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Indications Corridor and Limits of Exposure: The endoscopic endonasal transpterygoid approach (EETPA) provides direct access to the petrous apex, lateral clivus, inferior cavernous sinus compartment, jugular foramen, and infratemporal fossa. 1,2 In the coronal plane, it provides exposure far beyond a traditional sphenoidotomy., Anatomic Essentials Need for Preoperative Planning and Assessment: The pterygoid process of the sphenoid bone forms the junction between the body and greater sphenoid wing before bifurcating because it descends into medial and lateral plates. The key to this exposure lies in the region's bony foramina: the palatovaginal canal, vidian canal, and foramen rotundum. 3., Essentials Steps of the Procedure: After performing a maxillary antrostomy, stepwise exposure of these foramina leads to the pterygopalatine fossa. The sphenopalatine artery is cauterized as it becomes the posterior septal artery at the sphenopalatine foramen, and the maxillary sinus' posterior wall is opened to expose the pterygopalatine fossa. After mobilizing and retracting the contents of the pterygopalatine fossa, the pterygoid process is removed, improving access in the coronal plane. 4., Pitfalls/avoidance of Complications: Vidian neurectomy causes decreased or absent lacrimation. Injury to the maxillary nerve or its branches results in facial, palatal, or odontogenic anesthesia or neuralgia. In addition, the EEPTA precludes the ability to raise an ipsilateral nasal septal flap, making it crucial to plan reconstruction preoperatively. 4,5., Variants and Indications for Their Use: There are 5 variants of the EEPTA: extended pterygopalatine fossa, lateral recess of the sphenoid sinus, petrous apex, infratemporal fossa and petrous carotid artery, and middle and posterior skull base. 5The patient consented to the procedure.Images in the video used with permission as follows: images at 0:33 and 1:15 reused from Bozkurt et al, 3 © Georg Thieme Verlag KG; image at 0:39 from Prosser et al, 5 © John Wiley and Sons; images at 0:54, 9:03, and 9:38 from Kasemsiri et al, 1 © John Wiley and Sons; images at 1:07 and 9:44 from Falcon et al, 2 © John Wiley and Sons; image at 1:15 from Sandu et al, 4 © Springer Nature., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background: The continuous development of microsurgical techniques to treat lesions in and around the optic canal (OC) emphasizes the need for an accurate understanding of the microanatomy of the region., Methods: Forty anatomic specimens were studied, with emphasis on the OC. The sphenoid bone and related structures were decalcified, added to animal gelatin, cut into 1-mm thick slices, and observed through a surgical microscope. The OC was considered the course that contained exclusively the optic nerve (ON) and ophthalmic artery., Results: The mean distance between the medial walls of the OC was 12.2 mm, and the OC had an average length of 12.06 mm. The OC has a horizontal oval shape in the proximal (internal) segment; a round shape in the middle segment; and a vertical oval shape in the distal (external) segment at the orbital cavity. In the middle segment of the OC, the thickest wall of the OC was the lateral (average: 0.68 mm), while the medial, inferior, and superior wall measures had averages of 0.75, 0.40, and 0.39 mm, respectively. The lateral wall of the sphenoid sinus is located under the OC, and the inferior wall of the OC separates both structures. The ophthalmic artery inside the OC was always located under the ON, between the dural sheaths, and had an average diameter of 1.03 mm., Conclusions: The neurovascular structures within the OC vary in size and shape. The anatomic knowledge of the OC and its variations allows better surgical results and minimizes the surgical morbidity., (Copyright © 2021. Published by Elsevier Inc.)

Purpose: The complex relations of the paraclinoid area make the surgical management of the pathology of this region a challenge. The anterior clinoid process (ACP) is an anatomical landmark that hinders the visualization and manipulation of the surrounding neurovascular structures, hence in certain surgical interventions might be necessary to remove it. We reviewed the anatomical relationships that involve the paraclinoid area and detailed the step-by-step techniques of intra and extradural clinoidectomy in cadaveric specimens., Materials and Methods: A literature review was done describing the most relevant anatomic relationships regarding the anterior clinoid process. Extradural and intradural clinoidectomy techniques were performed in six dry bone heads and in ten previously injected cadaverous specimens with colored latex (Sanan et al. in Neurosurgery 45:1267-1274, 1999) and each step of the procedure was recorded using photographic material. Finally, an analysis of the anatomical exposure achieved in each of the techniques used was performed., Results: The main advantage of the intradural clinoidectomy technique is the direct visualization of the neurovascular structures adjacent to the ACP when drilling, at the same time, opening the Sylvian fissure will allow the direct visualization of the ACP variants. The main advantage offered by the extradural technique is that the dura protects adjacent eloquent structures while drilling. Among the disadvantages, it is noted that the same dura that would protect the underlying structures also prevents the direct visualization of these neurovascular structures adjacent to the ACP., Conclusion: We reviewed the anatomy of the paraclinoid area and made a step-by-step description of the technique of the anterior clinoidectomy in its intra- and extradural variants in cadaveric preparations for a better understanding., (© 2021. The Author(s), under exclusive licence to Springer-Verlag France SAS part of Springer Nature.)

Purpose: The sphenoidal artery is considered a component of the complex and dangerous arterial anastomoses of the human orbitocranial region, particularly with the advent of interventional neuroimaging. The objective of this publication was to analyze the various descriptions of the sphenoidal artery in the literature as related to relevant photographs of a dissected arterially injected fetal middle cranial fossa and orbit., Methods: Publications dealing with middle meningeal-ophthalmic arterial anastomoses, focusing on the sphenoidal artery, were reviewed. A relevant dissection of a fetal specimen was analyzed., Results: The literature dealing with the sphenoidal artery is at times not in agreement. The nomenclature and anatomy of its passage through the superior orbital fissure or Hyrtl canal have variable descriptions. Photographs of the skull base of a dissected arterially injected fetal specimen show bilateral prominent orbital branches of the middle meningeal arteries. These branches entered both orbits in a course similar to the diagrammatic representations of the sphenoidal artery, and give rise to several major intraorbital arteries. This study provides the only photographic image in the literature of this variation in a human fetal anatomic dissection., Conclusions: Review of the literature dealing with the sphenoidal artery shows inconsistent nomenclature and conflicting descriptions of its anastomotic connections, and varying evolutionary and embryologic theories. Analysis of the dissected fetal skull base indicates that the sphenoidal artery is not a distinct artery but just a middle meningeal orbital arterial branch, an important component of the complex and dangerous arterial anastomoses of the human orbitocranial region.

