The Technique for Transorbital Ventricular Puncture: An Anatomic Approach.

BACKGROUND AND OBJECTIVES: Transorbital ventricular puncture is a minimally invasive described procedure with poor landmarks and anatomic references. This approach can be easily performed to save patients with intracranial hypertension, especially when it is secondary to an acute decompensated hydrocephalus. This study aims to describe anatomic structures and landmarks to facilitate the execution of transorbital puncture in emergency cases. METHODS: We analyzed 120 head computed tomographies to show the best area to perform the procedure in the orbital roof. Two adult cadavers (4 sides) were punctured in the predetermined area. Angles, distances, landmarks, and anatomic structures were registered. This approach to the ventricular system may be performed at bedside to relieve intracranial hypertension only in specific cases. RESULTS: The perforation point is 2.5 cm (female) or 3.0 cm (male) lateral to the midline and immediately inferior to the superciliary arch. A vertical line, parallel to midline, was drawn on the outer edge of the patient's forehead, the needle was 45° inferiorly and 20° medially and then progressed 2.0 cm backwards to reach the bone perforation point. After that, it was advanced another 4.5cm approximately until it reached the anterior horn of the lateral ventricle. CONCLUSION: Based on statistical and experimental evidences, we were able to establish reliable anatomic reference points to access the anterior horn of the lateral ventricle through transorbital puncture.

Middle fossa triangles - A step-by-step dissection.

Background: The anatomy and surgical approach to the cavernous sinus and the middle fossa can constitute a considerable challenge, specially for young surgeons. Although their surgical explorations have gone through a popular phase in the past, to this date, they remain an uncomfortable subject for many neurosurgeons. The aim of this paper is to systematically review its anatomy and multiple corridors through a step-by-step dissection of the middle fossa triangles, providing a roadmap for surgeons. Methods: A step-by-step dissection of the cavernous sinus was performed in two fresh-frozen cadavers aiming to describe the anatomy of ten different middle fossa triangles, demonstrating the feasibility of the use of their spaces while surgically approaching this area. Results: The intradural opening of the roof of the cavernous sinus was obtained by dissection of clinoidal, carotid-oculomotor, supratrochlear, optic-carotideal, and oculomotor triangles, allowing an expanded superior view. On the counterpart, the extradural exploration of the lateral wall through the middle fossa floor peeling exposed the infratrochlear, anteromedial, and anterolateral triangles. The middle fossa floor itself was the door to approaching posterior fossa through anterior petrosectomy. The dissection of each individual triangle can be amplified exponentially with exploration of its adjacents, providing broader surgical corridors. Conclusion: The cavernous sinus still remains far from an "every man's land," but its systematic study based on direct approaches can ease the challenges of its surgical exploration, allowing surgeons to feel more comfortable with its navigation, with consequently benefit in the treatment of patients.

Diffuse spinal cord metastasis after resection of SMARCB1 sinonasal carcinoma manifesting with a right foot drop-a case report.

INTRODUCTION: The sinonasal carcinoma are rare tumors of the head and neck. The undifferentiated sinonasal carcinoma subtypes are constantly being explored and new mutations, with different prognosis markers and biological behaviors are being described. The SMARCB1 negative sinonasal carcinoma subtypes have been recently described with few reports of leptomeningeal and spinal cord invasion. CASE PRESENTATION: This study presents the case of a 59-year-old woman, with no previous disease, presenting initially with epistaxis that evolved to cranial nerve deficits and a left eye complete oftalmoplegia. After diagnostic investigation, she had a diagnosis of a left ethmoid sinus sinonasal carcinoma. Following resection of the tumor, she evolved with a right foot drop that eventually has been linked to diffuse spinal cord impairment. The histopathological diagnosis confirmed a SMARCB1 negative sinonasal carcinoma. Due to the diffuse metastasis, she underwent palliative care and died eight months after the surgery. DISCUSSION: Spinal cord metastasis may manifest with different clinical signs. Our case shows a rare manifestation of SMARCB1-deficient sinonasal carcinoma, a new subtype of sinonasal carcinoma, summarizing the importance of a high grade of suspicion of spinal cord invasion on these patients. SMARCB1 sinonasal carcinomas are rare new tumors of the head and neck, whose biological behaviors are yet to be explored. To the best of our knowledge, this is one of the few case reports describing simultaneous spread of this tumor to the central nervous system and spinal cord.

Brain cryptococcoma mimicking a glioblastoma in an immunocompetent patient: A rare case report and comprehensive review.

