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Background: The tumor invasion of the skull base structures is very frequent in spheno-orbital meningiomas. The aim of the present study is to evaluate the invasion rate of skull base structures and the best surgical approach and management. Methods: The surgical series of 80 spheno-orbital meningiomas was reviewed. The tumors were classified according to the intraorbital location with respect to the optic nerve axes into three types: I-lateral: II-medial; III-diffuse. The invasion of the orbital apex, optic canal, superior orbital fissure, anterior clinoid, ethmoid-sphenoid sinuses, and infratemporal fossa was evaluated. The rate and extension of involvement of these structures was correlated with the intraorbital location and the surgical approach. The preoperative ophtalmological symptoms and signs and their outcome were also evaluated. Results: Proptosis was found in 79 patients (97%), variable decrease of the visual function in 47 patients (59%), and deficits of the eye movements in 28(35%). The invasion of the optic canal (74%), superior orbital fissure (65%), anterior clinoid (60%), and orbital apex (59%) was more frequently found, whereas the tumor extension into the ethmoid-sphenoid sinuses (4%) and infratemporal fossa (4%) was rare. Types II and III meningiomas showed significantly higher involvement of the skull base structures than type I ones, which only had 15% invasion of the optic canal. Remission or significant improvement of the visual function occurred postoperatively in 24 among 47 cases (51%), with a higher rate for type I meningiomas vs. other types (p = 0.021, p = 0.019) and worsening in 7 (15%). Conclusions: Spheno-orbital meningiomas growing in the lateral orbital compartment show no involvement of the skull base structures excepting the optic canal as compared to those growing medially or diffusely. The surgical resection of tumor invading the skull base structures should be more extensive as possible, but the risk of optic and oculomotor deficits must be avoided. [ABSTRACT FROM AUTHOR]

Many studies revealed that the sphenoid sinus pneumatization (SSP) affects the protrusion/dehiscence of adjacent structures including optic canal (OC), foramen rotundum (FR), vidian canal (VC), and carotid canal (CC). Knowledge of this relationship bears vital importance to identify the safest surgical route during transsphenoidal procedures. Therefore, we aimed to determine the individualized prevalence of the protrusion/dehiscence of adjacent structures based on sagittal and coronal SSP (SSSP and CSSP) patterns. Computed tomography images of 300 patients were analysed to identify the SSSP and CSSP types, and the protrusion/dehiscence of adjacent structures was determined. The relationship between the variables was examined using statistical analysis in terms of age, gender, and laterality. The most prevalent SSSP type was postsellar (62.7%), followed by sellar (30%), presellar (6.6%), and conchal (0.7%). In 71.3% of patients, five types of CSSP were observed, with 23.6% and 21.7% exhibiting Type IV and V, respectively. Our results indicated that postsellar type, Type IV and V CSSP associated with the highest likelihood of protrusion/dehiscence of OC, FR, VC, and CC. Furthermore, no significant correlation was observed between these qualitative variables and gender, with the exception of the VC dehiscence, the protrusion of OC and CC. No notable differences were identified with respect to laterality. Also, the probability of having postsellar type, Type IV and V CSSP, as well as the protrusion of OC, VC, and CC, decreased with increasing age. Further detailed analysis of this association is required to predict the size of the surgical window and to prevent neurovascular injury. [ABSTRACT FROM AUTHOR]

Purpose: To assist in surgical planning in endoscopic approaches, we analyzed the morphometric measurements of the superior orbital fissure (SOF) and optic canal (OC) by three-dimensional multislice computed tomography (3D MDCT) and evaluated them according to age, gender, and lateralization. Methods: The study analyzed 219 MDCT images (114 women, 105 men) from individuals aged 18–90. Measurements of SOF and OC were performed on 3D MDCT images in the axial plane and with 3D-Slicer software. Results: The distance between the infraorbital foramen and the anterior entrance of the maxillary sinus (CBW) (p < 0.001), the distance between the CBW and the lateral point of the SOF (p = 0.001), and the Angle 1 (p = 0.028) were higher in women than in men. While the SOF length and on 3D the SOF width were higher in women than men (p < 0.001 and (p = 0.001, respectively), the lateral wall length OC was higher in men than women (p = 0.045). According to SOF classification, SOF length was highest in type II and lowest in type VIII (p = 0.025), SOF width was highest in type I and lowest in type VI (p < 0.001). No significant difference was found based on age groups and lateralization in all parameters. Conclusion: We found that as the SOF width increased, the SOF length also increased, and there was a statistically strong positive correlation. These findings can contribute to a more effective and safe operation by improving and updating surgeons' knowledge about safe distances to SOF in endoscopic procedures from a 3D MDCT perspective. [ABSTRACT FROM AUTHOR]

Background: The variant morphometry of the optic canal is important to neurosurgeons, radiologists and ophthalmologists in the diagnosis and management of skull base and intracanalicular lesions. Aim and Objectives: This study delved into the anatomical details of the optic canal morphometry, emphasizing its importance in neurosurgical and radiological practices. Materials and methods: Utilizing Computed Tomography (CT) images from a Nigerian Teaching Hospital, we retrospectively assessed the dimensions of the optic canal in 300 adult patients (160 males and 140 females). Rigorous ethical clearance was obtained, and image analysis included measurements of height, width, length of medial and lateral walls, and aperture diameters. Statistical analyses were conducted using SPSS software, examining variations based on age, gender, and side. Results: The left canal demonstrated a wider width, while the right exhibited a longer lateral wall (p < 0.05). Gender differences were noted in orbital and cranial aperture sizes. Agegroup comparisons revealed significant differences in wall lengths and aperture diameters. The optic canal dimensions showed weak positive correlations with age (p < 0.05). Conclusion: This study contributes vital CT measurements of the optic canal, serving as a foundational reference for ophthalmologists, neurosurgeons, and radiologists. The population-specific findings emphasize the optic canal's significance in clinical practice, particularly in the context of surgical interventions and diagnostic precision.

