Hydrocephalus caused by unilateral foramen of Monro (FM) obstruction has been referred to in literature by many different terminologies. Precise terminology describing hydrocephalus confined to just one lateral ventricle has a very important prognostic value and determines whether or not the patient can be shunt free after an endoscopic procedure. Aiming to define the best term for unilateral FM obstruction, 19 terms were employed on PubMed database (http://www.ncbi.nlm.nih.gov/pubmed) as quoted phrases. A total of 194 articles were found. Four patterns of hydrocephalus were discriminated as a result of our research term query and were divided by types for didactic purpose. Type A - partial dilation of the lateral ventricle; Type B - pure unilateral obstruction of the FM; Type C - previously shunted patients with secondary obstruction of the FM; and Type D - asymmetric lateral ventricles with patent FM. In unilateral FM obstruction hydrocephalus, an in-depth review on terminology application is critical to avoid mistakes that may compromise comparisons among different series. This terminology review suggests that Type B hydrocephalus, i.e., the hydrocephalus confined to just one lateral ventricle with no other sites of cerebrospinal fluid circulation blockage, are best described by the terms unilateral hydrocephalus (UH) and monoventricular hydrocephalus, the first being by far the most popular. Type A hydrocephalus is best represented in the literature by the terms uniloculated hydrocephalus and loculated ventricle; Type C hydrocephalus by the terms isolated lateral ventricle and isolated UH; and Type D hydrocephalus by the term asymmetric hydrocephalus.

Background: Cavum septum pellucidum (CSP) and cavum vergae (CV) are normal anatomical variations present in some children, adolescents, and adults. When the cavity is larger than normal, it is called a cyst. Symptomatic cases of CSP and CV cyst are rare, and the clinical presentation is varied. A case with multiple nerve involvement is described. Case Description: A healthy 17-year-old female presented a sudden headache, right cervicobrachialgia, right ptosis, visual changes, and left facial paralysis over 10 days. Head magnetic resonance imaging revealed CSP and CV cyst. Inflammation, infection, and vascular disorders were ruled out. We decided to perform a right transfrontal endoscopic intraventricular septostomy and a right Monro foraminoplasty, which were successful. One month after surgery, the patient had no more signs or symptoms. She has remained asymptomatic for the past year. Conclusion: Multiple nerve involvement was directly related to CSP and CV cyst. The cyst bilaterally occluded the foramen of Monro causing intracranial hypertension. It was possible to obtain complete resolution of the clinical features through neuroendoscopic fenestration and foraminoplasty.

Ventricular tumors represent a major neurosurgical challenge, making endoscopic approach an invaluable tool as it gained importance due to technological advances. Nevertheless, the method is not exempt of risk and limitations, sometimes requiring an open surgery. Thus, initial measurements must be adopted in order to simplify an eventual need for conversion to open craniotomy. Here, we describe a series of 6 patients with ventricular tumors approached by neuroendoscopy where the conversion to microsurgery turned out to be necessary. Patients' average age was 59.5 years (39-75 years). Average tumoral size was 17.8 mm (15-21 mm). There were 2 cases of lateral ventricle subependymoma and 4 cases of third ventricle colloid cysts. A standard surgical incision was performed in the coronal direction, allowing lateral expansion to 10 cm. Moreover, the endoscopic burr hole was enlarged to a 5 cm craniotomy. A small enlargement of the endoscopic cortical access was performed to gain a transcortical microsurgical corridor to the ventricular cavity. The need for conversion arose due to high consistency of the tumor (3 cases), technical problems (2 cases), and cortical collapse (1 case). There was one case of cerebrospinal fluid fistula and infection and one case of transitory memory disturbance. In both the cases, we obtained a complete functional recovery. Clinical and radiological follow-up showed total tumor removal with no recurrences. The technique herein described was easy to perform, promptly bypassed the endoscopic limitations, and gathered excellent surgical results. The possibility of adapting the method to other tumor locations may be considered.