Purpose: The goal of this study was to assess the morphological variations, location, and morphometric measurements of the foramen venosum (FV) and analyse its interrelationships with other foramina on cone-beam computed tomography (CBCT) scans., Methods: A total of 269 individual CBCT scans were evaluated retrospectively. The presence or absence of FVs and their diameter, shape, and confluence to foramen ovale were recorded. The distances between anatomic structures and the FV were calculated. Appropriate statistical analysis was performed for the collected data., Results: Of the 269 cases studied, nine were excluded due to duplicate foramina that made statistical analysis difficult. In the 260 evaluated scans, the FV was identified in 190 individuals (73.1%). The incidence was 148 (56.9%) on the right side and 152 (58.5%) on the left side. The FV was present unilaterally in 80 (30.8%) and bilaterally in 110 (42.3%) out of the 260 individuals. The mean maximum diameter of FV was 1.75 ± 1.27 mm, and no significant differences related to gender and age were detected (p < 0.05). The most prevalent foramen shape was the oval type (45.9% on the right side and 40.8% on the left side)., Conclusion: FV is a very frequent anatomical variation. This foramen can exist either bilaterally or unilaterally. No significant differences related to sex, side, or age could be found in the present study. The anatomic characteristics of FV should be considered during interventions in the middle cranial fossa. CBCT imaging with lower radiation doses and thin slices may prove useful before surgical skull-base procedures.

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., (Copyright © 2018 by the Congress of Neurological Surgeons.)

We present a rare case of a vascular anomaly of the sphenoid and temporal bones causing an expandable mass of the temporal region with dependent patient positioning and characteristic osseous changes on imaging. Initial diagnosis considerations included multiple myeloma (MM), fibrous dysplasia (FD), Paget's disease, lymphoma, meningoencephalocele (MEC), and vascular malformation (VaM). VaMs of the head and neck are rare and typically arise in the mandible and maxilla. However, this case demonstrates a unique finding of a VaM of the sphenoid and temporal bones with important radiological features to distinguish the diagnosis of vascular anomaly from other etiologies., (Published by Elsevier Inc.)

Objectives: The anatomic variations of the sphenoid sinus and its relation to the surrounding neurovascular structures are a subject of interest. The purpose of this study was to radiologically assess the frequency of protrusion/dehiscence of key neurovascular landmarks surrounding the Egyptians' sphenoid., Methods: This is a cross-sectional descriptive study of sinonasal computed tomography of the sphenoid sinus in 500 adult Egyptians, conducted at Mansoura University Hospitals; Egypt, over a period of 1 year. Two archives were used for collecting the data; the hard archive and the electronic archive. Variables of interest included the extent of sphenoid sinus pneumatization; intersphenoid septation pattern; protrusion/dehiscence of the internal carotid artery, optic nerve, maxillary nerve, and vidian nerve; and detection of the Onodi cell., Results: Population of this study included 265 women and 235 men. Their ages ranged from 18-68 years. The bilateral sellar-type pneumatization was shown as the most common pneumatization type (96.8%). Pneumatizations of the pterygoid process, anterior clinoid process, and greater wing of the sphenoid were identified in 9.3%, 8.9%, and 31.8% consequently. A single intersphenoid septum was detected in 85.2%, whereas multiple intersphenoid septums were noted in 11.6%. Protrusion of the internal carotid artery, optic nerve, vidian nerve, and maxillary nerve was recorded in 8.5%, 9.1%, 6.6%, and 3.4% consequently, while dehiscence was reported in 7.2%, 15%, 11.9%, and 4.2% consequently as well. Onodi cell was recognized in 18%., Conclusions: This radiologic study highlights significant variations of surgically important anatomic structures related to the sphenoid sinus in Egyptians., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: The knowledge of sinonasal vasculature is inevitable in transnasal neurosurgery. We performed an anatomical study on the sphenopalatine artery from the perspective of skull base procedures., Methodology: To analyse the anatomical landmarks of the sphenopalatine artery, arterial skull corrosion casts (26 head halves) underwent endoscopic transnasal phantom surgery. Furthermore, we performed microsurgical dissection on formaldehyde-fixated cadavers with arterial perfusion (14 head halves) as well as studied Cone Beam CT-scans of anonymised patients and cadavers (115 head sides)., Results: In our cadaveric material, the sphenopalatine foramen is located at the transition of the superior and middle nasal meatus (95.0%) or in the superior nasal meatus (5.0%). It is the main entry point of the branches of the sphenopalatine artery into the nasal cavity. In most cadaveric cases (25.0%), at this level there are 2 branches superiorly and 1 vessel inferiorly to the ethmoid crest. An average of 2.4 vessels leave the sphenopalatine foramen superiorly to the ethmoid crest, 97.8% of them belong to the sphenopalatine arterys posterior septal branches. An average of 2.1 branches leave the sphenopalatine foramen inferiorly to the ethmoid crest; all of them belong to the posterior lateral nasal branches. There are no cases with a single artery at the plane of the sphenopalatine foramen. We describe a triangular bony structure bordering the sphenopalatine foramen anteriorly which is built up by the palatine and ethmoid bone as well as the maxilla. According to the radiographic studies, this triangular prominence is surrounded superiorly by a posterior ethmoid cell (57.4%), the sphenoid sinus (41.7%) or the orbit (0.9%) with a varying contribution of the superior nasal meatus; inferolaterally by the maxillary sinus (98.3%) or the pterygopalatine and infratemporal fossa (1.7%) and inferomedially by the middle nasal meatus. The medial vertex of the bony triangle corresponds to the ethmoid crest of the palatine bone. In transnasal endoscopic surgery, the posterior lateral nasal branches of the sphenopalatine artery appear at the triangle's inferomedial edge, the posterior septal branches emerge at its superior edge., Conclusions: The triangular bony structure is a landmark to find and differentiate the posterior lateral nasal and posterior septal branches of the sphenopalatine artery and to identify the sphenoid sinus.