Abstract Background Sphenoid sinus (SS) is an important landmark for endoscopic sinus surgery (ESC) and endoscopic skull base surgery. This study examines the relation of the extent of pneumatization of the sphenoid sinus with adjacent vital structures such as the internal carotid artery, optic canal, and Vidian nerve by using paranasal sinus computed tomography (PNSCT). Methods The study was designed retrospectively. PNSCT images in axial, coronal, and sagittal planes on both sides (right, R; left, L) were examined for sphenoid sinus, Vidian canal (VC), optic canal (OC), and carotid canal (CC) bilaterally. Results The carotid canal did not show identification on the SS wall in females compared to males bilaterally (right, p= 0.002 and left, p= 0.002). The mean age was significantly higher in patients with a presellar type of sphenoid sinus (p=0.003). The mean age was significantly lower on the right side with a VC completely within the sphenoid sinus (p=0.005). The mean age of patients with an optic canal protrudation to the SS wall was significantly higher than patients with an optic canal indentation to the SS wall (p= 0.007). On the left side, cases with an optic canal protruding to the SS wall were older than cases with an optic canal indentation to the SS wall (p= 0.008). SS variations on the sagittal plane were significantly correlated with RVC, RCC, LVC, and LCC variations. Also, SS variations on the coronal plane were significantly related to types of LVC and RVC. Conclusions Pneumatization of SS significantly affects the development of surrounding vital structures, especially with increasing age.

Background: Sphenoid sinus (SS) is an important landmark for endoscopic sinus surgery (ESC) and endoscopic skull base surgery. This study examines the relation of the extent of pneumatization of the sphenoid sinus with adjacent vital structures such as the internal carotid artery, optic canal, and Vidian nerve by using paranasal sinus computed tomography (PNSCT). Methods: The study was designed retrospectively. PNSCT images in axial, coronal, and sagittal planes on both sides (right, R; left, L) were examined for sphenoid sinus, Vidian canal (VC), optic canal (OC), and carotid canal (CC) bilaterally. Results: The carotid canal did not show identification on the SS wall in females compared to males bilaterally (right, p= 0.002 and left, p= 0.002). The mean age was significantly higher in patients with a presellar type of sphenoid sinus (p=0.003). The mean age was significantly lower on the right side with a VC completely within the sphenoid sinus (p=0.005). The mean age of patients with an optic canal protrudation to the SS wall was significantly higher than patients with an optic canal indentation to the SS wall (p= 0.007). On the left side, cases with an optic canal protruding to the SS wall were older than cases with an optic canal indentation to the SS wall (p= 0.008). SS variations on the sagittal plane were significantly correlated with RVC, RCC, LVC, and LCC variations. Also, SS variations on the coronal plane were significantly related to types of LVC and RVC. Conclusions: Pneumatization of SS significantly affects the development of surrounding vital structures, especially with increasing age. [ABSTRACT FROM AUTHOR]

Background Tuberculum sellae meningiomas (TSMs) account for 5 to 10% of all intracranial meningiomas. They typically invade the optic canal and displace the optic nerve upward and laterally. The transcranial approach has been the standard surgical approach, while the transsphenoidal approach has been proposed for its minimally invasive nature; however, some reservations concerning this approach remain. Methods From January 2000 to December 2018, a total of 97 patients who were diagnosed with TSM with invasion of the optic canal were enrolled and underwent microsurgery for tumor removal with optic canal opening. A retrospective analysis was performed on the effect of optic canal opening on postoperative visual acuity improvement. The median follow-up was 17.4 months (range: 3–86 months). Results Among the 97 patients with TSM involving the optic canal, optic canal invasion was seen on preoperative imaging in 73 patients and during intraoperative exploration in all patients. In total, 87/97 patients (89.7%) underwent optic canal opening to remove tumors involving the optic canal, and the rate of total macroscopic resection of tumors invading the optic canal was 100%. Among the 10 patients who did not undergo optic canal opening, the rate of total resection of tumors involving the optic canal was 80% (8/10, p < 0.001). There were no deaths or serious complications. The postoperative visual acuity improvement rate was 64.4%, 23.7% maintained the preoperative level, and the visual acuity deteriorated 11.9%. Conclusion Intraoperative optic canal opening is the key to total resection of TSMs involving the optic canal and improving postoperative visual acuity. [ABSTRACT FROM AUTHOR]

Background: The variant morphometry of the optic canal is important to neurosurgeons, radiologists and ophthalmologists in the diagnosis and management of skull base and intracanalicular lesions. Aim and Objectives: This study delved into the anatomical details of the optic canal morphometry, emphasizing its importance in neurosurgical and radiological practices. Materials and methods: Utilizing Computed Tomography (CT) images from a Nigerian Teaching Hospital, we retrospectively assessed the dimensions of the optic canal in 300 adult patients (160 males and 140 females). Rigorous ethical clearance was obtained, and image analysis included measurements of height, width, length of medial and lateral walls, and aperture diameters. Statistical analyses were conducted using SPSS software, examining variations based on age, gender, and side. Results: The left canal demonstrated a wider width, while the right exhibited a longer lateral wall (p < 0.05). Gender differences were noted in orbital and cranial aperture sizes. Agegroup comparisons revealed significant differences in wall lengths and aperture diameters. The optic canal dimensions showed weak positive correlations with age (p < 0.05). Conclusion: This study contributes vital CT measurements of the optic canal, serving as a foundational reference for ophthalmologists, neurosurgeons, and radiologists. The population-specific findings emphasize the optic canal's significance in clinical practice, particularly in the context of surgical interventions and diagnostic precision. [ABSTRACT FROM AUTHOR]