Background: Gangliogliomas are rare tumors of the central nervous system. They are usually located intracranially and rarely in the spinal cord. There is no clear correlation between this tumor and neurofibromatosis type 1 (NF1) with only four cases described. The aim of this article is to describe one more case and add data to the literature regarding this rare association. Case Description: An 8-year-old boy with NF1 presented progressive asymmetrical paraparesis (Grade 4 medical research council scale on the right leg and Grade 3 on the left leg). The cervicothoracic spinal magnetic resonance imaging demonstrated an intramedullary lesion from C4 to T4 vertebrae. The patient underwent a microsurgical resection. A partial resection was performed due to a drop in the motor evoked potential signal amplitude during dissection. Pathology report revealed a ganglioglioma (World Health Organization Grade I). Postoperatively, the patient evolved with worsening of the paraparesis. A few weeks later, he has improved his preoperative functional neurological state (better strength and gait). Adjuvant radiotherapy was not used. The patient is being followed up at the neurosurgery outpatient clinic. Conclusion: This is another case of spinal ganglioglioma associated with NF1. The tumor must be included in the differential diagnosis of patients with NF1 and spinal lesions. Complete microsurgical resection remains the standard treatment for spinal gangliogliomas, however, in this specific case, it was decided to leave a portion of the tumor to prevent neurological damage. The prognosis and treatment of this condition associated with NF1 remains to be determined.

Background: Navigated transcranial magnetic stimulation (nTMS) is a well establish a noninvasive method for preoperative brain motor mapping. We commonly use magnetic resonance imaging (MRI) to supply the nTMS system. In some cases, MRI is not possible or available, and the use of computed tomography (CT) is necessary. We present the first report describing the association of CT and nTMS motor mapping for brain lesion resection. Case Description: CT imaging of a 59-year-old man suffering from acquired immune deficiency syndrome for 17 years, presenting with seizure and right hemiparesis, revealed a small single hypodense ring-enhancing lesion in the left central sulci suggesting cerebral toxoplasmosis. After 3 weeks of neurotoxoplasmosis treatment, due to four consecutive tonic-clonic seizures, a new CT scan was performed and showed no lesion changes. MRI was in maintenance at that time. Infectious diseases department suggested a brain lesion biopsy. Due to lesion’s location, we decided to perform a presurgical nTMS motor mapping. After a small craniotomy, we could precisely locate and safely totally remove the lesion. The pathology report revealed a high suspicious toxoplasmosis pattern. The patient was discharged after 2 days and continued toxoplasmosis treatment. After 6 months follow-up, he showed no signs of any procedure-related deficits or radiological recurrence. Conclusion: We report the feasibility and applicability of nTMS motor mapping using CT scan as an image source. It gives neurosurgeons another possibility to perform motor mapping for brain lesion removal, especially when MRI is not available or feasible.

Background: Spinal dural arteriovenous fistula (SDAVF) is the most frequent vascular malformation of the spine and accounts for approximately 70% of all vascular spinal malformations. In rare cases, SDAVF rupture and subsequent subarachnoid hemorrhage or intramedullary hematoma may occur. The aim of this article is to present a fatal case of SDAVF rupture after a Rathke’s cleft cyst (RCC) endoscopic resection. Case Description: An 80-year-old female was referred to our hospital with a clinical presentation of bilateral reduction in visual acuity, bitemporal hemianopsia, and sellar magnetic resonance imaging (MRI) highly suggestive of RCC. After the first endonasal endoscopic surgery, the cyst was partially removed and vision improved. No signs of cerebrospinal fluid (CSF) leak were observed. After 1 year, the patient returned because of RCC recurrence and decreased visual acuity. In the second procedure, the lesion was totally resected and CSF leak was observed. A nasoseptal flap was rotated to cover the skull base defect. The patient developed subtle paraparesis followed by paraplegia on the 4th postoperative day. The dorsal spine MRI revealed a T3-T4 intramedullary hematoma. A dorsal laminectomy was performed and a SDAVF was observed. During microsurgery, at the right T3 nerve root level, an arteriovenous shunting point was identified, coagulated, and divided. The intramedullary hematoma was evacuated. The patient developed neurogenic and septic shock and died. Conclusion: Venous hypertension, venous wall fragility, and venous thrombosis seem to be the main factors involved in SDAVF rupture. In this particular case, reduction of the extravascular pressure and sudden variation in the pressure gradient caused by sustained CSF leak, also appeared to play an important role in SDAVF rupture. It may represent one more complication related to radical resection of RCC.