Orbitozygomatic Approach Research Articles

Minimally invasive orbito-zygomatic access for cranio-orbital hyperostotic meningiomas. Case report

Application into clinical practice of a minimally invasive surgical approach to the removal of hyperostotic cranioorbital meningiomas. This publication is based on the analysis of a clinical case of 49-year-old woman with exophthalmos, and the absence of neurological deficits. A non-standard approach to remove a cranio-orbital hyperostotic meningioma through a minimally invasive orbito-zygomatic approach was used. The main principle of proposed surgical approach was to remove first the hyperostosis, followed by the areas of dura mater involved by the tumor, according to the "outside-in" principle. According to the intraoperative process and the results of MRI control, it was possible to achieve total removal of both the affected dura mater and the hyperostotic lesion. The minimally invasive transorbital approach opens a wide corridor for surgery of the para and retroorbital space and allows using the "outside-in" method, to remove not only hyperostosis but also the area of damage to the dura mater.

Primary intraorbital inflammatory lumpy lesion: A rare case report.

Eosinophilic angiocentric fibrosis (EAF) is considered to be a kind of benign IgG4-related disease, and it is more often found in the nasal cavity. We present a pretty rare case of orbital EAF that is unlike any other reported case for this case is an IgG4 negative orbital EAF and successfully treated by the fronto orbitozygomatic approach surgery. This is a 68-year-old man from a rural area of Inner Mongolia Autonomous Region, went to our hospital for a 2-month history of vision loss with a local hospital orbital computer tomography which showed that there was a lesion in his left orbit. The inspection of the patient revealed that the patient left eye was protruding outward and the left eyelid unable to complete open or close. And his left eyeball movement had difficulty in all directions. Postoperative pathology diagnosed that this was a case of IgG4-negative EAF case. Orbital EAF. Surgical radical resection and postoperative glucocorticoid therapy. After surgery, the left eye vision of this patient increased to 0.6 tested in the standard logarithmic visual acuity chart. And his left eyeball movement dysfunction and eyeball outward protruding get a partially relief. EAF occurring in the orbit is a very rare disease and immunohistochemical results of EAF can be IgG4 negative.

360° around the orbit: key surgical anatomy of the microsurgical and endoscopic cranio-orbital and orbitocranial approaches.

Several pathologies either invade or arise within the orbit. These include meningiomas, schwannomas, and cavernous hemangiomas among others. Although several studies describing various approaches to the orbit are available, no study describes all cranio-orbital and orbitocranial approaches with clear, surgically oriented anatomical descriptions. As such, this study aimed to provide a comprehensive guide to the microsurgical and endoscopic approaches to and through the orbit. Six formalin-fixed, latex-injected cadaveric head specimens were dissected in the surgical anatomy laboratory at the authors' institution. In each specimen, the following approaches were modularly performed: endoscopic transorbital approaches (ETOAs), including a lateral transorbital approach and a superior eyelid crease approach; endoscopic endonasal approaches (EEAs), including those to the medial orbit and optic canal; and transcranial approaches, including a supraorbital approach, a fronto-orbital approach, and a 3-piece orbito-zygomatic approach. Each pertinent step was 3D photograph-documented with macroscopic and endoscopic techniques as previously described. Endoscopic endonasal approaches to the orbit afforded excellent access to the medial orbit and medial optic canal. Regarding ETOAs, the lateral transorbital approach afforded excellent access to the floor of the middle fossa and, once the lateral orbital rim was removed, the cavernous sinus could be dissected and the petrous apex drilled. The superior eyelid approach provides excellent access to the anterior cranial fossa just superior to the orbit, as well as the dura of the lesser wing of the sphenoid. Craniotomy-based approaches provided excellent access to the anterior and middle cranial fossa and the cavernous sinus, except the supraorbital approach had limited access to the middle fossa. This study outlines the essential surgical steps for major cranio-orbital and orbitocranial approaches. Endoscopic endonasal approaches offer direct medial access, potentially providing bilateral exposure to optic canals. ETOAs serve as both orbital access and as a corridor to surrounding regions. Cranio-orbital approaches follow a lateral-to-medial, superior-to-inferior trajectory, progressively allowing removal of protective bony structures for proportional orbit access.