Abstract Background Lesser wing of sphenoid joins the body of sphenoid by two roots which are separated by the optic canal. Optic canal is a communicating channel between orbit and middle cranial fossa, forming a passage for the ophthalmic artery and optic nerve. Considering the delicate neurovascular structure that traverses the narrow confines of the optic canal, knowledge of the morphometry, anatomical variations of this canal and their relations becomes an important part of diagnostic medicine and surgical management. Objective The aim of the study was to conduct morphometric analysis and document variations of optic canal in north Indian population and study its sexual dimorphism. Material and Method Type of Study Cross-sectional study. Sample size 200 Computerized tomography head axial section scans from picture archiving and communication system. The computer-assisted measurements of optic canal parameters were obtained on both right and left sides. Statistical analysis Unpaired t-test, paired t-test and ANOVA were applied. Result Optic canal of 110 males, 90 females were examined. The overall cranial opening diameter, orbital opening diameter and length of optic canal in males were 4.34 ± 0.74, 3.17 ± 0.58 and 9.81 ± 1.62 and in females they were 3.99 ± 0.71, 2.97 ± 0.59 and 9.38 ± 2.02 respectively. Conclusion Significant gender difference is seen in cranial and orbital opening diameter, and distance from midsagittal plane. No statistical significant difference is observed in right and left side parameters. A thorough knowledge of the normal dimensions of optic canal is important for evaluation and management of cases of optic nerve decompression.

Objectives The authors examined the structural differences in the paranasal sinus region at sphenoid sinus in the pediatric population. Methods Paranasal sinus computed tomography (PNSCT) images of 86 pediatric subjects (30 males, 56 females) were included. In 13 to 15 years of age group (n =34) and ≥16 years of age group (n =52), sphenoid sinus pneumatization (SSP), optic canal and carotid canal classifications and dehiscence evaluation were performed. Results In both sexes, type 1 and type 2 SS pneumatization were observed more frequently on both the right and left sides. On the right side, type 2> type 1; on the left side type 1> type 2 optic canals were detected in both gender. Type 3 optic canals were detected in 8.8 to 14.7% of the 13 to 15 years of age group; and 11.5 to 17.3% of ≥16 years of age group. Type 4 optic canals were detected in 2.9% of the 13 to 15 years of age group and 1.9% of the ≥16 years of age group bilaterally. Optic canal dehiscence was detected in 26.5% of the 13 to 15 years of age group and 17.3% of the ≥16 years of age group. Type 1 and type 2 carotid canals are most common in children, the percentages for type 3 carotid canals were 1.8 to 3.6% in children. Conclusion In pneumatized SS, optic canal classifications got increased values which showed protrusion into the sphenoid sinus wall. Therefore, in children, the surgeons must be very careful for optic canal being nearer to the sphenoid sinus walls. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to classify the morphometry and variations of optic canal by examining its changes according to gender and body side, and developments according to age. Methods: We retrospectively evaluated the orbit and paranasal sinus computerized tomography images of 200 individuals (age range 3 months-90 years;106 female, 94 male). In this study, three different parts of optic canal in evaluated morphometric and morphological. Results: The intracranial aperture was found to be statistically significantly wide in males than females on both sides (p ˂ 0.05). When optic canal types were evaluated, the most common type among healthy individuals was conical type (right: 68%, left:67.5%), and the least common type was irregular type (right and left:1.5%). According to the type of optic waist, the most common was triangle type. Conclusion: Considering the possible effect of optic canal size on pathologies, it is important to establish a basis for the parameters of this structure in healthy individuals. In this study, both the morphology and morphometry of the canal as well as variations were examined and it was determined that the structure was affected by gender, body side and age group. Knowledge of anatomic morphometry, variations and complexities arising from these are important for clinical diagnosis and management. [ABSTRACT FROM AUTHOR]

Neoplasms of the orbit may be primary, secondary (infiltration from the adjacent structures), or metastatic (from distant structures). It can be divided into 3 histologic categories: benign, benign but locally aggressive, and malignant. Primary and secondary orbital tumors, including intra-orbital and optic nerve tumors are uncommon observations in daily medical practice. Orbital tumors represent approximately 0.1% of all tumors and approximately 18% of all orbital diseases.We report a case of a 42 year old male patient with colorectal malignancy with basal skull metastasis involving the orbital apex and involving the optic nerve causing visual loss.

Background: Anterior clinoidectomy is an established procedure used to decompress the optic nerve, mobilize the internal carotid artery (ICA), or enlarge the retrocarotid space. However, its use carries the risk of optic nerve injury. In certain surgeries, such as those for internal carotid aneurysms, propose modification to the anterior clinoidectomy for enlarging the retrocarotid space, especially in operations for ICA aneurysms. Methods: After the anterior clinoid process (ACP) is sufficiently exposed, the internal cancellous bone or pneumatization can be removed through a small window created at its lateral edge to reveal the compact bone of the optic canal. Since the compact bone of the inferior surface facing the ICA is absent or very thin, the ACP can be removed by drilling through the anchoring compact bone with the optic canal in direct sight. Results: In 10 consecutive internal carotid aneurysm cases, the ACP was successfully removed without opening of the optic canal to enlarge the retrocarotid space. Conclusions: Anterior clinoidectomy can be performed to enlarge the retrocarotid space without opening the optic canal from outside the dura.