For a long time, because of its location at the skull base level, the sphenoid bone was rather mysterious as it was too difficult for anatomists to reach and to elucidate its true configuration. The configuration of the sphenoid bone led to confusion regarding its sutures with the other skull bones, its shape, its detailed anatomy, and the vascular and nervous structures that cross it. This article takes the reader on a journey through time and space, charting the evolution of anatomists' comprehension of sphenoid bone morphology from antiquity to its conception as a bone structure in the eighteenth century, and ranging from ancient Greece to modern Italy and France. The journey illustrates that many anatomists have attempted to name and to best describe the structural elements of this polymorphous bone.

Objective: This study aimed to investigate the application of 3-dimensional computed tomography angiography (3D-CTA) for defining cavernous sinus aneurysms and intradural aneurysms involving the internal carotid artery around the anterior clinoid process., Methods: Results from 42 patients with an aneurysm of the internal carotid artery around the anterior clinoid process who underwent 3D-CTA were reviewed and compared with those of observed clinical operations., Results: Among the 42 patients, there was a total of 45 aneurysms of the internal carotid artery around the anterior clinoid process. After surgery, 33 of the 45 aneurysms were confirmed as intradural aneurysms, and the other 12 were confirmed as aneurysms in the cavernous sinus. 3D-CTA imaging of the medial sagittal plane showed that 31 out of 31 (100%) intradural aneurysms of the internal carotid artery were above the virtual line between the inferior border of the anterior clinoid process and the tuberculum sellae, and 12 out of 14 (86%) cavernous sinus aneurysms were below the virtual line (P < 0.0001)., Conclusions: The virtual line between the inferior border of the anterior clinoid process and the tuberculum sellae on 3D-CTA indicates the proximal dural ring of the internal carotid artery. This line helps differentiate cavernous sinus aneurysms from intradural aneurysms involving the internal carotid artery around the anterior clinoid process., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: The middle meningeal artery is in close proximity to the medial aspect of the temporomandibular joint (TMJ). A major potential complication of surgery in the area of the TMJ is possible severance of the middle meningeal artery. An understanding of the relationship of the middle meningeal artery to easily identifiable landmarks lateral to the TMJ can help prevent the complications associated with TMJ surgery. The aim of the present study was to define the location of the middle meningeal artery by relating the distance between the easily identifiable bony landmarks of the articular eminence, petrotympanic fissure, and foramen spinosum., Materials and Methods: Using a cross-sectional study design, we selected dried skulls from the Hamman-Todd skeleton collection at the Cleveland Museum of Natural History that were older than 20 years of age at death. The primary study variables were the distances between the articular eminence and foramen spinosum and the foramen spinosum and petrotympanic fissure. To appropriately analyze the variables, stratifications of age, gender, race, and anatomic location were applied. To measure the relationship between the stratifications and distances, a multivariate analysis of variance test was performed. The statistical results were deemed significant at P < .05., Results: The sample consisted of 354 skulls or a total of 708 complexes. In analyzing the data, we noted that the only stratifications that bore any statistical significance were gender, with P < .0001, and the race-distance correlation, with a P value of .0007., Conclusions: The results of the present study suggest a definite difference in regard to gender on the distance between both sets of anatomic landmarks. Future studies could be tailored to further explore the effect of age on the distance, as a slight correlation was noted in our study., (Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Introduction: The shape of the cavernous segment of the internal carotid artery (CSICA) is various in different people, which makes it difficult to be located and causes a higher possibility of injury in the transsphenoidal approach. Hence, a comprehensive study of the CSICA and a meaningful classification of it are rather helpful to the approach and other operations related to the CSICA., Purpose: Our study aimed to make a comprehensive measurement and classify the CSICA into different types so as to better describe its shape and position., Materials and Methods: Computed tomographic angiography images of 146 internal carotid arteries in individuals (76 males and 70 females) ranging in age from 17 to 78 years (mean, 49.49 y) were reviewed. We measured the distances between the bilateral CSICA at 5 positions in the coronal plane and the angle of the posterior curve segment in the sagittal plane. According to these statistics, we divided the CSICA into different types., Results: The distance between the medial walls of the bilateral internal carotid artery is similar to the previous relevant study. We classified the horizontal segment of the CSICA into 5 types: types 1, 2, 3, 4, and 5. Among the individuals we measured, the proportion of each type is 8.2%, 25.3%, 39.7%, 19.9%, and 6.9%. In addition, the posterior curve segment of the CSICA can be classified into 4 types: types Z, A, S, and O. Among the 292 sides we measured, the proportion of each type is 22.6%, 17.8%, 21.9%, and 37.7%. Furthermore, 80.8% of the people with bilateral sides of type O belonged to type 3 and 72.7% of the people with bilateral sides of type Z belonged to type 2., Conclusions: The detailed classification of the CSICA is helpful to understand its complexity. The classification of the CSICA can guide the surgeons in the transsphenoidal approach to avoid injuring and to simplify the location of the whole CSICA.

Interest in studying the anatomy of the abducent nerve arose from early clinical experience with abducent palsy seen in middle ear infection. Primo Dorello, an Italian anatomist working in Rome in the early 1900s, studied the anatomy of the petroclival region to formulate his own explanation of this pathological entity. His work led to his being credited with the discovery of the canal that bears his name, although this structure had been described 50 years previously by Wenzel Leopold Gruber. Renewed interest in the anatomy of this region arose due to advances in surgical approaches to tumors of the petroclival region and the need to explain the abducent palsies seen in trauma, intracranial hypotension, and aneurysms. The advent of the surgical microscope has allowed more detailed anatomical studies, and numerous articles have been published in the last 2 decades. The current article highlights the historical development of the study of the Dorello canal. A review of the anatomical studies of this structure is provided, followed by a brief overview of clinical considerations.