Anterolateral keyhole transorbital routes to the skull base: a comparative anatomical study.

Although keyhole transorbital approaches are gaining traction, their indications have not been adequately studied comparatively. In this study the authors have defined them also as transwing approaches-meaning that they use the different facies of the sphenoid wing for cranial entry-and sought to compare the four major ones: 1) lateral orbitocraniotomy through a lateral canthal incision (LatOrb); 2) modified orbitozygomatic approach through a palpebral incision (ModOzPalp); 3) modified orbitozygomatic approach through an eyebrow incision (ModOzEyB); and 4) supraorbital craniotomy through an eyebrow incision (SupraOrb), coupled with its expanded version (SupraTransOrb). Cadaveric dissections were performed at the neuroanatomy lab. To delineate the skull base exposure, four formalin-fixed heads were used, with two sides dedicated to each approach. The outer limits were assessed via image guidance and were mapped and illustrated accordingly. A fifth head was dissected purely endoscopically, just to facilitate an overview of the transwing concept. Qualitative features were also rigorously examined. The LatOrb proves to be more versatile in the middle cranial fossa (MCF), whereas the anterior cranial fossa (ACF) exposure is limited to a small area above the sphenoid ridge. An anterior clinoidectomy is possible; however, the exposure of the roof of the optic canal is suboptimal. The ModOzPalp adequately exposes both the ACF and MCF. Its lateral trajectory allows the inferior to superior view, yet there is restricted access to the medial anterior skull base (olfactory groove). The ModOzEyB also provides extensive exposure of the ACF and MCF, but has a more superior to inferior trajectory compared to the ModOzPalp, making it more appropriate for pathology reaching the medial anterior skull base or even the contralateral side. The anterior clinoidectomy is performed with improved visualization of the optic canal. The SupraOrb provides mainly anterior cranial base exposure, with minimal middle fossa. An anterior clinoidectomy can be performed, but without any direct observation of the superior orbital fissure. Some MCF access can be accomplished if the lateral sphenoid wing is drilled inferiorly, leading to its highly versatile variant, the SupraTransOrb. All the aforementioned approaches use the sphenoid wing as skull base corridor from a specific orientation point; hence these are designated as transwing approaches. Their peculiarities mandate careful case selection for the effective and safe completion of the surgical goals.

Surgical Simulation Using a Three-Dimensional Printer

3D printers have been applied in bone-based surgeries, including craniofacial, plastic, oral, and orthopedic surgeries. The improved capabilities of diagnostic imaging equipment and 3D printers have enabled the development of more precise models, and research on surgical simulations and training in the field of neurosurgery is increasing. This review outlines the use of 3D printers in neurosurgery at our institution in terms of modeling methods and surgical simulations. Modeling with the powder-sticking lamination method using plaster as the material allows drilling, which is a surgical procedure. Therefore, it is useful for simulating skull base tumors, such as petrosectomy in a combined transpetrosal approach or anterior clinoidectomy in an orbitozygomatic approach. The color coding of each part of the model facilitates anatomical understanding, and meshed tumor modeling allows deep translucency. As shown above, the 3D printer's modeling ingenuity allows for useful surgical simulations for each case.

Clinical application of a three-dimensional-printed model in the treatment of intracranial and extracranial communicating tumors: a pilot study.