Introduction: Existing data regarding the relative position of the various bony landmarks of the orbit suggest that the position of these landmarks may vary depending on the racial population studied. The present study will provide useful baseline orbital morphometric data in Eastern Indian population. Aim: To study the morphometric data of the different orbital dimensions, fissures and foramens of dry skulls in Eastern Indian region. Materials and Methods: This cross-sectional study was done in the department of Anatomy, of a Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India from January 2016 to June 2020. Total 101 adult dry skulls (71 male and 30 female) collected from the departments of Anatomy of four medical colleges were included in the study. Orbital height, breadth, index, distance between Supraorbital Notch/foramen (SON) to Superior Orbital Fissure distance (SOF), the Anterior Lacrimal Crest (ALC) to Posterior Lacrimal Crest (PLC), ALC to the medial border of the optic canal, orbital floor and lateral wall were measured. Results: Based on Orbital Index (OI) 39.12% skulls were found to be in mesoseme, 50.5% in microseme and 10.4% in megaseme category, both genders taken together. The mean SON to SOF distance was 42.48 mm in males and 41.52 mm in females. Mean Infraorbital Foramen (IF) to Inferior Orbital Fissure (IOF) distance was 22.4 mm in males and 22.26 mm in females. Average Frontozygomatic Suture (FZ) to Inferior Orbital Fissure (IOF) was 24.35 mm whereas it was 32.97 mm for the ALC to Optic canal (OC) distance. Conclusion: Most of the skulls studies belonged to the microseme category. Orbital height and breadth were significantly higher in males compared to females.

Purpose: A detailed understanding of the neurovascular relationships between the optic nerve (ON) and the ophthalmic artery (OA) in the optic canal (OC) is paramount for safe surgery. We focused on the neurovascular anatomy of this area from both an endoscopic endonasal and transcranial trajectories to compare the surgical exposures and perspectives offered by these different views and provide recommendations to increase the intraoperative safety. Methods: Twenty sides of ten formalin-fixed, latex-injected head specimens were utilized. The surgical anatomy and anatomical relationships of the OA in relationship to the ON along their intracranial and intracanalicular segments was studied from endoscopic endonasal and transcranial perspectives. Results: Three types of OA-ON relationships at the origin of the OA were identified: inferomedial (type 1, 35%), inferior (type 2, 55%), and inferolateral (type 3, 10%). The endoscopic endonasal trajectory offers an inferomedial perspective of the ON-OA neurovascular complex, in which the OA, especially when located inferomedially, is first encountered. When comparing with the transcranial view, all OA were covered by the nerve, type 1 was located below the medial third, type 2 below the middle third, and type 3 below the lateral third of the OC. The mean extension of the intracanalicular portion of both OA and ON was 8.9 mm, while the intracranial portion of the OA and ON were 9.3 mm and 12.4 mm, respectively. The OA, endoscopically, is located within the inferior half of the OC, and occupies 39%, 43%, and 42% of the OC height at its origin, mid, and end points, respectively. The mean distance between the superior margin of the OC at its origin and superior margin of the OA is 1.4 mm. Conclusions: Detailed anatomical understanding of the OC, and the ON and OA at their intracranial and intracanalicular segments is paramount to safe surgery. When opening the OC dura endoscopically, our results suggest that a medial incision along the superior third of the OC with a proximal to distal direction is recommended to avoid injury of the OA. [ABSTRACT FROM AUTHOR]

ObjectiveTo present a surgical treatment regimen of transnasal endoscopic decompression through the optic strut for traumatic oculomotor nerve palsy based on the anatomical study of the superior orbital fissure and the oculomotor nerve fissure segment.MethodsThe bone structure of the oculomotor nerve fissure segment and the important bone anatomical landmarks of the lateral wall of the sphenoidal sinus were identified on a dried skull and a cadaveric head, respectively, using a nasal endoscope, and a surgical plan was determined. Decompression was conducted on the orbital apex, the superior orbital fissure, the optic canal and the optic strut of the two patients in sequence, after which the degree and range of decompression were identified by three-dimensional (3D) computed tomography (CT).ResultsThe oculomotor nerve had a close correlation with the lateral surface of the optic strut. The transnasal endoscope was employed to identify the lateral optic-carotid recess (LOCR), as well as the positions of the optic nerve, internal carotid artery (ICA), and superior orbital fissure, collectively called the “optic strut triangle”. The surgical plans for decompression of the orbital apex, superior orbital fissure, optic canal, and optic strut and the necessity of optic strut drilling were determined, and the surgical procedures for safe drilling of the optic strut were elaborated. After surgery, the two patients had significantly improved symptoms, without complications. In addition, their postoperative CT showed that the medial margin of the superior orbital fissure was fully decompressed.ConclusionThe optic strut triangle is a crucial anatomical landmark in the decompression of the oculomotor nerve, and optic strut drilling is necessary for such decompression. For patients with traumatic oculomotor nerve palsy and fractures of the medial wall of the superior orbital fissure on CT, the oculomotor nerve fissure segment can be decompressed in an effective, complete and safe manner as per the surgical plan of decompressing the orbital apex, superior orbital fissure, optic canal and optic strut in turn under a transnasal endoscope, conducive to the recovery of neurological function of patients.

Introduction  Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy. Methods  Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally. Results  The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12–15 mm) and 12.4 mm (range 10–16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205–280 degrees) and 124.6 degrees (range 100–163 degrees), respectively. Conclusion  The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort. [ABSTRACT FROM AUTHOR]