Alongside the past development of endoscopic sinus surgery, knowledge about the anatomy of the sinuses has become crucial for surgeons. The sphenoid sinus is one of the most variable of all sinuses. Its relations to vital vascular and nervous elements make its approach a challenge for endoscopic surgeons. These relations include the internal carotid artery, the optic nerve, the pituitary gland, the Vidian nerve, and other vascular and nervous elements depending on the size of the sinus. This paper will make a review of these anatomical relations and their importance in endoscopic sphenoid surgery.

Infarction of the orbital bone in patients with sickle cell disease is very rare. The authors report a young boy who presented twice with marked acute proptosis and eyelid swelling of the right eye resulting from infarction in the greater wing of the sphenoid bone accompanied by an orbital subperiosteal collection. The time interval between the 2 attacks was 3 years.

Objective: The purposes of this study were to locate the constant anatomic landmarks, which are very important and helpful for endoscopic surgery and not well described for the pterygopalatine fossa (PPF) surgery via the middle nasal meatus-sphenopalatine foramen approach to establish a safe surgical mode., Methods: Eight cases of adult skull specimens were selected for the simulated surgery. The Messerklinger surgical approach was used under the endoscope. The uncinate process was removed successively, and the anterior ethmoid sinus and posterior ethmoid sinus were opened. The opening of the maxillary sinus was identified and was expanded forward and backward. The ethmoidal crest was found and was used as an anatomic landmark to find the sphenopalatine foramen. The sphenopalatine artery was protected and was used as a guide to enter the PPF region. The sphenopalatine artery was followed conversely to anatomize the blood vessels and nerves in the PPF., Results: It was found that our surgical procedure provides a clear view of the constant anatomic landmark including ethmoidal crest and sphenopalatine foramen. By retrograde dissection, following the sphenopalatine artery, which runs out of the sphenopalatine foramen behind the ethmoidal crest, the internal maxillary artery (IMA) and the branches of the IMA in the PPF were exposed. Posterior to the sphenopalatine artery, the typical Y-shaped structure with the pterygopalatine ganglion as the center was visible when the IMA and its branches were moved downward and outward. The Y structure, which is consisted of the pterygopalatine ganglion, branches of the internal maxillary nerve, vidian nerve, and descending palatine nerve, served as the other anatomic landmark. By following the Y structure, it was easy to locate the pterygoid canal, foramen rotundum, and the infraorbital nerve, and the integrity of the nerve structure could be protected., Conclusion: Endoscopic PPF surgery via the middle nasal meatus-sphenopalatine foramen approach is safe, and the ethmoidal crest, sphenopalatine foramen, and Y structure with the pterygopalatine ganglion in the center are important anatomic landmarks that can be referred to during the surgery.

The goal of this study was the investigation of the arterial blood supply to the maxillary sinus to give clinicians the basis for a better understanding of the origin of vascular complications that can derive from surgical procedures at this level. The study consisted of 30 sinuses from 15 human cadavers with an age range of 59 to 90 years. To define the complex vascularization of the maxillary sinus, the afferent vascular network was injected with liquid latex mixed with red india ink through the external carotid arteries. An intraosseous anastomosis between the dental branch of the posterior superior alveolar artery, also known as alveolar antral artery, and the infraorbital artery was found in 100% of cases. Such an anastomosis seemed to guarantee the blood supply to the sinus membrane, to the periosteal tissues, and especially to the anterior lateral wall of the sinus. Moreover, the gingival branch of the posterior superior alveolar artery was found to anastomose an extraosseous branch of the infraorbital artery in 10 sinuses. The examination of the maxillary sinus also showed a close anatomic relationship among the sinus posterior wall, the descending palatine artery, and the sphenopalatine artery in all 30 sinuses. Small branches deriving from the posterior lateral nasal arteries have been found to perforate the nasal wall laterally and reach the mucosa of the maxillary sinus. A sound knowledge of the maxillary sinus vascularization is essential to prevent vascular complications during surgical operations involving this region.

Objective: The vidian canal, the conduit through the sphenoid bone for the vidian nerve and artery, has become an important landmark in surgical approaches to the cranial base. The objective of this study was to examine the anatomic features of the vidian canal, nerve, and artery, as well as the clinical implications of our findings., Methods: Ten adult cadaveric specimens and 10 dried skulls provided 40 vidian canals for examination with x 3 to x 20 magnification and the endoscope., Results: The paired vidian canals are located in the skull base along the line of fusion of the pterygoid process and body of the sphenoid bone. The canal opens anteriorly into the medial part of the pterygopalatine fossa and posteriorly at the upper part of the anterolateral edge of the foramen lacerum. The vidian nerve, when followed posteriorly, reaches the lateral surface of the anterior genu of the petrous carotid and the anteromedial part of the cavernous sinus where the nerve is continuous with the greater petrosal nerve. The bone surrounding the upper part of 12 of 20 vidian canals protruded into the floor of the sphenoid sinus and one canal had a bony dehiscence that exposed its contents under the sinus mucosa. Nine petrous carotid arteries (45%) gave rise to a vidian artery, all of which anastomosed with the vidian branch of the maxillary artery in the vidian canal or pterygopalatine fossa. The vidian canal can be exposed by opening the floor of the sphenoid sinus, the posterior wall of the maxillary, the posterior part of the lateral wall of the nasal cavity, and the medial part of the floor of the middle fossa., Conclusion: The vidian canal and nerve are important landmarks in accessing the anterior genu of the petrous carotid, anteromedial part of the cavernous sinus, and petrous apex.

