Ophthalmic artery originating from the anterior cerebral artery: anatomo-radiological study, histological analysis, and literature review

Morphometric Analysis of the Ophthalmic and Central Retinal Arteries via the Endoscopic Endonasal Trans-ethmoidal Approach: Surgical Relevance of Vascular Components Within the Medial Intraconal Zones

BACKGROUND

The endoscopic endonasal approach (EEA) offers a minimally invasive route to treat medial intraconal space (MIS) lesions. Understanding the configuration of the ophthalmic artery (OphA) and the central retinal artery (CRA) is crucial.

METHODS

An EEA to the MIS was performed on 30 orbits. The description of the intraorbital part of the OphA was divided into 3 segments and classified as type 1 and type 2 and the MIS was divided into three surgical zones (A, B, C). The CRA's origin, course, and point of penetration (PP) were analyzed. The relationship between the position of the CRA in the MIS and the OphA type was analyzed.

RESULTS

The OphA type 2 was present in 20% of specimens. The site of origin of the CRA from the OphA was found on the medial surface in type 1 and on the lateral surface of type 2. The point of penetrationof the central retinal arterywas found in 87% of the specimens on the inferomedial surface, just anterior to the inferior muscular trunk, at an average distance of 9.5 mm ± 1 from the globe and 17 mm ± 1.5 from the AZ. The presence of the CRA in Zone C was associated only with OphA type 1.

CONCLUSIONS

OphA type 2 is a common finding and can compromise the feasibility of an EEA to the MIS. A detailed preoperative analysis of the OphA and CRA should be conducted prior to approaching the MIS due to the implications of the anatomical variations that can compromise safe intraconal maneuverability during an EEA.

Ophthalmic artery arising from the external carotid artery system: the middle meningeal artery in South African patients

BACKGROUND

The ophthalmic artery is the first branch of the internal carotid artery. It arises from the supraclinoid segment of the internal carotid artery within the subarachnoid space and enters the orbit via the optic canal. However, due to complex embryogenesis, the ophthalmic artery can arise from different parts of the internal carotid artery or the distal branches of the external carotid artery. This is usually associated with a variation in the course of the ophthalmic artery through the superior orbital fissure instead of coursing through the optic canal. The ophthalmic artery and its branches vascularise the eyeball and its contents. Consequently, information about its morphologic variation is essential for treating clinical conditions such as central retinal artery occlusion, retinoblastoma chemoembolization, and ophthalmic artery aneurysm.

CASE PRESENTATION

We report on two cases of the ophthalmic artery arising from the middle meningeal artery in one adult (33-year-old Indian female) and one pediatric (2-year-old African male) South African patient examined by digital subtraction angiography. The patients were diagnosed with arteriovenous malformations and bilateral retinoblastoma, respectively.

CONCLUSIONS

The ophthalmic artery plays a vital role in vision generation. Thus, its anatomy is of clinical interest to neurosurgeons, ophthalmologists, and interventional radiologists.

Endoscopic endonasal surgical anatomy of the optic canal: key anatomical relationships between the optic nerve and ophthalmic artery

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.

Investigation into the ophthalmic artery and its branches by superselective angiography

BACKGROUND

The vascular anatomy of orbit is highly complex, and the main blood supply to the orbit is via the ophthalmic artery, which is a branch of the internal carotid artery. The purpose of this study was to determine the morphometry of the ophthalmic artery and its branches by superselective angiography in a large series of pediatric patients.

METHODS

We evaluated 134 angiographies performed on children with intraocular retinoblastoma undergoing intra-arterial chemotherapy. The origin, diameter, and angiographic visibility percentages of the ophthalmic artery and its branches were examined according to age group and sex.

RESULTS

The ophthalmic artery originated 97.8% from the internal carotid artery and 2.2% from the middle meningeal artery. The mean diameter of ophthalmic artery was measured 0.76 ± 0.14 mm in girls, 0.80 ± 0.15 mm in boys and 0.79 ± 0.15 mm in general. The posterior ciliary, lacrimal, inferior muscular, and anterior ethmoidal arteries had a higher angiographic visibility percentages (> 85%) than the other OA branches. Only the diameter of the dorsal nasal artery showed a significant correlation with age. The supratrochlear and posterior ciliary arteries showed statistically significant relationship with sex.