The extent of resection constitutes one of the most important predictive risk factors of recurrence for spheno-orbital meningiomas; although gross total resection represents the gold standard, it is not always achievable, with a consequent high rate of recurrence. Management of these tumors is a surgical challenge and is represented by maximal safe resection with preservation of function. The aim of the present study is to discuss the risk factors for recurrence and the best management of the recurrent tumors. Eighty patients operated on for spheno-orbital meningiomas were retrospectively reviewed. Two groups were identified: group 1 comprised 30 patients (37.5%) who experienced recurrence and group 2 comprised 50 patients with no recurrence from 5 to 28 years after the initial surgery. The analyzed factors in both groups include the involvement of the skull base structures, the extent of resection, and World Health Organization grade. In the recurrence group, the pattern of tumor regrowth, the entity of resection, and the management were also analyzed. The invasion of the whole orbit, the involvement of the orbital apex, superior orbital fissure, infratemporal fossa, and sphenoidal-ethmoidal sinuses, and World Health Organization grade II are risk factors of recurrence. All 30 patients with recurrence underwent reoperation, 9 of whom had 2 or 3 reoperations. Overall, 70 of the 80 patients (88%) had tumor control and no progression after one or more reoperations. We suggest re-surgery for spheno-orbital meningioma recurrences to prevent worsening of visual function and proptosis. Because of their slow natural course, even multiple reoperations may be performed, resulting in long overall survival with stable symptoms and good quality of life. [ABSTRACT FROM AUTHOR]

ObjectiveThe surgical management of lesions involving the lateral area of the suprasellar region, including the lateral aspect of the planum sphenoidale and the tight junction region of the optic canal (OC), anterior clinoid process (ACP), and internal carotid artery (ICA) and its dural rings, is extremely challenging. Here, these regions, namely, the “parasuprasellar” area, are described from the endonasal perspective. Moreover, the authors introduce two novels endoscopic endonasal supraoptic (EESO) and endoscopic endonasal infraoptic (EEIO) approaches to access the parasuprasellar area.MethodsSurgical simulation of the EESO and EEIO approaches to the parasuprasellar area was conducted in 5 silicon-injected specimens. The same techniques were applied in 12 patients with lesions involving the parasuprasellar area.ResultsThe EESO approach provided excellent surgical access to the lateral region of the planum sphenoidale, which corresponds to the orbital gyrus of the frontal lobe. With stepwise bone (OC, optic strut and ACP) removal, dissociation of the ophthalmic artery (OA) and optic nerve (ON), the EEIO approach enables access to the lateral region of the supraclinoidal ICA. These approaches can be used independently or in combination, but are more often employed as a complement to the endoscopic endonasal midline and transcavernous approaches. In clinical application, the EESO and EEIO approaches were successfully performed in 12 patients harboring tumors as well as multiple aneurysms involving the parasuprasellar area. Gross total and subtotal tumor resection were achieved in 9 patients and 1 patient, respectively. For two patients with multiple aneurysms, the lesions were clipped selectively according to location and size. Visual acuity improved in 7 patients, remained stable in 4, and deteriorated in only 1. No postoperative intracranial infection or ICA injury occurred in this series.ConclusionsThe EESO and EEIO approaches offer original treatment options for well-selected lesions involving the parasuprasellar area. They can be combined with the endoscopic endonasal midline and transcavernous approaches to remove extensive pathologies involving the intrasellar, suprasellar, sphenoid, and cavernous sinuses and even the bifurcation of the ICA. This work for the first time pushes the boundary of the endoscopic endonasal approach lateral to the supraclinoidal ICA and ON.

The aim of this study was to compare optic canal parameters of syndromic craniosynostosis patients with those of normal patients to visit the possibility of optic nerve impingement as a cause of visual impairment. Computed tomography scan images were processed using the Materialise Interactive Medical Image Control System (MIMICS) Research 21.0 software (Materialise NV, Leuven, Belgium). Eleven optic canal parameters were measured: 1) height of optic canal on the cranial side, 2) height of optic canal on the orbital side 3) length of the medial wall of the optic canal, 4) length of the lateral canal wall of the optic canal, 5) diameter of the optic canal at five points (Q1-Q4 and mid canal), and 6) area and perimeter of optic canal. These measurements were obtained for both the right and left optic canals. The study sample comprised four Crouzon syndrome, five Apert syndrome, and three Pfeiffer syndrome patients. The age of these syndromic craniosynostosis patients ranged from 2 to 63 months. The height of the optic canal on the orbital side (p = 0.041), diameter of the mid canal (p = 0.040), and diameter between the mid-canal and the cranial opening (Q3) (p = 0.079) for syndromic craniosynostosis patients were statistically narrower compared with those of normal patients when a significance level of 0.1 was considered. Scatter plots for the ages of patients versus the above parameters gave three separated clusters that suggested the arresting of optic canal development with age. The findings from this study demonstrated a narrowing of the optic canal in syndromic craniosynostosis patients, and indicate that optic canal anatomical characteristics may have an association with visual impairment among pediatric syndromic craniosynostosis patients. [ABSTRACT FROM AUTHOR]

Background: Congenital optic canal stenosis causing compressive optic neuropathy is a rare disorder that presents unique diagnostic and treatment challenges. Endoscopic endonasal optic nerve decompression (EOND) has been described for optic nerve compression in adults and adolescents but has never been reported for young children without pneumatized sphenoid sinuses. The authors describe preoperative and intraoperative considerations for three patients younger than 2 years of age with congenital optic canal stenosis due to genetically confirmed osteopetrosis or chondrodysplasia., Observations: Serial ophthalmological examinations, with a particular focus on object tracking ability, fundoscopic examination, and visual evoked potential trends in preverbal children, are important for detecting progressive optic neuropathy. The lack of pneumatization of the sphenoid sinus presents unique challenges and requires the surgical creation of a sphenoid sinus with the use of neuronavigation to determine the limits of bony exposure given the lack of easily identifiable anatomical landmarks such as the opticocarotid recess. There were no perioperative complications., Lessons: EOND for congenital optic canal stenosis is safe and technically feasible even given the lack of pneumatization of the sphenoid sinus in young patients. The key operative step is surgically creating the sphenoid sinus through careful bony removal with the aid of neuronavigation. https://thejns.org/doi/10.3171/CASE23559.