Surgical management for intracranial and extracranial communicating tumors is difficult due to the complex anatomical structures. Therefore, assisting methods are urgently needed. Accordingly, this study aimed to investigate the utility of a three-dimensional (3D)-printed model in the treatment of intracranial and extracranial communicating tumors as well as its applicability in surgical planning and resident education. Individualized 3D-printed models were created for eight patients with intracranial and extracranial communicating tumors. Based on these 3D-printed models, a comprehensive surgical plan was made for each patient, after which the patients underwent surgery. The clinicopathological data of patients were collected and retrospectively analyzed to determine surgical outcomes. To examine the educational capability of the 3D-printed models, specialists and resident doctors were invited to review three of these cases and then rate the clinical utility of the models using a questionnaire. The 3D-printed models accurately replicated anatomical structures, including the tumor, surrounding structures, and the skull. Based on these models, customized surgical approaches, including the orbitozygomatic approach and transcervical approach, were designed for the patients. Although parameters such as operation time and blood loss varied among the patients, satisfactory surgical outcomes were achieved, with only one patient developing a postoperative complication. Regarding the educational applicability of the 3D-printed model, the mean agreement for all eight questionnaire items was above six (seven being complete agreement). Moreover, no significant difference was noted in the agreement scores between specialists and residents. The results revealed that 3D-printed models have good structural accuracy and are potentially beneficial in developing surgical approaches and educating residents. Further research is needed to test the true applicability of these models in the treatment of intracranial and extracranial communicating tumors.

Modified orbitozygomatic craniotomy with a single burr hole in the alternative sphenoid ridge keyhole

BackgroundOne-piece modified orbitozygomatic approach (OZA) is an extended version of the pterional approach that also includes orbital walls and frontal process of the zygomatic bone. For this craniotomy one burr hole must be placed in MacCarty keyhole and another - in the temporal region. ObjectiveTo develop a technique of the one-piece modified OZA with single a burr hole in the alternative sphenoid ridge keyhole that allows access to orbit, anterior cranial fossa and middle cranial fossa and apply it intraoperatively. MethodsA single human head specimen was used. The dissection was performed using standard surgical instruments high-speed Stryker drill. Every stage of the approach was photographed. We also report a surgical case of a patient with orbital cavernous hemangioma that was resected using the described technique. ResultsThe technique of the one-piece modified OZA with a single burr hole in the alternative sphenoid ridge keyhole is described, and its advantages and limitations are analyzed. The technique is used to totally resect an orbital cavernous hemangioma with good functional and cosmetic result. ConclusionModified OZA with a single burr hole in the sphenoid ridge keyhole is possible and may be an alternative to the classic technique. The advantages of this variation are the placement of just one burr hole and the preservation of a larger portion of the orbital roof. The latter facilitates better bone reconstruction and better cosmetic outcome. Disadvantages are the difficulty of identifying the location of the sphenoid ridge keyhole and risk of damaging the dura.

How I do it: neuromonitoring-guided clipping of high-riding basilar tip aneurysm.

Clipping of basilar tip aneurysms presents unique challenges due to the risk of perforator compromise and subsequent disabling stroke. Herein, we describe the correct trajectory of the clip applier to clip basilar tip aneurysms through an orbitozygomatic approach to prevent perforator injury and discuss management of intraoperative neuromonitoring changes. We anticipate that this video and illustration will aid surgeons as they treat complex wide-necked basilar tip aneurysms with microsurgical clipping.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Frontotemporal and Orbitozygomatic Craniotomies.