CONCLUSIONS

Present study will make a substantial contribution to the pediatric literature about the ophthalmic artery and its branches. A better understanding of ophthalmic artery morphology can help surgeons and neurointerventional radiologists to avoid possible severe complications during embolization, intra-arterial chemotherapy, cosmetic procedures, endonasal and orbital surgeries.

When is a multidisciplinary surgical approach required in sinonasal tumours with cranial involvement?

The term “sinonasal tumours” includes a large spectrum of diseases, which are characterized by heterogeneous biological behavior and prognosis, and located in a critical anatomic area. Diagnosis and treatment of sinonasal tumours require the contribution of different disciplines. A narrative review was performed to highlight the role of surgeons in contributing to a multidisciplinary approach to sinonasal tumours. Diagnosis and staging of sinonasal tumours is challenging and requires collaboration between surgeons, radiologists, and pathologists. The identification and management of critical extensions (orbital or intracranial encroachment, vascular abutment or encasement) is fundamental for successful treatment. Most cases of advanced sinonasal tumours can undergo surgical intervention by an adequately trained otorhinolaryngological team. The contribution of neurosurgeons and oculoplastic surgeons is required in selected scenarios. In rare circumstances, multidisciplinary reconstructive strategies can be indicated for complex tissue defects. Furthermore, a multidisciplinary approach is pivotal in the management of perioperative complications. While surgery remains the mainstay of treatment, the role of non-surgical adjuvant or even exclusive treatments is constantly expanding.

Role of the ophthalmic artery in the endovascular treatment for intracranial vascular diseases

The ophthalmic artery (OA) is a crucial artery. Centered at the OA, there are numerous extracranial-intracranial anastomoses. The OA and its collaterals can be involved in some intracranial vascular diseases. So, it is very important to understand its specific anatomy, variation, and role in different neurovascular diseases. The OA has various anomalies both in the origin and collateral circulation. When performing endovascular treatment (EVT), the OA may suffer unexpected embolization through the numerous dangerous anastomoses. In case of a dural arteriovenous fistula or brain arteriovenous malformation mainly fed by the OA, the OA can be the passage of EVT, during which the central retinal artery could be injured. During interventional recanalization of steno-occlusive diseases of the internal carotid artery, dissection at the cavernous segment could progress to the OA segment and occlude the origin of OA. Under the circumstance of moyamoya disease, the OA can provide collateral flow to the anterior cerebral artery. When performing EVT for OA aneurysm concurrent with moyamoya disease, the parent OA should be preserved. After placement of a flow-diverting device for ophthalmic ICA aneurysm, the covered OA could experience spontaneous occlusion, leading to visual disturbance. Hence, the OA is an extremely important artery in the EVT for intracranial vascular diseases. In this article, we would extensively review the related literature to increase our understanding of the role of OA in intracranial vascular diseases. In addition, some illustrative cases would also be provided.

A systematic review of the surgical anatomy of the orbital apex

PURPOSE

The orbital apex is the narrowest part of the orbit, housing the link between the intracranial cavity and orbit. Knowledge of orbital apex anatomy is crucial to selecting a surgical approach and reducing the risk of complications. Our purpose is to summarize current knowledge on surgical anatomy and attempt to reach a consensus on definition of the orbital apex.

METHODS

The online databases of Embase, the Cochrane library, Web of Science and PubMed (MEDLINE) were queried in a comprehensive bibliographic search on the (surgical) anatomy of the orbital apex and consisted of a combination of two subjects, using indexed terms and free text: "Orbital Apex" and "Orbital Anatomy."

RESULTS

A total of 114 relevant papers were included in this review. Numerous anatomical variations are described in the literature. Variations of the optic canal include duplication (0.64%) and keyhole anomaly (2.65%). Variations in pneumatization of the anterior clinoid process were unilateral in almost 10%, bilateral in 9%, and normal in 72%. A rare variant of the superior orbital fissure (SOF) is Warwick's foramen, which appears as if the lowest portion of the SOF was separated from the main fissure by a transverse bony bridge.

CONCLUSION

The definition of the orbital apex varies in the literature, and further research would most likely identify additional variations. A universal definition reporting these variations and pathology and imaging findings is essential for determining the optimal surgical approach to the orbital apex.

Anatomic Nuances of the Ophthalmic Artery Origin from a Ventral Viewpoint: Considerations and Implications for Endoscopic Endonasal Surgery

BACKGROUND

The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated.