Background: The aim of the study was to describe the comprehensive morphological and morphometric features of the foramina and canals at the base of the cranial cavity in Holstein cow using CT images., Materials and Methods: The study was performed on fourteen adult Holstein cow head cadavers. Images taken with MSCT were transferred to the DICOM Viewer program. The MPR and 3D reconstructive tools of the program were used to analyse the foramina and canals., Results: Although they varied in shape and size, foramina and canals were found bilaterally in all animals. It was observed that the orbitorotund foramen, jugular foramen and oval foramen had a canalicular structure, with the distance between the extra-intra cranial openings measured as 15.0 mm, 5.9 mm and 6.2 mm, respectively. The hypoglossal canal, which was found to be single in 43%, double in 50% and triple in 7% in each body half, was the canal with the most variation in number and shape. The orbitorotund foramen, a canal with an area of 180.6 mm² and a diameter of 18.1 × 12.4 mm is the widest at the skull base, while the optic canal is the narrowest and longest opening with an area of 33.4 mm², a diameter of 8.4 × 5.5 and a length of 17.5 mm., Conclusions: This study shows that our knowledge of skull base morphometry in animals is extremely limited. Although the study was conducted on a limited number of materials, it may benefit both regional anatomy knowledge in terms of the data presented and veterinary anatomists, radiologists and clinicians in terms of methodology.

Background Different types of skull base tumors and intracranial aneurysms may lead to compression of the optic pathways. Since most of them are biologically benign conditions, the first aim of surgery is preservation of optic nerves rather than the oncologic radicality. Materials and methods Based on the progressive technical refinements coming from our institutional experience of optic nerve compression from aneurysms and extra-axial tumors, we analyzed the surgical steps to release nerves and chiasm during tumor debulking and aneurysm clipping. Results We distinguished vascular and tumor lesions according to the main direction of optic nerve compression: lateral to medial, medial to lateral, inferior to superior, and anterior to posterior. We also identified four fundamental sequential maneuvers to release the optic nerve, which are (1) falciform ligament (FL) section, (2) optic canal unroofing, (3) anterior clinoid process drilling, and (4) optic strut removal. The FL section is always recommended when a gentle manipulation of the optic nerve is required. Optic canal unroofing is suggested in case of lateral-to-medial compression (i.e., clinoid meningiomas), medial-to-lateral compression (i.e., tuberculum sellae meningiomas), and inferior-to-superior compression (i.e., suprasellar lesions). Anterior clinoidectomy and optic strut removal may be necessary in case of lateral-to-medial compression from paraclinoid aneurysms or meningiomas. Conclusions Preservation of the visual function is the main goal of surgery for tumors and aneurysms causing optic nerve compression. This mandatory principle guides the approach, the timing, and the technical strategy to release the optic nerve, and is principally based on the direction of the compression vector. [ABSTRACT FROM AUTHOR]

Pneumosinus dilatans of the sphenoid sinus is a rare disorder which can be responsible for visual impairment and blindness. We present the case of an adolescent female who experienced progressive decrease in right-eye vision over 2 years. CT scan of the head showed an extensive pneumatization of the sphenoid bone extending to the lesser wing of the sphenoid and to the anterior clinoid process on the right side. MRI revealed right nerve atrophy in the optic canal and in the posterior part of the orbit. A surgical decompression of the right optic canal was performed via an intradural fronto-pterional approach. Postoperatively, her vision worsened, and at 3 years the patient was able to count fingers at 2.5 m. Our case and literature review of symptomatic sphenoidal pneumosinus dilatans confirmed that visual prognosis in such cases depended on the preoperative visual status. Early surgical decompression should be proposed whenever possible, before signs of severe visual disorders and optic atrophy. [ABSTRACT FROM AUTHOR]

Hypertrophic pachymeningitis refers to linear or nodular thickening of the dura mater covering the brain and spinal cord following various inflammatory/infective processes. Usually, magnetic resonance imaging brain shows uniform thickening with enhancement of involved meninges. Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) findings of pachymeningitis are rarely reported in literature. We describe the PET/CT findings of a patient with hypertrophic pachymeningitis involving the bilateral supraorbital regions depicting as "eyebrows" on brain maximum intensity projection image. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to peruse anatomic features of the cranial aperture of the optic canal (CAOC) for obtaining an extended morphometric dataset in children. Methods: Computed tomography images of 200 children were included in this retrospective work to analyze the shape, location and diameters of the CAOC. Results: The CAOC area, width and height were observed as 17.53 ± 2.80 mm2, 6.12 ± 0.84 mm, and 4.35 ± 0.64 mm, respectively. The angle of the optic canal in axial plane was found as 39.28 ± 5.13°, while in sagittal plane as 16.01 ± 6.76°. The distance between the CAOC and the midsagittal line was 7.17 ± 1.48 mm. The CAOC was measured as 54.04 ± 5.23 mm and 42.55 ± 3.28 mm away from the anterior and lateral boundary of the anterior skull base, respectively. The CAOC shape was described as the tear-drop (186 foramina, 46.5%), triangular (156 foramina, 39%), oval (47 foramina, 11.8%), and round (11 foramina, 2.8%). Conclusion: The depth, angle and diameter measurements belonging to the CAOC were changing according to its shape or demographic data (e.g., sex and age). Therefore, preoperative radiologic evaluation containing the shape, location and size of the CAOC should be considered by multidisciplinary operating teams in terms of surgical interventions such as implant positioning. [ABSTRACT FROM AUTHOR]

