petrous and petroclival region.

Late metastasis of breast adenocarcinoma into internal auditory canal and cerebellopontine angle: case report.

A case of metastasis of breast adenocarcinoma into the internal auditory canal (IAC) and cerebellopontine angle (CPA) is presented, which appeared 16 years after primary tumor had been treated by surgery and radiation therapy. The 66-year old patient was considered cured from the primary disease, when she started with a rapidly developing hearing loss and intermittent facial palsy. Magnetic resonance image (MRI) displayed an intra- and extracanalicular tumor mass, which radiologically resembled a vestibular schwannoma. Surgery was performed and histopathological studies showed an adenocarcinoma compatible with breast origin. Metastasis is a rare occurrence within the IAC and CPA. Clinical history of severe facial palsy will rise suspicion of malignant tumor in spite of the radiological findings.

[Aneurysm of the anterior inferior cerebellar artery: case report]. / Aneurisma da artéria cerebelar ântero-inferior: relato de caso.

The intracranial aneurysms of the posterior circulation have been reported between 5 and 10% of all cerebral aneurysms and the aneurysms of the anterior inferior cerebellar artery (AICA) are considered rare, can cause cerebello pontine angle (CPA) syndrome with or without subarachnoid hemorrhage. Since 1948 few cases were described in the literature. We report on a 33 year-old female patient with subarachnoid hemorrhage due to sacular aneurysm of the left AICA. She was submitted to clipage of the aneurysm without complications.

[Lipoma of the cerebellopontine angle: case report]. / Lipoma do ângulo pontocerebelar: relato de caso.

Lipoma of the cerebellopontine angle is a very rare tumor. We report the case of a 14-years-old female, with left side deafness during three years, associated with headache. CT scan showed an hypodense mass, without enhancement at the cerebellopontine angle. The patient was treated surgically by left retrosigmoid approach. The lesion involved the eighth and seventh cranial nerves and only a partial removal was performed. The postoperative course was uneventful. She had no more headache; the deafness of the left side remained unchanged. Asymptomatic lipoma of the cerebellopontine angle can be treated conservatively, although those with progressive symptoms should be treated surgically, with total or partial remove based on their neurovascular involvement.

Anatomía microquirúrgica y microvascular de la artería antero-cerebelosa inferior (AICA) / Microsurgical and microvascular anatomy of the anterior inferior cerebellar artery (AICA)

El conocimiento exacto de la anatomía microquirúrgica y microvascular de la arteria ántero-cerebelosa inferior y de sus variantes es importante en el manejo quirúrgico de patología localizada a la porción medial del ángulo pontocerebeloso. De las patologías relacionadas con la arteria ántero-cerebelosa inferior están las neoplasias, síndromes de compresión microvascular de las estructuras neurales, aneurismas, malformaciones arteriovenosas y enfermedades infecciosas. En el manejo quirúrgico de la porción medial del ángulo pontocerebeloso es importante el conocimiento de las técnicas de cirugía de base de cráneo y de microcirugía. Palabras clave: arteria ántero-cerebelosa inferior (AICA), anatomía microquirúrgica, anatomía microvascular, ángulo pontocerebeloso

Preservación de la función auditiva en la cirugía de los tumores del conducto auditivo interno y el ángulo pontocerebeloso / Preservation of the auditive function in the tumors surgery of external ear canal and cerebellopontine angle

Las lesiones tumorales a nivel del conducto auditivo interno y el ángulo pontocerebeloso son casi siempre benignas y su predominio está dado primariamente por los neurinomas (schwannomas) del nervio acústico con origen en su rama vestibular, los meningiomas originados en las envolturas meníngeas adyacentes y los colesteatomas provenientes del hueso temporal. Inicialmente, cuando los tumores son pequeños, estos crecen en el conducto auditivo interno y en el espacio real es el ángulo pontocerebeloso, sin dar mayores manifestaciones clínicas. En estas etapas iniciales puede haber o no, pérdidas auditivas moderadas, sensación de inestabilidad corporal y acúfenos. Estos tumores, por ser de poca manigtud, puede pasar desapercibidos para el paciente y peor aún, para el médico quien puede restarle importancia por su poca consistencia. Al crecer estos tumores, los síntomas se hacen evidentes por la compresión neural, terminado en síntomas severos como hipertensión endocraneana, etaxia y muerte. El alto índice de sospecha clínica que conduzca a un diagnóstico precoz, es la base fundamental para la detección temprana de estos tumores. En la actualidad, se cuenta con una batería de pruebas otoneourológicas, tales como el examen audiológico completo y el examen vestibular, destacando la audiometría de tallo cerebral por potenciales evocados, exploración de alta fidelidad para el diagnóstico de una lesión retrococlear. Pero fundamentalmente con la imagen por resonancia magnéctica que permite diagnósticar precozmente lesiones hasta de 2mm de diámetro. El desarrollo de minuciosas técnicas microquirúrgicas a nivel del conducto auditivo interno y ángulo pontocerebeloso, permite hoy en día al otoneurocirujano, abordar quirúrgicamente estos tumores cuando aún no han producido un déficit neurológico significativo y preservar la función cada vez en un mayor porcentaje de casos. El abordaje quirúrgico por la vía de la fosa craneana media y por la vía retrosigmoidea, permiten en la actualidad, preservar la función auditiva al no tocar el oido interno. El rsultado satisfactorio está supeditado a una muy buena selección del caso y al logro de la preservación de la vascularización del oido interno. Este trabajo comenta las exploraciones clínicas más adecuadas para un diagnóstico precoz, las vías de abordaje quirúrgico con sus posibilidades y limitaciones, y analiza las probabilidades de lograr la preservación de la función.

Localizaçäo incomum do papiloma de plexo coróide: relato de caso / An unusual presentation of choroid plexus papilloma: case report

Os autores relatam um caso de papiloma de plexo coróide de localizaçao incomum, no ângulo ponto-cerebelar, com quadro de hipertensao intracraniana, em adulto jovem. Sao analisados a incidência, fisiopatogenia e diagnóstico destes tumores. A revisao da literatura disponível mostrou tratar-se do segundo caso publicado na bibliografia nacional.