OBJECTIVE

To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective.

METHODS

The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies.

RESULTS

On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm).

CONCLUSION

Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions.

Embryology and anatomical variations of the ophthalmic artery

PURPOSE

The ophthalmic artery (OA) has one of the most complex anatomy and the most fascinating embryological development.

METHODS

The complexity of the embryologic development of the OA resides in the implication of three different embryological systems: the carotid system, the stapedial system, and the ventral pharyngeal system.

RESULTS

This explains very well the numerous variations in origin of the OA and the importance of vascular anastomoses developed with branches of the external carotid artery and with the middle meningeal artery.

CONCLUSION

In this review, authors propose a comprehensive description of different hypotheses on the embryologic development of the OA and, in a second part, explain all anatomical variations and clinical implications of this artery.

Ophthalmic Arteries Arising from the Bilateral Anterior Cerebral Arteries Diagnosed by Three-Dimensional Time-of-Flight Magnetic Resonance Angiography

BACKGROUND

The ophthalmic artery (OA) is a very important branch of the supraclinoid segment of the internal carotid artery. Origination of the OA from the anterior cerebral artery is an extremely rare condition. Being unaware of the origin anomalies of OAs can lead to unfavorable results, especially in cases in which craniofacial surgery or cerebral therapeutic angiography is planned.

CASE DESCRIPTION

An anomalous origin of the ipsilateral OAs from the A1 segments of the bilateral anterior cerebral arteries was detected by three-dimensional time-of-flight magnetic resonance angiography.

CONCLUSIONS

Anomalous origin of the OA from the anterior cerebral artery may be explained by a failure in the caudal migration of the ventral OA. Because of high soft tissue resolution and absence of radiation, three-dimensional time-of-flight magnetic resonance angiography is preferred for detection of orbital and cerebral vascular anomalies.

An update on the variations of the orbital blood supply and hemodynamic

PURPOSE

Several variations of the arterial blood supply of the orbit have been reported over the years. This review is aimed to provide an update focusing on three important issues: (a) variations of the ophthalmic artery origin; (b) contribution of the external carotid artery to the orbital blood supply; (c) orbital hemodynamic.

METHODS

A PubMed and Google search was carried out with the following keywords: ophthalmic artery origin, ophthalmic artery anastomoses and ophthalmic artery anatomy.

RESULTS

The site of origin of the ophthalmic artery displays a limited number of variations. However they are important as they are also associated with course variations. Anastomoses between the ophthalmic artery and the external carotid artery are numerous and many of them can acquire clinical relevance. Records on their anatomic frequency are limited. Orbital hemodynamic variations are a poorly studied subject. Recent investigations in children have unveiled unexpected variability and instability in the way the blood flows through the orbit.

CONCLUSIONS

The orbit shows several possible arterial variations. Some of them have a profound influence on its hemodynamic at least in children. More studies are required to ascertain if the hemodynamic variability observed in children can be pinpointed also in adults.

First insight into the proteome landscape of the porcine short posterior ciliary arteries: Key signalling pathways maintaining physiologic functions

Short posterior ciliary arteries (sPCA) provide the major blood supply to the optic nerve head. Emerging evidence has linked structural and functional anomalies of sPCA to the pathogenesis of several ocular disorders that cause varying degrees of visual loss, particularly anterior ischaemic optic neuropathy and glaucoma. Although the functional relevance of this vascular bed is well-recognized, the proteome of sPCA remains uncharacterized. Since the porcine ocular system closely resembles that of the human's and is increasingly employed in translational ophthalmic research, this study characterized the proteome of porcine sPCA employing the mass spectrometry-based proteomics strategy. A total of 1742 proteins and 10527 peptides were identified in the porcine sPCA. The major biological processes involved in the maintenance of physiological functions of the sPCA included redox and metabolic processes, and cytoskeleton organization. These proteins were further clustered into diverse signalling pathways that regulate vasoactivity of sPCA, namely the tight junction, α- and β-adrenoceptor, 14-3-3, nitric oxide synthase and endothelin-1 -mediated signalling pathways. This study provides the first insight into the complex mechanisms dictating the vast protein repertoire in normal vascular physiology of the porcine sPCA. It is envisioned that our findings will serve as important benchmarks for future studies of sPCA.