Background and objectives: The aim of this study was to evaluate the ability of recognizing some important elements of the skull base in axial CT-scan cuts, including the optic canal (OC), superior orbital fissure (SOF), vidian canal (VC), foramen rotundum (FR), jugular foramen (JF) and hypoglossal canal (HC). Methods: In this study, 25 otolaryngology residents and 25 recently graduated otolaryngologists were evaluated in terms of their recognition of skull base elements, using 30 axial CT-scan cuts. Two months later, the exam related to skull base CT scans was taken in groups after a brief anatomy courses for otolaryngology residents. Results: The percentage of correct answers from otolaryngology residents regarding OC, SOF, VC, FR, JF, and HC in the first exam were 74 ± 26, 47 ± 34, 65 ± 30, 41 ± 38, 58 ± 26, and 68 ± 32, respectively. The correct answer for each element was similar between groups, and the differences were not statistically significant (p > 0.05). p value for the differences observed regarding the percentage of correct answers for the second exam between trained otolaryngology residents and recent otolaryngology graduates regarding OC and JF was no significant (p > 0.05) but significant for the other elements with better result in trained otolaryngology residents and most for SOF (p > 0.0001). Conclusion: This study showed that the ability of recognition for the mentioned elements in axial CT-scan cuts was low among otolaryngology residents and graduated otolaryngologists. The proposed novel method for distinguishing SOF from OC had a powerful and long-lasting effect on trainee. [ABSTRACT FROM AUTHOR]

Objective: This study describes an innovative optic nerve MRI protocol for better delineating optic nerve anatomy from neighboring pathology., Methods: Twenty-two patients undergoing MRI examination of the optic nerve with the dedicated protocol were identified and included for analysis of imaging, surgical strategy, and outcomes. T2-weighted and fat-suppressed T1-weighted gadolinium-enhanced images were acquired perpendicular and parallel to the long axis of the optic nerve to achieve en face and in-line views along the course of the nerve., Results: Dedicated optic nerve MRI sequences provided enhanced visualization of the nerve, CSF within the nerve sheath, and local pathology. Optic nerve sequences leveraged the "CSF ring" within the optic nerve sheath to create contrast between pathology and normal tissue, highlighting areas of compression. Tumor was readily tracked along the longitudinal axis of the nerve by images obtained parallel to the nerve. The findings augmented treatment planning., Conclusions: The authors present a dedicated optic nerve MRI protocol that is simple to use and affords improved cross-sectional and longitudinal visualization of the nerve, surrounding CSF, and pathology. This improved visualization enhances radiological evaluation and treatment planning for optic nerve lesions.

Objective In this radioanatomical study, we aimed to obtain data on the morphometric properties of the optic strut as it is an important reference point for optic nerve surgery. Material and Methods Seven adult human dry skulls, present in the inventory of Faculty of Medicine Department of Anatomy were included in this study. Direct anatomical measurements were obtained with a digital caliper and radiological measurements with computed tomography. The position of the optic strut was evaluated according to the preciasmatic sulcus. Results The length and width of the optic strut were 4.53 ± 0.74 mm and 4.83 ± 1.34 mm in direct anatomic measurements. On computed tomography, the length and width of the optic strut were 4.13 ± 1.27 mm and 4.31 ± 0.82 mm. The distance between the two struts was 16.83 ± 2.56 mm and 15.91 ± 1.81 mm in direct anatomic measurements and computed tomography, respectively. Computed tomography and direct anatomic evaluation revealed that the optic strut was sulcal in 4 dry skulls, postsulcal in 2 dry skulls, and asymmetric in 1 dry skull. Conclusion Considering the fact that optical strut is a landmark for surgeons and may be damaged during anterior clinoid process resection, our numerical data may be useful during surgical applications around the optic nerve. [ABSTRACT FROM AUTHOR]

Objective Anatomic variability of the optic strut in location, orientation, and dimensions is relevant in approaching ophthalmic artery aneurysms and tumors of the anterior cavernous sinus, medial sphenoid wing, and optic canal. Methods In 84 dry human skulls, imaging studies were performed (64-slice computed tomography [CT] scanner, axial view, aligned with the zygomatic arch). Optic strut location related to the prechiasmatic sulcus was classified as presulcal, sulcal, postsulcal, and asymmetric. Morphometric analysis was performed. Results The optic strut was presulcal in 11.9% specimens (posteromedial margin bilaterally anterior to limbus sphenoidale), sulcal in 44% (posteromedial part adjacent to the sulcus's anterior two thirds bilaterally), postsulcal in 29.8% (posteromedial margin posterior to the sulcus's anterior two thirds), and asymmetric (left/right) in 14.3%. Optic strut length, width, and thickness measured 6.54 ± 1.69 mm, 4.23 ± 0.69 mm, and 3.01 ± 0.79 mm, respectively. Optic canal diameter was 5.14 ± 0.47 mm anteriorly and 4.79 ± 0.64 mm posteriorly. Angulation was flat (>45 degrees) in 13% or acute (

Isolated orbital roof fractures are raremost of these fractures heal without any complications. Traumatic optic neuropathy (TON) is one of the rare but catastrophic complications of orbital roof fractures. A 37-year-old gentleman was admitted in our emergency department following road traffic accident. He fell down from a motocycle, on presentation to the emergency department he felt a little drowsy, had vomited twice, and complained of pain around his right eye. His Glasgow Coma Scale was 15/15. Clinical examination revealed right periorbital hematoma with edematous lids closing the right eye and ecchymosis, and pupils were equal in size. Eye movements was normal but visual acuity in the right eye was 2/10 and in left 9/10. CT scan of the facial bones (slice thickness 1 mm) demonstrated a comminuted right orbital roof ´blow-in´ fracture (A,B,C,D) with associated non-displaced linear fracture extension towards the optic canal fracture. Magnetic resonance imaging MRI axial T2 flair showed a contusion of the right optic nerve (A,B,C,D). Traumatic optic neuropathy (TON) refers to optic nerve damage secondary to trauma, which occurs in approximately 0.5-5% of head injuries and 2.5% of patients with maxillofacial trauma and facial fractures. It is defined as any damage to the optic nerve secondary to trauma that may occur primarily or secondarily to the initial insult. It is crucial to make an appropriate diagnosis of orbital roof fracture if present because of its possible medical implications like enophthalmos or proptosis, facial asymmetry, visual loss, and eye movement restriction.

