El punto esfenoselar: ubicación antómica y utilidad en 34 casos operados por vía endonasal transesfenoidal / The sphenoselar point: antomic location and utility in 34 cases operated on by the transsphenoidal endonasal route

Objetivo. Determinar la relación entre la localización de la cara anterior del seno esfenoidal y la superficie externa del cráneo, ubicando el punto esfenoselar para orientar el abordaje endonasal. Método. Se utilizaron cuatro cabezas de cadáveres adultos, fijadas en formol e inyectadas con silicona coloreada, y diez cráneos secos. Los cráneos fueron divididos por la mitad y se ubicó el punto esfenoselar, que corresponde a la intersección de una línea vertical que pasa por la pared anterior del seno esfenoidal con una línea horizontal que pasa por el piso de la silla turca. Luego se estudió a relación entre dicho punto y la superficie externa del cráneo, utilizando un torno y dirigiendo la mecha desde el punto esfenoselar ateralmente. Así, se realizaron mediciones entre la representación externa del punto esfenoselar y el conducto auditivo externo. Resultados. El punto esfenoselar se ubicó en la superficie externa del cráneo a un promedio de 4,01 cm por delante y 2,33 cm por arriba del conducto auditivo externo. Dicho punto fue útil durante la cirugía, ya que permitió orientar la dirección del abordaje paralelo al piso del quirófano. Conclusión. Con la ayuda del punto esfenoselar, se pudo trazar imaginariamente la dirección de la vía endonasal, disminuyendo el riesgo de desviación rostrocaudal del abordaje.

Objective. To determine the location between the anterior wall of the sphenoid sinus and the external surface of the skull, localizing the spheno-sellar point as a guide in the endonasal approach. Method. Four formalin-fixed adult cadaveric heads, injected with colored silicon, and ten dry skulls, were used. The skulls were divided in the midline and the spheno-sellar point, that corresponds to the intersection between a vertical line that cross through the anterior wall of the sphenoid sinus and an horizontal line that cross through the floor of the sella turcica, was located. Then, the relationship between the spheno-sellar point and the external surface of the skull was studied, using drill and pointing the tip from the spheno-sellar point laterally. Thusmeasures between the external representation of the sphenosellar point and the external additive meatus were done. Results. The spheno-sellar point is located in the external surface of the skull 4.01 cm ahead and 2.33 cm above the external auditive meatus. That point was useful during surgery in order to guide the approach parallel to the floor of the operating room. Conclusion. With the help of the spheno-sellar point, we could trace the imaginary direction of the endonasal way, decreasing the risk of rostrocaudally deviation during the approach

El foramen yugular: anatomia microquirurgica y abordajes / Yugular foramen: microsurgical anatomy and approaches

Objective: to describe the anatomy and the operative approaches to the jugular foramen. Method: twenty dry heads and four formalin-fixed adults heads injected with silicon were examined. We performed measurements of the jugular foramen in the dry heads and the operative approaches in a stepwise manner in the formalin - fixed heads. Results: the jugular foramen is divided into three compartments: the petrosal (inferior petrosal sinus), the intrajugular (glossopharyngeal, vagus, and accesory nerves) and the sigmoid (sigmoid sinus) parts. In 65 por ciento dry heads the right foramen was larger than the left, in 5 por ciento equal, and in 30 por ciento smaller than the left. The length of the jugular foramen was 14.29mm from the endocranial view and 15,10mm from the exocranial view. The approaches to the jugular foramen are the retrosigmoid, the far-lateral paracondylar, the transmastoid infralabyrinthine and the preauricular infratemporal. Conclusion: the operative approaches to the jugular foramen can be categorized into three groups: 1)a posterior group directed through the posterior cranial fossa, 2) a lateral group directed through the mastoid bone, and 3) an anterior group directed through the tympanic bone

Analisis de la incidencia de la paralisis del nervio motor ocular comun en una poblacion neuroquirurgica. Correlacion clinica, anatomica e imagenologica / Incidence analysis of third nerve palsy in a neurosurgical poblation. Clinical, anatomical and image correlation

