Previous studies have indicated that amputation or deafferentation of a limb induces functional changes in sensory (S1) and motor (M1) cortices, related to phantom limb pain. However, the extent of cortical reorganization after lower limb amputation in patients with nonpainful phantom phenomena remains uncertain. In this study, we combined functional magnetic resonance (fMRI) and diffusion tensor imaging (DTI) to investigate the existence and extent of cortical and callosal plasticity in these subjects. Nine "painless" patients with lower limb amputation and nine control subjects (sex-and age-matched) underwent a 3-T MRI protocol, including fMRI with somatosensory stimulation. In amputees, we observed an expansion of activation maps of the stump in S1 and M1 of the deafferented hemisphere, spreading to neighboring regions that represent the trunk and upper limbs. We also observed that tactile stimulation of the intact foot in amputees induced a greater activation of ipsilateral S1, when compared with controls. These results demonstrate a functional remapping of S1 in lower limb amputees. However, in contrast to previous studies, these neuroplastic changes do not appear to be dependent on phantom pain but do also occur in those who reported only the presence of phantom sensation without pain. In addition, our findings indicate that amputation of a limb also induces changes in the cortical representation of the intact limb. Finally, DTI analysis showed structural changes in the corpus callosum of amputees, compatible with the hypothesis that phantom sensations may depend on inhibitory release in the sensorimotor cortex.

Amputation in adults is associated with an extensive remapping of cortical topography in primary and secondary sensorimotor areas. Here, we used tactile residual limb stimulation and 3T functional magnetic resonance imaging in humans to investigate functional connectivity changes in the sensorimotor network of patients with long-term lower limb traumatic amputations with phantom sensation, but without pain. We found a pronounced reduction of inter-hemispheric functional connectivity between homologous sensorimotor cortical regions in amputees, including the primary (S1) and secondary (S2) somatosensory areas, and primary (M1) and secondary (M2) motor areas. We additionally observed an intra-hemispheric increased functional connectivity between primary and secondary somatosensory regions, and between the primary and premotor areas, contralateral to amputation. These functional connectivity changes in specialized small-scale sensory-motor networks improve our understanding of the functional impact of lower limb amputation in the brain. Our findings in a selective group of patients with phantom limb sensations, but without pain suggest that disinhibition of neural inputs following traumatic limb amputation disrupts sensorimotor topology, unbalancing functional brain network organization. These findings step up the description of brain plasticity related with phantom sensations by showing that pain is not critical for sensorimotor network changes after peripheral injury.

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.

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Background: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.Methods: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.Results: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.Conclusion: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.

We report two cases of complex middle cerebral artery aneurysms that were surgically treated using the orbitopterional approach in a two-piece method. The objective of this work is to discuss the usefulness of the orbitopterional approach in the surgical management of large and giant middle cerebral artery aneurysms. A 32-year-old man with a giant aneurysm and a 50-year-old woman with a large and complex aneurysm presented with subarachnoid hemorrhages. Both aneurysms were successfully clipped through an orbitopterional approach. This approach permits a more basal view of the vascular structures with only a minor retraction of frontal lobe. It also increases the view angle and amount of working space available. This approach should be considered as an alternative to the classic pterional craniotomy for the surgical management of such complex lesions.

Microsurgery remains the gold standard treatment for intraventricular lesions, but it is not without limitations. The cerebral ventricles approach is considered a challenge for neurosurgeons because of their deep location and their intimate association with critical areas of the brain. It has been shown that direct endoscopic view is superior to magnetic resonance imaging (MRI) in identifying intraventricular structures and lesions. Also, during neuroendoscopy, there is no cerebrospinal fluid leak causing brain collapse as seen in microsurgery. Different surgical strategies should be shared and may improve and facilitate intraventricular lesions resection. Herein, a case of a successful microsurgical cavernoma resection with prior ventriculoscopy is described. A 28-year-old woman was admitted with intense holocranial headache. A mild stiff neck was observed. MRI showed a 3-cm lesion with heterogeneous signal intensity and no contrast enhancement suggestive of cavernoma. Initially, a ventriculoscopy was done to inspect the lesion and the surrounding ventricular structures. After that, a conversion technique from endoscopy to microsurgery was performed. The initial corticectomy was extended and the endoscope pathway was followed into the ventricular cavity. Then, the cavernoma was completely removed by microsurgical technique. No complications were observed. Control MRI showed total tumour removal. The patient remained asymptomatic with no recurrence after 1 year. This case illustrates a successful prior endoscopic approach followed by microsurgery as an alternative to a direct microsurgical approach for intraventricular cavernoma. A previous direct endoscopic view of the lesion and its relation with intraventricular structures may ensure a safe and complete resection by microsurgery.

Background: Endoscopic endonasal transsphenoidal approach (EETA) is a well-established technique for sellar tumor resection. However, this route causes aerosol dispersion from the nasal cavity. In the context of the coronavirus (COVID-19) pandemic, new measures were taken aiming at the safety and protection of patients and health-care professionals. Herein, we present a Brazilian experience with EETA during COVID-19 pandemic. Methods: This study was based on the review of medical records and observation in the operating room of the patients undergoing endoscopic surgery in the period from May 2020 to July 2022. All patients were tested by real-time polymerase chain reaction (RT-PCR) COVID-19 before and after surgery. Since September 2021, it has been mandatory to present vaccination cards for adults (over 18 years old). Results: This case series included 28 patients and 35 surgical procedures using the EETA, who presented of nonfunctioning macroadenomas (19 cases − 67.8%), GH-secreting tumor (three cases − 10.8%), ACTH-secreting tumor (three cases − 10.8%), meningiomas (two cases − 7.1%), and Rathke’s cleft cyst (one case – 3.5%). There were eight cases of diabetes insipidus (28.5%), five cases of cerebrospinal fluid leak (17.8%), and one case of meningitis (3.5%). Three patients died due to meningitis (one case), carotid occlusion (one case), and COVID-19 complications (one case). Conclusion: A simple protocol was established to perform EETA during the COVID-19 pandemic. The pituitary surgeries were maintained to treat critical cases. To date, the protocol should be continually updated to improve the procedure’s safety.