Background: Cryptococcosis is an invasive fungal infection primarily affecting lungs and potentially spreading to the central nervous. This fungal infection might be misdiagnosed as other infection diseases, such as tuberculosis; granulomatous diseases, like sarcoidosis; and even neoplastic diseases. Some previous reports described cases of cryptococcomas resembling brain tumors. In this paper, we present a very rare presentation of brain cryptococcoma mimicking a malignant glioma. To the best of our knowledge, this is the third case description in the literature. Case Description: A 64-year-old male patient presented at the hospital with a history of progressive frontal headache for 1 month, becoming moderate to severe, associated with visual changes, without nausea or vomiting. No fever was reported. He was a heavy smoker and denied other relevant previous medical data. Neuroimage disclosed a right temporal expansive lesion initially considered a malignant glioma. The patient underwent a right temporal craniotomy and biopsy revealed a cryptococcoma. Conclusion: Cryptococcomas characteristics in magnetic resonance are quite nonspecific. They should always be included in differential diagnosis of expansive brain lesions, both malignant and benign. Therefore, once cryptococcomas may resemble like other intracranial expansive lesions, biopsy should always be carried out to clarify diagnosis and avoid inadequate treatment and definition of prognosis only based on radiological patterns.

Cerebellar mutism following head trauma: A case report and literature review.

BACKGROUND: Cerebellar mutism (CM) is defined as the lack of speech production, despite an intact state of consciousness and cognitive function, that happens secondary to a cerebellar insult. To the best of our knowledge, only five cases have thus far been described in the English literature. In this paper, we report the sixth incidence overall, which is also the first case of a CM associated with penetrating head injury. The relevant literature is reviewed and analyzed, our current knowledge of the neuroanatomical and functional relations is summarized, and potential future research endeavors are indicated. CASE DESCRIPTION: An 8-year-old girl was transferred to our hospital having had fallen on a rod that penetrated her neck behind the ear. An urgent computed tomography scan of the head revealed a right cerebellar contusion with surrounding edema. Three days later, she became mute but was still obeying commands. Repeat imaging showed a resolving cerebellar contusion with increased edema and mass effect. By day 9, she had uttered a few words. At 1-month follow-up, the child had regained normal speech. CONCLUSION: Posttraumatic CM is a rare and probably underreported condition with only six documented cases to date. Although it may well be on the same spectrum as postoperative CM, further understanding of the exact mechanism, clinical course, and prognosis of this entity is bound to significantly improve the recovery and quality of life of head trauma patients.

Postmortem Dissections of the Papez Circuit and Nonmotor Targets for Functional Neurosurgery.

BACKGROUND: The Papez circuit was first described as the anatomic basis of emotion. Subsequent studies consolidated recognition of its limbic activities but showed a more important role in memory. Anatomic dissections and advanced neuroimaging have deepened our understanding of the various interconnections and white matter tracts present in this circuit. The aim of our study is to describe the anatomy of the Papez circuit through cadaveric dissection with correlation to ultrahigh-field magnetic resonance imaging (MRI) and MRI tractography. METHODS: White fiber dissection was performed on 5 cadaveric human brain hemispheres. The Papez circuit was dissected mediolaterally to show its anatomy and relation to other nuclei and tracts. Open-source MRI tractography data from the Human Connectome Project is combined with ultrahigh resolution, 7T structural MRI, and 17.6T diffusion tractography to further show the anatomy. RESULTS: The network connecting the anterior and posterior cingulate, entorhinal cortex, hippocampus, fimbria, dentate gyrus, fornix, mammillary bodies, and anterior thalamus was described using white matter fiber dissection and compared with MRI tractography and ultrahigh-field structural and diffusion MRI. We showed for the first time (through portmortem dissection) fibers directly connecting the anterior thalamic nucleus and the subgenual cingulate via the septal area. CONCLUSIONS: The description of the anatomy of the Papez circuit through cadaveric dissection and comparisons with advanced neuroimaging studies allow a better understanding of its three-dimensional spatial layout, in addition to showing new areas of connectivity with adjacent structures and possibilities for surgical approaches or stimulation.

Comparison Between Transcortical and Interhemispheric Approaches to the Atrium of Lateral Ventricle Using Combined White Matter Fiber Dissections and Magnetic Resonance Tractography.

OBJECTIVE: The objective of this study was to compare transcortical and posterior interhemispheric approaches to the atrium using a combined approach of white matter fiber dissections and magnetic resonance (MR) tractography. METHODS: Ten cerebral hemispheres were examined and dissected from the lateral-to-medial surface and from the medial-to-lateral surface, with special attention to the white matter tracts related to the atrium. MR tractography was used to show the relationship of three-dimensional white matter fibers with the atrium of the lateral ventricle and to compare with cadaveric dissection results. RESULTS: The atrium was related laterally to the superior longitudinal fasciculus II and III, middle longitudinal fasciculus, arcuate fasciculus, vertical occipital fasciculus, and sagittal stratum. Medially, it is related to the superior longitudinal fasciculus I, cingulum, sledge runner, and forceps major. CONCLUSIONS: A combined approach of cadaveric white matter fiber dissections and MR tractography were used to describe the main white matter tracts related to the posterior interhemispheric approach and the transcortical approach, providing an in-depth understanding of the three-dimensional anatomy of white matter fibers and the atrium. In the present study, among approaches examined, the posterior interhemispheric parasplenial transprecuneus approach placed fewer eloquent tracts at risk; however, traversing the sledge runner and the forceps major is unavoidable by this approach.