Tracheal metallic hybrid stent removal via tracheostomy: an unconventional approach.

Increasing use of tracheal expandable metallic hybrid stents will lead to common encounters with these devices in emergency airway management. The presence of these stents qualifies any patient as a challenge when an emergency tracheostomy is needed. We report an unorthodox technique of tracheostomy with concomitant removal of tracheal stent, without any major complications. Although the combined approach with bronchoscopy and tracheostomy has been reported in similar cases, we present a safe procedure when rigid bronchoscopy is not available.

Stereotactic anatomy of the third ventricle.

PURPOSE: Endoscopic third ventriculostomy (ETV) is a surgical procedure that can lead to complications and requires detailed preoperative planning. This study aimed to provide a more accurate understanding of the anatomy of the third ventricle and the location of important structures to improve the safety and success of ETV. METHODS: We measured the stereotactic coordinates of six points of interest relative to a predefined stereotactic reference point in 23 cadaver brain hemi-sections, 200 normal brain magnetic resonance imaging (MRI) scans, and 24 hydrocephalic brain MRI scans. The measurements were statistically analyzed, and comparisons were made. RESULTS: We found some statistically significant differences between genders in MRIs from healthy subjects. We also found statistically significant differences between MRIs from healthy subjects and both cadaver brains and MRIs with hydrocephalus, though their magnitude is very small and not clinically relevant. Some stereotactic points were more posteriorly and inferiorly located in cadaver brains, particularly the infundibular recess and the basilar artery. It was found that all stereotactic points studied were more posteriorly located in brains with hydrocephalus. CONCLUSION: The study describes periventricular structures in cadaver brains and MRI scans from healthy and hydrocephalic subjects, which can guide neurosurgeons in planning surgical approaches to the third ventricle. Overall, the study contributes to understanding ETV and provides insights for improving its safety and efficacy. The findings also support that practicing on cadaveric brains can still provide valuable information and is valid for study and training of neurosurgeons unfamiliar with the ETV technique.

Neurosurgical anatomy of the insular cortex.

OBJECTIVE: The purpose of this study was to clarify the morphology of the insular cortex focusing not only on the shape of the insula, but also on sulcal and gyral organization. PATIENTS AND METHODS: Sixty formalin-fixed adult brain hemispheres had their insula exposed and photographed. The dimensions of each gyrus and sulcus were measured using an image analysis software. The morphometric data obtained was statistically analysed. RESULTS: The insular cortex shape alternates between triangular and trapezoid, being the triangular shape the most common (75%). The angle between the posterior and inferior peri-insular sulcus in the trapezoid insulae had a mean range of 131.17° (SD = 12.277). A minimum of 3 and a maximum of 6 insular gyri were observed, being 5 the most common total number of gyri observed. The accessory gyrus was present in 66% of the insulae and well-developed in 38% of the cases. A statistical association between the number of gyri in the posterior lobe and the presence of a novel gyrus or a more developed accessory gyrus in the anterior lobe was found (P = 0.006). The posterior short gyrus was the longest of the short gyri (P <  0.001), followed by the anterior short gyrus (P < 0.001). The anterior long gyrus was the largest of the long gyri (P = 0.003). The contribution of each of the short gyri to the formation of the insular apex was inconstant. The most common observed apex arrangement was the combination of the anterior and of the middle short gyri. CONCLUSIONS: This study makes a strong contribution to the understanding of the insular cortex anatomy, allowing neurosurgeons to be more capable to decide the best approach to this cortical area.

Morphology and Navigational Landmarks of the Cranio-orbital Foramen in a Portuguese Population.

PURPOSE: The cranio-orbital and accessory foramina are located in the lateral wall of the orbit and adjacent to the superior orbital fissure. In the literature, there is a lack of consistency concerning the location and morphology of these foramina in different populations. Therefore, considering its clinical importance during orbital surgeries, it was the authors' aim to determine the incidence, location, and number of cranio-orbital and accessory foramina in a Portuguese population and compare the findings with data from other studies. METHODS: A total of 310 orbits from 155 dry skulls from the collection of the Museum of Anatomy of the Faculty of Medicine of Porto were studied. The characterization of both cranio-orbital and accessory cranio-orbital foramina was performed. RESULTS: The cranio-orbital foramen was present in at least 1 orbit per skull in 58.17% with a median diameter of 0.60 ± 0.33 mm. No relation was found between the presence of this foramen and the gender of the individuals or a tendency for laterality. However, it was found that the presence of 1 or more accessory foramina was related to higher diameters of the cranio-orbital foramen. CONCLUSIONS: There might be a relationship between the localization, diameter, and communication of foramina with the cranial fossae. Foramina located on the greater wing of the sphenoid bone presented a larger diameter and communicated with the middle cranial fossa. High diameters of the main vessel in the cranio-orbital foramen may imply more developed branches and collateral irrigation of the orbital structures using 1 or more accessory foramina. Surgeons should be aware of the location of the cranio-orbital foramen to reduce potential sources of hemorrhage during orbital dissections.

Neurosurgical relevance of the dissection of the diencephalic white matter tracts using the Klingler technique.

OBJECTIVE: The Klingler fiber dissection technique is a relevant and reliable method for neurosurgery to identify with accuracy the fine structure of the brain anatomy highlighting white matter tracts. In order to demonstrate the significance of the application of this technique, we aimed to observe the course and relations of the mammillothalamic and habenulo-interpeduncular tracts as there are very few papers showing these important diencephalic tracts. MATERIAL AND METHODS: Twelve formalin-fixed brains were dissected using the Klingler technique in order to expose the medial diencephalic surface. Diencephalic white matter tracts, particularly the mammillothalamic and habenulo-interpeduncular tracts, were dissected using wooden spatulas and metallic dissectors with different sizes and tips. Several measurements were performed in both dissected hemispheres relative to the mammillothalamic and habenulo-interpeduncular tracts. RESULTS: The course and length of these two tracts were visualized and the relations with other fiber systems and with the neighboring gray matter structures quantified and registered. The mammillothalamic tract approximately marks the anteroposterior coordinate of the anterior pole of the subthalamic nucleus in the anterior commissure - posterior commissure plane. CONCLUSION: The present study helps to understand the three-dimensional architecture of the white matter systems of tracts when the Klingler technique is used. The numerical data obtained may be helpful to neurosurgeons while approaching brain paraventricular and ventricular lesions and deep brain stimulation. Finally, the anatomical knowledge can lower surgical complications and improve patient care particularly in the field of neurosurgery.