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Gross-total resection of foramen magnum meningiomas remains the gold standard of treatment and should be performed whenever possible. The transcondylar approach (and its variations) represents the most used approach for meningiomas located in the lateral or anterior borders of the foramen magnum. Endoscopic transclivus approaches represent a useful option in selected cases of anterior midline foramen magnum meningiomas, to be performed in centers with advanced experience in endoscopic skull base surgery, with the caveats of increased risk of postoperative cerebrospinal fluid leak. Alternatively, radiosurgery remains an option for well-selected cases, especially for the management of asymptomatic patients with small enlarging tumors. Advances in molecular profiling, as well as genetic analysis, may guide adjuvant treatment.

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Resumen Los meningiomas son tumores del sistema nervioso central que representan alrededor del 14,3% a 19%, de ellos solo un 1.8% a 3,2% surge en el foramen magno, por años el abordaje de esta clase de tumores conllevaba una gran morbimortalidad asociada debido a que el foramen magno contiene una serie de estructuras anatómicas y neurovasculares críticas, sin embargo con el progreso de las técnicas quirúrgicas, el manejo de la anestesia neurológica y la formación de neurocirujanos con experiencia en cirugías de base de cráneo, ha podido revertir estos resultados y hacer de la cirugía una alternativa segura con bajas tasas de complicaciones. El presente trabajo pretende revisar la literatura acerca de la morbimortalidad asociada a los meningiomas de foramen magno y presentar un caso abordado en nuestro centro.

The meningiomas are tumors of the central nervous system that represent around 14.3% to 19%, of them only 1.8% to 3.2% arise in the foramen magnum, for years the approach of this class of tumors entailed a great associated morbidity and mortality because the foramen magnum contains a series of critical anatomical and neurovascular structures, however with the progress of surgical techniques, the management of neurological anesthesia and the training of neurosurgeons with experience in skull base surgeries, it has been able to reverse these results and make surgery a safe alternative with low complication rates. The present work aims to review the literature about morbidity and mortality associated with meningiomas of foramen magnum and present a case addressed in our center.

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We present the case of a meningioma of the foramen magnum, in a patient of age 62 yr, who presented at the time of surgery a hemiparesis on the right side at 2 mo of evolution. The patient gave his informed consent for the publication of the case, and approval was obtained from the research department of the hospital where the procedure was performed. The magnetic resonance imaging (MRI) in the mid-sagittal view shows a meningioma of the foramen magnum, with an extension in the posterior fossa and in the upper part of the cervical canal. In the coronal view and in the axial view, we can identify that although it is a meningioma of the anterior part of the foramen magnum, it is observed that the lesion has a displacement towards the right side. In a cadaveric specimen, we show the normal anatomy and the key landmarks for performing the approach. The patient was treated by a far lateral approach with a partial removal of the condyle. We show the craniectomy and the microsurgical technique for the tumor resection step by step. We paid particular attention in the anatomy surrounding the tumor and the tips and tricks for a safe resection. We reached a total resection with a good outcome; the result of the anatomopathological study confirmed the diagnosis of meningothelial meningioma. The dura was closed in a hermetic manner with a synthetic dura patch; then sealant was placed. The bone defect was corrected by placing a mesh in titanium. Then the flap was closed as usual. The patient has a good evolution with 1 yr of follow-up and without lesion in the control MRI.

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Introduction Intracranial dermoid tumors represent a rare clinical entity that accounts for 0.04 to 0.6% of all intracranial tumors. Their location in the posterior fossa is uncommon. Objectives To report the case of a young woman with a posterior fossa dermoid cyst treated by right far lateral approach. Case Report A 17-year-old woman presenting with swallowing difficulties for 6 weeks was referred for a neurological investigation. Amagnetic resonance imaging (MRI) scan showed a hyperintense T1-weighted large expansive lesion occupying the posterior fossa and compressing the anterior face of the brain stem and cerebellum. The patient underwent surgical treatment by right far lateral approach with decompression of vascular and neural structures. The patient presented an uneventful recovery, and was discharged home on the fourth postoperative day without any additional neurological deficits. The anatomopathological analysis confirmed the diagnosis of dermoid cyst. Conclusion The far lateral approach is a safe and feasible route to appropriately treat large posterior fossa dermoid cysts. Decompression of vascular and neural structures is essential to achieve good symptom control.

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Foramen magnum meningiomas cause different symptoms based on the size and the location of the tumor. They often present with involvement of the long tracts and of the lower cranial nerves.Ataxia and occipitocervical headache are other common symptoms. In the present study, we report a case of foramen magnum meningioma presenting with cough syncope. A mass lesion located anterolateral to the foramenmagnumwas detected in a 38-year-oldmanduring amagnetic resonance imaging (MRI) exam; the lesion extended from the inferior clivus to the level of the C2 vertebra. The neural axis has pushed towards posterior and contralateral side by the mass. We think that syncope occurred due to the encasement of the vertebral arteries by the tumor in addition to the compression of the neural axis. The posterolateral approach without condylar resection provides a safe surgical plane for total excision of these tumors. In our case, the tumor was totally removed and the syncope episodes were resolved.

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This anatomical study was performed to elucidate the pertinent foraminal and lateral L5 nerve anatomy to enhance our understanding of possible neurologic causes of failed decompression surgery. Persistent extraforaminal L5 nerve compression is a possible cause of persistent symptoms following lumbosacral surgery. The amount of extraforaminal space for the L5 ventral ramus was examined in fifty adult human skeletons (100 sides). Based on morphology, the specimens were then categorized (types I-IV) on the basis of the bony space available for the nerve at this location. Next, 25 embalmed adult cadavers (50 sides) underwent bilateral dissection of the lower lateral lumbar region. The type of bony extraforaminal outlet was documented for each cadaver on the basis of our skeletal analysis. Lastly, segments (intra- and extra-foraminal) of the L5 ventral ramus were excised and examined histologically. Types I-IV outlets were found in 43, 31, 20 and 6 skeletal sides, respectively. For cadavers, 22,15, 10 and 3 sides were found to have types I-IV bony outlets, respectively. In cadavers, all type IV outlets and 70% of the type III bony configurations adjacent to the L5 ventral ramus had signs of neural irritation/injury including vascular hyalinization and increased fibrosis distal to the intervertebral foramen. No distal segments of type I and type II outlets showed histological signs of neural compromise. Patients with symptoms referable to L5 nerve compression for whom no proximal pathology is identified could warrant investigation of the more distal extraforaminal segment of this nerve.

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This article intends to describe in a didactical and practical manner the suboccipital far-lateral craniotomy. This is then basically a descriptive text, divided according to the main stages involved in this procedure, and that describes with details how the authors currently perform this craniotomy.

O presente artigo visa descrever de forma didática e prática a realização da craniotomia suboccipital extremo-lateral. Trata-se, portanto, de um texto fundamentalmente descritivo, dividido conforme as principais etapas da realização dessa craniotomia, e que descreve com detalhes a técnica com que o presente grupo de autores evolutivamente veio a realizá-la.

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