The morphogenesis and evolution of the cranium are the result of structural interactions among its components, leading to covariance between traits. Soft and hard tissues exert a reciprocal physical and physiological influence, leading to the final phenotype in terms of both ontogeny and evolution. The middle meningeal vessels, interfacing the brain and the braincase, provide an opportunity to study this network, even in extinct human species. Between and within-species variations of the vascular patterns may be mechanically influenced by the cranial morphology (structural hypothesis) or else by actual physiological responses and adaptations, mostly related to oxygen supply and/or thermoregulation (functional hypothesis). In this analysis, we tested the relationship between neurocranial shape and the general morphology of the traces of the middle meningeal vessels in a modern human population, by using landmark-based geometrical models. Although there are some neurocranial differences between groups with different vascular patterns, they are very small or not statistically significant. Only the depth of the imprints may be more influenced by the endocranial morphology. Even if the neurocranial differences among extinct hominids are definitely larger than those within the modern species, the present analysis suggests that it is unlikely that the differences in vascular patterns among the human species are related only to the effects of different neurocranial geometry. This is rather relevant when the marked development of the meningeal network in Homo sapiens is taken into account, compared with the patterns described for nonmodern human species.

Objectives: Ethmoidal arteries (EAs) can be responsible for severe bleeding. Clinical features of EA bleeding are rather extensive because it can occur within the nasal cavity or in orbital spaces. Furthermore, surgical management of EA bleeding is challenging., Study Design: Retrospective evaluation., Method of Study: Five clinical patients with severe bleeding from EAs and/or epistaxis refractory to sphenopalatine artery closure were included in this work. Careful anatomic dissection of the orbitoethmoidal region was performed in 3 fresh injected heads., Results: Ethmoidal artery management is not uniform because it depends on the rapidity and severity of the bleeding and the chambers within which it happens. Trauma-related bleeding usually requires a lateral canthotomy, whereas in intraoperative bleeding, efforts should be made to directly coagulate the bleeding vessel, even within the orbital fat. Spontaneous epistaxis refractory to sphenopalatine artery closure is to be addressed externally, preferably under endoscopic vision., Conclusions: Ethmoidal artery management differs according to the clinical situation. Elective surgery is advisable for spontaneous epistaxis, whereas emergency treatment, ranging from intraorbital coagulation of the bleeding vessel to lateral canthotomy (when the patient is in a sight-threatening condition), is necessary when the bleeding occurs within orbital spaces. A treatment management algorithm is useful in cases of severe and refractory EA bleeding.

Purpose: There are several vascular vessels that supply the maxillary sinus, such as the posterior superior alveolar artery, the anterior superior alveolar artery, and the infraorbital artery (IOA). These vessels have to be taken into consideration during a sinus augmentation because of the potential risk of bleeding during the procedure. The objective of this investigation was to study variations in maxillary sinus artery connections with the potential surgical effect during a sinus floor elevation by the lateral wall., Materials and Methods: The first part of the study was done in 32 anatomical specimens embedded in 10% formaldehyde solution and aged between 55 and 70 years (mean, 61.3 years). The second part of the study was a radiographic study using computerized tomographic (CT) scan images in 35 randomized patients treated in odontology and maxillofacial surgery departments., Results: Results were recorded for 134 sinuses. In most cases, there was no vessel visible or no vessel present with a diameter less than 0.5 mm after dissection or CT-scan analysis: 120 sinuses (89.5%). In 14 cases (10.5%) there were vessels in the lower two thirds of the anterolateral wall. In 10 sinuses (71.4% of the 14 cases), there was an intraosseous or intrawall artery and in 2 sinuses (14.3%) they were in the intrasinusal position. In 8 of the 14 sinuses (57.1%, about 6% of overall sinuses) the diameter was between 1 and 2.5 mm., Conclusion: Knowledge of the arterial supply is essential for surgical treatment in the sinus area. A CT scan is recommended and the radiologist must be advised to search for intraosseous or extraosseous vessels in the lower two thirds of the maxillary sinus.

Purpose: To present 3 cases of orbital compression syndrome caused by infarction of the greater wing of the sphenoid in patients with sickle cell disease., Methods: Case report and review of the literature., Results: Three patients with sickle cell disease (2 males aged 22 and 16 years, and a 10-year-old girl) who presented with proptosis, limited ocular motility, and chemosis were found to have an infarction of the marrow space of the greater wing of the sphenoid that produced an orbital subperiosteal hemorrhage and exudate demonstrated on MRI. Two patients suffered compressive optic neuropathy; both patients recovered normal optic nerve function. Orbital edema resolved within 48 hours of receiving 1 g methylprednosolone daily. The third patient had normal optic nerve function and his orbital edema improved with methylprednisolone 250 mg/day and intravenous Kefzol over 3 days. In the literature, there are 27 similar cases; 5 were treated surgically and the remainder were managed medically., Conclusions: Patients with sickle cell disease are at risk for orbital compression syndrome secondary to orbital bone infarction, in the setting of vaso-occlusive crises. This diagnosis should be considered when a patient with sickle cell disease presents with headache, proptosis, decreased motility, and/or optic nerve compromise.

Objective: To describe the anatomy of the sphenopalatine foramen (SPF) region and possible anatomical variations., Study Design: Prospective study accomplished from September, 2006, to January, 2007., Methods: The sphenopalatine foramen (SPF) of 61 cadavers were carefully dissected. Presence of the ethmoidal crest, location of sphenopalatine and accessory foramens, and the number of arterial branches emerging through foramens were observed. Data were analyzed in relation to gender, racial group, and symmetry of the cadaver. Prediction of the presence of accessory foramen was evaluated., Results: Mixed race cadavers prevailed in 122 nasal fossae dissected (75% males). Ethmoidal crest was present in 100% of the cadavers, being anterior to the SPF in 98.4% of the cases. The most frequent SPF location was the transition of the middle and superior meatus (86.9%). Mean distance from the SPF and accessory foramen to anterior nasal spine was 6.6 cm and 6.7 cm, respectively. Accessory foramen was present in 9.83% of the cases. A single arterial stem emerged through the SPF in 67.2% of the cases, and 100% through accessory foramens. The prevalence analyses showed no differences that were statistically significant (P > 0.05) between gender and racial group. The symmetry analyses showed a strong conformity (P < 0.01) between nasal fossae in relation to the SPF location. There was no statistically significant conformity between nasal fossae and accessory foramen (P = 0.53). None of the variables of interest presents any statistically significant (P > 0.05) association with the presence of the accessory foramen., Conclusions: There are anatomical variations in the lateral nose wall that should be considered for successful endoscopic surgical treatment of severe epistaxis.