Introduction Although many neuroanatomic atlases have been published, few have detailed complex cranial approaches and pertinent anatomic considerations in a stepwise fashion intended for rapid comprehension by neurosurgery students, residents, and fellows. Methods Five sides of formalin-fixed latex-injected specimens were dissected under microscopic magnification. The frontotemporal and orbitozygomatic approaches were performed by neurosurgical residents and fellows at different training levels with limited previous experience in anatomical dissection mentored by the senior authors (M.P.C. and M.J.L.). Meticulous surgical anatomic dissections were performed until sufficient visual and technical completion was attained, with parameters of effectively demonstrating key surgical steps for educational training purposes. Following the completion of dissection and three-dimensional photography, illustrative case examples were reviewed to demonstrate the relative benefits and optimal applications of each approach. Results The frontotemporal and orbitozygomatic approaches afford excellent access to anterior and middle skull base pathologies, as well as the exposure of the infratemporal fossa. Key considerations include head positioning, skin incision, scalp retraction, fat pad dissection and facial nerve protection, true or false MacCarty keyhole fashioning, sphenoid wing drilling and anterior clinoidectomy, completion of the craniotomy and accessory orbital osteotomy cuts, dural opening, and intradural neurovascular access. Conclusion The frontotemporal and orbitozygomatic approaches are core craniotomies that offer distinct advantages for complex cranial operations. Learning and internalizing their key steps and nuanced applications in a clinical context is critical for trainees of many levels. The orbitozygomatic craniotomy in particular is a versatile but challenging approach; operative-style laboratory dissection is an essential component of its mastery and one that will be powerfully enhanced by the current work.

Experience and Balance: Long-Term Trends in Preferred Skull Base Approach for a Case Series of Cavernous Malformation Resections.

Skull base approaches are a foundation of modern cerebrovascular surgery; however, their application over time has varied. To assess trends in skull base approach selection for cavernous malformation (CM) resection. This is a retrospective case series of all first-time CM resections by a single surgeon from 1997 to 2021. Cases were classified by craniotomy and approach. Four sets of common comparator skull base approaches were identified by coauthor consensus: pterional and orbitozygomatic; retrosigmoid, extended retrosigmoid (xRS), and far-lateral; suboccipital and torcular; and trans-cerebellar peduncle (MCP) and transcerebellopontine angle. Counts were binned by 5-year or 10-year clusters for descriptive statistical assessment of temporal trends. In total, 372 primary CM resections met the study criteria and were included. Orbitozygomatic approach use increased during the second 5-year period, after which the pterional approach rapidly became and remained the preferred approach. During the first two 5-year periods, the far-lateral approach was preferred to the retrosigmoid and xRS approaches, but the xRS approach grew in popularity and accounted for >50% of operations in this comparator group. Trans-MCP use compared with the transcerebellopontine angle approach closely mirrored the change in xRS use. The midline suboccipital approach accounted for a larger proportion (range, 62%-88%) of cases than the torcular approach (range, 12%-38%) across all periods. The xRS and trans-MCP approaches have been increasingly used over time, while the orbitozygomatic and far-lateral approaches have become less common. These trends seem to reflect versatility, efficiency, and safety of these techniques.

Standard Orbitozygomatic Craniotomy versus Mini Orbitozygomatic Craniotomy via an Eyebrow Incision for Microsurgical Treatment of Anterior Communicating Artery Aneurysms.

Background Skull base approaches are utilized to improve microsurgical treatment of cerebral aneurysms. Advantages include early proximal and distal control, increased visualization, and minimal brain retraction. Orbitozygomatic (OZ) craniotomies via pterional incision are commonly used for the treatment of anterior communicating artery (ACoA) aneurysms. A smaller, less invasive OZ craniotomy performed through an eyebrow incision may provide several advantages over a standard OZ approach. Objective We compare surgical outcomes of the standard and eyebrow OZ for the treatment of ACoA aneurysms. Design All patients who underwent microsurgical treatment for ACoA aneurysms by a single surgeon over an 8-year period were included in this retrospective analysis. Patient demographics and clinical data were collected. Participants Thirty-seven consecutive patients were identified, with 15 receiving eyebrow OZ and 22 receiving standard OZ. Main Outcome Measures Data were collected on patient demographics, pathology, intraoperative and perioperative data, and 30-day morbidity. Results A total of 100% of the eyebrow OZ group and 95.5% of the standard OZ group had complete aneurysmal occlusion. Four eyebrow OZ and six standard OZ patients had an intraoperative rupture. All were managed without complication. Two eyebrow OZ and one standard OZ patient died within 30 days of surgery. No patients in either group had aneurysm recurrence, required retreatment, or were limited intraoperatively by exposure. Conclusions The OZ approach via an eyebrow incision has similar outcomes to a standard OZ approach and is a safe option for the treatment of ACoA aneurysms.