Objective: to describe the incidence and the different etiologies of oculomotor palsy in neurosurgical patients. Methods: Hospital records from the last 3 years were retrospectively reviewed. Five formalin-fixed adults heads were examined using X6 to X40 magnification. A correlation between clinical findings, anatomical studies and MRI images was performed. Results: medical records from 382 patients operated on at our department were reviewed. Of these, 16 patients underwent complete oculomotor palsy before brain surgery. Two patients had a mesencephalic tumor, 6 patients underwent uncal herniation due to a fast-growing intracranial mass, one patient had a superior cerebellar artery aneurysm, 3 patients had a posterior communicating artery aneurysm, one patient had a cavernous sinus meningioma. An analysis of the clinical, anatomical and MRI/ angiography data of 5 cases are presented in this study. Conclusion: oculomotor palsy is a relatively common finding in neurosurgical practice. The fact that it can be caused by different etiologies should be considered in order to arrive to the appropiate diagnosis and treatment. Anatomical knowledge of third nerve is very important when dealing with oculomotor palsy

Meningiomas quisticos: presentacion de 3 casos / Cystic meningiomas: report of three cases

Objective: to describe 3 cases of intracranial cystic meningioma. Description: Case 1 (male, 24 years old), with headache, vomits, right homonymous hemianopsia and conductal disorder, in the last 2 months. MRI: left parieto - occipital cystic tumor. Case 2 (male, 56 years old) with generalized siezure, in the last month. MRI. left parietal cystic tumor. In the three cases, the suspected diagnose was glioma. Intervention: in the 3 cases a craniotomy was perfomed, with total (cases 2 and 3) or partial resection of the tumor (case 1). The cysts were intratumoral (case 2) and extratumoral (cases 1 and 3). Pathology informed meningioma. The outcome was favorable, with no complications. Conclusion: It is very difficult to make a diagnosis of cystic meningioma before surgery procedure and pathological analysis. During surgery they behave as solid meningiomas

Glioblastoma multiforme de fosa posterior. Presentacion de un caso / Posterior fosa multiform glioblastoma

Objective: to report a case of glioblastoma multiforme (GBM) of the posterior fossa. Description: male, 53 years old, with a clinical presentation of dizziness and diplopia. MRI: posterior fossa tumor in the left cerebellar hemisphere, with an extension to the peduncle, brain stem and cerebellopontine angle. Intervention: a subtotal ressection was performed through a suboccipital craniotomy. Pathology informed GBM. After surgery the patient completed the treatment with radiotherapy (60Gy). The outcome was favorable. Conclusion: the preoperative diagnosis of a posterior fossa GBM is difficult because its a extremely rare localization, nevertheless it must be suspected

Hematoma subdural subagudo y cronico: tratamiento quirurgico en 176 pacientes. Nuestra experiencia / Subacute and chronic subdural hematomas: surgical treatment in 176 patients. Our experience

Objective: to describe our surgical experience in suvacute and chronic subdural hematomas. Method: 176 patients with subacute or chronic subdural hematomas were operated between June 1998 and May 2003. Hospital records were used to ascertain data. We did a comparative analysis of the different types of surgical procedures performed. Results: the surgical procedure commonly performed was a burrhole craniostomy with subdural closed - system drainage (66 por ciento). This procedure was associated with a low rate of complications and reoperations, in comparison with the burr hole craniostomy or the craniostomy without subdural closed-system drainge. Global recurrence rate was 13 por ciento and 20,4 por ciento of the cases required reoperation. Clinical improvement rate was 72,3 por ciento. Conclusion: In our cases, burr hole craniostomy with closed-system drainge was the method of choice for the initial treatment in subacute and chronic subdural hematomas. Craniotomy should be reserved for those cases of recurrence or residual hematoma

Cisterna Ambiens: anatomia microquirurgica y abordajes / Ambient cistern: microsurgical anatomy and approaches