Introduction: The pterygopalatine fossa (PPF) is a narrow space located between the posterior wall of the antrum and the pterygoid plates. Surgical access to the PPF is difficult because of its protected position and its complex neurovascular anatomy. Endonasal approaches using rod lens endoscopes, however, provide better visualization of this area and are associated with less morbidity than external approaches. Our aim was to develop a simple anatomical model using cadaveric specimens injected with intravascular colored silicone to demonstrate the endoscopic anatomy of the PPF. This model could be used for surgical instruction of the transpterygoid approach., Methods: We dissected six PPF in three cadaveric specimens prepared with intravascular injection of colored material using two different injection techniques. An endoscopic endonasal approach, including a wide nasoantral window and removal of the posterior antrum wall, provided access to the PPF., Results: We produced our best anatomical model injecting colored silicone via the common carotid artery. We found that, using an endoscopic approach, a retrograde dissection of the sphenopalatine artery helped to identify the internal maxillary artery (IMA) and its branches. Neural structures were identified deeper to the vascular elements. Notable anatomical landmarks for the endoscopic surgeon are the vidian nerve and its canal that leads to the petrous portion of the internal carotid artery (ICA), and the foramen rotundum, and V2 that leads to Meckel's cave in the middle cranial fossa. These two nerves, vidian and V2, are separated by a pyramidal shaped bone and its apex marks the ICA., Conclusion: Our anatomical model provides the means to learn the endoscopic anatomy of the PPF and may be used for the simulation of surgical techniques. An endoscopic endonasal approach provides adequate exposure to all anatomical structures within the PPF. These structures may be used as landmarks to identify and control deeper neurovascular structures. The significance is that an anatomical model facilitates learning the surgical anatomy and the acquisition of surgical skills. A dissection superficial to the vascular structures preserves the neural elements. These nerves and their bony foramina, such as the vidian nerve and V2, are critical anatomical landmarks to identify and control the ICA at the skull base.

The pterygopalatine fossa (PPF) is a small anatomic region of particular interest in cranial base surgery. Infectious diseases and malignancy may spread through the PPF to contiguous areas as a result of the low resistance offered by the numerous foramina and fissures that surrounds the fossa. We present an anatomic report on the PPF. Twelve sides of six fixed cadaveric heads were dissected through a LeFort I maxillary osteotomy with transantral exposure of the neurovascular content of the PPF. Arterial vascular patterns of the maxillary artery were observed. The pterygopalatine fossa is a deeply located small anatomic region with a rich neurovascular content. The third portion of the maxillary artery in the PPF may demonstrate a variable vascular morphology. A correct understanding and knowledge of the anatomic structures lodged into the PPF, as well as their relationships and functions, remain crucial to minimizing postsurgical morbidity and intraoperative complications.

Introduction: Endonasal surgery represents a radical change in the practice of cranial base surgery and requires the acquisition of new knowledge and surgical skills. The optimal training program for surgeons has not been established., Methods: We reviewed our experience with endonasal cranial base surgery from 1998 to 2006 to develop a training plan for the acquisition of surgical skills. It consists of a modular and incremental approach to endonasal skull base surgery that is designed to train surgeons to function as a team, learn endoscopic skull base anatomy, and develop fundamental endoscopic skills., Results: Stages of training are established for the otolaryngologist-head and neck surgeon and the neurosurgeon that are based on level of technical difficulty, potential risk of vascular and neural injury, and unfamiliar endoscopic anatomy. Mastery of each level is recommended before attempting procedures at a higher level., Conclusions: Standardization of training and the adoption of a modular, incremental training program are expected to facilitate the training of endonasal surgeons in both surgical specialties. Adherence to such a program during the growth phase of endoscopic skull base surgery may decrease the risk of complications as the surgeon's knowledge and surgical expertise develop.

Orbital wall infarction and subperiosteal haematomas are unusual manifestations of sickling disorders. Here we report an 11-year-old girl with sickle cell anaemia having multiple skull infarctions including the orbital bony structures associated with subperiosteal haematomas. The diagnosis was made by MRI, which showed bone marrow changes and associated haemorrhagic collections. The patient was successfully managed without surgical intervention.

KEYPOINTS: Endoscopic ligation of the sphenopalatine artery (ESPAL) has recently become the treatment of choice for refractory epistaxis. This paper reviews the background, indications and potential complications of ESPAL. The main focus of this article is an online video tutorial on the anatomy and surgical technique of ESPAL. Web links lead to video clips of operative steps and therefore this paper should be read in front of a computer with access to the Internet. To study the techniques the links detailed below should be followed. (For computers running RealPlayer software the .wmv extension in each of these links should be replaced with the .rm extension.) * Incision, http://nhsgg.org.uk/content/streams/Figure3.wmv * Flap elevation, http://nhsgg.org.uk/content/streams/Figure4.wmv * Pedicle location, http://www.nhsgg.org.uk/content/streams/Figure5.wmv * Clip application, http://www.nhsgg.org.uk/content/streams/Figure6.wmv.

The greater wing of the human sphenoid bone is pierced by several foramina, which contain, as a main element, the venous anastomoses between the interior of the skull and the extracranial veins. Since data concerning these foramina are scarce in the literature, studies comprising the frequency of occurrence and morphology of the foramina of the greater wing of the human sphenoid bone were undertaken on 100 macerated skulls. We found that the foramen ovale is divided into 2 or 3 components in 4.5% of cases. Moreover, the borders of the foramen ovale in some skulls were irregular and rough. This may suggest, on radiological images, the presence of morbid changes, which might be the sole anatomical variation. Concurrent with the foramen ovale are accessory foramina. The foramen of Vesalius and the cavernous foramen were present in 17% and 33% of cases, respectively. The foramen of Vesalius was always single and the cavernous foramen also occurred in multiple form. The foramen spinosus and the foramen rotundum occurred as permanent elements of the skulls studied. The mean area of the foramina measured, excluding the foramen ovale, was not considerable, which may suggest that they play a minor role in the dynamics of blood circulation in the venous system of the head.