Cavernous Malformations: What They Have Taught Us.

Cavernous Malformations: What They Have Taught Us.

Topographic anatomy of two-piece orbitozygomatic, modified orbitozygomatic and transzygomatic approaches: A comparative analysis of neurosurgical options

Aim to measure and compare the vertical and horizontal angles of attack on different intracranial surgical targets provided by the transzygomatic, modified orbitozygomatic and classic two-piece orbitozygomatic approaches, to determine the most optimal approaches to different surgical targets.
 Material and methods. The study was conducted on 8 sides of en bloc specimens of human head and neck. The marking was performed with BrainLAB Kolibri navigational station (Germany) to highlight the surgical landmarks and measure the angles. The dissection was started macroscopically with standard instruments and photographic fixation of every stage of the approach. The craniotomy was performed with Stryker high speed drill (USA). After that, the microscopic stage was carried out with the ZEISS OPMI Vario/S88 surgical microscope (Germany). On each side, the following steps were completed: soft tissues dissection, cutting the zygomatic arch, fronto-temporal craniotomy, orbitozygomatic osteotomy, opening of the dura mater and dissection of structures of the cranial base, measurement of angles of attack with their apex located on skull base structures
 Results. The angles of attack on different intracranial surgical targets were measured and compared for two-piece orbitozygomatic, modified orbitozygomatic and transzygomatic approaches.
 Conclusion. The two-piece orbitozygomatic craniotomy is the most universal and optimal to approach the basilar artery bifurcation and lesions located in both anterior and middle cranial fossae. However, to minimize the surgical trauma and the risks of complications when exposing exclusively anterior cranial fossa, the modified orbitozygomatic approach is more adequate. When the lesion is small and located exclusively in middle cranial fossa, performing the transzygomatic approach is recommended.

Suprasellar Tumor-Craniotomy

Surgical procedures for pediatric suprasellar tumors include craniotomy and nasal surgery. Craniotomies are increasingly performed with a microscope, exoscope, and endoscope, while nasal surgery is performed mainly with endoscopes. In some cases, craniotomy and nasal surgery are performed together. This article describes craniotomy. Due to its large surgical field, craniotomy is often chosen for large tumors in the suprasellar region, tumors located above the optic chiasm and optic nerve, tumors extending laterally, and hypervascularized tumors. It is the surgical technique of choice for many neurosurgeons because they are familiar with it. Craniotomies include bilateral frontal and frontotemporal craniotomies. The interhemispheric and subfrontal approaches involve bilateral frontal craniotomy, pterional approach, orbitozygomatic approach, subtemporal approach using temporal-occipital craniotomy, and transpetrosal transtentorial approach using temporal-occipital-suboccipital craniotomy. The approach was selected based on the direction of tumor extension and relationship between the tumor and optic nerve, optic chiasm, and blood vessels. This paper describes the frequently used interhemispheric and pterional approaches based on our experience.

Pituitary Stalk Hemangioblastoma: Complete Resection through Orbitozygomatic Approach with Extradural Anterior Clinoidectomy.

