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The oculomotor triangle is denoted as the \"Triangle of Hakuba\" or the \"Hakuba's Triangle.\" This oculomotor triangle is a significant anatomical landmark. Oculomotor nerve, abducens nerve and part of the internal carotid artery (ICA) lie in this triangle. The determination of this analysis is to calculate the oculomotor triangle in dry processed skull bones of the south Indian population and its clinical significance. Fifty-one processed skulls of human origin were received from Anatomy Department, Basic Medical Sciences, Saveetha Dental College. Length from anterior-clinoid process (ACP) to posterior-clinoid process (PCP), length from PCP to APEX, and length from ACP to APEX were measured. Paired samples t-test was considered to analyze the values between the right triangle with the left triangle. From the measurements taken, the mean for the left side of the oculomotor triangle, ACP to PCP was 8.0591 ± 0.52 mm and the right side was 7.5482 ± 0.52 mm. The mean left side of the oculomotor triangle, measured from PCP to APEX was 6.73 ± 0.48 mm and the right side was 6.55 ± 0.72 mm. The mean of the left side of the oculomotor triangle, measured from ACP to APEX was 15.94 ± 0.682 mm and the right side was 16.21 ± 0.747 mm. Through this paired triangle of the cranial cavity, the horizontal section of ICA may be correlated with numerous vascular-related pathological considerations.

Background: The trochlear nerve is unique in its origin, course, and function, being the longest and thinnest among all cranial nerves, underscores the nerve's vulnerability during surgical procedures. Material and Methods: Thirty-two trochlear nerves from sixteen formalin preserved brains of human cadavers were examined. The course of the trochlear until it reaches the lateral wall of the cavernous sinus. Measurements made from the tentorial entry point to anterior clinoid process and posterior clinoid process, origin of the nerve until tentorium entry point, total tentorial length of the nerve noted. Results: We describe segment under the tent as \"Subtentorial\" segment, being separate from the tentorial segment. Mean distance between trochlear nerve and dural entrance on right and left sides was 28.08 mm and 27.95 mm, respectively. The mean length of tentorial segment was found to be 7.81 mm on the right side and 8.11 mm on the left side. The mean distance from the anterior clinoid process (ACP) to the dural entrance of the trochlear nerve on right side was 17.63 mm and the left side was 18.00 mm. The mean distance from the posterior clinoid process (PCP) to the dural entrance of the trochlear nerve was 12.97 mm on the right side and was 12.50 mm on the left side. Conclusion: The study provides valuable prescience into the cadaveric anatomy of the trochlear nerve's entry into the tentorium emphasizing its application in various skull base surgeries.

BACKGROUND:The sellar wall of the sphenoid sinus and its recesses have been previously studied, but their intracranial relationships to the diaphragma sellae, tuberculum, clinoid segment of the internal carotid artery, chiasmatic sulcus, and middle clinoid process need further definition. OBJECTIVE:To describe these intra- and extracranial relationships of the recesses in the anterior sellar wall. METHODS:The middle clinoid was studied in 132 parasellar areas of dry crania. Thirty-eight parasellar areas of formalin-fixed/silicone-colored specimens were dissected. After transsphenoidal endoscopic exposure, the optic, carotid, and sellar prominences; lateral opticocarotid and tuberculum recesses; and caroticosellar and medial opticocarotid points were identified. High-speed drills opened 1-mm perforations at these points to allow study of intracranial relationships. RESULTS:Two recesses and 2 junction points can be recognized in the sphenoid sinuslateral opticocarotid and tuberculum recesses and medial opticocarotid and caroticosellar points. The lateral opticocarotid recess corresponds to the optic strut base, and the clinoid segment of the internal carotid artery is located medially. The diaphragma sellae attachment is at the level of the tuberculum recess, which in 50% of cases corresponds to the tuberculum. A middle clinoid in base or height greater than 1.5 mm is present in 21.1% and a caroticoclinoid ring in 3%. The middle clinoid is 1 mm inferior and lateral to the caroticosellar point and 4.7 mm inferior to the medial opticocarotid point. CONCLUSION:An understanding of the intra- and extracranial relationships of the recesses of the sphenoid sinus will aid in accurately directing transsphenoidal approaches.

PurposeThe present work aimed to classify the pneumatization of the dorsum sellae (DS) in subjects aged 1–90 years.MethodsThe study consisted of computed tomography images of 1080 subjects (582 males / 498 females), aged 1–90 years (mean age: 45.51 ± 26.06 years). Four different types regarding DS pneumatization were defined as follows: Type 0: no pneumatization, Type 1: pneumatization < 50%, Type 2: pneumatization > 50%, and Type 3: total pneumatization.ResultsDS pneumatization was identified in 354 (32.8%) subjects (189 males and 165 females). Its pneumatization was identified in 51 (21.2%) out of 241 children, and 303 (36.1%) out of 839 adults. The frequency of DS pneumatization types was found as follows: Type 0 (no pneumatization in 726 subjects, 67.2%) > Type 1 (pneumatization < 50% in 234 subjects, 21.6%) > Type 2 (pneumatization > 50% in 87 subjects, 8.1%) > Type 3 (total pneumatization in 33 subjects, 3.1%). DS pneumatization incidence was affected by ages (p < 0.001), but not sex (p = 0.818). The pneumatization degrees of DS (i.e., the distributions of Types 1–3) were not affected by ages (p = 0.637) or sex (p = 0.391).ConclusionThe pneumatization incidence of DS increased significantly with advancing adult ages (especially in elderly people). DS pneumatization should be taken into account by neurosurgeons and neuroradiologists to decrease the risk of complications such as cerebrospinal fluid fistula during surgeries such as posterior clinoidectomy.