Objective: to define the limits of the ambient cistern and to show the different ways to approach that space. Method: four formalin-fixed adults were examined using X6 to X40 magnification. The vessels were filled with colored silicon. Results: The ambient cistern is located in both sides of the mesencephalon; it is in relation with the crural cistern in front, the cuadrigeminal cistern behind and the cerebellopontine cistern bellow. The diferent approaches to the ambient cistern are; 1)transchoroidal approach, 2)infraoccipital transtentorial approach and 3) supracerebellar transtentorial approach. Conclusion: the transchoroidal, infraoccipital transtentorial and supracerebellar transtentorial are options when there are a lesion in the ambient cistern

Carcinomatosis meningea. Comunicacion de dos casos / Meningeal carcinomatosis. Report 2 of cases

Objective: To describe 2 cases of leptomeningeal carcinomatosis. Description: Case 1 (24 years old female) complained of right ciatica and wakness in the last 15 days, with urinary retention. MRI showed a conus medullaris lesion that enhanced with gadolinium. Case 2 (47 years old female) with a previous history of a high grade B-cell limphoma, complaneid of astenia, anorexia and radicular pain. Lately she developed neurological deterioration, VII nerve palsy, urinary retention and seizures. A cisternal puncture was positive for neoplastic cells. Intervention: In case 1 surgery was performed and pathology infrmed high grade glioma. After 30 days she developed a meningeal syndrome with bilateral VI and VII cranial nerves paresis and neurological deterioration. Lumbar puncture was positive for neoplastic cells. She died after 15 days. Case 2 received intrathecal chemotherapy. Conclusion: Patients with extraneural malignat tumors and high grade tumors of the nervous system that refer signs and symptoms of a meningeal dissemination, meningeal carcinomatosis must be suspected

Pseudotumor inflamatorio idiopatico orbitario bilateral con extension intracraneana. Comunicacion de un caso / Bilateral idiopathic orbital inflammatory pseudotumor with intracranial extension. Case report

Objective: To describe a case of bilateral idiopathic orbital inflammatory pseudotumor with intracranial extension. Description: a 46 years old female patient complaneid of right eye blurred vision and amaurosis since the past 9 months. Examination revealed: right eye 7/10 visual acuity and exophthalmos; left eye amaurosis and optic atrophy: CT scan and MRI showed a bilateral intraorbital and intracanal lesions with left intracranial extension. Intervention: Through a left frontal approach the left intracranial extension eas removed and the optic nerve was decomprssed. Intraoperative biopsy revealed a linfoproliferative lesion. Surgery ended and definitive pathology was informed as an inflammatory pseudomotor. The patient received corticoids with a good response. Conclusion: The presence of bilateral intraorbital lesions with intracranial extension, should force us too think about inflammatory pseudotumors

Neurinoma glosofaringeo: comunicacion de un caso / Glossopharyngeal neurinoma: case report

Objective: To describe a patient with a IX cranial nerve neurinoma of the cerebellopontine angle. Description: A 29 years old woman complained of headache and decreased hearing of the right ear during the last two years. MRI showed a lesion in the right cerebellopontine angle. Intervention: The patient was operated through a retrosigmoid approach. During surgery we realized that the lesion was related to the glossopharyngeal nerve. The tumor was totally resected, without postoperative morbidity. The pathologist informed schwanoma. Conclusion: The possibility of a glossopharyngeal schwannoma with auditive loss is possible

Anatomia microquirurgica del segmento P1 de la arteria cerebral posterior / Microsurgical anatomy of the P1 posterior cerebral artery segment

Objective: This study was conducted to clarify the anatomy of the posterior cerebral artery P1 segment. Methods: Four formalin-fixed adults heads were examined using X6 to X40 magnification. The vessels were filled with colored silicon. Results: The branches arising from the P1 are: 1) the posterior thalamoperforating arteries; 2) the short and long circumflex branches; 3) the medial posterior choroidalartery; and 4)the meningeal branch of Davidoff and Schechter. Conclusion: the correct knowledge of the anatomy of the P1 segment of the posterior cerebral artery is very important in the treatment of lesions located in the interpeduncular cistern