Background Pituitary stalk hemangioblastomas (PSHBLs) are rare vascular tumors and their surgical removal is challenging due to the proximity with several fundamental anatomic structures including the pituitary stalk, third ventricle, hypothalamus, and optic pathways. To date, only few descriptions of transcranial and transsphenoidal approaches for PSHBLs have been reported in the literature and none in video, with suboptimal outcomes in terms of pituitary function preservation. Here, we describe the use of orbitozygomatic (OZ) craniotomy with extradural anterior clinoidectomy (EAC) for the removal of a PSHBL with preservation of the pituitary stalk. Case Description A 60-year-old woman with a sporadic symptomatic HBL of the pituitary stalk, with the typical features of avid contrast enhancement on T1- and flow voids on T2-weighted magnetic resonance imaging (MRI) images, underwent a right OZ craniotomy with EAC. The choice of the approach was guided by the necessity of exposing the floor of the 3rd ventricle and infundibulum, where the origin of the pituitary stalk is better appreciated and preserved, without brain retraction. EAC was deemed important due to the necessity of widening the right carotico-oculomotor and opticocarotid triangles and gaining access to the ophthalmic segment of the internal carotid artery, origin of the superior hypophyseal artery, and the tumor supply. The postoperative MRI confirmed gross tumor removal with preservation of the pituitary stalk and no tumor recurrence after 2 years of follow-up. Conclusion OZ craniotomy coupled with EAC facilitates surgical removal of PSHBLs thus augmenting the chances of pituitary function preservation. The link to the video can be found at https://youtu.be/hH65W937RGY .

Quantitative Anatomic Comparison of Endoscopic Transnasal and Microsurgical Transcranial Approaches to the Anterior Cranial Fossa.

Several microsurgical transcranial approaches (MTAs) and endoscopic transnasal approaches (EEAs) to the anterior cranial fossa (ACF) have been described. To provide a preclinical, quantitative, anatomic, comparative analysis of surgical approaches to the ACF. Five alcohol-fixed specimens underwent high-resolution computed tomography. The following approaches were performed on each specimen: EEAs (transcribriform, transtuberculum, and transplanum), anterior MTAs (transfrontal sinus interhemispheric, frontobasal interhemispheric, and subfrontal with unilateral and bilateral frontal craniotomy), and anterolateral MTAs (supraorbital, minipterional, pterional, and frontotemporal orbitozygomatic approach). An optic neuronavigation system and dedicated software (ApproachViewer, part of GTx-Eyes II-UHN) were used to quantify the working volume of each approach and extrapolate the exposure of different ACF regions. Mixed linear models with random intercepts were used for statistical analyses. EEAs offer a large and direct route to the midline region of ACF, whose most anterior structures (ie, crista galli, cribriform plate, and ethmoidal roof) are also well exposed by anterior MTAs, whereas deeper ones (ie, planum sphenoidale and tuberculum sellae) are also well exposed by anterolateral MTAs. The orbital roof region is exposed by both anterolateral and lateral MTAs. The posterolateral region (ie, sphenoid wing and optic canal) is well exposed by anterolateral MTAs. Anterior and anterolateral MTAs play a pivotal role in the exposure of most anterior and posterolateral ACF regions, respectively, whereas midline regions are well exposed by EEAs. Furthermore, certain anterolateral approaches may be most useful when involvement of the optic canal and nerves involvement are suspected.

Dolenc's Approach:Anterior Clinoidectomy and Extradural Approach to Cavernous Sinus

The combined epidural and subdural approach pioneered by Dolenc allows opening of the lateral wall of the cavernous sinus(CS)to treat various pathologies such as tumors and aneurysms in the cavernous, para-cavernous, and central skull base regions. The Dolenc's approach is occasionally performed with the orbitozygomatic approach(OZA), which enables us to look up highly located lesions. We prefer the two-piece method when performing OZA: it involves removing the orbitozygomatic bar separately after frontotemporal craniotomy. Dolenc's approach requires dividing the meningo-orbital band and opening the superior orbital fissure to expose the junction between the dura propria of the temporal lobe and inner membrane of the CS, which separates the neurovascular structures and the venous plexus inside. Peeling of the dura propria from the inner membrane is continued until the anterior clinoid process is exposed epidurally. Extradural clinoidectomy and optic canal opening are then performed. After the epidural procedures, intradural procedures are also performed. The falciform ligament and the distal dural ring are incised to mobilize the optic nerve and the internal carotid artery. The tentorium is incised along the anterior petroclinoid ligament. Dolenc's approach allows extradural retraction of the temporal lobe, which provides a surgical corridor to the retro-carotid space and the inter-peduncular cistern through the opened anterior part of the CS.