Recent literature has embraced the use of electrosurgery, sphenopalatine vascular clipping, and endoscopy in posterior epistaxis. With the advent of endoscopy, the surgical treatment of posterior epistaxis has shifted from internal maxillary ligation to endoscopic sphenopalatine artery control. This article introduces an endoscopic electrosurgical approach for patients suffering from idiopathic posterior epistaxis that combines one or more of the following methods: endoscopic selective branch cauterization, endoscopic sphenopalatine artery cautery, and endoscopic posterior nasal cauterization. This approach is currently used in a hospital-based community otolaryngology practice and is presented from a Canadian health care perspective (Quebec). This article presents the experience in a series of 17 patients treated during a 35-month period and prospectively followed and discusses the surgical technique, patients' outcome, and the implications of such a practice.

Objective: This prospective randomized trial was designed to compare intranasal endoscopic sphenopalatine artery ligation (ESAL) with conventional nasal packing in the treatment of recurrent epistaxis., Methods: Patients were registered in the study databank following referral for epistaxis control to the otolaryngology service at the University of Alberta. All patients were initially packed using Merocel (Xomed Surgical Products, Jacksonville, FL) nasal dressings bilaterally. Patients were enrolled in the study following failure of Merocel packings. Informed consent was obtained in accordance with the Health Research Ethics Board. The patients were then managed with Vaseline nasal packs or ESAL. Patient demographics, treatment characteristics, number of hospitalization days, and rates of recurrence were recorded prospectively. The total cost of treatment for each patient was calculated., Results: Nineteen patients were enrolled in the study. There was a significant reduction in cost and length of hospitalization of the patients undergoing ESAL compared with the conventional nasal packings. ESAL was also 89% effective in controlling the bleeding and had minimal sequelae or complications. The overall calculated cost of patients undergoing ESAL was dollars 5133 compared with dollars 12213 in the conservative group, resulting in an average saving of dollars 7080 per patient. There was overwhelming patient satisfaction with ESAL compared with nasal packings., Conclusion: ESAL is an excellent, well-tolerated, and cost-effective method of treating recurrent epistaxis.

Purpose: The purposes of this study were to delineate the maxillary artery and its branching arteries and to develop a classification of the various branching patterns by means of serial cadaver dissections of the pterygopalatine fossa region., Materials and Methods: Fifteen Korean adult cadavers were used; 2 sides of each cadaver were examined, for a total of 30 sides. Before dissection of the pterygopalatine region, computed tomography scan was taken of 20 cadaver heads. Sectioned specimens of 9 sides of the cadaver heads in 3.0-mm thickness were made for this study. Then we dissected 21 sides of fresh cadavers under the microscope. In this investigation, we observed branching patterns of the third portion of the maxillary artery, a relationship of the terminal branches of the maxillary artery to the pterygomaxillary junction, and the course of descending palatine artery. Then we classified the branching patterns of the maxillary artery in the pterygopalatine fossa., Results: From the pterygomaxillary junction to the pterygopalatine fossa region, the maxillary artery was usually branched into 5 arteries in the following order: posterior superior alveolar artery, infraorbital artery, artery of the pterygoid canal, descending palatine artery, and sphenopalatine artery. Of 21 cadavers, 18 showed this order (85.7%). There were 2 types of branching patterns of the posterior superior alveolar artery and the infraorbital artery. The average distance from the most inferior point of the pterygomaxillary junction to the posterosuperior alveolar artery, infraorbital artery, and descending palatine artery was 15.2, 32.2, and 24.8 mm, respectively. In most cases (95.2%), the greater and lesser palatine arteries were divided from the short descending palatine artery. According to the contours of the third portion of the maxillary artery, we classified them into 5 types: the "Y" type (19%), "intermediate" type (33.3%), "T" type (23.8%), and "M" type (14.3%)., Conclusion: The results of this investigation show the common patterns of the maxillary artery., (Copyright 2003 American Association of Oral and Maxillofacial Surgeons)

Objective: We describe the detailed microsurgical anatomic features of the clinoid (C5) segment of the internal carotid artery (ICA) and surrounding structures, clarify the anatomic relationships of structures in this region, and emphasize the clinical relevance of these observations. Furthermore, because the nomenclature of the paraclinoid region is confusing and lacks standardization, this report provides a glossary of terms that are commonly used to descibe the anatomic features of the paraclinoid region., Methods: The region surrounding the anterior clinoid process was observed in 70 specimens from 35 formalin-fixed cadaveric heads. Detailed microanatomic dissections were performed in 10 specimens. Histological sections of this region were obtained from the formalin-fixed cadaveric specimens., Results: The clinoid segment of the ICA is the portion that abuts the clinoid process. This portion of the ICA can be directly observed only after removal of the clinoid process. The dura of the cavernous sinus roof separates to enclose the clinoid process. The clinoid segment of the ICA exists only where this separation of dural layers is present. Because the clinoid process does not completely enclose the ICA in most cases, the clinoid segment is shaped more like a wedge than a cylinder. The outer layer of the dura (dura propria) is a thick membrane that fuses with the adventitia of the ICA to form a competent ring that separates the intradural ICA from the extradural ICA. The thin inner membranous layer of the dura loosely surrounds the ICA throughout the entire length of its clinoid segment. The most proximal aspect of this membrane defines the proximal dural ring. The proximal ring is incompetent and admits a variable number of veins from the cavernous plexus that accompany the ICA throughout its clinoid segment., Conclusion: The narrow space between the inner dural layer and the clinoid ICA is continuous with the cavernous sinus via an incompetent proximal dural ring. This space between the clinoid ICA and the inner dural layer contains a variable number of veins that directly communicate with the cavernous plexus. Given the inconstancy of the venous plexus surrounding the clinoid ICA, we think that categorical labeling of the clinoid ICA as intracavernous or extracavernous cannot be justified.