Purpose: Detection of optic canal fractures is often difficult because of the subtleness of the fracture. If we could clarify impact on which region around the orbit is likely to accompany the fracture of the optic canal, the knowledge should be useful to make early diagnosis of optic canal fractures. The present study was conducted to elucidate this issue. Methods: Ten finite element models were produced simulating the skulls of ten humans (8 males and 2 females; 43.8 ± 10.2 y/o). The peri-orbital area of each of the ten models was divided into eight regions in a clockwise fashion per 45 degrees. These regions were defined as Superior-Medial (0–45 degrees), Medial-Superior (45–90 degrees), Medial-Inferior (90 to 135 degrees), Inferior-Medial (135 to 180 degrees), Inferior-Lateral (180–225 degrees), Lateral-Inferior (225 to 270 degrees), Lateral-Superior (270–315 degrees), and Superior-Lateral regions (315–360 degrees), respectively. Dynamic simulation of applying traumatic energy on each of these regions was conducted. Resultant fracture patterns were evaluated using finite element analyses. Thereafter, frequencies of fracture involvement of the optic canal were evaluated for each of the eight regions. Results: The involvement of the optic canal was most frequent for the Superior-Medial region (7/10), followed by the Medial-Superior region (5/10). Conclusion: Optic canal fracture is likely to occur when the area between the supra-orbital notch and the medial canthus are strongly impacted. When evident fracture or serious damage of soft tissue is observed in this area, occurrence of optic canal fracture should be suspected.

Background: There are neuro-ophthalmologic findings in patients with communicant hydrocephalus (CH).Purpose: To investigate the relationships of the optic canal and carotid canal classifications at sphenoid sinus and anterior clinoid process (ACP) pneumatization in patients with CH.Material and Methods: In this multicentric retrospective cross-sectional study, the cranial computed tomography (CT) images of 38 patients with CH (20 men, 18 women) and 40 controls (25 men, 15 women) were included. Optic and carotid canal classification at sphenoid sinus, ACP pneumatization, and sphenoid sinus septation were evaluated.Results: In the CH group, type 3 optic canal was detected in 21.1% of the patients and type 4 optic canal was detected in 2.6% of the patients on the left side which was significantly different from the control group (P<0.05). In the CH group, type 3 carotid canal was detected in 21.1% of the patients (left) and 18.4% of the patients (right). ACP pneumatization was present in 13.2% of the patients in the CH group bilaterally. There were positive correlations between optic canal classifications and ACP pneumatization (P<0.05). There were also positive correlations between the right and left carotid canal classifications and ACP pneumatization (P<0.05).Conclusion: To avoid complications, CT should be evaluated carefully in patients with CH before surgical interventions in sphenoid sinuses and surgeons should work carefully in the sphenoid sinus or adjacent structures. The protrusion possibility of the optic canal or carotid canal to the sphenoid sinus may be higher in pneumatized ACP patients. [ABSTRACT FROM AUTHOR]

The orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation. A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity. This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies. [ABSTRACT FROM AUTHOR]

Advances in skull base and orbital surgery have led to an increased need to understand the anatomy of the orbit and surrounding structures to safely perform surgeries in this area. The purpose of this article is to review the surrounding anatomy of the orbit from a practical and operative point of view. We describe the orbit from an inferomedial endoscopic endonasal perspective (focusing on its inferior relationship with the maxillary sinus and related structures and its medial relationship with the ethmoid bone), from a posterior and superolateral intracranial perspective (describing the anatomy of the superior orbital fissure, optic canal, inferior orbital fissure, cavernous sinus, orbitofrontal cortex, and surrounding dura) and from an anterior perspective (focusing on the muscles, connective tissue, lateral and medial canthus, and relevant neurovascular anatomy). A deep knowledge of the critical neurovascular and osseous structures surrounding the orbit is necessary for adequately choosing and performing the most favorable orbital approach in every case. [ABSTRACT FROM AUTHOR]

Frontolateral craniotomy procedures have advanced from conventional craniotomy to mini-craniotomy, and to contemporary keyhole surgery. In this context, it is important for the neurosurgeon to precisely locate the pterion. The distance of the pterion center from midpoint of zygomatic arch and posterolateral margin of frontozygomatic suture was studied bilaterally in 50 whole adult skulls in Indian ethnic group. The depth of optic canal and sphenoid ridge from the pterion was recorded bilaterally in fifty cut adult skulls and fifteen three-dimensional computed tomography scans. The suture length, thickness, and morphology were studied. The data were analyzed using SPSS software, two-tailed Student's t test, binary logistic regression and receiver operating characteristic curve for sexual dimorphism. The pterion center was located at a mean distance of 37.02 mm above the midpoint of zygomatic arch, 28.20 mm behind the posterolateral margin of frontozygomatic suture, 42.73 mm lateral to the optic canal and 10.59 mm from the sphenoid ridge. The location did not exhibit sexual dimorphism. In 20% cases the pterion center was 40 mm or more above the midpoint of the zygomatic arch and in 5% cases 35 mm or more posterior to the posterolateral margin of frontozygomatic suture. The mean suture length was 10±3 mm. The mean thickness at the center of the pterion was 3.52±1.45 mm. The commonest variety was sphenoparietal followed by frontotemporal, epipteric, and stellate types. A thorough knowledge of these dimensions has innumerable neurosurgical implications in resection of sellar, parasellar, and paraclinoid tumors and circulatory aneurysms. [ABSTRACT FROM AUTHOR]