Microsurgical Management of Complex Hypothalamic Hamartomas in the Era of Minimally Invasive Therapy: A Case Series and Narrative Review

There has been a paradigm shift in the management of hypothalamic hamartoma (HH) from traditional microsurgical techniques to less invasive alternatives. However, large and extensive HH may fail to respond to these therapies, necessitating craniotomies. All patients who underwent microsurgical resection of a complex HH by the 2 senior authors from 2011 to 2021 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, and outcome data were recorded. Eight patients (mean age, 7 years) were included. Two had failed previous treatments. All 7 presented with gelastic seizures and cognitive dysfunction, 6 showed central precocious puberty, and 3 had behavioral problems. The mean lesion size was 21.6 mm and all had interpeduncular extension, 5 had intraventricular extension (Delalande type I, 3; type III, 4; type IV, 1). A frontotemporal orbitozygomatic approach with optic nerve decompression was used in all patients, supplemented by another approach in 3 (endoscopic transventricular, 3; transcallosal, 1). Gross total resection was achieved in 6 patients and subtotal resection in 2. Transient complications occurred in 3 patients (37.5%): self-limited sodium imbalance (n= 3), subdural hygroma (n= 2). Permanent complications occurred in 2 patients (25%): perforator infarct (n= 1) and short-term memory loss (n= 1). All patients experienced seizure resolution with preserved hypothalamic-pituitary axis function. After a mean follow-up of 41 months (range, 2-66 months), 7 patients remained seizure free, and 1 had rare seizures. Cognitive and behavioral symptoms improved in all patients. For large HH with interpeduncular extension, microsurgery via the frontotemporal orbitozygomatic approach is a safe and highly effective treatment modality.

Topographical Anatomy of the Superficial Temporal Artery.

To describe in detail the gross anatomy of the superficial temporal artery (STA), its course and branches, its relationships with the branches of the facial nerve, and certain anatomical and surgical landmarks to preserve these structures in daily neurosurgical practice, and to use the STA during revascularization surgery. This cadaveric study was conducted on 16 cadaver heads bilaterally, in which 32 silicon/latex-injected STAs were dissected using a microdissection technique in a neuroanatomy laboratory. The distances between the facial nerve, tragus, STA, superficial temporal vein (STV), and imaginary lines created between important anatomical landmarks were measured. The curvilinear lengths of STA and STV were also measured. The average distances of the most posteriorly located branch of the facial nerve to the frontal region and the tragus at the midpoint of zygoma in the horizontal plane, at the superior border of the zygoma and at the level of the superior border of the parotid gland, were measured as 25.39, 29.84, and 15.56 mm, respectively. The average distance directly measured between the tragus and STA was 39.29 mm, and that between the tragus and STV was 20.26 mm. The average curvilinear lengths of the frontal and parietal branches of STA were 97.63 and 96.45 mm, respectively. Understanding the clinical anatomy of the STA and its branches and its relationships with other structures is of critical importance for a successful and noncomplicated surgery. Our findings will be useful not only for surgical approaches such as pterional craniotomy and orbitozygomatic approaches but also for cerebral revascularization.

Management of Wide-Necked Basilar tip Aneurysms.

While the frequency of direct surgery for basilar tip aneurysms is decreasing, the need for safe and effective surgical treatments for difficult-to-treat aneurysms, including large or wide-necked aneurysms, is likely to continue. In this chapter, our surgical approach for large wide-necked basilar tip aneurysms using the orbitozygomatic approach, the anterior temporal approach, and hybrid surgery are described.