The anterior clinoid process (ACP) is a critical anatomical landmark for skull base surgery. Pneumatization of the ACP can affect surgical planning and outcomes. Morphometric evaluation provides essential data for safer interventions. A total of 154 CT images from individuals aged 1-79 years were retrospectively analyzed. ACP pneumatization types (Type 0-3), bilateral height and width, and inter-ACP distance were evaluated. Morphometric values were stratified by age and gender. Among 154 patients, 54.5% were female and 45.5% male. Pneumatization was more common in males, with statistically significant differences observed for both left(p < 0.001) and right (p = 0.021) sides. ACP widths showed a moderate positive correlation with age. Males had wider ACPs, whereas females had greater ACP heights. Logistic regression indicated male gender and younger age as predictors of ACP pneumatization. ACP pneumatization is significantly influenced by gender but not by age. Morphometric differ ences exist between sexes and age groups. Knowledge of these variations is essential for minimizing intraoperative complications during skull base surgeries.

Background The optimal management of clinoidal meningiomas (CMs) continues to be debated. Methods We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of these tumors. The data from the literature along with contemporary practice patterns were discussed within the task force to generate consensual recommendations. Results and conclusion This article represents the consensus opinion of the task force regarding pre-operative evaluations, patient’s counselling, surgical classification, and optimal surgical strategy. Although this analysis yielded only Class B evidence and expert opinions, it should guide practitioners in the management of patients with clinoidal meningiomas and might form the basis for future clinical trials.

Purpose To describe pneumatization and topographic position of the posterior clinoid process (PCP) in healthy children when approaching the anterior and middle fossae. Methods The study consisted of computed tomography images of 180 pediatric patients (90 males / 90 females), aged 1–18 years. The presence or absence of PCP pneumatization was noted, and the distances of certain landmarks to PCP were measured. Results The distances of the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process (ACP), foramen magnum and crista galli to PCP were measured as 18.59 ± 3.36 mm, 15.37 ± 3.45 mm, 14.60 ± 3.05 mm, 5.27 ± 3.24 mm, 32.03 ± 3.27 mm, and 30.45 ± 3.93 mm, respectively. These parameters increased with growth (between 1–18 years), but the distance between PCP and ACP decreased with an irregular pattern. In 11 sides (3.10%), a fusion between PCP and ACP was determined. PCP pneumatization was identified in 32 sides (8.9%). Its pneumatization correlated with pediatric ages ( p  < 0.001), but not gender ( p  = 0.459) or side ( p  = 0.711). Most of PCP pneumatization appeared after late childhood period (i.e., between 10–18 years). Conclusion Our study provides beneficial data for neurosurgeons to use PCP as a reference point for creating a skull base map in children, because of the incomparable position of PCP in the skull base center.

Background Proximal arterial control is critical for safe and effective microsurgical clipping of ophthalmic segment aneurysms (OSAs). Traditionally, this is achieved via neck dissection and temporary clamping of the cervical internal carotid artery (ICA). Advances in endovascular technology have introduced temporary balloon occlusion (TBO) as a potentially less invasive alternative. This study aims to assess the utility of TBO during microsurgical clipping of OSAs. Methods A retrospective review was conducted of all patients at a single institution who underwent microsurgical OSA clipping with planned TBO. Patient demographics, presentation, aneurysm morphology, occlusion outcomes, complications, recurrence, and functional outcomes based on modified Rankin score (mRS) at follow-up were evaluated. Patients who underwent balloon inflation for proximal control (+ TBO) were compared with those who did not (-TBO). Results A total of 34 patients with 35 OSAs were included. A temporary balloon guide catheter was successfully navigated to the cervical carotid in all cases. TBO was performed in 19 patients (20 aneurysms) during aneurysm clipping. Aneurysm sizes ranged from 2.8 to 18.0 mm (mean: 6.7 mm), with neck sizes ranging from 1.6 to 8.1 mm (mean: 4.2 mm). The + TBO group had a significantly higher proportion of wide-necked aneurysms (> 4 mm) compared to the -TBO group (55.0% vs. 26.7%; p = 0.008) and more frequently required anterior clinoidectomy (84.2% vs. 46.7%; p = 0.020). Complete or near-complete (< 2 mm remnant) aneurysm occlusion was achieved in all cases. There was one complication (2.9%) with permanent sequela and median mRS at follow-up was 0. There were no significant differences in complication rates or functional outcomes between the + TBO and -TBO groups. Conclusion Endovascular-assisted TBO is a safe and effective minimally invasive alternative to open neck dissection for achieving proximal control during OSA clipping. TBO may be particularly advantageous for managing wide-neck aneurysms.

Background Extradural anterior clinoidectomy (EAC) and dural peeling of the lateral wall of the cavernous sinus (CS) are challenging skull base techniques that enhance exposure to anterior and middle cranial fossa lesions. Intimate knowledge of dural anatomy enables safe dissection and identification of critical neurovascular structures without cranial nerve deficit postoperatively. Methods In a patient with a middle/inner ridge sphenoid wing meningioma, EAC and targeted dural peeling allowed for a Simpson grade I resection. Conclusion EAC and targeted dural peeling enable a feasible Simpson grade I resection of a middle/inner ridge sphenoid wing meningioma, while minimizing neurovascular injury.

Background Tumours of the parasellar area may engulf the internal carotid artery(ICA) and its branches which may preclude complete resection and may be a risk factor for ischemic complications. Methods We present a surgical technique based on a stepwise identification of the arterial branches which may enable a complete resection in selected cases even when complete encasement of the ICA is present on preoperative images. Conclusion Resection of tumours encasing the major vascular structures should be systematically attempted while continuously weighing the delicate balance between the risk of vascular injury and the extent of resection.