Vascular complication of transsphenoidal surgery can lead to mortality and serious morbidity. In a series of 3,061 transsphenoidal operations for pituitary disease, 24 such complications were encountered, seven of which were fatal. The anatomic substrate for such complications is discussed, along with technical aspects of surgery and other methods for the avoidance of vascular complications.

Angiography with selective embolization has become an accepted method of treating posterior epistaxis that is not controlled with conservative measures. The authors reviewed 112 cases of patients who had received selective angiographic embolization for refractory epistaxis from January 1990 to December 1995. There were 114 embolizations over this 5-year period. The immediate success rate was 93%, with long-term success achieved in 88% of patients. The overall complication rate was 17%, with the long-term morbidity rate less than 1%. Selective angiographic embolization is a safe and effective method that should be considered in the treatment of refractory epistaxis.

Surgical interventions on the infratemporal fossa require an accurate knowledge of the surgical anatomy. Thirty-four adult human skulls were examined and measurements made of the distance between the zygomatic arch and the root of the lateral pterygoid plate. The distance between the central part of the lateral and medial pterygoid plates was also measured. The first measurement represents the distance of the foramen ovale from the zygoma; the average being 38.2 mm. The average distance between the pterygoid plates is 9.6 mm. Addition of these two measurements represents the distance of the lateral wall of the nasopharynx from the zygoma and the average is 47.8 mm. Together with the knowledge of the arrangement of the muscle layers and the nerves and vessels in this region, this information has proved useful in the surgery of the area.

Foramen Vesalius is known to be an inconstant foramen, which appears in the anteriomedial side of the foramen ovale. The foramen Vesalius is classified into the open type and the closed type. We studied the frequencies and the types of foramen Vesalius in Japanese by examining 20 juvenile skulls from 3 months to 8 years old and 400 adult skulls from 18 to 91 years old. Of the 20 juvenile skulls, 11 skulls (55.00%) had foramen Vesalius. Of the 400 adult skulls, 87 skulls (21.75%) had foramen Vesalius; 69 (21.50%) in 321 male and 18 (22.78%) in 79 female skulls. No remarkable differences were observed in the ratio between the male and the female, and between the left side and the right side. Among the 69 adult male skulls, the foramen Vesalius was bilateral in 52 skulls (75.36%) and unilateral in 17 (24.64%); among the 18 adult female skulls, it was bilateral in 13 (72.22%) and unilateral in 5 (27.78%). The ratio of the closed type was slightly higher than that of the open type in both sexes and in both sides; however, no remarkable differences were observed. The skulls with one foramen Vesalius were most frequent; those with two followed it and those with 3 foramen Vesalius were least frequent. No remarkable differences were observed in the number of foramen Vesalius between the sexes and the sides.

Purpose: To define the role of angiography and embolization in the treatment of patients who have arterial injuries during transsphenoidal surgery., Methods: We retrospectively studied the arterial hemorrhagic complications, their management, and the clinical outcomes that occurred in 21 of the more than 1800 patients who had transsphenoidal surgery for pituitary adenomas., Results: Of the 21 patients who had complications, 17 had internal carotid injuries and four had injuries of the sphenopalatine artery. Angiography was performed in 18 patients. Bleeding occurred and was controlled during surgery in 16 cases. Delayed epistaxis occurred in 10 patients, including five whose surgery was uneventful. After internal carotid injury, the most frequent angiographic findings were carotid occlusion (eight patients), stenosis (five patients), and false aneurysms (three patients). Internal carotid balloon occlusion was performed in five patients. No rebleeding occurred in patients who had complete carotid occlusion either from surgical packing or balloon embolization. Two of the patients who had carotid stenosis after surgical packing had delayed epistaxis necessitating balloon occlusion. Injuries to the sphenopalatine artery were successfully treated by surgery (one patient) or by endovascular treatment (three patients) without complication. Three deaths and five permanent deficits were directly related to the arterial injury or its treatment., Conclusion: Profuse bleeding during and after transsphenoidal surgery should be investigated by angiography. Lesions of the sphenopalatine arteries are effectively treated by embolization. Internal carotid injuries are best treated by carotid infusion to prevent life-threatening epistaxis.

The management of nasal septal perforation remains unsatisfactory. Various operative techniques have been described, with modest success. A novel method for repair of septal perforations up to 2.6 cm in diameter was investigated. A double layer closure of nasal septal perforation was designed, one with the cartilage and the other by a flap based on the anterior septal branches of the sphenopalatine artery. Fourteen patients have been operated upon. The current analysis reveals a success rate of 13 patients (93%) who had complete closure and one patient (7%) with incomplete closure. The operative techniques and results are reported here.

50 meningohypophyseal trunks of the intracavernous internal carotid artery were studied in 25 human cadavers. Special attention was given to the main variations of branching patterns of this trunk. The dorsal meningeal arteries were found in all cases and three typical variations were observed in their origins and courses: a prominent medial branch (52%), a bifurcating type (38%) or a single lateral branch was present (10%). The tentorial artery of Bernasconi-Cassinari arised as a single branch in 64% of the cases, while in 36% two or more branches took a direct origin from the main trunk. The inferior hypophyseal artery was prominent in 82% of the cases. The inferolateral trunk had a common origin with the meningohypophyseal trunk in 8% of our dissections. A large number of anastomoses between these vessels was observed. As a number of tumorous and vascular pathologies, which can be treated with microsurgical techniques, take their origin from the cavernous sinus, the knowledge of the smaller vessels arising from the intracavernous internal carotid artery as well as their main variations is important.

A young boy presented with a symptomatic aneurysmal bone cyst of the left great wing of the sphenoid bone. Arterial embolization had failed to produce thrombosis, and the lesion could not be resected surgically. Direct intraoperative sclerotherapy resulted in immediate thrombosis of 80% of the volume of the vascular malformation with no progression of symptoms. Two years later, the symptoms had completely resolved, and CT scans showed total ossification of the lesion.